Numerical Analysis of Welding Deformation in Double T-Joints of 304 Stainless Steel Sheet

Abstract Thin plate welding is very prone to instability and deformation, which has a strong impact on the functional realization and service life of components. Employing the thermal-elastic-plastic finite element method, the welding deformation of double T-joints of 304 stainless steel sheets with a thickness of 1.5 mm was simulated. Initially, employing the abaqus platform and integrating a subroutine developed in fortran, the heat source allocation and application were simulated. Utilizing a dual ellipsoidal heat source model, the welding process was simulated by the thermal-elastic-plastic sequential coupling approach, and six distinct welding sequence schemes were evaluated via simulation. Scheme 2 has the minimal equivalent deformation, being designated as the optimal welding sequence. Subsequently, the welding deformations of the nine cases in scheme 2 were analyzed by changing the welding current (100 A, 120 A, and 150 A) and welding speed (10 mm/s, 12 mm/s, and 15 mm/s). The experimental results demonstrated that case C exhibited the optimal welding performance, characterized by a maximum equivalent deformation of 19.65 mm at welding current equals 150 A and welding speed is 10 mm/s. When the welding speed was fixed, a higher welding current resulted in diminished welding deformation at each node; and when the welding current was constant, the welding speed had a negligible effect on the deformation. Besides, the trend of residual stresses was distributed symmetrically, the value of longitudinal residual stresses was much larger than the value of transverse residual stresses, and the changes in welding speed and welding current had less influence on the longitudinal residual stresses.