| 摘要 |
The present invention relates to a molding method of reducing a diameter in an end portion of a metal tube to be characterized in having a step of rotating a metal tube around an axial core or rotating a frame in which a plurality of ring-shaped tools are arranged, and moving the axial core of the ring-shaped tool away from the axial core of the metal tube while moving the metal tube or the frame, thereby reducing the diameter in an end portion of the metal tube.
|
