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General Metal Working

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Metalworking Terms

Abrasion - The process of rubbing, grinding, or wearing away by friction.

 

Abrasion-Resistant Steels - A family of steel products developed for those applications involved in sliding and/or impact abrasion.

Abrasive - A substance capable of grinding away another material.

 

Accordion Reed Steel - Hardened, tempered, polished and blued or yellow flat steel with dressed edges. Carbon content about 1.00. Material has to possess good flatness, uniform hardness and high elasticity.

 

Acid Steel - Steel melted in a furnace with an acid bottom and lining and under a slag containing an excess of an acid substance such as silica. Steel produced in a furnace with an acid lining, i.e. consisting of a siliceous refractory and under a siliceous slag. With an acid slag, carbon, silicon and manganese only are removed so that the pig iron must not contain sulfur and phosphorus in percentages exceeding those permissible for the specification being made. Most steel manufactured today is in furnaces with basic linings.

 

Acid-Brittleness - Brittleness resulting from pickling steel in acid; hydrogen, formed by the interaction between iron and acid, is partially absorbed by the metal, causing acid brittleness.

 

Acid Dipped - Dry rolled finish. Produced by dry cold rolling bichromate dipped alloy with polished rolls resulting in a burnished appearance and retaining the color obtained by dipping (True Metal Color).

 

Acid-Process - A process of making steel, either Bessemer, open-hearth or electric, in which the furnace is lined with a siliceous refractory and for which low phosphorus pig iron is required as this element is not removed.

 

Activation - The changing of the passive surface of a metal to a chemically active state. Contrast with passivation.

 

Age Hardening - Hardening by aging, usually after rapid cooling or cold working. The term as applied to soft, or low carbon steels, relates to a wide variety of commercially important, slow, gradual changes that take place in properties of steels after the final treatment. These changes, which bring about a condition of increased hardness, elastic limit, and tensile strength with a consequent loss in ductility, occur during the period in which the steel is at normal temperatures.

 

Aging - A change in properties that occurs at ambient or moderately elevated temperatures after hot working or a heat-treating operation (quench aging in ferrous alloys), or after a cold working operation (strain aging). The change in properties is often, but not always, due to a phase change (precipitation), but does not involve a change in chemical composition. In a metal or alloy, a change in properties that generally occurs slowly at room temperature and more rapidly at higher temperatures.

 

Air Cooling - Cooling of the heated metal, intermediate in rapidity between slow furnace cooling and quenching, in which the metal is permitted to stand in the open air.

 

Air-Hardening Steel - A steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. Such steels attain their martensitic structure without going through the quenching process. Additions of chromium, nickel, molybdenum and manganese are effective toward this end. The term should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 in. or more in diameter.

 

AISI Steels - Steels of the American Iron and Steel Institute. Common and alloy steels have been numbered in a system essentially the same as the SAE. The AISI system is more elaborate than the SAE in that all numbers are preceded by letters: A represents basic open-hearth alloy steel, B acid Bessemer carbon steel, C basic open- hearth carbon steel, CB either acid Bessemer are basic open-hearth carbon steel, E electric furnace alloy steel.

 

Alclad - Composite sheet produced by bonding either corrosion-resistant aluminum alloy or aluminum of high purity to base metal of structurally stronger aluminum alloy. The coatings are anodic to the core so they protect exposed areas of the core electrolytically during exposure to corrosive environment.

 

Alkaline Cleaner - Uses an alkaline solution, usually sodium hydroxide, to clean residual oils and iron fines left on the strip from the cold reduction process.

 

Allotriomorph - A particle of a phase that has no regular external shape.

 

Allotropy - The property whereby certain elements may exist in more than one crystal structure. The property possessed by certain elements to exist in two or more distinct forms that are chemically identical but have different physical properties. In the case of iron the crystal structure has one form at room temperature and another at high temperature. When heated above 910oC the atomic structure changes from body centered cubic to face centered cubic but reverts again when cooled. The allotropy of iron modifies the solubility of carbon, and it is because of this that steel can be hardened.


Alloy - A substance having metallic properties and composed of two or more chemical elements of which at least one is a metal.

 

Alloy Steel - Steel containing substantial quantities of elements other than carbon and the commonly accepted limited amounts of manganese, sulfur, silicon, and phosphorus. Addition of such alloying elements is usually for the purpose of increased hardness, strength or chemical resistance. The metals most commonly used for forming alloy steels are: nickel, chromium, silicon, manganese tungsten, molybdenum and vanadium, Low Alloy steels are usually considered to be those containing a total of less than 5% of such added constituents.

 

Alloying Element - An element added to a metal, and remaining in the metal, that effects changes in structure and properties.

 

Alpha Brass - A copper-zinc alloy containing up to 38% of zinc. Used mainly for cold working.

 

Alpha Bronze - A copper-tin alloy consisting of the alpha solid solution of tin in copper. Commercial forms contain 4 or 5% of tin. This alloy is used in coinage, springs, turbine, blades, etc.

 

Alpha Iron - The polymorphic form of iron, stable below 1670 (degrees) F. has a body centered cubic lattice, and is magnetic up to 1410 (degrees) F.

 

Aluminizing - Forming an aluminum or aluminum alloy coating on a metal by hot dipping, hot spraying, or diffusion.

 

Aluminum Al

Atomic Number: 13

Atomic Weight: 26.981538

Melting Point: 933.437 K (660.323°C or 1220.581°F) Boiling Point: 2792 K (2519°C or 4566°F)

Density: 2.70 grams per cubic centimeter

Phase at Room Temperature: Solid

A silvery white metal of valence 3. Ductile and malleable; stable against normal atmospheric corrosion, but attacked by both acids and alkalis. Aluminum is used extensively in articles requiring lightness, corrosion resistance, electrical conductivity, etc. Its principal functions as an alloy in steel making; (1) Deoxidizes efficiently. (2) Restricts grain growth (by forming dispersed oxides or nitrides) (3) Alloying element in nitriding steel. Aluminum is also used to deoxidize steel and control grain size. Grain size control is affected by forming a fine dispersion with nitrogen and oxygen, which restricts austenite grain growth. Aluminum is also an extremely effective nitride former in nitriding steels.

 

Aluminum Killed Steel A steel where aluminum has been used as a deoxidizing agent.

 

Amorphous - Noncrystalline.

 

Analog - Full-body electromagnetic induction testing; a type of non-destructive test. (pipe)

 

Angstrom Unit - (A) A unit of linear measure equal to 10(-10)m, or 0.1 nm; not an accepted Si unit, but still sometimes used for small distances such as interatomic distances and some wavelengths.

 

Anisotropy - The characteristics of exhibiting different values of a property in different directions with respect to a fixed reference system in the material.

 

Annealing - (1) Heating to and holding at a suitable temperature and then cooling at a suitable rate, for such purposes as reducing hardness, improving machinability, facilitating cold working, producing a desired microstructure, or obtaining desired mechanical, physical, or other properties. When applicable, the following more specific terms should be used: black annealing, blue annealing, box annealing, bright annealing, flame annealing, graphitizing, intermediate annealing, isothermal annealing, malleableizing, process annealing, quench annealing, recrystallization annealing, and spheroids. When applied to ferrous alloys, the term annealing, without qualification, implies full annealing. When applied to nonferrous alloys, the term annealing implies a heat treatment designed to soften an age-hardened alloy by causing a nearly complete precipitation of the second phase in relatively coarse form. Any process of annealing will usually reduce stresses, but if the treatment is applied for the sole purpose of such relief, it should be designated stress relieving. (2) The process of heating and cooling a cold reduced sheet to induce softness and formability. Two types: box annealing (Cold Sheet Mill) and continuous annealing (Galvanize Mill) Automatic Gauge Control (AGC) Computerized systems used to control and maintain strip thickness; activated through x-ray measurement with feedback loops to control mill screw down pressures and/or speed.

 

Annealing Twin - A twin formed in a metal during an annealing heat treatment.

 

Anodizing (Aluminum Acid Oxide Coating) - A process of coating aluminum by anodic treatment resulting in a thin film of aluminum oxide of extreme hardness. A wide variety of dyes colored coatings are possible by impregnation in process.


Arc Furnace - A steel melting furnace in which heat is generated by an arc between graphite electrodes and the metal. Both carbon and alloy steels are produced in electric arc furnaces and scrap rather than molten metal is used as the base material. Furnaces with capacities up to 200 tons are now in use.

Arc Welding - A group of welding processes wherein the metal or metals being joined are coalesced by heating with an arc, with or without the application of pressure and with or without the use of filler metal.

 

Artifact - In microscopy, a false structure introduced during preparation of a specimen.

 

Artificial Aging - An aging treatment above room temperature.

 

ASME - Abbreviation for Society of Automotive Engineers. This organization has specified common and alloy steels and copper base alloys in accordance with a numerical index system allowing approximation of the composition of the metal. The last two digits always indicate the carbon content, usually within 0.05%. See AISI- SAE specifications. An accelerated corrosion test in which the metal specimens are exposed to a fine mist of salt- water solution either continuously or intermittently.

 

ASTM - Abbreviation for American Society For Testing Material. An organization for issuing standard specifications on materials, including metals and alloys.

 

Atomic-Hydrogen Weld - Arc welding with heat from an arc between two tungsten or other suitable electrodes in a hydrogen atmosphere. The use of pressure and filler metal is optional.

 

Attenuation - The fractional decrease of the intensity of an energy flux, including the reduction of intensity resulting from geometrical spreading, absorption, and scattering.

 

Austenitic Grain Size - The size of the grains in steel heated into the austenitic region.

 

Austempering - Quenching a ferrous alloy from a temperature above the transformation range, in a medium having a rate of heat abstraction high enough to prevent the formation of high-temperature transformation products, and then holding the alloy, until transformation is complete, at a temperature below that of pearlite formation and above that of martensite formation.

 

Austenite - (1) A solid solution of one or more elements in face-centered cubic iron. (2) Phase in certain steels, characterized as a solid solution, usually of carbon or iron carbide. Such steels are known as austenitic. Austenite is stable only above 1333 (degrees) F. in a plain carbon steel, but the presence of certain alloying elements, such as nickel and manganese, stabilizes the austenitic form, even at normal temperatures.

 

Austenitic Steel - Steel, which, because of the presence of alloying elements, such as manganese, nickel, chromium, etc., shows stability of Austenite at normal temperatures.

 

Austenitizing - Forming austenite by heating a ferrous alloy into the transformation range (partial austenitizing) or above the transformation range (complete austenitizing).

 

Autofrettage - Pre-stressing a hollow metal cylinder by the use of momentary internal pressure exceeding the yield strength.

 

Autoradiograph - A radiograph recorded photographically by radiation spontaneously emitted by radioisotopes that are produced in, or added to, the material. This technique identifies the locations of the radioisotopes.

 

Bainite - A eutectoid transformation product of ferrite and a fine dispersion of carbide, generally formed at temperatures below 840 to 930 F (450 to 500 C): upper bainite is an aggregate containing parallel lath-shape units of ferrite, produces the so-called feathery appearance in optical microscopy, and is formed at temperatures above about 660 F (350 C) ; lower bainite consists of individual plate-shape units and is formed at temperatures below about 660 F (350 C). Also, a slender, needle-like (acicular) microstructure appearing in spring steel strip characterized by toughness and greater ductility than tempered Martensite. Bainite is a decomposition product of Austenite best developed at interrupted holding temperatures below those forming fine pearlite and above those giving Martensite.

 

Balanced Steel - Steels in which the deoxidization is controlled to produce an intermediate structure between a rimmed and killed steel. Sometimes referred to as semi- killed steels, they possess uniform properties throughout the ingot and amongst their applications are boiler-plate and structural sections.

 

Bamboo Grain Structure - A structure in wire or sheet in which the boundaries of the grains tend to be aligned normal to the long axis and to extend completely through the thickness.

 

Band Saw Steel (Wood) - A hardened tempered bright polished high carbon cold rolled spring steel strip produced especially for use in the manufacture of band saws for sawing wood, non ferrous metals, and plastics. Usually carries some nickel and with a Rockwell value of approximately C40/45.

 

Banded - The 1" or 1-1/4" strapping that is pulled tight around the body of the coil to keep the wraps tight is still on the coil; not broken

 

Banded Structure - Appearance of a metal showing parallel bands in the direction of rolling or working.

 

Banding - Inhomogeneous distribution of alloying elements or phases aligned in filaments or plates parallel to the direction of working.

 

Bark - Surface of metal, under the oxide-scale layer, resulting from heating in an oxidizing environment. In the case of steel, such bark always suffers from decarburization.

 

Base Box - See Tin Plate Base Box.

 

Base Metal - A metal that oxidizes when heated in air, e.g. lead, copper, tin, zinc, as opposed to noble metals such as gold and platinum.

 

Basic Open Hearth - (See Open Hearth Process.)

 

Basic Oxygen Process - A steel making process wherein oxygen of the highest purity is blown onto the surface of a bath of molten iron contained in a basic lined and ladle shaped vessel. The melting cycle duration is extremely short with quality comparable to Open Hearth Steel.

 

Basic Process - A steel making process either Bessemer, open hearth or electric, in which the furnace is lined with a basic refractory. A slag, rich in lime, being formed and phosphorus removed. BASIC STEEL-(See Basic Process.)

 

Basic Steel - Steel melted in a furnace with a basic bottom and lining and under a slag containing an excess of a basic substance such as magnesia or lime.

 

Bath Annealing - Is immersion is a liquid bath (such as molten lead or fused salts) held at an assigned temperature-when a lead bath is used, the process is known as lead annealing.

 

Bauxite - The only commercial ore of aluminum, corresponding essentially to the formula Al2O3xH2O.

 

Beading - Raising a ridge on sheet metal.

 

Bearing Load - A compressive load supported by a member, usually a tube or collar, along a line where contact is made with a pin, rivet, axle, or shaft.

 

Bearing Strength - The maximum bearing load at failure divided by the effective bearing area. In a pinned or riveted joint, the affective area is calculated as the product of the diameter of the hole and the thickness of the bearing member.

 

Belly Band - The band (strapping) that goes around the outside diameter of a coil.

 

Bend Radius - The inside radius of a bent section,

 

Bend Test - Various tests which is used to ascertain the toughness and ductility of a metal product, in which the material is bent around its axis and/ or around an outside radius. A complete test might specify such a bend to be both with and against the direction of grain. For testing, samples should be edge filed to remove burrs and any edgewise cracks resulting from slitting or shearing. If a vice is to be employed, then you must line the jaws with some soft metal, to permit a flow of the metal in the piece being tested.

 

Beryllium Copper - An alloy of copper and 2-3% beryllium with optionally fractional percentages of nickel or cobalt. Alloys of this series show remarkable age-hardening properties and an ultimate hardness of about 400 Brinell (Rockwell C43). Because of such hardness and good electrical conductivity, beryllium-copper is used in electrical switches, springs, etc.

 

Bessemer Process - A process for making steel by blowing air through molten pig iron contained in a refractory lined vessel so that the impurities are thus removed by oxidation. A method of producing steel, first introduced in the last century, where air is blown under pressure through molten iron to remove the impurities by oxidation. The development of the process has led to the present day Basic Oxygen Steel-making plants that account for bulk production of commercial quality steels in the UK.

 

Beveling - Refers to pipe; the end preparation for field welding of the joint.

 

Billet - A solid semi-finished round or square product that has been hot worked by forging, rolling, or extrusion. An iron or steel billet has a minimum width or thickness of 1 1/2 in. and the cross-sectional area varies from 2 1/4 to 36 sq. in. For nonferrous metals, it may also be a casting suitable for finished or semi-finished rolling or for extrusion.

 

Binary Alloy - An alloy containing two elements, apart from minor impurities, as brass containing the two elements copper and zinc.

 

Black Annealing - A process of box annealing or pot annealing ferrous alloy sheet, strip or wire after hot

working and pickling.

 

Black Oil Tempered Spring Steel Strip (Scale Less Blue) - A flat cold rolled usually .70/.80 medium high carbon steel strip, blue-black in color, which has been quenched in oil and drawn to desired hardness. While it looks and acts much like blue tempered spring steel and carries a Rockwell hardness of C44/47, it has not been polished and is lower in carbon content. Used for less exacting requirements than clock spring steel, such as snaps, lock springs, hold down springs, trap springs, etc. It will take a more severe bend before fracture than will clock spring, but it does not have the same degree of spring-back.

 

Black Plate - A lightweight or a thin uncoated steel sheet or strip so called because of its dark oxide coloring prior to pickling. Two different processes manufacture it. (1) Form sheet bar on single stand sheet mills or sheet mills in tandem. This method is now almost obsolete. (2) On modern, high speed continuous tandem cold reduction mills from coiled hot rolled pickled wide strip into ribbon wound coils to finished gage. Sizes range from 12 to 32 in width, and in thicknesses from 55 lbs. to 275 lbs. base box weight. It is used either as is for stampings, or may be enameled or painted or tin or terne coated.

 

Blast Furnace - A vertical shaft type smelting furnace in which an air blast is used, usually hot, for producing pig iron. The furnace is continuous in operation using iron ore, coke, and limestone as raw materials, which are charged at the top while the molten iron and slag are collected at the bottom and are tapped out at intervals.

 

Blister - A defect in metal, on or near the surface, resulting from the expansion of gas in a subsurface zone. Very small blisters are called pinheads or pepper blisters.

 

Blister Steel - High-carbon steel produced by carburizing wrought iron. The bar, originally smooth, is covered with small blisters when removed from the cementation (carburizing) furnace.

 

Bloom - (1) Ancient Definition: iron produced in a solid condition directly by the reduction of ore in a primitive furnace. The carbon content is variable but usually low. Also known as bloomery iron. The earliest iron making process, but still used in underdeveloped countries. (2) Modern Definition: a semi-finished hot rolled steel product, rectangular in section, usually produced on a blooming mill but sometimes made by forging. (3) A semi-finished hot rolled product, rectangular in cross section, produced on a blooming mill. For iron and steel, the width is not more than twice the thickness, and the cross-sectional area is usually not less than 36 sq. in. Forging sometimes makes iron and steel blooms.

 

Bloomery - A primitive furnace used for direct reduction of ore to iron.

 

Blooming-Mill - A mill used to reduce ingots to blooms, billets slabs, sheet-bar etc.,

 

Blowhole - A cavity which was produced during the solidification of metal by evolved gas, which in failing to escape is held in pockets.

 

Blue Annealing - Heating hot rolled ferrous sheet in an open furnace to a temperature within the transformation range and then cooling in air, in order to soften the metal. The formation of a bluish oxide on the surface is incidental. A process of softening ferrous alloys in the form of hot rolled sheet, by heating in the open furnace to a temperature within the transformation range and then cooling in air. The formation of bluish oxide on the surface is incidental.

 

Blue Brittleness - Reduced ductility occurring as a result of strain aging, when certain ferrous alloys are worked between 300 and 700 (degrees) F. This phenomenon may be observed at the working temperature or subsequently at lower temperatures. Brittleness exhibited by some steels after being heated to some temperature within the

range of 300 (degrees) to 650 (degrees) F, and more especially if the steel is worked at the elevated temperature. Killed steels are virtually free of this kind of brittleness.

 

Bluing - Subjecting the scale-free surface of a ferrous alloy to the action of air, steam, or other agents at a suitable temperature, thus forming a thin blue film of oxide and improving the appearance and resistance to corrosion. NOTE: This term is ordinarily applied to sheet, strip, or finished parts, It is used also to denote the heating of springs after fabrication in order to improve their properties.

 

Body-Centered - Having the equivalent lattice points at the corners of the unit cell, and at its center; sometimes called centered, or space-centered.

 

Bonderizing - The coating of steel with a film composed largely of zinc phosphate in order to develop a better bonding surface for paint or lacquer.

 

Boron B

Atomic Number: 5

Atomic Weight: 10.811

Melting Point: 2348 K (2075°C or 3767°F) Boiling Point: 4273 K (4000°C or 7232°F) Density: 2.37 grams per cubic centimeter

Phase at Room Temperature: Solid

It is gray in color, ignites at about 1112 (degrees) F. and burns with a brilliant green flame, but its melting point in a non-oxidizing atmosphere is about 4000 (degrees) F. Boron is used in steel in minute quantities for one purpose only- to increase the hardenability as in case hardening and to increase strength and hardness penetration. It is usually added between .0005-.003% to significantly increase the hardenability, especially for low carbon alloys. It does not affect the strength of ferrite, therefore not sacrificing ductility, formability or machinability in the annealed state.


Bottle Top Mold - Ingot mold, with the top constricted; used in the manufacture of capped steel, the metal in the constriction being covered with a cap fitting into the bottle-neck, which stops rimming action by trapping escaping gases.

 

Box Annealing - Annealing a metal or alloy in a sealed container under conditions that minimize oxidation. In box annealing a ferrous alloy, the charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly; this process is also called close annealing or pot annealing.

 

Brake - A piece of equipment used for bending sheet; also called a bar folder. If operated manually, it is called a hand brake; if power driven, it is called a press brake.

 

Brale - A diamond penetrator, conical in shape, used with a Rockwell hardness tester for hard metals.

 

Brass - This is one of the most widely used of the copper-zinc alloys; it is malleable and ductile; has excellent cold-working; poor hot working and poor machining properties; develops high tensile strength with cold-working. Temper is imparted by cold rolling and classified in hardness by the number of B&S Gages of rolling (reduction in thickness) from the previous annealing gage. Rated excellent for soft soldering; good for silver alloy brazing or oxyacetylene welding and fair for resistance or carbon arc welding. Used for drawn cartridges, tubes, eyelet machine items, snap fasteners, etc.  Brass (Yellow) - Strip. 65% copper and 35% zinc. Known as 'High Brass' or 'Two to One Brass'. A copper-zinc alloy yellow in color. Formerly widely used but now largely supplanted by Cartridge Brass.

 

Brasses - Copper base alloys in which zinc is the principal alloying element. Brass is harder and mechanically stronger than either of its alloying elements copper or zinc. It is formable and ductile; develops high tensile strength with cold-working and is not heat treatable.

 

Braze Welding - A family of welding procedures where metals are joined by filler metal that has a melting temperature below the solidus of the parent metal, but above 840 (450 C).

 

Brazing - Joining metals by fusion of nonferrous alloys that have melting points above 800 F (425C), but lower than those of the metals being joined. May be accomplished by a torch. Filler metal is ordinarily in rod form in torch brazing; whereas in furnace and dip brazing the work material is first assembled and the filler metal may then be applied as wire, washers, clips, bands, or may be bonded, as in brazing sheet.

 

Break Test (for tempered steel) - A method of testing hardened and tempered high carbon spring steel strip wherein the specimen is held and bent across the grain in a vice-like calibrated testing machine. Pressure is applied until the metal fractures at which point a reading is taken and compared with a standard chart of brake limitations for various thickness ranges.

 

Bridling - The cold working of dead soft annealed strip metal immediately prior to a forming, bending, or drawing operation. A process designed to prevent the formulation of Luder's lines. Caution-Bridled metal should be used promptly and not permitted to (of itself) return to its pre-bridled condition.

 

Bright Annealed Wire - Steel wire bright drawn and annealed in controlled non-oxidizing atmosphere so that surface oxidation is reduced to a minimum and the surface remains relatively bright.

 

Bright Annealing - The process of annealing in a protective atmosphere so as to prevent discoloration of the bright surface desired.

 

Bright Basic Wire - Bright steel wire, slightly softer than Bright Bessemer Wire. Used for round head wood screws, bolts and rivets, electric welded chain, etc.

 

Bright Bessemer Wire - Stiff bright wire of hard temper. Normally wire is drawn down to size without annealing.

