Pre-drawing and air-bulging technology of superplastic forming for automobile models

The forming of automobile models with big and complex surfaces is difficult in the practical work. The phenomena of cracking, time-consuming and non-uniform distribution of sheet thickness occurs in the forming process by using the traditional superplastic air-bulging technology. Based on the truth of metallic materials having higher tensile-strength at the superplastic lower-temperature, this paper presents a technology combined with pre-drawing at the superplastic lower-temperature and air-bulging at the optimal superplastic temperature. Finite element method is employed to simulate the forming process of an automobile-model by using both the combined technology and the traditional superplastic air-bulging technology. Finally, this paper compares the results of simulations and experiments, and draws the conclusion that, the combined technology is superior to the traditional superplastic air-bulging technology for the automobile-model’s shaping.