| 摘要 |
PURPOSE:To improve the performance of straightening and the reliability thereof by installing an expander used for applying a correcting pressure from the inside of a pipe to its radial direction as well as applying a bending moment for straightening the warp of pipe from the outside of pipe. CONSTITUTION:An expander 10 is arranged in the inside of a pipe (a) to be worked, and plural segments 3 are disposed on the outer circumference of a cone 2. Next, a pair of supporting rolls 11a, 11b is installed below the working part of pipe (a), and a pair of holding rolls 12a, 12b are arranged above it at a proper space interval. When a pulling force P is applied to a rod 1, the segment 3 group produces a correcting pressure against the pipe (a) in its radial direction through the cone 2 to correct the out of roundness. Further, the out of roundness and straightness of pipe (a) are simultaneously straightend by imposing loads W on the rolls 12a, 12b. In this way, the straightening performance for a pipe is improved together with the reliability thereof. |
