Effect of single/multi-particle grinding parameters on surface properties of bearing steel GCr15

Abstract

Grinding surface residual stress (RS) has an important influence on the service life of parts. In this study, the mathematical model of grinding force (GF) and grinding temperature (GT) of single particle was established. The relationship between grinding parameters, grinding force-thermal coupling and residual stress of single particle was analyzed by numerical simulation. Meanwhile, aiming at the multi-grain grinding of aviation precision high-speed bearing rings, the experimental analysis of crystal fragmentation, element content and residual stress of service and non-service bearing rings were carried out. Based on the above, the following results were obtained: in the simulation, the residual stress in the Y direction > the residual stress in the X direction > the residual stress in the Z direction at the same grinding force and grinding temperature. In the experiment, (1) The grain size of bearing raceway before service was about 24 μm, and the grain size of bearing raceway after service was about 3 times smaller than that before service. (2) C, Si, Cr and Fe decreased by 0.83 %, 0.07 %, 1.09 % and 32.75 % respectively after crushing (after service). On the contrary, it increased 0.66 % O and 34.08 % Pr. The Pr element was mainly distributed in the broken grain boundaries. (3) After service, the tangential residual compressive stress decreased by 169.3 MPa, while the axial residual stress increased by 172.6 MPa.

Keywords

• Single/multi grain
• Thermodynamic coupling
• Residual stress
• Bearing ring
• Crystal crushing