A three-dimensional numerical simulation model is developed in this paper to analyze the symmetry of weld geometry and the homogeneity of alloy distribution in the molten pool during the dissimilar fiber laser welding of low carbon steel and stainless steel during different welding conditions. The simulated results are compared with the experimental results and good agreement has been obtained. The characteristics of weld geometry, flow field and alloy distribution are analyzed based on the numerical calculation. The obtained results indicate that the weld morphology is asymmetric and the weld width is increasing gradually with the laser power increasing. The convection formed in the molten pool is enhanced under high laser power welding condition, which results in that the alloy distribution in the molten pool is more homogeneous and the difference between the upper and lower widths of the weld is decreasing. The weld morphology and alloy distribution in the dissimilar fiber laser welding can be predicted. It is clearly seen that the proposed model is effective for optimal welding process parameters selection to obtain the desired welded joints with excellent performance, which demonstrates guiding significance for improving the quality of dissimilar laser welding.

中文翻译：

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低碳钢与不锈钢异种光纤激光焊接的数值模拟研究

本文建立了三维数值模拟模型，以分析低碳钢和不锈钢在不同焊接条件下的异种纤维激光焊接过程中焊缝几何形状的对称性和熔池中合金分布的均匀性。将仿真结果与实验结果进行比较，取得了很好的一致性。在数值计算的基础上，分析了焊缝的几何形状，流场和合金分布特征。所得结果表明，随着激光功率的增加，焊缝形态不对称，焊缝宽度逐渐增大。在高激光功率焊接条件下，熔池中形成的对流会增强，结果导致熔池中的合金分布更加均匀，焊缝上下宽度之间的差异减小。可以预测异种光纤激光焊接中的焊接形态和合金分布。可以清楚地看到，该模型对于选择最佳的焊接工艺参数是有效的，以获得具有优良性能的所需焊接接头，这显示出对提高异种激光焊接质量的指导意义。