Microstructures and rolling contact fatigue behaviors of 17Cr2Ni2MoVNb steel under combined ultrasonic surface rolling and shot peening

摘要

A novel surface treatment method of combining ultrasonic surface rolling (USR) and shot peening (SP) in different sequences was proposed. The microstructures and rolling contact fatigue (RCF) behaviors of 17Cr2Ni2MoVNb steel were investigated after USR treatment, SP treatment and combined (USR + SP + USR) treatment. Results showed that the combined treatment can significantly generate ultra-fine grains, improve surface microhardness and induce high intensity residual compressive stress in material surface layer. The samples after combined treatment with the lowest surface roughness exhibited the maximum mean RCF life of 6.610 × 10~6 cycles and the fatigue damage mechanism was spalling.