Glossary of Metal Casting Terms

Acceptable Quality Level (AQL) - A quality level established on a prearranged system of inspecting randomly selected samples.

Age Hardening - After rapid cooling or cold working, the process of increasing hardness and strength and decreasing ductility through aging.

Aging - A change in structure by which a metal or alloy recovers from an unstable condition, resulting in precipitation and a change in physical properties.

Alloy - A substance composed of two or more elements, at least one of which is metal, created to improve the material's properties or lower its cost.

Angularity - The angular relationship of one surface to another; specifically, as it relates to the dimensional tolerance of such features on a casting.

As-Cast Casting - condition without subsequent finishing, including heat treatment.

Backing Sand - The bulk of the sand in the flask; the sand compacted on top of the facing sand that covers the pattern.

Base Metal - Principal metallic material used in an alloy.

Bath - Molten metal on the hearth of a furnace, in a crucible or in a ladle

Bentonite - A colloidal, clay like substance used as a binder in metalcasting sand mixtures where extra green or hot strength is required.

Binder - The bonding agent used as an additive to mold or core sand to impart strength or plasticity in a dry state.

Blast Ceaning - Removal of sand or oxide scale from castings by impinging action of sand, metal shot or grit projected under pressure.

Bottom Pouring - Filling a mold cavity from a low point by means of gates from the runner.

Brinell Hardness - A test for determining the hardness of a material by forcing a ball of specified diameter into it under a specified load; results in the Brinell hardness number (Bhn).

Bull Ladle - A large container for transporting and pouring of molten metal. Frequently used to designate a transfer ladle.

Burn-on Sand - Sand adhering to the surface of the casting that is extremely difficult to remove.

Castability - A combination of liquid metal properties and solidification characteristics that promotes accurate and sound castings; the ease with which metal flows through a mold or 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 - A metal insert in the sand mold used to produce local chilling and equalize rate of solidification throughout the casting.

Clamp - A device for holding together parts of a mold, flask, corebox, etc.

Cleaning - Removal of runners, risers, flash, surplus metal and sand from a casting.

Cope - The top half of a horizontally parted mold.

Core - A sand or metal insert in the mold to shape the interior of the casting or that part of the casting that cannot be shaped by the pattern.

Core Assembly - A substructure made from a number of cores.

Core Box - The wooden, metal, or plastic tool used to produce cores.

Core Print - A projection on the pattern that leaves an impression in the mold for supporting the core.

Core Wash - A liquid suspension of a refractory material applied to cores and dried (intended to improve surface of castings).

Coupon - An extra piece of metal, either cast separately or attached to the casting, used to determine the mechanical or physical properties of the alloy.

Crucible - A receptacle made of refractory materials used for melting and holding molten metal.

Crush - The displacement of sand at mold joints.

Cure - To harden

Deburring - The removal of fins or sharp edges from casting.

Draft - Taper on the vertical sides of a pattern or core box that permits the core or sand mold to be removed without distortion or tearing of the sand.

Drag - The bottom half of a horizontally parted mold.

Dye Penetrant Inspection - An inspection method used to detect or other surface defects in non-magnetic materials by injecting colored liquid.

Elasticity - The property of recovering original shape and dimensions when deforming force is removed.

Elongation - The amount of permanent extension near the fractures in a tensile test, expressed as a percentage of original gauge length.

External Chill - A piece of heat-conducting material (usually metal) placed in the mold wall that induces rapid cooling of the molten metal in the mold.

Facing Sand - The sand used to surround the pattern that produces the surface in contact with the molten metal.

Fatigue - Tendency of a material to break under repeated cyclic stress.

Feeder - Part of the sating system that forms the reservoir of molten metal necessary to compensate for losses due to shrinkage as the metal solidifies; riser

Fillet - A concave piece of material used to replace sharp corners on patterns or core boxes; may be part of the mold (struck) or made separately (planted).

Fin - A thin projection of metal on a casting resulting from imperfect mold or core joints.

Finish Allowance - The amount of stock left on the surface of a casting for machining.

Finish Mark - A symbol appearing on the line of a drawing that represents the edge of the surface to be machined or otherwise finished.

Flash - A thin section of metal formed at the mold, core, or die joint or parting in a casting.

Flask - A rigid metal or wood frame used to hold the sand of which a mold is formed and usually consists of two parts, cope and drag.

Floor Molding - Used when pattern sizes prohibit the use of a molding machine; the pattern is bolted to the floor, and the assembled mold is moved by crane.

Fluxing - Applying a solid or gaseous material to molten metal in order to remove oxides and other foreign material.

Foundry Returns - Metal (of known composition) in the form of gates, sprues, runners, risers and scrapped castings returned to the furnace for remelting.

Gage - A device for determining the dimensional size of an object (also spelled gauge).

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 - The portion of the runner where molten metal enters the mold cavity.

Grain - An individual crystal in a metal or alloy. Also an individual component of aggregate when referring to metalcasting sands.

Green Sand - Moist, clay bonded molding sand.

Heat - A single furnace charge of 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 mechanical properties.

