A.S.T.M. - American Society for Testing Material, an organization for issuing standard specifications on material, including metals and alloys.
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.
Age Hardening - The term as applied to soft or low carbon steels, relates to 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 - Spontaneous changes in the physical properties (for example, increase in tensile strength and hardness) of some metals, which occur on standing at atmospheric temperatures after final cold working or after a final heat treatment. Frequently synonymous with the term “Age-Hardening.”
Air Cooling - Cooling of the heated metal, intermediate in rapidity between slow furnace cooling and quenching, in which the metal is permitted to stand in the open air.
Air Hardening Steel - A steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. 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.
AISI (American Iron and Steel Institute) - Steels of the American Iron and Steel Institute. AISI is a North American trade association with 50 member companies and more than 100 associate members. These companies represent the United States, Canada, and Mexico in all aspects of the steel industry. Common and alloy steels are numbered in a system essentially the same as the SAE. The AISI system is more elaborate than the SAE in that all numbers are proceeded by letters: “A” represents basic open-hearth alloy steel, “B” acid Bessemer carbon steel, “C” basic open hearth carbon steels, “CB” either acid Bessemer or basic open-hearth carbon steel, “E” electric furnace alloy steel.
Alloy - A substance that has metallic properties and is composed of two or more chemical elements, of which at least one is metal.
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 - The adding of any metallic element in stainless steel production in order to increase hardness, strength, or corrosion resistance. Molybdenum, nickel, and chromium are common alloying elements in stainless steel.
Alpha - In titanium, it is the hexagonally closed packed crystal structure that exists at lower temperatures.
Alpha Case - The alpha-stabilized surface (oxygen-, nitrogen-, or carbon-enriched) on titanium that results from elevated temperature exposure in an air furnace.
Angularity - The conformity to or deviation from specified angular dimensions in the cross section of a shape.
Annealing - A generic term denoting a heat treatment consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften but also to simultaneously produce desired changes in other properties or microstructure.
Anodic Protection - Polarization to a more oxidizing potential to achieve a reduced corrosion rate by the promotion of passivity.
AOD - See Argon-Oxygen-Decarburization
Argon-Oxygen-Decarburization (AOD) - A steel refinement process by whereby carbon is removed from molten steel through oxidation when a mixture of argon and oxygen is blown through the heat.
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.
Austenite - Phase in certain steels, characterized as a solid solution, usually off carbon or iron carbide, in the gamma form of iron. Such steels are known as “austenitic.” Austenite is stable only above 1333°F (720°C) in a plain carbon steel, but the presence of certain alloying elements, such as nickel and manganese, stabilizes the austenitic form, even at normal temperatures.
Austenitic Steel - Steel which, because of the presence of alloying elements such as manganese, nickel and chromium, shows stability of austenite at normal temperatures.
Bar - Semi-finished or finished piece of metal in a straight length.
Bath Annealing - Immersion in 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.
Beam - Long pieces of squared-off metal, normally stainless steel, which are used in building construction.
Bend Test - Various tests used to determine the toughness and ductility of flat rolled metal sheet, strip or plate, in which the material is bent around its axis 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 used then line the jaws with some soft metal or brass, so as to permit a free flow of the metal in the sample being tested.
Bessemer Process - A steelmaking process in which air is blown through the molten iron so that the impurities are thus removed by oxidation. Sir Henry Bessemer (1813-1898) was an English inventor who patented the first inexpensive industrial process for the mass-production of steel from molten pig iron.
Beta - In titanium, this body-centered cubic crystal structure exists at higher temperatures.
Billet - An ingot or bloom that has been reduced through rolling or hammering to an approximate size of 2 to 7 inches square, or to an approximate rectangular cross section of an equivalent area. Billets are classified as a semi-finished form of stainless steel that is used for long products such as bars and forgings.
Blank - A section of sheet stainless steel that has the outer dimensions of a specific part but has not yet been stamped by the end user. This lowers stainless steel processor's labor and transportation costs.
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 that are charged at the top while the molten iron and slag are collected at the bottom and are tapped out at intervals.
Blister - A raised spot on the surface of the metal caused by expansion of gas in a subsurface zone during thermal treatment.
Bloom - A semi-finished form of stainless steel that will be further processed into mill products. A bloom generally has a cross section greater than 36 square inches.
Blooming Mill - A hot rolling mill that takes continuously cast slabs or ingots and processes them into blooms.
Blowhole - A cavity produced during solidification of metal by evolved gas, which, in failing to escape, is held in pockets.
Brazing - Brazing and soldering are techniques for joining metals in the solid state by means of a fusible filler metal with a melting point well below that of the base metal.
Bright Annealed Wire - Steel wire bright drawn and annealed in controlled, non-oxidizing atmosphere furnace.
Bright Annealing - A process of annealing usually carried out in a controlled atmosphere so that the surface oxidation is reduced to a minimum and the surface remains relatively bright.
Brinell Hardness Test - A common standard method of measuring the hardness of certain metals. The smooth surface of the metal is subjected to indentation by a hardened steel ball under pressure or load. The diameter of the resultant indentation in the metal surface is measured by a special microscope and the Brinell hardness value read from a chart or calculated formula.
Brittle Fracture - A fracture that has little or no plastic deformation.
Broken Surface - Surface fracturing, generally most pronounced at sharp corners, and minute cracks on the surface of a drawn product to the direction of drawing.
