Effect Of Temperature On Wear Of Railway Overhead Line-pantograph System Under Electrical Current

Railway transportation is one of the most important transportation ways in our country. Nowadays, Chinese railway transportation is characterized by high speed, heavy haul, and long mileage. The railway overhead line-pantograph system is one of the most important components of the electrical locomotive, which is the only way to provide power for the electrical locomotive effectively. As to the railway overhead line-pantograph system, the efficiency of power transmitting and the service life of the pantograph strips directly affect the traction capability of the electrified trains. The main factors affecting the wear failure of the railway overhead line-pantograph system are temperature, electric current, and humidity. Among them, temperature is too important to be neglected. Temperature can change the micro-topography of the contact surface and the friction coefficient of the friction system. So it is important and practically significant to study the influence of temperature on the wear failure of the railway overhead line-pantograph system.In this dissertation, a series of tests were carried out to study the friction and wear behavior of railway overhead line-pantograph system using a pin-on-disc tester. In the tests, all specimens came from an actual railway overhead line-pantograph system. The pin test piece was made of carbon, which came from a in-using pantograph strip.The disc was made of pure copper. A date acquisition system was used to record the friction coefficient, rotation speed and electrical current. SEM observations of the worn scars were performed to analyse the micro-topography of worn scars and the surface components of the wron scars were detected by EDS. The influence of temperature on the friction coefficient, wear volume, surface topography of worn scars and components of the contact surfaces was studied in detail. Through the work in this dissertation, several main conclusions can be drawn as follows:1. Temperature has an effect on the friction coefficient of the railway overhead line-pantograph system. Generally, the higher the temperature, the lower the friction coefficient is.2. Temperature has a large influence on the wear volume in railway overhead line-pantograph system. When the temperature is low, the abrasive wear plays the main role and the wear volume is light. When the temperature is high (more than 200℃), adhesive wear plays the main role and the wear volume becomes large.3. Temperature also has influence on the surface topography of the railway overhead line-pantograph system. High temperature will melt some materials of the carbon strip and form oxidiation and melting layers.4. Temperature is a main factor affecting the wear volume of the railway overhead line-pantograph system. When the temperature is below 160℃, there is only a slight difference between the wear volume without electric current and that with electric current.