| 摘要 |
PURPOSE:To reduce the amount of crops, and to improve the yield, by carrying out a step-forming rolling pass before a broadside rolling pass. CONSTITUTION:A skew broadside rolling is pass applied to a steel ingot 5 with a rolling reduction on the bottom 7 side larger than that on the top 6 side. Hereby, the breadth of the bottom 7 becomes larger than that of the top 6. During this skew broadside rolling pass, an upper work roll is inclined correspondingly to the variation in the thickness of the ingot. A longitudinal rolling pass is then applied to the ingot in order to elongate it to a certain length. Although the thickness becomes uniform as a result of said longitudinal rolling pass, the breadth of the bottom is kept as larger than that of the top as it is before the longitudinal rolling pass. A step-forming rolling pass is then applied to the ingot in the longitudinal direction so as to provide the ingot with a three-staged thickness distribution. Then, a broadside rolling pass is applied to the ingot which is thereby formed into an almost rectangular plate. Finally, a longitudinal rolling pass is applied to the plate which is hereby formed into a product having a required thickness and length; thereby, a rectangular plate 8 is manufactured. |