Burr - A subtle ridge on the edge of strip stainless steel resulting from cutting operations such as slitting, trimming, shearing, or blanking. For example, as a stainless steel processor trims the sides of the sheet stainless steel parallel or cuts a sheet of stainless steel into strips, its edges bend with the direction of the cut. Further processing removes the burr.
Camber - Curvature of a straight plane. Not to be confused with a bow. Standard steel industry tolerance for camber is 1/8 inch in 5 feet.
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.
Carburizing - The oldest method of case hardening in which carbon is added 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.
Case Hardening - Hardening a ferrous alloy to make the outside (case) much harder than the inside (core). This can be done by carburizing, cyaniding, nitriding, carbon nitriding, induction hardening or flame hardening. Their application to stainless steel is limited wherever they decrease corrosion resistance.
Cast Steel - Any object made by pouring molten steel into molds.
Casting - To shape molten metal by pouring into a mold to produce an ingot or a continuously cast slab.
Cathodic Corrosion - Corrosion caused by a reaction of an amphoteric metal with the alkaline products of electrolysis.
Cathodic Inhibitor - A chemical substance that prevents or slows a cathodic or reduction reaction.
Cathodic Protection - Reducing the corrosion of a metal by making the particular surface a cathode of an electrochemical cell.
Cavitation - The rapid formation and depletion of air bubbles that can damage the material at the solid/liquid interface under conditions of severe turbulent flow.
CD Source - Closed Drift ion source. "Closed-Drift" refers to the physics of the ion source operation. The electrons that maintain the plasma are confined by electric and magnetic fields that interact and capture the electrons in the front of the source. The electrons effectively are forced to "drift" around a circular path.
Cellular Manufacturing - A manufacturing philosophy that puts related processes together to make a finished component in a continuous flow, as opposed to a series of batch operations.
Centerless Grinding - An operation whereby the surface of a bar is ground without using a lathe.
Charge - The material that is loaded into an electric furnace that will melt into a composition that will produce a stainless molten product. Normally recycled are scrap, iron and alloying elements.
Charpy Test - A notched-bar or impact test in which a notched specimen, fixed at both ends, is struck behind the notch by a striker carried on a pendulum. This test is used to determine the pounds of pressure required to break the sample.
Chatter - An uneven surface on drawn products usually formed by vibration of the metal during drawing.
Chemical Analysis - A report of the chemical composition of the elements and their percentage that form a metal alloy.
Chloride Stress Corrosion Cracking - Cracking due to the combination of tensile stress and corrosion in the presence of water and chlorides.
Chromium (Cr) - An alloying element that is used in stainless steel to deter corrosion. It is of bright silvery color and is relatively hard. It is strongly resistant to atmospheric and other oxidation. Its principal functions as an alloy in steel making include: (1) increased resistance to corrosion and oxidation; (2) increased hardenability; (3) additional strength at high temperatures; (4) resistance to abrasion and wear (with high carbon).
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.
CIM - Ceramic Injection Moulding, a production technique where ceramic powders are mixed with a plastic into a pliable paste and forced into a mould.
Cladding - Application of a stainless steel coating to a lower-alloy steel by means of pouring, welding, or coating to increase corrosion resistance at a lower cost than using steel exclusively.
CNC Machining - Computer Numerically Controlled Machining
Coefficient of thermal expansion - Either volumetric or linear this describes the expansion that occurs with a change in temperature. Volumetric describes the volume change whereas linear describes the change in dimensions.
Coil Products - Products that are wound into a spiral of concentric rings.
Cold Drawing - The process of passing unheated steel through dies for the purpose of reducing its cross-sectional area, imparting to it a particular shape.
Cold Finished Bars - Hot rolled stainless steel bars that are annealed and cold worked to produce a higher surface quality and higher strength. The term “cold finished” is an umbrella definition for any material that has had some sort of surface treatment. For example, cold drawn, centerless ground, and smooth turned bar are cold finished.
Cold Forming (Cold Working) - Any mechanical operation that creates permanent deformation, such as bending, rolling, drawing, etc., performed at room temperature that increases the hardness and strength of the stainless steel.
Cold Heading - Process of forcing metal to flow cold into dies to form thicker sections and more intricate shapes.
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.
Cold Rolling - The process of passing unheated steel through pairs of driven rolls for the purpose of reducing its thickness.
Cold Working - Any permanent deformation of unheated steel accomplished by the application of mechanical forces to the metal surface.
Cold-Rolled Strip (Sheet) - Stainless steel that has been run through a cold reduction mill. Sheet is under 3/16th of an inch and 24 inches wide and over. Strip is under 3/16 of an inch and under 24" wide.
Concentricity - Center to end of the circle. All round bars have three tolerances to consider: size, straightness, and out of round. The “out of round” tolerance could affect the concentricity of a bar.
Constituent - A necessary part or element; component.
Consumet - Carpenter’s trade name for “consumable electrode vacuum melt.”
Continuous Casting (strand casting) - A steel-forming process whereby molten metal is solidified into a semi-finished(hyphenate) billet, bloom, or slab for subsequent rolling in the finishing mills.
Continuous Furnace - Furnace, in which the material being heated moves steadily through the furnace.
Converter/Processor - Stainless steel customers demanding stainless steel in a more finished state such as tubing, pipe, and cold-rolled strip from re-rollers and tube makers.
Corrosion - Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents.
Corrosion Fatigue - Cracking due to repeating and fluctuating stresses in a corrosive environment.
Corrosion Potential - The potential of a corroding surface in an electrolyte relative to a reference electrode under open-circuit conditions.
