AIST
AIST Steel Glossary

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17-7 Term normally used for 17-7PH™1 precipitation hardenable stainless steel. However, whenever it is used by a potential customer, it should be clarified that they mean 17-7PH™1. In the past, 17-7 has been used to signify type 301 which also is 17% Chromium -7% Nickel stainless steel, but not precipitation hardenable.

A Coatings Coatings on hot dipped galvanized steels processed to convert the coating completely to zinc-iron alloys; dull gray in appearance, have no spangle, and after proper preparation, are well suited for painting.

A Elevation The top level of the boiler firebox where four oil guns are located. The oil guns are used to produce steam and maintain pressure while the boiler is on oil fire.

A/F Air/fuel ratio.

AAR Association of American Railroads.

AB Screws Sheet metal screws with pointed ends similar to Type-A screws and thread dimensions similar to Type-B. Type AB screws are seldom used in stainless.

Abrasion The displacement and/or detachment of metallic particles from a surface as a consequence of being exposed to flowing solids, fluids or gases. 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 Material for grinding, polishing, blasting, either in loose form or bonded to form wheels, bricks, or files, or applied to paper and cloth by glue or resin. Natural abrasives include emery, corundum, garnet, sand, flint, etc. Metallic shot and grit are also used as abrasives in cleaning castings.

Abrasive Natural – sandstone, emery, corundum, diamonds, or Artificial – silicon carbide, aluminum oxide – material used for making grinding wheels, and paper, abrasive and lapping compounds.

Abrasive Blasting A process for cleaning or finishing by means of an abrasive directed at high velocity against the workplace.

Abrasive Disk 1. A grinding wheel that is mounted on a steel plate, with the exposed flat side being used for grinding. 2. A disk-shaped, coated abrasive product.

Abrasive Wear The displacement and/or detachment of metallic particles from a surface as a consequence of being exposed to flowing fluids or gases.

Abrasive Wheels Wheels of a hard abrasive, such as Carborundum used for grinding.

Absolute Pressure The sum of hydraulic system pressure and gauge pressure. (see Pressure)

Absolute Temperature The temperature reckoned from the absolute zero temperature.

Absolute Viscosity Term used interchangeably with viscosity to distinguish it from kinematic viscosity and/or commercial viscosity; occasionally, dynamic viscosity.

Absorbent (Wash Oil) An oil that selectively strips heavier hydrocarbons from a gas, as in coke oven gas; byproduct plants subsequently remove the hydrocarbons.

Accelerated Corrosion Test Method designed to approximate, in a short time, the deteriorating effect obtained under normal long-term service conditions.

Accelerated Testing A test performed on materials or assemblies that is meant to produce failures caused by the same failure mechanism as expected in field operation but in significantly shorter time. The failure mechanism is accelerated by changing one or more of the controlling test parameters.

Accelerated-Life Test A method designed to approximate, in a short time, the deteriorating effect obtained under normal long-term service conditions. (see Artificial Aging)

Accelerator A substance that hastens a reaction usually acting as a catalyst; as used in sand additive resins.

Accm In hypereutectoid steel, the temperature at which cementite goes into complete solution with austenite.

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.

Accumulator (Hydraulics) A device in which hydraulic fluid is stored under pressure in a system to be used as a source of fluid power.

Acetyl Tributyl Citrate One of the lubricating oils generally applied on tin mill products (tin plate, TFS-chrome/chrome oxide coated steel, and blackplate).

Acicular Ferrite A highly substructured non-equiaxed ferrite that forms upon continuous cooling by a mixed diffusion and shear mode of transformation that begins at a temperature slightly higher than the temperature transformation range for upper bainite. It is distinguished from bainite in that it has a limited amount of carbon available; thus, there is only a small amount of carbide present.

Acicular Ferrite A highly substructured nonequiaxed ferrite formed upon continuous cooling by a mixed diffusion and shear mode of transformation that begins at a temperature slightly higher than the transformation temperature range for upper bainite. It is distinguished from bainite in that it has a limited amount of carbon available; thus, there is only a small amount of carbide present.

Acicular Ferrite Steels Ultralow-carbon (<0.08%) steels having a microstructure consisting of either acicular ferrite (low-carbon bainite) or a mixture of acicular and equiaxed ferrite.

Acid 1. A chemical substance that yields hydrogen ions (H+) when dissolved in water. Compare with base. 2. A term applied to slags, refractories and minerals containing a high percentage of silica.

Acid Bottom and Lining The inner bottom and lining of a melting furnace, consisting of materials like sand, siliceous rock or silica brick that give an acid reaction at the operating temperature.

Acid Copper 1. Copper electrodeposited from an acid solution of a copper salt, usually copper sulfate. 2. The solution referred to in 1.

Acid Embrittlement A form of hydrogen embrittlement that may be induced in some metals by acid.

Acid Number The mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance. (see Acidity) (see Strong acid/strong base numbers)

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 phosphorous pig iron is required as this element is not removed.

Acid Rain Atmospheric precipitation with a pH below 5.6 to 5.7. Burning of fossil fuels for heat and power is the major factor in the generation of oxides of nitrogen and sulfur, which are converted into nitric and sulfuric acids washed down in the rain. (see Atmospheric Corrosion)

Acid Refractory Siliceous ceramic materials of a high melting temperature, such as silica brick, used for metallurgic furnace linings. (see Basic Refractories)

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.

Acidity In lubricants, acidity denotes the presence of acid-type constituents. The concentration of acid is expressed as an acid number or neutralization number.

Acme Thread A screw thread having a 29° included angle. Used largely for feed and adjusting screws on machine tools.

Acoustic Emission Acoustic Emission A measure of integrity of a material, as determined by sound emission when a material is stressed. Ideally, emissions can be correlated with defects and/or incipient failure.

ACS American Chemical Society.

