Research On The Design Analysis Technology Of Falsh Welding Machine For Locked Rail

CWR(Continuous welded railway)is a great progress of 20th century railway track structure, its many advantages make it the optimal choice of the high-speed, heavy-loading track, and it is quite favored by all the world. The technology of rail welding plays an important role in the engineering of laying CWR, which determines the quality of rail tie-in directly, then affects traffic security. Therefore, research on the key technology of the rail welding and optimization of welding parameters are significant to improve the quality of rail welding.The flash welding is the main method in rail welding now. Because welding involves in electromagnetism, heat transferring, metal melting and freezing, phase-change, welding stress and deformation and so on, so it is a complicate physicochemical process. With ANSYS, an useful general software in the finite elements analysis field, this paper accomplishes the dynamic simulation of rail welding temperature field and stress field. First the paper analyzes the temperature field in the flashing stage and how residual stress of different directions are in the upsetting stage, then describe the deformation of the rail in the cooling period. Second the paper analyzes the design of the head device of flash welding machine and deformation of the check part. At the same time, the calculation result accords with the experiments in the study, which indicates that the model used in the simulation is correct. The paper can provide important reference for the design of flashing welding machine for rail and choose the right material, and assist engineers to make sure some key parameters in the welding process , all these make the design of welding machine based from the experience to the scientific experiments.For the simulation of the temperature field, the paper establish the symmetry model and simulate material loss during the period of flash by using the element-birth&death technique, giving out an idea that how to simulate the process of thermal-electrical coupling. At last, the paper provides the real temperature field which is taken by using infrared camera, and the comparisons indicate that the simulation result can reflect the real one well. Basis on the fact, the paper studies the influence on temperature distribution by different extension length.Although welding temperature field and stress strain field are bi-directional couple, because stress and strain field have little influence on the temperature field, this paper only consider the single couple which temperature field effect on stress and strain field .when calculating, though the ANSYS's thermal-structure couple function, firstly calculate welding temperature field and save the result, then use the temperature result as load to calculate welding stress and deformation.Founded on the simulation of the temperature field, the paper analyzes the stress and strain in the upsetting deformation stage by using the thermal-force couple function and determines the appropriate predistance at the maximum upset distance and the shortest upset time, all these will assist the design of the hydraulic pressure system in the whole flash welding machine.