| 摘要 |
PURPOSE:To prevent the generation of wrinkles and to perform a highly efficient work by constraining the working circumference in a pipe to be worked by fixing and moving mandrels at the initial stage of drawing work, and providing positively a tension to the working part. CONSTITUTION:In drawing a pipe 11 to be worked, for instance, by a spinning method, fixing and moving mandrels 14, 15 are arranged in the vicinity of a working part in the pipe 11 at the initial stage of working, to fix the end of pipe 11. At the same time, the pipe 11 is stretched in the arrow direction by holding it by a chuck 16 to provide a tension to the pipe 11. Then the pipe 11 is drawn in a state of limiting its deformation zone, by pressing a roll 17 against the pipe 11 at the boundary between the mandrels 14, 15 while rotating the pipe 11 around its axis and constraining a deformed part deformed by the drawing part by the mandrels 14, 15. Next, the drawing of the long-sized pipe 11 is continued while moving the mandrel 15, together with the pipe 11, by the chuck 16. |
