A Study On Temperature Field And Residual Stress Of Some High-way Rail Motor Base Under Laser Cladding

In recent years, the rapid development of high-speed rail service in our country,which reached the first-class level in the world. But there still existed some hiddendangers. In order to improve the safety of high-speed rail, the relevant departments ofour country proposed recently a higher standard about production and manufacturingof high-speed railway. According to the new standard, the thickness of the motor baseof the high-speed trains is required to increase.Laser cladding is a complex process including heat transfer, convection,metallurgy and mechanics. It involves many aspects such as transformation fo thelaser energy into heat, heat transfer and convection in the melt pool and phase change,melting and solidification of the alloy powder and base metal, thermal stress anddeformation. Through numerical simulation of laser cladding, the best cladding path,the optimum cladding parameters and optimum cladding materials can be determined.ANSYS is a powerful software for finite element analysis, which is good atdealing with the latent heat of phase change. The contents of this paper are as follows:1)The finite element model to the motor base is established. Then，the softwareANSYS is used to solve the above model. By setting the material parameters, thecladding path and boundary conditions, the temperature field of laser cladding processis calculated, from which the process of temperature change during laser cladding andthe steady state temperature distribution can be analyzed, and the maximumtemperature and its distribution profile can be determined.2)Based on the temperature field，by using the’’order’’ coupling method tochange the type of elements, the stress field in laser cladding process and coolingprocess can be obtained. Through the stress nephogram, the stress changes in theheating and cooling process can be analyzed, and the maximum stress and residualstress after sufficient cooling can be determined.3)Based on the above stress field，the deformation of the motor base during lasercladding is investigated. After comparing the deformations of the motor base underdifferent cladding paths and colling boundary conditions, the optimal cladding routeis determined.4)Experiments of laser cladding are carried out. After laser cladding, thedeformations of the samples under different cladding conditions are measured, which are in some extent in good agreement with the above simulation results. Finally, themicrostructure of the laser cladding layers is analyzed by means of metallography.