| 摘要 |
PROBLEM TO BE SOLVED: To provide a lance for blowing with which the sticking of skull is prevented by improving cooling efficiency of the lance during top-blown refining and the stuck skull is naturally and easily dropped down with the dead weight. SOLUTION: (1) The preventive method of the sticking of the skull on the lance for converter blowing, is performed by using the lance for blowing, composed of a water-cooling type triple-tube structure and having <=0.025 m difference between the outer diameter D1 and the inner diameter d1 of the outer tube, and regulating the temperature of the cooling water flowing in the inner part of the lance to <=60 deg.C and the flowing velocity V of the cooling water to >=4.0 m/sec. (2) In the above (1) preventive method, the roughness on the outer tube surface is desirably <=10μm average roughness Ra. Further, at the portion where the sticking of the skull on the surface of the lance for blowing, is concentrated, it is desirable that one or more portions of the tapered parts downward are arranged.
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