Vacuum Induction Melting is the melting of metal via electromagnetic induction under vacuum. An induction furnace containing a refractory lined crucible surrounded by an induction coil is located inside a vacuum chamber. The induction furnace is connected to an AC power source at a frequency precisely matched to the furnace size and material being melted.

Material is charged into the induction furnace under vacuum and power is applied to melt the charge. Additional charges are made to bring the liquid metal volume to the desired melt capacity.

The molten metal is refined under vacuum and the chemistry adjusted until the precise melt chemistry is achieved. Impurities are removed by chemical reaction, dissociation, flotation and volatilization. When the desired melt chemistry is achieved, a preheated tundish is inserted through a valve isolated hot tundish insertion lock. This refractory tundish is positioned in front of the induction furnace and the molten metal is poured through the tundish, into the awaiting molds.

VIM is a process used to make superalloys, stainless steels, magnetic and battery alloys, electronic alloys, and other demanding high valve alloys.