接触压力对碳滑板／铜接触线载流摩擦磨损性能的影响

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The effect of contact pressure on friction and wear behavior of carbon strip/copper contact wire was tested on a ring-on-block friction wear test machine under the electric current of 250 A, sliding velocity of 160 km./h and contact pressures of 50,70,90,110 and 130 N. The microstructures of strips were observed by an optical microscope. The results show that with the decrease of contact pressure, the wear surface topography of carbon strip changes from relatively smooth wear surface to wear arc ablation surface and multiple pit wear surface;the dominant wear type changes from are erosion wear to abrasive wear;the transition period of friction coefficient becomes clear and the friction coefficient in stable period is increased. The wear rate of carbon strip becomes stable with time. The wear rate in stable period is first decreased and then increased at the shape of ＂U＂ with the increase of the contact pressure. The increase of contact pressure can decrease arc discharge power and off-line rate. In consideration of the wear rate of carbon strip and the current-carrying stability, the best contact pressure is 90 N.控制电流为250A，滑动速度为160km／h，在接触压力50，70，90，110，130N下，在环一块式载流摩擦磨损试验设备上进行接触压力对碳滑板／铜接触线载流摩擦磨损性能的影响试验，用光学显微镜对滑块的磨损形貌进行观察。结果表明：随着接触压力的减小，滑块的磨损形貌由以较光滑磨损面为主过渡到以受电弧飞溅影响磨损面和多麻坑磨损面为主，主要磨损形式由磨粒磨损过渡到电弧烧蚀磨损，摩擦因数的过渡阶段逐渐明显，稳定阶段的摩擦因数逐渐增大；碳滑板的磨损率随着试验的进行进入稳定期，稳定期磨损率随着接触压力的增加先减小后增加，呈“U”形分布；接触压力的增加可以降低电弧功率和离线率；从碳滑板的磨损率和载流稳定性综合考虑，90N为最佳接触压力。