加载系统刚度对第三轨受电摩擦磨损特性的影响

在CETRUMT-2摩擦磨损实验机上,用自行设计的夹具,研究了加载系统支撑刚度对地铁第三轨与受电靴摩擦副之间的载流摩擦磨损特性的影响,测量了法向力随时间的变化、摩擦因数以及受电靴的磨损质量损失,观察了试样磨损表面,分析了加载系统的支撑刚度与载流摩擦磨损特性之间的关系。结果表明:不同支撑刚度条件下,随着法向载荷降低,载荷振幅均增大,电弧烧蚀导致材料损失增加;弹性支撑改变了加载系统的振动特性,使得载荷振幅和磨损质量损失总体上较刚性加载时小;为保证第三轨系统良好的受流,应选择合适的加载范围和一定刚度的加载系统,降低电弧烧蚀带来的材料损失,延长摩擦副的使用寿命。     

法向压力对浸金属碳/不锈钢材料载流摩擦耦合温度场的影响

通过ANSYS有限元软件建立钢铝复合轨(不锈钢)/受电靴(浸金属碳材料)在接触电阻热和摩擦热耦合作用下的温度场模型,模拟摩擦副的载流摩擦磨损温度场分布,研究模型在不同法向压力条件下的耦合温度变化特性。结果表明:对于浸金属碳材料/不锈钢摩擦副,在位移、电流和相对滑动速度一定的条件下,随着法向压力的升高,耦合最高温度呈现出先降低再升高的特性,存在一个使得耦合温度最低的法向压力;为降低摩擦副由于温升而导致的磨损,可选此法向压力作为实际工作压力。     

载流磨损中的电弧热散失和对流换热有限元分析

载流摩擦磨损过程中电弧和磨损相互作用,使得摩擦副的材料损失严重,受流质量下降.分析电弧侵蚀和磨损之间的相互作用关系以及电弧的形成原因,基于有限元软件对地铁钢铝复合轨和受电靴在电弧下作用的温度场进行模拟,并分析其在不同对流换热系数条件下的散热过程.有限元热传导分析发现电弧在瞬间产生很高的热量,但温度最高的地方面积很小,在经过较长时间的传导,热影响区的温度也只占电弧最高温度的很小比例;对流换热系数越大,电弧热的热影响区面积就越小,而且温度也越低,可以通过加大载流摩擦系统的对流换热系数,降低电弧侵蚀对载流摩擦副的影响.     

钢铝复合轨/受电靴摩擦热与接触电阻热耦合的温度场有限元模拟研究

基于ANSYS有限元软件建立钢铝复合轨/受电靴在接触电阻热和摩擦热耦合作用下的温度场模型,给出了2种热量耦合的方法,计算了模型的温度场,研究了模型在不同电流、速度和位移条件下的耦合最高温度变化。结果显示:在相同位移和法向压力条件下,耦合的最高温度随电流的增大而增大,随速度的增大而减小;在电流、速度和压力相同的条件下,耦合最高温度随位移的增大成线性增大趋势。     

聚酰亚胺复合材料与不同金属间干滑动时的摩擦学性能

采用MPX-2000型摩擦磨损试验机研究了聚四氟乙烯和二硫化钼填充聚酰亚胺复合材料在干滑动摩擦条件下与45钢、镍铬合金、铜和铝对磨时的摩擦磨损性能,并利用扫描电子显微镜和光学显微镜分析了复合材料及对偶件的磨损表面形貌。结果表明:复合材料与铝对磨时的摩擦因数和磨损率最低,分别约为与钢摩擦时的43%和49%;摩擦后铝表面形成均匀连续的转移膜,45钢、镍铬合金和铜的表面没有形成有效转移膜,因此复合材料的摩擦因数较大;复合材料与不同金属材料摩擦时的磨损机理主要是粘着磨损与疲劳磨损。     

倾斜板铸造不同成分铝铅耐磨合金的摩擦磨损性能

采用倾斜板铸造技术制备了铝铅合金,并用扫描电子显微镜对磨擦表面的形貌和成分等进行了观察与分析,研究了合金的基本特性和不同合金元素对摩擦学性能的影响,探讨了干摩擦条件下铝铅合金与45钢对摩时的磨损机理。结果表明:与铝合金基体相比,作为软相铅、锡的加入使铝铅合金的摩擦因数降低了15%,磨损量减小了近70%;随着锡含量的增大,其摩擦因数和磨损质量呈现先减小后增大的趋势;铝铅合金的摩擦学性能优良,其磨损形式为轻度的粘着磨损、磨粒磨损和疲劳磨损的复合磨损。     

