REFINING METHOD OF MOLTEN STEEL BY LADLE REFINING FURNACE

摘要

PURPOSE:To produce a high nitrogen steel contg. nitrogen at a prescribed ratio at a stable yield and low cost in the stage of producing the high-nitrogen steel in a ladle refining furnace by blowing gaseous nitrogen by a bubbling lance into the molten steel. CONSTITUTION:Gaseous Ar is blown by the gaseous Ar bubbling lance 4 into the molten steel in the ladle refining furnace 1 to stir the molten steel by which the component adjustment by addition of an alloy iron and refining such as dephosphorization and desulfurization are executed. The gas blow from the lance 4 is changed over from Ar to N2 in the state in the non-oxidation atmo sphere to blow the gaseous N2 into the molten steel so that the N2 is incorpo rated at the prescribed ratio into the molten steel. The high-nitrogen steel is produced at a high yield of about 60% yield by using inexpensive gaseous N2.