| 摘要 |
PROBLEM TO BE SOLVED: To provide a forming method for an end of a metal pipe which does not cause any interference of a side of the pipe material with the side of a punch. SOLUTION: In a first forming stage, a straight metal pipe material is formed into a pipe material 1B having its upper end formed to a cylindrical part 13 which is to become later a right side of a large diameter section of the metal pipe. After inserting the pipe material 1B into a forming cavity 44 of a second metal die 4, a punch 52 of a second punch 5 is forcibly inserted into the upper end of the pipe material 1B. Then a left side in the large diameter section of the metal pipe, which is not formed in the first forming stage, is formed by a large diameter cavity 44d of the forming cavity 44 and a large diameter 52a of the punch 52. Consequently, the entire part of the large diameter section of the metal pipe 1 is formed.
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