| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently and simultaneously executing desulfurizing and dehydrogenating reactions of molten steel. SOLUTION: At the time of simultaneously executing the desulfurizing and the dehydrogenating treatments of the molten steel charged into a ladle by applying a lime-base refining agent powder blowing method, an immersion tube is dipped into the molten steel from the upper part of the ladle and set at a blowing powder rising position. Partial pressure of oxygen in the atmosphere in the immersion tube is reduced to <=0.01(atm) and the diameter (d) of the immersion tube is controlled to satisfy the following relation with respect to the powder blowing depth H. Further, one or more, notched parts are arranged at the upper end of the outer periphery of the ladle to continuously discharge the produced slag out of the ladle. d>=D=2×xtan(12 deg.)×xH+Ld, wherein, H is the powder blowing depth and Ld is the diameter of the blowing lance.
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