Glossary and Terms of the Foundry Industry

SFSA: Glossary of Terms - A

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AAR: See Association of American Railroads for association address information.
Abrasion: The displacement and/or detachment of metallic particles from a surface as a consequence of being exposed to flowing solids, fluids or gases.
Abrasion Resistance: Degree of resistance of a material to abrasion or wear.
Abrasive Wear: The displacement and / or detachment of metallic particles from a surface as a consequence of being exposed to flowing fluids or gases.
Abrasives: Materials 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.
Ac1: The temperature at which austenite begins to form on heating.
Ac3: In hypoeutectoid steel, the temperature at which transformation of ferrite into austenite is completed upon heating.
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.
Acid: 1) A solution or liquid with a pH less than 7, 2) term applied to slags, refractors, and minerals containing a high percentage of silica.
Acid Brittleness (Picking Brittleness): Lack of ductility, induced in steel when it is pickled in dilute acid to remove scale - commonly attributed to the absorption of hydrogen.
Acid Embrittlement: Embrittlement during pickling due to absorption of hydrogen.
Acid Process: A steel making method using an acid refractory-lined (usually silica) furnace. Neither sulfur or phosphorus is removed.
Adapti Investment Casting Process: A lost wax process employing one of three methods; centrifugal, vacuum or gravity-pouring casting.
Adeline Steelmaking Process: Method of producing a precision casting of steel or steel alloys using aluminolthermic process and lost wax, followed by centrifugal action.
Addition Agent: 1) Any material added to a charge of molten metal in bath or ladle to bring alloy to specifications, 2) reagent added to plating bath.
Aecm, Ae1, and Ae3: Equilibrium transformation temperatures in steel.
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.
AFS: See American Foundrymen's Society for association address information.
AFS Tests: A number of standard tests determined by American Foundrymen's Society to evaluate molding and core sands.
Age Hardening: Hardening by aging, usually after rapid cooling or cold working.
See also Precipitation Hardening
Aging: A change in properties of metals and alloys which occurs slowly at room temperature and will proceed rapidly at higher temperatures. The change in properties is often, but not always, due to a phase change (precipitation), but never involves a change in chemical composition of the metal or alloy.
See also Age Hardening
See Precipitation Hardening
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-Hardening Steel: A steel containing sufficient alloy to fully harden during cooling in air. Typically this term is restricted to steels being able to harden in sections of about 2 in. (51 mm) or more.
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.
Alkaline Derusting: An electrical process for derusting steel, cast iron and other ferrous alloys without using heat.
Allowance (Tolerance): In a foundry, the clearance specified; difference in limiting sizes, as minimum clearance or maximum interference between mating parts, as computed arithmetically.
Alloy: A substance having metallic properties and composed of two or more chemical elements of which at least one is metal. Usually possesses qualities different from those of the components.
Alloy Steel: Steel containing significant quantities of alloying elements other than carbon and the commonly accepted amounts of manganese, silicon, sulfur, and phosphorus.
Alpha - ferrite: Body-centered cubic type of pure iron stable below 1670F (910C).
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.
Alternating Stress: Stress produced in a material by forces acting alternating in opposite directions.
Ambient Air: The surrounding air.
Ambient Temperature: Temperature of the surrounding air.
Ames Portable Hardness Tester: The Rockwell penetration method of testing hardness of metals can be made with this tester by applying pressure to the penetrator by screw action.
Analysis Line: In spectrographic analysis, the particular spectral line used in determining the concentration of an element.
Angle Testing: A method of ultrasonic testing using shear waves introduced from the surface of the material at approximately 45 degrees.
Anisotropy: The characteristic of exhibiting different property values in different directions with respect to a fixed reference system in the material.
Annealing: Heating to and holding at a suitable temperature, followed by cooling at a suitable rate to lower the hardness or alter other mechanical or physical properties.
Anticarburizing Compounds: Compounds applied to metallic surfaces to prevent surface carbonization.
AOD: See Argon Oxygen Decarburization
APFIM - Atomic Probe Field Ion Microscopy: An analytical technique in which atoms are ionized by an electric field near a sharp specimen tip. The field then forces the ions to a fluorescent screen which shows an enlarged image of the tip and individual atoms are made visible.
Apparent Contraction: The net contraction of a casting dimension due to true metal contraction, mold wall movement and restraint during solidification and cooling.
Arc Cutting: Using an electric arc to cut 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.
ARD Process: A refinement of the precision casting process, using plastic patterns produced in automatic injection machines.
Argon Oxygen Decarburization (AOD): A secondary refining process in which argon, oxygen and nitrogen are injected into a molten bath of steel. The AOD process improves metal cleanliness and thus gives superior mechanical properties.
Arnold's Fatigue Test: (after John Arnold, Brit. Met.), a test for fractures using 850 cyclic stress reverses per min., recording the number of cycles required to produce fracture.
Artifical Aging: An aging treatment above room temperature.
See Aging and Age Hardening
As Cast (as-cast, u.m.): Referring to metal which has not received finishing (beyond gate removal or sandblasting) or treatment of any kind including heat treatment after casting. Similarly, as drawn, as forged and as rolled. (See Finishing)
ASM: See American Society for Metals for association address information.
ASNT: See American Society for Nondestructive Testing for association address information.
ASTM: See American Society for Testing and Materials for association address information.
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.
Austenite: The face-centered-cubic phase of iron and steel, also referred to as gamma iron. In steel, a solid solution in which gamma iron is the solvent.
Austenite Steel: Any steel containing sufficient alloy to produce a stable austenitic (gamma iron) crystalline structure at ambient temperatures.

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