| 摘要 |
PROBLEM TO BE SOLVED: To obtain the ingot of extremely low manganese using the electrode having a relatively high Mn content with a consumable electrode type vacuum melting method by setting the degree of vacuum of a melting furnace into the specified range using the electrode having the specified range of Mn content and re-melting with the diameter of the obtainable ingot, the degree of vacuum during melting and the specified relation of melting speed. SOLUTION: The degree of vacuum of the melting furnace is set into <10 Pa using the consumptive electrode containing 0.060-0.30 wt.% Mn. And when the diameter of the obtainable ingot is meant by D (mm) and the degree of vacuum during melting is meant by P (Pa), the vacuum arc re-melting is executed at the melting speed V (kg/min) satisfying the inequality I: 0.2<=V<= 0.0002×D/P×([Mn]-0.05)}+2.7 in the case of 0.006<=[Mn]<=0.15, and the inequality II: 0.2<=V<= 0.013×D/P+16.7}(0.3-[Mn])+0.2 in the case of 0.15<[Mn]<=0.30, respectively. By this way, the ingot of the alloy (SUS 316 L) containing <=0.05 wt.% Mn is obtained.
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