Actinide Metals The group of radioactive elements of atomic numbers 89 through 103 of the periodic system—namely, actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and lawrencium.

Activated Rosin Flux A rosin-base flux containing an additive that increases wetting by the solder.

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

Activation Energy The energy required for initiating a metallurgical reaction—for example, plastic flow, diffusion, chemical reaction. The activation energy may be calculated from the slope of the line obtained by plotting the natural log of the reaction rate versus the reciprocal of the absolute temperature.

Active The negative direction of electrode potential. Also used to describe corrosion and its associated potential range when an electrode potential is more negative than an adjacent depressed corrosion rate (passive) range.

Active Metal A metal ready to corrode or being corroded.

Activity A measure of the chemical potential of a substance, where the chemical potential is not equal to concentration, that allows mathematical relations equivalent to those for ideal systems to be used to correlate changes in an experimentally measured quantity with changes in chemical potential.

Actuator A mechanical device, like a cylinder or hydraulic motor, used to convert hydraulic energy into mechanical energy.

Acute Angle An angle that is less than 90°.

Adapter Bolt (Lube Systems) A part used to connect an injector to a manifold block.

Adapters Steel segments that are bolted to the reel mandrel to increase their diameter so that large (24" I.D.) coils can be run.

Addendum (Gears) Distance between the pitch circle and the tooth crest.

Addition Agent 1. A substance added to a solution for the purpose of altering or controlling a process. Examples: wetting agents in acid pickles; brighteners or antipitting agents in plating solutions; inhibitors. 2. Any material added to a charge of molten metal in a bath or ladle to bring the alloy to specification.

Additions Materials, typically alloy elements, added to molten steel to produce the chemical specifications for the desired steel grade.

Additive A chemical compound or compounds added to a lubricant or hydraulic fluid to impart new properties or enhance inherent properties.

Adhesion The property of a lubricant that causes it to cling or adhere to a solid surface.

Adhesive A substance capable of holding materials together by surface attachment. Adhesive is a general term and includes, among others, cement, glue, mucilage and paste.

Adhesive Bonding A materials joining process in which an adhesive, placed between the faying surface (adherends), solidifies to produce an adhesive bond.

Adhesive Wear 1. Wear by transference of material from one surface to another during relative motion due to a process of solid-phase welding. Particles that are removed from one surface are either permanently or temporarily attached to the other surface. 2. Wear due to localized bonding between contacting solid surfaces leading to material transfer between the two surfaces or loss from either surface. (see Abrasive Wear)

Adjustable Bed Bed of a press designed so that the die space height can be varied conveniently.

Adjustable or Variable Voltage A method of bridge crane control by which the motor supply voltage can be adjusted.

Adjusting Assembly (Lube Systems) A device used to control the length of the piston stroke.

Advanced Ceramics Produced with tightly controlled chemical compositions through special processing. They exhibit superior properties and reliability and often perform in severe environments and emerging applications.

Aeration Making contact between air and a liquid by spraying liquid into the air or by agitating the liquid to promote absorption of air. Also act of fluffing molding sand.

AGC System (Automatic Gauge Control) System for controlling the thickness of the product being rolled by computer control of the gap between the rolls with force and/or thickness measurement feedback loop.

Age Hardening A process of aging that increases hardness and strength and ordinarily decreases ductility. Age hardening usually follows rapid cooling or cold working.

Age Softening Spontaneous decrease of strength and hardness that takes place at room temperature in certain strain hardened alloys, especially those of aluminum.

Agglomerating Processes Fine particles of limestone (flux) and iron ore are difficult to handle and transport because of dusting and decomposition, so the powdery material usually is processed into larger pieces. The raw material's properties determine the technique that is used by mills.

Aggregate Composed of mineral fragments.

Aging A change in the properties of certain metal and alloys, (such as steel), that occurs at ambient or moderately elevated temperatures after a hot working heat treatment or cold working operation. Typical properties impacted are: hardness, yield strength, tensile strength, ductility, impact value, formability, magnetic properties, etc. (see Non-aging)

AGMA American Gear Manufacturers Association, www.agma.org.

AIChE American Institute of Chemical Engineers.

Air Acetylene Welding A fuel gas welding process in which coalescence is produced by heating with a gas flame or flames obtained from the combustion of acetylene with air, without the application of pressure and with or without the use of filler metal.

Air Bend Die Angle-forming dies in which the metal is formed without striking the bottom of the die. Metal contact is made at only three points in the cross-section: the nose of the male die and the two edges of a v-shape die opening.

Air Carbon Arc Cutting An arc cutting process in which metals to be cut are melted by the heat of a carbon arc and the molten metal is removed by a blast of air.

Air Classification The separation of metal powder into particle-size fractions by means of an air stream of controlled velocity; an application of the principle of elutriation.

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 Entrainment The presence of air bubbles throughout an oil as a result of agitation and/or the release of dissolved air because of a sudden change in environment. Air entrainment is visible, as the oil becomes opaque and bubbly. (see Foam Test)

Air Furnace Reverbatory-type furnace in which metal is melted by heat from fuel burning at one end of the hearth, passing over the bath toward the stack at the other end. Heat also is reflected from the roof and side walls.

Air Heaters Bank of boiler tubes located in the exhaust gas ductwork which preheats the incoming combustion air by transferring heat from the exhaust gases passing through them to the incoming air passing around them. Preheating the air reduces boiler fuel requirements.

Air Line Lubricator An oil reservoir attached to an air line that provides automatic airborne lubrication to air operated power consuming equipment by means of venturi action.

Air Oil Separator A mechanical device that defoams oil, using a centrifugal oil trap (a defoamer), or any oil condensing device in an air line.

Air Quenching Accelerated cooling of alloy in an air stream from temperatures above the Ac3 temperature.

Air Scale Scale left on ferrous metal in processing, usually from heating in presence of air.

Airblasting A cleaning operation, as cleaning sand from molds.

