PROCESS FOR VACUUM REFINING OF MOLTEN STEEL

摘要

A process for the vacuum refining of molten steels by flowing an oxygen gas into a molten steel containing at most 0.1 wt.% of carbon in an atmosphere of a vacuumness of 105 to 195 Torr at such an oxygen feed rate as to realize a cavity depth of 150 to 400 mm in a straight-drum vacuum refining apparatus constituted of a bottom-less straight-drum vacuum tank and a ladle to effect decarburization, in which process, if necessary, the treatment of decarburization is combined with the treatment of heating aluminum fed to the vacuum tank by burning the same with an oxygen gas blown into the tank at such a feed rate as to realize a cavity depth of 50 to 400 mm, the treatment of high-vacuum degassing, the treatment of desulfurization by blowing a desulfurizing agent into the vacuum tank, or the treatment of heating with a burner by blowing a combustion aid together with oxygen into the tank, each treatment being conducted within the range of vacuumness of 100 to 400 Torr except for the high-vacuum degassing.