 

Bright Dip - An acid solution into which pieces are dipped in order to obtain a clean, bright surface.

 

Bright Drawing - The process of drawing hot rolled steel through a die to impart close dimensional tolerances, a bright, scale free surface, and improved mechanical properties. The product is termed bright steel.

 

Brinell Hardness Test - A common standard method of measuring the hardness of materials. The smooth surface of the metal is subjected to indentation by a hardened steel ball under pressure. A microscope then measures the diameter of the indentation in the material surface, and the hardness value is read from a chart or determined by a prescribed formula.

 

Brittle Fracture - Fracture preceded by little or negligible plastic deformation.

 

Brittleness - The tendency of a metal or material to fracture without undergoing appreciable plastic deformation.

 

Broaching - Multiple shaving, accomplished by pushing a tool with stepped cutting edges along the piece, particularly through holes.

 

Bronze - Primarily an alloy of copper and tin, but additionally, the name is used when referring to other alloys not containing tin, for example, aluminum bronze, manganese bronze, and beryllium bronze.

 

Brown & Sharp Gages (B&S) - A standard series of sizes referred to by numbers, in which the diameter of wire or thickness of sheet metal is generally produced and which is used in the manufacture of brass, bronze, copper, copper-base alloys and aluminum. These gage numbers have a definite relationship to each other. In this system, the decimal thickness is reduced by 50% every six gage numbers- while temper is expressed by the number of B&S gage numbers as cold reduced in thickness from previous annealing. For each B&S gage number in thickness reduction, where is assigned a hardness value of 1/4 hard.

 

Buckle - Bulges and/ or hollows occurring along the length of the metal with the edges remaining otherwise flat. Alternate bulges or hollows recurring along the length of the product with the edges remaining relatively flat. Heating a metal beyond the temperature limits allowable for the desired heat treatment, or beyond the point where serious oxidation or other detrimental action begins.

 

Buffer - A substance added to aqueous solutions to maintain a constant hydrogen-ion concentration, even in the presence of acids or alkalis.

 

Burning - (1) Permanently damaging a metal or alloy by heating to cause either incipient melting or intergranular oxidation. (2) In grinding getting the work hot enough to cause discoloration or to change the microstructure by tempering or hardening. (3) Heating a metal beyond the temperature limits allowable for the desired heat treatment, or beyond the point where serious oxidation or other detrimental action begins.

 

Burnishing - Smoothing surfaces through friction between the material and material such as hardened metal media.

 

Burnt - A definition applying to material which has been permanently damaged by over-heating.

 

Burr - Roughness left by a cutting operation such as slitting, shearing, blanking , etc.

 

Bruise - A raised area in the steel caused by an object going between the work rolls and bruising them.

 

Butcher Saw Steel - A hardened, tempered, and polished high carbon spring steel strip material (carbon content is generally higher than that of a material used for wood band saw applications) with a Rockwell value of roughly C47/49.

 

 

Butt Welding - (1) Joining two edges or ends by placing one against the other and welding them. (2) The type of welding that fuses the head end of one coil to the tail end of another, using heat, without overlapping the strip.

 

Cake - A copper ingot rectangular in cross section intended for rolling.

 

Calcium Ca

Atomic Number: 20

Atomic Weight: 40.078

Melting Point: 1115 K (842°C or 1548°F) Boiling Point: 1757 K (1484°C or 2703°F) Density: 1.54 grams per cubic centimeter Phase at Room Temperature: Solid

Is used in certain steels to control the shape, size and distribution of oxide and/or sulfide inclusions. Benefits may include improved ductility, impact strength and machinability.

 

Camber or Bow - (1) Deviation from edge straightness usually referring to the greatest deviation of side edge from a straight line. (2) Sometimes used to denote crown in rolls where the center diameter has been increased to compensate for deflection cause by the rolling pressure. (3) Edgewise curvature. A lateral departure of a side edge of sheet or strip metal from a straight line.

 

Camera Shutter Steel - Hardened, tempered and bright polished extra flat and extra precision rolled. Carbon content 1.25 - Chromium .15.

 

Canning - A dished distortion in a flat or nearly flat surface, sometimes referred to as oil canning.

 

Capped Steel - Semikilled steel cast in a bottle-top mold and covered with a cap fitting into the neck of the mold. The cap causes to top metal to solidify. Pressure is built up in the sealed-in molten metal and results in a surface condition much like that of rimmed steel.

 

Carbide - A compound of carbon with one or more metallic elements.

 

Carbon C

Atomic Number: 6

Atomic Weight: 12.0107

Melting Point: 3823 K (3550°C or 6422°F) Boiling Point: 4098 K (3825°C or 6917°F) Density: 2.2670 grams per cubic centimeter Phase at Room Temperature: Solid

Carbon has three allotropic modifications, all non-metallic. Carbon is present in practically all ferrous alloys, and has tremendous effect on the properties of the resultant metal. Carbon is also an essential component of the cemented carbides. Its metallurgical use, in the form of coke, for reduction of oxides, is very extensive. Is the most important alloying element which is essential for the formation of cementite, pearlite, spheriodite, bainite, and iron- carbon martensite. Compared to steels with similar microstructures, strength, hardness, hardenability, and ductile- to-brittle transition temperature are increased with increasing carbon content up to approximately .60%. Toughness and ductility of pearlitic steels are decreased with increasing carbon content.

 

Carbon Equivalent - Referring to the rating of weld-ability, this is a value that takes into account the equivalent additive effects of carbon and other alloying elements on a particular characteristic of a steel. For rating of weld- ability, a formula commonly used is: CE = C + (Mn/6) + [(Cr + Mo + V)/5] + [(Ni + Cu)/15].

 

Carbon Free - Metals and alloys which are practically free from carbon.

 

Carbon Potential - A measure of the capacity of an environment containing active carbon to alter or maintain, under prescribed conditions, the carbon concentration in a steel.

 

Carbon Range - In steel specifications, the carbon range is the difference between the minimum and maximum amount of carbon acceptable.

 

Carbon Restoration - Replacing the carbon lost in the surface layer during previous processing by carburizing this layer to substantially the original carbon level.

 

Carbon Steel - (1) Common or ordinary steel as contrasted with special or alloy steels, which contain other alloying metals in addition to the usual constituents of steel in their common percentages. (2) Steel containing carbon up to about 2% and only residual quantities of other elements except those added for deoxidization, with silicon usually limited to 0.60% and manganese to about 1.65%. Also termed plain carbon steel, ordinary steel, and straight carbon steel.

 

Carbonitriding - Introducing carbon and nitrogen into a solid ferrous alloy by holding above Ac1 in an atmosphere that contains suitable gases such as hydrocarbons, carbon monocide, and ammonia. The carbonitrided alloy is usually quench hardened. A case hardening process in which a suitable ferrous material is heated above the lower transformation temperature in a gaseous atmosphere

having a composition that results in simultaneous absorption of carbon and nitrogen by the surface and, by diffusion, creates a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the work piece.

 

Carburizing (Cementation) - A process in which an austenitized ferrous material is brought into contact with a carbonaceous atmosphere having sufficient carbon potential to cause absorption of carbon at the surface and, by diffusion, create a concentration gradient. Introducing carbon into a solid ferrous alloy by holding above Ac1 in contact with a suitable carbonaceous material, which may be a solid,

liquid, or gas. The carburized alloy is usually quench hardened. Adding carbon to the surface of iron-base alloys by absorption through heating the metal at a temperature below its melting point in contact with carbonaceous solids, liquids or gases. The oldest method of case hardening.

 

Cartridge Brass - 70% copper 30% zinc. This is one of the most widely used of the copper-zinc alloys; it is formable and ductile and possesses excellent cold-working, poor hot working and poor machining properties. Rated excellent for soft-soldering; good for silver alloy brazing or oxyacetylene welding and fair for resistance of carbon arc welding. The alloy develops high tensile strength with cold-working. Temper is obtained by cold rolling.

 

Case - In a ferrous alloy, the outer portion that has been made harder than the inner portion, or core.

 

Case Hardening - Carburizing and subsequently hardening by suitable heat-treatment, all or part of the surface portions of a piece of iron-base alloy. Hardening a ferrous alloy so that the outer portion, or case, is made substantially harder than the inner portion, or core. Typical processes used for case hardening are carburizing, cyaniding, carbonitriding, nitriding, induction hardening, and flame hardening. A generic term covering several processes applicable to steel that change the chemical composition of the surface layer by absorption of carbon or nitrogen, or a mixture of the two, and, by diffusion, create a concentration gradient.

 

Cast - (1) A term indicating in the annealed state as Cast Spring Steel Wire. (2) In reference to Bright or Polished Strip Steel or Wire, the word cast implies discoloration as a shadow. (3) A term implying a lack of straightness as in a coil set.

Cast Iron - Iron containing more carbon than the solubility limit in austenite (about 2%).

 

Cast Steel - Steel in the form of castings, usually containing less than 2% carbon. Any object made by pouring molten steel into molds.

 

Casting - (1) An object at or near finished shape obtained by solidification of a substance in a mold. (2) Pouring molten metal into a mold to produce an object of desired shape.

 

Cavitation - The formation and instantaneous collapse of innumerable tiny voids or cavities within a liquid subjected to rapid and intense pressure changes. Cavitation produced by ultrasonic radiation is sometimes used to give violent localized agitation. That caused by severe turbulent flow often leads to cavitation damage.


Cavitation Damage - Wearing away of metal through the formation and collapse of cavities in a liquid.

 

Cementation - (1) Introduction of one or more elements into the outer layer of a metal object by means of diffusion at high temperature. (2) An obsolete process used to convert wrought iron to blister steel by carburizing. Wrought iron bars were packed in sealed chests with charcoal and heated at about 2000 F (1100 C) for 6 to 8 days. Cementation was the predominant method of manufacturing steels particularly high-carbon tool steels, prior to the introduction of the Bessemer and open-hearth methods.

 

Cementite - A compound of iron and carbon known as Iron carbide, which has the approximate chemical formula Fe3C containing 6.69% of carbon. Hard and brittle, it is the hard constituent of cast iron, and the normal form in which carbon is present in steel. It is magnetizable, but not as readily as ferrite. It is characterized by an orthorhombic crystal structure. When it occurs as a phase in steel, the chemical composition will be altered by the presence of manganese and other carbide-forming elements. It has limited substitution solubility for the carbide- forming elements, notably manganese.

 

Centrifugal Casting - A casting made by pouring metal into a mold that is rotated or revolved.

 

Ceramic Tools - Cutting tools made from fused, sintered, or cemented metallic oxides.

 

Cerium Ce

Atomic Number: 58

Atomic Weight: 140.116

Melting Point: 1071 K (798°C or 1468°F) Boiling Point: 3697 K (3424°C or 6195°F) Density: 8.16 grams per cubic centimeter Phase at Room Temperature: Solid

Cerium is the most abundant of the rare earth elements and makes up about 0.0046% of the earth's crust. Today, cerium is primarily obtained through an ion exchange process from monazite sand (Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements. Pure cerium will ignite if it is scratched with a sharp object, but can be safely used if combined with other materials. Cerium is one of the rare earth elements used to make carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Cerium is also a component of Misch metal, a material that is used to make flints for lighters. Cerium is also used as a catalyst to refine petroleum and as an alloying agent to make special metals.

 

Cermet - A powder metallurgy product consisting of ceramic particles bonded with a metal.

 

Chafery - A charcoal-fired furnace used in early iron making processes to reheat a bloom of wrought iron for forging to consolidate the iron and expel entrapped slag.

 

Chamfer - (1) A beveled surface to eliminate an otherwise sharp corner. (2) A relieved angular cutting edge at a tooth corner.

 

Charcoal Tin Plate - Tin Plate with a relatively heavy coating of tin (higher than the Coke Tin Plate grades).

 

Charpy Test - A pendulum-type single-blow impact test in which the specimen usually notched, is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed, as determined by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.

 

Chatter Marks - Parallel indentations or marks appearing at right angles to edge of strip forming a pattern at close and regular intervals, caused by roll vibrations.

 

Chemical Milling - Removing metal stock by controlled selective chemical etching.

 

Chemical Polishing - Improving the specular reflectivity of a metal surface by chemical treatment.

 

Chemical Treatment - A substance (chromic acid) that is applied to hot dip galvanize sheet to prevent the formation of white rust during shipping and storage.

 

Chemistry (of slab) - The chemical composition of the steel that in part determines the physical and mechanical properties of the product.

 

Chipping - A method for removing seams and other surface defects with chisel or gouge so that such defects will not be worked into the finished product. Chipping is often employed also to remove metal that is excessive but not defective. Removal of defects by gas cutting is known as deseaming or scarfing.

 

Chromadizing (Chromodizing, Chromatizing) - Forming an acid surface to improve paint adhesion on aluminum or aluminum alloys, mainly aircraft skins, by treatment with a solution of chromic acid.

 

Chromium Cr

Atomic Number: 24

Atomic Weight: 51.9961

Melting Point: 2180 K (1907°C or 3465°F) Boiling Point: 2944 K (2671°C or 4840°F)


Density: 7.15 grams per cubic centimeter

Phase at Room Temperature: Solid

It is of bright silvery color, relatively hard. It is strongly resistant to atmospheric and other oxidation. It is of great value in the manufacture of Stainless Steel as an iron-base alloy. Chromium plating has also become a large outlet for the metal. Its principal functions as an alloy in steel making; (1) increases resistance to corrosion and oxidation (2) increases harden-ability (3) adds some strength at high temperatures (4) resists abrasion and wear (with high carbon). Straight chromium steels are susceptible to temper embrittlement and can be brittle.

 

Chromium-Nickel Steel - Steel usually made by the electric furnace process in which chromium and nickel participate as alloying elements. The stainless steel of 18% chromium and 8% nickel are the better known of the chromium-nickel types.

 

Chromizing - A surface treatment at elevated temperature, generally carried out in pack, vapor, or salt bath, in which an alloy is formed by the inward diffusion of chromium into the base metal.

 

Cigarette Knife Steel - Hardened, tempered and bright polished, 1.25 Carbon content- Chromium .15. Accurate flatness necessary and a high hardness with Rockwell C 51 to 53. Usual sizes are 4 3/4 wide and 6 wide x .004 to .010.

 

Clad Metal - A composite metal containing two or three layers that have been bonded together. The bonding may have been accomplished by co-rolling, welding, heavy chemical deposition or heavy electroplating.

 

Cladding - A process for covering one metal with another. Usually the surfaces of fairly thick slabs of two metals are brought carefully into contact and are then subjected to co-rolling so that a clad composition results. In some instances a thick electroplate may be deposited before rolling.

 

Cleavage - Fracture of a crystal by crack propagation across a crystallographic plane of low index.

 

Cleavage Fracture - Fracture of a grain, or most of the grains, in a polycrystalline metal by cleavage, resulting in bright reflecting facets.

 

Cleavage Plane - A characteristic crystallographic plane or set of planes in a crystal on which cleavage fracture occurs easily.

 

Cluster Mill - A rolling mill where each of the two working rolls of small diameter is supported by two or more back-up rolls.

 

Cobalt Co

Atomic Number: 27

Atomic Weight: 58.933200

Melting Point: 1768 K (1495°C or 2723°F) Boiling Point: 3200 K (2927°C or 5301°F) Density: 8.86 grams per cubic centimeter Phase at Room Temperature: Solid

A gray magnetic metal, of medium hardness; it resists corrosion like nickel, which it resembles closely; melting point 2696 (degrees) F.; specific gravity 8.9. It is used as the matrix metal in most cemented carbides and is occasionally electroplated instead of nickel, the sulfate being used as electrolyte. Its principal function as an alloy in tool steel; it contributes to red hardness by hardening ferrite.

 

Coefficient of Expansion - The ratio of change in length, area, or volume per degree to the corresponding value at a standard temperature.

 

Cogging - An intermediate rolling process when a hot ingot is reduced to a bloom or slab in a cogging mill.

 

Coil Breaks - Creases or ridges across a metal sheet transverse to the direction of coiling, occasionally occurring when the metal has been coiled hot and uncoiled cold.

 

Coil Set or Longitudinal Curl - A lengthwise curve or set found in coiled strip metals following its coil pattern. A departure from longitudinal flatness. Can be removed by roller or stretcher leveling from metals in the softer temper ranges.

 

Coil Weld - A joint between two lengths of metal within a coil - not always visible in the cold reduced product.

 

Coils - Coiled flat sheet or strip metal- usually in one continuous piece or length.

 

Coining - A process of impressing images or characters of the die and punch onto a plane metal surface.

 

Coke Plate (Hot Dipped Tin Plate) - Standard tin plate, with the lightest commercial tin coat, used for food containers, oil canning, etc. A higher grade is the best cokes, with special cokes representing the best of the coke tin variety. For high qualities and heavier coatings.

 

Cold Drawing - The process of reducing the cross sectional area of wire, bar or tube by drawing the material through a die without any pre-heating. Cold drawing is used for the production of bright steel bar in round square, hexagonal and flat section. The process changes the mechanical properties of the steel and the finished product is accurate to size, free from scale with a bright surface finish.

 

Cold Reduced Strip - Metal strip, produced from hot-rolled strip, by rolling on a cold reduction mill.

 

Cold Reduction - (1) Reduction of metal size, usually by rolling or drawing particularly thickness, while the metal is maintained at room temperature or below the recrystallization temperature of the metal. (2) Reduction of strip thickness through the use of force rather than heat.

 

Cold Rolled Finish - Finish obtained by cold rolling plain pickled sheet or strip with a lubricant resulting in a relatively smooth appearance.

 

Cold Rolling - Rolling metal at a temperature below the softening point of the metal to create strain hardening (work-hardening). Same as cold reduction, except that the working method is limited to rolling. Cold rolling changes the mechanical properties of strip and produces certain useful combinations of hardness, strength, stiffness, ductility and other characteristics known as tempers, which see.

 

Cold Shut - (1) A discontinuity that appears on the surface of cast metal as a result of two streams of liquid meeting and failing to unite. (2) A portion of the surface of a forging that is separated, in part, from the main body of metal by oxide. (3) A condition of brittleness existing in some metals at temperatures below the recrystallization temperature.

 

Cold Treatment - Exposing steel to suitable subzero temperatures (-85 °C, or -120 °F) for the purpose of obtaining desired conditions or properties such as dimensional or microstructural stability. When the treatment involves the transformation of retained austenite, it is usually followed by tempering.

 

Cold Work - Permanent strain produced by an external force in a metal below its recrystallization temperature.

 

Cold Working - Plastic deformation, such as rolling, hammering, drawing, etc., at a temperature sufficiently low to create strain-hardening (work-hardening). Commonly, the term refers to such deformation at normal temperatures.

 

Columbium - See Niobium Nb

 

Columnar Structure - A coarse structure of parallel columns of grains, having the long axis perpendicular to the casting surface.

 

Commercial Bronze - A copper-zinc alloy (brass) containing 90% copper and 10% zinc; used for screws, wire, hardware, etc. Although termed commercial-bronze it contains no tin. It is somewhat stronger than copper and has equal or better ductility.

 

Commercial Quality Steel Sheet - Normally to a ladle analysis of carbon limit at 0.15 max. A Standard Quality Carbon Steel Sheet.

 

Compressive Strength - The maximum compressive stress that a material is capable of developing, based on original area of cross section. In the case of a material which fails in compression by a shattering fracture, the compressive strength has a very definite value. In the case of materials which do not fail in compression by a shattering fracture, the value obtained for compressive strength is an arbitrary value depending upon the degree of distortion that is regarded as indicating complete failure of the material.

 

Constitute - A phase, or combination of phases, that occurs in a characteristic configuration in a microstructure.

 

Constitutional Diagram - A graphical representation of the temperature and composition limits of phase fields in an alloy system as they actually exist under specific conditions of heating and cooling (synonymous with phase diagram). A constitutional diagram may be, or may approximate, and equilibrium diagram, or may represent metastable conditions or phases. Compare equilibrium diagram.

 

Continuous Casting - (1) A method of producing blooms, billets and slabs in long lengths using water cooled moulds. The castings are continuously withdrawn through the bottom of the caster whilst the teeming of the metal is proceeding. The need for primary and intermediate mills and the storage and use of large numbers of ingot moulds is eliminated. The continuous casting process is also used in the production of cast iron, aluminum and copper alloys.(2) A casting technique in which the ingot, billet, tube, or other shape is continuously solidified while it is being poured, and the length is not determined by mold dimensions.

 

Contact Corrosion - When two dissimilar metals are in contact without a protective barrier between them and they are in the presence of liquid, an electrolytic cell is created. The degree of corrosion is dependent on the area in contact and the electro-potential voltage of the metals concerned. The less noble of the metals is liable to be attacked, i.e. zinc will act as a protector of steel in sea water whereas copper or brass will attack the steel in the same environment.

 

Continuous Furnace - Furnace, in which the material being heated moves steadily through the furnace.

 

Continuous Phase - In an alloy or portion of an alloy containing more than one phase, the phase that forms the background or matrix in which the other phase or phases are present as isolated volumes.

 

Continuous Pickling - Passing sheet or strip metal continuously through a series of pickling and washing tanks.


Continuous Strip Mill - A series of synchronized rolling mill stands in which coiled flat rolled metal entering the first pass (or stand) moves in a straight line and is continuously reduced in thickness (not width) at each subsequent pass. The finished strip is recoiled upon leaving the final or finishing pass.

 

Controlled Atmosphere Furnaces - A furnace used for bright annealing into which specially prepared gases are introduced for the purpose of maintaining a neutral atmosphere so that no oxidizing reaction between metal and atmosphere takes place.

 

Controlled Rolling - A hot rolling process in which the temperature of the steel is closely controlled, particularly during the final rolling passes, to produce a fine-grain microstructure.

 

Converter - A furnace in which air is blown through the molten bath of crude metal or matte for the purpose of oxidizing impurities.

 

Cooling Stresses - Stresses developed by uneven contraction or external constraint of metal during cooling; also those stresses resulting from localized plastic deformation during cooling, and retained.

 

Copper Cu

Atomic Number: 29

Atomic Weight: 63.546

Melting Point: 1357.77 K (1084.62°C or 1984.32°F) Boiling Point: 2835 K (2562°C or 4644°F)

Density: 8.933 grams per cubic centimeter

Phase at Room Temperature: Solid

A characteristically reddish metal of bright luster, highly malleable and ductile and having high electrical and heat conductivity; Universally and extensively used in the arts in brasses, bronzes. Universally used in the pure state as sheet, tube, rod and wire and also as alloyed by other elements and an alloy with other metals. It is used in certain steels to improve resistance to atmospheric corrosion.

 

Core - In the case of steel this refers to a component that has been case-hardened where the centre is softer than the hard surface layer or case. It can also be applied to the central part of a rolled rimming steel.

 

Coring - A variation of composition between the center and surface of a unit of structure (such as a dendrite, a grain or a carbide particle) resulting from non-equilibrium growth over a range of temperature.

 

Corrosion - (1) Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents. (2) Deterioration of a metal by chemical or electrochemical reaction with its environment.

 

Corrosion Embrittlement - The embrittlement caused in certain alloys by exposure to a corrosive environment. Such material is usually susceptible to the intergranular type of corrosion attack. The severe loss of ductility of a metal resulting from corrosive attack, usually intergranular and often not visually apparent.

 

Corrosion Fatigue - Effect of the application of repeated or fluctuating stresses in a corrosive environment characterized by shorter life than would be encountered as a result of either their repeated or fluctuating stresses alone or the corrosive environment alone.

 

Corrugated - As a defect. Alternate ridges and furrows. A series of deep short waves.

 

Coupon - A piece of metal from which a test specimen is to be prepared - often an extra piece (as on a casting or forging) or a separate piece made for test purposes (such as a test weldment).

