| 摘要 |
PURPOSE:To manufacture a long-sized metallic pipe exceeding in length of a prestroke by setting a die movably within the prescribed limits and extruding a blank pipe material in twice with the aid of a long-sized mandrel by properly changing the position of the die. CONSTITUTION:A pipe material 12 is first set to cover a long-sized mandrel 11' exceeding in length a prestroke. A die 10' is set to the first position by holding a die frame 13 at the most front end position for the advancing direction of the mandrel 11', and the material 12' is extruded through the inside of the die 10' by advancing the mandrel 11' while actuating a cylinder 1 to obtain a primary manufactured pipe part l1. Successively, after the mandrel 11', the material 12, the die 10', and the die frame 13 are retreated together in one body; a spacer, selected in conformity with a secondary manufactured-pipe length l2 so that l2=L-l1 for the final manufactured-pipe length L, is fixed between a frame 8 and the frame 13 to set the second position of the die 10'; then the secondary pipe part l2 formed by performing the extruding operation again, and a finishing pipe with length L longer than the prestroke is obtained. |
