| 摘要 |
PROBLEM TO BE SOLVED: To secure the excellent accuracy of dimensions and shapes and surface roughness even when an inexpensive welded tube is used and efficient parallel swaging is utilized. SOLUTION: After a mandrel 23 is inserted into a tube stock 20 composed of an electric welded tube, the parallel swaging is performed by moving a cylindrical die 24 and the end part of the tube stock 20 is brought into close contact with the parallel forming part 27 of the mandrel 23. After completing the parallel swaging, the die 24 is drawn out of the tube stock 20, and a pressing die 33 is made to approach the tube stock 20 from the outside in the radial direction with the mandrel 23 left in the tube stock 20 and crushes the weld bead part of the tube stock 20 in cooperation with the mandrel 23. COPYRIGHT: (C)2003,JPO
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