 

Covered Electrode - A filler-metal electrode, used in arc welding, consisting of a metal core wire with a relatively thick covering which provides protection for the molten metal form the atmosphere, improves the properties of the weld metal and stabilizes the arc. The covering is usually mineral or metal powders mixed with cellulose or other binder.

 

Creep - The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength. The effect is particularly important if the temperature of stressing is above the recrystallization temperature of the metal. Time-dependent strain occurring under stress. The creep strain occurring at a diminishing rate is called primary creep; that occurring at a minimum and almost constant rate, secondary creep; that occurring at an accelerating rate, tertiary creep.

 

Creep Limit - (1) The maximum stress that will cause less than a specified quantity of creep in a given time. (2) The maximum nominal stress under which the creep strain rate decreases continuously with time under constant load and at constant temperature. Sometimes used synonymously with creep strength.

 

Creep Strength - (1) The constant nominal stress that will cause a specified quantity of creep in a given time at constant temperature. (2) The constant nominal stress that will cause a specified creep react at constant temperature.

 

Crevice Erosion - A type of concentration-cell corrosion; corrosion of a metal that is caused by the concentration of dissolved salts, metal ions, oxygen, or other gases, and such, in crevices or pockets remote from the principal fluid stream, with a resultant building up of differential cells that ultimately cause deep pitting.


Critical Cooling Rate - The minimum rate of continuous cooling just sufficient to prevent undesired transformations. For steel, the slowest rate at which it can be cooled form above the upper critical temperature to prevent the decomposition of austenite at any temperature above the Ms. The limiting rate at which austenite must be cooled to ensure that a particular type of transformation product is formed.

 

Critical Point(s) - (1) The temperature or pressure at which a change in crystal structure, phase, or physical properties occurs. Same as transformation temperature. (2) In an equilibrium diagram, that specific value of composition, temperature and pressure, or combinations thereof, at which the phases of a heterogeneous systems are in equilibrium. (3) Temperatures at which internal changes or transformations take place within a metal either on a rising or falling temperature.

 

Critical Range - A temperature range in which an internal change takes place within a metal. Also termed transformation range.

 

Critical Strain - That strain which results in the formation of very large grains during recrystallization.

 

Critical Temperature - Synonymous with critical point if pressure is constant.

 

Crop - The defective ends of a rolled or forged product which are cut off and discarded. Cutting off ends of billets ingots or slabs containing pipe or other defects.

 

Cropped Head/Tail - Squaring of the strip by use of mechanical shear.

 

Cross Rolling - (1) The rolling of sheet so that the direction of rolling is changed about 90 (degrees) from the direction of the previous rolling. (2) A (hot) rolling process in which rolling reduction is carried out in a direction perpendicular to, as well as a direction parallel to, the length of the original slab. Rolling at an angle to the long dimension of the metal; usually done to increase width.

 

Crossbow - Deviation from flat across the strip width.

 

Cross Direction (in rolled or drawn metal) - The direction parallel to the axes of the rolls during rolling. The direction at right angles to the direction of rolling or drawing.

 

Crown or Heavy Center - A contour on a sheet or roll where the thickness or diameter increases from edge to center.  The difference in strip thickness from center to edge. Increased thickness in the center of metal sheet or strip as compared with thickness at the edge.

 

Crucible - A ceramic pot or receptacle made of graphite and clay, or clay or other refractory material, and used in the melting of metal. The term is sometimes applied to pots made of cast iron, cast steel or wrought steel.

 

Crucible Steel - High-carbon steel produced by melting blister steel in a covered crucible. Crucible steel was developed by Benjamin Huntsman in about 1750 and remained in use until the late 1940's.

 

Cryogenic Applications - Sub-zero temperature applications.

 

Crystal - (1) A physically homogeneous solid in which the atoms. ions or molecules are arranged in a three- dimensional repetitive pattern. (2) A coherent piece of matter, all parts of which have the same anisotropic arrangement of atom; in metals, usually synonymous with grain and crystallite.

 

Crystalline - Composed of crystals.

 

Crystalline Fracture - A fracture of a polycrystalline metal characterized by a grainy appearance. Compare fibrous fracture.

 

Crystallization - The formation of crystals by the atoms assuming definite positions in a crystal lattice. This is what happens when a liquid metal solidifies. (Fatigue, the failure of metals under repeated stresses, is sometimes falsely attributed to crystallization.)

 

Cube-Centered - Metallography- (concerning space lattices) - Body-centered cubic. Refers to crystal structure.

 

Cup Fracture (Cup-and-Cone Fracture) - Fracture, frequently seen in tensile test pieces of a ductile material, in which the surface of failure on one portion shows a central flat area of failure in tension, with an exterior extended rim of failure in shear. A type of fracture in a tensile test specimen which looks like a cup having the exterior portion extended with the interior slightly depressed.

 

Cupping - The fracture of severely worked rods or wire where one end has the appearance of a cup and the other that of a cone.

 

Cutting Speed - The linear or peripheral speed of relative motion between the tool and work piece in the principal direction of cutting.

 

Cyaniding - Surface hardening of an iron-base alloy article or portion of it by heating at a suitable temperature in contact with a cyanide salt, followed by quenching. Introducing carbon and nitrogen into a solid ferrous alloy by holding above Ac1 in contact with molten cyanide of suitable composition. The cyanided alloy is usually quench hardened.

 

Cyanide Hardening - A process of introducing carbon and nitrogen into the surface of steel by heating it to a suitable temperature in a molten bath of sodium cyanide, or a mixture of sodium and potassium cyanide, diluted with sodium carbonate and quenching in oil or water. This process is used where a thin case and high hardness are required.

 

DC (Direct Chill) Casting - A continuous method of making ingots or billets for sheet or extrusion by pouring the metal into a short mold. The base of the mold is a platform that is gradually lowered while the metal solidifies, the frozen shell of metal acting as a retainer for the liquid metal below the wall of the mold. The ingot is usually cooled by the impingement of water directly on the mold or on the walls of the solid metal as it is lowered. The length of the ingot is limited by the depth to which the platform can be lowered; therefore, it is often called semi continuous casting.

 

Dead Flat - Perfectly flat. As pertaining to sheet, strip or plate. Refer to Stretcher Leveling.

 

Dead Soft Annealing - Heating metal to above the critical range and appropriately cooling to develop the greatest possible commercial softness or ductility.

 

Dead Soft Steel - Steel, normally made in the basic open-hearth furnace or by the basic oxygen process with carbon less than 0.10% and manganese in the 0.20-0.50% range, completely annealed.

 

Dead Soft Temper - Condition of maximum softness commercially attainable in wire, strip, or sheet metal in the annealed state.

 

Deburring - A method whereby the raw slit edge of metal is removed by rolling or filing.

 

Decarburization - Removal of carbon from the outer surface of iron or steel, usually by heating in an oxidizing or reducing atmosphere. Water vapor, oxygen and carbon dioxide are strong decarburizers. Reheating with adhering scale is also strongly decarburizing in

action.  Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium that reacts with carbon.

 

Decoration (of dislocations) - Segregation of solute atoms to the line of a dislocation in a crystal. In ferrite, the dislocations may be decorated with carbon or nitrogen atoms.

 

Deep Drawing - The process of cold working or drawing sheet or strip metal blanks by means of dies on a press into shapes which are usually more or less cup-like in character involving considerable plastic deformation of the metal. Deep-drawing quality sheet or strip steel, ordered or sold on the basis of suitability for deep-drawing

 

Deformative Bands - Generally, bands in which deformation has been concentrated unhomogeneously.

 

Degassing Process (In steel making) - Removing gases from the molten metal by means of a vacuum process in combination with mechanical action.

 

Degenerate Structure - Usually refers to pearlite that does not have an ideally lamellar structure. The degree of degeneracy may vary from slight perturbations in the lamellar arrangement to structures that are not recognizably lamellar.

 

Degreasing - Removal of grease, oil or other lubricant-type materials by immersion in an effective solvent. Usually are used primarily alkaline cleaners, although an organic solvents are useful.

 

Delta Iron - Allotropic modification of iron, stable above 2552 (degrees) F. to melting point. It is of body-centered cubic crystal structure.

 

Dendrite - A crystal that has grown in treelike branching mode. A crystal that has a tree-like branching pattern, being most evident in cast metals slowly cooled through the solidification range.

 

Dendritic Segregation - Inhomogeneous distribution of alloying elements through the arms of dendrites.

 

Deoxidation - (1) Removal of oxygen from molten metals by use of suitable chemical agents. (2) Sometimes refers to removal of undesirable elements other than oxygen by the introduction of elements or compounds that readily react with them. In steel sheet, strip, and wire technology, the term refers to heat treatment in a reducing atmosphere, to lessen the amount of scale.

 

Descaling - It is necessary to remove the scale from hot rolled bars or coil before bright drawing. This is normally carried out by shot blasting or pickling in acid. Other methods of descaling steel products include sand blasting, flame descaling and tumbling.

 

Deseaming - A process of burning out defective areas on the surface of ingots, blooms or billets. The condition of the surface is such that it can then be rolled or forged into a satisfactory product

 

DI (Ideal Diameter) - The diameter of a round steel bar that will harden at the center to a given percent of martensite when subjected to an ideal quench (i.e., Grossman quench severity H=infinity)

 

Diamond Pyramid Hardness Test - This test, more commonly known as the Vickers test, finds greater use in the laboratory than the workshop. It employs a pyramid shaped diamond with an included angle of 136o which is impressed into the specimen using loads of 5 to 120 kg making a small square impression. This test is used for finished or polished components because the impression can be very small. The diamond pyramid hardness number is obtained from a calculation based on measuring the diagonals of the impressions in the steel.

 

Die - The term die is most commonly used in tooling, i.e. press tools "punch and die" but there are many other types of die, e.g. thread cutting dies, forming dies, forging dies, die-casting dies, etc. The term when applied to steel often refers to drawing dies through which hot rolled wire and bar are drawn to produce the finish and dimensional accuracy that is required for bright steel.

 

Die Sinking - Forming or machining a depressed pattern in a die.

 

Die-Lines - Lines of markings daused on drawn or extruded products by minor imperfections in the surface of the die.

 

Diffusion - (1) Spreading of a constituent in a gas, liquid or solid, tending to make the composition of all parts uniform. (2) The spontaneous movement of atoms or molecules to new sites within a material.

 

Dilatometer - An instrument for measuring the expansion or contraction of a solid metal resulting from heating, cooling, polymorphic changes, etc.

 

Discoloration - A change in the visual appearance of the material caused by formation of oxides when exposed to contaminating atmosphere, always at elevated temperatures.

 

Dish - A concave surface departing from a straight line edge to edge. Indicates transverse or across the width.

 

Dislocation - A linear defect in the structure of a crystal.

 

Doctor Blade Steel Strip - A hardened and tempered spring steel strip, usually blued, produced from approximately .85 carbon cold rolled spring steel strip specially selected for straightness and good edges. Sometimes hand straightened or straightened by grinding and cur to desired lengths. This product is used in the printing trade as a blade to uniformly remove excess ink (dope) from the rolls; hence its name.

 

Dolomite - A natural carbonate of calcium and magnesium generally used as a flux in blast furnaces.

 

Drawing - (1) Forming recessed parts by forcing the plastic flow of metal in dies. (2) Reducing the cross section of wire or tubing by pulling it through a die. (3) A misnomer for tempering.

 

Drawing Back - Reheating after hardening to a temperature below the critical for the purpose of changing the hardness of the steel.

 

Draw Quality - More flexible grade of steel.

 

Dressing of coil - Eliminating any damage or defects from the outer or inner diameter of the coil in preparation for shipping.

 

Drill Rod - A term given to an annealed and polished high carbon tool steel rod usually round and center less ground. The sizes range in round stock from .013 to 1 1/2 diameter. Commercial qualities embrace water and oil hardening grades. A less popular but nevertheless standard grade is a non-deforming quality. Drill Rods are used principally by machinists and tool and die makers for punches, drills, taps, dowel pins, screw machine parts, small tools, etc.

 

Drop Forging - A forging made with a drop hammer. An operation in which a metal shape is formed by forcing hot metal into impressions formed in solid blocks of hardened alloy steel, the forging dies. The dies are made in halves, one attached to the rising and falling block of the drop forge and the other to the stationary anvil. Drop forgings are widely used in the automotive industry for crankshafts, stub-axles, gears, etc.

 

Drop Hammer - A forging hammer than depends on gravity for its force.

 

Dry Rolled Finish - Finish obtained by cold rolling on polished rolls without the use of any coolant or metal lubricant, of material previously plain pickled, giving a burnished appearance.

 

Ductile Crack Propagation - Slow crack propagation that is accompanied by noticeable plastic deformation and requires energy to be supplied from outside the body.

 

Ductility - The ability of a material to deform plastically without fracturing, being measured by elongation or reduction of area in a tensile test, by height of cupping in an Erichsen test or by other means. The property of metals that enables them to be mechanically deformed when cold, without fracture. In steel, ductility is usually measured by elongation and reduction of area as determined in a tensile test.


Duplex - A category of stainless steel with high amounts of chromium and moderate nickel content. The duplex class is so named because it is a mixture of austenitic (chromium-nickel stainless class) and ferritic (plain chromium stainless category) structures. This combination was originated to offer more strength than either of those stainless steels. Duplex stainless steels provide high resistance to stress corrosion cracking (formation of cracks caused by a combination of corrosion and stress) and are suitable for heat exchangers, desalination plants, and marine applications.

 

Durability - The ability to accept permanent deformation.

 

Duralumin (obsolete) - The trade name applied to the first aluminum-copper-magnesium type of age- hardenable alloy (17S), which contains nominally 4% Cu, 1/2% Mg. The term is sometimes used to include the class of wrought aluminum-copper-magnesium alloys that harden during aging at room temperature.

 

Dye Penetrant Inspection - A method for detecting surface porosity or cracks in metal. The part to be inspected is cleaned and coated with a dye which penetrates any flaws that may be present. The surface is wiped clean and coated with a white powder. The powder absorbs the dye held in the defects indicating their location.

 

Earing - Wavy projections formed at the open end of a cup or shell in the course of deep drawing because of difference in directional properties. Also termed scallop. The formation of scallops (ears) around the top edge of a drawn part caused by differences in the directional properties of the sheet metal used.

 

Eddy-Current Testing - Nondestructive testing method in which eddy-current flow is induced in the test object. Changes in the flow caused by variations in the object are reflected into a nearby coil or coils for subsequent analysis by suitable instrumentation and techniques.

 

Edge Filing - A method whereby the raw or slit edges of strip metal are passed or drawn one or more times against a series of files, mounted at various angles. This method may be used for deburring only or filing to a specific contour including a completely rounded edge.

 

Edge Strain or Edge Breaks - Creases extending in from the edge of the temper rolled sheet.

 

Edges - Many types of edges can be produced in the manufacture of flat rolled metal products. Over the years the following types of edges have become recognized as standard in their respective fields. . Copper Base Alloys- Slit, Slit and Edge Rolled, Sheared, Sawed, Machined or Drawn . Sheet Steels or Aluminum Sheet- Mill Edge, Slit Edge or Sheared Edge. . Strip Steels and Stainless Strip . No. 1 Edge A- Smooth, uniform, round or square edge, either slit or filed or slit and edge rolled as specified, width tolerance +/- .005. . No. 2 Edge- A natural sound mill edge carried through from the hot rolled band. Has not been slit, filed, or edge rolled. Tolerances not closer than hot- rolled strip limits. . No. 3 Edge - Square, produced by slitting only. Not filed. Width tolerances close. . No. 4 Edge - A round edge produced by edge rolling either from a natural mill edge or from slit edge strip. Not as perfect as No. 1 edge. Width tolerances liberal. . No. 5 Edge - An approximately square edge produced by slitting and filing or slitting and rolling to remove burr. . No. 6 Edge - A square edge produced by square edge rolling, generally from square edge hot-rolled occasionally from slit strip. Width tolerances and finish not as exacting as No. 1 edge.

 

Edging - The dressing of metal strip edges by rolling, filing or drawing.

 

Egg-Shaped Coils - Coil that is sagging at the center.

 

Elastic Limit - The maximum stress to which a material may be subjected without any permanent strain remaining upon complete release of stress. Maximum stress that a material will stand before permanent deformation occurs

 

Elastic Strain - Dimensional changes accompanying stress where the original dimensions are restored upon release of the stress.

 

Elasticity - The property which enables a material to return to its original shape and dimension.

 

Electocleaning (Electrolytic Brightening) - An anodic treatment. A cleaning, polishing, or oxidizing treatment in which the specimen or work is made the anode in a suitable electrolyte; an inert metal is used as cathode and a potential is applied.

 

Electric Arc Furnace (EAF) - Steelmaking furnace where scrap is generally 100% of the charge. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath. Furnaces may be either an alternating current (AC) or direct current (DC). DC units consume less energy and fewer electrodes, but they are more expensive.

 

Electric Furnace Steel - Steel made in any furnace where heat is generated electrically, almost always by arc. Because of relatively high cost, only tool steels and other high-value steels are made by the electric furnace process.

 

Electrical Steels - Steels which are characterized by their magnetic properties and are intended for the manufacture of electrical circuits. They are supplied in the form of cold rolled sheet or strip, generally less than 2mm thick and up to 1500mm wide. Grain orientated steels have preferential magnetic properties in the direction of rolling and non- grain orientated steels have similar magnetic properties both transversely and in the direction of rolling.

 

Electocleaning - (Electrolytic Brightening) An anodic treatment. A cleaning, polishing, or oxidizing treatment in which the specimen or work is made the anode in a suitable electrolyte; an inert metal is used as cathode and a potential is applied.

 

Electrogalvanized - Zinc plating process whereby the molecules on the positively charged zinc anode attach to the negatively charged sheet steel. The thickness of the zinc coating is readily controlled. By increasing the electric charge or slowing the speed of the steel through the plating area, the coating will thicken.

 

Electro-Galvanizing - Galvanizing by Electro deposition of zinc on steel.

 

Electrolytic Tin Plate - Black Plate that has been Tin plated on both sides with commercially pure tin by electrode position.

 

Electron Beam Microprobe Analyzer - An instrument for selective chemical analysis of a small volume of material. An electron beam bombards the area of interest and x-radiation thereby emitted is analyzed in a spectrometer.

 

Electroplating - The production of a thin coating of one metal on another by elect deposition. It is very

extensively used in industry and is continuing to enlarge its useful functions. Various plated metal and combinations thereof are being used for different purposes, to illustrate: 1. Decorative and protection against corrosion; copper, nickel and chromium . 2. Protection against corrosion; cadmium or zinc . 3. Protection against wear; chromium . 4.Build-up of a part or parts undersize; chromium or nickel . 5. Pate for rubber adhesion; brass . 6. Protection against carburization and for brazing operations....copper and nickel The production of a thin coating of one metal on another by electro- deposition. It is very extensively used in industry and is continuing to enlarge its useful functions. Various plated metals and combinations thereof are being used for different purposes.

 

Electropolishing - Improving the specular reflectivity of a metal surface by electrochemical dissolution. Method for imparting brilliance to stainless steel by removing a thin layer of the surface akin to a reverse electroplating process without any working of the underlying metal. Also known as bright finishing. The process highlights surface irregularities (i.e. roll grit pattern, pickle matte, scratches, pits and digs). At best, very special processing is required to enhance surface to be electro polished.

 

Electroslag Refining - A specialized steel making process in which a rolled or a cast ingot in the form of an electrode is re-melted in a water cooled copper mould. The melting is activated by resistive heat generated in a conductive slag. The resulting product has a similar basic chemical composition to the original ingot, but is characterized by high purity and low inclusion content. Typical applications include high integrity components for the aerospace industry.

 

Elevated Temperature Drawing - A process of drawing steel bars at elevated temperatures (normally 250-

300oC) which under optimum conditions produce steels that have higher tensile and yield strengths than those cold drawn with the same degree of reduction.

 

Elongation - (1) Increase in length which occurs before a metal is fractured, when subjected to stress. This is usually expressed as a percentage of the original length and is a measure of the ductility of the metal. (2) In tensile testing, the increase in the gauge length, measured after fracture of the specimen within the gauge length, usually expressed as a percentage of the original gauge length.

 

Elongation After Fracture - In tensile testing, the increase in the gauge length measured after fracture of the specimen within the gauge length and usually expressed as a percentage of the original gauge length.

 

Embossing - Raising or indenting a design in relief on a sheet or strip of metal by passing between rolls of desired pattern.

 

End-Quench Hardenability Test (Jominy Test) - A laboratory procedure for determining the hardenability of a steel or other ferrous alloy. Hardenability is determined by heating a standard specimen above the upper critical temperature, placing the hot specimen in a fixture so that a stream of cold water impinges on one end, and, after cooling to room temperature is

completed, measuring the hardness near the surface of the specimen at regularly spaced intervals along its length. The data are normally plotted as hardness versus distance from the quenched end.

 

Endurance Limit - Same as fatigue limit. Maximum alternating stress which a given material will withstand for an indefinite number of times without causing fatigue failure.

 

Epitaxy - Induced orientation of the lattice of a crystal of a surface deposit by the lattice of the substrate crystal.

 

Equilibrium Diagram - (1) A diagram constructed from thermal and other data showing the limits of composition and temperature within which the various constituents or phases of alloys are stable. (2) A graphical representation of the temperature, pressure and composition limits of phase fields in an alloy system as they exist under conditions of thermo dynamical equilibrium. In condensed systems, pressure is usually considered constant.

 

Equiaxed Crystals - Crystals, each of which has axes approximately equal in length. These are normally present in the centre of a steel ingot.

 

Equiaxed Structure - A structure in which the grains have approximately the same dimensions in all directions.

 

Erichsen Test - A cupping test in which a piece of sheet metal, restrained except at the center, is deformed by a cone-shaped spherical-end plunger until fracture occurs. The height of the cup in millimeters at fracture is a measure of the ductility. Similar to the Olsen Test. Readings are in millimeters.

 

ERW - Electric Resistance Welding (used in formation of pipe).

 

Etchant - A chemical solution used to etch a metal to reveal structural details.

 

Etching - (1) In metallography, the process of revealing structural details by the preferential attack of reagents on a metal surface. (2) Subjecting the surface of a metal to preferential chemical or electrolytic attack to reveal structural details.

 

Eutectic - A mixture of two or more constituents which solidify simultaneously out of the liquid at a minimum freezing point.

 

Eutectoid - (1) An isothermal reversible transformation in which a solid solution is converted into two or more intimately mixed solids, the number of solids formed being the same as the number of components in the system. (2) An alloy having the composition indicated by the eutectoid point on an equilibrium diagram. (3) An alloy structure of intermixed solid constituents formed by a eutectoid transformation.

 

Eutectoid Steel - Steel representing the eutectoid composition of the iron-carbon system, with about 0.80% to

0.83% carbon, the eutectoid temperature being about 1333 (degrees) F. Such steel in the annealed condition consists exclusively of pearlite. Steels with less than this quota of carbon are known as hypo-eutectoid and contain free ferrite in addition to the pearlite. When more carbon is present, the steel is known as hyper-eutectoid and contains free cementite. The presence of certain elements, such as nickel or chromium, lowers the eutectoid carbon content.

 

Exfoliation - A type of corrosion that progresses approximately parallel to the outer surface of the metal, causing layers of the metal to be elevated by the formation of corrosion product.

 

Expander Steel - Hardened and tempered, blue polished. Carbon content about 1.00, Chromium .17. Used for the expanders in oil piston rings. Hardness 30 N 70 to 73. Range of sizes run for grooves 3/32 to 1/4 wide with the steel approximately .003 less than the grooves and thickness from .012 to .020.

