镁合金真空电子束焊接匙孔热效应数值模拟

Numerical simulation on keyhole thermal effect of vacuum electron beam welding of magnesium alloy

分析了镁合金真空电子束焊接过程中的匙孔热效应特征,针对真空电子束焊接工艺建立了适用于镁合金焊接的复合热源模型.考虑到焊接过程中存在的高温金属蒸气等离子体及真空电子束焊接"匙孔"深熔效应特征,模型由高斯面热源和圆锥体热源复合而成,利用高斯面热源功率分配系数和圆锥体热源功率分配系数的不同取值,模拟电子束焊接的不同聚焦状态,并得到电子束聚焦状态与散焦状态下的焊接温度场变化,进而通过计算得到聚焦状态变化下的匙孔形状和焊缝成形.结果表明,模拟结果与其具有较好的一致性.

The keyhole thermal effect of vacuum electron beam welding for magnesium alloy was analyzed.In view of the thermal effect of high-temperature metal vapor and the deep-penetration effect of keyhole during welding,a composite heat source model applying to magnesium alloy,which was made up of Gaussian surface source and cone body source,was developed.By the different valuation to the power coefficients of Gaussian surface source and cone body source,the various focus states of electron beam were simulated to get the welding temperature fields.And then,the simulation results were favorable for the shape calculation to keyholes and welds.The experimental results show that the simulation results have good consistency with the experiment welds.