滑动摩擦条件下电弧的产生及其对载流摩擦磨损性能的影响

发布时间：2019-01-23 13:53

【摘要】：本文以铜基粉末冶金材料/铬青铜为摩擦副，模拟电力机车受电弓滑板/接触网系统的服役条件，在HST-100载流摩擦磨损试验机上进行载流摩擦磨损实验，研究了电力机车弓网系统在运行过程中产生电弧不同类型。并探讨了材料成分、电流、载荷、滑动速度以及摩擦副表面几何形貌对各类电弧产生以及摩擦磨损性能的影响。利用扫描电子显微镜(SEM)、三维形貌仪、能谱仪(EDS)等仪器对销试样摩擦表面形貌进行了表征分析，同时探讨了不同参数对各类电弧产生的影响。研究结果表明，随着接触载荷的逐渐增大，摩擦系数逐渐降低而磨损率则呈现先降低后升高的趋势，载流效率因为载荷的增加而升高，同时摩擦过程中电弧的起弧率也是先降低后升高。因此在电力机车运行过程中，，弓网间接触载荷存在一个最佳值，载荷过小弓网间接触不稳定，容易产生电弧，载荷过大则会导致磨损的加剧。随着摩擦速度的增大，摩擦系数和磨损量都呈增大趋势，同时载流效率在低速时较高且相对比较稳定，但随着速度的提高，由于冲击的加剧载流效率则急剧降低；起弧率随着速度的提高而提高。随着电流密度的增大，摩擦系数逐渐降低，摩擦过程中电弧率及磨损率逐渐升高，同时在摩擦过程中载流效率也逐渐降低，在此过程中电弧烧蚀对磨损的影响起着决定作用。随着Cu/C复合材料中石墨含量的提高，摩擦过程中摩擦系数逐渐降低，并最终趋于稳定，同时磨损率以及起弧率均呈现先降低而后升高的趋势，载流效率则呈现先升高后降低的趋势，这些充分说明存在一个合适的石墨含量使Cu/C复合材料在载流摩擦过程中的耐弧、耐磨损以及载流性能最好。随着表面粗糙度的降低，摩擦过程中摩擦系数先降低而后升高，磨损率逐渐降低，摩擦过程中起弧率逐渐降低；由于表面接触较好在摩擦过程中载流效率逐渐升高并最终趋于稳定。通过对材料摩擦后表面的微观形貌进行分析表明：随着接触载荷的增大，电弧烧蚀得到有效地抑制；当摩擦速度大于25m/s时，摩擦表面电弧烧蚀比较严重；随着电流密度的增大，粘着磨损在磨损中占据了主导作用；在一定的范围内提高石墨含量可有效抑制电弧的产生，减轻电弧烧蚀；随着摩擦表面粗糙度的降低，磨损中电弧烧蚀及粘着磨损得到抑制，磨损机理逐渐转化为磨粒磨损。
[Abstract]:In this paper, copper based powder metallurgy material / chrome bronze is used as friction pair to simulate the service conditions of pantograph slide / catenary system for electric locomotives. The current carrying friction and wear experiments are carried out on a HST-100 current carrying friction and wear tester. The different types of electric arc produced in the operation of pantograph-catenary system of electric locomotive are studied. The effects of material composition, current, load, sliding speed and surface geometry of friction pair on arc generation and friction and wear properties were discussed. The friction surface morphology of pin samples was characterized by scanning electron microscope (SEM),) and energy dispersive spectrometer (EDS). The effects of different parameters on the arc were also discussed. The results show that with the increasing of contact load, the friction coefficient decreases gradually and the wear rate decreases first and then increases, and the current carrying efficiency increases with the increase of load. At the same time, the arcing rate decreases first and then increases during friction. Therefore, there is an optimum value of contact load between pantograph and catenary during the operation of electric locomotive. If the load is too small, the contact between pantograph and catenary is unstable, and the arc is easy to be produced, and if the load is too large, the wear and tear will be aggravated. With the increase of the friction speed, the friction coefficient and the wear amount are both increasing, and the current carrying efficiency is higher and relatively stable at low speed, but with the increase of the velocity, the current carrying efficiency decreases sharply because of the aggravation of the impact. The arcing rate increases with the increase of the speed. With the increase of current density, the friction coefficient decreases gradually, the arc rate and wear rate increase gradually during friction, and the current carrying efficiency decreases gradually during the friction process. The effect of arc ablation on wear is determined in this process. With the increase of graphite content in Cu/C composites, the friction coefficient decreases gradually and tends to be stable, while the wear rate and arcing rate decrease first and then increase. The current-carrying efficiency increases first and then decreases, which fully shows that there is a suitable graphite content to make the Cu/C composites have the best arc resistance, wear resistance and current-carrying performance during the current-carrying friction process. With the decrease of the surface roughness, the friction coefficient decreases first and then increases, the wear rate decreases gradually, and the arcing rate decreases gradually in the friction process. Due to good surface contact, the current carrying efficiency increases gradually and eventually tends to stabilize during friction. The results show that the arc ablation is inhibited effectively with the increase of contact load, and the arc ablation is more serious when the friction velocity is greater than 25m/s. With the increase of current density, adhesive wear plays a leading role in wear, and increasing graphite content in a certain range can effectively inhibit the arc generation and reduce arc ablation. With the decrease of friction surface roughness, arc ablation and adhesion wear are restrained, and the wear mechanism is gradually transformed into abrasive wear.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TM501.2;TH117.1

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