Large-expansion Hydroforming Technology Achieving Three-times Expanding☆

Abstract Tube hydroforming is useful for the integrated forming of hollow parts, the expansion degree of which is approximately 1.1 times and 1.4 times the cross-sectional length of the blank tube at maximum. We studied large-expansion technology of hydroforming in order to target a broad range of applications of hydroforming and found that by coupling the technologies of “multi-process unidirectional expansion” and “intersectional movable die technology”, it is possible to expand the circumference of a blank tube by a factor of three without intermediate heat treatment. Additionally, we integrated the axel housings, of which only the middle part is expanded, achieving about 10% weight reduction.