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针对激光深熔焊特点,采用均匀体热源模型、双椭球热源模型和组合热源模型,对TC4钛合金CO2激光深熔焊的焊缝形貌和残余应力进行了数值与实验研究。结果表明:在进行激光焊缝形貌与残余应力计算中,须根据激光焊接线能量选择激光热源模型,由此提出了均匀热源模型适合较大线能量,双椭球热源模型适合中等线能量,而组合热源模型适合较小线能量选择原则。组合热源模型和双椭球热源模型均能体现热输入随深度的递减变化,熔池轮廓呈现“圆锥”形和“钉子”形,均匀体热源的上下表面的残余应力分布基本一致,而双椭球热源和组合热源模型的下表面残余应力明显低于上表面。
According to the characteristics of laser deep penetration welding, the weld morphology and residual stress of TC4 titanium alloy CO2 laser deep penetration welding were studied numerically and experimentally by using homogeneous body heat source model, double ellipsoidal heat source model and combined heat source model. The results show that laser heat source model should be selected according to laser welding line energy in the calculation of laser weld morphology and residual stress. Therefore, a homogeneous heat source model is suitable for large line energy, double ellipsoid heat source model is suitable for medium line energy, The combined heat source model is suitable for the principle of smaller line energy selection. Both the combined heat source model and the double ellipsoidal heat source model can reflect the decreasing of heat input with depth, and the contour of the weld pool presents “conical” shape and “nail” shape. The residual stress distribution of the upper and lower surfaces of the homogeneous body heat source is basically the same , While the lower surface residual stress of the dual ellipsoidal heat source and combined heat source model is significantly lower than the upper surface.