| 摘要 |
PROBLEM TO BE SOLVED: To provide a continuously cast slab having a little amount of large sized non-metallic inclusion while continuing a long sequential continuous casting by changing the dipping depth position of an immersion nozzle from a tundish to restrain the erosion of this immersion nozzle, and by limiting a range for changing the dipping depth position of the immersion nozzle to restrain the enclosure of the large sized non-metallic inclusion. SOLUTION: When the steel slab is produced with a continuous casting using the immersion nozzle 3 having four spouting holes 4, this operation is performed in a condition setting a stirring-flowing velocity of molten steel in a mold 2 developed from the spouting holes 4 of the molten steel in the immersion nozzle 3, in the range satisfying 0.06<=the stirring-flowing velocity V<=0.16 m/sec shown in Figure 2. Further, the depth from a meniscus of the immersion nozzle 3 to the center position of the spouting hole, i.e., the position of the dipping depth h is limited within the fixed range.
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