Aircraft Quality Denotes stock of sufficient quality to be forged into highly stressed parts for aircraft or other critical applications. Such materials are of extremely high quality, requiring closely controlled, restrictive practices in their manufacture in order that they may pass rigid requirements, such as magnetic particle inspection (Ref: Aerospace Material Specification 2301).

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. The term should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 inches or more in diameter.

Air-Lift Hammer A type of gravity-drop hammer in which the ram is raised for each stroke by an air cylinder. Because length of stroke can be controlled, ram velocity and therefore the energy delivered to the workpiece can be varied. (see Drop Hammer) (see Gravity Hammer)

Air-Lift Hammer A type of gravity drop hammer where the ram is raised for each stroke by an air cylinder. Because length of stroke can be controlled, ram velocity and thus energy delivered to the workpiece can be varied.

Air-Oil Lubrication A system of lubrication in which small quantities of oil are injected into an air line that terminates at a bearing or other lubrication point. The velocity of the air moves the oil, which remains in droplet form, along the periphery of the fluid conductor to the point of need; the clean, dry air, being unheated, helps cool the lubrication point. Since the lubricant does not return to a reservoir, these systems are classified as all-loss systems.

AISE Association of Iron and Steel Engineers (now AIST, Association for Iron & Steel Technology), www.aist.org.

AISE Association of Iron and Steel Engineers

AISI American Iron and Steel Institute

AISI www.steel.org. (see American Iron and Steel Institute (AISI))

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 or basic open-hearth carbon steel, E electric furnace alloy steel.

AIST Acronym: APB AIST Process Benchmarker

AIST Acronym: CATC Computer Applications Technology Committee

AIST Acronym: CMTC Cokemaking Technology Committee

AIST Acronym: CSRTC Cold Sheet Rolling Technology Committee

AIST Acronym: CTC Cranes Technology Committee

AIST Acronym: EATC Electrical Applications Technology Committee

AIST Acronym: ESTC Electric Steelmaking Technology Committee

AIST Acronym: ETC Environmental Technology Committee

AIST Acronym: EUTC Energy and Utilities Technology Committee

AIST Acronym: FAT Factory Acceptance Test

AIST Acronym: GTC Galvanizing Technology Committee

AIST Acronym: HSRTC Hot Sheet Rolling Technology Committee

AIST Acronym: I&ST Iron and Steel Technology

AIST Acronym: IMTC Ironmaking Technology Committee

AIST Acronym: ISA International Steel Alliance

AIST Acronym: LHTC Lubrication and Hydraulics Technology Committee

AIST Acronym: LSRTC Ladle and Secondary Refining Technology Committee

AIST Acronym: MHTC Material Handling Technology Committee

AIST Acronym: MRPTC Metallurgy - Processing, Products and Applications Technology Committee

AIST Acronym: MRTC Maintenance and Reliability Technology Committee

AIST Acronym: MSCTC Metallurgy - Steelmaking and Casting Technology Committee

AIST Acronym: MSTS The Making, Shaping and Treating of Steel

AIST Acronym: OSTC Oxygen Steelmaking Technology Committee

AIST Acronym: PCMTC Project and Construction Management Technology Committee

AIST Acronym: PRTC Plate Rolling Technology Committee

AIST Acronym: PSTMTC Packaging, Shipping and Transportation Methods Technology Committee

AIST Acronym: PTTC Pipe and Tube Technology Technology Committee

AIST Acronym: RBRTC Rod and Bar Rolling Technology Committee

AIST Acronym: RSTC Refractory Systems Technology Committee

AIST Acronym: RTC Rolls Technology Committee

AIST Acronym: SAFTC Specialty Alloy and Foundry Technology Committee

AIST Acronym: SHTC Safety and Health Technology Committee

AIST Acronym: TETC Tinplate and Electrogalvanizing Technology Committee

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.

Alignment Key A guide in the mill base which acts as the main location reference for both driven and idle forming stands.

Aliphatic One of three types of hydrocarbons found in fuels or lubricants. Typically, aliphatics are visualized as linear molecules with no reactive chemical sites. (see Hydrocarbon)

Alkali Metal A metal in group IA of the periodic system—namely, lithium, sodium, potassium, rubidium, cesium and francium. They form strongly alkaline hydroxides, hence the name.

Alkalies Any of various bases like hydroxides of sodium, potassium and lithium which neutralize acids.

Alkaline Cleaner A material blended from alkali hydroxides and such alkaline salts as borates, carbonates, phosphates or silicates. The cleaning action may be enhanced by the addition of surface-active agents and special solvents.

Alkaline Derusting An electrical process for derusting steel, cast-iron and other ferrous alloys without using heat.

Alkaline Earth Metal A metal in group IIA of the periodic system—namely, beryllium, magnesium, calcium, strontium, barium and radium—so called because the oxides or "earths" of calcium, stronthium and barium were found by the early chemists to be alkaline in reaction.

Alkyd A type of resin made from a polyhydroxy alcohol combined chemically with the acids of various oils. They are particularly adapted for use where hardness and high gloss are required. Used largely for outside decoration.

Alligatoring 1. Pronounced wide cracking over the entire surface of a coating having the appearance of alligator hide. 2. The longitudinal splitting of flat slabs in a plane parallel to the rolled surface. Also called fish-mouthing.

Allotriomorphic Crystal A crystal whose lattice structure is normal but whose external surfaces are not bounded by regular crystal faces; rather, the external surfaces are impressed by contact with other crystals or another surface such as mold wall, or are irregularly shaped because of nonuniform growth. (see Idiomorphic Crystal)

Allotropy 1. A near synonym for polymorphism. Allotropy is generally restricted to describing polymorphic behavior in elements, terminal phases, and alloys whose behavior closely parallels that of the predominant constituent element. 2. The existence of a substance, especially an element, in two or more physical states (for example, crystals).

