FLUID PRESSURE FORMING METHOD AND FLUID PRESSURE FORMING DIE

摘要

PROBLEM TO BE SOLVED: To provide a fluid pressure forming method in which a thickness of a specific side in a polygon cross-sectioned portion can be thicker than that of an original tube material, and a mechanical strength of a formed product can be also improved by increase of the thickness and a work hardening through forming process, when forming the hollow member having a polygon cross-section by fluid pressure, and a fluid pressure forming die used for such forming.;SOLUTION: Both of dies 3 and 4 are simultaneously operated through both sides of a metal tube material T, which is kept in a die cavity 2a. A slanting faces 3b and 4b having an angle θ with a range of 135 to 165 degree against a sliding contact surface 2a between the die cavity 2a and the dies 3 and 4 are further arranged at an edge portion of forming faces 3a and 4a of the dies 3 and 4. A specific cross-sectioned profile portion of a formed polygon cross-sectioned member P1 is formed to be shorter than a circumferential length of a cross-sectioned portion of the pre-formed tube material T.;COPYRIGHT: (C)2001,JPO