Enhancing the High‐Temperature Rolling Contact Fatigue Performance of Carburizing 8620H Steel Through Ultrasonic Surface Rolling Process

ABSTRACT To improve the rolling contact fatigue performance of 8620H steel, a new technique combining carburizing and ultrasonic surface rolling process (USRP) was developed. The optimal surface properties of USRP‐treated carburized 8620H steel were obtained by applying a rolling force of 1000 N, processing passes of six, and an ultrasonic amplitude of 10 μm. Rolling contact fatigue tests were performed on different specimens, the results showed that the characteristic life of the USRP‐treated specimen was increased by 31.0%, 53.4%, and 11.6% at 25°C, 100°C, and 150°C, respectively. At 100°C, the USRP‐treated specimen provided the highest performance improvement. This is because the surface strengthening effect can be maintained and the ability to resist plastic deformation is reduced. As a result, the contact area between the specimen and the bearing balls increases, reducing the contact stresses in the contact area.