With the substantial improvement in the demand for aero-engine performance

the main shaft bearings are facing harsher working conditions

which cause the working temperature and load of the bearings to increase dramatically. The friction and wear problems in bearings are becoming increasingly prominent

seriously affecting the service life and reliability of high-end equipment. The above problems bring new challenges to the optimization of M50 bearing steel material for aero-engine. Although the control technology of inclusions in bearing steel has made great progress

the control of primary carbide is still the key problem in the control of bearing materials. The paper summarizes the main research hotspots on friction and wear behavior of bearing steel at home and abroad

especially the sliding wear and rolling contact fatigue failure forms during service. The advantages and disadvantages of primary carbides in bearing steel in two kinds of friction and wear behaviors are pointed out

as well as their interrelationship. And based on the existing control methods of primary carbide

the future control strategy of primary carbide in bearing steel and the development goal of improving the friction and wear resistance of M50 bearing steel are put forward.