A – D
Abrasion
The process of rubbing, grinding, or wearing away by friction.
Abrasion Resistance
The ability of a metal to withstand surface wear.
Abrasive
A substance capable of grinding away another material.
Abrasive Sawing
A method for making straight line cuts on any metals although it is normally used for stainless and nickel alloys.
Accelerated Corrosion Test
A test conducted under controlled condition that is considerably more severe than those natural conditions whose effects are presumably being investigated. The advantage of such a test is the relatively short time required. Results are useful for qualitative comparisons, but are not reliable for predicting anticipated life in actual service.
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.
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-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.
Additions
Elements or alloys that are added to the molten bath of steel, either in the furnace or in the ladle, to produce the composition required for the specified steel.
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 Frame Tubing
Tubing produced for aircraft structural parts. It is made to special surface quality, mechanical properties and other characteristics required by Military Specifications (MIL-T) and SAE Aeronautical Materials Specifications (AMS).
Aircraft Quality
Denotes material for important or highly stressed parts of aircraft and for other similar purposes; such materials are of extremely high quality requiring closely controlled, restrictive and special practices in their manufacture. Synonymous with Magnaflux Quality.
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 ar 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.
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.
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.
Alodizing
A proprietary term that applies to the application of an Amchem Products solution known as Alodize merely one of several types of conversion coatings. Alodizing is included here because it is often confused with a very different process Anodizing.
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 (Chemical symbol Al)
Element No. 13 of the periodic system; Atomic weight 26.97; silvery white metal of valence 3; melting point 1220 (degrees) F; boiling point approximately 4118 (degrees) F.; 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 Killed Steel
A steel where aluminum has been used as a deoxidizing agent.
AMS
Aerospace Material Specifications are written by the SAE (Society of Automotive Engineers). These specifications cover all types of materials used in the aerospace industry.
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
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, malleablizing, process annealing, quench annealing, recrystallization annealing, and spheroidizing. 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.
Annealing Twin
A twin formed in a metal during an annealing heat treatment.
Anodizing (Aluminum Adic 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 dye colored coatings are possible by impregnation in process.
ANSI
American National Standards Institute Adopts ASTM specifications as American National Standards.
AOD (Argon Oxygen Decarburization)
This term refers to both the process and the vessel that is used for the process in which hot metal from an electric furnace is refined to a chemical specification by blowing a mixture of gases (a combination of inert gas and oxygen) under the hot metal surface. The result removes carbon from the hot metal and produces steel by adding alloying elements (raw materials) in the form of ferroalloys to achieve a certain chemical specification. The economics of this process have indicated that this method is ideally suited for producing stainless, plus high and low alloy steels.
API
American Petroleum Institute Through its standardization committees, writes and publishes specifications. Some of these specifications reference ASTM specifications and directly or indirectly involve plates. Authorized manufacturers may use the API monogram.
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.
ASM
American Society for Metals International.
ASME
American Society of Mechanical Engineers- Adopts specifications prepared by ASTM. The adopted specifications are those approved for use under the ASME Boiler and Pressure Code and are published by ASME in Section II of the ASME Code. The ASME specifications have the letter S preceding the A of the ASTM specification designation.
ASTM
Abbreviation for American Society For Testing Material. An organization for issuing standard specifications on materials, including metals and alloys.
As Drawn
Bar, tubing, shape, etc is not thermally treated after cold drawing.
As-Welded Cold Rolled Tubing
Used for applications where superior surface is required, as for plating. Has slightly closer wall and inside diameter tolerances in most sizes.
As-Welded Hot Rolled Tubing
Most economical for many applications where surface finish and/or inside diameter tolerances are not as critical. May be specified with inside flash in, flash controlled to .010 max., or flash controlled to .005 max.
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 (Austenite)
Austenite is a crystal structure of the metal where the grains are closely stacked on one another and can slide easily. Therefore, this structure has great ductility. In martensitic stainless steels, heating above the critical temperature range causes a transformation to austenite. Fast cooling by quenching then transforms the austenite to martensite.
Ausenitic 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
Phase in certain steels, characterized as a solid solution, usually of carbon or iron carbide, in the hamma form of iron. 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 austenitec 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).
