Investigation of dissimilar fiber laser welding of low carbon steel and stainless steel by numerical simulation

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.