Allowance 1. The specified difference in limiting sizes (minimum clearance or maximum interference) between mating parts, as computed arithmetically from the specified dimensions and tolerances of each part. 2. In a foundry, the specified clearance. The difference in limiting sizes, such as minimum clearance or maximum interference between mating parts, as computed arithmetically. (see Tolerance)

Alloy A substance that has metallic properties and is comprised of two or more chemical elements, of which at least one is a metal.

Alloy Cast Iron Highly alloyed cast irons containing more than 3% alloy content. Alloy cast irons may be a type of white iron, gray iron or ductile iron.

Alloy Powder, Alloyed Powder A metal powder consisting of at least two constituents that are partially or completely alloyed with each other.

Alloy Scrap Scrap which contains one or more alloying metals, such as nickel, chromium, tungsten, molybdenum. Such scrap must be very carefully classified according to composition and kept separate from other kinds of scrap.

Alloy Steel A steel in which a deliberate addition of one or more alloying elements, e.g. Mn, Ni, Cr, Mo, etc. has been made during steelmaking to enhance the properties of the steel. The amounts of each element that must be present in steel before it is classified as an alloy steel are given in Table 1 in EN 10020:2000. At low levels of addition, the steels may be classified as low alloy. The same standard classifies steels which do not meet the minimum requirements as 'non-alloy' steels.

Alloy Surcharge The addition to the producer's selling price included in order to offset raw material cost increases caused by higher alloy prices.

Alloy Surcharge The producer's selling price plus a surcharge added to offset the increasing costs of raw materials caused by increasing alloy prices.

Alloying Element Any metallic element added during the making of steel for the purpose of increasing corrosion resistance, hardness or strength. The metals used most commonly as alloying elements in stainless steel include chromium, nickel and molybdenum.

Alloying Elements Chemical elements added for improving the properties of the finished products. Some alloying elements are nickel, chromium, manganese, molybdenum and silicon.

All-Weld-Metal Test Specimen A test specimen wherein the portion being tested is composed wholly of weld metal.

Alpha – Ferrite Body-centered cubic type of pure iron stable below 1,670°F (910°C).

Alpha Brass A solid-solution phase of one or more alloying elements in copper having the same crystal lattice as copper.

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 Martensite A form or stage of martensite of somewhat arbitrary distinction, probably representing the least developed and most distorted stage in the transformation of austenite to martensite at ordinary temperatures.

Alpha Process A shell molding and core-making method in which a thin resin-bonded shell is baked with a less expensive, highly permeable material.

Alpha-Iron The form of iron (also referred to as ferrite) which exists naturally below 910°C in which the iron atoms are arranged in a body-centered cubic (bcc) crystalline pattern, i.e., an iron atom at each corner of a cube and a single one right in the middle of the cube.

Alternate Immersion Test A corrosion test in which the specimens are intermittently exposed to a liquid medium at definite time intervals.

Alternating Blanking A method of blanking parts. This method involves having one part blanked in one direction and another part blanked in another direction utilizing the unused material from the previous part. This method is used as a cost-cutting measure.

Alternating Stress Stress produced in a material by forces acting alternating in opposite directions.

Alumel A nickel-base alloy containing about 2.5% Mn, 2% Al, and 1% Si used chiefly as a component of pyrometric thermocouples.

Alumina An oxide of aluminum.

Aluminized Sheet This is sheet steel to which a thin, hot-dip, aluminum-silicon alloy coating has been applied. It is primarily used in applications that must withstand or reflect heat and resist corrosion at temperatures that are higher than galvanized coatings can cope with. The silicon content is usually 5-11% and this promotes adherence of the coating to the substrate. Although most aluminized coatings are applied to cold rolled carbon steel, they are also used on some ferritic stainless steels in order to give car exhausts life-of-vehicle durability. Aluminized steel is very formable, and typical applications are vehicle exhaust pipes, ovens, furnaces, heat exchangers and bakeware. The coating is said to be particularly good at resisting salt spray and exhaust condensate corrosion.

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

Aluminum A silver-white soft metal, noted for its lightness, high reflectivity, high thermal conductivity, non-toxicity and corrosion resistance. It is the most abundant metallic element, comprising about 1/12th of the earth's crust. It is never found in nature as an elemental metal, but only in combination with oxygen and other elements. In ordinary commercial and industrial use, the word "aluminum" is often understood to mean aluminum alloy, rather than the pure metal.

Aluminum Killed Steel (Special Killed) Steel deoxidized with aluminum in order to reduce the oxygen content to a minimum so that no reaction occurs between carbon and oxygen during solidification.

Aluminum Oxide A chemical compound of aluminum with oxygen, which forms immediately on an unprotected surface exposed to air. Unlike iron oxide, (the rust that forms on steel) aluminum oxide does not flake off, but forms a protective layer that blocks further oxidation and so protects the integrity of the metal. It is transparent and does not alter the appearance of the aluminum surface.

Aluminum-Base, Aluminum Complex Grease A grease prepared from a lubricating oil and an aluminum soap. Such greases are made with more than one acid, often benzoic and stearic acids, and liquefy at higher temperatures than simple soaps.

Amalgam A dental alloy produced by combining mercury with alloy particles of silver, tin, copper and sometimes zinc.

Ambient Temperature The temperature of the surrounding atmosphere.

AMC Refractory Refractory composed of alumina (Al2O3), magnesia (MgO) and carbon. Used primarily in the working lining (steel contact areas) of steel ladles.

American Iron and Steel Institute (AISI) A non-profit association of North American producers, suppliers to and users of steel. It's mission is to promote steel as the material of choice and to enhance the competitiveness of its members and the North American steel industry. www.steel.org

American Standard Beam Common name for an S-shape steel beam.

