vacuum pouring

Vacuum ingot pouring is a metallurgical process used to produce very large steel ingots, often for components like power generator rotors. In this method, an ingot mold is placed within a vacuum tank. Liquid steel is poured into a smaller ladle on top of the tank. When the ferrostatic pressure is sufficient, the steel flows into the mold, passing through a vacuum. This degassing process, particularly the reduction of hydrogen content, is crucial for large ingots.1

Vacuum arc remelting (VAR) is another process used for casting steels with easily oxidized alloying elements. It involves melting a consumable electrode under vacuum using an electric arc. The molten metal solidifies in a water-cooled mold, resulting in directional solidification and improved ingot quality. VAR also reduces levels of dissolved gases and elements with high vapor pressure.2