Corrosion Resistance - A metal's ability to resist corrosion in a particular environment.
Creep - Strain caused by the stress that occurs over time. Slow, permanent deformation in a metallic specimen produced by a relatively small steady force below the elastic limit, acting for a long period of time.
Crevice Corrosion - Corrosion of stainless steel on the surface that is fully shielded from air, preventing the formation of a passive film.
Critical Pitting Potential - The lowest value of oxidizing potential at which pits can form and grow. The value depends on the test method used.
Critical Range - A temperature range in which an internal change takes place within a metal. Also referred to as transformation range.
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.
Cut-to-Length - Cutting flat-rolled stainless steel into desired length and then normally shipped flat-stacked.
CVD - Chemical Vapour Deposition, a production technique involving the reaction of gaseous chemicals, the product of which will deposit onto a prepared substrate.
Deburring - Removing the subtle ridge from the edge of strip metal that results from cutting operation such as slitting, trimming, shearing, or blanking.
Decarburization - Removal of carbon from the outer surface of iron or steel, usually by heating in an oxidizing or reducing atmosphere. Water vapor, oxygen and carbon dioxide are strong decarburizers. Reheating with adhering scale is also strongly decarburizing in action.
Degassing Process - In steel making, removing gases from the molten metal by means of a vacuum process in combination with mechanical action.
Descaling - A process that removes the oxide scale from the surface of the stainless steel, which develops from hot operations such as forging.
Dielectric Constant - The relative permittivity of a material. Indicates the ability of a material to store electrical energy when a voltage is applied to it.
Dielectric Loss - This is the proportion of energy that is dissipated within a dielectric material and lost as heat in an electrostatic field.
Dielectric Strength - The minimum electric field that produces breakdown of the insulating properties of the dielectric.
Dissipation Factor - The dissipation factor is a measure of the loss of power that takes place in virtually all dielectric materials, usually in the form of heat. It is expressed as the ratio of the resistive (loss) component of the current to the capacitive component of current, and is equal to the tangent of the loss angle.
DLC - Diamond-Like Carbon
Drawing (Drawn) - The process of pulling material through a die to reduce the size, change the cross sectional shape, or harden the material. A forming process that presses metal into or through a die (as in cold drawn wire).
Drawing Back - Reheating after hardening to a temperature below critical for the purpose of changing the hardness of the steel (see tempering).
Drawn-Over-Mandrel - To produce specialty tubing, this procedure uses a draw bench to pull tubing through a die and over a mandrel, allowing excellent control of the inside diameter and wall thickness.
Drill Rod - A term given to an annealed and polished high-carbon tool steel rod, usually round and centerless ground. Drill rods are used principally by machinists and tool and die makers for punches, drills, taps, dowel pins, screw machine parts, small tools, etc.
Ductility - The property that enables metals to be mechanically deformed when cold without fracturing. In steel, ductility is usually measured by elongation, and reduction of area is determined in a tensile test. A measurement of the malleability of stainless steel in terms of the amount of deformation it will withstand before failure.
Duplex - Stainless steel comprised of austenitic and ferritic stainless steels that contain high amounts of chromium and nickel. This combination is stronger than both of the individual stainless steels. Duplex stainless steels are highly resistant to corrosion and cracking.
Edge Rolling (Edge Conditioning) - To facilitate customer manipulation, strips of stainless steel are rolled to smooth the edges and remove any burrs.
Elastic Springback - When stainless steel is bent, the metal towards the outside of the bend is in tension and the metal towards the inside is in compression. If the applied bending force is not sufficient to cause permanent plastic flow at either the inner or outer surfaces, the metal will return elastically to its original shape. Stainless steel has a greater elastic spring back than mild steel.
Electric Arc Furnace (EAF) - Melt-down unit which uses the heat of resistance to an electric arc to perform the initial melting of steel.
Electric Furnace Steel - Steel produced in any furnace where heat is generated electrically, almost always by arc.
Electro-Slag Remelting (ESR) - A refining process which uses the heat of resistance of molten slag to an electric arc to remelt an electrode in open atmosphere. ESR results in metals of higher purity, more uniform grain size and improved mechanical properties.
Electrode - An alloy cast into a preliminary shape for later remelting.
Elongation - Increase in length which occurs before a metal is fractured, when subjected to stress. This is usually expressed as a percentage of the original length and is a measure of the ductility of the metal.
Embrittlement - Loss of malleability of a metal due to chemical treatment or physical change.
Engineered Product - Custom components that can be made from a wide range of material including advanced ceramics, carbides, specialty alloys or other specialty materials.
Erosion - The continuous depletion of a material due to mechanical interaction with a liquid, a multi-component fluid, or solid particles carried with the fluid.
Erosion-Corrosion - An accelerated loss of material concerning corrosion and erosion that results from corrosive material interacting with the material.
ESR - See Electro-Slag Remelting
Extrusion - A shaped piece of stainless steel produced by forcing the bloom, bar or rod through a die of the appropriate shape.
Fabricator - An intermediate product producer that purchases and processes material for a specific project.
Fatigue - The phenomenon leading to fracture under repeated or fluctuating stress. Fatigue fractures are progressive, beginning as minute cracks, and grow under the action of fluctuating stress.
Ferrite - The body-centered cubic crystalline phase of iron-based alloys.
Ferritic Stainless Steel - Has a body centered cubic (BCC) structure. These alloys are the chromium stainless steels containing low carbon levels. They are hardenable primarily by cold working, although some will harden slightly by heat treating. Ferritic stainless steels work harden much slower than austenitic stainless steels.
