| 摘要 |
PROBLEM TO BE SOLVED: To provide a high efficient reduce pressure refining method, by which the industrial establishment of reduced pressure method capable of surely and stably performing decarburization and degassing till an extra-low carbon concentration range within a short time can be developed in the state restraining the spattering and sticking of metals. SOLUTION: In the reduced pressure refining method for refining molten steel 14 by dipping an immersion tube 12 into the molten steel 14 in a ladle 11 and reducing the pressure in the immersion tube 12, and also, blowing an inerts gas into the molten steel 14 from the lower part of the molten steel 14 positioned just below the immersion tube 12, when using Q (NL/min) for flow rate of the inert gas, S (m2) for widening area of bubbles in the immersion tube 12 on the molten steel surface, P (torr) for vacuum degree in the immersion tube 12 and W (ton/ch) for total weight of the molten steel 14, the refining is carried out in the range satisfying the following formula 0.02<=(Q1/3.S2/3)/(W.P2/3)<=0.10.
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