Glossary

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Here is a list of common industry terms and definitions. Contact us if you recommend we add anything that’s missing.

Binder The bonding agent used as an additive to mold or core sand to impart strength or plasticity in a “green” or dry state (also see green sand).

Burn-on Sand Sand adhering to the surface of the casting which is extremely difficult to remove. May be due to soft mold, poor sand compaction, insufficient mold coating (graphite) paint, or high pouring temperatures.

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 the rate of solidification throughout the casting.

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

Cold shut A surface imperfection due to unsatisfactory fusion of metal, caused by insufficient fluidity, low pouring temperature, improper choice of alloy, or inadequate runner systems.

Cope The top half of a horizontally parted mold.

Core A metal insert in a die or made of sand and placed in mold to produce a hole in a casting.

Core assembly An assembly made from a number of cores.

Corebox The wooden, metal, or plastic tool used to produce cores.

Coreprint A projection on a pattern which leaves an impression in the mold for supporting the core.

Core wash A suspension of a refractory material applied to cores and dried. (Intended to improve surface of casting.)

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 lost wax process.

Draft Taper on the vertical sides of a pattern or corebox which 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.

Ejector pins Movable pins in pattern which help remove the mold from the pattern.

Feeder Sometimes referred to as a riser. A vertical channel in the mold(part of the runner system) which forms the reservoir of molten metal necessary to compensate for losses due to shrinkage as the metal solidifies.

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

Finish mark A symbol (f, f1, f2, etc.) appearing on the line of a drawing that represents the edge of the surface of the casting to be machined or otherwise finished.

Flask A metal or wood rigid frame without top and without fixed bottom used to hold the sand to form a mold; usually consisting of two parts, cope and drag. Used in greensand and airset molding processes.

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) The portion of the runner where the molten metal enters the mold cavity. Other gates: bottom – any gating system by which metal enters the mold cavity at the bottom.

Green sand Moist clay bonded molding sand.

Heat A single furnace charge of metal to be used for pouring directly into mold cavities; a heat may be all or part of a master heat.

Heat treatment A combination of timid heating and cooling operations applied to a casting in the sold state in a manner which will produce desired properties.

Hotbox process A furnace resin-based process which uses heated metal coreboxes to produce cores.

Hot tear Irregularly shaped fracture in a casting resulting from stresses set up by steep thermal gradients within the casting during solidification and too much rigidity of the core or mold material.

Inclusions Particles of slag, refractory materials, sand or de-oxidation products trapped in the casting during solidification.

Investment casting process A pattern casting process in which a wax or thermoplastic pattern is used. The pattern is invested (surrounded)by a refractory slurry. After the mold is dry, the pattern is melted or burned out of the mold cavity, and molten metal is poured into the resulting cavity.

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

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

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

Master pattern The object from which a pattern can be made; generally a metal model of the part to be cast with process shrinkage added.

Mechanical properties Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain; for example, the modulus of elasticity, tensile strength, and fatigue limit. 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 which contains the cavity into which molten metal is poured to produce a casting of definite shape and outline.

Mold cavity The impression in a mold produced by removal of the pattern. It is filled with molten metal to form the casting. Gates and risers are not considered part of the mold cavity.

No-bake process Molds/cores produced with resin-bonded air-setting sand. Also know as the air-set 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, 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 The taper allowed on the vertical faces of a pattern to permit easy withdrawal of a mold.

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

Patternmaker’s ShrinkageThe shrinkage allowance made on all patterns to compensate for the change in dimensions as the casting solidifies in the mold. 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. Rules or scales are available for use.

Permeability The property of a mold material to allow gases to pass through its material.

Physical properties Property of matter such as density, electrical and thermal conductivity, expansion, and specific 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 to check the accuracy of dimensions and quality of castings which will be made in quantity.

Porosity (blow-holes) Holes in the casting due to gases trapped in the mold, reaction of molten metal with moisture in the molding sand, or imperfect fusion of caplets with molten metal. (Surface porosity may be due to overheating of the mold or core faces, but should not be confused with sand inclusions.)

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 (See feeder.)

Runner system or gating 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 leading from the mold cavity further vertical channels (risers or feeders).

Sand inclusions Cavities or surface imperfections on a casting caused by sand washing into the mold cavity.

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 is also used to describe the casting defect, i.e., shrinkage cavity. This results from poor design, insufficient metal feed, or inadequate feeding.

Slag A fused nonmetallic material used to protect molten metal from the air and to extract certain impurities.

Slag inclusions Casting surface imperfections similar to sand inclusions, but containing impurities from the charge materials, silica and clay eroded from the refractory reactions occurring in the ladle during pouring of the casting.

Sodium silicate Molding sand is mixed with sodium silicate and the mold is gassed with carbon

CO: process dioxide gas to produce a hard mold or core.

Sprue (downsprue) The channel, usually vertical, through which the molten metal enters the mold cavity.

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

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

 

Resource Information: Casting Buyer’s Guide – The American Foundry Society