Effect of elastic pre-bending on mitigating welding deformation for aluminium alloy thick-walled plates joined by FSW

Welding-induced deformation affects the dimensional accuracy of welded components. The mitigation of welding deformation is important for the quality control of welded structures. In this paper, the mechanism of welding angular deformation for thick-walled plates joined by friction stir welding is clarified based on the inherent strain method. The transverse elastic pre-bending method is applied to mitigate the welding-induced angular deformation. An analytical model is developed to quantitatively study the effect of transverse elastic pre-bending displacement on the welding angular deformation. The optimal pre-bending displacement is determined to be 1.37 mm based on the quantitative model, by which the welding angular deformation is reduced to 0.02 mm. The influence of welding process parameters on the optimal pre-bending displacement is discussed, which may provide the guidance for the deformation control of welded structures.