| 摘要 |
PURPOSE:To prevent peaking of a steel pipe squaring the edge of a steel pipe and the edge of a steel plate and welding them in forming a spiral steel pipe by adjusting the height of sectional forming rolls of inner and outer face forming stands by a quantity corresponding to warping of the plate. CONSTITUTION:A spiral steel pipe 9 is manufactured by bending a steel plate 2 by inner and outer face forming stands 7, 8. Forming rolls 10-13 and several others are arranged on each stand. When the plate 2 is bent, the edges of the plate are warped outward. Accordingly, the height of forming edge rolls 12 is adjusted to coincide with the height of the edges of the pipe 9. Then, the plate 2 positioned corresponding to the inner face forming edge rolls 12 warps upward. Accordingly, warping of the part of the plate 2 corresponding to the roll 10 can be eliminated. |
