Influence of laser peening parameters on residual stress field of 304 stainless steel

A nonlinear elastic-plastic finite element method is established to predict the residual compressive stress distribution induced by laser peening (LP) in AISI 304 stainless steel. The dynamic material property at a high strain rate (10⁶/s) is considered when building the two-dimensional finite element model. Effects of the laser power density, laser spot size, laser pulse duration, multiple LP processes, and one-/two-sided peening on the compressive stress field in the stainless steel are evaluated for optimizing the process. The numerical results have a good agreement with the data by x-ray diffraction method, and the compressive stresses induced by LP are greater than the tensile residual stresses that result from the welding process. Peening, in general, is an effective method for protecting stainless steel weldments against stress corrosion crack (SCC). The present work provides the basis for studying the mechanism on enhancing the SCC resistance in the weld joint of Type 304 stainless steel by LP.