关键词: 厚板, 直角边缘凸台, 复合工艺, 挤压成形, 镦挤成形

Abstract: In the investigation，a combined process of extrusion and upsetting extrusion is proposed by analyzing the forming technologies of the parts with rectangular edge convexity． Then，the extrusion and upsetting extrusion processes of the rectangular edge convexity are respectively simulated by using the finite element analysis software Deform-3D and by means of the rigid-plastic finite element analysis method． Simulation results show that the proposed combined process can achieve the convexity with rectangular edges，and that，during the extrusion process， the larger boss height of the anti-push punch is，the smaller the convexity edge fillet will be，which is more beneficial to form the rectangular edge convexity． It is also found that smaller boss height of the anti-push punch causes the crack defects to occur more easily on the hole wall and the end face of the convexity． According to the simulation results，a set of stamping dies are designed and manufactured，so as to verify the forming process of the convexity by experiments． The results show that the experimental results accord well with the simulation ones，and that the crack defects can be effectively reduced by increasing the punch fillet radius and by adopting the lubricating oil．

Key words: thick sheet, rectangular edge convexity, combined process, extrusion, upsetting extrusion