The Research On Rolling Fricton And Wearing Properties Of The Wheel-Rail Material Under Different Loads

With the rapid development of national railway line for mixed passenger and freight, the rolling contact fatigue and wear of wheel-rail become more and more serious. As a result, enhancing investigation on the formation of wheel-rail fatigue and wear mechanisms, factors and preventing measures of wheel-rail damage can provide important guidance for the development of heavy-load and high-speed railway and the proposal of preventive measures of wheel-rail damage.In this paper, damage mechanism of heavy rail was studied by means of the macro and micro analysis of heavy-load rail damage behavior. The rolling contact friction and wearing properties of the wheel-rail material under different loads were investigated by using a JPM-1B rolling contact fatigue testing apparatus. The finite element simulation software ABAQUS was used to simulate experiment. Through the above work, the results of paper were as following.(1) The severe damages on heavy-haul rail were shown as following:spalling damage appeared on the surface of heavy-haul rail, and side wear was seen inner of the rail. The hardness analysis of cross section showed that the working hardening on the top and the side wear region of the damaged rail mainly focused on the surface of material.(2) The serious plastic deformation appeared on the top of the damaged rail. The macroscopic oblique cracks, whose propagation form was dominated by the transgranular growth, were found along the direction of plastic flow. There were slight plastic deformation and stripping damage on the side wear region. And neither plastic deformation nor macroscopic oblique cracks was found on the noncontact region.(3) With the increase of the load, friction coefficient in stable rolling friction stage would increase. Meanwhile, the wear rate of wheel/rail specimens would be intensified. According to the changing trend of wheel rail materials hardness, the thickness of wheel/rail plastic deformation layer would increase with the load increasing.(4) Under the same working condition, the depth of plastic deformation and the wear mass of wheel specimen were larger than that of rail specimen when compared with rail wheels specimen sample. The rail and wheel surface damage morphology were manifested as the typical rolling contact fatigue, and the fatigue damage of the rail was more serious. The rail and wheel surface damage morphology was dominated by fatigue cracks fracture and debris. The cracks were more likely to initiate on wheel material.(5) Regional distribution of the residual stress and the plastic deformation on the contact region could be obtained from finite element analysis. It could be concluded that cracks were most susceptible to be produced on surface and subsurface of the rail.