Ferroalloy - 1. Metal products such as ferrochrome, ferromanganese, and ferrosilicon that are commonly used as raw materials to aid various stages in stainless steel production. 2. An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium as a means of adding these elements into molten metal.
Ferrochrome - A common raw material in stainless steel production. This alloy consists of iron and up to 72% chromium.
Ferrous - Related to iron (derived from the Latin ferrum). Ferrous alloys are, therefore, iron-base alloys.
Fine Grain Steel - Steels that resist grain growth over a considerable temperature range, when held at temperature for a reasonable length of time as is customary in heat treatment of steel.
Finishes - The surface appearance of metals after final treatment such as rolling or polishing.
Finishing Facilities - These facilities process semi-finished stainless steel into ready-made forms that can be used by others. Some facilities are rolling mills, pickle lines, tandem mills, annealing facilities, and temper mills.
Flat Wire - A flat Cold Rolled, prepared edge section up to 1/4” wide, rectangular in shape. Generally produced from hot rolled rods or specially prepared round wire by one or more cold rolling operations, primarily for the purpose of obtaining the size and section desired. May also be produced by slitting cold rolled flat metal to the desired width, followed by edge dressing.
Flat-Rolled Stainless Steel (Flat Product) - Category of stainless steel that includes shapes such as sheet, strip, and plate.
Flux - An iron-cleaning agent that consists of limestone and lime. These products react with impurities in the metallic pool and float to the top of the liquid iron.
Foil - Metal with a maximum width of 0.005 inches.
Forging - A form of hot working whereby metal is heated and formed into a desirable shape by pressing or hammering.
Forging Press - Type of hot working in which metal is heated until workable and then pressed into the desired shape by compressing it between a pair of dies.
Forming - A process that brings about a change in the shape of stainless steel by the application of force (i.e. cold forming, hot forming, wire forming).
Fouling - An accumulation of marine organism deposits on a submerged metal surface.
Fracture Test - A test for carbon in which a specimen of metal is drawn off, cooled rapidly in water, and broken with a sledge hammer. The appearance of the metal exposed in the fracture permits a fairly accurate estimate of carbon content or the presence of internal defects.
Free Machining - Grades of stainless steel that, by virtue of their chemistry or processing, are easier to machine into parts.
Frequency and severity - Rating for inclusions and stringers as allowed per each individual grade specification. The quantity of inclusions per square inch equals the frequency. The length of the inclusions per square inch is the severity. The ideal F/S rating would be “0/0.” Each grade of steel has its own F/S.
Fretting Corrosion - Deterioration at the interface of two contacting surfaces under load that is accelerated by their relative motion.
Full Annealing - Heating iron-based alloys above the critical temperature range, holding the temperature above that range for a proper period of time, and then slowly cooling to below the range either in the furnace or in a thermal insulating material.
Galvanic Corrosion - Accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte.
Galvanizing - Coating steel with zinc and tin (principally zinc) for rust proofing purposes.
Gas Carburizing - A method of carburizing carried out in an atmosphere of carburizing gases, including carbon monoxide and hydrocarbons as butane, ethane, methane, and propane.
Gauer Bar - (see edge rolling)
Gauge - Thickness.
General Corrosion - "General corrosion" describes the attack that proceeds in a relatively uniform manner over the entire surface of a metal. Typically, stainless steels do not exhibit general corrosion.
Glaze - A surface coating that seals any open porosity of the bare ceramic surface from contamination or moisture pickup
Grade - The divisions within different types of steel based on carbon content or mechanical properties.
Grain - The individual crystal units in metals. A solid polyhedral (or many sided crystal) consisting of groups of atoms bound together in a regular geometric pattern. In mill practice grains are usually studied only as they appear in one plane: (1) (Direction of) refers to grain fiber following the direction of rolling and parallel to edges of strip or sheets. (2) to bend across the grain is to bend at right angles to the direction of rolling. (3) to bend with the grain is to bend parallel to the directions of the rolling. In steel, the ductility in the direction of rolling is almost always twice that at right angles to the direction of rolling. Grain is the individual crystal units comprising the aggregate structure where the crystalline orientation does not change. The grain boundary is where these individual crystal units meet.
Grain Boundary - Bounding surface between crystals. When alloys yield new phases (as in cooling) grain boundaries are the preferred location for the appearance of the new phase. Certain deterioration such as season cracking and caustic embrittlement, occur almost exclusively at grain boundaries.
Grain Growth - An increase in the average grain size; resulting from some crystals absorbing adjacent ones when the metal is raised to a temperature above that necessary for re-crystallization and kept at that temperature for a sufficient length of time.
Grain Size - The average grain diameter from a random cross-section of material. Grain size is an important property for many alloys, including the titanium commercially pure alloys.
Green Ceramic/ Green Body - A ceramic part in an unfired state
Grinding - A term that implies metal removal similar to fast milling in which the surface is removed by abrasion.
H-Steels - Steels made under specifications that include hardenability tolerance.
Hardenability - The ability of a metal, usually steel, to harden in depth as distinguished from the term “hardness.”
Hardness - A measure of a steel's resistance to indentation: stiffness.
Hardness Test - Hardness testing consists of pressing an indenter into a flat surface under a perfectly controlled load, then measuring the dimension of the resulting indentation. The three methods most commonly used for stainless steel are the Rockwell B, Rockwell C and Vickers tests. The higher the number, the harder the material.
