Effect of shot peening on solid particle erosion behavior of AISI420 stainless steel

The aim of this paper is to study the effect of shot peening (SP) on solid particle erosion (SPE) behavior of AISI 420 stainless steel. The mechanisms of three factors of SP, i.e., compressive residual stress (CRS), surface roughness (SR) and work-hardening on SPE resistance were investigated. The results show that the SPE resistance of the shot peened specimen is decreased at 90° impingement angle, while it is hardly affected at 30° impingement angle. However, with polishing treatment to the shot peened specimen, the SPE resistance can be improved obviously at both impingement angles. These results can be explained by follow: The high SR increases the effective area under the bunch of solid particles, so it decreases the SPE resistance of the shot peened specimen. The CRS induced by SP can increase crack closure and retard crack propagation, so it improves effectively the SPE resistance, especially at 90° impingement angle. The work-hardening improves obviously the SPE resistance of the shot peened specimen at 30° impingement angle because the micro-cutting resistance of the surface is increased. However, the work-hardening decreases the resistance of SPE at 90° impingement angle due to the poor multi-impact fatigue property of the hardened surface.