Effect Of Strengthening Grinding Process Of Steel Balls On The Fretting Wear Performance Of GCr15 Bearing Steel

With the implementation and promotion of the"double carbon"goal and the"Made in China 2025"strategy,the Chinese high-end equipment manufacturing industry has entered a period of rapid growth.Bearings are a critical component in precision machinery,which are often described as the"joints of high-end equipment."However,under the action of alternating or vibrating load,temperature,pollution level,and lubricating medium,fretting wear easily occurs between the bearing steel ball and the raceway surface,leading to fracture and failure of critical components.To solve this problem,a new centrifugal steel ball strengthening and grinding processing technology is proposed in this paper,which involves the addition of small-diameter ceramic ball particles or grinding powder and a strengthening liquid to the ball milling tank.The GCr15bearing steel balls were subjected to strengthening,grinding,and modification treatment.By modeling,simulation,and experimentation,the impact contact stress between the planetary ball milling tank and the steel balls was calculated and analyzed using dynamics and Hertz theory.The strengthening mechanism of steel balls was systematically studied,and the process parameters were optimized.Furthermore,the contact status and wear morphology of the worn area were analyzed to investigate the fretting wear performance of GCr15 bearing steel balls after modification.Theoretical support was provided for the strengthening mechanism of steel balls and fretting wear resistance.The main research contents and conclusions are as follows:（1）The dynamic impact process between ceramic balls and steel ball surfaces was modeled and simulated by varying the self-rotation and revolution of the ball mill,both with and without a lining plate.The results indicated that the ball milling tank with a lining plate exhibited better strengthening effects.As the self-rotation and revolution increased,the residual compressive stress on the surface layer significantly increased（reaching a maximum of-580.1MPa）.（2）Based on the analysis conducted using the L₉（3³）orthogonal method of three factors and three levels,the results showed that the A9 experimental group,after strengthening and grinding processing,exhibited the finest grain size and optimal dislocation density.It also had the highest microhardness（927.5 HV）,which was a 35%improvement compared to the blank control group A0（without strengthening and grinding processing）.Compared to other groups,the A9 experimental group had the maximum strengthening layer thickness（128.7μm）.The（3）Optimized process parameters for self-rotation speed,time,and ball-to-material ratio were determined as 450 rpm,2 hours,and 30:1,respectively.（4）An experimental study was conducted to investigate the fretting wear of GCr15 bearing steel balls before and after the steel ball strengthening grinding process with different displacement amplitudes of 10μm,20μm,and 60μm.The results showed that the A9experimental group had the lowest energy wear coefficient.The average friction coefficient was reduced by 15.79%,18.92%,and 6.85%compared to the blank control group A0,respectively.As the displacement amplitude increased,the wear curves transformed from an approximately linear shape to an elliptical shape,eventually transitioning to a parallelogram shape.The wear mechanism changed from adhesive wear to abrasive wear,ultimately transitioning to abrasive wear and oxidative wear.Among them,the A9 experimental group exhibited the best stability against fretting wear.The comprehensive research above indicated that there was a positive correlation between grain refinement,dislocation density,microhardness,strengthening layer thickness,residual compressive stress,and the resistance to fretting wear of GCr15 bearing steel balls.