The Vacuum Ingot Casting process is applied to produce forging ingots of 100-800 metric tons. Steels for the production of such ingots should contain very low hydrogen level, typically below 1ppm.
- Sequence casting of several smaller heats into one very large ingot.
- Vacuum degassing of steel takes place during casting (exposing of the poured stream of steel into the vacuum of less than 2 mbar).
- Optionally, liquid steel can be partly degassed in a standard tank type degasser prior to vacuum ingot casting.
- The ingot mold is placed on the bottom of the vacuum tank
- A pony ladle, placed on the vacuum tank cover above the vacuum-tight discharge connection to the vacuum tank acts as a tundish, reducing ferrostatic pressure of the steel flowing into the ingot mold and allowing several ladles to be cast into the same ingot mold.
- Steam Ejector or Mechanical Vacuum Pumps can be used for the generation of the necessary vacuum level during casting.