Glossary of Casting Terms (I-Q)

Impregnation – The Treatment of defective castings with a sealing medium to stop pressure leaks in porous areas, using soda, drying oils, plastics, and proprietary compounds.

Inclusions – Impurities trapped in the casting during solidification.

Insert – A part, usually formed from metal, which is placed in a mold and becomes an integral part of a casting.

Internal Shrinkage – A void or network of voids within a casting caused by inadequate feeding of that section during solidification.

Investment Casting – A pattern casting process in which a wax or thermoplastic is used. The pattern is invested by a refractory slurry. After drying, the pattern is melted or burned out of the cavity and molten metal is then poured into the resulting cavity.

Jacket Mold – A wooden or metal form, which is slipped over a mold made in a snap or slip flask, to support the four sides of the mold during pouring.

Jobbing Foundry – A casting facility equipped to economically produce a single casting or in small quantities from a pattern. The term is sometimes used to designate a commercial foundry.

Ladle – Metal receptacle frequently lined with refractories used for transporting and pouring molten metal.

Liquidus – A line on a binary phase diagram, or a surface on a ternary phase diagram, representing the temperatures at which freezing begins during cooling, or melting ends during heating.

Loose Piece – Core box; part of a core box which remains embedded in the core, and is removed after lifting off the core box. Pattern; laterally-projecting part of a pattern so attached that is remains in the mold until the body of the patter is drawn. Part of a permanent mold which remains on the casting, and is removed after casting is ejected from the mold.

Macrostructure – A line on a binary phase diagram, or a surface on a ternary phase diagram, representing the temperatures at which freezing begins during cooling, or melting ends during heating.

Mechanical Properties – Those properties of a material that reveal the elastic and inelastic reaction when force is applied. or that involve relationship between stress and strain. Also known as physical properties.

Metal Lot – A master heat that has been approved for casting and given a sequential number by the foundry.

Misrun – A casting not fully formed.

Mold – The form, made of sand, metal or refractory material, which contains the cavity into which molten metal is poured to produce a casting of desired shape

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.

Mold Weight – A weight that is applied to the top of a mold to keep the mold from separating.

Molding Machine – A machine for making molds

Mulling – The mixing and kneading of molding sand with moisture and clay to develop suitable properties for molding.

Parting line – Seam formed between cope and drag portions of a mold, where additional material may accumulate and show as a raised line, called flashing, on a casting. Machining can be used to minimize or remove the appearance of a parting line.

Pattern – Object made in the shape of the object to be cast. Patterns are used to form the mold cavities into which molten metal will be poured. They can be made into a single piece or split patterns comprising upper and lower sections.

Precipitation hardening – Form of heat treatment involving precipitation from a solid solution, used to improve certain mechanical properties.

Quenching – Hardening method achieved through rapid cooling, typically by immersing in water, oil or other solution.