Effect of Shot Peening on the Surface Oxidation of P92 Steel in the Steam Environment at 600 °C

Abstract The effect of shot peening on oxidation behavior of P92 steel was investigated under the steam environment of 600 °C. Evolution of microstructure, hardness and residual stress under different air pressure of shot peening were discussed. On the shot peened surface, a stable hematite outer layer was detected by using scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) analysis. The increased oxidation resistance of hematite layer was ascribed to the increased outward diffusion of Cr and the decreased inward diffusion of oxygen. In addition, the role of residual stress in the oxygen diffusion was discussed.