(1. 北京科技大学 新材料技术研究院，北京 100083；
2. 内蒙古工业大学 材料科学与工程学院，呼和浩特 010051)
摘 要: 基于Deform-3D有限元分析平台，采用所开发的焊合过程网格重构技术，分析方形管分流模双孔挤压时焊合室深度及焊合角对成形质量的影响。结果表明：焊合面平均静水压力、分流桥底部等效应力及模芯最大偏移量随焊合室深度的增加而增加；综合考虑焊合质量、模具应力集中及型材尺寸精度等因素，分流模合适的焊合室深度为10~16mm；随着焊合角的增加，焊合室内死区体积及挤压力均增大，而模芯最大变形偏移量呈减小趋势；综合考虑焊合角对挤压过程死区大小、模芯的稳定性及挤压力大小的影响，分流模合适的焊合角为30˚~45˚。实验结果和模拟结果在金属流动景象、死区位置、死区形状等方面吻合较好。
关键字: 有限元模拟；分流模挤压；焊合室深度；焊合角
quality of extrusion of square tube by porthole die
（1. Advanced Materials and Technologies Institute, University of Science and Technology Beijing, Beijing 100083, China;
(2. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhat 010051, China）
Abstract:Adopting commercial FEM soft Deform-3D and welding mesh reconstruction method, the influences of welding chamber depth and welding angle on forming quality of diplopore extrusion of square tube by a porthole die were analyzed. The results show that, the hydrostatic stress of welding plane, equivalent stress on the bottom of flow-separating bridge and maximal offset of die mandrel increase with increasing the welding chamber depth. Comprehensively considering the factors of welding quality, stress concentration of die and size-precision of the profile, the reasonable welding chamber depth of the porthole die is from 10mm to 16mm. With the welding angle increasing, the dead zone volume in welding chamber and the extrusion force increase, but the maximal offset of the die mandrel decreases. Comprehensively considering the influences of welding angle on the dead zone during extrusion, the stability of die mandrel and the extrusion force, the reasonable welding angle of the porthole die is from 30° to 45°. The experimental and simulation results agree well in the metal flow, position and shape of dead zone.
Key words: finite element simulation; porthole-die extrusion; welding chamber depth; welding angle