载流磨损的最佳法向载荷三维关系模型研究

以地铁第三轨受流为研究对象,试验了法向载荷对第三轨与受电靴之间载流摩擦磨损特性的影响。结果表明:载流磨损体积损失随着法向载荷的增大均呈现出现先快速减小而后缓慢增大的U形变化趋势,发现存在最佳法向压力,此压力下的磨损体积损失最小,且随着速度的增大最佳法向压力相应增大。建立了W-F-V模型(磨损量-法向压力-速度三维关系模型)能与实际的试验结果较好的吻合,研究对于载流摩擦磨损状态的预测,及最优磨损条件的选择等都具有积极的意义。     

电流对不锈钢/铜的载流摩擦耦合温度场影响

利用ANSYS有限元分析软件对钢铝复合式第三轨(不锈钢)/受电靴(铜)的耦合温度场进行模拟分析,研究了模型在不同的电流( 150-600)A条件下的载流摩擦耦合最高温度变化.结果表明:当相对滑动速度为120km/h和法向压力为150N时,耦合最高温度随电流的增大基本保持不变;当相对滑动速度为120km/h和法向压力为120N时,耦合最高温度随电流的增大先保持不变后升高;其它情况下耦合最高温度随电流的增大而升高.     

镍基Si3N4复合镀层的摩擦磨损特性

通过复合电镀法制备了N i-Si3N4和N i-P-Si3N4两种复合镀层,分别与热处理45#钢组成摩擦副,进行环-环摩擦磨损试验,测试了摩擦因数和磨损量,并观察了磨损表面形貌,探讨了摩擦副的摩擦磨损机理。结果表明,N i-P-Si3N4/45#钢摩擦副的摩擦因数较小,磨损量低,具有良好的减摩耐磨性能。镀层基体的性能明显影响复合镀层的摩擦磨损性能。磨料磨损是N i-Si3N4/45#钢摩擦副的主要磨损形式,导致45#钢的磨损量增大;N i-P-Si3N4镀层对Si3N4颗粒具有良好的把持力,避免了磨料磨损的产生,摩擦副处于稳定的边界润滑摩擦状态。     

永磁场条件下45钢与GCr15钢摩擦磨损性能试验研究

基于HSR-2M高速往复摩擦磨损试验机,研究在永磁体磁场条件下滑动速度、载荷等参数对45#钢/GCr15钢摩擦副摩擦学性能的影响,通过磨痕形貌分析其磨损机制,并与无磁场条件下的试验结果进行对比。试验结果表明:磁场的引入可以在一定程度上减小摩擦因数和降低磨损率,证明磁场能够改善45#钢/GCr15钢摩擦副的摩擦学性能;增大滑动速度将降低摩擦因数和磨损率,增大载荷将降低摩擦因数,增加磨损率。无磁场时,摩擦副的摩擦磨损为典型的磨粒磨损,磨损系统的磨损率和摩擦因数较大;有磁场时,磨损形式主要为黏着磨损,摩擦因数和磨损率较小。     

Friction and wear behaviour of stainless steel rubbing against copper-impregnated metallized carbon

A series of experimental tests were carried out using stainless steel rubbing against copper-impregnated metallized carbon under electrical current on a pin-on-disc test rig. The test parameters include the sliding speed of 60-100 km/h, normal force of 40-80 N and electrical current of 0-50 A. During testing, the friction coefficient and wear volume were recorded. The topography of worn surfaces was also observed with SEM. The cross sectional profiles of worn surfaces of stainless steel were measured with Ambios profiler. The result displays that electrical current, normal load and sliding speed have a distinct effect on the friction and wear behaviour of stainless steel rubbing against copper-impregnated metallized carbon. Without electric current, the friction coefficient is largest but the wear volume of copper-impregnated metallized carbon is lowest. With increasing electric current, the friction coefficient decreases while the wear volume of copper-impregnated metallized carbon increases. Through the whole test, it is found that the wear loss of stainless steel was light. The wear of copper-impregnated metallized carbon becomes severe when electrical current or sliding speed is high. When the electrical current or sliding speed is high, arc ablation is a dominant wear mechanism of copper-impregnated metallized carbon.     

