Abstract
The new generation of bearing steel has good comprehensive properties, which can satisfy most of the requirements of bearing steel in a complex environment. In the presented work, fatigue properties of 15Cr14Co12Mo5Ni2 bearing steel have been investigated by means of rotating bending fatigue tests on smooth bar specimens after carburization and heat treatment. Optical microscope, scanning electron microscopy, electron backscatter diffraction, and Image-Pro Plus software were used to analyze the fracture, microstructure, and carbides. The results suggest that the fatigue strength at room temperature and 500 °C is 1027 MPa and 585 MPa, respectively. Scanning electron micrographic observations on the fracture surface of the fatigue specimens at 500 °C show that fatigue cracks usually initiate from voids in the carburized case and oxide layer on the surface of steel. The failure mode in the carburized case is a quasi-cleavage fracture, and with the increase of crack propagation depth, the failure mode gradually changes to fatigue and creep-fatigue interaction. With the increase of the distance from the surface, the size of the martensite block decreases and the fracture surface shows great fluctuation.
Highlights
High-end bearings in aerospace, high-speed rail, and other fields need to have high hardness, corrosion resistance, high strength, good toughness, and other properties, but need to have high fatigue performance in high-temperature environments
The results show that the fatigue strength of the steel decreased with the increase of the test temperature
Li et al [10] studied the effects of different temperatures on the fatigue resistance and crack growth rate of TC17, and the results show that the initiation of cracks account for the majority of the fatigue life, and high temperature promoted the crack initiation and promoted the crack propagation
Summary
High-end bearings in aerospace, high-speed rail, and other fields need to have high hardness, corrosion resistance, high strength, good toughness, and other properties, but need to have high fatigue performance in high-temperature environments. Due to the addition of a large amount of Co element in steel, there are dispersed fine carbides in the matrix, so that the steel has high strength and toughness at the same time, becoming the most potential new generation bearing steel. The fatigue strength of 15Cr14Co12Mo5Ni2 bearing steel can reach 1016 MPa at room temperature [3]. In the case of stress concentration, the crack was initiated from the edge of the carbides in the carburized case and propagated along the carbides and grain boundaries where the bonding strength was licenses/by/4.0/)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