HARP - An abbreviation for "hot rolled annealed and pickled."
Heat - Term referring to batch of refined stainless steel; a charged oxygen or electric furnace full of stainless steel. A heat of stainless steel can be used to cast several slabs, billets, or blooms.
Heat Treatment - Altering the properties of stainless steel by subjecting it to a series of temperature changes. To increase the hardness, strength, or ductility of stainless steel so that it is suitable for additional applications.
Heat-Affected Zone (HAZ) - The part of a metal that is not melted during cutting, brazing, or welding, but whose microstructure and physical properties are altered by these processes.
Hermetic Seal - Airtight seal
High Temperature Alloy (superalloy) - Alloy that can withstand very hot operating environments – up to 2000°F (1093°C) for some alloys – and attendant corrosion and oxidation problems.
Hot Band (Hot-Rolled Stainless Steel) - Stainless steel that has been rolled on a hot-strip mill. It can be sold directly to customers or further processed into other finished products.
Hot Forming - Hot forming operations are used widely in the fabrication of stainless steel to take advantage of their lower resistance to shape change. High temperature reduces their yield strengths, and this results in a marked lowering of the force that is required to bring about plastic movement or flow from one shape to another. (hot rolling, hot stretching, etc.)
Hot Rolling - A method of hot working that reduces the cross-sectional size of a metal bar or coil by passing it between a series of rolls while the material is hot.
Hot Working - The permanent deformation of metal accomplished by applying mechanical forces to the heated metal’s surface.
Hydrogen Embrittlement - The absorption of hydrogen by a metal resulting in a loss of ductility.
Hydrogen Stress Cracking - Cracking of a metal resulting from the combination of hydrogen and tensile stress.
Hydrogen-Induced Cracking - Stepwise internal cracks that connect adjacent hydrogen blisters on different planes in the metal, or to the metal surface.
IBS - Ion Beam System. Equipment to apply a coating to a substrate by way of ion beam.
Impact Test - Impact testing is used to measure the toughness of a material, corresponding to the energy necessary to cause fracture under shock loading. Low toughness is generally associated with brittle shear fracture and high toughness with ductile plastic tearing.
Ingot - An initial cast form that results from a molten alloy being poured into an ingot mold. Remelted alloys also are called ingots.
Injection Molding - A part-forming process in which metallic or ceramic powders, mixed with a binder, are pushed into a custom mold to make intricate parts. The parts may have irregular features on all three axes.
Integrated Mills - Facilities that combine all the stainless steel making facilities from melt shop through hot rolling and cold finishing, to produce mill products.
Intergranular Corrosion - Preferential corrosion cracking at or along the grain boundaries of a metal.
Intergranular Stress Corrosion Cracking - Stress corrosion cracking in which the cracking occurs along grain boundaries.
Iron Ore - A mineral that contains enough iron to be a factor in stainless steel production.
Iron-Based Superalloys - These alloys are at the highest end of the range of temperature and strength. Additives such as chrome, nickel, titanium, manganese, molybdenum, vanadium, silicon, and carbon may be used. These superalloys are also referred to as “super chrome stainless steels.”
Leveling Line - A machine that smoothes any physical deficiencies in the sheet before it is shipped to the customer.
Life Cycle Costing - An accounting method of costing where expenses are allocated over the life of the product. Life cycle costs are often lower for stainless steel than for alternatives despite a higher initial outlay, because stainless products generally last longer and require little maintenance.
Light-Gauge Stainless Steel - A very thin sheet of stainless steel that has either been temper rolled or passed through a cold reduction mill.
Line Pipe - A pipe extending over long distances that transports oil, natural gas, and other fluids.
Long Product - Product made into bar, rod, wire or billet, rather than a flat form.
Loss Factor - This is the product of the Dielectric Loss and the Dielectric Constant of a dielectric material.
Low Carbon Steels - Contain from 0.10% to 0.30% carbon and less than 0.60% manganese. The product of basic oxygen, Bessemer, open hearth or electric processes.
Machining - The cutting away of the surface of metal by means of power-driven machinery. Free-machining stainless steels are easier to machine, extending tool life and improving throughput.
Magnetic Alloys - Alloys that have special magnetic properties.
Malleability - The property that determines the ease of deforming a metal when the metal is subjected to rolling or hammering. The more malleable metals can be hammered or rolled into thin sheet more easily than others.
Martensite - A hard supersaturated solid solution of iron characterized by an acicular (needle-like) microstructure.
Martensitic Stainless Steel - Has a body centered tetragonal (BCT) structure. These alloys are chromium stainless steels with medium to high carbon levels. They work harden slowly in the annealed (soft) condition but can be heat-treated to very high tensile strengths.
Mechanical Properties - Those properties that reveal the reaction, either elastic or plastic, of a metal to an applied stress. Tensile strength, yield strength, elongation, reduction of area, hardness, impact strength, and bendability are mechanical properties.
Melting Range - The range of temperature in which an alloy melts is the range between solidus and liquidus temperatures.
Metal matrix Composite - Formed by infiltrating a ceramic preform with a molten metallic product. Once solidified, the resulting product combines the best features of ceramics and metals.
Mill form - Shapes manufactured by traditional rolling or drawing operations, such as rounds, squares, hexagons and rectangles.
Mill Products - Generally mill forms of sheet, strip, plate, bar rod and semi-finished forms.
