变截面杯形件等温压扭复合成形工艺分析

Process analysis of twist-pressure isothermal composite forming for tapered cup

采用数值模拟与物理实验相结合的方法对基于高压扭转(HPT)工艺的杯形件等温压扭复合成形进行研究,分析了等效应变场、损伤场和成形载荷。结果表明,压扭复合成形工艺改善了金属流动状态,变摩擦阻力为有益摩擦力,成形载荷由传统挤压的355t降至176t,所需扭矩8540N·m,出现最大锻件损伤值的部位在直壁顶端。进行了成形实验,所得压扭件宏观金属流线清晰可见,其微观组织不同于传统挤压件的径向纤维状而是呈弥散、均匀分布,且材料抗拉强度由挤压件的405MPa提升至431MPa。

By combining finite element simulation and physics experiment,the process analysis of the twist-pressure isothermal composite forming for tapered cup is studied.The fields of equivalent strain,damage and forming load are analyzed in details.The results show that the process has turned the friction resistance into the beneficial friction,and the flow state is improved.Moreover,the forming load decreases from 355 tto 176t,the final torque is 8540N·m,and the maximum damage occurs at the top of the straight wall.Finally,the physical experiment is conducted.The results show that the macro metal flow lines are visible on the surface of cup,its microstructure is different from the traditional extrusion part’s radial fibrous,viz.,uniformly distributed,and the tensile strength increases from 405 MPa of extrusion to 431 MPa.