不同滑滚比下轮轨材料损伤行为

Damage Behavior of Wheel/Rail Materials Under Different Slip Rates

在MMS-2A滚滑试验机上采用法向载荷120N(模拟轴重16t),转速500r/min,研究京沪高速铁路用钢轨U71MnK和车轮ER8配副在不同滑滚比下的材料损伤行为。利用SEM,EDX对不同滑滚比下的磨痕及剖面形貌和磨损表面元素进行分析。结果表明:不同滑滚比下摩擦因数变化趋势反映材料损伤的过程;轮轨材料的硬化程度随滑滚比增加而增加;不同滑滚比条件下的损伤机制不同:在近似滚动条件下,轮轨材料损伤较轻,主要为氧化磨损和局部剥落。随着滑滚比增加,轮轨材料损伤逐渐发展为疲劳磨损为主,并伴随氧化磨损和磨粒磨损,且磨粒磨损程度随滑滚比的增加而增加。

On the twin-disc MMS-2A roiling contact tester, the damage behavior of the friction pair of rail（U71MnK）/wheel（ER8） materials used for Beijing-shanghai high speed railway was investigated under different slip rates with the normal force of 120N（to simulate the axle mass of 16t） and the rotating speed of 500r/min. The morphology of wear surfaces, its cross-section profiles and the chemical elements on the wear surface under different slip rates were analyzed by the scanning electron microscope and the energy dispersive X-ray detector. The results show that the changing trend of the friction coefficient under different slip rates can reflect the materials damage process; the hardening degree of the rail/wheel materials goes up with the increasing of the slip rate; the damage mechanism is different under different slip rates; under the condition of quasi rolling contact, the slight damage of the wheel/rail materials can be observed and the wear mechanisms are mainly the oxidation wear and the local spalling. As the slip rate increases, the dominated wear mechanism of the wheel/rail materials is the fatigue wear accompanied by the oxidation wear and abrasive wear, furthermore, the degree of the abrasive wear also increases with the slip rate.