Contact fatigue failure is the main form of bearing normal failure. Rolling bearing operation, rolling element in the bearing outer ring raceway and rolling, the contact part under cyclic alternating load, more per minute up to hundreds of thousands of times, repeatedly in the periodic alternating stress under the surface contact fatigue spalling occurs. When the rolling bearing starts to peel, it will cause the vibration and noise of the bearing to increase, and the working temperature will rise sharply, resulting in the final damage of the bearing. The failure form is called contact fatigue failure. Therefore, it is required that the rolling bearing steel should have high contact fatigue strength.