Abstract:
Taking the typical feature structure, namely U-shaped beam, of automotive hot-stamped parts as the object, the high-temperature fracture phenomena of BR1500HS steel sheet during hot forming was predicted by the combination of high-temperature fracture criterion and numerical simulation. The effects of female die fillet radius
R on the steel sheet fracture behavior were analyzed. The results show that the fracture locations predicted by the hot forming fracture prediction model of high strength steel agreed well with the experimental results, and the relative error was below 10% between the predicted and experimental punch temperatures, indicating the relatively high reliability of the model. With
R increasing, the fracture initiation time of the plank increased. The fracture initiation located at the side wall of one end of the U-shaped beam, but these locations along the height direction were different. The plank fractured along the longitudinal direction of the U-shaped beam, and the secondary fracture occurred at the side wall of another end of the U-shaped beam when
R was equal to 2 mm and 6.5 mm. The fracture tended to appear at the side wall of U-shaped beam near the mould corner with a relatively small corner radius.