The Impact of Induced Shot Peening Residual Stresses on Metallic Components of SAE 1020 Steel

An experimental study on the distribution of residual stresses induced by shot peening on samples of SAE 1020 steel with pre-existing compressive stresses is presented. Two samples with similar geometries were subjected to a heat treatment to relieve stress. Then, one of the samples was subjected to a cementation process to introduce compressive residual stresses. Both samples, with and without cementation, were subjected to the same shot peening treatment. Using X-ray diffraction and electrolytic polishing to remove superficial layers, the depth-resolved residual stress distribution was obtained. It was concluded that the effect of pre-existing compressive stresses should be considered as a factor that influences the final distribution of the residual stresses induced by shot peening, namely the maximum of shot peening induced residual stresses moves closer to the surface in a sample with large initial compressive stresses and its value is greater than the maximum value for a specimen with lower initial compressive stresses.
Keywords: Shot peening, residual stresses, X-ray diffraction.