METHOD FOR MANUFACTURING FERRITIC STAINLESS STEEL SLABS WITH EQUIAXED GRAIN STRUCTURES AND THE FERRITIC STAINLESS STEEL MANUFACTURED BY IT

摘要

Disclosed is a method for manufacturing ferritic stainless steel slabs with equiaxed grain structures and the ferritic stainless steel manufactured by it, which control concentration of alumina inclusions in molten steel to maximize an available TiN generation effect serving as a non-uniform nucleating site of ferrite when solidifying it, thereby improving equiaxed crystal ratio, the method comprising the steps of: performing oxygen decarburization reaction by blowing oxygen from the upper part of the molten steel in a vacuum oxygen decarburization ladle; injecting Al in the molten steel to which the oxygen decarburization reaction is made for Cr₂O₃ reduction; making composite deoxidation by injecting deoxidizer in the molten steel into which the Al is injected for the Cr₂O₃ reduction; making alloying process by injecting alloying metal in the molten steel; first judging for judging whether Al concentration is in the range of a setting value by analyzing the Al concentration in the molten steel; if the Al concentration satisfies the setting value, stirring it using inert gas and second judging for judging whether alumina inclusion concentration in the final molten steel corresponds to a target value; and if the alumina inclusion concentration satisfies the target value, continuously casting the molten steel.