V

Vacuum Casting:  A casting process in which metal is melted and poured under very low atmospheric pressure; a form of permanent mold
casting where the mold is inserted into liquid metal, vacuum is applied and metal drawn up into the cavity.

Vacuum Degassing:  The use of vacuum technique to remove dissolved gases from molten alloys.

Vacuum Refining:  Melting in a vacuum, usually by electrical induction, to remove gaseous contaminants from the metal.

Vanadium:  A white, hard, metallic element, mp 1800 C (3272 F), used as an alloy in iron and steel; a powerful carbide stabilizer and deoxidizer.

Vegetable Oils:  Oils extracted from plants, used as drying oils in core oil manufacture. Linseed oil is an example.

Veining:  A defect on the surface of a casting appearing as fins, veins or wrinkles and associated with excessive thermal movement of the sand, especially core sands.

Venting:  Perforation with a vent wire of the sand over and around a mold cavity to assist in the escape of the gases.

Vibrator:  A device, operated by compressed air or electricity, for loosening and withdrawing patterns from a mold, or for vibrating a hopper or chuteto promote the flow of material from the hopper or chute.

Vickers Diamond Pyramid Hardness Tester:  Patented indentation hardness machine.

Virgin Metal (Primary Metal):  Metal extracted directly from the ore; not previously used.

Viscosity:  The resistance of fluid substance to flowing, quantitatively characteristic for an individual substance at a given temperature and under other definite external conditions.

Void:  A shrinkage cavity produced in castings during solidification.