| 摘要 |
PURPOSE:To make reflection of tested result on internal quality in a cast slab to operation and to reduce center segregation by measuring the cast slab thickness after the strand cast slab is completely solidified, adjusting rolling reduction rate of rolls in case the measured value excesses the permissible range and controlling strain speed in the cast slab at the end time of the solidification. CONSTITUTION:When the strand cast slab 30 is completely solidified, the solidified cast slab 30 is straightened by a straightening roll 26 and cut to the prescribed length with a cutter 37. Next, the thickness of the cut cast slab is measured at each position thereof with measuring instrument 39 and disversing degree of the center segregation is found with an arithmetic unit 40. The permissible range of the prescribed thickness, assuming that the degree of the center segregation is minor, is beforehand grapsed, and in case the measured thickness of the cast slab excesses the permissible range of the prescribed thickness, the rolling reduction rate with the light rolling reduction rolls 16 applied in the cast slab 30 at the end time of solidification, is adjusted. By this method, the strain speed for the cast slab 30 at the end time of the solidification is controlled and the flow of molten steel in the inner part of the cast slab 30 is prevented. |
