| 摘要 |
PURPOSE:To obtain a billet having good inner quality without needing a high rolling reduction force by rolling with the specific rolling reduction ratio after squeeze-working a cast slab strand in the specific size range of unsolidified thickness at the step before completing the solidification. CONSTITUTION:The cast slab strand 1 is drawn out from a mold 2 for continuous casting and the squeeze-work is executed with a die 5 for squeeze-work at the step before completing the solidification and in the range, which the unsolidified thickness (d) at center part of the cast slab strand 1 satisfies the inequality. In the equation, delta: the total rolling reduction quantity with squeeze- work (mm), D: solidified thickness before squeeze-working (mm). Successively, this is rolled at 1.5-1.8 rolling reduction ratio. The range, where a cavity is easily developed in the solidified process, can be surely welded under pressure with the squeeze-work and further, as a crystal at the axial center part can be made to fine, the billet having good inner quality is obtd. with a little rolling reduction ratio. |
