Method to protect the surface of metal in vertical melting furnaces

摘要

Inert liquid gas such as liquid nitrogen or liquid argon is used in vertical melting furnaces to prevent oxidation of the metal during holding periods. The method can be applied to any kind of metal. The use of inert liquid gas for the "blow-dow" of the furnace will flush art all existing furnace atmosphere and prevent oxidation. The casting recovery time may be reduced from about one hour to 15 minutes. Also the layers of oxide resulting from oxidation can be negated, allowing for fewer rejects, if any, during further surface treatment.