MIM - Metal Injection Moulding. Very similar to CIM, this technique uses specially prepared metal powders to make metal components
Modulus of Rigidity - Of a material suffering shear, the ratio of the intensity of the shear stress across the section to the shear strain, i.e., to the angle of distortion in radians; expressed in pounds or tons per square inch.
Molybdenum (Mo) - An alloying element that enhances corrosion resistance along with chromium in stainless steels.
Nickel (Ni) - An alloying element used in stainless steels to enhance ductility and corrosion resistance.
Nickel-Based Superalloys - Alloy metal produced for high-performance, high-temperature applications such as nickel-iron-chrome alloys and nickel-chrome-iron alloys.
Nonferrous Metals - Non-iron based metal, including copper, aluminum and their alloys (e.g., brass and bronze).
Oil Country Tubular Goods (OCTG) - Category of pipe products used by petroleum exploration customers. Labels bearing OCTG are applied to casting, drill pipes, oil well tubing, etc.
Ore - An iron-containing material used primarily in the melting furnace.
Oscillating - A method of winding a narrow strip of stainless steel over a much wider roll. This allows for more stainless steel per roll and allows the customer to have longer processing runs.
Oxidation - Rust or corrosion due to exposure to oxygen.
Passivation - When exposed in air, stainless steels passivate naturally (due to the presence of chromium). But the time required can vary. In order to ensure that the passive layer reforms rapidly after pickling, a passivation treatment is performed using a solution of nitric acid and water.
Passive - A characteristic condition of stainless steels which impedes normal corrosion tendencies to the point where the metal remains virtually un-attacked — hence passive to its environment.
PBN - Pyrolytic Boron Nitride
Physical Properties - Those properties familiarly discussed in physics, exclusive of those described under mechanical properties; for example, density, electrical conductivity, co-efficient of thermal expansion. This term often has been used to describe mechanical properties, but this usage is not recommended (see Mechanical Properties).
Pickling or chemical milling - A process that removes surface scale and oxidation products by immersion in a chemically active solution, such as sulfuric or hydrochloric acid. Used in titanium to help remove alpha case and/or surface imperfections.
Pickling Paste - A commercially available product that performs the pickling function when used on the surface of stainless steel.
Piezoelectric - When mechanical pressure is applied to one of these materials, the crystalline structure produces a voltage proportional to the pressure. Conversely, when an electric field is applied, the structure changes shape producing dimensional changes in the material. The amount of deformation is proportional to the applied electric field and the d33 coefficient of the material
Pipe - Term that originally defined a tube used to transport fluids or gases. Often now, pipe and tube are used interchangeably.
Pitting - Localized corrosion (in the form of pits) of a metal surface that is confined to a small area.
Plate - Product form in which the metal measures more than 10 inches wide and 3/16 in. thick or more.
Poisson’s Ratio - When a sample of material is stretched in one axis, it tends to get thinner in the other two axes. Poisson's ratio (?) is a measure of this tendency. It is defined as the ratio of the strain in the direction of the applied load to the strain normal to the load. For a perfectly incompressible material, the Poisson's ratio would be exactly 0.5.
Poling - The application of a high electric field resulting in dipole alignment within the material.
Porosity - The proportion of the non-solid volume to the total volume of material.
Postweld Heat Treatment - Heating and cooling a weldment in such a way as to obtain desired properties.
Powder Alloys/Powder Metals - Produced by means of a high-pressure gas to break up a molten metal stream into droplets, which rapidly solidify into metal powder particles. These particles are then consolidated to create bar, coil or other mill forms. Powder metal mill forms offer superior performance and uniformity to cast or wrought mill forms.
Powder Metallurgy - The art of producing metal powders and of utilizing metal powders for the production of massive materials and shaped objects.
Precipitation Hardening (PH) - A small category of stainless steels resembling martensitic stainless steels that have great strength and hardness due to heat treatment.
Premium Melting or Vacuum Melting - A process in which raw materials are first melted within a vacuum. The metal is often remelted again under a vacuum to produce very pure alloys. Together, these processes result in tighter control of a metal’s chemistry and greater consistency in structural properties such as toughness, ductility, and fatigue strength.
Process Annealing - In the sheet and wire industries, a process by which a ferrous alloy is heated to a temperature close to, but below, the lower limit of the transformation range and is subsequently cooled. This process is applied in order to soften the alloy for further cold working.
PZT - a) Piezoelectric Transducer b) Lead Zirconate Titanate, Pb(Zr,Ti)O3
Quench Hardening (Steel) - A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite.
Quenching - In the heat treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil or water. In the case of most copper base alloys, quenching has no effect other than to hasten cooling.
RBSN - Reaction Bonded Silicon Nitride
Reinforcing Bar (Rebar) - A commodity-grade stainless steel used to reinforce concrete in highway and building structures.
Remelting - The process whereby previously melted electrodes are remelted into higher quality ingot.
Residuals - The impurities remaining in mini-mill stainless steels resulting from the wide variety of metals entering the process.
Reversing Mill - A stand of rolls that passes stainless steel back and forth between the rolls in order to reduce the stainless steel sheet or plate. The distance between the rolls is reduced after each pass.
Rockwell Hardness (Test) - A standard method for measuring the hardness of metals. The hardness is expressed as a number related to the depth of residual penetration of a steel ball or diamond cone (“brale”) after a minor load of 10 kilograms has been applied to hold the penetrator in position. This residual penetration is automatically registered on a dial when the major load is removed from the penetrator. Various dial readings combined with different major loads, give “scales” designated by letters varying from “A” to “H”; the “B” and “C” scales are most commonly in use.
