Prediction and optimization of tensile strength of 7A52 aluminum alloy friction stir welding joints based on response surface methodology

In order to study the effects of welding speed, stirring head rotation speed and pressure deep of shaft shoulder on tensile strength of 7A52 aluminum alloy friction stir welding. 20 groups of tests were designed by response surface methodology based on central composite test design, and response function relationship were established. In order to verify the accuracy of the response function relationship, variance analysis and regression analysis were used to determine the dominance of the regression model, and the deviation of correlation coefficient R² was only 3.17%. The accuracy of the model was verified by analyzing the influence of single welding parameter and double welding parameter on tensile strength. Finally, the model was verified by tensile test. The results show that the joint tensile strength can be predicated based on response function relationship of response surface methodology fitting, and the best combination of welding parameter (welding speed 110 mm/min, stirring head rotation speed 1 436 r/min, pressure deep of shaft shoulder 0.55 mm) was gained. The maximum predication tensile strength was 380 MPa.