Glossary of Casting Terms (D-H)

Degassing – Process for removing unwanted gasses from casting materials, typically by pumping a neutral gas through molten metal. If not removed, unwanted gases can create porosity in metals, which can compromise strength and integrity.

Density – The mass of a substance per unit volume

Drag – The bottom section of a flask, mold, or pattern

Draft – The angle in which a mold or pattern is designed to allow for the withdraw of sand or aluminum without distorting or tearing.

Draw – The amount of space required to remove a mold from a pattern

Dross – Foriegn matter: Impurity in the aluminum

Elongation – Percentage material can stretch before failure

Ferrous – Containing iron.

Fillet – A strip that gives a rounded appearance where two surfaces meet.

Flashing – Excess material formed on an object during the casting process, typically resulting from gaps formed within a parting line.

Flask – Is used to hold sand around the pattern. Typically two halves top(cope) and bottom (drag).

Gate – Channel that carries molten metal between mold cavities that would be otherwise separated. Gates are formed into a mold extraneous of the desired final product and must be removed by machining once a casting has cooled.

Green Sand – Molding sand mixture that has been tempered with water

Heat Treatment – Controlled temperature applications, including heating and/or cooling, used to produce desired properties in solid-state metals.