Numerical investigation of temperature distribution and melt pool dimension during dissimilar laser welding of AISI 304 and pure copper

In this research, the numerical simulation of the heat transfer phenomenon in dissimilar laser welding was performed. Metals of stainless steel 304 (AISI 304) and pure copper in the moving state were exposed to laser energy, and an asymmetric thermal field was obtained. The cross-sectional area of the concentrated beam and its intensity distribution were considered circular and Gaussian, respectively. Physical properties of metals, depending on temperature and thermophysical changes in the material properties, were considered. Different temperature distributions were obtained by changing various parameters, such as focal length, welding speed, and power; the obtained results were then compared with the experimental ones. The results showed that the molten pool formation was asymmetric and deviated toward the AISI 304 sheet. The heat affected zone (HAZ) was also more toward the AISI 304 sheet. The increase of the molten pool dimensions was much more significant due to the enhancement in the average power, as compared to the other parameters, thus indicating that the average power was a key factor increasing the dimensions of the molten pool. The results of the numerical simulation were consistent with the experimental results, proving their correctness.