| 摘要 |
PURPOSE:To improve the bisymmetricity of a product and its rolling efficiency together by rolling a stock by inverting its front and rear ends in the initial several passes of break down rolling. CONSTITUTION:The 1st pass rolling of a rolling stock 7 is performed between upper and lower rolls 3, 4 provided respectively with caliber grooves 5, 6. Since slight deviation exists between the set positions of upper and lower rolls 3, 4 in the thrust direction, the deviation (e) between the upper and lower cords of a rolling stock is produced. The deviation (e) tends to increase, because the thrusts act on the rolls during several passes of ordinary sequential rolling. Therefore, the stock 7 is rolled by turning it by 180 deg. at every pass through a turn table, etc. during several of the 2nd and subsequent passes. In this way, since said deviation is reduced each pass, a product excellent in bisymmetricity is obtained from the starting of rolling and its rolling efficiency is improved.
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