Rod - Semi-finished product, formed into coils, from which wire is made.
Scale (Scale Removal) - The oxide that forms on the surface of stainless steel, after exposure to high temperature.
Seamless Pipe - Pipe produced from a solid billet that is heated and rotated under pressure. This rotating pressure creates a hole in the middle of the billet, which is then formed into a pipe by a mandrel.
Semi-Finished Stainless Steel - Stainless steel products such as blooms, billets, or slabs that are then rolled and processed into beams, bars, wire, etc.
Sensitization - The phenomenon in austenitic stainless steels that causes a change to occur in the grain boundaries when heated in the general range of 850 to 1475 degrees F. This change destroys the passivity in these locations.
Service Center - An operation that buys metal, stores it (often processing it in some way), and then sells it in a slightly different form than it was purchased from the producing mills.
Shape Correcting - Levelers, edge trimmers, and temper mills reshape processed stainless steel to meet customers’ specifications. Reshaping is needed from processes that cause deformities in the stainless steel.
Shapes - Bar or coil product that is passed between custom dies and rolls to form half-round, hexagonal, square and other more intricate shapes.
Shearing - Trimming of sheet strip to make the edges parallel.
Sheet - A stainless steel flat rolled product that is under 3/16 inch in thickness and 24 inches or more in width.
Shot Blasting - Blast cleaning using stainless steel shot as the abrasive. Not recommended for stainless steel. Glass beads should be used.
Sigma Phase - An extremely brittle Fe-Cr phase that can form at elevated temperatures in austenitic and ferritic stainless steels.
Sintering - The heating process that transforms a green ceramic and densifies the material into a stronger state.
Six Sigma - Statistical measurement of tightly controlled processes with the goal of generating only 3.4 defects per million opportunities.
Slab - A common type of semi-finished stainless steel usually measuring 6-10 inches thick by 30-85 inches wide and averaging 20 feet long. After casting, slabs are sent to a strip mill for rolling into sheet and plate products.
Slag - A layer formed on the surface of the molten metal which serves as a reservoir for the various metallic oxides formed during melting and refining.
Slitting - Cutting a sheet of stainless steel into narrower strips.
Solution Heat Treatment - Heating a metal to a high temperature and maintaining it long enough for one or more constituents to enter the solid solution. The solution is then cooled rapidly to retain the constituents within.
Solution treating and aging - Strengthening mechanism used in titanium alpha-beta alloys as well as PH stainless alloys and many nickel-based super alloys. For titanium alloys, the solution treating temperature that is normally 50°-150° F below the beta-transus of the material and, after water quenching, the material is aged at 800°-1200°F.
Solvent Cleaning - The removal of contaminants such as oil, grease, dirt, salts, etc., by cleaning with a solvent, steam, vapor, alkali or emulsion.
Specialty alloys - Alloys composed of two or more chemical elements that typically perform under very rigorous service conditions or that have special electrical, thermal, magnetic, corrosion resistant, or mechanical properties. Metals with distinct chemical and physical properties. These alloys are produced for specific applications and are considered to be on the low end of superalloys.
Specialty Steel - Category of steel that includes high strength, stainless and tool steels.
Specialty Tube - A wide variety of high quality, specialized tubular products. It is usually found in the automotive and agricultural industries, construction equipment, hydraulic cylinders, etc.
Stainless steel - Grades of steel with more than 10% chromium and often with other alloying elements to resist corrosion, vary strength characteristics, and facilitate fabrication into parts.
Steckel Mill - A reversing stainless steel sheet reduction mill with heated coil boxes at each end. Stainless steel sheet or plate is sent through the rolls of the reversing mill and coiled at the end of the mill, reheated in the coil box, and sent back through the Steckel stands and recoiled. By reheating the stainless steel prior to each pass, the rolls can squeeze the stainless steel thinner per pass and impart a better surface finish.
Strain - The amount of elongation, force or compression that occurs in a metal at a given level of stress. Generally in terms of inches elongation per inch of material.
Strength - The ability of stainless steel to oppose applied forces when considering resistance to stretching, forming, compressing, etc.
Stress Corrosion Cracking (SCC) - Slowly developing cracks that form in stainless steel due to mechanical stress and exposure to a corrosive environment.
Stress Relief - Low temperature annealing for removing internal stresses, such as those resulting in a metal from work hardening or quenching.
Stress Relieving - Reducing residual stresses by heating.
Strip - Thin, flat steel that resembles hot-rolled sheet but is normally narrower and is produced to more closely controlled thickness.
Structurals - An architectural stainless steel product group that includes I-beams, H-beams, wide-flange beams and sheet piling. These products are used in multi-story buildings, bridges and vertical highway supports.
Superalloy (high-temperature alloy) - Alloy that can withstand very hot operating environments – up to 2000°F (1093°C) for some alloys – and attendant corrosion and oxidation problems.
Tailored Blanks - A section of sheet stainless steel that is cut to the manufacturer’s requirements. Excess stainless steel is trimmed away to save transportation costs and is ready for the stamper to shape with a die press.
Tandem Mill - A cold-rolling mill that gives greater strength, a more uniform and smoother surface, and a reduced thickness to the stainless steel sheet. This mill rolls stainless steel through a series of rolls, to achieve a desired thickness and surface quality.
Tempered (Temper) - A term applied to cold worked material such as strip, sheet and wire, expressing the range of mechanical properties as produced by the cold work (as is quarter hard, half hard, etc.).
