LADLE REFINING METHOD OF MOLTEN STEEL TO BE USED FOR PRODUCING NON-DIRECTIONAL ELECTRICAL SHEET HAVING LESS IRON LOSS

摘要

PURPOSE:To obtain molten steel advantageous for easy production of a non- directional electrical sheet having less iron loss by mixing and adding a Ca alloy and a desulfurizing flux with and to the molten steel which is thoroughly deoxidized by addition of a deoxidizing agent using Si and Al then subjecting the molten steel to a degassing treatment. CONSTITUTION:Si and Al are added to molten steel to deoxidize thoroughly the molten steel and to adjust its component in the stage of a vacuum degassing treatment of the molten steel. A mixed desulfurizing agent of a Ca alloy (may be metallic Ca alone) and a deoxidizing flux is added by an injection method to the molten steel after the component adjustment under the atm. pressure by using a top blowing lance for a ladle. As a result, the dissolved S in the molten steel is decreased and the sulfide and oxide of Ca formed by the reaction thereof are quickly removed, whereby the molten steel is desulfurized and deoxidized. The intended molten steel of (S)+(O)<=0.0035% is obtd. by the refining.