Numerical Analysis of the Effect of Sinusoidal Pressure Path on Thinning of Tube in Hot Metal Free Bulging Process

Light-weight and high strength alloys such as Al-Mg alloys are used in order to reduce the weight of industrial components. However these materials should be formed at elevated temperatures due to their poor formability at room temperature. Hot metal gas forming is one of the high-tech forming processes that is used to solve this problem. Recent investigation on tube hydroforming showed positive effect of oscillation of pressure paths in improving the formability of tubes. In this study, the effects of a sinusoidal pressure path on tube wall thinning of an Al6063 tube in HMGF processis investigated and the results are compared with equal constant pressure by the finite element method.Moreover, the effect of stroke on thickness reduction of the tube is also investigated. The results show that the proposed sinusoidal pressure paths have an obvious improvement of thinning in hot metal gas bulging of tube and some defects such as necking and bursting are prevented by the oscillation of the inner pressure.