Investigating sensitivity to process parameters in pulsed laser micro-welding of stainless steel foils

The laser micro-welding process plays a crucial role in advanced manufacturing industries due to a limited heat-affected zone and the ability to precisely join a wide range of materials. In this regard, this study aims to investigate the effects of pulsed laser micro-welding parameters on the thermo-mechanical specifications of 316L thin foils, a widely used industrial material, in the lap joint configuration. In this case, the influence of micro-welding speed, power, pulse duration, and frequency on the deformation, interface spot diameter, spot over-lapping, and heat-affected zone (HAZ) is analyzed by the finite element method (FEM). The numerical results are validated by comparing with foil distortion measurements. The results show that foil distortion, interface spot diameter, and HAZ are the most sensitive to the pulse duration. However, spot overlapping is mainly influenced by welding speed. HAZ dimension, a critical quality criterion of steel welding, is predominantly affected by pulse duration, welding speed, laser beam power, and frequency, respectively. Moreover, the dimensions of fusion zone, HAZ, spot overlapping, and total distortion increase by increasing the laser beam power, pulse duration, and frequency as well as reduction of the welding speed. By selecting the process parameters based on numerical analysis, it is possible to achieve desirable thermo-mechanical specifications and productivity of pulsed laser micro-welded stainless steel foils.