| 摘要 |
PURPOSE:To easily perform the bulging formation extending the bulging extension part by interposing a liquid between a piston and pipe for bulging a bulging scheduled part and bulging it by feeding ultrahigh liquid pressure to the pipe inside. CONSTITUTION:The liquid Q of an oil, etc., is interposed between the bulging scheduled part of a pipe blank 1 subjected to die closing between upper and lower dies 2, 3 and the piston 6 enabling to bulge it in T shape. An ultrahigh pressure liquid P is fed to the blank 1 from the pistons 5, 5 for compression of pipe blanks 1, 1' to compress with pressure the blank 1 in the axial direction. The bulging scheduled part is bulged so as to push down the piston 6 via the interposed liquid Q and since the interposed liquid Q exists uniformly among the outer peripheral face 1e of the blank 1 and upper and lower dies 2, 3 an uniform action is exerted on the bulging base part 1c to be deformed in R shape as well. The bulging part extension part 1d extending straightly along the hole 4 of a die at bulging time is thus subjected to bulged forming in length.
|
