Abstract: In order to study the residual stress field of the target caused by multi-particle impact of microparticle shot peening, a 7-particle impact model with 6 particles distributed around the center particle was established. The effect of shot peening parameters such as overlap rate, impact velocity, impact angle and particle size on the residual stress field at the center of the impact crater was simulated by finite element software. The results show that when the overlap rate ζ≤0.5, the change of ζ has no effect on the depth of residual compressive stress field, but ζ=0.75 is the boundary of surface residual compressive stress S_S changing. Only when ζ＞0.75, the four characteristic values of residual compressive stress field increase with the increase of overlap rate. Increased diameter and reduced impact angle are beneficial to increase the depth of residual compressive stress field, but also to reduce the residual compressive stress. The depth of residual compressive stress field increases with the increase of impact velocity, while the magnitude of residual compressive stress field fluctuates to a certain extent, but both of them reach the maximum when the impact velocity is 200 m/s.

Key words: microparticle, shot peening, target material, residual stress field