Amine A specific type of organic compound containing nitrogen, used to absorb acids or as an antioxidant. Common amines include aromatic amines, MEA (monoethanol amine) and DEA (diethanol amine).

Amorphous Non-crystalline.

Amorphous Solid A rigid material whose structure lacks crystalline periodicity; that is, the pattern of its constituent atoms or molecules does not repeat periodically in three dimensions. (see Metallic Glass)

Ampacity The current carrying capacity expressed in amperes.

Anchor A ceramic or metal fitting designed to hold refractories in place.

Andalusite A mineral consisting of alumina and silica.

Anelastic Deformation Any portion of the total deformation of a body that occurs as a function of time when load is applied and which disappears completely after a period of time when the load is removed.

Anelasticity The property of solids by virtue of which strain is not a single-value function of stress in the low-stress range where no permanent set occurs.

Angle A very common structural or bar shape with two legs of equal or unequal length intersecting at 90°.

Angle Iron An iron or steel structural member that has been cast, rolled or bent (folded) so that its cross-section is I-shaped.

Angle of Bite In the rolling of metals, the location where all of the force is transmitted through the rolls; the maximum attainable angle between the roll radius at the first contact and the line of roll centers. Operating angles less than the angle of bite are termed contact angles or rolling angles.

Angle of Nip In rolling, the angle of bite. In roll, jaw or gyratory crushing, the entrance angle formed by the tangents at the two points of contact between the working surfaces and the (assumed) spherical particles to be crushed.

Angle Plate A precision holding fisture made of cast-iron, steel or granite. The two principle faces are at right angles and may be slotted for holding the work or clamping to a table.

Angles, Shapes & Section Hot rolled Structural Sections obtained by hot rolling of blooms/billets. They include angles, channels, girders, joist, I beams, H beams etc used in civil/mechanical construction.

Angtrom (Unit) A unit of linear measure equal to 10-10 m, or 0.1 nm (nanometer), sometimes used to express small distances such as interatomic distances and some wavelengths.

Angular Speed (Gears) Rotational speed at the pitch line, measured in rad/s.

Angularity The conformity to or deviation from specified angular dimensions in the cross-section of a shape.

Aniline Point For a petroleum fluid, the lowest temperature at which the product is completely miscible with an equal volume of freshly distilled aniline. It serves as a measure of the solvent or “grease-cutting” power of a hydrocarbon; generally, the lower the aniline point, the more effective the solvent.

Anion A negatively charged ion that migrates through the electrolyte toward the anode under the influence of a potential gradient. (see Cation) (see Ion)

Anisotropy Anistropy is the word used to describe the fact materials in general, and steels in particular, are characterized by mechanical properties which differ depending upon the direction in which they are assessed. Particular use is made of this in cold reduced formable steels intended for deep drawing applications; the production process route is such as to enhance this particular property, which is given a numerical value by a parameter known as the 'r' value.

Anneal A process, consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften metallic materials, such as steel. This process also simultaneously produces desired changes in microstructure, as in other properties, such as improvement of mechanical or electrical properties, increase in stability in dimensions, facilitation of cold work, etc. (see Batch Anneal) (see Continuous Anneal)

Anneal to Temper A final partial anneal that softens a cold worked non-ferrous alloy to a specified level of hardness or tensile strength.

Annealing 1. Heating and then cooling metals in a controlled atmosphere to soften them. 2. A process involving heating and cooling usually applied to induce softening. In box annealing, the material to be annealed is enclosed in a metal container with, or without packing material to minimize oxidation. The charge is usually heated slowly to a temperature just below the transformation range, but sometimes just above, or within it, and cooled slowly.

Annealing Carbon Fine, apparently amorphous carbon particles formed in white cast iron and certain steels during prolonged annealing. Also called temper carbon.

Annealing Carbon Fine, apparently amorphous carbon particles formed in white cast iron and certain steels during prolonged annealing. Also called temper carbon.

Annealing Twin A twin form in a crystal during recrystallization.

Annulus A ring-like part or, the orifice of a hollow die, through which extruded metal flows from the press.

Anode 1. The electrode of an electrolyte cell at which oxidation occurs. Electrons flow away from the anode in the external circuit. It is usually at the electrode that corrosion occurs and metal ions enter solution. 2. The positive (electron-deficient) electrode in an electrochemical circuit. Contrast with cathode.

Anode Copper Special-shaped copper slabs, resulting from the refinement of blister copper in a reverberatory furnace, used as anodes in electrolytic refinement.

Anode Effect The effect produced by polarization of the anode in electrolysis. It is characterized by a sudden increase in voltage and a corresponding decrease in amperage due to the anode becoming virtually separated from the electrolyte by a gas film.

Anode Film 1. The portion of solution in immediate contact with the anode, especially if the concentration gradient is steep. 2. The outer layer of the anode itself.

Anodic Cleaning Electrolytic cleaning in which the work is the anode. Also called reverse-current cleaning.

Anodic Protection Polarization to a more oxidizing potential to achieve a reduced corrosion rate by the promotion of passivity.

Anodic Reaction Electrode reaction equivalent to a transfer of positive charge from the electronic to the ionic conductor. An anodic reaction is an oxidation process. An example common in corrosion is M(s) – M(aq)2+ + 2e-.

Anodizing Forming a conversion coating on a metal surface by anodic oxidation; most frequently applied to aluminum.

Anolyte The electrolyte adjacent to the anode in an electrolytic cell.

ANSI American National Standards Institute

ANSI American National Standards Institute (a member of the ISO). Among other things, ANSI standards are used to evaluate load ratings for ball and roller bearings. www.ansi.org

Antifriction Material A material that exhibits low-friction or self-lubricating properties.

Antimony Chemical symbol Sb. Silvery white and lusteous, it exhibits poor heat and electrical conductivity. It is used primarily in compounds such as antimony trioxide for flame-retardants. Other applications include storage battery components.

