ISSN   1004-0595

CN  62-1224/O4

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转速对铜锡合金载流滚滑摩擦磨损行为的影响

Rotary Speed on the Current-carrying Rolling-sliding Friction and Wear Behavior of Copper-tin Alloy

  • 摘要: 针对电气化铁路滑动弓网摩擦副磨损突出的问题,提出采用滚动弓头代替滑动弓头,将受电弓与接触线的两维滑动转变为滚滑运动,从而降低磨损. 采用自主研制的滚滑摩擦试验机开展了不同转速下的铜锡合金摩擦副的载流滚滑摩擦试验研究,利用白光干涉三维形貌仪、光学显微镜(OM)、扫描电子显微镜(SEM)、电子探针(EPMA)、X射线光电子能谱仪(XPS)对损伤区进行表征,结合接触电阻(ECR)和摩擦系数演变曲线揭示载流滚滑摩擦损伤机制,并对比其减磨效果. 研究结果表明:载流滚滑摩擦下的接触电阻演变分4个阶段:初始上升阶段、下降阶段、平稳阶段和二次上升阶段. 初始上升阶段的最大接触电阻为35 mΩ,二次上升阶段的最大接触电阻随转速的增加而增大. 相较于载流滑动磨损,滚滑接触可以显著降低摩擦副损伤,磨损深度从130 μm降低到6 μm,主要磨损机制由磨粒磨损转变为剥层和氧化磨损. 随着转速的增加,接触区的材料剥落和氧化程度逐渐加剧,表面粗糙度(Ra)先减小后增大,表面最大粗糙度为1.00 μm,损伤区CuO含量上升.

     

    Abstract: Under long routing, high current and variable load, sliding friction leads to serious wear and poor stability of the pantograph-catenary contact tribo-pairs of electrified railway, which is one of the key factors restricting the development of rail transit. In this study, an innovative structural design of pantograph roller is proposed to transform the bidirectional sliding in current-carrying friction and wear problems into a two-dimensional composite friction motion of rolling and sliding, thereby reducing the reducing wear. However, most studies mainly focus on current-carrying sliding wear and current-carrying rolling wear under a single motion mode, and the researches on pantograph roller mainly focus on theoretical analysis and simulation research, and lack systematic investigate on current-carrying rolling friction and wear behavior, structural design and material matching. In this study, based on the analysis of the rolling-sliding motion relationship between pantograph roller and catenary system, the current-carrying rolling-sliding friction test system was developed, and the effect of rotary speed on the current-carrying rolling-sliding friction and wear behavior of copper-tin alloy was investigated. The innovative current-carrying rolling-sliding friction tester can accurately load normal loads, sliding and rolling speeds, and capture friction force and contact resistance in real time. The white light interferometer, OM, SEM, EPMA, and XPS were employed to evaluate damage zone, and the evolution curves of ECR and friction coefficient were analyzed to reveal the current-carrying rolling-sliding friction damage mechanism, and the wear reduction was discussed. The research results could provide data reference for controlling the wear of sliding tribo-pairs. The results showed that the ECR evolution of current-carrying rolling-sliding friction could be divided into four stages: initial ascend stage, descend stage, stable stage, and second ascend stage. The maximum ECR of the initial ascend stage was 35 mΩ, and the maximum ECR of the second ascend stage increased with the increase of the rotary speed. The friction coefficient curves could be divided into three stages: initial stage, ascend stage, and stable stage. The friction coefficient of stable stage was around 0.6~0.8. Compared with current-carrying sliding wear, rolling-sliding contact could significantly reduce wear loss, the maximum wear depth reduced from 130 μm to 6 μm, and the main damage mechanism changed from abrasive wear to delamination and oxidation wear. With the increase of rotational speed, the degree of material delamination and oxidation in the contact zone gradually increased and the surface roughness first decreased and then increased, the maximum surface roughness was 1.00 μm, and the CuO content in the damage zone increased.

     

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