中文摘要：

基于Dynaform软件平台，建立了Y型异径三通管三维弹塑性有限元模型。运用数值模拟方法，研究了AZ31镁合金Y型异径三通管热态内高压成形过程、成形缺陷、等效应变分布。探讨了初始管坯长度、左右冲头轴向进给量与成形支管高度之间的关系；研究得到了相同支管长度下成形不同Y型夹角三通管所需的左右冲头进给量。结果表明：随着初始管坯长度减小，支管高度随之增加；在左右进给量相同的情况下，左侧金属流向支管阻力更小，支管高度增加明显；随着Y型夹角的增大，右侧冲头进给增加，轴向补料比减小，总补料比增加，当夹角为90°时，左右补料相同。

英文摘要：

Based on Dynaform software environment, a 3D elastic-plastic finite element model for Y-shape reducing tee was established. With numerical simulation, the warm hydroforming process of AZ31magnesium alloy Y-shaped reducing tee, failure behavior, forming defects , the equivalent plastic strain distribution during forming were stud- ied. The effects of the initial tube length and the axial feed of punches on the protrusion height were investigated by numerical simulation. The axial feed distances of punches for Y-shapes of the different protrusion height angles were determined. The results show the shorter is the tube length, the greater is the protrusion height formed. The feed distance of left punch influenced more remarkable than right punch on the protrusion height if the same increment of feed distance is set. The axial feed ratio decreases, the axial feed of the right punch increases and the total feed ratio increases with the increasing protrusion angle. When the protrusion angle is 90°, the axial feed of the right and left punch is equal .