| 摘要 |
PURPOSE: To stabilize the quality of products and the cost effectively produce the products by executing rolling down under specific conditions in regions where unsolidified molten steel remains, thereby producing the slab free from central segregation and center porosity and minimizing the regions of non- stationary parts. CONSTITUTION: The unsolidified rolling down is executed under the rolling down conditions satisfying the following equations I, II in the end period of solidification of an unsolidification rate of at least <=40% at the time of producing the slab 11 by using a continuous casting machine: 0.025<=(1-α)<=0.25... (I) (1-α)=δ/(D-2d)... (II),α: the ratio at which the molten steel existing in the rolling down zone position prior to the rolling down remains after the rolling down,δ: rolling reduction, D: a slab thickness, d: the solidification thickness on the inlet side of the rolling down zone. The unsolidified front end 15 of the slab 11 is rolled down by alternately operating a pair of upper and lower walking bars 12-2 on the inner side and a pair of upper and lower walking bars 12-1 on the outer side to descend, advance, ascend and retreat.
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