Experimental and numerical study of melt flow, temperature behavior and heat transfer mechanisms during the dissimilar laser welding process

The influence of laser beam deviation on temperature field and melt flow during laser welding of two different metals, brass and 308 stainless steel (S.S 308), was examined numerically and experimentally in this study. The laser beam's absorbed energy was estimated using surface and volumetric Gaussian heat fluxes. While the laser beam's placement on the 308 stainless steel sheet, specifically at a distance of 0.5 mm from the joint, the simulation findings indicated that the temperature differential on the steel's surface was considerably more pronounced than the laser beam was positioned elsewhere. The molten pool's surface tension gradient and buoyancy forces are conducted to form a Marangoni flow. The low melting point of the brass alloy resulted in an enormous molten pool volume than stainless steel under a 0.0 mm beam deviation. Furthermore, the velocity of the melt flow rose by 0.0102 m/s due to an increase in temperature gradient and shear stress yielded by the laser beam's deflection towards the stainless steel sheet. Furthermore, the numerical results coordinated well with the experimental outcomes.