The effect of laser segmented skip welding on welding distortion and residual stress in butt weld of 6061 aluminum alloy thin plate

In the present work, welding heat distribution state and its influence on welding deformation were investigated by adjusting the laser welding sequence, and then the thin plate welding parameters were optimized. Numerical simulation and experiment were used to investigate the welding deformation of laser welding 1-mm 6061 aluminum alloy thin plate. Numerical simulation was performed using Abaqus and Fortran for sequential coupled temperature-displacement analysis and experimental validation. The numerical simulation was used to quantitatively compare the welding deformation and residual stress caused by single-weld continuous welding and single-weld segmented skip welding. Results show that the transverse shrinkage of the single-weld segmented skip welding was smaller, the longitudinal shrinkage control was better, and the out-of-plane deformation was lower than those in single-weld continuous welding. Compared with single-weld continuous welding, the transverse shrinkage of segmented skip welding decreased by 7.14%, the average longitudinal shrinkage decreased by 34%, and the deflection deformation decreases by 12.9%. The adjustment of thermal distribution improved the generation and release of residual stress. The peak stress value at location 3 was reduced by 12% for segmented skip welding. For longitudinal residual stress, the high stress zone appeared in the weld center of segmented skip welding, but the average longitudinal residual stress decreased by 7.8% from 237.4 to 218.7 MPa.