| 摘要 |
PROBLEM TO BE SOLVED: To prevent an elution of hexavalent Cr from a removed slag in a melting and refining process of a chromium-containing steel. SOLUTION: A desulfurizing partition ratio (S)/[S] between the molten steel and the slag, is adjusted so as to satisfy the formula, log(S)/[S]>=0.08[-614/T +0.531[C]+0,413[Si]+0.616(T.CaO)/(SiO2)-0.047(Al2 O3)+0.0176(MgO)+0.0264(CaF2)+0.172] (wherein, T is the molten steel temperature ( deg.C); [C] is C concentration in the molten steel (concentration is mass %, the same shall apply hereinafter); [Si] is Si concentration in the molten steel; (T.CaO) is the conversion concentration of Ca in (CaO) and Ca in (CaF2) in the slag into CaO; (SiO2) is SiO2 concentration in the slag; (Al2O3) is Al2O3 concentration in the slag; (MgO) is MgO concentration in the slag; and (CaF2) is CaF2 concentration in the slag). Further, for promoting the desulfurization, the melting and refining time is lengthened or the deoxidizer such as Si, Al, is added.
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