STEEL TERMS GLOSSARY: A - B
AGE HARDENING (AGING) - Spontaneous, gradual change in mechanical properties causing increased hardness, yield strength and tensile strength accompanied by a loss of ductility. Nonkilled cold rolled steels are especially prone to this condition.
AISI STEELS - Steels specified by the AMERICAN IRON AND STEEL INSTITUTE.
ALLOY STEEL - Steel containing substantial amounts 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.
ALUMINUM - (Chemical Symbol AI) - Silvery white metal used in steelmaking as a 1.) deoxidizer; 2.) grain refiner; 3.) alloying agent in nitriding steels; and 4.) a coating for aluminized steels.
ALUMINIZED STEEL - Steel coated with aluminum by a hot dip process to impart corrosion resistance.
ANNEALING - A generic term denoting a treatment, consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. The purpose of such changes may be, but is not confined to, one or more of: improvement of machinability; facilitation of coldwork; improvement of mechanical or electrical properties or increase in stability of dimensions.
ASTM - Abbreviation for AMERICAN SOCIETY FOR TESTING MATERIAL. An organization for issuing standard specifications on materials.
AUSTEMPERING - A heat treating process that consists of quenching steel from a temperature above the transformation range into a medium (usually molten salt) having a rate of heat extraction sufficiently high to prevent the formation of pearlite by maintaining the temperature between the pearlite temperature range and the martensite start temperature until transformation is complete.
AUSTENITE - A phase in plain carbon and low alloy steels that is stable only above approximately 1330°F. Certain high alloy and stainless steels contain sufficient amounts of austenite stabilizer (nickel, manganese) to be austenitic at room temperature.
AUSTENITIZING - Forming austenite by heating a ferrous alloy into the transformation range (partial austenitizing) or above the transformtion range (complete austenitizing). When used without qualification, the term implies complete austenitizing.
BAINITE - A needle-like, acicular microstructure appearing in spring steel strip characterized by high hardness with ductility and toughness greater than tempered martensite. Bainite is produced by cooling austenite at a rate sufficiently fast to avoid formation of pearlite and holding at a temperature below that at which pearlite forms but above the martensite start temperature.
BANDED STRUCTURE - A microstructure consisting of parallel bands of iron carbide and ferrite.
BASE BOX - An arcane method of designating thickness that is peculiar to tin mill products (see TIN PLATE BASE BOX).
BASIC OXYGEN PROCESS - A pneumatic steelmaking process wherein high purity oxygen is blown onto the surface of a bath of molten iron oxidizing impurities and promoting slag-metal refining reactions.
BATCH ANNEAL - Any process involving annealing of steel in coils. Because of the large masses of steel involved, heat up and cool down rates are relatively low.
BEND TEST - A test used to index the ductility or formability of flat rolled steel which consists of bending the material around a specified radius that is frequently expressed in multiples of the material thickness (1 x T = a radius that is one times the thickness of the material). The direction of the bend axis is normally specified also: along the rolling direction (unfavorable) or transverse to the rolling direction favorable).
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) From 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 551bs. to 2751bs. base box weight. It is used either as is for stampings, or may be enameled or painted or tin or terne coated.
BLANK - A flat piece of steel produced in blanking dies or by shearing for an identified part. Blanks are usually formed further in subsequent press operations.
BLAST FURNACE - A vertical shaft type smelting furnace in which an air blast is used, usually hot, for producing pig iron. The furnace is continuous in operation using iron ore, coke and limestone as raw materials which are charged at the top while the molten iron and slag are collected at the bottom and are tapped out at intervals.
BLISTER - A small raised area on the surface resulting from the expansion of gas concentrated at a subsurface inclusion or porosity. May occur as isolated spots, but often found in longitudinal streaks.
BLUING - (1) Sheets - A method of coating sheets with a thin, even film of bluish-black oxide, obtained by exposure to an atmosphere of dry steam or air; generally this is done during box annealing. (2) Tempered spring steel strip - an oxide film blue in color produced by low temperature heating.
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) - an alloy addition that is used to improve hardenability or reduce hardness. In medium and high carbon steels up to approximately .50 carbon, boron, added with small amounts of titanium for protection from nitrogen, enhances heat treat response. In low carbon, aluminum killed steels, unprotected boron additions combine with the nitrogen present which reduces the material's as-hot rolled hardness.
BOX ANNEALING - A process of heating coils of steel in a closed container filled with a non-oxidizing atmosphere. The charge is usually heated slowly to a temperature below the transformation range, held for sufficient time to equalize temperature throughout the coil, and then slow cooled. When used commercially, a BOX ANNEAL implies a shorter, less costly anneal than a SPHEROIDIZED ANNEAL.
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. Uses include Rockwell A and C scales.
BRAZING - Joining metals by fusion of nonferrous alloys that have melting points above 800°F. but lower than those of the metals being joined. This may be accomplished by means of a torch (torch brazing), in a furnace (furnace brazing) or by dipping in a molten flux bath (dip or flux brazing). The 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 integrally bonded, as in brazing sheet.
BREAKS - Creases or ridges usually in 'untempered' or in aged material where the yield point has been exceeded. Depending on the origin of the break, it might be termed a crossbreak, a coil break, an edge break, a sticker break, etc.
BRIGHT ANNEALING - A process of annealing usually carried out in a controlled furnace atmosphere so that surface oxidation is reduced to a minimum and the surface remains relatively oxide free.
BRIGHT COMMERCIAL FINISH - Refer to FINISHES.
BRINELL HARDNESS (TEST) - A common standard method of measuring the hardness of relatively thick metals. The smooth surface of the metal is subjected to indentation by a hardened steel ball under pressure or load. The diameter of resultant indentation in the metal surface is measured by a special microscope and the Brinell hardness value read from a chart or calculated by formula.
BRITTLENESS - A tendency to fracture without appreciable deformation.
BROACHING - Multiple shaving, accomplished by pushing a tool with stepped cutting edges along the work, particularly through holes.
BUCKLE - Alternate bulges or hollows recurring along the length of the product with the edges remaining relatively flat.
BURR - A thin ridge or roughness left by a cutting operation such as in metal slitting, shearing, blanking or sawing. This is common to a
BUTT WELDING - Joining two edges or ends by placing one against the other and welding them.