锐角模具通道等径角挤压有限元分析

Finite Element Analysis on Equal Channel Angular Pressing with Acute Die Channel Angle

采用有限元模拟研究了1100Al锐角模具通道(准=60°)等径角挤压时的坯料流动、等效应变、挤压应力以及速度分布。与准=90°模具等径角挤压坯料相比,锐角模具通道等径角挤压可以在坯料内产生更大的等效应变,有助于提高挤压的效率;但挤压过程中在两通道相交外侧尖角处出现死区,由于死区的影响,坯料横截面上等效应变分布不均匀,挤出坯料下表面区域等效应变明显高于其他区域,同时,由于挤压应力明显上升,对挤压设备以及工模具提出更高的要求。因此,锐角模具通道等径角挤压比较适合于塑性较好、强度较低的材料。

The billet flow, effective strain, extrusion stress and velocity distribution of 1100Al was investigated using finite element simulation in acute die channel angle. Compared with φ=90° die channel angle, the higher effective strain was introduced into the billet through acute die channel angle. It was helpful for improving the production efficiency. But the dead zone was found in the outer sharp comer of two channels intersection, which caused non-uniform distribution of effective strain along the cross-section of the pressed billet. The magnitude of effective strain near the bottom of the pressed billet was obviously higher than other zones. At the same time, as a result of the extrusion stress increased obviously, the requirement for extrusion equipment and tools was raised. So equal channel angular pressing with acute die channel angle is relatively fit for the materials with better plasticity and lower strength.