Study On Key Influencing Factors And Mechanism Of Wear Behavior Of Typical Wheel Steel

As the driving force of economic development,the driving force of social development and the main mode of transportation,high-speed railway has attracted more and more attention at home and abroad.With the continuous updating of vehicle models of high-speed trains,problems in wheel rail system and other aspects emerge one after another in the process of train operation.At this time,the research on the key influencing factors of wheel rail wear performance and the evolution mechanism of wheel organization during train operation is of great significance to the development of high-speed railway transportation industry.In this paper,ER8,D2 and SSW-Q3R of three typical high and medium carbon wheel steels are selected to study the influence of different factors on wheel wear performance through rolling friction and wear test.The four factors of material,axle load,running speed and slip are analyzed and studied by orthogonal optimization method,and the surface macro observation and section microstructure evolution of the samples after wear test are analyzed Comparative tests were carried out on wheel steels of different materials under the same test conditions.The best test parameters obtained through orthogonal wear test were selected.Under this test condition,2×10~5 r wear tests were carried out.The wear amount,friction coefficient,section hardness,section microstructure and surface morphology were analyzed and compared.The results show that when the wear rate is taken as the parameter,the material is the most influential factor on the wear performance of wheel steel,followed by slip and contact stress,and the running speed is the least influential factor.When the wheel surface hardening degree is taken as a parameter,the influence degree on the wear performance of wheel steel is material,contact stress,rotating speed and creep rate.According to the orthogonal results,whether the wear rate or the surface hardness is taken as the parameter,the material is the most critical factor.The surface structure of the three wheel steel sections after wear test can be divided into severe deformation zone,rheological zone and transition zone according to the deformation degree of ferrite and pearlite.At the same time,with the increase of surface depth,the pearlite lamella of the section structure decreases,the ferrite is refined gradually,the cementite is broken gradually,and the surface hardness of the sample increases.Among them,SSW-Q3R has the most uniform original structure,the largest thickness of severe deformation layer after wear,the highest surface hardness,the best wear performance and the lowest wear rate.In the cycles of 2×10~5 comparative test of three kinds of wheel steel,the wear amount of SSW-Q3R is the smallest,the thickness of fine grain zone is the largest and the surface hardness is the highest.