Research Of The Temperature Characteristic Of Rail Gas Pressure Welding Base On Constant Displacement Control

CWR track (Continuous welded rail track) is an important symbol of rail structure technological progress, in order to further improve train safety, comfort and speed, it needs to improve the quality of rail welding joint.The welding temperature is the most important factors to quality of rail welding joint, the research of temperature field of GPW (gas pressure welding) has great significance.In the heating process of GPW, the thermal stress of rail joints generated by the thermal expansion, remove the influence of the external environment, and only by the influence of temperature field, so the thermal stress and the temperature field, there are certain physical relationship. This paper bases on constant displacement control technology of GPW,statistics and analysis the collected data of rail joints in different elevations,collects the corresponding relationship between holding pressure and time, indirect analysis the corresponding relationship between equivalent temperature and time,Analyzing the change rule of data in different altitudes.Using ANSYS simulate software, and carry out the simulated research of rail welding joints’ temperature field, simulating the temperature field distribution of rail joint and drawing the equivalent temperature---time curve of different parts in welding face. The simulated results and actual collection results are compared, analysis the identical situation. To explore a new method of indirect measurement and valuation of welding temperature field characteristics, improve the rail welding technology and equipment level,reduce welding costs, improve and perfect the welding process of GPW constant displacement, is of great significance.Results show that the constant displacement quality control method of GPW, the process of welding heating with temperature rising, rail expands, pressure sensors collect the change rule of holding pressure which present first increases then decreases,No matter the altitudes, its holding pressure change rules are consistent good. Through pressure sensor of GPW machine collect the relationship of the pressure and time, the method which using the relationship of the pressure and time monitor equivalent temperature field is feasible and practical; This paper use ANSYS simulate temperature field characteristics of GPW, the identical degree of simulated results and the practical results is great,the quality of welding joints by GPW constant displacement control are wonderful.