Optimization of FSW process parameters for 2219-T8 aluminum alloy thick plate with residual stress

Abstract

The selection of welding process parameters during friction stir welding (FSW) process of 2219 aluminum alloy thick plate directly affects the strength and distribution uniformity of residual stress after cooling and solidification of the weld seam. When the selection of process parameters is improper, it can generate significant residual stress and cause distribution imbalance. When combined with external stress, it can reduce the rigidity and dimensional stability of the structure, and even lead to component fracture. In solve to this issue, A finite element simulation on the residual stress of FSW joints in 2219 aluminum alloy thick plates is established. The simulation experiment is designed using response surface methodology to study the influence of spindle speed, welding speed, and pressing amount on longitudinal peak residual stress, and prediction model is established. The model is evaluated through analysis of variance and regression analysis. The results showed that spindle speed was the most significant factor (contributing 92.43%), far higher than welding speed (4.47%) and pressing amount (1.05%). The coefficient of determination (R²) of the regression model is 0.9981, the adjusted R² is 0.9946, and the predicted R² is 0.9759, confirming the excellent goodness of fit and reliability of the model. Finally, with the goal of minimizing longitudinal peak residual stress, the optimal process parameter combination is determined by genetic algorithm: spindle speed of 400 rpm, welding speed of 75 mm/min, and pressing amount of 0.09 mm. This study provides a basis for the optimization of FSW process parameters for 2219 aluminum alloy thick plates, and provides methodological references for the optimization of process parameters in other engineering manufacturing processes.