(1. 山东理工大学 机械工程学院，淄博 255049；
2. 山东理工大学 计算机科学与技术学院，淄博 255049)
摘 要: 提出一种方管自弯曲挤压新工艺，通过设计倾斜分流桥结构，使金属在型腔内产生不均匀流动，从而直接挤出弯曲方管型材。利用外部网格重构方法，实现金属在型腔内分流焊合过程的模拟分析，得到自弯曲挤压过程金属流动规律、等效应力应变场分布；研究分流桥倾斜角和挤压速度对方管型材自弯曲成形性的影响，并通过挤压实验制备出自弯曲方管。结果表明：自弯曲模具结构可挤出形状规则、曲率一致的弯曲方管件，型材应力应变分布均匀，随分流桥倾斜角或挤压速度的增加，型材曲率半径呈非线性递减，挤压后弯曲方管的上表面、侧面和下表面的晶粒均匀且为等轴晶，晶粒尺寸分别为64.3、61.7和58.3 μm。
关键字: 分流焊合模拟；自弯曲挤压成形；倾斜分流桥；型材微观组织
（1. School of Mechanical Engineering, Shandong University of Technology, Zibo 255049, China;
2. School of Computer Science and Technology, Shandong University of Technology, Zibo 255049, China）
Abstract:This paper concerned a novel method for curved square tube profiles self-bending extrusion forming. By designing the inclined shunt bridge structure, the metal can generate internal differential flow, thereby directly extruding the curved square tube profile. Using external mesh reconstruction methods, the numerical simulation of shunt welding extrusion process was realized. The metal flow behavior, stress and strain field distribution in the self-bending extrusion process were obtained. The effects of inclination angle and extrusion ram velocity on the self-bending forming of square tube profiles were studied. The bent square tube profiles were obtained from the extrusion experiment. The results show that the regular and stable bending square tube can be extruded by the self-bending die structure. The distribution of stress and strain is uniform. With the increase of the inclination angle or extrusion ram velocity, the curvature radius of the profile is nonlinearly decreasing. After extrusion, the grains on the upper surface, side surface and lower surface of the curved square tube are uniform and equiaxed, and the grain sizes are 64.3, 61.7 and 58.3 μm, respectively.
Key words: shunt welding simulation; self-bending extrusion; inclined shunt bridge; profile microstructure
