重载工况下车轮熔覆对轮轨磨损与损伤性能影响

Effect of wheel cladding on wear and damage property of wheel/rail under heavy-haul condition

利用CO2多模激光器在车轮试样表面获得Co基合金熔覆层，通过 MMS-2 A 微机控制摩擦磨损试验机对比研究了不同轴重下轮轨试样的磨损性能与损伤机理.结果表明，车轮试样激光熔覆处理后熔覆层组织明显细化，表面硬度明显提高，约为基体的1．5倍.轮轨试样摩擦系数与磨损率随轴重增加而增大，车轮磨损率仅为钢轨的1/5~1/8；随时间增加，轮轨试样磨损量呈线性增长趋势；随轴重增加，轮轨试样表面损伤越严重，相同条件下，车轮试样损伤比钢轨轻微，轴重较小时，车轮熔覆层磨损主要为粘着磨损和氧化磨损，钢轨主要为疲劳磨损与氧化磨损.随轴重增加，轮轨试样主要为严重疲劳损伤，氧化磨损较为轻微.

Laser cladding Co-based alloy coating on surface of wheel/rail specimens by CO2 multimode laser.The wear property and damage mechanism of wheel/rail were investigated using a MMS-2A rolling wear testing apparatus.The results indicate that the organizations of coating layers are obviously thinner than substrate.The surface hardness of wheel/rail increased significantly and was about 1 .5 times than that of substrate.With an increasing axle load,the friction coefficients and wear rate of wheel/rail specimens increased and the wear rate of wheel specimens was only 1/5-1/8 of rail specimens’.The wear volume of wheel/rail specimens linearly increased with the time increasing.The damage of wheel/rail specimens was more severe with the increase of axle load and the damage of wheel specimen was slighter than that of rail under the same condition.For coating layers of wheel,the adhesive and oxidative wears were dominating and the fatigue and oxidative wear for rail at low axle load.With an increase of axle load,serious fatigue damage was dominating for wheel/rail specimens and slight oxidative wear exists.