Friction stir welding is a solid-state joining process. This process is an ideal method for joining dissimilar metals. Thermal history directly affects the final properties of dissimilar FSW. Finite element (FE) simulation of heat transfer and residual stresses of dissimilar joins was performed by a decoupled thermal and mechanical analysis. The purpose was to investigate the effect of rotational speed on heat distribution and residual stresses during welding. To calibrate the model, steel and aluminum were joined by FSW at two different rotation speeds. The thicknesses of aluminum (AA6061) and steel (st37) were 5 mm and 2 mm, respectively. The temperature during FSW was measured and recorded at 3 different points by K-type thermocouples. XRD method was used to measure the residual stress. The FE model was calibrated with these experiments by a good approximation. The calibrated model then was used to predict the thermal history as well as the residual stress at other rotation speeds. This procedure offered a cost-effective and reliable method to predict the thermal history and residual stress during FSW of dissimilar metals.
