Experimental Study On The Current-Receiving Quality Of A Contact Network System And The Wear Behavior Of Copper-Impregnated Metallized Carbon With Electric Current

With China's urbanization, more and more attention is paid to an electrified railroad owing to its predominance in environmental protection, energy saving, economy, safety and so on. The contact network system is one of the three difficult problems for an electrified railroad. Therefore, the study on current-receiving quality of contact network systems and wear behavior with electric current is of significance in economic benefits and in development of railway transportations.A series of tests on the current-receiving quality of a contact network system and the wear behavior of stainless steel 316/copper-impregnated metallized carbon with electric current were studied on a high speed pin-on-disc friction and wear tester. The factors affecting the current-receiving quality of the contact network system were analyzed based on the voltage signals collected by a dynamic data acquisition system. The wear mass loss of pin specimens was weighted by a precise electronic balance. Worn morphology of the specimens was observed by means of Optical Microscopy (OM), Laser Confocal Scanning Microscopy (LCSM) and SEM. The effects of initial current, contact force, stiffness, the polarity of pin specimens, sliding speed, etc on wear behavior were studied. The results were as fololows:1. The current-receiving quality of a contact network system keeps stable at low speed and it would become bad with an increase in speed. Furthermore, vibration characteristics of the contact network system and surface characteristics of sliding friction pairs also affect the performance of the current-receiving quality.2. In the test parameters, the larger the contact normal force, the better the current-receiving quality becomes and the higher the sliding speed corresponding to good current-receiving quality. The current-receiving quality when the pin specimens are supported by spring elements becomes better than that without spring supports.3. For a stainless steel 316/copper-impregnated metallized carbon couple, the wear rate of pin specimens without electric current exhibits a monotone increase with increasing speed. The wear mechanism is mainly attributed to adhesion and abrasion. The wear rate of pin specimens without electric current shows a monotone increase with an increase in electric current. The wear mechanism is mainly attributed to adhesion and abrasion, oxidation and electric arc ablation loss. The local area of the disc specimen was melted.4. The wear of pin specimens with electrical current includes mechanical wear and electrical wear. To some degree, the wear rate of pin specimens is related with the current-receiving quality. In the test parameters, there is a maximum value in the wear rate of pin specimens with the variation of sliding speed.5. Under electrical current, the wear rate of the pin specimen as cathode is different from that as anode. Severe arc discharge and severe spark can be observed on pin specimens as cathode, whilst severe arc discharge and a little spark can be observed on pin specimens as anode. Furthermore, the wear rate of pin specimen as cathode is higher than that as anode.