Influence of the clamps configuration on residual stresses field in friction stir welding process

Friction stir welding is a joining process developed in 1991 by The Welding Institute. This welding technique is a solid-state joining process leading to joints with good mechanical performance and low residual stresses. In all welding techniques, the clamping systems have an important role in determining the quality of the welds and mechanical characteristics. Even more in friction stir welding, the position of the clamps plays a critical role because it is mainly a mechanical process with high forces involved. In this article, the correlation between the residual stress field and configurations of clamps has been established numerically. For this purpose an uncoupled thermo-mechanical finite element analysis has been carried out. The mechanical loads due to the tool have been also implemented into the model. The thermal and mechanical models have been validated on temperature field recorded by an infrared camera and residual stress field measured by X-ray diffraction analysis. The friction stir welding test was conducted on 6-mm-thick 5754 H111 aluminium alloy plates.