| 摘要 |
PROBLEM TO BE SOLVED: To provide a lance for reduced pressure smelting, which gives high smelting efficiency and is hardly affected by a degree of vacuum. SOLUTION: This lance has a nozzle 2 at the lance nose, which comprises a throat 3 with an inside diameter d, and an enlarged portion 5 with an inside diameter D and length L in the nozzle tip side of the throat, and a flute 4 with depth h, which has concave on an opposite side to the nozzle tip against the throat nose, in a border step between the throat and the enlarged portion. The values of d, D, h, and L, preferably satisfy a condition expressed by the formula (1)-(3): 0.1D<=d<=0.4D...(1), 0.1(D-d)<=h<=1.0(D-d)...(2), and 1.0d<=L<=5.0d...(3).
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