 

Extensometer - An apparatus for indicating the deformation of metal while it is subjected to stress.

 

Extensometer Test - The measurement of deformation during stressing in the elastic range, permitting determination of elastic properties such as properties such as proportional limit, proof stress, yield strength by the offset method and so forth. Requires the use of special

testing equipment and testing procedures such as the use of an extensometer or the plotting of a stress-strain diagram.

 

Extra Hard Temper - In brass mill terminology, Extra Hard is six B&S numbers hard or 50.15% reduction from the previous annealing or soft stage.

 

Extra Spring Temper - In brass mill terminology. Extra Spring is ten numbers hard or 68.55% reduction in thickness from the previous annealing or soft stage.

 

Extrusion - Shaping metal into a chosen continuous form by forcing it through a die of appropriate shape. The production of a section by forcing a billet to flow through a die. Often used for producing complex sections, the process is used with both hot and cold metal. Seamless tubes are produced by forcing a hot billet to flow through a die over a mandrel positioned centrally in the die.

 

Eye of Coil - The center of the coil as wound.

 

Face Centered (concerning cubic space lattices) - Having equivalent points at the corners of the unit cell and at the centers of its six faces. A face-centered cubic space lattice is characteristic of one of the close-packed arrangements of equal hard spheres.

 

Fatigue - The phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the tensile strength of the material. Fatigue fractures are progressive, beginning as minute cracks that grow under the action of the fluctuating stress.

 

Fatigue Life - The number of cycles of stress that can be sustained prior to failure for a stated test condition.

 

Fatigue Limit - The maximum stress below which a materiel can presumable endure an infinite number of stress cycles. If the stress is not completely reversed, the value of the mean stress, the minimum stress or the stress ratio should be stated.

 

Fatigue Strength - The maximum stress that can be sustained for a specified number of cycles without failure, the stress being completely reversed within each cycle unless otherwise stated.

 

Ferrite - Generally, a solid solution of one or more alloying elements in the bcc polymorph of iron ( -Fe). Specifically, in carbon steels, the interstitial solid solution of carbon in -Fe. A solid solution of one or more elements in body-centered cubic iron. Unless otherwise designated (for instance, as chromium ferrite), the solute is generally assumed to be carbon. On some equilibrium diagrams there are two ferrite regions separated by an austenite area. The lower area is alpha ferrite; the upper, delta ferrite. If there is no designation, alpha ferrite is assumed.

 

Ferrite Banding - Parallel bands of free ferrite aligned in the direction of working. Sometimes referred to a ferrite streaks.

 

Ferrite-pearlite Banding - Inhomogeneous distribution of ferrite and pearlite aligned in filaments or plates parallel to the direction of working.

 

Ferritic Grain Size - The grain size of the ferric matrix of a steel.

 

Ferroalloy - An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel.

 

Ferro-Manganese - An alloy of iron and manganese (80% manganese) used in making additions of manganese to steel or cast-iron. Ferroalloy, An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel.

 

Ferrous - Related to iron (derived from the Latin ferrum). Ferrous alloys are, therefore, iron base alloys.

 

Fiber or Fibre - (1) The characteristic of wrought metal that indicates directional properties. It is revealed by etching a longitudinal section or manifested by the fibrous appearance of a fracture. It is caused chiefly by extension of the constituents of the metal, both metallic and nonmetallic, in the direction of working. (2) The pattern of preferred orientation of metal crystal after a given deformation process. Direction in which metals have been caused to flow, as by rolling, with microscopic evidence in the form of fibrous appearance in the direction of flow.

 

Fiber Stress - (1) Local stress through a small area (a point or line) on a section where the stress is not uniform, as in a beam under a bending load. (2) Unit stress which exists at any given point in a structural element subjected to load; given as load per unit area.

 

Fibrous Fracture - A fracture whose surface is characterized by a dull gray or silky appearance.

 

Filed Edges - Finished edges, the final contours of which are produced by drawing the strip over a series of small steel files. This is the usual and accepted method of dressing the edges of annealed spring steel strip after slitting in cases where edgewise slitting cracks are objectionable or slitting burr is to be removed.

 

Filler Metal - A third material that is melted concurrently with the parent metal during fusion or braze welding. It is usually, but not necessarily, of different composition from the parent metals.

 

Finery - A charcoal-fueled hearth furnace used in early processes for converting cast iron to wrought iron by melting and oxidizing it in an air blast, then repeatedly oxidizing the product in the presence of a slag. The carbon oxidizes more rapidly than the iron so that a wrought iron of low carbon content is produced.

 

Finished Steel - Steel that is ready for the market without further work or treatment. Blooms, billets, slabs, sheet bars, and wire rods are termed semi-finished produced by the in-the-line thermal treatment following electrode position.

 

Finishing Temperature - The temperature at which hot working is completed.

 

Firecrack - Raised area on the strip caused by a thermal crack on the work roll surface.

 

Fish eyes - Areas on a fractured steel surface having a characteristic white crystalline appearance.

 

Flakes - Short discontinuous internal fissures in ferrous metals attributed to stresses produced by lacalized transformation and decreased solubility of hydrogen during cooling after hot working. In a fractured surface, flakes appear as bright silvery areas; on an etched surface they appear as short discontinuous cracks. Also called shatter cracks and snowflakes.

 

Flame Annealing - A process of softening a metal by the application of heat from a high-temperature flame.

 

Flame Hardening - A process of hardening a ferrous alloy by heating it above the transformation range by means of a high-temperature flame, and then cooling as required.

 

Flapper Valve Steel - An extremely flat, very smooth, very accurate to gage, polished, hardened and tempered spring steel produced from approximately 1.15 carbon. The name is derived from its common and principle usage.

 

Flare Test - A test applied to tubing, involving a tapered expansion over a cone. Similar to pin expansion test.

 

Flash - (1) In forging, the excess metal forced between the upper and lower dies. (2) In die casting, the fin of metal which results form leakage between the mating die surfaces. (3) In resistance butt welding, a fin formed perpendicular to the direction of applied pressure.

 

Flash Welding - A resistance butt welding process in which the weld is produced over the entire abutting surface by pressure and heat, the heat being produced by electric arcs between the members being welded.

 

Flat Latch Needle Steel - Supplied cold rolled and annealed. Carbon content .85. Supplied both in coil and flat length. Used to make flat latch needles which are used in the manufacture of knitted goods.

 

Flat Wire - A flat Cold Rolled, prepared edge section up to 1 1/4 wide, rectangular in shape. Generally produced from hot rolled rods or specially prepared round wire by one or more cold rolling operations, primarily for the purpose of obtaining the size and section desired. May also be produced by slitting cold rolled flat metal to desired with followed by edge dressing.

 

Flow Lines - (1) Texture showing the direction of metal flow during hot or cold working. Flow lines often can be revealed by etching the surface or a section of a metal part. (2) In mechanical metallurgy, paths followed by volume elements of metal during deformation. Always visible to a greater or less degree when a longitudinal section has been subjected to Macro etching, indicating the direction of working or rolling.

 

Flow Stress - The uni-axial true stress required to cause plastic deformation at a specified value of strain. The shear stress required to cause plastic deformation of solid metals.

 

Fluting - Kinking or breakage due to curving of metal strip on a radius so small, with relation to thickness, as to stretch the outer surface above its elastic limit. Not to be confused with the specific product, Fluted Tubes.

 

Flux - (1) In refining, a material used to remove undesirable substances as a molten mixture. It may also be used as a protective covering for molten metal. (2) In welding, a material used to prevent the formation of, or to dissolve and facilitate the removal of, oxides and other undesirable substances.

 

Foil - Metal in sheet form less than 0.006 in. in thickness.

 

Folds - Defects caused in metal by continued fabrication of overlapping surfaces.

 

Forge Welding - Welding hot metal by applying pressure or blows.

 

Forging - Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies.

 

Fractography - Descriptive treatment of fracture, especially in metals, with specific reference to photographs of the fracture surface. Macrofractography involves photographs at low magnification; microfractography, at high magnification.

 

Fracture - Surface appearance of metals when broken.

 

Fracture Test - Breaking a specimen and examining the fractured surface with the unaided eye or with a low- power microscope to determine such things as composition, grain size, case depth, soundness, and presence of defects. Nicking and breaking a bar by means of sudden impact, to enable macroscopic study of the fractured surface.

 

Fragmentation - The subdivision of a grain into small discrete crystallites outlined by a heavily deformed network of intersecting slip bands as a result of cold working. These small crystals or fragments differ from one another in orientation and tend to rotate to a stable orientation determined by the slip systems.

 

Free Machining - Pertains to the machining characteristics of an alloy to which an ingredient has been introduced to give small broken chips, lower power consumption, better surface finish, and longer tool life; among such additions are sulfur or lead to steel, lead to brass, lead and bismuth to aluminum, and sulfur or selenium to stainless steel.

 

Fretting (Fretting Corrosion) - Action that results in surface damage, especially in a corrosive environment, when there is relative motion between solid surfaces in contact under pressure.

 

Friction Gouges or Scratches - A series of relatively short surface scratches variable in form and severity. Refer to Galling.

 

Full Annealing (ferrous materials - (1) Annealing a ferrous alloy by austenitizing and then cooling slowly through the transformation range. The austenitizing temperature to hypo-eutectoid steel is usually above Ac3; and for hypereutectoid steel, usually between Ac1 and Ac (cm). Used principally on iron and steel, means heating the metal to about 100 (degrees) F. above the critical temperature range, followed by soaking at this point and slow cooling below the critical temperature. (2) An annealing treatment in which a steel is ausenitized by heating to a temperature above the upper critical temperature (A3 or Acm) and then cooled slowly to room temperature. A typical cooling rate would be 210F/h 100 C/h. Compare normalizing. Use of the term annealing without qualification implies full annealing.

 

Full Finish Plate - Steel sheet or strip, reduced either hot or cold, cleaned, annealed, and then cold-rolled to a bright finish.

 

Full Hard Temper - (A) (No. 1 Temper) In low carbon sheet or strip steel, stiff and springy, not suitable for bending in any direction. It is the hardest temper obtainable by hard cold rolling. (B) In Stainless Steel Strip, tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Full Hard temper is 185,000 TS, 140,000 YS Min. Term also used in connection with copper base alloys and considered synonymous with Hard Temper.

 

Fusion Welding - Any welding process in which fusion is employed to complete the weld.

 

Gages - Mfrs. standard numbering systems indicating decimal thicknesses or diameters.

 

Galling - (1) The damaging of one or both metallic surfaces by removal of particles from localized areas due to seizure during sliding friction. (2) Developing a condition on the rubbing surface of one or both mating parts where excessive friction between high spots results in localized welding with substantial spalling and a further roughening of the surface.

 

Galvanic Corrosion - Corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes. Where the two dissimilar metals are in contact, the resulting action is referred to as couple action.

 

Galvanizing - Coating steel with zinc and tin (principally zinc) for rust proofing purposes. Formerly for the purpose of galvanizing, cut length steel sheets were passed singly through a bath of the molten metal. Today's galvanizing processing method consists of uncoiling and passing the continuous length of successive coils either through a molten bath of the metal termed Hot Dipped Galvanizing or by continuously zinc coating the uncoiled sheet electrolytically- termed Electro-Galvanizing.

 

Galvanneal Furnace - A furnace which is placed over the strip as it exits the zinc bath for the purpose of producing a fully alloyed iron-zinc coating. The furnace can be gas fired or induction.

 

Gamma Iron - The form of iron stable between 1670 (degrees) F., and 2550 (degrees) F., and characterized by a face-centered cubic crystal structure.

 

Gas Welding - Welding with a gas flame.

Gauge - A term for thickness.

 

GFM - Gyratory Forging Machine - A machine designed to hot forge a cylindrical bar shape while it is turning at speed.

 

Gilding Metal - A copper-zinc alloy containing 95% copper and 5% zinc. While similar to deoxidized copper in physical properties, it is somewhat stronger and very ductile. It has thermal and electrical conductivity slightly better than half that of electrolytic copper and corrosion resistance comparable to copper.

 

Grain - A solid polyhedral (or many sided crystal) consisting of groups of atoms bound together in a regular geometric pattern. In mill practice grains are usually studied only as they appear in one plane. (1) (Direction of) Refers to grain fiber following the direction of rolling and parallel to edges of strip or sheets. (2) To bend across the grain is to bend at right angles to the direction of rolling. (3) To bend with the grain is to bend parallel to the direction of rolling. In steel, the ductility in the direction of rolling is almost twice that at right angles to the direction of rolling. An individual crystal in a polycrystalline metal or alloy, including twinned regions or sub-grains if present.

 

Grain Boundary - Bounding surface between crystals. When alloys yield new phases (as in cooling), grain boundaries are the preferred location for the appearance of the new phase. Certain deterioration, such as season cracking and caustic embrittlement, occur almost exclusively at grain boundaries.

 

Grain-Boundary Liquidation - An advanced stage of overheating in which material in the region of austenitic grain boundaries melts. Also known as burning.

 

Grain-Boundary Sulfide Precipitation - An intermediate stage of overheating in which sulfide inclusions are redistributed to the austenitic grain boundaries by partial solution at the overheating temperature and reprecipitation during subsequent cooling.

 

Grain Coarsening - A heat treatment that produces excessively large austenitic grains.

 

Grain Flow - Fiber like lines appearing on polished and etched sections of forgings, caused by orientation of the constituents of the metal in the direction of working during forging.

 

Grain Growth - An increase in metallic crystal size as annealing temperature is raised; growth occurs by invasion of crystal areas by other crystals. An increase in the average size of the grains in polycrystalline metal or alloy, usually a result of heating at elevated temperature.

 

Grain Size - (1) For metals, a measure of the areas or volumes of grains in a polycrystalline material, usually expressed as an average when the individual sizes are fairly uniform. Grain sizes are reported in terms of grains per unit area or volume, average diameter, or as a grain-size number derived form area measurements. Average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area. Since increase in grain size is paralleled by lower ductility and impact resistance, the question of general grain size is of great significance. The addition of certain metals affects grain size, for example vanadium and aluminum tend to give steel a fine grain. The ASTM has set up a grain size standard for steels, and the McQuaid-Ehn Test has been developed as a method of measurement. (2) Average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area. Since increase in grain size is paralleled by lower ductility and impact resistance, the question of general grain size is of great significance. The addition of certain metals affects grain size, for example vanadium and aluminum ten to give steel a fine grain.

 

Grains - Individual crystals in metals.

 

Granular Fracture - A type of irregular surface produced when metal fractures, characterized by a rough, grain like appearance as differentiated from a smooth silky, or fibrous, type. It can be sub classified into trans-granular and inter-granular forms.. This type of fracture is frequently called crystalline fracture, but the implication that the metal has crystallized is completely misleading.

 

Granulated - A coarse grain or pebbly surface condition which becomes evident during drawing.

 

Granulation - The formation of grains immediately upon solidification.

 

Graphite - The polymorph of carbon with a hexagonal crystal structure.

 

Graphitization - Formation of graphite in iron or steel. Primary graphitization refers to formation of graphite during solidification. Secondary graphitization refers to later formation during heat treatment.

 

Graphitizing - A heating and cooling process by which the combined carbon in cast iron or steel is transformed, wholly or partly, to graphitic or free carbon. Annealing a ferrous alloy in such a way that some or all of the carbon is precipitated as graphite.

 

Gray Cast Iron - A cast iron that gives a gray fracture due to the presence of flake graphite. Often called gray iron.

 

Grinding - Removing material from a work piece with a grinding wheel or abrasive belt.

 

Grinding Cracks - Shallow cracks formed in the surface of relatively hard materials because of excessive grinding heat or the high sensitivity of the material.

 

Ground Flat Stock - Annealed and pre-ground (to close tolerances) tool steel flats in standard sizes ready for tool room use. These are three common grades; water hardening, oil hardening, and air hardening quality.

 

Guide - Device for holding the metal in the proper position, during rolling, or slitting.

 

Guide Scratch - Scratches or marks appearing parallel to edges of cold rolled strip caused by scale or other particles which have become imbedded in or have adhered to the rolling mill guide. Also applies to similar scratches appearing as a result of slitting.

 

Gun Drill - A drill, usually with one or more flutes and with coolant passages through the drill body, used for deep hole drilling.

 

Half Hard Temper - (A) In low carbon cold-rolled strip steel, produced by cold rolling to a hardness next to but somewhat softer than full hard temper. (B) In brass mill terminology, half hard is two B&S numbers hard or 20.70% thickness reduction. (C) In Stainless Steel Strip, Tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Half-Hard Temper 150,000 T.S., 110,000 Y.S.Min.

 

Hammer Forging - Forging in which the work is deformed by repeated blows. Compare with press forging.

 

Hard Chromium - Chromium deposited for engineering purposes, such as increasing the wear resistance of sliding metal surfaces, rather than as a decorative coating. It is usually applied directly to basis metal and is customarily thicker than a decorative deposit.

 

Hard Drawing - Drawing metal wire through a die to reduce cross section and increase tensile strength.

 

Hard Drawn - Wire or tubing drawn to high tensile strength by a high degree of cold work.

 

Hard Drawn Spring Steel Wire - A medium high carbon cold drawn spring steel wire. Used principally for cold wound springs.

 

Hard Temper - (A) (For steel see Full Hard Temper) (B) In brass mill terminology. Hard Temper is four B&S numbers hard or 37.1% reduction.

 

Hardenability - In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.

 

Hardened and Tempered Spring Steel Strip - A medium or high carbon quality steel strip which has been subjected to the sequence of heating, quenching and tempering.

 

Hardening - Increasing hardness by suitable treatment, usually involving heating and cooling. When applicable, the following more specific terms should be used: age hardening, case hardening, flame hardening, induction hardening, precipitation hardening, quench hardening. Any process which increases the hardness of a metal. Usually heating and quenching certain iron base alloys from a temperature either within or above the critical temperature range.

 

Hardness - Degree to which a metal will resist cutting, abrasion, penetration, bending and stretching. The indicated hardness of metals will differ somewhat with the specific apparatus and technique of measuring. For details concerning the various types of apparatus used in measuring hardness, See Brinell Hardness, Rockwell Hardness, Vickers Hardness, Scleroscope Hardness. Tensile Strength also is an indication of hardness.

Hardness (indentation) - Resistance of a metal to plastic deformation by indentation. Various hardness tests such as Brinell, Rockwell and Vickers may be used. In the Vickers test, a diamond pyramid with an included face angle of 136 is used as the indenter.

 

Heat of Steel - The product of a single melting operation in a furnace, starting with the charging of raw materials and ending with the tapping of molten metal and consequently identical in its characteristics.

 

Heat Number - The identification that describes the origin of the slab (heat).

 

Heat Tinting - Coloration of a metal surface through oxidation by heating to reveal details of structure.

 

Heat Treatment - Altering the properties of a metal by subjecting it to a sequence of temperature changes, time of retention at specific temperature and rate of cooling all being as important as the temperature itself. Heat treatment usually markedly affects strength, hardness, ductility, malleability, and similar properties of both metals and their alloys. Heating and cooling a solid metal or alloy in such a way that desired structures, conditions or properties are attained. Heating for the sole purpose of hot working is excluded from the meaning of this term.

 

Heat-Affected Zone - That portion of the base metal which was not melted during brazing, cutting, or welding, but whose microstructure and physical properties were altered by the heat.

 

Hematite - The oxide of iron of highest valency which has a composition close to the stoichiometric composition Fe2O3.

 

High Brass - 65% A copper-zinc alloy containing 35% zinc. Possesses high tensile strength. Used for springs, screws, rivets, etc.

 

HNX Gas - A mixture of hydrogen and Nitrogen gas used to prevent oxidation and to "clean" the strip during the annealing process

 

Homogenizing - (1) Holding at high temperature to eliminate or decrease chemical segregation by diffusion. (2) An annealing treatment carried out at a high temperature, approaching the solidus temperature, for a sufficiently long time that inhomogeneous distributions of alloying elements are reduced by diffusional processes.

 

Honing - Removing stock generally on the internal cylindrical surface of a workpiece with an abrasive stick mounted in a holder.

 

Hooke's Law - Stress is proportional to strain in the elastic range. The value of the stress at which a material ceases to obey Hooke's law is known as the elastic limit.

 

Hot Dip - In steel mill practice, a process whereby ferrous alloy base metals are dipped into molten metal, usually zinc, tin, or terne, for the purpose of fizing a rust resistant coating.

 

Hot Rolled Finish - A dark relatively rough oxidized finish resulting from rolling the metal while hot. May subsequently be pickled or bright dipped but the rough surface remains.

 

Hot Short (Shortness) - Brittleness in hot metal in the hot forming range.

 

Hot Top - (1) A reservoir, thermally insulated or heated, to hold molten metal on top of a mold to feed the ingot or casting as it contracts on solidifying to avoid having pipe or voids.

 

Hot Working - Plastic deformation of metal at a temperature sufficiently high not to create strain hardening. The lower limit of temperature for this process is the re-crystallization temperature.

 

Hydrogen Embrittlement - (1) Brittleness of metal, resulting from the occlusion of hydrogen (usually as a by- product of pickling or by co-deposition in electroplating). (2) A condition of low ductility resulting from hydrogen absorption and internal pressure developed subsequently. Electrolytic copper exhibits similar results when exposed to reducing atmosphere at elevated temperatures.

 

Hypereutectoid Alloy - In a eutectoid system, any alloy containing more than the eutectoid concentration of solute.

 

Hypereutectoid Steel - A steel having more than the eutectoid percentage of carbon.

 

Idiomorphz - A particle of a phase the has a regular external shape.

 

Immersed Scanning - In ultrasonics, a planned, systematic movement of the beam relative to the object being inspected, the search unit being coupled to this object through a column of liquid. In most cases the object and the search unit are submerged in water.

 

Impact Energy (Impact Value) - The amount of energy required to fracture a material, usually measured by means of an Izod or Charpy test. The type of specimen and testing conditions affect the values and therefore should be specified.

 

Impact Test - Test designed to determine the resistance of metal to breakage by impact, usually by concentrating the applied stress to a notched specimen. A test to determine the behavior of materials when subjected to high rates of loading, usually in bending, tension, or torsion. The quantity measured is the energy absorbed in breaking the specimen by a single blow, as in the Charpy or Izod.

 

Impurities - Elements or compounds whose presence in a material is undesired.

 

Inclusions - Particles of impurities (usually oxides, sulfides, silicates, etc.) that are held mechanically or are formed during the solidification or by subsequent reaction within the solid metal. A nonmetallic material in a solid metallic matrix.

 

Indentation Hardness - The resistance of a material to indentation. This is the usual type osf hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load.

 

Induction Hardening - A process of hardening a ferrous alloy by heating it above the transformation range by means of electrical induction, and then cooling as required. Quench hardening in which the heat is generated by electrical induction.

 

Induction Heating - A process of heating by electrical induction.

 

Inert-Gas Shielded-Arc Welding - Arc welding in an inert gas such as argon or helium.

 

Ingot - A casting suitable for hot working or remelting.

 

Ingot Iron - Commercially pure open-hearth iron.

 

Inhibitor - A substance which retards some specific chemical reaction. Pickling inhibitors retard the sissolution of metal without hindering the removal of scale from steel.

 

Intercrystalline - Between crystals, or between grains. Same as inter-granular.

 

Interleaving - The placing of a sheet of paper between two adjacent layers of metal to facilitate handling and shearing of rectangular sheets, or to prevent sticking or scratching.

 

Intermediate Annealing - An annealing treatment given to wrought metals following cold work hardening for the purpose of softening prior to further cold working.

Internal Oxidation - Formation of oxides beneath the surface of a metal.

 

Interrupted Aging - The aging of an alloy at two or more temperatures by steps, and cooling to room temperature after each step. Compare with progressive aging.

