通过建立6063铝合金多孔分流模挤压过程的三维有限元模型,研究不同挤压速度下挤压力、焊合面温度、焊合压力和材料有效应力等参数的演变规律及其对焊合质量的影响,建立预测铝合金方管焊合质量的评价模型,并采用膨胀实验验证模型的准确性.结果表明:随着金属流入分流孔、焊合室和定径带,挤压力逐渐增大并达到峰值,而后缓慢降低;随着挤压速度的增大,焊合面温度、焊合压力和有效应力逐渐升高,焊合质量系数k值逐渐降低.膨胀结果表明,最大载荷处的位移与k值呈正相关,说明所建立的k值模型具有较高的精度.%The evolution of extrusion pressure, temperature, welding pressure and effective stress of 6063 aluminum alloy were investigated under different extrusion pressures through building up three-dimensional FE simulation during porthole extrusion, and their effect on the quality of the weld seams were evaluated. The evaluation welding quality model was established and its accuracy was verified by expanding tests. FE simulation results reveal that the extrusion pressure increases with the metal flowing into the inlet ports, welding chamber and die bearing. Over the pressure peak, the extrusion pressure decreases continuously. As ram speed increasing, the temperatures, the mean stresses and the effective stresses on the welding plane in the welding chamber increase. k value shows downward trend with the ram speed increasing. Expanding tests confirm that the extrusion at higher ram speed leads to a bad bonding at the longitudinal weld seams, which corresponds to the k value.
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