Elastic pre-compensation for welding-induced shrinkage and bending deformations of thick plates by friction stir welding

Shrinkage and bending deformations are difficult to be controlled for large thick plates joined by friction stir welding (FSW). In this paper, a new elastic pre-compensation method is proposed to reduce the shrinkage and bending deformations simultaneously. The analytical model of welding-induced inherent strain with elastic pre-deformations is established, by which the correlation of elastic pre-deformations and the welding inherent strain is revealed. The optimal parameters for the elastic pre-deformations are determined by using the Newton–Raphson algorithm. The experiment for AA2024-T351 thick plates is conducted, in which the welding deformations of thick plates are effectively mitigated by using the optimal elastic pre-deformations. The proposed method may be useful for the process control of FSW for large thick structures.