 

Interrupted Quenching - Quenching in which the metal object being quenched is removed from the quenching medium while the object is at a temperature substantially higher than that of the quenching medium.

 

Interstitial Solid Solution - A solid solution in which the solute atoms occupy (interstitial) positions between the atoms in the structure of the solvent.

Intracrystalline - Within or across crystals or grains. Same as transcrystalline and transgranular.

 

Investment Casting - (1) Casting metal into a mold produced by surrounding (investing) an expendable pattern with a refractory slurry that sets at room temperature after which the wax, plastic, or frozed mercury pattern is removed through the use of heat. Also called precision casting, or lost-wax process. (2) A casting made by the process.

 

Iron Fe

Atomic Number: 26

Atomic Weight: 55.845

Melting Point: 1811 K (1538°C or 2800°F)


A magnetic silver white metal of high tensile strength, ductile and malleable. Chemically iron is chiefly base forming. The principal forms of commercial iron are steel, cast iron and wrought iron. An element that has an average atomic number of 55.85 and that always, in engineering practice, contains small but significant amounts of carbon. Thus iron-carbon alloys containing less than about 0.1% C may be referred to as irons. Alloys with higher carbon contents are always termed steels.

 

Ironing - Thinning the walls of deep drawn articles by reducing the clearance between punch and die.

 

Isothermal Annealing - A process in which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperature that causes transformation of the austenite to a relatively soft ferrite-carbide aggregate.

 

Isothermal Transformation - A change in phase at any constant temperature.

 

Isothermal Transformation (IT) Diagram - A diagram that shows the isothermal time required for transformation of austenite to commence and to finish as a function of temperature. Same as time-temperature- transformation (TTT) diagram or S-curve.

 

Izod Test - A pendulum type of single-blow impact test in which the specimen, usually notched, is fixed at one end and broken by a falling pendulum. The energy absorbed, as measured by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.

 

Jig Saw Steel - Hardened, tempered and bright polished with round edges. Carbon content .85. Ranges of sizes .039 to 393 in width and .016 to .039 in thickness.

 

Killed Steel - The term killed indicates that the steel has been sufficiently deoxidized to quiet the molten metal when poured into the ingot mold. The general practice is to use aluminum ferrosilicon or manganese as deoxidizing agents. A properly killed steel is more uniform as to analysis and is comparatively free from aging. However, for the same carbon and manganese content Killed Steel is harder than Rimmed Steel. In general all steels above 0.25% carbon are killed, also all forging grades, structural steels from 0.15% to 0.25% carbon and some special steels in the low carbon range. Most steels below 0.15% carbon are rimmed steel. Steel deoxidized with a strong

deoxidizing agent, such as silicon or aluminum, to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification.

 

Kind Band (deformation) - In polycrystalline materials, a volume of crystal that has rotated physically to accommodate differential deformation between adjoining parts of a grain while the band itself has deformed homogeneously. This occurs by regular bending of the slip lamellae along the boundaries of the band.

 

Kip - A load of 1000 lbs.

 

Ladle Analysis - A term applied to the chemical analysis representative of a heat of steel as reported by the producer. It is determined by analyzing a test ingot sample obtained during the pouring of the steel from a ladle.

 

Lamellar Tear - A system of cracks or discontinuities aligned generally parallel to the worked surface of a plate. Usually associated with a fusion weld in thick plate.

 

Laminations - Metal defects with separation or weakness generally aligned parallel to the worked surface of the metal. May be the result of pipe, blisters, seams, inclusions, or segregation elongated and made directional by working. Lamination defects may also occur in metal-powder compacts. An abnormal structure resulting in a separation or weakness aligned generally parallel to the worked surface of the metal.

 

Lap - A surface defect, appearing as a seam, caused by fording over hot metal, fins, or sharp corners and then rolling or forging them into the surface, but not welding them.

 

Lap-Weld - A term applied to a weld formed by lapping two pieces of metal and then pressing or hammering, and applied particularly to the longitudinal joint produced by a welding process for tubes or pipe, in which the edges of the skelp are beveled or scarfed so that when they are overlapped they can be welded together.

 

Lath Martensite - Martensite formed, partly in steel containing less than about 1.0% C and solely in steels containing less than about 0.5% C, as parallel arrays or packets of lath-shape units about 0.1 to 0.3 m thick, and having a habit plane that is close to {111}.

 

Lattice - Space lattice. Lattice lines and lattice planes are lines and planes chosen so as to pass through collinear lattice points, and non-collinear lattice points, respectively.

 

LEAD Pb

Atomic Number: 82

Atomic Weight: 207.2

Melting Point: 600.61 K (327.46°C or 621.43°F)

 

Improves machinability. It does not dissolve in steel but stays as globules. Environmental concerns are resulting in a decreased usage of lead in the steel industry.

 

Leveling - A mechanical process in which the strip is stretched beyond its yield point by bending over small diameter rolls. The purpose is to improve the flatness of characteristics of the strip.

 

Light Metal - One of the low-density metals such as aluminum, magnesium, titanium, beryllium, or their alloys.

 

Liquation - Partial melting of an alloy.

 

Liquidus - In a constitutional diagram, the locus of points representing the temperatures at which various components commence freezing on cooling or finish melting on heating.

 

Lithographic Sheet Aluminum - Sheet having a superior surface on one side with respect to freedom from surface imperfections and supplied with a maximum degree of flatness, for use as a plate in offset printing.

 

Long Terne - A term applying to steel sheets that have been terne coated (Lead and Tin) by immersion in a bath of Terne Metal.

 

Longitudinal Direction - The principal direction of flow in a worked metal.

 

Low Brass - 80% cu. A copper-Zinc alloy containing 20% zinc. Is a light golden color, very ductile, suitable for cupping, drawing, forming, etc. Because of its good strength and corrosion resistance it is used for flexible metal hose, metal bellows, etc.

 

Low Carbon Steels - Contain from 0.10 to 0.30% carbon and less than 0.60% manganese. (The product of Basic Oxygen, Bessemer, Open Hearth or Electric Processes.)

 

Low-Hydrogen Electrode - A covered arc-welding electrode that provides an atmosphere around the arc and molten weld metal which is low in hydrogen.

 

Luders Lines (Steel) - (Characteristic of No. 5 Yemper-Not a defect in No. 5 dead soft temper.) Long vein-like marks appearing on the surface of certain metals, in the direction of the maximum shear stress, when the metal is subjected to deformation beyond the field point.

 

M B Grade - A term applied to Open-Hearth steel wire in the .45/.75 carbon range either hard drawn or oil tempered. Oil tempered wire of M B and W M B types are the most widely used of all spring wires. Oil tempered wire is more suitable to precision forming and casting operations than hard drawn wire, because of close control of tensile strength and superior straightness. . NOTE M B, H B and extra H B designate Basic Open Hearth steels, while W M B, W H B and extra W H B designate Acid Open Hearth Steels. The chemical composition and the mechanical properties are the same for both basic and acid steel.

 

Machinability - This is a generic term for describing the ability of a material to be machined. To be meaningful, machinability must be qualified in terms of tool wear, tool life, chip control, and/or surface finish and integrity. Overall machining performance is affected by a myriad of variables relating to the machining operation and the workpiece. An overall review is provided in the ASM Metals Handbook: Machinability, Ninth Edition, Volume 16, 1989.

 

Machinability Index - A relative measure of the machinability of an engineering material under specified standard conditions.

 

Macro-Etch - Etching of a metal surface for accentuation of gross structural details and defects for observation by the unaided eye or at magnifications not exceeding ten diameters.

 

Macroetch Test - Consists of immersing a carefully prepared section of the steel in hot acid and of examining the etched surface to evaluate the soundness and homogeneity of the product being tested.

 

Macrograph - A photographic reproduction of any object that has not been magnified more than ten times. A graphic reproduction of a prepared surface of a specimen at a magnification not exceeding ten diameters. When photographed, the reproduction is known as a photomacrograph (not a macrophotograph).

 

Macroscopic - Visible either with the naked eye or under low magnification (as great as about ten diameters.

 

Macrostructure - The structure of metals as revealed by examination of the etched surface of a polished specimen at a magnification not exceeding ten diameters.

 

Magnetic-Particle Inspection - A nondestructive method of inspection for determining the existence and extent of possible defects in ferromagnetic materials. Finely divided magnetic particles, applied to the magnetized part, are attracted to and outline the pattern of any magnetic-leakage fields created by discontinuities.


Malleability - The property that determines the ease of deforming a metal when the metal is subjected to rolling or hammering. The more malleable metals can be hammered or rolled into thin sheet more easily than others.

 

Malleabilizing - A process of annealing white cast iron in such a way that the combined carbon is wholly or partly transformed to graphitic or free carbon or, in some instances, part of the carbon is removed completely.

 

Manganese Mn

Atomic Number: 25

Atomic Weight: 54.938049

Melting Point: 1519 K (1246°C or 2275°F) Boiling Point: 2334 K (2061°C or 3742°F) Density: 7.3 grams per cubic centimeter Phase at Room Temperature: Solid

Lustrous, reddish-white metal of hard brittle and, therefore, non-malleable character. The metal is used in large quantities in the form of Spiegel and Ferromanganese for steel manufacture as well as in manganese and many copper-base alloys. Its principal function is as an alloy in steel making: (1) It is ferrite-strengthening and carbide forming element. It increases hardenability inexpensively, with a tendency toward embrittlement when too high carbon and too high manganese accompany each other. (2) It counteracts brittleness from sulfur. It is important because it deoxidizes the melt and facilitates hot working of the steel by reducing the susceptibility to hot shortness. It combines with sulfur to form MnS stringers which increases machinability. Manganese contributes to the effectiveness of normalizing for strengthening, to the formation of fine pearlite, and lowers the Ms temperature, therefore increasing the probability of retained austenite.

 

Manual Welding - Welding where in the entire welding operation is performed and controlled by hand.

 

Martempering - (1) A hardening procedure in which an austenitized ferrous material is quenched into an appropriate medium at a temperature just above the Ms temperature of the material, held in the medium until the temperature is uniform through-out -but not long enough for bainite to form - and then cooled in air. The treatment is frequently followed by tempering. (2) When the process is applied to carburized material, the controlling Ms temperature is that of the case. This variation of the process is frequently called marquenching. Quenching an austenitized ferrous alloy in a medium at a temperature in the upper part of the martensite range, or slightly above that range, and holding it in the medium until the temperature throughout the alloy is substantially uniform. The alloy is then allowed to cool in air through the martensite range.

 

Martensite - (1) In an alloy, a metastable transitional structure intermediate between two allotropic modifications whose abilities to dissolve a given solute differ considerably, the high-temperature phase transformed to martensite depends to a large extent upon the temperature attained in cooling, there being a rather distinct beginning temperature. (2) A metastable phase of steel, formed by a transformation of austenite below the Ms (or Ar) temperature. It is an interstitial supersaturated solid solution of carbon in iron having a body-centered tetragonal lattice.  Its microstructure is characterized by an acicular, or needle-like, pattern. A distinctive needle like structure existing in steel as a transition stage in the transformation of austenite. It is the hardest constituent of steel of eutectoid composition. It is produced by rapid cooling from quenching temperature and is the chief constituent of hardened carbon tool steels. Martensite is magnetic.

 

Martensite Range - The interval between the Ms and Mf temperatures.

 

Matalloid - (a) Element intermediate in luster and conductivity between the true metals and non-metals. Arsenic, antimony, boron, tellurium, and selenium, etc., are generally considered metalloids; frequently one allotropic modification of an element will be non-metallic, another metalloid in character. Obviously, no hard and fast line can be drawn. (b) In steel metallurgy, metalloid has a specialized, even if erroneous, meaning; it covers elements commonly present in simple steel; carbon, manganese, phosphorus, silicon and sulfur.

 

Matrix - The principal phase or aggregate in which another constituent is embedded.

 

Matt or Matte Finish - (Steel) Not as smooth as normal mill finish. Produce by etched or mechanically roughened finishing rolls.

 

Mechanical Polishing - A method of producing a specularly reflecting surface by use of abrasives.

 

Mechanical Properties - The properties of a material that reveal its elastic and inelastic behavior where force is applied, thereby indicating its suitability for mechanical application; for example, modulus of elasticity, tensile strength, elongation, hardness, and fatigue limit. These properties have often been designated as physical properties, but the term mechanical properties is much to be preferred. The mechanical properties of steel are dependent on its microstructure.

 

Mechanical Spring - Any spring produced by cold forming from any material with or without subsequent heat treatment

 

Mechanical Working - Plastic deformation or other physical change to which metal is subjected, by rolling, hammering, drawing., etc. to change its shape, properties or structure.

 

Medium-Carbon Steel - Contains from 0.30% to 0.60% carbon and less than 1.00% manganese. May be made by any of the standard processes.

 

Melting Point - The temperature at which a pure metal, compound or eutectic changes form solid to liquid; the temperature at which the liquid and the solid are in equilibrium.

 

Melting Range - The range of temperature in which an alloy melt; that is the range between solidus and liquidus temperatures.

 

Metal - An opaque, lustrous, elemental substance that is a good conductor of heat and electricity and, when polished, a good reflector or light. Most metals are malleable and ductile and are, in general, denser than other substances.

 

Metal Spraying - A process for applying a coating of metal to an object. The metal, usually in the form of wire, is melted by an oxyhydrogen or oxyacetylene blast or by an electric arc and is applied at high speed by gas pressure against the object being coated.

 

Metallography - The science concerning the constituents and structure of metals and alloys as revealed by the microscope.

 

Metalloid - (a) Element intermediate in luster and conductivity between the true metals and nonmetals. Arsenic, antimony, boron, tellurium, and selenium, etc. are generally considered metalloids; frequently one allotropic modification of an element will be non-metallic, another metalloid in character. Obviously, no hard and fast line can be drawn. lb) In steel metallurgy, metalloid has a specialized, even if erroneous, meaning; it covers elements commonly present in simple steel; carbon manganese, phosphorus, silicon and sulfur.

 

Metalograph - An optical instrument designed for both visual observation and photomicrography of prepared surfaces of opaque materials at magnifications ranging from about 25 to about 1500 diameters.

 

Metastable - Possessing a state of pseudo-equilibrium that has a free energy higher than that of the true equilibrium state but from which a system does not change spontaneously.

 

Mf Temperature - The temperature at which martensitic transformation is essentially complete during cooling after austenitization.

 

Microbands (deformation) - Thin sheet like volumes of constant thickness in which cooperative slip occurs on a fone scale. They are an instability which carry exclusively the deformation at medium strains when normal homogeneous slip is precluded. The sheets are aligned at +/- 55(degrees) to the compression direction and are confined to individual grains, which usually contain two sets of bands. Compare shear bands.

 

Microcrack - A crack of microscopic size.

 

Micrograph - A graphic reproduction of the prepared surface of a specimen at a magnification greater than ten diameters. When photographed, the reproduction is known as a photomicrograph (not a microphotograph).

 

Microstructure - The structure of a prepared surface of a metal as revealed by a microscope at a magnification greater than ten diameters.

 

Mild Steel - Carbon steel containing a maximum of about 0.25% C.

 

Mill Edge - The edge of strip, sheet or plate in the as rolled state. Unsheared.

 

Mill Finish - A surface finish produced on sheet and plate. Characteristic of the ground finish used on the rolls in fabrication.

 

Modulus of Elasticity - A measure of the rigidity of metal. Ratio of stress, within proportional limit, to corresponding strain. Specifically, the modulus obtained in tension or compression is Young's modulus, stretch modulus or modulus of extensibility; the modulus obtained in torsion or shear is modulus of rigidity, shear modulus or modulus of torsion; the modulus covering the ratio of the mean normal stress to the change in volume per unit volume is the bulk modulus. The tangent modulus and secant modulus are not restricted within the proportional limit; the former is the slope of the stress-strain curve at a specified point; the latter is the slope of a line from the origin to a specified point on the stress-strain curve. Also called elastic modulus and coefficient of elasticity.

 

Modulus of Elasticity (tension) - Force which would be required to stretch a substance to double its normal length, on the assumption that it would remain perfectly elastic, i.e., obey Hooke's Law throughout the twist. The ratio of stress to strain within the perfectly elastic range.

 

Mold - A form of cavity into which molten metal is poured to produce a desired shape.

 

Molybdenum - Mo

Atomic Number: 42


Atomic Weight: 95.94

Melting Point: 2896 K (2623°C or 4753°F) Boiling Point: 4912 K (4639°C or 8382°F) Density: 10.2 grams per cubic centimeter Phase at Room Temperature: Solid

Hard, tough metal of grayish-white color, becoming very ductile and malleable when properly treated at high temperatures. Pure molybdenum can best be obtained as a black powder, by reduction of molybdenum trioxide or ammonium molybdate with hydrogen. From this powder, ductile sheet and wire are made by powder metallurgy techniques; these are used in radio and related work. Its principal functions as an alloy in steel making: (1) Raises grain-coarsening temperature of austenite. (2) Deepens hardening. (3) Counteracts tendency toward temper brittleness. (4) Raises hot and creep strength, red hardness. (5) Enhances corrosion resistance in stainless steel. (6) Forms abrasion-resisting particles. It increases hardenability of steels and helps maintain a specified hardenability. It increases high temperature tensile and creep strengths. Molybdenum hardened steels require higher tempering temperatures for softening purposes.

 

Ms Temperature - The temperature at which a martensitic transformation starts during cooling after austenitization.

 

Muntz Metal (A refractory Alloy) - Alpha-beta brass, 60% copper and 40% zinc. Stronger than alpha-brass

and used for castings and hot-worked (rolled, stamped, or extruded) products. High strength brasses are developed from this by adding other elements.

 

Music Wire - A polished high tensile strength cold drawn wire with higher tensile strength and higher torsional strength than any other material available. These high mechanical properties are obtained by a combination of the high carbon content, the patenting treatment and by many continuous passes through drawing dies. The high toughness characteristic of this material is obtained by the patenting. Such wire is purchased according to tensile strength, not hardness.

 

Natural Aging - Spontaneous aging of a supersaturated solid solution at room temperature.

 

NDT - Non-destructive testing. (Used mainly in the Pipe Mill.)

 

Necking - Local reduction of the cross-sectional area of metal by stretching.

 

Needle Cutter Steel - Usually supplied quarter hard rolled, extra precision rolled with sheared edges. Carbon content 1.25 - Chromium .15. Usually supplied in a 2 width from .002 to .035. Used for cutting the eyes of needle and milling the latch in a latch needle.

 

Network Structure - A structure in which the crystals of one constituent are surrounded by envelopes of another constituent which gives a network appearance to an etched test specimen.

 

Neumann Band - A mechanical (deformation) twin in ferrite.

 

Nickel Ni

Atomic Number: 28

 

Atomic Weight: 58.6934

Melting Point: 1728 K (1455°C or 2651°F) Boiling Point: 3186 K (2913°C or 5275°F) Density: 8.912 grams per cubic centimeter

Phase at Room Temperature: Solid

Silvery white, slightly magnetic metal, of medium hardness and high degree of ductility and malleability and resistance to chemical and atmospheric corrosion. Used for electroplating. Used as an alloying agent, it is of great importance in iron-base alloys in stainless steels and in copper-base alloys such as Cupro-Nickel, as well as in nickel-base alloys such as Monel Metal. Its principal functions as an alloy in steel making: (1) Strengthens unquenched or annealed steels. (2) Toughens pearlitic-ferritic steels (especially at low temperature). (3) Renders high-chromium iron alloys austenitic. It is used in low alloy steels to reduce the sensitivity of the steel to variations in heat treatment and distortion and cracking on quenching. It also improves low temperature toughness and hardenability.

 

 

Nickel Silver - Copper base alloys that contain 10-45% Zn. and 5-30% Ni.

 

Nickel Steel - Steel containing nickel as an alloying element. Varying amounts are added to increase the strength in the normalized condition to enable hardening to be performed in oil or air instead of water

 

Niobium Nb (was known as Columbium - Cb)

Atomic Number: 41

Atomic Weight: 92.90638

Melting Point: 2750 K (2477°C or 4491°F) Boiling Point: 5017 K (4744°C or 8571°F) Density: 8.57 grams per cubic centimeter

 

Phase at Room Temperature: Solid

It is steel gray in color and brilliant luster. It is used mainly in the production of stabilized austenitic chromium-nickel steels, also to reduce the air-hardening characteristics in plain chromium steels of the corrosion resistant type. It lowers transition temperature and raises the strength of low carbon steel. Niobium increases strength at elevated temperatures, results in finer grain size and forms stable carbides, lowering the hardenability of the steel.

 

Nitriding - Process of surface hardening certain types of steel by heating in ammonia gas at about 935-1000 (degrees) F., the increase in hardness being the result of surface nitride formation. Certain alloying constituents, principal among them being aluminum, greatly facilitate the hardening reaction. In general, the depth of the case is less than with carburizing. Introducing nitrogen into a solid ferrous alloy by holding at a suitable temperature (below Ac1 for ferritic steels) in contact with a nitrogenous material, usually ammonia of molten cyanide of appropriate composition. Quenching is not required to produce a hard case.

 

Nitriding Steel - Steel which is particularly suited for the nitriding process, that is, it will form a very hard and adherent surface upon proper nitriding (heating in a partially dissociated atmosphere of ammonia gas). Composition usually .20-.40 carbon, .90-1.50 chromium, .15-1.00 molybdenum, and .85-1.20% aluminum.

 

Nitrogen - N

Atomic Number: 7

Atomic Weight: 14.0067

Melting Point: 63.15 K (-210.00°C or -346.00°F) Boiling Point: 77.36 K (-195.79°C or -320.44°F) Density: 0. 0012506 grams per cubic centimeter

Phase at Room Temperature: Gas

increases the strength, hardness and machinability of steel, but it decreases the ductility and toughness. In aluminum killed steels, nitrogen combines with the aluminum to provide grain size control, thereby improving both toughness and strength. Nitrogen can reduce the effect of boron on the hardenability of steels.

 

Nodular Pearlite - Pearlite that has grown as a colony with an approximately spherical morphology.

 

Non-Ferrous Metals - Metals or alloys that are free of iron or comparatively so.

 

Non-Metallic Inclusions - Impurities (commonly oxides), sulphides, silicates or similar substances held in metals mechanically during solidification or formed by reactions in the solid state.

 

Non-Refractory Alloy - A term opposed to refractory alloy. A non-refractory alloy has malleability, that is, ease of flattening when subjected to rolling or hammering.

 

Non-Scalloping Quality Strip Steel - Strip steel ordered or sold on the basis of absence of unevenness, or ears, on the edges of the steel, when subjected to deep drawing.

 

Normalizing - (1) A heat treatment applied to steel, Involves heating above the critical range followed by cooling in still air. Is performed to refine the crystal structure and eliminate internal stress. (2) Heating a ferrous alloy to a suitable temperature above A3 or Acm and then cooling in still air to a temperature substantially below A1. The cooling rate usually is in the range 900 to1800 F/h (500 to 1000C/h).

 

Notch Brittleness - A measure of the susceptibility of a material to brittle fracture at locations of stress concentration. For example, in a notch tensile test a material is said to be notch brittle if its notch strength is less than its tensile strength; otherwise, it is said to be notch ductile.

 

Notch Sensitivity - A measure of the reduction in strength of a metal caused by the presence of stress concentration. Values can be obtained from static, impact or fatigue tests.

 

Nucleation - Initiation of a phase transformation at discrete sites, the new phase growing from nuclei.

 

Nucleus - (1) The first structurally stable particle capable of initiating recrystallization of a phase or the growth of a new phase, and separated form the matrix by an interface. (2) The heavy central core of an atom, in which most of the mass and the total positive electrical charge are concentrated.

