Pre-form design for hydro-forming of aluminum alloy automotive cross members

Abstract

Due to the requirement of lightweight in the automotive industry, aluminum alloy components with irregular cross sections have been used for body-in-white parts. In order to obtain an aluminum alloy cross member with uniform thickness distribution and acceptable dimension accuracy, a hydro-forming process of a 6063-T4 aluminum alloy cross member was studied by experimental research and numerical simulation. To avoid severe thinning and bursting during hydro-forming, the design of experiments according to a central composite design method was carried out, and the significance of pre-form structural parameters was discussed on thinning. According to the optimum pre-form shape, experimental researches were then conducted on thickness distribution of typical sectional profiles and dimension accuracy. It is shown that the maximum thinning is 14 %, which is located on sectional profile B-B. The deviation of circumferential dimension accuracy along the axial direction is 0.33 %. The maximum dimensional deviation at sectional profiles A-A and B-B is 0.19 and 0.22 mm, respectively; accordingly, the dimension accuracy along the width direction is 0.4 and 0.31 %, respectively. Finally, a sound hydro-formed cross member is obtained.