服役损伤对制动盘材料摩擦磨损性能的影响

Influence of service damage on the friction and wear properties of the materials for brake discs

在服役过程中制动盘承受着剧烈的摩擦制动作用,故制动盘材料摩擦磨损性能决定着列车制动性能的优劣。文章分别对带热疲劳裂纹、带热斑和无热损伤的制动盘材料进行摩擦磨损试验。结果表明:无损伤的制动盘材料与闸片有较好的摩擦匹配性,制动盘材料表面形成连续、致密的第三体膜,摩擦因数稳定;热斑损伤会使摩擦副的摩擦因数和磨损率升高,制动盘材料表面第三体膜出现明显剥落;热疲劳裂纹会使摩擦副的平均摩擦因数显著降低和波动,热疲劳裂纹会破坏第三体膜的连续性和均匀性,摩擦过程中形成的磨屑会在裂缝内堆积,使制动盘材料出现增重现象。

As the brake disk withstands drastic frictional braking force in service,its friction and wear resistance decides the brake performance of a train.The paper introduces the friction and wear tests of brake disks with thermal fatigue cracks,hot spots and without thermal damages respectively.Test results show that the undamaged brake disc material matches well with the brake pad,resulting in the formation of a continuous and compact third-body membrane with stable friction coefficient on the surface of the brake disc material;hot spot damage could increase the friction coefficient and wear rate of the friction pair,which in turn would cause an obvious spalling of the third body on the surface of the brake disc material;and the thermal fatigue crack could dramatically reduce and fluctuate the average friction coefficient of the friction pair and break the continuity and uniformity of the third body,while the grindings built-up in cracks during the friction process could increase the weight of the brake disc material.