Effect of Surface Temperature of Carbon Strip on Its Wear Mechanisms in the Pantograph–Catenary System Under High-Speed and Heavy Current Loading

Abstract

Abstract. As a critical component for transmitting electrical energy in pantograph–catenary systems of high-speed railways, carbon strips operate under high-speed and heavy-current conditions, where elevated surface temperature directly governs the wear mechanisms and operational safety of carbon strips. Therefore, investigating the surface temperature and wear mechanisms of carbon strips in the pantograph–catenary system is critical. This study quantitatively investigates the effects of loading current (70–150 A), normal load (90–110 N), and sliding speed (200–300 km/h) on the surface temperature, wear-rate, and friction coefficient of carbon strips sliding against copper contact wires, using a ring-block type high-speed wear tester. Surface morphology and elemental composition are characterized by scanning electron microscopy and energy-dispersive spectroscopy. Results indicate that the sliding speed has the most pronounced effect on surface temperature. A fundamental transition in the wear mechanism is identified at a critical threshold of 521 °C. Beyond this point, a severe molten-material ejection phenomenon occurs due to the abrupt change in arc force on the contact surface of the carbon strip. This phenomenon leads to splattering of surface material accompanied by direct material loss. It generates a substantial amount of cupric oxide particulate matter, markedly diminishing the carbon content on the strip surface while inducing a sharp nonlinear increase in the wear-rate. Therefore, controlling the interfacial temperature to suppress molten-material ejection is crucial for mitigating severe wear and ensuring the operational reliability of the carbon strip under extreme conditions.