Holding Furnace - A furnace for maintaining molten metal supplied from a larger melting furnace at the proper pouring temperature.

Hot Tear - Irregularly shaped fracture in a casting resulting from stresses set up by steep thermal gradients within the casting during solidification.

Impregnation - Treatment of castings with a sealing material to stop pressure leaks.

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

Ingot - A mass of metal cast to a convenient size and shape for remelting or hot working.

Inserts - Parts formed from a secondary material and placed in the mold to function as integral structural parts of the casting.

Jobbing Foundry - A metalcasting facility that manufactures castings not intended for use in its own product.

Ladle - A container used to transfer molten metal from the furnace to the mold.

Locating Pad - A projection on a casting that helps maintain alignment of the casting for machining operations.

Locating Surface - A casting surface to be used as a basis for measurement in making secondary machining operations.

Lost Foam - A casting process in which a foam pattern is placed in a flask filled with loose sand, and molten metal is poured onto the pattern, replacing its shape and forming a casting.

Machinability - Index or rate of removal by machining methods, usually expressed as cutting speed in surface ft./minute or depth of cut.

Master Pattern - The object from which a die can be made; generally a metal or wooden model of the part to be cast with process shrinkage added.

Matchplate - A metal plate to which pattern is attached at parting line.

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".

Melting Range - Pure metals melt at on definite temperature, but constituents of alloys melt at different temperatures; the variation from the lowest to the highest is called the melting range.

Metal Lot - A master heat that has been approved for casting and given a sequential number by the metal caster.

Misrun - Denotes an irregularity of the casting surface caused by incomplete filling of the mold so that the casting is not fully formed.

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 a definite shape.

Mold Cavity - The impression in the mold produced by removal of the pattern. It is filled with molten metal to produce the casting.

Mold Coating (See core wash)

No Bake Process- Molds or cores produced with resin bonded, air setting sand. Also known as the airset process because molds are left to harden under atmospheric conditions.

Orientation - The position of a part or tool in a production operation.

Oxidation - a) A reaction of an element with oxygen. b) Any process which increases the proportion of oxygen or acid-forming element or radical in a compound.

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.

Pattern Draft (See draft)

Pattern Layout - Full-sized drawing of a pattern showing its arrangement and structural features.

Patternmaker's Shrinkage - The shrinkage allowance made on all patterns to compensate for the change in dimensions as the solidified casting cools in the mold from freezing temperature of the metal to room temperature. The pattern is made larger by the amount of shrinkage characteristic of the particular metal in the casting and the amount of resulting contraction to be encountered.

Permeability - The property of a mold material to allow passage of mold or core gases during pouring of molten metal.

Physical Properties - Properties of matter such as density, electrical and thermal conductivity, expansion and spedfic heat. This term should not be used interchangeably with "mechanical properties".

Pilot or Sample Casting - A casting made from a pattern produced in a production die or mold to check the accuracy of dimensions and quality of castings that will be made.

Pinhole Porosity - Very small scattered throughout a casting, possibly caused by microshrinkage or gas evolution during solidification.

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.

Pouring Basin - The enlarged mouth of the sprue into which molten metal is poured.

Quenching - Rapid cooling from an elevated temperature for hardening, normally achieved by immersion of the object in water, oil, or salt or organic compound solutions.

Refractory - Heat resistant ceramic material.

Reject Rate - Ratio of number of parts scrapped to the total number of parts manufactured, expressed as a percentage.

Riser (See feeder)

Runner System or Gating - The set of channels in a mold through 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).

Sand Inclusions - Cavities or surface imperfections on a casting caused be sand washing into the mold.

Scrap - a) Any scrap metal melted (usually with suitable additions of ingot) to produce castings. b) Reject castings.

Shakeout - The process of separating the solidified casting from the mold material.

Short Run - Insufficient metal in the ladle to fill the mold.

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.

Slag Inclusions - Casting surface imperfections similar to sand inclusions but containing impurities from the charge from the charge materials, silica and clay eroded from the refractory lining, and ash from the fuel during the melting process. May also originate from metal-refractory reactions occurring in the ladle during pouring of the casting.

Slurry - A flowable mixture of refractory particles suspended in a liquid.

Stress Relieving - A process of reducing residual stresses in a casting by heating it to a suitable temperature and holding it for a sufficient time.

Surface Treating - Any method of treating the surface of a metal to make it more resistant to weather or chemical attack.

Test Bar - Standard specimen bar designed to permit determination of mechanical properties of the metal from which it was poured.

Thermal Expansion - The increase in the linear dimension and volume of a material accompanying a change of temperature.

Tilt Pouring - In permanent molding, when the mold is moved from a low angle to a vertical position during pouring.

Vent - An opening or passage in a mold or core to facilitate escape of gases when the mold is poured.

Warpage - Deformation other than contraction that develops in a casting between solidification and room temperature. Distortion occurring during annealing, stress relieving and high temperature service.

Yield or Casting Yield - The percentage of quality degated castings produced in relation to the amount of molten metal poured.