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针对激光深熔焊“螺钉”状焊缝截面,构造了高斯面热源和双椭球体热源叠加的组合热源模型。利用有限元分析软件ABAQUS和FORTRAN语言编写的用户子程序,实现了组合热源的加载,对激光深熔焊温度场进行了数值模拟。温度场结果表明,激光焊是快速加热和冷却的过程,且焊接工艺参数对熔池最高温度有一定影响。此外,分析了基于该组合热源模型所得的温度场与焊缝微观组织及显微硬度的关系,焊缝边缘的温度梯度比焊缝中心大,焊缝边缘处为柱状晶,而焊缝中心为等轴晶,焊缝的显微硬度比母材高。模拟所得熔池形状与试验中焊缝形状吻合较好,该模型能为激光焊工艺参数的预选和优化提供依据。
Aiming at the deep penetration laser welded “screw ” weld section, a combined heat source model of Gaussian surface heat source and double ellipsoid heat source superposition was constructed. The finite element analysis software ABAQUS and FORTRAN language user subroutines were written to realize the combination of heat source loading, and the temperature field of laser deep fusion welding was numerically simulated. The results of temperature field show that laser welding is the process of rapid heating and cooling, and the welding process parameters have certain influence on the maximum temperature of the molten pool. In addition, the relationship between the temperature field and the microstructure and microhardness of the weld seam based on the heat source model is analyzed. The temperature gradient of the weld edge is larger than the weld center, and the edge of the weld bead is columnar. The center of the weld is Isometric crystal, weld microhardness higher than the base metal. The shape of the weld pool simulated by the simulation is in good agreement with the shape of the weld in the experiment. The model can provide the basis for the preselection and optimization of the laser welding process parameters.