 

Number as Pertaining to Hardness - In copper base alloys inductry; temper is referred to as so many numbers hard, i.e. Yellow Brass Half Hard is termed 2 numbers hard. This term is derived from terminology used on the mill floor where by temper or hardness is imparted by cold working and classified as to hardness by the number of Brown & Sharpe gages away from the soft or as-annealed state.

 

OD - Outside Diameter (of coil or pipe)

 

Oil Hardening - A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and quenching in oil.

 

Oil Stain Aluminum - Stain produced by the incomplete burning of the lubricants on the surface of the sheet. Rolling subsequent to staining will change color from darker browns to lighter browns down to white.


Oil-Hardening Steel - Steel adaptable to hardening by heat treatment and quenching in oil.

 

Olsen (Ductility) Test - A method of measuring the ductility and drawing properties of strip or sheet metal which involves determination of the width and depth of impression. The test simulating a deep drawing operation is made by a standard steel ball under pressure, continuing until the cup formed from the metal sample fractures.  Readings are in thousandths of an inch. This test is sometimes used to detect stretcher straining and indicates the surface finish after drawing, similar to the Erichsen ductility test.

 

Open Surface - Rough surface on black plate, sheet or strip, resulting from imperfection in the original steel bars from which the plate was rolled.

 

Open-Hearth Furnace - A reverberatory melting furnace with a shallow hearth and a low roof. The flame passes over the charge in the hearth, causing the charge to be heated both by direct flame and radiation from the roof and sidewalls of the furnace. In ferrous industry, the furnace is regenerative.

 

Open-Hearth Process - Process of making steel by heating the metal in the hearth of a regenerative furnace. In the basic open-hearth steel process, the lining of the hearth is basic, usually magnesite; whereas in the acid open- hearth steel process, an acid material, silica, is used as the furnace lining and pig iron, extremely low in phosphorous (less than 0.04%), is the raw material charged in.

 

Open Welds - A weld that shows an area that is not fused.

 

Orange Peel - A pebble-grain surface which develops in forming of metals having coarse grains.

 

Orange Peel (effect) - A surface roughening (defect) encountered in forming products from metal stock that has a coarse grain size. It is due to uneven flow or to the appearance of the overly large grains usually the result of annealing at too high a temperature. Also referred to as pebbles and alligator skin.

 

Ore - A mineral from which metal is (or may be) extracted.

 

Orientation (crystal) - Arrangement of certain crystal axes or crystal planes in a crystalline aggregate with respect to a given direction or plane. If there is any tendency for one arrangement to predominate, it is known as the preferred orientation; in the absence of any such preference, random orientation exists.

 

Oscillated Wound or Scroll Wound - A method of even winding metal strip or wire on to a reel or mandrel wherein the strands are uniformly over-lapped. Sometimes termed stagger wound or vibrated wound. The opposite of ribbon wound.

 

Overaging - Aging under conditions of time and temperature greater than those required to obtain maximum change in a certain property, so that the property is altered in the direction of the initial value.

 

Overheating - Heating a metal or alloy to such a high temperature that its properties are impaired. When the original properties cannot be restored by further heat treating, by mechanical working, or by combination of working and heat treating, the overheating is known as burning.

 

Oxidation - (1) A reaction in which there is an increase in valence resulting from a loss of electrons. (2) Chemical combination with oxygen to form an oxide. The addition of oxygen to a compound. Exposure to atmosphere sometimes results in oxidation of the exposed surface, hence a staining or discoloration. This effect is increased with temperature increase.

 

Oxide - Compound of oxygen with another element.

 

Oxidized Surface - A surface having a thin, tightly adhering oxidized skin.

 

Oxygen Lance - A length of pipe used to convey oxygen onto a bath of molten metal.

 

Oxygen-Free Copper - Electrolytic copper free from cuprous oxide, produced without the use of residual metallic or metalloidal deoxidizers.

 

Pack Rolling - Hot rolling a pack of two or more sheets of metal; scale prevents the sheets from being welded together. Rolling two or more pieces of thin sheet at the same time, a method usually practiced in rolling sheet into thin foil.

 

Pancake Forging - A rough forged shape which may be obtained quickly with a minimum of tooling. It usually requires considerable machining to attain the finish size.

 

Pancake Grain Structure - A structure in which the lengths and widths of individual grains are large compared to their thicknesses.

 

Pass - A term indicating the process of passing metal through a rolling mill. (1) A single transfer of metal through a stand of rolls. (2) The open space between two grooved rolls through which metal is processed. (3) The weld metal deposited in one run along the axis of a weld.

 

Passivation - The changing of the chemically active surface of a metal to a much less reactive state. Contrast with activation.

 

Patenting - (1) Treatment of steel, usually in wire form, in which the metal is gradually heated to about 1830 (degrees) F., with subsequent cooling, usually in air, in a bath of molten lead, or in a fused salt mixture held between 800 (degrees) F. and 1050 (degrees) F.  (2) A heat treatment applied to medium and high-carbon steel prior to cold drawing to wire. The treatment involves austenitization followed by isothermal transformation at a temperature that produces a microstructure of very fine pearlite.

 

Pattern Welding - A process in which strips or other small sections of iron or steel are twisted together and then forge welded. Homogeneity and toughness are thereby improved. A regular decorative pattern can be developed in the final product. Commonly used for making swords as early as the 3rd century A.D.

 

Patterned or Embossed Sheet - A sheet product on which a raised or indented pattern has been impressed on either on or both surfaces by the use of rolls.

 

Pearlite - A eutectoid transformation product of ferrite and cementite that ideally has a lamellar structure but that is always degenerate to some extent. Lamellar structure resembling mother of pearl. A compound of iron and carbon occurring in steel as a result of the transformation of austenite into aggregations of ferrite and iron carbide.

 

Peening - Mechanical working of metal by hammer blows or shot impingement.

 

Penetrant Inspection - A method of non-destructive testing for determining the existence and extent of discontinuities that are open to the surface in the part being inspected. The indications ore made visible through the use of a dye or fluorescent chemical in the liquid employed as the inspection medium.

 

Peritectic - An isothermal reversible reaction in which a liquid phase reacts with a solid phase to produce another solid phase.

 

Permalloy - Nickel alloys containing about 20 to 60% Fe, used for their high magnetic permeability and electrical resistivity.

 

Permanent Set - Non-elastic or plastic, deformation of metal under stress, after passing the elastic limit.

 

Phase - A physically homogeneous and distinct portion of a material system.

 

Phase Diagram - Synonymous with constitutional diagram.

 

Phosphor Bronze - Copper base alloys, with 3.5 to 10% of tin, to which has been added in the molten state phosphorus in varying amounts of less than 1% for deoxidizing and strengthening purposes. Because of excellent toughness, strength, fine grain, resistance to fatigue and wear, and chemical resistance, these alloys find general use as springs and in making fittings. It has corrosion resisting properties comparable to copper.

 

Phosphor Bronze Strip - A copper-base alloy containing up to 10% tin, which has been deoxidized with phosphorus in varying amounts of less than 1%. Temper is imparted by cold rolling, resulting in greater tensile strength and hardness than in most copper-base alloys or either of its alloying elements copper or tin. The various tempers from One Number Hard to Ten Numbers Hard are classified in hardness by the number of B&S Gages reduction in dimension from the previous soft or as-annealed state. Phosphor Bronze is not heat treatable for purposes of hardness development. It does not withstand elevated temperatures very well and should not be used in service above 225 (degrees) F. even after stress relieving treatment at 325 (degrees) to 350 (degrees) F. It has excellent electrical properties, corrosion resistant comparable to copper; great toughness and resistance to fatigue. Rated good for soft soldering, silver alloy brazing, oxyacetylene, carbon arc and resistance welding.

 

Phosphorus P

Atomic Number: 15

Atomic Weight: 30.973761

Melting Point: 317.30 K (44.15°C or 111.47°F) Boiling Point: 553.65 K (280.5°C or 536.9°F) Density: 1.82 grams per cubic centimeter Phase at Room Temperature: Solid

Non-metallic element occurring in at least three allotropic forms; melting point 111 (degrees) F.; boiling point 536 (degrees) F.; specific gravity 1.82. In steels it is usually undesirable with limits set in most specifications. However, it is specified as an alloy in steel to prevent the sticking of light-gage sheets; to a degree it strengthens low carbon steel; increases resistance to corrosion, and improves machinability in free-cutting steels. In the manufacture of Phosphor Bronze it is used as a deoxidizing agent.

 

Photomicrograph - A photographic reproduction of any object magnified more than ten diameters. The term micrograph may be used.

 

Physical Properties - Those properties familiarly discussed in physics, exclusive of those described under mechanical properties; for example, density, electrical conductivity, co-efficient of thermal expansion. This term often has been used to describe mechanical properties, but this usage is not recommended.

Properties other than mechanical properties, that pertain to the physical nature of a material; e.g., density, electrical conductivity, thermal expansion, reflectivity, magnetic susceptibility, etc.


Pickling - An operation by which surface oxide (scale) is removed by chemical action. Sulfuric acid is typically used for carbon and low-alloy steels. After the acid bath, the steel is rinsed in water.

 

Pickling Patch - A defect in tin plate, galvanized or terne plated steel due to faulty pickling, leaving areas from which the oxide has not been completely removed.

 

Pig Iron - Iron produced by reduction of iron ore in a blast furnace. Pig iron contains approximately 92% iron and about 3.5% carbon. Balance largely silicone and manganese with small percentages of phosphorus, sulphur, and other impurities.

 

Piling - A process in which several bars are stacked and hot rolled together with the objective of improving the homogeneity of the final product. Used in primitive iron making.

 

Pin Expansion Test - A test for determining the ability of tubes to be expanded or for revealing the presence of cracks or other longitudinal weaknesses, made by forcing a tapered pin into the open end of a tube.

 

Pinchers - Long fern like creases usually diagonal to the direction of rolling.

 

Pinholes - Microscopic imperfection of the coatings, that is, microscopic bare spots, also microscopic holes penetrating through a layer or thickness of light gage metal.

 

Pipe - (1) The central cavity formed by contraction in metal, especially ingots, during solidification. (2) The defect in wrought or cast products resulting from such a cavity. (3) An extrusion defect due to the oxidized surface of the billet flowing toward the center of the rod at the back end. (4) A tubular metal product, cast or wrought.

 

Pipe (defect) - Contraction cavity, essentially cone-like in shape, which occurs in the approximate center, at the top and reaching down into a casting; caused by the shrinkage of cast metal.

 

Pit (defect) - A sharp depression in the surface of the metal.

 

Pitting - Forming small sharp cavities in a metal surface by non-uniform electro-deposition or by corrosion.

 

Planimetric Method - A method of measuring grain size, in which the grains within a definite area are counted.

 

Planishing - Producing a smooth surface finish on metal by rapid succession of blows delivered by highly polished dies or by a hammer designed for the purpose, or by rolling in a planishing mill.

 

Plastic Deformation - Deformation that remains, or will remain, permanent after release of the stress that caused it.

 

Plasticity - The ability of a metal to be deformed extensively without rupture.

 

Plate - A flat-rolled metal product of some minimum thickness and width arbitrarily dependent on the type of metal.

 

Plate Martensite - Martensite formed, partly in steels containing more than about 0.5% C and solely in steels containing more than about 1.0% C, as ventricular-shape plates on irrational habit planes that are near (225)A, or {259}A in very-high-carbon steels

 

Plating - A thin coating of metal laid on another metal.

 

Polished Surface - The finish obtained by buffing with rouge or similar fine abrasive, resulting in a high gloss or polish.

 

Polishing - Producing a specularly reflecting surface.

 

Polycrystalline - Comprising an aggregate of more than one crystal, and usually a large number of crystals.

 

Polymorphism - The ability of a material to exist in more than one crystallographic structure. Numerous metals change in crystallographic structure at transformation temperatures during heating or cooling. If the change is reversible, it is allotropy. The allotropy of iron, particularly the changes between the alpha body-centered and the gamma face centered form, is of fundamental importance in the hardening of steel.

 

Postheating - Heating weldments immediately after welding, for tempering, for stress relieving, or for providing a controlled rate of cooling to prevent formation of a hard or brittle structure.

 

Pot - A vessel for holding molten metal. Also used to refer to the electrolytic reduction cell employed in winning certain metals, such as aluminum, from a fused electrolyte.

 

Pot Annealing - Is the same as box annealing.

 

Pouring - The transfer of molten metal from the ladle into ingot molds or other types of molds; for example, in castings.

 

Powder Metallurgy - The art of producing metal powders and of utilizing metal powders for the production of massive materials and shaped objects.


Precipitation Hardening - Hardening caused by the precipitation of a constituent form a supersaturated solid solution.

 

Precipitation Heat Treatment - Nonferrous metal. Any of the various aging treatments conducted at elevated temperatures to improve certain of the mechanical properties through precipitation from solid solution.

 

Preferred Orientation - A condition of a polycrystalline aggregate in which the crystal orientations are not random.

 

Preheating - (1) A general term used to describe heating applied as a preliminary to some further thermal or mechanical treatment. (2) A term applied specifically to tool steel to describe a process in which the steel is heated slowly and uniformly to a temperature below the hardening temperature and is then transferred to a furnace in which the temperature is substantially above the preheating temperature. (3) Heating a metal to a relatively high temperature for a relatively long time in order to change the structure before working. Ingots are homogenized by preheating.

 

Press Forging - Forging metal, usually hot, between dies in a press.

 

Primary Crystal - The first type of crystal that separates from a melt during solidification.

 

Primes - Metal products, principally sheet and plate, of the highest quality and free from visible defects.

 

Process Annealing - In the sheet and wire industries, heating a ferrous alloy to a temperature close to, but below, the lower limit of the transformation range and then cooling, in order to soften the alloy for further cold working. This process is applied in order to soften the alloy for further cold working.

 

Proeutectoid (phase) - Particles of a phase that precipitate during cooling after austenitizing but before the eutectoid transformation takes place.

 

Progressive Aging - An aging process in which the temperature of the alloy is continuously increased during the aging cycle. The temperature may be increased in steps or by any other progressive method. Compare with interrupted aging.

 

Proof Stress - (1) The stress that will cause a specified small permanent set in a material. (2) A specified stress to be applied to a member or structure to indicate its ability to withstand service loads.

 

Propertional Limit - The greatest stress that the material is capable of sustaining without a deviation from the law of proportionally of stress to strain (Hooke's Law).

 

Puddling Process - A process for making wrought iron in which cast ore is melted in a hearth furnace and rabbled with slag and oxide until a pasty mass is obtained. This process was developed by Henry Cort about 1784 and remained in use until 1957, although on a very small scale during the present century.

 

Pulse-Echo Method - A nondestructive test in which pulses of energy are directed onto a part, and the time for the echo to return from one or more reflecting surfaces is measured.

 

Punch - The movable part that forces the metal into the die in equipment for sheet drawing, blanking, coining, embossing and the like.

 

Punching - Shearing holes in sheet metal with punch and die.

 

Pyrometer - An instrument of any of various types used for measuring temperatures.

 

Quarter Hard (No. 3 Temper) - (A) In low carbon cold-rolled strip steel, a medium soft temper produced by a limited amount of cold rolling after annealing. (B) In brass mill terminology. Quarter hard is one B and S number hard or 10.95% reduction. (C) In stainless steel terminology tempers are based on minimum tensile, or yield strength. For Chromium-Nickel grades Quarter Hard Temper is 125,000 T. S., 75,000 Y.S. min.

 

Quench Aging - Aging that occurs after quenching following solution heat treatment.

 

Quench Hardening - A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite. Hardening a ferrous alloy by austenitizing and then cooling rapidly enough so that some or all of the austenite transforms to martensite. The austenitizing temperature for hypoeutectoid steels is usually above Ac3 and for hypereutectoid steels usually between Ac1 and Ac (cm).

 

Quenching - In the heat treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil or water. In the case of most copper base alloys, quenching has no effect other than to hasten cooling. A treatment consisting of heating uniformly to a predetermined temperature and cooling rapidly in air or liquid medium to produce a desired crystalline structure.

 

Radiant Tube Annealing Box - A box which is heated, inside, by means of tubes in which gas is burned; the hot tubes radiate their heat to the covered pile of metal, standing on the base of the box. Usually a protective atmosphere is maintained in the box to protect the metal from oxidation.

 

Radiography - A nondestructive method of internal examination in which metal objects are exposed to a beam of X-ray or gamma radiation. Differences in thickness, density or absorption, caused by internal defects or inclusions, are apparent in the shadow image either on a fluorescent screen or on photographic film placed behind the object.

 

Ragged Edges - Edges of Sheet or Strip which are torn, split, cracked, ragged or burred or otherwise disfigured.

 

Recarburizing - (1) Increasing the carbon content of molten cast iron or steel by adding carbonaceous material, high-carbon pig iron or a high-carbon alloy. (2) Carburizing a metal part to return surface carbon lost in processing.

 

Reciprocal Lattice (for a crystal) - A group of points arranged about a center in such a way that the line joining each point of the center is perpendicular to a family of planes in the crystal, and the length of this line is inversely proportional to their interplanar distance.

 

Recovery - (1) The removal of residual stresses by localized plastic flow as the result of low-temperature annealing operations; performed on cold worked metals without altering the grain structure or strength properties substantially.

 

Recrystallization - (1) The change from one crystal structure to another, as occurs on heating or cooling through a critical temperature. (2) The formation of a new, strain-free grain structure from that existing in cold worked metal, usually accomplished by heating. (3) A process whereby a distorted grain structure of cold worked metals is replaced by a new, stress-free grain structure as a result of annealing above a specific minimum temperature for a specific time.

 

Recrystallization Temperature - The approximate minimum temperature at which complete recrystallization of a cold worked metal occurs within a specified time.

 

Recystallization Annealing - Annealing cold worked metal to produce a new grain structure without a phase change.

 

Red Brass - 85% Copper -- A copper-zinc alloy containing approximately 15% zinc, used for plumbing pipe, hardware, condenser tubes. Because of its color, is used or vanity cases, coins, plaques, badges, etc. It is somewhat stronger than commercial bronze and is hardened more rapidly by cold working.

 

Red Shorness - Brittleness in steel when it is red hot.

 

Reduction of Area - (1) Commonly, the difference, expressed as a percentage of original area, between the original cross-sectional area of a tensile test specimen and the minimum cross-sectional area measured after complete separation. (2) The difference, expressed as a percentage of original area, between original cross- sectional area and that after straining the specimen.

 

Refining Temperature - A temperature, usually just higher than the transformation range, employed in the heat treatment of steel to refine the structure -- in particular, the grain size.

 

Reflector Sheet - An alclad product containing on one side a surface layer of high-purity aluminum superimposed on a core or base alloy of commercial-purity aluminum or an aluminum-manganese alloy. The high- purity coating imparts good polishing characteristics and the core gives adequate strength and formability.

 

Refractory - A heat-resistant material, usually nonmetallic, which is used for furnace linings and such.

 

Refractory Alloy - A term applied to those alloys which due to hardness or abrasiveness present relative difficulty in maintaining close dimensional tolerances.

 

Refractory Metal - A metal having an extremely high melting point. In the broad sense, it refers to metals having melting points above the range of iron, cobalt, and nickel.

 

Rephosphorizing (Steel) - A Ladle-chemical treatment consisting of the addition of phosphorus as a work hardening agent when temper rolling black plate or sheet steel resulting in greater hardness and stiffness and with a corresponding loss in ductility. . NOTE: Black Plate in tempers T5 and T6 (R/B range 68/84) are temper rolled from Rephosphorized steel.

 

Residual Elements - Small quantities of elements unintentionally present in an alloy.

 

Residual Stress - Stress present in a body that is free of external forces or thermal gradients. Macroscopic stresses that are set up within a metal as the result of non-uniform plastic deformation. This deformation may be caused by cold working or by drastic gradients of temperature from quenching or welding.

 

Residuals - 'Incidental' or 'tramp' elements not named in a specification. These inclusions are usually due to contaminated scrap.

 

Resilience - The tendency of a material to return to its original shape after the removal of a stress that has produced elastic strain.

 

Resistance Welding - A type of welding process in which the work pieces are heated by the passage of an electric current through the contact. Such processes include spot welding, seam or line welding and percussion welding. Flash and butt welding are sometimes considered as resistance welding processes.

 

Resolution - The capacity of an optical or radiation system to separate closely spaced forms or entities; also, the degree to which such forms or entities can be discriminated.

 

Resulfurized Steel - Steel to which sulfur has been added in controlled amounts after refining. The sulfur is added to improve machinability.

 

Ribbon Wound - A term applied to a common method of winding strip steel layer upon layer around an arbor or mandrel.

 

Riffles - Waviness at the edge of sheet or strip.

 

Rimmed Steel - Low-carbon steel in which incomplete deoxidation permits the metal to remain liquid at the top of the ingot, resulting in the formation of a bottom and side rim of considerable thickness. The rim is of somewhat purer composition than the original metal poured. If the rimming action is stopped shortly after pouring of the ingot is completed, the metal is known as capped steel. Most steels below 0.15% carbon are rimmed steels. For the same carbon and manganese content rimmed steel is softer than killed steel.

 

Ripple (defect) - A slight transverse wave or shadow mark appearing at intervals along the piece.

 

Rockwell Hardness (Test) - A standard method for measuring the hardness of metals. The hardness is expressed as a number related to the depth of residual penetration of a steel ball or diamond cone (brale) after a minor load of 10 kilograms has been applied to hold the penetrator in position. This residual penetration is automatically registered on a dial when the major load is removed from the penetrator. Various dial readings combined with different major loads, five scales designated by letters varying from A to H; the B and C scales are most commonly in use.

 

Roll Forming - An operation used in forming sheet. Strips of sheet are passed between rolls of definite settings that bend the sheet progressively into structural members of various contours, sometimes called molded sections.

 

Rolled Edges - Finished edges, the final contours of which are produced by side or edging rolls. The edge contours most commonly used are square corners, rounded corners and rounded edge.

 

Rolled In Scale - A surface defect consisting of scale partially rolled into the surface of the sheet.

 

Roller Leveling - Passing sheet or strip metal through a series of staggered small rolls so as to flatten the metal. This method is relatively ineffective in removing defects such as buckles, wavy edges, corrugations, twists, etc., or from steel in the higher hardness ranges.

 

Rolling - A term applied to the operation of shaping and reducing metal in thickness by passing it between rolls which compress, shape and lengthen it following the roll pattern. Reducing the cross-sectional area of metal stock, or otherwise shaping metal products, through the use of rotating rolls.

 

Rolling Direction (in rolled metal) - The direction, in the plane of the sheet, perpendicular to the axes of the rolls during rolling.

 

Rolling Mills - Equipment used for rolling down metal to a smaller size or to a given shape employing sets of rolls the contours of which determine or fashion the product into numerous intermediate and final shapes, e.g., blooms, slabs, rails, bars, rods, sections, plates, sheets and strip.

 

Rotary Shear (Slitting Machine) - A cutting machine with sharpened circular blades or disc-like cutters used for trimming edges and slitting sheet and foil. NOTE: cutter discs are also employed in producing circles from flat sheets but with differently designed machines.

 

Rough Machining - Machining without regard to finish, usually to be followed by a subsequent operation.

 

Rule Die Steel - A hardened and tempered medium high carbon spring steel strip sufficiently low in hardness to take moderately sharp bends without fracture, intended for manufacture into rule dies for the purpose of cutting or stamping fabrics, paper, cardboard, plastics, and metal foil into desired shape.

 

SAE - Abbreviation for Society of Automotive Engineers. This organization has specified common and alloy steels and copper base alloys in accordance with a numerical index system allowing approximation of the composition of the metal. The last two digits always indicate the carbon content, usually within 0.05%.