Tempering (drawing) - A process of reheating quench-hardened or normalized steel to a temperature below the transformation range and then cooling at any rate desired. The primary purpose of tempering is to impart a degree of plasticity or toughness to the steel to alleviate the brittleness of its martensite.
Tensile Strength (ultimate strength) - The breaking strength of a material when subjected to a tensile (stretching) force. Usually measured by placing a standard test piece in the jaws of a tensile machine, gradually separating the jaws, and measuring the stretching force necessary to break the test piece. Tensile strength is commonly expressed as pounds (or tons) per square inch of original cross section.
Thermal Downshock - Thermal downshock is the name given to cracking resulting from rapid temperature change. It occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress overcomes the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the component to catastrophically fail.
Thin wall tubing - Tubes with wall thickness that can be as thin as .005 inches (.127 mm) yet remain structurally sound in many environments. Such thin walls minimize the weight of the tube.
Titanium - Structural metal that offers excellent corrosion and erosion resistance, superior strength-to-weight ratios, and high heat transfer efficiency.
Titanium alpha alloys - Titanium alloys that are either pure (Commercially Pure Ti) or richer in alpha stabilizing elements.(i.e. Al, Sn, Ga ). These alloys can’t be strengthened by heat treat but have good weldability.
Titanium alpha–beta alloys - Titanium alloys that contain at least one alpha stabilizer and one beta stabilizer. These alloys can be strengthened by solution treating and aging. Titanium 6Al-4V is a very common alpha–beta alloy.
Titanium beta alloys - Titanium alloys that are richer in beta stabilizing elements (i.e. Mo, V). These titanium alloys have great forgeability and high hardenability but are higher in density.
Titanium-Based Superalloys - Lightweight, corrosive-resistant alloys suitable for high temperatures. These alloys have been used for airplane parts. Titanium alloys can blended with aluminium, iron, vanadium, silicon, cobalt, tantalum, zirconium, and manganese.
Tolerances - Measures the allowable difference in product specifications between what a customer orders and what the manufacturing company delivers.
Ton - Unit of measure for stainless steel scrap and iron ore. Gross Ton: 2,240 pounds. Long (net) Ton: 2,240 pounds. Short (net) Ton: 2,000 pounds. Normal unit of statistical raw material input and stainless steel output in the United States. Metric ton: 1,000 kilograms. (2,204.6 pounds or 1.102 short tons).
Tool steel - Alloys of iron used in making tools and dies that offer strength and fabrication qualities. Typically, tool steels contain carbon, manganese, chromium, tungsten and other alloying elements.
Toughness - Property of resisting fracture or distortion. Usually measured by impact test, high impact values indicating high toughness.
Trepan - To remove a cylindrical core in a metal bar, creating a hollow bar.
Tungsten (W) - A gray metal with high tensile strength. It is ductile, malleable, and resistant to atmospheric elements and all acids except strong alkalis.
Tungsten carbide - Advanced material that is very hard and wear resistant, making it suitable for severe service applications such as cutting and grinding tools.
Ultimate strength - The maximum load divided by the original cross-sectional area of a sample, resulting in the maximum stress a material can sustain without fracture.
Ultrasonic inspection - A particular type of inspection in which internal and external defects are located by studying the travel pattern of sound waves sent through the material.
Vacuum Annealing - Annealing that is done in a vacuum to prevent the alloy from reacting with oxygen while at high temperatures. This process is particularly important for titanium alloys, where alpha-case can form at high temperatures when in the presence of oxygen found in air furnaces. This type of annealing can also be used to reduce hydrogen content in titanium.
Vacuum Arc Remelting (VAR) - Refining process in which a previously melted electrode is remelted under a vacuum to produce a finer, more uniform grain structure in metals.
Vacuum Induction Melting (VIM) - Manufacturing process in which raw materials are melted within a vacuum using the heat from an induced magnetic field. VIM ensures tight control of a metal’s chemistry and more consistent structural properties.
Vacuum Oxygen Decarburization (VOD) - A refinement of stainless steel that reduces carbon content. Molten, unrefined stainless steel is heated and stirred by an electrical current while oxygen enters from the top. Many undesirable gases escape from the stainless steel and are evacuated by a vacuum pump. Alloys and other additives are then mixed in to refine the molten stainless steel further.
Vanadium (V) - A grey metal that is normally used as an alloying agent for iron and stainless steel. It is also used as a strengthener of titanium-based alloys.
VAR - See Vacuum Arc Remelting
VIM - See Vacuum Induction Melting
Wire - Finished product that is shipped in coils, can vary in shape, but is typically under one inch (25.4 mm) in diameter.
Work Hardening - Increase in resistance to deformation (i.e. in hardness) produced by cold working.
Workability - The characteristic or group of characteristics that determine the ease of forming a metal into desired shapes.
Yield Strength (YS) - The stress (load/area) at which the metal changes from elastic to plastic in behavior, i.e., takes a permanent set.
Young’s Modulus - Young's modulus (or elastic modulus) is a measure of the stiffness of a given material. It is defined as the limit for small strains of the rate of change of stress with strain. This can be experimentally determined from the slope of a stress-strain curve created during tensile tests conducted on a sample of the material. Young's modulus is named after Thomas Young the English physicist, physician, and Egyptologist
Zirconium (Zr) - A strong, ductile metal obtained by the chemical processing of zircon-bearing sands. It has good corrosion resistance at high temperatures and is used as a structural material in nuclear reactors and cladding material for uranium.
ZTA - Zirconia Toughened Alumina