Effect of Shot Peening on the Rolling Contact Fatigue Behavior of Carburized High-Strength Bearing Steel

The microstructure, hardness gradient, residual stress,  surface roughness and rolling contact fatigue behavior of carburized and carburized + shot peening composite bearing steels of different strength were studied. The results showed that after carburizing treatment, the surface layer of the bearing steel was mainly composed of high-carbon martensitic and worm-like carbides, and the worm-like carbides were mainly M23C6, M6C, M7C3 carbides, the surface layer of carburized bearing steel undergoes plastic deformation after shot peening, resulting in the increase of the density of geometric necessary dislocation (GND) in the surface matrix (BCC phase).

Under the effect of and dislocation strengthening, the microhardness of the surface layer of the bearing steel was slightly increased. Compared with carburized bearing steel, the surface residual compressive stress of carburized + shot peening bearing steel was significantly increased, while the surface residual stress of carburized + shot peening bearing steel decreased with the increase of shot peening strength.