| 摘要 |
PROBLEM TO BE SOLVED: To provide a method, with which the refining control at the initial stage of the refining is suitably executed and dephosphorizing efficiency is improved to the max. and the efficient blow refining in a converter can be obtd. in small unit requirement of refining agent by continuously measuring molten steel temp. in the converter blow-refining. SOLUTION: In the top-bottom combined blow converter operation, while continuously measuring the molten iron temp. T, one or more indexes among F, L/L0 andεbased on the equation: T=[3.7×F-11.4×(L/L0 )-4.4×ε+80-α]/0.05 is controlled for 3-6 min after start of refining to control the molten iron temp. T so that a parameterαbecomes 5-15. Wherein, T is the molten iron temp. ( deg.C), F is oxygen feeding speed (Nm<3> /min/t), L is a cavity depth with the top- blown gas (mm), L0 is bath depth (mm) andεis a stirring energy density with the bottom-blown gas (KW/t).
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