Surface Integrity and Anti-Fatigue Mechanism of 30CrMnSiNi2A Steel with Shot Peening Treatment

Abstract

In this study, 30CrMnSiNi2A steel specimens were treated by shot peening technique. In order to evaluate the effects of shot peening process on the surface characteristics, the surface topography and roughness of the treated and untreated specimens were observed and analyzed using scanning electronic microscope (SEM) and surface profile tester. Surface microstructure and residual stress were observed and analyzed using transmission electron microscope (TEM) and X-ray stress apparatus respectively. Results show that the surface roughness of milling specimens could be reduced from Ra 4.45 μm to 2.39 μm using shot peening process. Severe plastic deformation and grain refinement were also induced by the process, and the average grain size of nano-structured regime was about 46 nm. Moreover, a 300 μm compressive residual stress layer with the -766.5 MPa compressive residual stresses was induced. At the same time, the anti-fatigue mechanism of shot peening was discussed.

Experimental Study on the Effect of Shot Peening and Re-Shot Peening on the Residual Stress Distribution and Fatigue Life of 20CrMnTi

“…The results show that the effect of shot peening on improving fatigue properties does not vary simply monotonically with shot peening intensity and coverage, and that surface integrity and fatigue resistance are relatively high within a certain range of shot peening parameters. When choosing shot peening parameters, it is inappropriate to blindly pursue high strength or shot peening coverage while ignoring the surface integrity of the metal material [26][27][28].…”