AQL Acceptable Quality Level—a quality level established on a prearranged system of inspection using samples selected at random.

alloy—1) a homogeneous substance composed of two or more elements at least one of which is a metal (for example, cast iron contains iron, carbon and silicon) which generally exhibits metallic properties that differ from those of its component elements. 2) In minting, the base metal added.

alloying—adding elements to an alloy (other than the elements that usually comprise it) or to a metal to change its properties.

anneal—generally a heat treatment to “soften” metals; heating to and holding at a suitable temperature and then cooling at a suitable rate for such purposes as reducing hardness, improving machinability, facilitating cold working, producing a desired microstructure, or obtaining desired mechanical, physical, or other properties. When applicable, more specific terms should be used; i.e., ferritizing anneal–the process of producing a predominantly ferrite matrix in a cast iron alloy through an appropriate heat treatment. Annealing usually reduces stresses, but if the heat treatment is solely for such relief, it should be designated as stress relieving.

as-cast condition—casting without subsequent heat treatment.

binder—the bonding agent used as an additive to mold or core sand to impart strength or plasticity in a “green” or dry state.

blast cleaning—cleaning sand or oxide scale from castings by impinging the surface with abrasive particles moving at high speed. Abrasives are carried by a gas or liquid or are thrown centrifugally by a wheel. Small, irregular particles of steel or iron are used as the abrasive in grit blasting, sand in sandblasting, and steel or iron balls in shot blasting. See also air blasting, airless blast cleaning.

blast furnace—a shaft furnace in which solid fuel is burned with an air blast to smelt ore in a continuous operation.
The raw materials are charged at the top, and the molten metal and slag that collect at the bottom are tapped out at intervals. Where the temperature must be high (such as in the production of pig iron), the air blast is preheated. Where the temperature can be lower (such as in the smelting of copper, lead and tin ores), preheating of the blast is not required, and a smaller furnace is economical.

castability—(1) a combination of liquid-metal properties and solidification characteristics that promotes accurate and sound final castings. (2) The relative ease with which a metal flows through a mold or casting die. 

chaplet—a small metal insert or spacer used in molds to provide core support during the casting process.

charge—a given weight of metal introduced into the furnace.

chill (noun)—a metal insert in the sand mold used to produce local chilling and equalize rate of solidification throughout the casting.

cope—the top half of a horizontally parted mold.

core—a sand or metal insert in a mold to shape the interior of the casting or that part of the casting that cannot be shaped by the pattern.

core box/corebox—the wooden, metal or plastic tool used to produce cores.

crucible—a pot or receptacle made of refractory materials such as high temperature resisting alloys, graphite, alundum, magnesia, or silicon carbide, bonded with clay or carbon, and used in melting or fusion of metals. This term is sometimes applied to pots of cast iron, cast or wrought steel. 

cupola—a cylindrical, straight shaft furnace (usually lined with refractories) for melting metal in direct contact with coke by forcing air under pressure through openings near its base.

cure—to harden.

die—a metal form used as a permanent mold for die casting or for a wax pattern in investment casting.

draft—taper on the vertical sides of a pattern or corebox that permits the core or sand mold to be removed without distorting or tearing of the sand. 

drag—the bottom half of a horizontally parted mold.

fatigue—tendency for a metal to break under conditions of repeated cyclic stressing considerably below the ultimate tensile strength.

feeding—pouring additional molten metal into a freshly poured mold to compensate for volume shrinkage while the casting is solidifying; the continuous supply of molten metal, as from a riser, to the solidifying metal in the casting; keeping risers open by manipulation of feeding rods.

fillet—a concave corner piece used to radius a corner on patterns and core boxes, a radiused joint replacing sharp inside corners. May be of wax, plastic, leather or wood. Fillets are used to avoid shrinkage cracks and eliminate concentrations of stress. A struck fillet is one that is dressed to shape in place, usually of wax. A planted fillet is one made separately and affixed in place. Fillets used at reentrant angles in cast shapes lessen the danger of cracks and avoid fillet shrinkage.

flask—a rigid metal or wood frame used to hold the sand of which a mold is formed and usually consisting of two parts, cope and drag.

foundry returns—metal (of known composition) in the form of gates, sprues, runners, risers and scrapped castings returned to the furnace for remelting.

gas porosity—a condition existing in a casting caused by the trapping of gas in the molten metal or by mold gases evolved during the pouring of the casting.

gate (ingate)—that portion of the runner in a mold where molten metal enters the casting or mold cavity; sometimes applied to entire assembly of connected channels, to the pattern parts which form them or to the metal which fills them, and sometimes is restricted to mean the first or main channel. Other gates: bottom, branch, bypass, finger, horn, horseshoe, knife, lap (kiss, touch, pressure), parting, pencil, reverse horn gate, ring, shower (pencil gate, pop gate), skim, slot, step, strainer, top, vertical, wedge, whirl (swirl).

geometry—in metalcasting, the dimensions of the sizes and shapes of patterns, cores and castings.

green sand mold—a mold composed of moist prepared molding sand that is not dried before filling the mold with molten metal. 

heat treatment—a combination of heating and cooling operations timed and applied to a metal or alloy in the solid state in a manner that will produce desired properties. (ASTM standards have been created for specific for alloy and temper designations for subdivisions of T tempers, ASTM.org) Heating for the sole purpose of hot working is excluded from the meaning of this definition.

high-pressure die casting—(HPDC) injects molten metal at a high speed and pressure into the mold cavity (alloys include: aluminum, magnesium, steel, zinc, etc.). Ideal process for high-volume casting quantities with tight tolerances.