Austentite
A solid solution of one or more elements in face-centered cubic iron.
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.
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 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.
Bar
A solid section of metal that is long in relation to its cross section, which is square, rectangular (excluding plate) or is a regular hexagon or octagon and in which at least one perpendicular distance between parallel faces is 0.375 inches or greater.
Bar Mill
Rolling mill where semi-finished billets are processed into HR bars.
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.
Basic Oxygen Furnace (BOF)
This term describes the process and the vessel that is used in the process by which hot metal, received from the induction furnace, is refined to meet chemical specifications by blowing oxygen from a top lance against the hot metal bath surface. This reduces the carbon level to an acceptable level and raw materials are added to achieve a desired chemical specification.
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 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.
Batch or Press Break Process
This process is used for steel plate and large diameter pipe. The products are formed on a hydraulic press break and placed on a weld mill where they are sized and welded. This process is very slow.
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 Quality (BQ)
Metal designed as bearing quality has been tested for imperfections to make it suitable for critical applications like anti-friction bearings.
Bearing Strength
The maximum bearing load at failure divided by the effective bearing area. In a pinned or riveted joint, the iffective area is calculated as the product of the diameter of the hole and the thickness of the bearing member.
Bend Radius (Recommended minimum)
A rule of thumb type of measurement of a materials ability to adapt to bending to a 90 degree inside angle using a vee press brake die. Taking into consideration a particular metals mechanical properties and its thickness, the bend radius charts will serve to tell how sharp a bend can be made in metal without it fracturing on the outside of the bend. These charts set down recommended minimum inside bend radii. It is suggested that one fabricate to an inside radius slightly larger than the one specified. It is important that the fabricator realize that the bend radius charts are valid only if the forming is classified as an air bend and the metal does not bottom in the die.
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.
Bevel
An angular cut on the I.D. or O.D. of a tube end.
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.
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 (Scaleless 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 light weight or a thin uncoated steel sheet or strip so called because of its dark oxide coloring prior to pickling. It is manufactured by two different processes. (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 pih 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.
Bloom
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. Iron and steel blooms are sometimes made by forging.
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.
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.
Blue Brittleness
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 ( chemical symbol B)
Element N. 5 of the periodic system. Atomic weight 10.82. 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.
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.
Box Annealing
A process of annealing a ferrous alloy in a closed metal container, with or without packing materials, in order to minimize the effects of oxidation. The charge is normally heated slowly to a temperature below the transformation range, but occasionally above or within it, and then is slowly cooled.
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.
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.
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. The diameter of the indentation, in the material surface, is then measured by a microscope 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 refered 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.
B.T.U.
British Thermal Unit
Buckle
Bulges and/ or hollows occurring along the length of the metal with the edges remaining otherwise flat.
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.
Burning
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.
Bushing
A cylindrical lining for an opening used to limit the size of the opening to resist abrasion, or to serve as a guide.
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
Joining two edges or ends by placing one against the other and welding them.
Cake
A copper ingot rectangular in cross section intended for rolling.
Cam
A rotating or sliding piece that imparts motion to a roller moving against its edge or to a pin free to move in a groove on its face.
Camber
(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.
Camber or Bow
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.
Carbide Precipitation
The phenomenon of carbides coming out of a solid solution, occurring in stainless steel when heated into the range of 800-1600 degrees Fahrenheit.
Carbon
Chemical symbol C. Element No. 6 of the periodic system; atomic weight 12.01; 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.
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
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.
Carbon Steel
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 hydrocardons, carbon monocide, and ammonia. The carbonitrided alloy is usually quench hardened.
Carbonitriding.
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
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.
Carburizing
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.
Carburizing (Cementation)
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
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.
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.
Cast Steel
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.
Caustic Etch
Like the bright dip, caustic etch is a pretreatment for anodizing. The anodic film is transparent and exposes the as-received surface of the aluminum that may not be pleasing to the eye. By subjecting the bare, clean aluminum to a caustic bath, the surface of the metal will be minutely eaten away and leveled. The resulting soft frosted, or matte, appearance is consistently attractive under the anodic film.
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.
Centerless Grinding
Grinding the surface of a bar that is supported by rollers rather than on centers.
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.
