PURPOSE: To add metals for component adjustment at a low cost to a molten steel without using costly alloy iron by providing hollow holes to electrodes for heating of a ladle refining furnace and blowing ore powder of the metals for component adjustment by a carrier gas through the hollow holes at the same instant as the electrical heating by the electrodes.
CONSTITUTION: The molten steel 3 is put into the ladle refining furnace 1 provided with the electrodes 5 for heating and the carbon electrodes 5 having hollow holes 8 are immersed into the molten slag in the upper part of the molten steel. An inert gas such as Ar is supplied through a pipe 2 into the ladle to maintain an inert gaseous atmosphere in the ladle. Electricity is conducted to the electrodes 5 to heat the molten steel 3. The powder of ore contg. the oxide of metals such as Nb, V and Cr is blown as the metals for the component adjustment of the molten steel through the hollow holes 8 of the electrodes 5 by the inert gas such as Ar as the carrier gas. The Nb2O5, V2O5, Cr2O3, etc., in the ore are reduced to Nb, V and Cr by the carbon of the electrodes and can be uniformly dispersed and incorporated into the molten steel under stirring of the molten steel by the gaseous Ar from lances 6, 7.
KOMATSU YOSHIMI
IKEDA MASABUMI
KONDO TSUNEO
