Numerical Simulation Of The Effects Of Microstructure And Inclusion On Fatigue Behavior Of High-temperature Bearing Steel

As the core component of the engine,the service environment of the aircraft-engine spindle bearing is complex and harsh.The working temperature of modern aircraft-engine spindle bearing is more than 300?,and it has to work for a long time under high-speed and heavy-load environment,which have put forward high requirements for reliability and life performance of spindle bearing.With the improvement of dynamic and structural optimization design,the optimization of bearing material performance is becoming the key to improve the service performance of spindle bearing.Among them,Hightemperature bearing steel(HTBS),whose phase-transition temperature exceeds 800?,is widely used in spindle bearing because it overcomes the disadvantage that traditional bearing steel is easy to be softened under high-temperature environment due to its lower phase-transition temperature.There are three parts in HTBS,including microstructure,second-phase particle(inclusions)and micro-defects(large inclusion,void,crack).Among them,the second particle hinder the dislocation slip movement of microstructure to strengthen the performance of HTBS,but it may form large block or platy inclusions to induce microcrack initiation in the process of heat treatment or forging,which is harmful to the fatigue performance of HTBS and cause plastic flow and local overheating in microstructure.Therefore,considering the microstructure and inclusion is helpful to analyze the rolling contact fatigue(RCF)behavior of HTBS.In this article,the geometric feature of microstructure and inclusion are extracted by image reconstruction based on the measured microstructure-and-inclusion image data of HTBS,and an efficient mixed reconstruction scheme of microstructure and inclusion is proposed,and VFEM is established based on ANSYS.Considering the external factors like surface morphology,lubrication state,working condition and dynamic contact heat,the isothermal elastoplastic RCF behaviors of HTBS were studied,involving the estimation of the fatigue life of HTBS,the simulation of brittle failure of carbide inclusion,and the analysis of local overheating of microstructure and inclusion..It can be concluded that the harder,larger volume fraction,smoother shape,more uniform distribution for carbide inclusion is beneficial to improve the fatigue performance of HTBS,but the hardness and volume fraction increasing is bad for the performance stability of HTBS,so it needs to consider the application and reliability requirement of HTBS.At the same time,carbide inclusions near surface will be brittle failure under the poor lubrication condition or rough surface,which will reduce the fatigue performance of HTBS and cause local overheating near contact area.Therefore,it is necessary to control the surface morphology and lubrication state of the contact surface of bearing components.This article proposed an interactive design idea combining with bearing working condition,lubrication state,material characteristics and dynamic contact heat,to provide theoretical indexes for material heat treatment,nondestructive testing quality control and the basic database of HTBS in aviation industry.