 

Salt Spray Test - An accelerated corrosion test in which the metal specimens are exposed to a fine mist of salt water solution either continuously or intermittently.

 

Scab (scabby) - (1) A blemish caused on a casting by eruption of gas from the mold face, or by uneven mold surfaces; or occurring where the skin from a blowhole has partly burned away and is not welded. (2) A defect consisting of a flat volume of metal joined to a casting through a small area. It is usually set in a depression, a flat side being separated from the metal of the casting proper by a thin layer of sand.

 

Scale - A layer of oxidation products formed on a metal at high temperature.

 

Scaling - (1) Oxidation of metal due to heat, resulting in relatively heavy surface layers of oxide. (2) Removal of scale from metal.

 

Scalped Extrusion Ingot - A cast, solid, or hollow extrusion ingot which has been machined on the outside surface.

 

Scalping - Machining the surface layers from ingots, billets and slabs before fabrication.

 

Scarf Joint - A butt joint in which the plane of the joint is inclined with respect to the main axes of the members.

 

Scarfing - Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface defects to be cut from ingots, billets, or the edges of plate that is to be beveled for butt welding.

 

Scleroscope Hardness (Test) - A method for measuring the hardness of metals; a diamond-pointed hammer drops from a fixed distance through a tube onto the smoothed metal surface and the rebound measured. The Scleroscope hardness value is empirically taken from the rebound distance, with a specified high-carbon steel as 100.

Scrap - Material unsuitable for direct use but usable for reprocessing by re-melting.

 

Scratch Brushed Finish - Finish obtained by mechanically brushing the surface with wire bristle brushes, by buffing with greaseless compound or by cold rolling with wire bristled rolls on scratch etched finish.

 

Seam (A defect.) - On the surface of metal a crack that has been closed but not welded; usually produced by some defect either in casting or in working, such as blowholes that have become oxidized or folds and laps that have been formed during working. Similar to cold shut and laminations.

 

Seam Annealing - The process of heating the seam weld at the Pipe Mill to improve strength.

 

Seam Welding - An electric-resistance type of welding process, in which the lapped sheet is passed between electrodes of the roller type while a series of overlapping spot welds is made by the intermittent application of electric current.

 

Secondary Hardening - Tempering certain alloy steels at certain temperatures so that the resulting hardness is greater than that obtained by tempering the same steel at some lower temperature for the same time.

 

Seconds - The designation given to sheet or strip that has imperfections in moderate degree or extent, which may be classified in two general groups -- imperfections in the base material, or other manufacturing defects. This term not used in connection with non-ferrous alloys.

 

Segment Steel - Used for laminated piston rings. Carbon content about .60%. Hardened and blue tempered with round edges. Hardness usually Rockwell’s 30 N 68 to 71, widths vary from .058 to .163 and thicknesses are .020, .024 and .030.

 

Segregation - In an alloy, concentration of alloying elements at specific regions, usually as a result of the primary crystallization of one phase with the subsequent concentration of other elements in the remaining liquid.

 

Segregation Banding - In homogeneous distribution of alloying elements aligned on filaments or plates parallel to the direction of working.

 

Self Diffusion - The spontaneous movement of an atom to a new site in a crystal of its own species.

 

Self-Hardening Steel - A steel containing sufficient carbon or alloying element, or both, to form martensite either through air hardening or, as in welding and induction hardening, through rapid removal of heat from a locally heated portion by conduction into the surrounding cold metal.

 

Semi-Steel - Cast iron (not steel) of high quality, obtained by using a large percentage of steel scrap with the pig iron.

 

Semifinished Steel - Steel in the form of billets, blooms, requiring further working before completion into finished steel ready for marketing.

 

Semikilled Steel - Steel that is incompletely deoxidized and contains sufficient dissolved oxygen to react with the carbon to form carbon monoxide and thus offset solidification shrinkage.

 

Sendzimir Mill - A mill having two work rolls of 1 to 2 1/2-in diameter each, backed up by two rolls twice that diameter and each of these backed up by bearings on a shaft mounted eccentrically so that rotating it increases the pressure between bearings and backup rolls.

 

Shear - A type of cutting operation in which the metal object is cut by means of a moving blade and fixed edge or by a pair of moving blades that may be either flat or curved.

 

Shear Bands (deformation) - Bands in which deformation has been concentrated unhomogeneously in sheets

that extend across regional groups of grains. Usually only one system is present in each regional group of grains, different systems being present in adjoining groups. The bands are non-crystallographic and form on planes of maximum shear stress (55(degrees) to the compression direction). They carry most of the deformation at large strains. Compare microbands.

 

Shear Crack - A diagonal, transgranular crack caused by shear stresses.

 

Shear Steel - Steel produced by forge welding together several bars of blister steel, providing a more homogeneous product.

 

Shear Strength - The stress required to produce fracture in the plane of cross section, the conditions of loading being such that the directions of force and of resistance are parallel and opposite although their paths are offset a specified minimum amount.

 

Sheet - A flat-rolled metal product of some maximum thickness and minimum width arbitrarily dependent on the type of metal. Sheet is thinner than plate.

 

Shell Molding - Forming a mold from thermosetting resin-bonded sand mixtures brought in contact with

preheated (300 to 500 (degrees) F) metal patterns, resulting in a firm shell with a cavity corresponding to the outline of the pattern. Also called Croning process.

 

Shielded-Arc Welding - Arc welding in which the arc and the weld metal are protected by a gaseous atmosphere, the products of decomposition of the electrode covering, or a blanket of fusible flux.

 

Shim - A thin flat hard metal strip produced to close tolerances; used primarily for tool, die and machine alignment purposes. In steel there are four general types: (1) Low Carbon Rockwell B 80/100; (2) Hard Rolled High Carbon Rockwell C 28/33. (3) Hardened and Tempered Spring Steel Rockwell C 44/51; (4) Austenitic Stainless Steel Rockwell C 35/45. Brass shim of commercial quality is also used and most generally specified is 2 Nos. Hard but may be 4 Nos. Hard.

 

Shore Hardness Test - Same as Scleroscope test.

 

Short - Brittle.

 

Short Terne - A term applying to terne coated (Lead and Tin) sheets with reference to Base Box sizes (14 x 20) Refer to terne plate.

 

Shortness - A form of brittleness in metal. It is designed as cold, hot, and red, to indicate the temperature range in which the brittleness occurs.

 

Shot Blasting - Cleaning surface of metal by air blast, using metal as a result of solidification shrinkage and the progressive freezing of metal towards the center.

 

Shrinkage Cavity - A void left in cast metals as a result of solidification shrinkage and the progressive freezing of metal towards the center.

 

Side Trimming - This is when the sides of the strip are continually being sheared off while the strip is being pulled into two vertical overlapping knives.

 

Silicon Si

Atomic Number: 14

Atomic Weight: 28.0855

Melting Point: 1687 K (1414°C or 2577°F) Boiling Point: 3538 K (3265°C or 5909°F) Density: 2.3296 grams per cubic centimeter Phase at Room Temperature: Solid

Extremely common element, the major component of all rocks and sands; its chemical reactions, however, are those of a metalloid. Used in metallurgy as a deoxidizing scavenger. Silicon is present, to some extent, in all steels, and is deliberately added to the extent of approximately 4% for electric sheets, extensively used in alternating current magnetic circuits. Silicon cannot be electrodeposited. It is one of the principal deoxidizers with the amount used dependent on the deoxidization practice. It slightly increases the strength of ferrite without a serious loss of ductility. In larger quantities, it aids the resistance to scaling up to 500°F in air and decreases magnetic hysteretic loss.

 

Silicon Steel - Steel usually made in the basic open-hearth or electric furnace, with about 0.50-5.% silicon, other elements being usually dept as low as possible. Because of high electrical resistance and low hysteretic loss, silicon sheet and strip are standard in electric magnet manufacture.

 

Siliconizing - Diffusing silicon into solid metal, usually steel, at an elevated temperature.

 

Silky Fracture - A steel fracture that has a very smooth fine grain or silky appearance.

 

Silver Solders - Alloys of silver, copper, zinc and other metals, melting between 650 and 875 (degrees) C. used for making strong yet moderately ductile joints that resist corrosion.

 

Single-Action Press - A forming press that operates with a single function, such as moving a punch into a die with no simultaneous action for holding down the bland or ejecting the formed work.

 

Sinker Steel - Used for making sinkers in hosiery making machinery. Supplied both hardened and tempered and cold rolled and annealed. Usually extra precision rolled and extra flat. Carbon content about 1.25.

 

Sinkhead or Hot Top - A reservoir insulated to retain heat and to hold excess molten metal on top of an ingot mold, in order to feed the shrinkage of the ingot. Also called shrink head or feeder head.

 

Sintered Carbide - Composite, containing carbides of extremely refractory metals, such as tungsten, tantalum, titanium, etc., cemented together by a relatively low-melting metal, such as cobalt acing as a matrix.

 

Sintering - Converting powder into a continuous mass by heating to a temperature considerably below fusion, usually after preliminary compacting by pressure. Bonding of adjacent surfaces of particles in a mass of metal powders, or in a compact, by heating

 

Skelp - A plate of steel or wrought iron from which pipe or tubing is made by rolling the skelp into shape longitudinally and welding or riveting the edges together. A piece or strip of metal produced to a suitable thickness, width, and edge configuration, from which pipe or tubing is made.

 

Skin - A thin surface layer that is different from the main mass of a metal object, in composition, structure or other characteristics.

 

Skin Pass Rolling - A light cold rolling operation that is employed to improve flatness, produce the final surface finish or texture, develop mechanical properties, and/or reduce the tendency of stretcher strain or fluting during forming.

 

Skull - A layer of solidified metal or dross on the wall of a pouring vessel often when metal has been poured.

 

Slab - A piece of metal, intermediate between ingot and plate, at least twice as wide as it is thick.

 

Slack Quenching - The process of hardening steel by quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel, resulting in incomplete hardening and the formation of one or more transformation products in addition to or instead of martensite.

 

Slag - A product resulting from the action of a flux on the nonmetallic constituents of a processed ore, or on the oxidized metallic constituents that are undesirable. Usually slags consist of combinations of acid oxides with basic oxides, and neutral oxides are added to aid fusibility.

 

Slip - Plastic deformation by irreversible shear displacement of one part of a crystal relative to another in a definite crystallographic direction and on a definite crystallographic plane.

 

Slip Direction - The crystallographic direction in which translation of slip takes place.

 

Slip Line - Trace of a slip plane on a viewing surface.

 

Slip Plane - The crystallographic plane on which slip occurs in a crystal.

 

Slit Edges - The edges of sheet or strip metal resulting from cutting to width by rotary slitters.

 

Slitting - Cutting sheet or strip metal to width by rotary slitters.

 

Slitter - A processing unit that is used for side trimming or slitting into multiples (mults).

 

Sliver (defect) - Loose metal piece rolled down onto the surface of the metal during the rolling operations.

 

Soaking - Prolonged heating of a metal at selected temperature.

 

Soft Skin Rolled Temper (No. 4 Temper) - In low carbon-rolled strip steel, soft and ductile. Produced by subjecting annealed strip to a pinch pass or skin rolling (a very light rolling).

 

Solder Embrittlement - Reduction in ductility of a metal or alloy, associated with local penetration by molten solder along grain boundaries.

 

Soldering - Joining metals by fusion of alloys that have relatively low melting points -- most commonly, lead-base or tin-base alloys, which are the soft solders. Hard solders are alloys that have silver, copper, or nickel bases and use of these alloys with melting points higher than 800 (degrees) F. is generally termed brazing.

 

Solid Solution - (1) A single solid homogeneous crystalline phase containing two or more chemical species. (2) A solid crystalline phase containing two or more chemical species in concentrations that may vary between limits imposed by phase equilibrium.

 

Solidus - In a constitutional diagram, the locus of points representing the temperatures at which various components finish freezing on cooling or begin to melt on heating.

 

Solute - The component of either a liquid or solid solution that is present to the lesser or minor extent; the component that is dissolved in the solvent.

 

Solution Heat Treatment - Heating an alloy to a suitable temperature, holding at that temperature long enough to allow one or more constituents to enter into solid solution, and then cooling rapidly enough to hold the constituents in solution. The alloy is left in a supersaturated, unstable state, and may subsequently exhibit quench aging.

 

Solvent - The component of either a liquid or solid solution that is present to the greater or major extent; the component that dissolves the solute.

 

Solvus - In a phase or equilibrium diagram, the locus of points representing the temperature at which solid phases with various compositions coexist with other solid phases; that is, the limits of solid solubility.

 

Sorbite (obsolete) - A fine mixture of ferrite and cementite produced either by regulating the rate of cooling of steel or tempering steel after hardening. The first type is very fine pearlite difficult to resolve under the microscope; the second type is tempered martensite.  Structure of steel, resulting from the tempering of martensite. In a truly sorbitic structure, the cementite is completely dispersed in the matrix. The trend is to call this structure tempered martensite.

 

Sorbitic Pearlite - Structure of steel resulting, on cooling under the proper conditions, from the decomposition of austenite; has a fine, lamellar appearance.

 

Space Lattice (crystal) - A system of equivalent points formed by the intersections of three sets of planes parallel to pairs of principal axes; the space lattice may be thought of as formed by the corners of the unit cells.

 

Space-Centered (concerning space lattices) - Body-centered.

 

Spalling - The cracking and flaking of particles out of a surface.

 

Specific Gravity - A numerical value representing the weight of a given substance as compared with the weight of an equal volume of water, for which the specific gravity is taken as 1.0000.

 

Spectograph (X-rays) - An instrument using an extended surface -- a photographic plate or film, or a fluorescent screen -- for receiving the X-ray diffraction pattern. An optical instrument for determining the presence or concentration of minor metallic constituents in a material by indicating the presence and intensity of specific wave lengths of radiation when the material is thermally or electrically excited.

 

Spelter (Prime Western Spelter) - A low-grade of Virgin Zinc containing approximately 98% Zinc used in Galvanizing processes.

 

Speroidizing - Heating and cooling to produce a spheroidal or globular form of carbide in steel. Spheroidizing methods frequently used are: 1. Prolonged holding at a temperature just below Ae1. . 2. Heating and cooling alternately between temperatures that are just below Ae1. . 3. Heating to temperature above Ae1 or Ae3 and then cooling very slowly in the furnace or holding at a temperature just below Ae1. . 4. Cooling at a suitable rate from the minimum temperature at which all carbide is dissolved, to prevent the reformation of a carbide network, and then re-heating in accordance with methods 1 or 2 above. (Applicable to hypereutectoid steel containing a carbide network.

 

Speroidizing Annealing - A sub critical annealing treatment intended to produce spheroidization of cementite or other carbide phases.

 

Spheroidize Anneal - A special type of annealing that requires an extremely long cycle. This treatment is used to produce globular carbides and maximum softness for best machinability in some analyses, or to improve cold formability.

 

Spheroidized Structure - A microstructure consisting of a matrix containing spheroidal particles of another constituent.

 

Spheroidizing - Any process of prolonged heating and slow cooling of steel which will convey the carbide content into rounded or spheroid form.  Heating and cooling to produce a spheroidal or globular form of carbide in steel.

 

Spiegel - High-manganese pig iron, containing 15-30% manganese, approximately 5% carbon, and less than 1% silicon used in the manufacture of steel by the Bessemer, or basic open-hearth process.

 

Spinning - The procedure of making sheet metal discs into hollow shapes by pressing the metal against a rotating form (spinning chuck) by a tool.

 

Spot Welding - An electric-resistance welding process in which the fusion is limited to a small area. The pieces being welded are pressed together between a pair of water-cooled electrodes through which an electrical current is passed during a very short interval so that fusion occurs over a small area at the interface between the pieces.

 

Spring Steel - Steel, normally of the high-carbon or alloy type, used in the manufacture of springs, lending itself to appropriate heat treatment; usually made in the open hearth or electric furnace.

 

Spring Steel Strip - Any of a number of strip steels produced for use in the manufacture of steel springs or where high tensile properties are required marketed in the annealed state, hard rolled or as hardened and tempered strip.

 

Spring Temper - In brass mill terminology, Spring Temper is eight numbers hard or 60.50% reduction.

 

Spring-Back - An indicator of elastic stresses, frequently measured as the increase in diameter of a curved strip after removing it from the mandrel about which it was held. The measurement is employed as an indicator of the extent of recovery or relief of residual stresses that has been achieved by the transformation of elastic strain to plastic strain during heating or stress relieving.

 

Stabilizing Anneal - A treatment applied to austenitic stainless steels that contain titanium or columbium. This treatment consists of heating to a temperature below that of a full anneal in order to precipitate the maximum amount of carbon at titanium carbide or columbium carbide. This eliminates precipitation at lower temperatures, which might reduce the resistance of the steel to corrosion.

 

Stablizing Treatment - Any treatment intended to stabilize the structure of an alloy of the dimensions of a part. (1) Heating austenitic stainless steels that contain titanium, columbium, or tantalum to a suitable temperature below that of a full anneal in order to inactivate the maximum amount of carbon by precipitation as a carbide of titanium, columbium, or tantalum. (2) Transforming retained austenite in parts made from tool steel. (3) Precipitating a constituent from a nonferrous solid solution to improve the workability, to decrease the tendency of certain alloys to age harden at room temperature, or to obtain dimensional stability.

 

Stainless Steel - Corrosion resistant steel of a wide variety, but always containing a high percentage of chromium. These are highly resistant to corrosion attack by organic acids, weak mineral acids, atmospheric oxidation, etc.

 

Stamping - A term used to refer to various press forming operations in coining, embossing, blanking, and pressing.

 

Standard Gold - A legally adopted alloy for coinage of gold. In the United States the alloy contains 10% Cu.

 

Steel - An iron-base alloy, malleable in some temperature range as initially cast, containing manganese, usually carbon, and often other alloying elements. In carbon steel and low-alloy steel, the maximum carbon is about 2.0%; in high-alloy steel, about 2.5%. The dividing line between low-alloy and high-alloy steels is generally regarded as being at about 5% metallic alloying elements. Steel is to be differentiated from two general classes of irons: the cast irons, on the high-carbon side, and the relatively pure irons such as ingot iron, carbonyl iron, and electrolytic iron, on the low-carbon side. In some steels containing extremely low carbon, the manganese content is the principal differentiating factor, steel usually containing at least 0.25%; ingot iron contains considerably less.

 

Steel Strip - A hardened and tempered spring steel strip, usually blued, produced from approximately .85 carbon coiled rolled spring steel strip specially selected for straightness and good edges. Sometimes hand straightened or straightened by grinding and cut to desired lengths. This product is used in the printing trade as a blade to uniformly remove excess ink ('dope') from the rolls; hence its name.

 

Sterling Silver - A silver alloy containing at least 95.2% Ag, the remainder being unspecified but usually copper.

 

Sticker - Steel sheets or strip adhering. Usually by fusion spots caused by overheating during box annealing.

 

Straight-Chrome - An iron alloy. A term indicating a group of stainless steels the principal alloying element of which is chromium in varying amounts from 4.00 to 27.00%.

 

Strain - A measure of the change in the size or shape of a body, referred to its original size or shape. Linear strain is the change per unit length of a linear dimension. True strain (or natural strain) is the natural logarithm of the ratio of the length at the moment of observation to the original gauge length. Conventional strain is the linear strain referred to the original gauge length. Shearing strain (or shear strain) is the change in angle (expressed in radians) between two lines originally at right angles. When the term strain is used alone it usually refers to the linear strain in the direction of the applied stress.

 

Strain Aging - Aging induced by cold working.

 

Strain Hardening - An increase in hardness and strength caused by plastic deformation at temperatures below the recrystallization range.

 

Strand Casting (Continuous Casting) - Operation in which a cast shape is continuously drawn through the bottom of the mold as it solidifies. The length is not determined by mold dimensions.

 

Stress - Force per unit area, often thought of as force acting through a small area within a plane. It can be divided into components, normal and parallel to the plane, called normal stress and shear stress, receptively. True stress denotes the stress where force and area are measured at the same time. Conventional stress, as applied to tension and compression tests, is force decided by the original gauge length. Shearing strain (or shear strain) is the change in angle (expressed in radians) between two lines originally at right angles. When the term strain is used alone it usually refers to the linear strain in the direction of the applied stress.

 

Stress Relief - Low temperature annealing for removing internal stresses, such as those resulting on a metal from work hardening or quenching.

 

Stress Relieving - Heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling slowly enough to minimize the development of new residual stresses.

 

Stress Relieve Temper - A thermal treatment to restore elastic properties and to minimize distortion on subsequent machining or hardening operations. This treatment is usually applied to material that has been heat treated (quenched and tempered). Normal practice would be to heat to a temperature 100°F lower than the tempering temperatures used to establish mechanical properties and hardness. Ordinarily, no straightening is performed after the stress relieve temper.

 

Stress-Corrosion Cracking - Failure by cracking under combined action or corrosion and stress, either external (applied) or internal (residual). Cracking may be either intergranular or transgranular, depends on metal and corrosive medium.

 

Stress-Rupture Test - A tension test performed at constant temperature, the load being held at such a level as to cause rupture. Also known as creep-rupture test.

 

Stretch Forming - A process of forming panels and cowls of large curvature by stretching sheet over a form of the desired shape. This method is more rapid than hammering and beating.

 

Stretcher Leveling - Leveling where a piece of metal is gripped at each end and subjected to a stress higher than its yield strength to remove warp and distortion. Sometimes called patent leveling.

 

Stretcher Straightening - A process for straightening rod, tubing, and shapes by the application of tension at the ends of the stock. The products are elongated a definite amount to remove warpage.

 

Stretcher Strains - Elongated markings that appear on the surface of some materials when deformed just past the yield point. These markings lie approximately parallel to the direction of maximum shear stress and are the result of localized yielding Same as Luders lines.

 

Strip - A sheet of metal whose length is many times its width.

 

Strip Steel (cold rolled) - A flat cold rolled steel product (Other than Flat Wire) 23 15/16 and narrower; under

.250 in thickness, which has been cold reduced to desired decimal thickness and temper on single stand, single stand reversing, or tandem cold mills in coil form from coiled hot rolled pickled strip steel.

 

Strip Steels and Stainless Strip - No. 1 Edge-A smooth, uniform, round or square edge, either slit or filed or slit and edge rolled as specified, width tolerance ± .005'. No. 2 Edge-A natural round mill edge carried through from the hot rolled band. Has not been slit, filed, or edge rolled. Tolerances no closer than hot-rolled

strip limits. No. 3 Edge-Square, produced by slitting only. Not filed. Width tolerance close. No. 4 Edge-A round edge produced by edge rolling either from a natural mill edge or from slit edge strip. Not as perfect as No. 1 edge. Width tolerances liberal. No. 5 Edge-An approximately square edge produced by slitting and filing or slitting and rolling to remove burr. No. 6 Edge-A square edge produced by square edge rolling, generally from square edge hot-rolled occasionally from slit strip. Width tolerances and finish not as exacting as No. 1 edge.

 

Structure - The arrangement of parts; in crystals, especially, the shape and dimension of the until cell, and the number, kinds and positions of the atoms within it.

 

Sub-boundary Structure (subgrain structure) - A network of low-angle boundaries (usually with mis- orientations or less than one degree) within the main grains of a microstructure.

 

Subcritical Annealing - An annealing treatment in which a steel is heated to a temperature below the A1 temperature and then cooled slowly to room temperature.

 

Subgrain - A portion of a crystal or grain slightly different in orientation from neighboring portions of the same crystal. Generally, neighboring subgrains are separated by low-angle boundaries.

