Less-loading hydroforming process for large-size hollow components of aluminum alloy

Abstract

To overcome the problem of welding distortion on conventional multiple segment structures, and the problem of requiring large-scale forming equipment and severe thinning occurs in high-pressure hydroforming process, a novel less-loading hydroforming process is proposed for manufacturing large-size hollow components in this paper. The geometrical relationship of the tube blank during less-loading hydroforming process is firstly discussed. Then, experiment and numerical simulation are conducted to investigate the forming behavior of a large-size tubular component of aluminum alloy 5A06 with rectangular cross-section. It is found that the needed internal pressure, die closing force, and axial force for the less-loading hydroforming are significantly reduced, which are about 1/22, 1/8 and 1/28 of those required in high-pressure hydroforming, respectively. During the less-loading hydroforming process, the tube blank is firstly deformed by bending to fill the die corners, and then deformed by circumferential compression. Moreover, the compression deformation characteristics make the thickness increase. However, a too large circumferential compression and/or an insufficient supporting pressure will cause a wrinkle defect. These results provide insights for less-loading and approaching uniform manufacturing of large-size hollow components.