Effects of different shot peening parameters on residual stress, surface roughness and cell size

Abstract

Shot peening is widely used to strengthen the surface of metal parts, and its effect is affected by various parameters, such as shot peening coverage, peening intensity, peening velocity, shot size and shot material. In this study, a random multi-shots model which incorporated dislocation density-based constitutive equations was established. With the developed model, the effects of peening velocity, peening coverage and double peening on the surface integrity in terms of the residual stress, surface roughness and dislocation cell size were analyzed. The simulated results show that increasing the peening velocity can significantly thicken the refining layer and the compressive residual stress layer (CRSL), and deepen the location of the maximum compressive residual stress (MCRS). Meanwhile, increasing the peening coverage can heighten the magnitude of MCRS in subsurface, but hardly affects the surface compressive residual stress (SCRS) and the thickness of CRSL. Compared to simply pursuing the improved peening velocity and enhanced coverage, the use of an appropriate double peening process can induce a larger SCRS while reduce the surface roughness slightly.