Glossary of Casting Terms (A-C)

Aerate – To fluff up molding sand to reduce its density.

Air Set – Chemically bonded core sand typically used for low volume production.

Alloy – A substance having metallic properties and composed of two or more chemical elements of which at least one is a metal.

“As Cast” Condition – Casting without subsequent heat treatment.

Back Draft – Reverse taper which would prevent removal of a pattern from a mold or a core from a corebox.

Binder – A material, other than water, added to sand to bind particles together, sometimes with the aid of heat.

Bleeder – A defect wherin a casting lacks completeness due to molten metal draining or leaking out of some part of the mold cavity after pouring has stopped.

Blind Riser – A riser that is not open to the exterior of the mold.

Blow – A term describing the trapping of gas in castings, causin voids in the metal.

Boss – A relatively heavy, but short, projection on a casting.

BTU – British Thermal Unit – Quantity of heat required to raise the temperature of one lbs. of water 1 degree Farenheit at or near its point of maximum density.

Burn Out – Firing a mold at a high temperature to remove pattern material residue.

Burnt-On Sand – A misnomer usually due to metal penetration in sand mold resulting in a rough surface of the casting.

Casting Yield – The weight of casting or castings divided by the total weight of metal poured into the mold, expressed as a percent.

Chaplets – Metal supports or spacers used in molds to maintain cores, or parts of the mold which are not self-supporting in the proper positions during casting. They become a permanent part of the casting.

Charge – A given weight of metal introduced into the furnace.

Chills – Metal inserts in molds or cores at the surface of a casing or within the mold which serve to hasten solidification.

Cold Shot – Small globule of metal embedded in, but not entirely fused with the casting.

Cold Shut – A casting defect caused by imperfect fusing of molten metal coming together from opposite directions in a mold, or due to folding of the surface.

Continuous Casting – A process for forming a bar of constant cross-section, directly from molten metal by gradually withdrawing the bar from a die as the metal flowing into the die solidifies.

Cope – Upper or topmost section of a flask, mold, or pattern.

Cope and Drag Patterns – Pattern equipment in which the cope and drag pattern sections are mounted on separate pattern boards so that the cope and drag mold sections can be made at the same time.

Core – A preformed sand aggregate inserted into a mold to shape the interior of the casting or that part of a casting which cannot be shaped by the pattern.

Core Blow – A gas pocket in a casting adjacent to a cored cavity and caused by entrapped gases from the core.

Core Cavity – The cavity produced in a casting by use of a core.

Core Oil – A binder for core sand that sets when baked and is destroyed by the heat from the cooling casting.

Core Plates – Heat resistant plates used to support cores while being baked; may be metal or non-metallic, the latter being a requisite with dielectric core baking.