hot tear—irregularly shaped fracture in a casting resulting from stresses set up by steep thermal gradients within the casting during solidification.

induction furnace—an alternating current (AC) electric furnace in which the primary conductor is coiled and generates a secondary current by electromagnetic induction which heats the metal charge. See channel induction furnace, coreless induction furnace.

ingot—a mass of metal cast to a convenient size and shape for transporting, remelting or hot working.

inclusion—Particles of slag, refractory materials, sand or deoxidation products trapped in the casting during pouring solidification.

inversion casting—(1) the metal is fed through a bottom feeder; the mold being inverted for pouring. (2) The mold is directly atached to the electric furnace in which the metal is melted in a reducing atmosphere, so no slag is formed. On inverting the furnace, the metal runs into the mold. There are no heavy feeders and oxidation is prevented.

investment casting process—the coating of an expendable pattern with a ceramic material so that it forms the surface of the mold that contacts the molten metal when the pattern is removed, and the mold is poured.

ladle—a crucible or iron vessel lined with refractory material for conveying molten metal from the furnace and pouring it into the mold.

locating surface—a casting surface to be used as a basis for measurement in making secondary machining operations.
lost foam casting process (LFC)—a metalcasting process in which a foam pattern is replaced by molten metal in a flask filled with loose sand to form a casting. LFC uses a cavity-less mold with the foam pattern remaining in the mold during pouring. The foam pattern is replaced by molten metal, producing the casting. 

mechanical properties—Those properties of a material that reveal the elastic and inelastic properties when force is applied. This term should not be used interchangeably with “physical properties.”

mold—Normally consists of a top and bottom form, made of sand, metal or any other investment material. It contains the cavity into which molten metal is poured to produce a casting of definite shape.

nobake process—molds/cores produced with a resin-bonded air-setting sand. Also known as the airset process because molds are left to harden under normal atmospheric conditions.

parting line—the line showing the separation of the two halves of the mold.

pattern—the wood, metal, foam or plastic shape used to form the cavity in the sand. A pattern may consist of one or many impressions and would normally be mounted on a board or plate complete with a runner system.

permeability—The property of a mold material to allow passage of mold/core gases during the pouring of molten metal.

pig iron—blocks of iron to a known metal chemical analysis that are used for melting (with suitable additions of scrap, etc.) for the production of ferrous castings.

porosity—holes in the casting due to: gases trapped in the mold, the reaction of molten metal with moisture in the molding sand, or the imperfect fusion of chaplets with molten metal.

quench—rapid cooling. When applicable, the following more specific terms should be used: direct quenching, fog quenching, hot quenching, interrupted quenching, selective quenching, spray quenching and time quenching.

refractory—heat-resistant ceramic material.

reject rate—ratio of the number of parts scrapped to the total number of parts manufactured, expressed as a percentage.

riser—an opening in the top of a mold that acts as a reservoir for the molten metal and prevents cavities in the casting as it contracts on solidification. It allows gases to escape as the metal rises in the mold and indicates when the mold is full. 

runner (crossgate)—the set of channels in a mold through which molten metal is poured to fill the mold cavity. The system normally consists of a vertical section (downgate or sprue) to the point where it joins the mold cavity (gate) and leads from the mold cavity through vertical channels (risers or feeders) 

recovery rate ratio—ratio of the number of saleable parts to the total number of parts manufactured, expressed as a percentage. as torch.

scrap—(a) Any scrap metal melted (usually with suitable additions of pig iron or ingots) to produce castings; (b) reject castings.
shakeout—the process of separating the solidified casting from the mold material.

shrinkage—contraction of metal in the mold during solidification. The term also is used to describe the casting defect, such as shrinkage cavity, which results from poor design, insufficient metal feed or inadequate feeding.

slag—a fused nonmetallic material that protects molten metal from the air and extracts certain impurities from the melt. Can be a product resulting from the action of a flux on the oxidized non-metallic constituents of molten metals. It is skimmed off prior to tapping the heat.

slurry—a flowable mixture of refractory particles suspended in a liquid.

sprue (downsprue, downgate)—the channel, usually vertical, connecting the pouring basin with the skimming gate, if any, and the runner to the mold cavity, all of which together is called the gating system. In top-poured castings, the sprue may also act as a riser. Sometimes used as a generic term to cover all gates, risers, etc. returned to the melting unit for remelting.

tensile strength—the maximum stress in uniaxial tension testing which a material will withstand prior to fracture. The ultimate tensile strength is calculated from the maximum load applied during the test divided by the original cross-sectional area. In the case of ductile materials, fracture is preceded by elongation and consequent reduction in cross-sectional area.

test bar—standard specimen bar designed to permit determination of mechanical properties of the metal from which it was poured.

tolerance—allowable deviation from a standard.

tooling—manufacturing aids (i.e., tools, dies, fixture, gages, jigs, patterns and molds to aid the manufacturing process.
vent—an opening or passage in a mold or core to facilitate escape of gases when the mold is poured.

warpage —(1) deformation other than contraction that develops in a casting between solidification and room temperature. (2) Distortion occurring during annealing, stress-relieving, and high- temperature service.

yield—casting yield, the percentage of quality, degated castings produced in relation to the total amount of metal melted and poured. Yield = weight of clean casting ÷total weight of metal poured into mold x 100% (i.e., if 50 lbs. of quality, degated castings result from pouring 100 lbs. of metal, the casting yield is 50 lbs. ÷ 100 lbs. x 100% = 50%.)