Mitigation of tensile residual stress induced during welding with laser shock processing

Laser shock processing (LSP) is proving to be a competitive technology to traditional surface enhancement techniques in engineering products. The LSP develops a significant residual compressive stress deep into the surface of a metal alloy, which is beneficial for fatigue, wear and corrosion. In this paper a comprehensive finite element analysis (FEA) model is presented to investigate the redistribution of welding residual stress processed by laser shock processing. In order to verify the FEA model, benchmark simulations are performed verified with available experimental results. Results show that predicted residual stresses agree well with the experimental data. A point to be noted from the results is that welding tensile residual stress can be modified and changed into compressive residual stress due to laser shock processing. Parametric study of influences of LSP parameters on welding tensile residual stress, such as full width at half maximum (FWHM), power density, spot size and number of shots, have been analysed. Some optimized parameters of LSP can be made by employing the results of the parametric investigations.