Antioxidant An additive to retard oxygen-related deterioration, especially oxidation of lubricants.. (see Inhibitor)

Antipitting Agent An addition agent for electroplating solutions to prevent the formation of pits or large pores in the electrodeposit.

Anti-Seize Compounds (Pipe Dope) Grease-like substances with graphite, molybdenum disulfide and metallic particles dispersed throughout, primarily to prevent seizure on threaded joints.

Anti-two-block device (A-2-B) A device that when activated, disengages all crane functions which can cause two-blocking.

Anvil A heavy iron or steel block upon which metal is forged or hammered. Also the fixed jaw on a micrometer against which parts are measured.

AOD Process AOD stands for argon Argon Oxygen Decarburization, a refining process associated with the production of stainless steel. Most stainless steel is initially produced in an electric arc furnace before being transferred to a separate ladle furnace for refining to achieve the precise metallurgical content required – a process known as secondary metallurgy or secondary refining. In the AOD process, a mixture of argon and oxygen is blown through the molten steel in the ladle furnace, and the oxygen achieves the main objective of oxidizing unwanted carbon in the steel melt. But because the vital and expensive chromium contained in all stainless steels is also prone to oxidation and subsequent loss with the process slag, the argon is introduced to inhibit this reaction.

APB AIST Process Benchmarker. The AIST Process Benchmarker (APB) is an online analytical tool for tracking performance metrics between iron, steel and coke-producing companies. This service allows producer members to compare specific operating parameters in a multitude of ways. The user-friendly, subscriber-only database system gives producers the ability to generate many different reports, charts, tables and even raw data, all of which can be exported to a variety of standard formats for use in presentations, status reports and technical papers.

Aperature In an extrusion die, the shaped opening through which the heat-softened metal is forced and which gives the extruded product its cross-sectional shape. Also called the “orifice”.

API American Petroleum Institute, the trade association of the oil industry. www.api.org

API Gravity A gravity scale established by the API, in general use in the petroleum industry. This unit is defined in terms of specific gravity at 60°F (SPG 60°F) as follows: Degrees API = 141.5/SPG 60°F - 131.5.

API Separator (Lube Systems) A tank with baffles, used to separate oil from water: the water is removed by the underflow and the oil by the baffle overflow.

Apparent Consumption This is a stastically-derived figure for national or regional steel consumption during a given period. It is based on the sum of reported mill shipments of finished steel plus steel imports into the country/region, minus steel exports. While a useful indicator, it does not necessarily accurately reflect real steel demand. This is because stock building or stock depletion in the supply chain (by distributors and/or steel users) can result in apparent consumption either exaggerating or under estimating true steel demand.

Apparent Density 1. The weight per unit volume of a powder, in contrast to the weight per unit volume of the individual particles. 2. The weight per unit volume of a porous solid, where the unit volume is determined from external dimensions of the mass. Apparent density is always less than the true density of the material itself.

Apparent Viscosity A term characterizing the resistance to flow of liquids whose viscosities vary with the rate of shear. It can be evaluated in a capillary-type instrument where it is defined as the shear stress at the capillary wall divided by the mean rate of shear as computed from the Poiseuille equation; it is expressed in fundamental viscosity units at a given rate of shear.

Apron Device that the molten slag flows across on its way from the spout to the doughnut. It is cooled by water spray.

Aqueous Cleaning A common method of removing lubricants which consists of three stages: washing, rinsing, and drying.

Arbor A shaft or spindle for holding cutting tools; most usually on a milling machine.

Arbor Press A machine used for forcing arbors or mandrels into drilled or bored parts preparatory to turning or grinding. Also used for forcing bushings, shafts or pins into or out of holes.

Arbor-Type Cutter A cutter having a hole for mounting on an arbor and usually having a keyway for a driving key.

Arc A luminous discharge of electrical current crossing the gap between two electrodes.

Arc Blow The deflection of an electric arc from its normal path because of magnetic forces.

Arc Brazing A brazing process in which the heat required is obtained from an electric arc. (see Carbon Arc Brazing)

Arc Cutting A group of cutting processes that melt the metals to be cut with the heat of an arc between an electrode and the base metal. See Carbon Arc Cutting, Metal Arc Cutting, Gas Metal Arc Cutting, Gas Tungsten Arc Cutting, Plasma Arc Cutting and Air Carbon Arc Cutting. Compare with Oxygen Arc Cutting.

Arc Furnace A melting unit in which the heat is generated by striking an arc between graphite electrodes and the metal charge, which is usually in the form of solid scrap.

Arc Gouging An arc cutting process variation used to form a bevel or groove.

Arc of Approach (Gears) Short distance of sliding contact between the dedendum of the driving tooth and the addendum of the driven tooth.

Arc Seam Weld A seam weld made by an arc welding process.

Arc Spot Weld A spot weld made by an arc welding process.

Arc Spraying (ASP) A thermal spraying process using an arc between two consumable electrodes of surfacing materials as a heat source and a compressed gas to atomize and propel the surfacing material to the substrate.

Arc Strike A discontinuity consisting of any localized remelted metal, heat-affected metal, or change in the surface profile of any part of a weld or base metal resulting from an arc.

Arc Welding A group of welding processes that produce coalescence of metals by heating them with an arc, with or without the application of pressure, and with or without the use of filler metal.

Arcair Torch An electric arc torch with air ducts running parallel to the electrode, used to remove metal and surface defects from ferrous castings.

Architectural Finish An architectural finish is a standard finish characterized by a uniformly good appearance. This finish is most often specified for "exposed" surfaces.

Argon Oxygen Decarburization (AOD) A secondary refining process for the controlled oxidation of carbon in a steel melt. In the AOD process, oxygen, argon and nitrogen are injected into a molten metal bath through submerged, side-mounted tuyeres.

Argon Shroud A procedure using argon gas to shield molten steel from oxygen as it is teemed from the ladle.

