Research On Residual Stress Regulation Technology Of Typical Welded Joint Of Locomotive Bogie Frame

This paper focuses on the study of the residual stress of typical welded joint,taking the locomotive bogie frame as the engineering application background.The bogie frame is a welded structure,which is the key bearing and force transmission component of rolling stock,so its welding quality is very important to the safe running of trains.Residual stress is inevitable in welding process,which may reduce the bearing capacity of the frame and affect its fatigue life.The research on the regulation technology of the residual stress of welded joints can effectively reduce the peak value of the residual stress and improve the welding quality of welded joints,which has important engineering application value for improving the bearing capacity and service safety of the frame.In order to quickly establish a heat source model that is more in line with the actual molten pool contour,this paper uses the difference image method and the image processing technology of pseudo-color enhancement to solve the molten pool shape parameters of the heat source model.Through the comparison of the molten pool contour shapes of the double ellipsoid heat source model,that is,the comparison between the molten pool contour shape resulted by simulated calculation with Visual-Environment software and the actual molten pool contour shape,the quantitative error of the coincidence degree of the two molten pool contour shapes is obtained.By modifying the double ellipsoid heat source model parameters and reducing the error value,the double ellipsoid heat source model parameters that can simulate the actual molten pool contour shape is finally obtained.The minimum error of the simulated and tested molten pool contour shape is 14%.Considering the obvious effect of welding process parameters on residual stress,the process parameters of voltage,current and velocity are combined to carry out the finite element simulation calculation of the welding T-joints based on the Visual Environment simulation software.By means of model verification to welding T-joints molten pool contour,and comparison and analysis to the stress distribution and stress curve,the relationship between parameters and stress is resulted,and the process method of reducing stress is put forward.For the multi-layer and multi-pass welding,the residual stress distribution rule of butt-weld joints multi-layer and multi-pass welding is studied by means of thecombination of welding test and simulation analysis,and model verification is carried out to the butt-weld joint molten pool contour.Through the study of the different weld pass number in the same layer in multi-layer and multi-pass welding,the method of regulating residual stress is put forward,and the conclusion that the appropriate increase of weld pass number is beneficial to reduce residual stress is drawn;the results show that,within the scope of the welding test study parameters,the similarity of welding parameters of each layer is more beneficial in reducing the welding residual stress.Considering the effect of welding speed on the regulation of residual stress in multi-pass welding,on the basis of the study of multi-layer and multi-pass welding,the cosmetic welding process design principle for regulating the residual stress is put forward,the butt plate three-layer and six-pass welding test is established,and the simulation analysis is carried out.Based on the fixed parameters of welding voltage and current,the simulation study on four different welding speeds of three-pass cosmetic welding is carried out,and the welding stress distribution and stress curve are analyzed.The results show that the more similar the welding speed of three-pass cosmetic welding is,the smaller the residual stress is.51 figures,5 tables,45 references.