Research Of New Technology&New Equipment Of Thermit Welding

With the rapid development of railway modernization, especially the jointless track and the transportation technology high speed and heavy haul railway, the rail welding technology is playing a much more important role in railway construction project of China. The thermit welding is a main welding method of rail joint in the technologies on site of rail joint the jointless track, which is widely used in the rail laying of jointless track, turnout junction and the repairing welding of broken rails.However, many influence factors exist in the quality of welding joint, and there is a big gap in the quality of rail welding methods between flash welding and gas pressure welding, which also has a problem of the high end-breaking rate of joints. So it will have important meaning for promoting the qualities of thermit welding, especially by improving tissue properties brought by this welding technique fundamentally.In this paper, the welding temperature field numerical simulation of thermite welding of rails and small samples based on ANSYS Workbench is studied, which builds a theoretical basis for the research of the rail thermite welding, and provides a theoretical basis for experimental methods of thermite welding of small samples. Four examples of devices are designed out for the experiment of pressure thermite welding of small samples that are used to study with the orthogonal experiment designing method, from which we get lots of test results of microstructure and hardness tests under different schemes. And the pressing welding machine of mechanism electronics and hydraulic is designed preliminarily.The results show that the research results of the welding temperature field numerical simulation of thermite welding of rails and small samples based on ANSYS Workbench is well consistent with the actual experimental ones. In the results, the relative errors between them are all less than6.6%.Through the experimental study on the pressing thermite welding of small samples, the law of the optimum process of the pressing thermite welding of rails if found that a better quality joint of pressing thermite welding can be got when the upset length is nearly double the pre-welding gap. The equipment of pressing thermite welding of rails that include the systems of machinery, hydraulic pressure and PLC is designed with three-dimensional simulation and PLC software, which does have some practical value.