| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for refining molten high carbon steel with which the generation of harmful inclusion causing quality problem, is restrained without using fluorite. SOLUTION: In decarburization with a refining apparatus having a top-bottom combined blowing function by using molten iron lowered to <=0.050% [P] through a dephosphorizing treatment, this refining method for molten high carbon steel is performed, by which lime powder together with the top-blown oxygen gas are injected, and in the case of using tO (min) for blowing time of the oxygen gas and t (min) for injection completing time of the lime powder from starting time of the oxygen blowing, t/tO is made to >=0.7 and the fluorite concentration in slag when the oxygen-blowing is stopped, is made to <=0.5%.
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