Experimental Analysis of the Influence of Process Parameters on Residual Stress in AA2024-T3 Friction Stir Welds

Friction stir welding (FSW) is an innovative joining technique, in which a solid state weld is obtained by means of frictional heating and plastic deformation of the processing material. In recent years, an increasing application of the FSW process has been observed, however, for the effective implementation of the technique in safety-critical components and to predict the fatigue behavior of FSWed assemblies, an accurate knowledge of the process-induced residual stress is needed. In this paper results, provided by an experimental analysis on the influence of process parameters on the residual stress in 4mm AA2024-T3 butt joints are reported and discussed. The contour method has been applied to evaluate the residual stress. An asymmetric stress distribution has been found in all samples. A significant dependence of the tensile and compressive stress peaks on the feed rate has been found, while a non monotonic influence of the rotating speed has been evidenced.