Simulation Of Residual Stress And Deformation Of Multi-pass Welding Of Tube Sheet Based On SYSWELD And Its Process Optimization

The instantaneous high temperature during the welding process causes welding residual stress and welding deformation in the welded parts after welding.The value is relatively large,which affects the stability of the welded parts.In severe cases,it will also cause cracks,which will damage the welded parts and affect the entire structure.This paper takes the tube-plate structure as the research object,uses the thermo-elastoplastic finite element method to simulate,obtains the distribution of welding residual stress and deformation,and selects the best welding process through comparative analysis.The main research work is as follows:(1)Use SYSWELD finite element software to simulate the tube sheet welding process,and obtain the temperature change during the welding process,the phase change distribution after the welding part is cooled,the welding residual stress and the peak size of the welding deformation,and Distribution.(2)Six different welding sequence schemes are used,and simulation is performed under other conditions unchanged,and the distribution of the stress field and deformation field after welding is obtained.By comparing the residual stress,the overall peak value of the deformation and the points on the extraction path to obtain a set of welding sequence schemes with the smallest residual stress and deformation.(3)On the basis of all conditions being the same,change the groove angle to explore the influence of different groove angles on the welding residual stress,the peak value and distribution of welding deformation,and select a set of groove plans with the smallest residual stress and deformation.(4)Select a more complex multi-layer multi-pass welded tube sheet structure for simulation,and explore the residual stress,the peak value and distribution of welding deformation after welding of the same metal and dissimilar metal by changing the welding materials,and obtain a set of It is more suitable for welding materials required by industrial use.The simulation results show that:(1)After the weld is cooled,the metal phase is composed of bainite and martensite;the peak of the welding residual stress appears on the weld,and the welding deformation mainly appears near the weld and the edge of the plate,and its peak is at the weld on.(2)Through the comparison of six different welding sequence schemes,the overall and partial equivalent residual stress,transverse residual tensile stress,longitudinal residual compressive stress and residual deformation values of the alternate upper and lower welding sequence adopted in the second scheme are all six schemes.The minimum value among the two;especially in terms of equivalent residual stress,transverse tensile residual stress and longitudinal deformation,the welding sequence used in the second program is much smaller than other programs,so the welding sequence of the second program is better than other programs.(3)By comparing three different bevel angles,50° bevels are smaller than 40°,45° bevels in terms of equivalent residual stress,transverse residual stress,longitudinal residual stress,overall deformation,and transverse deformation.The difference between tensile residual stress and longitudinal compressive residual stress is large,so 50° bevel is the best bevel.(4)The value of residual stress,peak value of deformation and extraction path of dissimilar metal welding is smaller than that of the same metal welding,especially in the transverse and longitudinal tensile residual stress,the difference is large,so the dissimilar metal welding method is superior for welding of the same metal.Through simulation,it can be found that the influence of different welding processes on welding quality is very important.The best welding method and welding conditions can be determined through simulation before welding starts.