Effect of Shot Peening on Surface Properties of 23Co14Ni12Cr3Mo Ultra High Strength Steel

The effect of shot peening on the surface properties of 23Co14Ni12Cr3Mo ultra-high strength steel was studied. Scanning electron microscope and white light interferometer were used to analyze the effect of shot peening on the surface morphology, roughness, hardness, residual stress and element content of the samples. The results show that after shot peening, a large number of craters remain on the surface of the samples, resulting in obvious plastic deformation. The surface roughness is increased, and the arithmetic mean roughness is 1.33 μm. The hardness is significantly increased, the hardness of the outermost layer is increased from HV 476 before shot peening to HV 497, and the depth of hardened layer is about 150 μm. The residual compressive stress value of the surface layer of the sample is increased from 375 MPa to 475 MPa, the maximum residual compressive stress value is about 518 MPa, located at a depth of 50 μm from the surface, and the residual compressive stress layer formed by shot peening has a depth of about 134 μm. The mass fraction of C, Si, Cr and other elements in the sample after shot peening increased slightly. Shot peening improves the surface properties of 23Co14Ni12Cr3Mo steel material to a certain extent, which is beneficial to its fatigue resistance and corrosion resistance.