Effect Of The Rubbing And Wearing Behavior Of Steel Rail By Ultrasonic Peening

With the improvement of the locomotive speed, and the increase in the vehicle axle load, rail contact stress, with increased tread Rails longitudinal and lateral friction and pressure rail side are larger, and cause rail wear and on the side of the vertical wear, RIM and wheel tread wear and tear will be larger. Therefore, Solve the railway industry in a number of key technical issues have great significance. Developing the rail surface wear of the Organization had important practical significance. There are more potential economic benefits On China's railway system to reduce the existing rail maintenance costs and cost. Which also achieve railway the necessity of sustainable development.In this paper, detail discuss the rubbing and wearing of steel rail and its Classification and its study of the history and current status. On this basis, to rail as a major research U70 object,the samples of U70 object was processed by TJU-UMSNT-Ⅰultrasonic surface nano-crystallization device, which is made in Welding institute in Tianjin University. Observe microstructure on the treated, Sample by Transmission Electron Microscope, determine the roughness on the treated sample by high precision inductance type rough meter, analyze the relation between the hardness and distance from surface on the treated sample by micro-sclerometer and analyze abrasion degree on the samples treated before and after by Scanning Electron Microscope.Results are as follow:The surface layer of U70 object was severely deformed after ultrasonic peening. With the increase of time, the impact of plastic deformation sample increased gradually and such a gradient structure was formed from the topmost surface to the matrix: the severely deformed layer, transition layer and matrix. On the severely deformed layer,a fiber-like microstructure was formed on the surface,and t he depth of the severely deformed layer increased with the prolonging of treatment time and finally reached a plateauat about 55μm.Compared to the sample without treatment, the rail surface hardness markedly improved, but its hardness decreased increasing with depth. When the amplitude is 24um, the longer the impact time, the greater increasing range of hardness will be. When the impact time was 60min, its surface hardness reached 613HV. Compared to the sample without treatment, its surface hardness was increased 88.6%. When the amplitude was 26.6um and the impact time was 60min, its surface hardness reached 600HV. Compared to the sample without treatment, its surface hardness was increased 84.6%.It was observed that amplitude to 24μm , Ra by the original 19.8μm down to 4.59μm. 76.8% was reduced. The wear resistance of rail steel was significantly improved through the ultrasonic impact technology. The longer the impact time, the greater increasing range of wear resistance will be. When the amplitude is 24um and impact time is 60min, the wear resistance increased most. Compared to the sample without treatment,its wear resistance increased 40.6%. The specimen with heat treatment which wear resistance increased 34.4%, when the amplitude is 24um and impact time is 60min. Residual stress also affect the wear resistance of specimen, the wear resistance can increased 6.2% when the specimen has wear resistance.