| 摘要 |
PURPOSE:To enable economical and simple manufacture of long-sized pipe which has so far been impossible by extending press stroke adding a mandrel during the cause of ironing. CONSTITUTION:A mandrel 3A is attached to a crosshead 1 using a mandrel fixing device 2, and a bottomed blank pipe P1 is put in the mandrel 3A. Then, the mandrel 3A is moved forward, and the pipe P1 is ironed against the die 4. During the course of ironing, the crosshead 1 is released from the mandrel 3A and retreated before the length of the mandrel 3A becomes insufficient. A mandrel 3B is brought to a space formed behind the mandrel 3A, and the mandrel 3B is added to the mandrel 3A to form a unified mandrel. Then, the pipe is pushed further forward from the position where ironing was stopped and final ironing is performed. By this way, a finished pipe having the length extending the length of the mandrel 3A and mandrel 3B can be obtained. |
