渗碳-激光冲击复合强化G20Cr2Ni4A磨损性能实验OA

[Objective]Bearings,known as the"joints"of mechanical systems,are irreplaceable core components and among the most failure-prone parts of wind turbine gearboxes.During service,bearing components are susceptible to surface wear,detachment,microcracks,and fracture failure.Therefore,improving the manufacturing quality of bearings and ensuring safety protection are essential for maintaining the overall stability and efficient safety of wind turbines.Currently,the low-carbon bearing steel G20Cr2Ni4A is widely used for wind power applications and is typically used as a carburized bearing material.[Methods]In this experiment,the surface of the carburized bearing steel(secondary quenching and low-temperature tempering)was further treated using laser shock peening(which emits high-energy laser pulses in nanoseconds and acts on the surface of the sample,generating plasma shock waves to cause plastic deformation of the sample surface).By refining the grain size and generating residual stress,the material's performance can be improved.As an advanced surface modification technology,laser shock peening has been successfully applied in multiple fields.After carburization and laser shock peening,the friction and wear characteristics under different wear conditions were evaluated using an M-2000 wear tester.The microstructure,microhardness,and composition were characterized using optical microscopy,scanning electron microscopy,Vickers hardness test,and energy-dispersive spectroscopy.Finally,Abaqus was used to simulate parameters such as wear volume and stress.[Results]The matrix structure of the G20Cr2Ni4A bearing steel is granular bainite,and the carburized layer is mainly composed of cryptocrystalline martensite and granular carbides.After laser shock peening,the surface composition is the same as that of the carburized layer,but severe plastic deformation occurs.Under different load conditions,the friction coefficient and wear mass of the carburized layer are significantly lower than those of the substrate.After laser treatment,the hardness of the carburized layer increases significantly,the friction coefficient decreases by 40%,and the wear mass is reduced by 26%.The substrate primarily exhibits oxidation wear and peeling,indicative of severe wear.In contrast,after combined laser and carburizing treatment,the dominant wear mechanism shifts to abrasive wear.Furthermore,laser shock strengthening enhances work hardening and induces residual compressive stress,increasing surface hardness and further improving wear resistance compared with carburizing alone.[Conclusions]This indicates that laser peening treatment technology can significantly improve the wear performance of bearing steel.The deviation rate between Abaqus simulation results and the experimental data is within 6%,indicating that the established finite-element model has high accuracy and can effectively simulate the actual wear process.The simulation results for stress and wear scar morphology show that the substrate material exhibits a high surface stress concentration during the wear process,and that the depth of the wear scar increases with increasing load.The stress distribution in the carburized and laser-treated layers is more uniform,and the wear scar morphology is smoother,especially in the laser-treated layer.Through this experiment,students have gained a deep understanding of the application of wind power bearing steel in major national projects.They have learned to improve the wear performance of materials through surface treatment technology and to comprehensively evaluate it through a combination of experiments and simulations.This has improved students'professional competence,problem-solving skills,and independent thinking.