Mathematical model for estimation of strength and weld bead geometry of dissimilar metal laser welds

The paper aims to propose mathematical model for predicting weld bead geometry and strength for dissimilar weld joints made of galvanized iron and stainless steel. The Analytical Hierarchical Process is used to identify significantly affecting process parameters on weld joints. The experiments are conducted to weld dissimilar metal sheets using Nd: YAG laser welding machine by considering the parameters obtained from central composite design matrix. The weld samples were prepared for measuring weld bead geometry and tested for tensile strength as per ASTM E8 standards. The responses are further processed for obtaining optimal condition using Genetic Algorithm and Fuggy Genetic Optimization techniques are also compared with experimental results. The laser power, welding speed, and pulse duration are identified as significantly affecting parameters and laser power outranks among others. The proposed models predict results accurately greater than 85.29% in comparison with experimental results. The proposed model developed for predicting depth of penetration and ultimate tensile strength provides accurate results up to 8.03%, whereas 12.83% for bead width as compared to genetic algorithm and Fuzzy Genetic Optimization. The proposed model revealed 4.15% accurate results as compared to the experimental results. Mathematical models are useful for setting the process parameters and for obtaining the desired weld quality and characteristics in dissimilar metal weld joints.