Simulation Research Of Welding Residual Stress And Deformation For Aluminum Alloy

With the sustained and healthy development of high-speed railway in our country,the quality of welding is paid more and more attention.In the process of welding,the existence of welding residual stress and deformation is one of the most important problems.The welding residual stress will affect the safety of train operation,and the residual deformation will affect the assembly accuracy of the train,so it is necessary to study the formation and distribution of welding residual stress and deformation as well as the influencing factors.The finite element simulation analysis provides an simple and effective analysis method for welding residual stress and deformation,greatly save time and cost,and now this method has played an increasingly important role for residual stress and deformation.In this paper,5083 aluminum alloy and its matching 5183 wire are widely used by aluminum alloy high-speed train body.Taking the welding process of its Semi-automatic argon arc welding as research object,the thermophysical properties parameters of two materials are obtained firstly,then the simulation analysis method is preliminary explored by finite element analysis software,and then the influence of heat source shape on welding residual stress and deformation is analyzed.By analyzing each welding temperature field and stress and strain field,the main conclusions are concluded below four aspects:(1)Through the temperature cycle curve of five nodes selected in the longitudinal direction of the weld and three nodes selected in the central width direction,the welding temperature field well reflects the welding heat cycle process,the weld is completely melted,in line with welding practice.(2)The residual yield stress has a certain safety margin with the material yield strength under the von Mises strength criterion.The longitudinal residual stress mainly concentrated in the weld and heat affected zone,in the transverse direction,the maximum value appears in the heat affected zone,in the longitudinal direction of both ends of the stress value is small,the stress level of the middle is high.The transverse residual stress is first increased and then decreased in the transverse direction,the maximum value appears in the heat affected zone,in the longitudinal direction both ends are compressive stress,and the stress is much larger than tensile stress of the central,roughly trapezoidal distribution.Generally speaking,the stress level of the longitudinal residual stress is higher than that of the transverse residual stress,which occupies a dominant position.(3)The residual deformation is basically shrinkage deformation.The longitudinal deformation is mainly concentrated in the weld and heat affected zone,the welding seam is the largest,and it has been increasing in the direction of the weld.The transverse deformation is the smallest at the weld seam,and it increases slightly after the heat affected zone.The angular deformation is approximately saddle shaped.(4)Changing the shape parameters of ellipsoid heat source has little effect on the residual stress and has a certain influence on welding residual deformation,the longitudinal deformation and transverse deformation and angle deformation will increase with the increasing in width and the decreasing in depth of the heat source.During numerical simulation and production,the influence of heat source shape parameters on residual deformation should be paid attention to.