 

Substitutional Solid Solution - A solid solution in which the solvent and solute atoms are located randomly at the atom sites in the crystal structure of the solution.

 

Substrate - The layer of metal underlying a coating, regardless of whether the layer is base metal.

 

Sulfide Spheroidization - A stage of overheating in which sulfide inclusions are partly or completely spheroidized.

 

Sulfur S

Atomic Number: 16

Atomic Weight: 32.065


Melting Point: 388.36 K (115.21°C or 239.38°F) Boiling Point: 717.75 K (444.60°C or 832.28°F) Density: 2.067 grams per cubic centimeter Phase at Room Temperature: Solid

Non-metal occurring in a number of allotropic modifications, the most common being a pale-yellow brittle solid. In steel most commonly encountered as an undesired contaminant. However, it is frequently deliberately added to cutting stock, to increase machinability.

 

Sulfur Print - A macrographic method of examining distribution of sulfide inclusions.

 

Sulfurized Pickle Oil - An oiled applied at the Pickle Line (on cold reduced product only) which contains a sulfur based emulsifier which enhances lubricity in cold reduction and burn off of oil in annealing.

 

Superalloy - An alloy developed for very high temperature service where relatively high stresses (tensile, thermal, vibratory, and shock) are encountered and where oxidation resistance is frequently required.

 

Supercooling - Cooling to a temperature below that of an equilibrium phase transformation without the transformation taking place.

 

Superficial Rockwell Hardness Test - Form of Rockwell hardness test using relatively light loads which produce minimum penetration. Used for determining surface hardness or hardness of thin sections or small parts, or where large hardness impression might be harmful.

 

Superheating - (1) Heating a phase to a temperature above that of a phase transformation without the transformation taking place. (2) Heating molten metal to a temperature to obtain more complete refining or greater fluidity.

 

Surface Hardening - A generic term covering several processes applicable to a suitable ferrous alloy that produce, by quench hardening only, a surface layer that is harder or more wear resistant than the core. There is no significant alteration of the chemical composition of the surface layer. The processes commonly used are induction hardening, flame hardening and shell hardening. Use of the applicable specific process name is preferred.

 

Tack Welds - Small scattered welds made to hold parts of a weld in proper alignment while the final welds are being made.

 

Tandem Mill - Arrangement of rolling mills, in direct line, allowing the metal to pass from one set of rolls into the next.

 

Taper Section - A section made at an acute angle to a surface of interest, thereby achieving a geometrical magnification of depth. A sectioning angle 5(degrees) 43 achieves a depth magnification of 10: 1.

 

Tapping - Transferring molten metal from melting furnace to ladle.

 

Tarnish - Surface discoloration on a metal, usually from a thin film of oxide or sulfide.

 

Teeming - Pouring molten metal from a ladle into ingot molds. The term applies particularly to the specific operation of pouring either iron or steel into ingot molds.

 

Telescoping - Transverse slipping of successive layers of a coil so that the edge of the coil is conical rather than flat.

 

TELLURIUM Te

Atomic Number: 52

Atomic Weight: 127.60

Melting Point: 722.66 K (449.51°C or 841.12°F) Boiling Point: 1261 K (988°C or 1810°F) Density: 6.232 grams per cubic centimeter Phase at Room Temperature: Solid

It is added to steel to modify sulfide type inclusion size, morphology and distribution. The resulting sulfide type inclusions are finer and remain ellipsoidal in shape following hot working, thereby improving transverse properties.

 

Temper - (1) In heat treatment, re-heating hardened steel or hardened steel or hardened cast iron to some temperature below the eutectoid temperature for the purpose of decreasing the hardness and increasing the toughness. The process also is sometimes applied to normalized steel. (2) In tool steels, temper is sometimes used, but unadvisedly, to denote the carbon content. (3) In nonferrous alloys and in some ferrous alloys (steels that cannot be hardened by heat treatment), the hardness and strength produced by mechanical or thermal treatment, or both, and characterized by a certain structure, mechanical properties, or reduction in area during cold working.

 

Temper (Met.) - The state of or condition of a metal as to its hardness or toughness produced by either thermal treatment or heat treatment and quench or cold working or a combination of same in order to bring the metal to its specified consistency. Each branch of the metal producing industry has developed its own system of temper designations. In flat-rolled products including sheet and strip steel, tin mill products, stainless strip, aluminum sheet and copper base alloy strip they are shown as follows

 

Temper Brittleness - Brittleness that results when certain steels are held within, or are cooled slowly through, a certain range of temperature below the transformation range. The brittleness is revealed by notched-bar impact tests at or below room temperature. A reversible increase in the ductile-brittle transition temperature in steels heated in, or slowly cooled through, the temperature range from about 700 to 1100 F (375 to 575 C).

 

Temper Rolling - Subjecting metal sheet or strip to a slight amount of cold rolling following annealing (usually 1/2 to 1 1/2%) to forestall stretcher strains. Also termed Pinch Pass or Skin Rolled. Light cold rolling of sheet steel. The operation is performed to improve flatness, to minimize the formation of stretcher strains, and to obtain a specified hardness or temper.

 

Tempered and Polished Spring Steel Strip - 90/1.03 carbon range (Also known as clock spring steel.) This product, while similar to general description under heading of Tempered Spring Steel Strip, is manufactured and processed with great and extreme care exercised in each step of its production. Manufactured from carbon range of .90/1.03 with Rockwell range C 48/51. Clock spring quality has been ground and polished with edges dressed. It is usually supplied hard blue in color and has a wide range of uses, such as coiled and flat mechanical springs, ignition vibrator springs, springs for timing devices, springs for the electric and electronic fields, steel tapes, rules, etc.

 

Tempered Spring Steel Strip - Any medium or high carbon (excluding clock spring) strip steel of spring quality which has been hardened and tempered to meet specifications. Where specification calls for blue or straw color, same is accomplished by passing through heat prepared at proper temperature depending on color required. Blue is developed at approximately 600 (degrees) F.

 

Tempering (Also termed 'drawing.') - A process of re-heating quench-hardened or normalized steel to a temperature below the transformation range and then cooling at any rate desired. The primary purpose of tempering is to impart a degree of plasticity or toughness to the steel to alleviate the brittleness of its martensite. In heat treatment, re-heating hardened steel to some temperature below the A1 temperature for the purpose of decreasing hardness and/or increasing toughness. The process also is sometimes applied to normalized steel.

 

Tensile Strength (Also called ultimate strength) - Breaking strength of a material when subjected to a tensile (stretching) force. Usually measured by placing a standard test piece in the jaws of a tensile machine, gradually separating the jaws, and measuring the stretching force necessary to break the test piece. Tensile strength is commonly expressed as pounds (or tons) per square inch of original cross section.

 

Tension Leveling - A mechanical process in which the strip is stretched beyond its yield point by bending over small diameter rolls while under tension. The purpose is to improve the flatness of characteristics of the strip.

 

Ternary Alloy - An alloy that contains three principal elements.

 

Terne Plate - Sheet steel, coated with a lead-tin alloy. The percentage of tin is usually kept as low as possible because of its high cost; however, about 15% is normally necessary in order to obtain proper coating of the steel, since pure lead does not alloy with iron and some surface alloying is necessary for proper adhesion.

 

Texture - In a polycrystalline aggregate, the state of distribution of crystal orientations. In the usual sense, it is synonymous with preferred orientation, in which the distribution is not random.

 

Thermal Analysis - A method of studying transformations in metal by measuring the temperatures at which thermal arrests occur.

 

Thermocouple - A device for measuring temperatures by the use of two dissimilar metals in contact; the junction of these metals gives rise to a measurable electrical potential with changes in temperature.

 

Thickness Gage or Feeler Stock - A hardened and tempered, edged, ground, and polished thin section, high carbon strip steel. Usually 1/2 in width and in thicknesses from .001 to .050 manufactured to extremely close tolerances. It is used primarily for determining measurement of openings by tool and die makers, machinists, and automobile technicians. It is prepared in handy pocket size knife-like holders containing an assembly of various thicknesses. Also prepared in standard 12 lengths with rounded ends and in 10 ' and 25' coils. Universally used in the metal industry.

 

Three-Quarter Hard Temper - (A) In stainless steel strip tempers are based on a minimum tensile or yield strength. For Chromium-Nickel grades three-quarter hard temper is 175,000 T.S., 135,000 Y.S. min. (B) In Brass mill terminology, this temper is three B&S numbers hard or 29.4% thickness reduction.


Tin Sn

Atomic Number: 50

Atomic Weight: 118.710

Melting Point: 505.08 K (231.93°C or 449.47°F) Boiling Point: 2875 K (2602°C or 4715°F) Density: 7.287 grams per cubic centimeter Phase at Room Temperature: Solid

Soft silvery white metal of high malleability and ductility, but low tensile strength. Boiling point 4384 (degrees) F., yielding the longest molten-state range for any common metal; specific gravity 7.28. Principal use as a coating on steel in tin plate; also as a constituent in alloys.

 

Tin Plate Base Box - A Tin Plate Base Box is measured in terms of pounds per Base Box (112 sheets 14 x 20) a unit peculiar to the tin industry. This corresponds to its area of sheet totaling to 31.360 square inches of any gage and is applied to tin plate weighing from 55 to 275 pounds per base box. To convert to decimal thickness multiply weight per base box by .00011.

 

Tin Plating - Electroplating metal objects with tin; the object to be coated is made cathode (negative electrode) in an electrolytic bath containing a decomposable tin salt.

 

Tinning - Coating with tin, commonly either by immersion into molten tin or by electro-deposition; also by spraying.

 

Titanium Ti

Atomic Number: 22

Atomic Weight: 47.867

Melting Point: 1941 K (1668°C or 3034°F) Boiling Point: 3560 K (3287°C or 5949°F) Density: 4.5 grams per cubic centimeter Phase at Room Temperature: Solid

Bright white metal, very malleable and ductile when exceedingly pure. Its principal functions as an alloy in the making of steel. (1) Fixes carbon in inert particles (a) reduces martensitic hardness and hardenability in medium chromium steels. (b) prevents formation of austenite in high-chromium steels. (c) prevents localized depletion of chromium in stainless steel during long heating. Now finding application in its own right because of its high strength and good corrosion resistance.  It is added to boron steels because it combines with oxygen and nitrogen, thus increasing the effectiveness of boron. Titanium, as titanium nitride, also provides grain size control at elevated temperatures in micro alloy steels. In excess, titanium is detrimental to machinability and internal cleanness.

 

Tolerance Limit - The permissible deviation from the desired value.

 

Tong Hold - The portion of a forging billet, usually on one end, that is gripped by the operator's tongs. It is removed from the part at the end of the forging operation. Common to drop-hammer and press-type forging.

 

Tool Steel - Any high carbon or alloy steel capable of being suitably tempered for use in the manufacture of tools.

 

Torsion - A twisting action resulting in shear stresses and strains.

 

Toughness - Property of resisting fracture or distortion. Usually measured by impact test, high impact values indicating high toughness. Capacity of a metal to absorb energy and deform plastically before fracturing. Ability of a metal to absorb energy and deform plastically before fracturing. It is usually measured by the energy absorbed in a notch impact test, but the area under the stress-strain curve in tensile testing is also a measure of toughness.

 

Trace - Extremely small quantity of an element, usually too small to determine quantitatively.

 

Transformation - A constitutional change in a solid metal, e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite.

 

Transformation Range - Temperature range over which a chemical or metallurgical change takes place.

 

Transformation Ranges (Transformation Temperature Ranges) - Those ranges of temperature within which austenite forms during heating and transforms during cooling. The two ranges are distinct, sometimes overlapping but never coinciding. The limiting temperatures of the ranges depend on the composition of the alloy and on the rate of change of temperature, particularly during cooling.

 

Transformation Temperature - (1) An arbitrarily defined temperature within the temperature range in which metal fracture characteristics determined usually by notched tests are changing rapidly such as from primarily fibrous (shear) to primarily crystalline (cleavage) fracture. Commonly used definitions are transition temperature for 50% cleavage fracture, 10-ft-lb transition temperature, and transition temperature for half maximum energy. (2) Sometimes also used to denote the arbitrarily defined temperature in a range in which the ductility changes rapidly with temperature.The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range. The following symbols are used for iron and steels: . Ac (cm) In hypereutectoid steel, the temperature at which the solution of cementite in austentite is completed during heating. . Ac1 The temperature at which austenite begins to form during heating. . Ac3 The temperature at which transformation of ferrite to austenite is completed during heating. . Ac4 The temperature at which austenite transforms to delta ferrite during heating. . Ae (cm) Ae1 Ae3 Ae4 The temperatures of phase changes at equilibrium. . Ar (cm) In hypereutectoid steel, the temperature at which precipitation of cementite starts during cooling. . Ar1 The temperature at which transformation of austenite to ferrite or to ferrite plus cementite is completed during cooling. Ar3 The temperature at which austenite begins to transform to ferrite during cooling. . Ar4 The temperature at which delta ferrite transforms to austenite during cooling. . M(s) (or Ar) The temperature at which transformation of austenite to martensite starts during cooling. . M(f) The temperature at which martensite formation finishes during cooling. . NOTE: All these changes except the formation of martensite occur at lower temperatures during cooling than during heating, and depend on the rate of change of temperature.

 

Transverse - Literally, 'across', usually signifying a direction or plane perpendicular to the direction of working.

 

Trepanning - A type of boring where an annular cut is made into a solid material with the coincidental formation of a plug or solid cylinder.

 

Triple Point - The intersection of the boundaries of three adjoining grains, as observed in a section.

 

Troosite (obsolete) - A previously irresolvable rapidly etching fine aggregate of carbide and ferrite produced either by tempering martensite at low temperature or by quenching a steel at a rate slower than the critical cooling rate. Preferred terminology for the first product is tempered martensite; for the latter, fine pearlite.

 

Trowel Steel - Hardened and tempered spring steel. .90 to 1.05 carbon content. Ordinary tolerances, but rolled extra flat -- Rockwell C 50. Used in the manufacture of plastering trowels.

 

Truss Spring Steel - Supplied cold rolled and bright annealed. Carbon content about .70 -- Manganese .74. Must be formed very severely and must be as free as possible from decarburization.

 

Tukon Hardness Test - A method for determining micro hardness by using a Knoop diamond indenter or Vickers square-base pyramid indenter.

 

Tumbling - Cleaning articles by rotating them in a cylinder with cleaning materials.

 

Tungsten W

Atomic Number: 74

Atomic Weight: 183.84

Melting Point: 3695 K (3422°C or 6192°F) Boiling Point: 5828 K (5555°C or 10031°F) Density: 19.3 grams per cubic centimeter

Phase at Room Temperature: Solid

Gray metal of high tensile strength, ductile and malleable when specially handled. It is immune to atmospheric influences and most acids, but not to strong alkalis. The metal is used as filament and in thin sheet form in incandescent bulbs and radio tubes. (1) Forms hard abrasion -- resistant particles in tool steels. (2) Promotes hardness and strength at elevated temperatures.

 

Tungsten Carbide - Compound of tungsten and carbon, of composition varying between WC and W(2)C; imbedded in a matrix of soft metal, such as cobalt, extensively used for Sintered Carbide Tools.

 

Twin - Two portions of a crystal having a definite orientation relationship; one may be regarded as the parent, the other as the twin. The orientation of the twin is either a mirror image of the orientation of the parent across a twinning plane or an orientation that can be derived by rotating the twin portion about a twinning axis.

 

Twin, Annealing - A twin produced as the result of heat treatment.

 

Twin, Crystal - A portion of a crystal in which the lattice is a mirror image of the lattice of the remainder of the crystal.

 

Twin, Deformation - A twinned region produced by a shear like distortion of the parent crystal structure during deformation. In ferrite, deformation twins form on {211} planes.

 

Twist - A winding departure from flatness.

 

Ultimate Strength - The maximum conventional stress, tensile, compressive, or shear, that a material can withstand.

 

Ultrasonic Frequency - A frequency, associated with elastic waves, that is greater than the highest audible frequency, generally regarded as being higher than 15 kc per sec.

 

Ultrasonic Waves - Waves of ultrasonic frequency. They include longitudinal, transverse, surface, and standing waves.

 

Universal Mill - A rolling mill in which rolls with a vertical axis roll the edges of the metal stock between some of the passes through the horizontal rolls.

 

Upset - (1) The localized increase in cross-sectional area resulting from the application of pressure during mechanical fabrication or welding. (2) That portion of welding cycle during which the cross-sectional area is increased by the application of pressure.

 

Upsetting - (1) A metal working operation similar to forging. (2) The process of axial flow under axial compression of metal, as in forming heads on rivets by flattening the end of wire.

 

Ultrasonic Testing (UT) - A type of non-destructive testing used for testing of pipe.

 

Utility Sheet Aluminum - Mill finish coiled or flat sheet of unspecified composition and properties produced in specific standard sizes and suitable for general building trade usage.

 

Vacancy - A type of structural imperfection in which an individual atom site is temporarily unoccupied.

 

Vacuum Melting - Melting in a vacuum to prevent contamination from air, as well as to remove gases already dissolved in the metal; the solidification may also be carried out in a vacuum or at low pressure.

 

Vanadium V

Atomic Number: 23

Atomic Weight: 50.9415

Melting Point: 2183 K (1910°C or 3470°F) Boiling Point: 3680 K (3407°C or 6165°F) Density: 6.0 grams per cubic centimeter Phase at Room Temperature: Solid

Gray-white, hard metal, unaffected by atmospheric influences or alkalis but soluble in most strong acids. It cannot be electrodeposited. Its principal functions as an alloy in the making of tool steels. (1) Elevates coarsening temperature of austenite (promotes fine grain). (2) Increases hardenability (when dissolved) (3) Resists tempering and causes marked secondary hardening. inhibits grain growth during heat treating while improving strength and toughness of hardened and tempered steels. Additions up to .05% increase hardenability whereas larger amounts tend to reduce hardenability because of carbide formation. Vanadium is also utilized in ferrite/pearlite micro alloy steels to increase hardness through carbonitride precipitation strengthening of the matrix.

 

Veining - A type of sub-boundary structure that can be delineated because of the presence of a greater-than- average concentration of precipitate or solute atoms.

 

Vibrator Reed Steel - Hardened, tempered and white polished extra precision rolled. Carbon content about 1.00. Steel must withstand great fatigue stresses.

 

Vickers Hardness (Test) - Standard method for measuring the hardness of metals, particularly those with extremely hard surfaces; the surface is subjected to a standard pressure for a standard length of time by means of a pyramid shaped diamond. The diagonal of the resulting indention is measured under a microscope and the Vickers Hardness value read from a conversion table.

 

Virgin Metal - Metal obtained directly from ore and not used before.

 

Waloon Process - An early two-hearth process for making wrought iron by refining cast iron. The conversion proper was carried out in a hearth furnace known as a finery; re-heating for forging was carried out in a second hearth furnace known as a chafery.

 

Wasters - Sheets that have prohibitive defects, for example, seams and buckled plates. Generally fit for re-melting purposes only.

 

Watch Main Spring Steel - Usually supplied cold rolled and annealed in large widths and cut and hardened by the spring manufacturers. Carbon content about 1.15 and Tungsten .17, extra precision rolled.

 

Water Hardening - Process of hardening high carbon steels by quenching in water or brine, after heating.

 

Wavy - Not flat. A slight wave following the direction of rolling and beyond the standard limitation for flatness.

 

Wedge - A hardwood stick used as a forming tool in spinning.

 

Weld - A union made by welding.

 

Weld Bead - A deposit of filler metal from a single welding pass.

 

Weldability - Suitability of a metal for welding under specific conditions.

 

Welding - A process used to join metals by the application of heat. Fusion welding, which includes gas, arc, and resistance welding, requires that the parent metals be melted. This distinguishes fusion welding from brazing. In pressure welding joining is accomplished by the use of heat and pressure without melting. The parts that are being welded are pressed together and heated simultaneously, so that recrystallization occurs across the interface.

 

Wetting - A phenomenon involving a solid and a liquid in such intimate contact that the adhesive force between

the two phases is greater than the cohesive force within the liquid. Thus a solid that is wetted, on being removed from the liquid bath, will have a thin continuous layer of liquid adhering to it. Foreign substances such as grease may prevent wetting. Addition agents, such as detergents, may induce wetting by lowering the surface tension of the liquid.

 

Wetting Agent - A surface-active agent that produces wetting by decreasing the cohesion within the liquid.

 

Widmanstatten Structure - A structure characterized by a geometrical pattern resulting from the formation of a new phase along certain crystallographic planes of the parent solid solution. The orientation of the lattice in the new phase is related crystallographically to the orientation of the lattice in the parent phase. The structure was originally observed in meteorites but is readily produced in many other alloys with certain heat treatment.

 

WMB, WHB and Extra WHB Grades - Spring steel wires produced from aced open-hearth steels.

 

Wootz - A carbon steel containing 1 to 1.6% C produced by melting a bloomery iron or an inhomogeneous steel with charcoal in a crucible. The process originated in India as early as the 3rd century A.D.

 

Work Hardening - Increase in resistance to deformation (i.e. in hardness) produced by cold working. Same as strain hardening.

 

Workability - The characteristic or group of characteristics that determines the ease of forming a metal into desired shapes.

 

Wrought Iron - Iron containing only a very small amount of other elements, but containing 1-3% by weight of slag in the form of particles elongated in one direction, giving the iron a characteristic grain. Is more rust-resistant than steel and welds more easily. An iron produced by direct reduction of ore or by refining molten cast iron under conditions where a pasty mass of solid iron with included slag is produced. The iron has a low carbon content.

 

Wustite - The oxide of iron of lowest valence which exist over a wide range of compositions the do not quite include the stoichiometric composition FeO.

 

X-Rays - Light rays, excited usually by the impact of cathode rays on matter, which have wave lengths between about 10-6 cm, and 10-9 cm; also written X-rays, same as Roentgen rays.

 

Yellow Brass - 65% copper and 35% zinc. Also known as High Brass. A copper-zinc alloy, named for its yellow hue. Formerly a very popular alloy, but now largely replaced by Cartridge Brass.

 

Yield Point - The first stress in a material, usually less than the maximum attainable stress, at which an increase in strain occurs without an increase in stress. Only certain metals exhibit a yield point. If there is a decrease in stress after yielding, a distinction may be made between upper and lower yield points.

 

Yield Strength - The stress at which a material exhibits a specified limiting deviation from the proportionality of stress to strain. The deviation is expressed in terms of strain. Also known as proof stress.

 

Young's Modulus - The coefficient of elasticity of stretching. For a stretched wire, Young's Modulus is the ratio of the stretching force per unit cross-sectional area to the elongation per unit length. The values of Young's Modulus for metals are of the order 10(12) dynes per square cm.

Zinc Zn

Atomic Number: 30

Atomic Weight: 65.409

Melting Point: 692.68 K (419.53°C or 787.15°F) Boiling Point: 1180 K (907°C or 1665°F) Density: 7.134 grams per cubic centimeter

Phase at Room Temperature: Solid

Blue-white metal; when pure, malleable and ductile even at ordinary temperatures. Can be electrodeposited; it is extensively used as a coating for steel and sheet zinc finds many outlets, such as dry batteries, etc. Zinc-base alloys are of great importance in die casting. Its most important alloy is brass.

 

ZIRCONIUM Zr

Atomic Number: 40

Atomic Weight: 91.224

Melting Point: 2128 K (1855°C or 3371°F) Boiling Point: 4682 K (4409°C or 7968°F) Density: 6.52 grams per cubic centimeter Phase at Room Temperature: Solid

Because of its great affinity for oxygen and combines readily with nitrogen and sulfur it is used as a deoxidizer and scavenger in steel making. It is used as an alloy with nickel for cutting tools and is used in copper alloys.


 

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