Effect of welding sequence on residual stress and deformation of 6061-T6 aluminium alloy automobile component
(1. State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University, Changsha 410082, China;
2. School of Mechanical Engineering, Hunan Industry Polytechnic, Changsha 410208, China;
3. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China)
2. School of Mechanical Engineering, Hunan Industry Polytechnic, Changsha 410208, China;
3. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China)
Abstract: Four different welding sequences of double-pulse MIG welding were conducted for 6061-T6 aluminum alloy automobile bumpers by using nonlinear elastoplasticity finite element method based on ABAQUS software. The post-welding residual stress and deformation were definitely different among the four welding sequences. The results showed that the highest temperature in Solution A was approximately 200 °C higher than the melting point of base metal. High residual stress was resulted from this large temperature gradient and mainly concentrated on the welding vicinity between beam and crash box. The welding deformation primarily occurred in both of the contraction of two-ends of the beam and the self-contraction of crash box. Compared with other welding sequences, the residual stress in Solution A was the smallest, whereas the welding deformation was the largest. However, the optimal sequence was Solution B because of the effective reduction of residual stress and good assembly requirements.
Key words: double-pulse MIG welding; welding sequence; welding residual stress; welding deformation; optimal solution