聚合物填充聚四氟乙烯复合材料的摩擦磨损性能

采用机械共混-冷压成型-烧结的工艺制备了PEEK、PPS填充PTFE基粘弹．摩擦型阻尼材料，用环-块式磨损试验机研究了在干摩擦条件下的摩擦磨损性能；用扫描电子显微镜观察磨损表面形貌和内部组织结构。结果表明：混合填充PEEK和PPS时，2种填充物的比例对材料的摩擦因数影响不大，当二者含量相近时，摩擦因数最大；填充物对磨损性能的影响与对摩擦因数的相同；随着PEEK含量的增加和PPS含量的减少，材料的磨损方式由疲劳剥落磨损为主转变为犁削、粘着磨损；PTFE含量的增加，使得复合材料的摩擦因数减小，而磨损有所增大。综合考虑认为，PTFE与适当比例的PEEK／PPS混合填充，具有合适的摩擦因数和较好的耐磨性，能够满足特殊工况下阻尼材料的需要。     

Study on transition between fretting and reciprocating sliding wear

An experimental investigation was conducted to find the associated changes in characteristics of wear before and after the transition between fretting and reciprocating sliding wear. A set of experiments were carried out using a AISI 52100 steel ball rubbing against a plate specimen made from the same steel under dry condition. Wear coefficient, wear volume, coefficient of friction, profile of the scars and wear debris were analyzed. The results displayed that there were significant differences in wear coefficient, wear volume, profile of the wear scars and wear debris before and after the transition. Wear coefficient and wear volume at a constant sliding distance were found to be the most appropriate for identifying the transition amplitude between fretting and reciprocating sliding wear.     

Wear rate testing in relation to airborne particles generated in a wheel–rail contact

This study examines the relationship between generated airborne particles and wear rate in the wheel–rail contact. The wheel–rail contact is experimentally simulated by using pin‐on‐disc testing to determine the difference in wear rate between selected contact conditions. Wear is discussed both in tribological terms and by using the wear categories prevalent in the railway industry, namely, mild, severe and catastrophic wear. The discussion is based on wear depth, the coefficient of friction, topographical measurements and measurements of airborne particles generated in the contact. The tests were performed under selected loading conditions representative of different contact conditions in a real wheel–rail contact. The results indicate that wear rates vary with the contact conditions arising from different types of triggered wear transitions. This is emphasised by the number and size of the airborne particles generated. Copyright © 2009 John Wiley & Sons, Ltd.     

载流条件下铬青铜/3D碳/碳复合材料摩擦副的摩擦磨损性能

以3D碳/碳复合材料为销试样、铬青铜QCr0.5为盘试样进行了载流条件下的干滑动摩擦磨损试验。通过对有、无电流条件下销试样磨损量大小和摩擦因数影响度的比较,以及对销试样摩擦表面进行的微观形貌分析,结果表明,电流对铬青铜/3D碳/碳复合材料摩擦副的干摩擦行为具有显著的影响,并且由于电场、摩擦热、电弧热的共同作用,在销试样表层发生了磨粒磨损和氧化磨损。     

Tribological Behavior of Tin-Based Babbitt Alloy Lubricated by Seawater

In this article, the tribological behaviors of tin-based Babbitt alloy ZChSnSb 8–8 sliding against AISI 302 stainless steel lubricated by seawater were investigated. The results indicated that the friction coefficient decreases with increasing load and sliding speed, and the wear rate increases slightly with load but decreases with sliding speed. The low friction coefficient and wear rate are attributed to the unique “concrete structure” and seawater. As a lubrication medium, seawater has lubricating, cooling, and corrosive effects on the sliding couple.     

载流条件下铬青铜/纯铜摩擦副摩擦磨损性能研究

在自制的销盘摩擦磨损试验机上,对铬青铜/纯铜摩擦副进行载流条件下的干滑动模拟试验,研究了电流、速度、载荷对铬青铜/纯铜摩擦磨损性能的影响规律。试验结果表明:电流是影响摩擦副摩擦磨损性能最显著的因素,摩擦因数和磨损率都随着电流的增大而增大;速度和载荷对摩擦因数和磨损率也有显著影响;电流的存在,摩擦副间产生了比无电流时更严重的粘着磨损和塑性变形,同时增加了电化学腐蚀,使磨损更加严重。     

紫铜/铬青铜摩擦副在干摩擦和水雾条件下的载流摩擦磨损性能研究

在HST-100载流高速摩擦磨损试验机上,对比考察了紫铜/铬青铜摩擦副在干摩擦和水雾2种状态下的载流摩擦磨损性能,采用扫描电镜(SEM)对磨损表面形貌进行了观测。结果表明:水雾条件下销试样载流摩擦磨损时,其摩擦因数及磨损率均低于纯载流状态下;该试样在纯载流条件下的磨损机制主要为粘着磨损和电气磨损,在水雾条件下主要为电弧侵蚀、塑性变形和轻微的粘着磨损。这是因为水有利于降低摩擦副接触表面的温度,有效地抑制了铜的转移,阻止了粘着磨损的发生。水因素的介入也导致了电弧发生频率的增多,但在综合影响下,水可以有效地改善该试样的磨损性能。