PURPOSE: To obtain a working method for easily and effectively controlling the wall thickness of an inner bead to an arbitrary desired thickness by abutting a bead forming tool on the circumferential wall of a metallic pipe while a compressive force is imparted to the pipe in the axial direction.
CONSTITUTION: A mandrel 4, 5 is inserted into both sides of a pipe 1 with a prescribed space 6 apart between the tip ends of the mandrels 4, 5. Then, while the pipe 1 is rotated with a compressive force imparted to the pipe 1 in the axial direction, a roll 7 as a bead forming tool is abutted on the outer circumference of the pipe 1. Thus, the circumferential wall of the pipe 1 is deformed continuously without interruption to the inward side of the space 6 between the tip ends of the mandrels 4, 5. The compressive force is continuously imparted to the pipe 1 in the axial direction, from the start to the end of the working of the inner bead 2 by the roll 7 on the circumferential wall of the pipe 1. The ratio of thinning the wall thickness of the bead 2 is improved more with a larger compressive force.
IWATATE KOJI
NAKAHARA YOSHIHIRO
MAEHARA HISASHI
TAKAMI YUICHI
SHOWA ALUMINUM CORP
| JPS51100960A | 1976-09-06 | |||
| JPS5356161A | 1978-05-22 | |||
| JPS6313625A | 1988-01-20 | |||
| JPS6027418A | 1985-02-12 |
Next Patent: METHOD AND DEVICE FOR TREATING HOLE PART EDGE OF PRESS PRODUCT