| 摘要 |
PROBLEM TO BE SOLVED: To provide an electromagnetic forming method of a polygonal cross-sectional member by which, when a member having a polygonal cross section is formed by performing tube-expansion of an aluminum alloy base stock having a cylindrical peripheral wall by electromagnetic forming, radiused parts of the corners of a cross section can be formed smaller. SOLUTION: The cross section of the aluminum alloy base stock 21 is composed of a plurality of circular-arcuate regions 22 along the peripheral direction of the nearly round basic cross section 24 and a plurality of projecting and recessing regions 23 got between the circular-arcuate regions 22. In the projecting and recessing region 23, a peripheral wall is deviated from the basic cross section 24 and projected outward, and the circumference L1 of the peripheral wall of each projecting and recessing region 23 is longer than the circumference L0 when the same region is formed into a circular-arcuate shape along the peripheral direction of the basic cross section 24. Each projecting and recessing region 23 is arranged oppositely to the corner 3a of the die 3. An electromagnetic forming coil 2 is arranged inside the aluminum alloy base stock 21. COPYRIGHT: (C)2013,JPO&INPIT |
