Study on deformation and residual stress of laser welding 316L T-joint using 3D/shell finite element analysis and experiment verification.

In this paper, T-joint of 316L steel is obtained by subsection laser welding method without jig, while a thermal elastic-plastic finite element model considering multi-linear yield stress curves and multi-point constraint equations is developed to estimate welding deformation and residual stress. A simplified heat source model with the actual bead geometry is proposed to reduce the number of finite element meshes. Prediction errors between the simulation and experimental measurement results of angular distortions of three reference lines are −11.0, 0.9, and 7.9 % respectively, and the maximum residual stress is 396 MPa. Meanwhile by microstructure analysis, austenite and ferrite are consisted in weld, segregation and dendritic structures are also observed, while the heat-affected zone is very narrow. In a word, weld line with large travel can be welded by subsection laser welding method without jig, while the finite element method proposed in this paper is effective to predict welding deformation and residual stress. [ABSTRACT FROM AUTHOR]