载流摩擦副的电弧损伤机制研究

发布时间：2019-03-24 11:04

【摘要】：载流摩擦副是具有载流功能的摩擦副,广泛运用在轨道交通、电力、电子、控制等领域。随着科技的发展,载流摩擦副的服役工况越来越苛刻,原有技术无法满足我国相关领域的需要,已经制约了相关领域的发展。本文以纯铜、电力机车用铜基粉末冶金滑板材料、浸铜碳滑板材料和Cu-石墨材料为销试样,与QCr0.5材质盘试样配副开展铜基材料载流摩擦学研究。对载流摩擦学特性的研究表明,载流特性与摩擦磨损特性耦合作用,表现为,电因素导致配副的摩擦磨损性能大幅度恶化,且随着电流的增加,磨损率增大;摩擦条件导致载流质量下降,且随着摩擦条件的恶化,载流质量下降幅度增大;通过回归分析发现,电流、速度和载荷是磨损率与载流效率的重要影响因素,且对二者影响大小的排序不同,三因素的影响相互耦合作用;动态摩擦系数和动态电流存在一定程度的对应关系,具有耦合作用关系。对载流摩擦过程中伴生电弧的过程及其对载流摩擦影响的研究表明,电弧萌生于摩擦界面,持续时长为毫秒级甚至更短,电弧的萌生、发展和湮灭过程具有时空随机性和动态性,随机性表现包括起弧地点随机、燃弧时长随机、电弧强度随机,动态性包括弧柱有沿摩擦切线方向运行的趋势,具体过程有波动,电弧强度有波动;电弧与摩擦磨损特性和载流特性存在一定关系。对载流摩擦过程中破坏机制的研究表明,材料损伤与导电品质恶化耦合作用,且二者的作用存在不均匀性。材料的损伤形式除常见的干摩擦损伤形式外,电因素导致材料损伤形式发生变化,还直接造成材料损伤,表现为,摩擦面温度大幅度升高,材料氧化严重,表层和次表层金属塑性流动幅度增大,表面严重粗糙化,电弧在表面造成严重的熔融和喷溅。载流摩擦过程中,材料损伤的不均匀性表现为,靠近磨损面的入口处主要是机械损伤,靠近出口处主要是电损伤,且随着电因素和摩擦条件恶化,电损伤相对增加,机械损伤相对减少。相对滑动恶化载流摩擦副的导电品质,随着摩擦条件的恶化,导电品质恶化加剧。载流摩擦副的主要导电方式为接触导电和电弧导电,靠近磨损面的入口处主要是接触导电,靠近出口处主要是电弧导电,且随着电因素和摩擦条件恶化,接触导电相对减少,电弧导电相对增加。依据损伤机制开发了Cu-石墨材料,在摩擦表面形成连续-自生-导电-润滑膜,使配副运行平稳,抑制了电弧及其危害,实现了载流摩擦特性与摩擦磨损特性的同步改善。对于载流摩擦学性能耦合作用关系方面的研究结果对抑制电弧损伤技术有指导意义,材料开发方面的工作有望为载流摩擦副的合理选材提供技术支持。
[Abstract]:Current-carrying friction pair is a friction pair with current-carrying function. It is widely used in rail transit, power, electronics, control and other fields. With the development of science and technology, the service conditions of current-carrying friction pairs become more and more demanding, and the original technology can not meet the needs of related fields in our country, which has restricted the development of related fields. In this paper, copper-based powder metallurgy slide materials for electric locomotives, copper-impregnated carbon slide materials and Cu- graphite materials as pin samples were used to study the current-carrying tribology of copper-based materials with QCr0.5 plate test pairs. The research on the tribological characteristics of current-carrying shows that the coupling effect of current-carrying characteristics and friction-wear characteristics shows that the friction and wear properties of the matching pairs are greatly deteriorated by electric factors, and the wear rate increases with the increase of current. The friction condition leads to the decrease of the current carrying mass, and with the deterioration of the friction condition, the decreasing extent of the current carrying mass increases. Through regression analysis, it is found that current, velocity and load are important factors affecting wear rate and current carrying efficiency, and the order of influence is different, and the influence of three factors is coupling each other. There is a certain degree of correspondence between dynamic friction coefficient and dynamic current, and there is a coupling relationship between dynamic friction coefficient and dynamic current. The study on the process of associated arc and its influence on current-carrying friction shows that the arc sprouts at the friction interface and lasts for nanosecond or even shorter, and the arc initiation. The process of development and annihilation is spatio-temporal and dynamic. The randomness of the process includes the random location of the arc, the random duration of the arc, the random intensity of the arc, and the tendency of the arc column to move along the direction of the friction tangent, and the specific process is fluctuating. The arc strength fluctuates; There is a certain relationship between arc and friction and wear characteristics and current-carrying characteristics. The research on the failure mechanism in the process of current-carrying friction shows that the coupling effect between the damage of the material and the deterioration of the conductive quality, and the inhomogeneity of the action between the material and the conductive quality. In addition to the common dry friction damage forms, the electrical factors lead to the change of the material damage forms, but also directly cause the material damage. The results show that the friction surface temperature increases greatly and the material oxidation is serious. The plastic flow range of the surface and subsurface metal increases, and the surface is severely roughened, and the arc causes serious melting and spatter on the surface. In the process of current-carrying friction, the non-uniformity of material damage is mainly mechanical damage at the entrance near the wear surface and electrical damage near the outlet, and with the deterioration of the electrical factors and friction conditions, the electrical damage increases relatively. Mechanical damage is relatively reduced. The relative sliding worsens the conductive quality of the current-carrying friction pair, and with the deterioration of the friction conditions, the conductive quality of the current-carrying friction pair worsens. The main conductive modes of the current-carrying friction pair are contact conduction and arc conduction. The contact conduction is mainly at the entrance near the wear surface and the arc conduction near the outlet. With the deterioration of electrical factors and friction conditions, the contact conductivity decreases relatively. The electric conductivity of the arc increases relatively. According to the damage mechanism, the Cu- graphite material was developed, and continuous-in-situ-conductive-lubricating film was formed on the friction surface, which made the matching pair run smoothly, inhibited the arc and its harm, and achieved the simultaneous improvement of the friction and wear characteristics of the current-carrying and friction-wear characteristics. The results of the study on the coupling relationship between current-carrying tribology and performance are of great significance to the suppression of arc damage, and the development of materials is expected to provide technical support for the reasonable selection of materials for current-carrying friction pairs.
【学位授予单位】：机械科学研究总院
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH117.1

【共引文献】