Patent ID: 6112567
Filing Date: 2000-09-05
Classification: B21D

Abstract:
Method for shaping a hollow body from a tubular blank placed in a shaping tool that can be opened and closed, by internal high pressure introduced into the interior of the blank, with the blank, prior to internal high-pressure shaping, being modified in the shape of a cross section in accordance with the workpiece from a standardized delivered cross-sectional shape,wherein, for pre-shaping of the blank, a dent whose depth varies over its length is formed in the blank, said dent being configured so that a U-shaped fold that projects into the interior of the hollow body is formed with the walls of said fold abutting one another directly and merging at the periphery with a circumferential wall of the hollow body to thereby facilitate the internal high-pressure shaping of the pre-shaped blank to form a hollow body with a circumference that varies sharply over its length.