Argon Stirring An inert gas introduced through a nozzle to stir molten steel to promote chemical and temperature homogenization and float out inclusions.

Armor Plate A protective plate used on battleships, tanks, airplanes, etc. These plates must be very hard, very tough, and thick enough for the protection required. Armor plate varies from 1/4 to 18 in. in thickness.

Aromatics Ring-structured hydrocarbons found in petroleum that contain unsaturated double bonds. Benzene is the simplest aromatic. (see Benzene) (see Hydrocarbon)

Artifact A feature of artificial character, such as a scratch or a piece of dust on a metallographic specimen, that can be erroneously interpreted as a real feature.

Artificial Aging Aging above room temperature. Compare with Natural Aging. (see Aging (Heat Treatment))

Artificial Aging Aging above room temperature. Compare with Natural Aging. (see Aging)

As Rolled The condition the material is in when it comes off the sizing rollers, cooling as it’s being processed. As rolled tends to result in hard spots and higher as-shipped hardness.

As-Cast Condition Castings as removed from the mold without subsequent heat treatment.

ASD Aluminum Standards and Data, published by the Aluminum Association.

Ash Box Brick-lined collection point for slag and ash.

Ash Content Percentage of non-combustible residue of a lubricating oil or fuel, as determined by ASTM D 482 or D 874. Ash reveals the presence of metals, including the calcium, magnesium and zinc introduced by additives. The heavy metals formerly used also appeared in the ash.

Ash Tank Holding tank for ashes. The tank is located outside the boiler house. The ashes are dumped once or twice a week, depending on the ash accumulation.

Askania 1. A strip-centering device consisting of two electric eyes to ensure that the strip will stay centered during recoiling. 2. Device with an electronic eye which is associated with tracking of strip going through the side trimmers.

ASLE American Society of Lubrication Engineers

ASME American Society of Mechanical Engineers. www.asme.org

Asperities Microscopic projections on metal surfaces, invisible to the naked eye, that create peaks and valleys, even after grinding or machining. When two surfaces are in sliding contact, these imperfections cause interference that results in friction; without proper lubrication, wear, scoring or welding will follow.

Asphalt/Bitumen A soft black or dark brown tacky residual material containing asphaltenes, compound of sulfur, nitrogen and tar. Asphalt, derived from petroleum, is solid at normal temperatures; as an adjective, “asphalt” is often used to describe viscous open gear compounds or black, tacky greases.

Asphaltenes Asphaltic materials soluble in aromatic solvents but insoluble in naphtha.

Asphaltic Similar in color and tackiness to asphalt.

Assay A chemical test performed on a mineral sample to determine the concentration of valuable metal contained.

Assembly Fit Refers to two parts designed for mating assembly and requiring exact dimensions and contours to assure a proper fit.

Association for Iron & Steel Technology (AIST) An international non-profit association of producers, suppliers and users of steel and iron. The organization’s goal is the advancement of technical development, production, processing and applications of iron and steel.

ASTM American Standard of Testing and Materials. A non-profit organization that provides a forum for producers, users, ultimate consumers, and those having a general interest (representatives of government and academia) to meet on common ground and write standards for materials, products, systems, and services. Www.astm.org

ASTM American Standard of Testing and Materials

ASTM Standards A series of documents, approved and published by ASTM, that include specifications or requirements, practices, guides, test methods, etc., covering various materials, products, systems or services. In the steel industry, the steel related ASTM standards are used by both the producers and users to ensure that a steel product or service meets all intended requirements. (see American Society for Testing and Materials)

As-Welded The condition of weld metal, welded joints and weldments after welding, but prior to any subsequent thermal, mechanical or chemical treatments.

Athermal Transformation A reaction that proceeds without benefit of thermal fluctuations; that is, thermal activation is not required. Such reactions are diffusionless and can take place with great speed when the driving force is sufficiently high. For example, many martensitic transformations occur athermally on cooling, even at relatively low temperatures, because of the progressively increasing driving force. In contrast, a reaction that occurs at constant temperature is an isothermal transformation; thermal activation is necessary in this case and the reaction proceeds as a function of time.

Atmosphere Valve A valve that is located in the exhaust line of a turbine and is designed to open up and get a positive pressure in the exhaust line.

Atmosphere, Furnace Gases with which metal is in contact during melting or heat treating.

Atmosphere, Neutral Furnace atmosphere which is neither oxidizing nor reducing can be made up of an inert gas, e.g., argon, or the products of combustion.

Atmosphere, Oxidizing Furnace atmosphere which gives off oxygen under certain conditions or where there is an excess of oxygen in the product of combustion, or the products of combustion are oxidizing to the metal being heated.

Atmosphere, Reducing Furnace atmosphere which absorbs oxygen under suitable conditions or in which there is insufficient air to completely burn the fuel, or the product of combustion is reducing to the metal being heated.

Atmospheric Corrosion The gradual degradation or alteration of a material by contact with substances present in the atmosphere, such as oxygen, carbon dioxide, water vapor, and sulfur and chlorine compounds.

Atmospheric Riser

Atmospheric Riser A riser that uses atmospheric pressure to aid feeding. Essentially, a blind riser into which a small core or rod protrudes; the function of the core or rod is to provide an open passage so that the molten interior of the riser will not be under a partial vacuum when metal is withdrawn to feed the casting, but will always be under atmospheric pressure.

Atomic Number (Z) The number of protons in an atomic nucleus, which determines the individuality of the atom as a chemical element.

Atomic Percent The number of atoms of an element in a total of 100 representative atoms of a substance.

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 material is optional.

Atomization The disintegration of a molten metal into particles by a rapidly moving gas or liquid stream or by other means.

Atomizing Steam Low pressure steam which is introduced to the oil gun to help atomize the oil, to assist the burning process, and to keep the oil gun from plugging.

