| 摘要 |
PURPOSE:To improve the outside diametral size and out of roudness of a pipe end by setting the changed outside diameter part of the pipe end owing to setting after heat treatment of a steel pipe by pressing by half split dies for setting the outside diameter larger by as much as the size for spring back and insertion of a bore punch. CONSTITUTION:The changed outside part near the end 11 of a pipe material resulting from setting of a long-sized pipe material after heat treatment of a steel pipe is pressed by half split dies 13 larger by as much as the size for spring back than the prescribed outside diametral size. A punch 16 which is also larger by as much as the size for spring back than the prescribed bore size and has 15 pointing grade and 1/200-1/1,000 draft is press-fitted into the bore. The front end is set to the prescribed outside diametral size end out of roudness by the above-mentioned device. |
