Fatigue Damage Evolution and Failure of G13Cr4Mo4Ni4V Bearing Steel under Heavy Load Rolling Contact

As one of the important basic components of aeroengines, bearings can provide structural support and reduce friction torque for the rotary shaft system. G13Cr4Mo4Ni4V high-temperature bearing steel is widely used in aeroengine main shaft bearings, and has excellent contact fatigue strength. The rolling contact fatigue (RCF) test is an important indicator to measure the performance of bearing steel. Compared with basic material performance experiments, such as tension and compression fatigue experiments and rotational tensile fatigue experiments, because it is similar to the real load conditions of the bearing, the test is more suitable as a guide for material heat treatment and processing process optimization in bearing processing. In order to obtain the RCF damage characteristics of G13Cr4Mo4Ni4V high-temperature bearing steel under heavy-load lubrication, the ball-on-rod RCF testing machine was used to study the fatigue damage evolution and failure behavior of the bearing steel, and its failure mechanism was preliminarily analyzed. The three-dimensional topography of the contact track of the rod was measured with a white light interferometer, combined with the analysis of mixed elastohydrodynamic lubrication, the evolution law of the lubrication behavior in the contact area and its influence on the fatigue failure behavior of the surface layer and the near-surface layer were obtained. The microstructural components and organizational topography of the material in the subsurface layer and its crack source area were analyzed through OA, SEM and EDS, and the cumulative damage and failure behavior of the material organizational structure were studied. By analyzing the lubrication behavior of the contact area, the material microstructural components, microstructure topography of the near-surface and sub-surface layers and their crack source areas, the mapping relationship between the evolution of the lubrication state and the cumulative damage of near-surface inclusions and sub-surface materials were explored. The research results showed that the lubrication state of the contact track of the test rod changed with the change of the contact surface topography at different operating stages, and the changes in the lubrication state would affect surface damage behaviors such as surface wear and micropitting. Inclusions in the near-surface layer caused the Von Mises stress to exceed the yield limit of the material, causing cracks to initiate and promoting RCF in the near-surface layer. The cumulative damage to the subsurface material structure was the main factor causing the RCF of the subsurface layer. The competition mechanism and interaction between changes in lubrication state, near-surface inclusions, and cumulative damage to the subsurface material structure were the main factors causing different RCF failure forms. This study provided the first detailed analysis of the fatigue damage evolution and failure behavior of G13Cr4Mo4Ni4V bearing steel, providing data for screening materials and processes in bearing manufacturing.