| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a refining method of a highly cleaned dead-soft steel whose cleanliness can drastically be improved. SOLUTION: In the method of adding a slag reforming agent containing metallic Al or Al alloy at the time of tapping non-deoxidized or slightly deoxidized molten steel and adding metallic Al or Al alloy to execute the deoxidation, and also adding flux(FL) after completing decarburization in a vacuum degassing apparatus, the following conditions (1)-(3) are satisfied. (1) a ratio of (wt% CaO)/(wt% Al2 O3 ) in the slag after adding the reforming agent is 1-2. (2) FL consists mainly of CaO and its grain diameter is 0.1-10mm. (3) FL adding quantity Y (kg/t) is in the range of the following formula 1). (0.1.X+1)<=Y<= (0.4∞VX+4)...1) Wherein, X is slag quantity (kg/t) at the time of reaching the degassing apparatus.</p> |
