| 摘要 |
PURPOSE:To uniformize the elongation at each part, to prevent generation of the camber and the wave, and to improve the yield, by limiting the draft percentage for each part, at continuously rolling at the latter half rolling pass the U-shaped sheet pile being forward and backward rolled at the first half rolling pass. CONSTITUTION:At the first half rolling pass to roll the thick material, the forward and backward rolling is carried out with the large draft percentage difference obtained by unbalancing the draft percentages for the hook part A, the hook bottom part B, the flange part C and the web part D. Next, at the latter half rolling pass to roll the material with thickness having been thinned, the draft percentage of each pass for rolling each part A, B, C, D, is made 5% smaller than the draft percentage for the entire sectional area of the material, and the continuous rolling work is carried out. Hereby, the elongation of each part A, B, C, D, is respectively made approximately the same, and the shape of the tip of the sheet pile can be made almost straight. |
