| 摘要 |
PROBLEM TO BE SOLVED: To suppress spitting by suppressing surely coalescence of jet flows, while achieving soft blowing by increasing pores, when performing a refining treatment by blasting refining gas onto the bath surface of molten metal from a top-blown lance.SOLUTION: A top-blown lance 2 is inserted into an upper part of a refining vessel 4 toward molten metal 3 stored in the refining vessel 4. The top-blown lance 2 has a center injection hole 21 on a tip face 8. The top-blown lance 2 in which a plurality of peripheral injection holes 22 are arranged on the circumference of a concentric circle on the tip face 8 around the center axis of the center injection hole 21, and the center axis of the peripheral injection holes 22 is tilted with respect to the center axis of the center injection hole 21, is installed so as to satisfy formula (1): &egr;=h/H>0.025; where h is the shortest distance between the circumference of the center injection hole 21 and the circumference of the plurality of peripheral injection holes 22, and H is a lance height. |
