HYDRAULIC BULGING METHOD, HYDRAULIC BULGING APPARATUS AND HYDRAULIC BULGED ARTICLE

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic bulging method, a hydraulic bulging apparatus and a hydraulic bulged article by which productivity is improved and working man-hour is reduced. SOLUTION: This method is a hydraulic bulging method for manufacturing a hydraulic bulged article 4 having a flange 1 by applying hydraulic pressure to the interior of a tubular material P1 after the tubular material P1 which is a base stock to be formed is preformed and has a preforming stage where a preform P2 is manufactured by preliminarily squeezing the tubular material P1, a hydraulic bulging stage where the preform P2 is bulged by applying the hydraulic pressure to the inside of the preform P2 while holding the flange 1 after forming the flange 1 by partially pressing the preform P2 and a hole making stage where a hole is made in the end part 2 of the flange which is a return part formed in the end part of the flange 1. COPYRIGHT: (C)2006,JPO&NCIPI