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
An uneven surface on a machined part, caused by vibration of the tool, work, or machine during machining.
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.
Chem Mill Sheet
Heat treated sheet which has been stretched a minimum of 1% to improve stability in operations like chem milling.
Chemical Polishing
Improving the specular reflectivity of a metal surface by chemical treatment.
Chemistry
Elements in stainless steel by percent of weight.
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.
Chloride
This term is used generically referring to salts and other compounds that have a corrosive effect on stainless steels.
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
Chemical symbol Cr. Element No. 24 of the periodic system; atomic weight 52.01. 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).
Chromium Carbide
One of a number of compounds of chromium and carbon, with or without limited amounts of other metallic elements when occurring in steel. It appears as a separated phase in chromium steels and stainless steels.
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.
Class I Hollow Shape
A hollow extruded shape whose void is round and one inch or more in diameter, and whose weight is equally distributed.
Class II Hollow Shape
Any hollow extruded shape other than Class I, which does not exceed a 5-inch diameter circumscribing circle and has a single void of not less than .375-inch diameter of .110-square inch area.
Class III Hollow Shape
Any hollow extruded shape other than Class I or Class II.
Cleanup
The amount of metal removal required to obtain desired dimensions and complete removal of inherent surface imperfections.
Clean Up Allowance
Must be added to the finished O.D. dimension or subtracted from the finished I.D. dimension to provide for the elimination of surface imperfections.
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
Chemical symbol Co. Element No. 27 of the periodic system; atomic weight 58.94. 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 Thermal Expansion
A physical property value representing the change in length per unit length, the change in area per unit area or the change in volume per unit volume per one degree increase in temperature.
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.
Coiled Plate
A product used by plate processors to produce flat, cut-to-size plates. Decoiling, flattening and shearing equipment are employed to obtain the 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 Drawn
A hot finished bar that has been pulled through a die slightly smaller than the bar diameter.
Cold Finished
A metal product that has undergone processes such as drawing or turning at room temperature.
Cold Finishing
The cold finishing of steel may be defined as the process of reducing the cross sectional area of bars by one of the following methods (1) cold rolling; (2) cold drawing; (3) cold drawing and grinding; (4) turning and polishing; or (5) turning and grinding.
Cold finishing is employed principally for one or more of the following reasons (1) special size accuracy; (b) smooth or bright surface finish; (3) improved mechanical properties; and (4) better machinability.
Cold Reduced Strip
Metal strip, produced from hot-rolled strip, by rolling on a cold reduction mill.
Cold Reduction
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.
Cold Rolled
A flat rolled product that has undergone final reduction to finished thickness at room temperature.
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 Sawing
Metal cutting techniques in which the heat generated is dissipated in the chip and therefore there is not heat-affected zone.
Cold Short
A condition of brittleness existing in some metals at temperatures below the recrystalization temperature.
Cold Sinking
Similar to cold drawing, except that the tube is drawn through a die, but without an internal mandrel. Usually used only for making heavy wall or small tubing, where drawing over a mandrel is impractical. Only outside diameter is closely controlled.
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
Chemical symbol Cb. Element No. 41 of the periodic system. Atomic weight 92.91. It is steel gray in color and brilliant luster. Specific gravity 8.57. Melting point at about 4380 (degrees) F. 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. (Now known as Niobium (Nb), element No. 41 of the periodic system.)
Columnar Structure
A structure consisting of elongated grains whose tong axes are parallel.
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 Tubing
A term used to describe tubing that may be used as received for many applications. It is generally produced to the suppliers wall thickness, O.D. and I.D. tolerances, as well as to the suppliers mechanical properties.
Common Alloys
One of several terms used in the industry to identify the non-heat-treatable classes of alloys alloys identified in the four-digit numbering system by having their first digit as 1, 3, 5 or in some cases 8. This category of alloys has its strength levels increased by being subject to some type of cold-working processes such as rolling, drawing or stretching, but not through any of the thermal processes. Exposure to temperatures above rather low levels can only reduce the strength of the non-heat-treatable or common alloys.
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.
Concentricity
In tubular products, concentricity is the degree to which the centerline of the inside diameter (I.D.) is consistent with the centerline of the outside diameter (O.D.).
