Simulation Study Of 20/0Cr18Ni9 Dissimilar Metal Welding Based On Simufact Welding

20 steel is usually used in oil,chemical and energy industry as tube material,and OCrl 8Ni9 stainless steel is usually used in the corrosion environment.In order to reduce cost,generally 0Cr18Ni9 is more applied in key place of tube welded joint,and carbon steel is applied in the rest of place in tube,so it is important to join 20 steel and 0Cr18Ni9 stainless steel.At present,the problem in microstructure,corrosion and residual stress more appears in welded joint of 20/0Cr18Ni9.Due to the limitation of experimental equipment and method,the problem in residual stress is less researched,and the systematic research for residual stress and deformation in welded joint of 20/0Cr18Ni9 is not finished.Thus,the study of stress and deformation in welding of 20/0Cr18Ni9 is carried out,which contributes to supplement the research in residual stress and provides theoretical basis for practical application.Based on simufact welding software in this paper,the research is carried out by numerical simulation and practical experiment,a experiment,which is affected by one factor which includes heat input,interpass temperature and environment temperature on welded joint,is designed,and another experiment,which is the effect of orthogonal experiment for the three factors on welded joint,is also designed,in the end,the stress and deformation of weldment of 20/0Crl8Ni9 in thickness of 6 mm is studied.The result of research shows that residual stress and deformation increase with the heat input increase,however,with the interpass temperature increase,residual stress increases but deformation decreases.With the environment temperature increases,residual stress decreases but deformation increases.The result of the stress field in combination of different welding parameters shows that the distribution of stress in every model is approximately same,maximum stress exists in the fusion zone,and the stress in longitudinal direction is apparently more than that in transverse direction.The distribution of minimum stress appears in Case7 model(heat input Q3,interpass temperature 50?,environment temperature 65?).The result of deformation in the orthogonal experiment indicates that the minimum deformation appears in Case3 model(heat input Q2,interpass temperature 250?,environment temperature 65?),but maximum deformation appears in Case9 model(heat input Q3,interpass temperature 250?,environment temperature 20?).In the end,the residual stress and deformation in Case4 model(heat input Q2,interpass temperature 50?,environment temperature 20?)are verified by practical experiment,which shows that the result of simulation is agreement with that of experiment well,verifying model reliability.Based on previous Case4,the heat treatment experiment is studied in this paper,and the effect of orthogonal experiment for heat treatment temperature,holding time and cooling rate on the welded joint is designed.The result of research shows that after heat treatment,residual stress in every heatment model decreases and extremum of stress in every heat treatment model decreases.However,the variation of stress in different zone is different,that is,the reduction range of stress in transverse direction is more than that in longitudinal direction,and the reduction range of stress on 20 steel side is more than that on 0Cr18Ni9 side.The result of deformation of heat treatment shows that the deformation is lesser.In the end,the residual stress in heat treatment model Case4(heat treatment temperature 300?,holding time 30 min,cooling rate 150?/h)is verified by practical experiment,which shows that the result of simulation is agreement with that of experiment well,verifying heat treatment model reliability.The result of orthogonal experiment for welding parameters through significant effect analysis shows that the heat input has a maximal effect on stress and deformation,and it has a significant effect on them.The interpass temperature has the second effect on stress and deformation and has a significant effect on the part of them.The minimal effect on stress and deformation exists in environmental temperature,and there is no a significant effect.The result of orthogonal experiment for heat treatment parameters through significant effect analysis shows that the heat treatment temperature has a maximal effect on stress reduction and deformation and has a significant effect on them.Correspondingly cooling rate has the second effect on them and the minimal effect on them arises in holding time.