Attemperator Header connecting the primary and finishing superheaters into which feedwater is sprayed to control the final temperature of the steam leaving the boiler.

Attenuation A reduction in intensity, usually of a waveform, measured in decibels or as a percentage of fraction of loss.

Attritious Wear Wear of abrasive grains in grinding such that the sharp edges gradually become rounded. A grinding wheel that has undergone such wear usually has a glazed appearance.

Attritor A high-intensity ball mill whose drum is stationary and whose balls are agitated by rotating baffles, paddles or rods at right angle to the drum axis.

Attritor Grinding The intensive grinding or alloying in an attritor. Examples: milling of carbides and binder metal powders and mechanical alloying of hard dispersoid particles with softer metal or alloy powders. (see Mechanical Alloying)

Auger Electron An electron emitted from an atom with a vacancy in an inner shell. Auger electrons have a characteristic energy detected as peaks in the energy spectra of the secondary electrons generated.

Auger Electron Spectroscopy (AES) A technique for chemical analysis of surface layers that identifies the atoms present in a layer by measuring the characteristic energies of their Auger electrons.

Ausforming Hot deformation of metastable austenite within controlled ranges of temperature and time that avoids formation of non-martensitic transformation products.

Austempered Ductile Iron A moderately alloyed ductile iron that is austempered for high-strength with appreciable ductility. (see Austempering)

Austempering Heat treatment involving quenching a steel object from a temperature above the transformation range in a medium maintained at a temperature above the Martensitic range sufficiently fast to avoid the formation of high temperature transformation products, and then holding it at that temperature until transformation is complete.

Austenite High-temperature solid form of steel with face-centered cubic crystal structure.

Austenitic Grain Size Size attained by the grains in steel when heated to the austenitic region.

Austenitic Manganese Steel A wear-resistant material containing about 1.2% C and 12% Mn. Used primarily in the fields of earthmoving, mining, quarrying, railroading, ore processing, lumbering, and in the manufacture of cement and clay products. (see Hadfield Manganese Steel)

Austenitic Steels These are steels which contain sufficient austenite stabilizing elements, such as Mn, Ni and N, so that the microstructure of the steel is austenitic at room temperature. Such steels cannot be quench or air hardened, but will work harden rapidly; they are non-magnetic. Important examples of austenitic steels are 18/8 (18% Cr, 8% Ni) stainless steel and Hadfield's Manganese (14% Mn) steel.

Austenizing Forming austenite by heating a steel object above the transformation range.

Autogenous Weld A fusion weld made without the addition of filler metal.

Autoignition Temperature The minimum combustion temperature for a vapor-air mixture without an open flame. It permits evaluation of the fire hazards of vapors.

Automatic Crane A crane which when activated operates through a preset cycle or cycles.

Automatic Gauge Control Using hydraulic roll force systems, steelmakers have the ability to control precisely their steel sheet’s gauge (thickness) while it is traveling at more than 50 miles per hour through the cold mill. Using feedback or feed-forward systems, a computer's gap sensor adjusts the distance between the reduction rolls of the mill 50-60 times per second. These adjustments prevent the processing of any off-gauge steel sheet.

Automatic Particle Counters Electronic devices that measure the contamination level of fluid by the counting of the particles in the fluid, more commonly by light blockage or light scattering. Typically, the particles are measured in several size ranges and the near instantaneous results are provided in the number of particles per unit volume of the fluid.

Automatic Press A press in which the work is fed mechanically through the press in synchronism with the press action. An automation press is an automatic press that, in addition, is provided with built-in electrical and pneumatic control equipment.

Automatic Stop A device which may be attached to any of several parts of a machine tool to stop the operation of the machine at any predetermined point.

Automatic Welding Welding with equipment that performs the welding operation without adjustment of the controls by a welding operator. The equipment may or may not load and unload the workpieces. Contrast with Machine Welding.

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

Auxiliary Anode In electroplating, a supplementary anode positioned so as to raise the current density on a certain area of the cathode and thus obtain better distribution of plating.

Auxiliary Electrode An electrode commonly used in polarization studies to pass current to or from a test electrode. It is usually made from a noncorroding material.

Auxiliary Hoist A supplemental hoisting unit, usually designed to handle lighter loads at a higher speed than the main host.

Auxiliary hoist line (whipline) A secondary rope system usually of lighter load capacity than that provided by the main rope system.

Auxiliary Hydraulic system Hydraulic system that supplies the force to run the various hydraulic cylinders associated with the finishing mill which are not taken care of by the AGC or CVC hydraulic systems.

Auxiliary Oil Pump A steam or electric pump that maintains oil pressure on the controls and the bearings of a turbo blower when it is not up to maximum speed.

Auxiliary Operations Additional processing steps performed on forgings to obtain properties, such as surface conditions or shapes, not obtained in the regular processing operation.

Auxiliary Pump Pump on the auxiliary system which supplies the pressure for the system.

Auxilliary Air A controller for auxiliary air dampers on boilers. For proper combustion on oil fire.

AWG (American Wire Gauge) A system of conventional designations of standard wire diameters. For example, “10-gauge” denotes wire of 0.135-inch diameter. In the AWG system, higher numbers designate smaller diameters and lower numbers designate larger diameters.

Axial Load Bearing A bearing that supports an axial thrust (a load exerted in line with the length or the axis of a shaft).

Axial Rolls In ring rolling, vertically displaceable frame opposite from but on the same centerline as the main roll and rolling mandrel. The axial rolls control the ring height during the rolling process.

Axis The line, real or imaginary, passing through the center of an object about which it could rotate; a point of reference.

Axis of Rotation (center of rotation) The vertical axis around which the cranes upperworks (superstructure) rotates.

Axle, Fixed A shaft which is fixed in the end truck and about which the wheel revolves.

Axle, Rotating A shaft which is fixed in the wheel and which rotates on bearings fixed in the end truck.



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