微通道扁管挤压成形模拟及焊合质量的预测

Extrusion forming simulation of microchannel flat tube and welding quality prediction

采用刚塑性有限元软件DEFORM-3D对微通道扁管的挤压成形进行数值模拟,得到两种分流模具挤压微通道扁管时焊合面上静水应力、等效应力和金属速度的分布以及变化规律。利用Donati提出的K参数法对两种模具的焊合面焊合质量进行预测对比,得到平面模和球面模的焊合面焊合质量指标Kad值分别为154.7和196.0,表明球面模挤压得到的扁管焊合质量优于平面模。通过实验测量两种模具挤压得到扁管的爆破压力分别为18.5MPa和26.0MPa,表明球面模挤压扁管的承压能力高于平面模,并进一步验证了预测结果。

The extrusion forming of microchannel flat tube is simulated by using rigid-plastic finite element software DEFORM- 3D. The distribution and variation of hydrostatic stress, effective stress and metal velocity on welding surface are obtained during the extrusion process with two kinds of porthole dies, viz. , flat-face die and spherical-face die. According to Donati＇s K criterion, the paper predicts and contrasts the welding quality on surfaces by the two dies. The result shows the welding quality index K, of flat-face and spherical-face die are 154.7 and 196.0, respectively, indicating better welding quality of the latter than that of the former. Finally, in the experiment, the measured burst pressure of microchannel flat tubes extruded by the two dies are 18. 5 MPa and 26.0MPa, respectively. The result indicates the pressure bearing capacity of the tube extruded by spherical-face die is higher and the prediction result of welding quality is verified.