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 Annealing
The process where coils are unwound and run continuously through an annealing furnace at prescribed softening temperatures.
Continuous Casting
A casting technique in which the ingot is continuously solidified while it is being poured, and the length is not determined by mold dimensions.
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.
Continuous Weld (C.W.) or Continuous Buttweld (CBW)
In contrast to the ERW system, the steel is formed into a tubular shape while the steel is hot. The edges when they meet are fused or welded together, but no additional weld material is necessary. (For CW tubing, the tube is always further processed by cold drawing.)
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
Chemical symbol Cu) Element No. 29 of the periodic system, atomic weight 63.57. A characteristically reddish metal of bright luster, highly malleable and ductile and having high electrical and heat conductivity; melting point 1981 (degrees) F.; boiling point 4327 F.; specific gravity 8.94. Unibersally 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.
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
Deterioration of a metal by chemical or electrochemical reaction with its environment.
Corrosion Embrittlement
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.
Corrosion Resistance
The ability of a metal to withstand attack in an environment that is conducive to chemical or electrochemical reaction.
Corrosion Resistant Alloys
These are materials that provide a higher degree of corrosion. Corrosion resistant alloys are generally characterized by chrome content of at least 10%.
Corrugated
As a defect. Alternate ridges and furrows. A series of deep short waves.
Covered Electrode
A filler-metal electrode, used in arc welding, consisting of a metal core vire 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.
CPI
Chemical Process Industries, a huge market for both stainless and nickel alloys.
Creep
Time-dependent strain occurring under stress.
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 Corrosion
Occurs when there is an agent on the metal that might be as simple as a rubber band or a grease pencil that prevents oxygen from reaching the metal to re-form the passive film.
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 limiting rate at which austenite must be cooled to ensure that a particular type of transformation product is formed.
Critical Point
(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 combination of composition, temperature and pressure at which the phases of an inhomogeneous system are in equilibrium.
Critical Points
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.
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.
Cross Rolling
Rolling at an angle to the long dimension of the metal; usually done to increase width.
Crown
A contour on a sheet or roll where the thickness or diameter increases from edge to center.
Crown or Heavy Center
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.
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
A type of fracture in a tensile test specimen which looks like a cup having the exterior portion extended with the interior slightly depressed.
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.
Cut Length
Refers to tubing ordered to a specified length and permitting a tolerance of a standardized fraction of an inch over but nothing under the specified length.
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.
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 semicontinuous 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
The loss of carbon from the surface of a ferrous alloy as a result of heating in a medium that reacts with the carbon at the surface.
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.
De-Dimpling
Removal of dimple by pulling the tube back to round.
Deep Draw (High Form)
A category of annealed, heat-treatable aluminum alloy which has a controlled grain size of ASTM 6 to 10.
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 inhomogeneously.
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.
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 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.
Deoxidizing
Removal of oxygen. In steel sheet, strip, and wire technology, the term refers to heat treatment in a reducing atmosphere, to lessen the amount of scale.
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.
Dimensions
O.D. Outside diameter. Specified in inches and fractions of an inch, or inches and decimals of an inch.
I.D. Inside diameter. Specified in the same units as the O.D.
Wall Wall thickness or gage. Specified in either fractions or decimals of an inch or by a wire gage number. In the United States, the most common gage used for tubing is the Birmingham iron wire gage, designated B.W.G..
Nominal The theoretical or stated value of the O.D., I.D. or wall dimension as specified by the customer.
Maximum and Minimum The dimensions resulting after applying the proper tolerances to the nominal dimensions.
Minimum Wall Generally, the lightest wall permitted within specified tolerances. A minimum wall tube is one whose wall thickness is not permitted to fall below the specified nominal measurements.
Average Wall A tube whose wall thickness is permitted to range over or under the specified nominal wall measurement within certain defined tolerances.
Dimpling
Occurs when tubing is punch cut. A depression is formed by the cutting operation.
Direct Extruding
The extrusion process in which the die and container is held stationary and the metal forced through it by a moving ram.
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.
DOM
Drawn over Mandrel. (A cold working process)
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.
Drill Rod
A term given to an annealed and polished high carbon tool steel rod usually round and centerless 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.
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.
Ductility
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.