Experimental research on the mechanism of the delamination extension of the carbon strip with heavy electrical current at the speed of 360 km/h

Delamination wear leads to a surge in the wear loss of the carbon strip. It also has a significant influence on the physicochemical properties of the contact pairs in the pantograph-catenary system (over 250 km/h). In this paper, the pure carbon/copper-alloy friction pair was chosen as the research object to study the wear evolution mechanisms and the law of delamination wear extension of the carbon strip, using a ring-on -block wear tester with a design speed of 400 km/h. And the arc discharge energy was calculated to investigate the quantitative relationship between the delamination wear and the arc discharge in the process of the test. The experimental results show that the frictional coefficient increases gradually with the experiment. The frictional coefficient with electric current is much bigger than that without electric current under the same test conditions. Under the intense arcing (when the average single arc discharge energy e > 76J), the delamination wear initially appears on one edge of the strip and gradually extends to the middle of the strip when sliding time t exceeds a certain value, which results in the increase of the wear of the strip and the further enhancement of the arc discharge. The result also indicates that delamination wear and its extension are occurred by the cumulative effect of the heat caused by the long-time strong arc discharge.