| 摘要 |
PURPOSE:To improve the yield of the blooming work, by giving a strong rolling reduction at the specified draft percentage for the bottom rolling and the top rolling in the latter half of the rolling pass schedule for the killed steel, so a to shift the zone of dense segregation at the central portion of the steel ingot to the top side. CONSTITUTION:At the latter half of the rolling pass schedule for the killed steel, a strong rolling reduction is given taking the ratio of draft percentage between the bottom rolling and the top rolling as above two, so as to improve the degree of penetration of the rolling reduction into the central zone of the steel ingot. According to this method (the draft percentage for the bottom rolling is 15-20%/pass) 12, as compared with the conventional method (the draft percentage is 10-15%/pass) 11, the position of the center of shoulder part of the riser of the steel ingot is 7-12 index shifted to the top side of the steel ingot depending on the strong rolling reduction, therefore, the cut-off percentage for the top of steel ingot can be reduced. |
