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 a abrasives in cleaning castings.
Abrasion Resistance: Degree of resistance of a material to abrasion or wear.
Accelerator: A substance that hastens a reaction usually acting as a catalyst; as used in sand additive resins.
Acid: A term applied to slags, refractories and mineral containing a high percentage of silica.
Acid Brittleness (Pickling 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 steelmaking method using an acid refractory lined furnace. Neither sulfur nor 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 precision castings 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.
Additive: Any material added to molding sand for reasons other than bonding; e.g., seacoal, pitch, graphite, cereals.
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
AFS Tests: A number of standard tests determined by American Foundrymen’s Society to evaluate molding and core sands.
Aging: A change in properties that generally occurs slowly in atmospheric temperature and more rapidly (termed artificial aging) in higher temperatures.
Airblasting: A cleaning operation, as cleaning sand from molds.
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 Quenching (Normalizing): Cooling of alloys in air from above the transformation range.
Air Scale: Scale left on ferrous metal in processing usually from heating in presence of air.
Alkaline Derusting: An electrical process for derusting steel, cast iron and other ferrous alloys without using heat.
Alloy: 1. 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, 2. In minting, the base-metal added.
Alloy Steel: Steel containing significant quantities of alloying elements other than carbon and the commonly accepted amounts of manganese, silicon, sulfur and phosphorus.
Allowance (Tolerance): In a foundry, the clearance specified; difference in limiting sizes, as minimum clearance or maximum interference between mating parts, as computed arithmetically.
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 alternatingly in opposite directions.
Ambient Temperature: Temperature of the surrounding air.
Ambient Air: 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.
Annealing: A process involving heating and cooling applied in order to alter mechanical or physical properties, particularly to reduce hardness. Also applied to treatments intended to produce a definite microstructure or remove gases. Any process of annealing will usually reduce stresses, but if the treatment is applied for the sole purpose of such relief, it should be designated as stress relieving.
Anticarburizing Compounds: Compounds applied to metallic surfaces to prevent surface carburization.
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.
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.
Artificial Aging: An aging treatment at above room temperature. See Precipitation Heat Treatment and compare with aging, natural.
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.
Atmosphere, Furnace: Gases with which metal is in contact during melting or heat treating.
Atmosphere, Neutral: Furnace atmosphere made up of an inert gas as argon or where the products of combustion are neither oxidizing nor reducing in contact with the metal being heated.
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 product 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: Solid solution of one or more elements in face centered cubic iron.
Austenitic Steels: Any steel containing sufficient alloy to produce a stable austenitic (gamma iron) crystalline structure at ambient temperatures.