Study On The Residual Stress And Deformation Of Circumferential Welding Of Thin Plate And Boss Parts Using Electron Beam Welded

In this paper,GH4169 alloy thin plate and boss are welded by vacuum electron beam welding.The effects of welding heat input and plate thickness on welding deformation of specimens are studied.Through different heat treatment tests,the influence of heat treatment process parameters on welding stress is studied,which provide the suitable heat treatment process parameters for eliminating the stress of weldment and provide the practical basis.The results show that:the boss weldment produce in-plane deformation.The deformation along the edge of the welded plate is large in the middle and small on both sides;the degree of the intermediate concave increase with the heat input increasing.The amount of shrinkage deformation is proportional to the heat input and inversely proportional to the thickness of the plate.Using thin plate with 2mm thickness to weld a single boss part,when the welding heat input is increased from 54J·mm^-1 to 84J·mm^-1,the shrinkage deformation is increased from 0.20mm to 0.48mm;and when heat input and thickness are 54J·mm^-1 and 2 mm,respectively,the shrinkage deformation is 0.20mm.And when the thickness is 5 mm,there is almost no deformation.The in-plane deformation of weldment with double boss is greater than that with single boss.The thin plate and the boss weldment produce a convex-concave deformation or a concave-convex type instability deformation,which is characterized by that the edge of the weldment is irregularly upturned and downturned around the annular weld.The out-of-plane deformation of the welded single boss weldment is caused by the shrinkage deformation.Due to the difference in the distance between the weld and the edge of the plate,the amount of shrinkage deformation is different,resulting in an asymmetry in the amount of upward warping.It performs alternate change from upwarp to downwarp.When the plate thickness is constant,the welding heat input is larger,and the amount of deformation of the upwarp and downwarp is larger.The thinner the plate and the greater the heat input,the larger the deformation of the upwarp and downwarp The out-of-plane deformation caused by the thin plate and the double boss weldment is more complicated than that of the welded single boss weldment.The out-of-plane deformation consists of angular deformation,deflection distortion and wave-like deformation.They are caused by the distance between the ring welds of the welded double bosses is different from the edge of the plate,the shrinkage deformation,angular deformation,deflection distortion and wave-like deformation of different parts of the plate are different,resulting in alternating changed of the convex and concave parts of the weldment.When the plate thickness is 2 mm and the input is 54 J·mm^-1,the maximum upturn deformation of the thin plate is 3.60 mm,and the maximum lower warping deformation is 3.90 mm.When the heat treatment temperature is 750°C and the holding time is 10 h,the average total stress on the center line weld in the longitudinal direction of the plate after heat treatment is 84.1%lower than that of the welded test piece.The average total stress on the centerline weld of the plate width direction is reduced by 80.5%.Under the condition of heat treatment temperature of 800°C and holding time of 8 h,the average total stress on the centerline weld of the plate length direction is reduced by 87.9%compared with the weldment,and the average total stress on the centerline weld of the plate width direction is reduced by 86.0%.Therefore,the welding stress elimination effect is more obvious as the post-weld heat treatment temperature and the holding time increase.