Optimization and ANFIS-based modeling of two step FSSW process parameters on tensile strength for triple-sheet joining of aluminum alloy

In this paper, a potential technique is used to weld three sheets of AA 6082 through a two-step friction stir spot welding (TSFSSW). The optimal settings of the process parameters, namely, the rotational speed of the tool, dwell time, and plunge depth during welding have been analyzed. Taguchi's L9 orthogonal array and ANOVA method is used to get proper material flow, appropriate heat conduction and the stir zone expansion, which helps in preparing sound joint. Microstructural tool analysis and fractography are performed by employing optical microscopy and Scanning Electron Microscopy (SEM). The tool was analyzed before and after use for heat effect along with the observation of the fracture behavior of the joint. To analyze the residual stresses developed in the joint, the XRD analysis is also carried out. The maximum tensile strength of 94.51 MPa was obtained under optimal parameters of the rotational speed of 1200 rpm, dwell time of 10 s, and plunge depth of 2.9 mm. The results of the ANFIS model revealed that a minor difference between experimental and model values (95.62) confirms the validation of the experiment. The resulting experimental findings of the ANFIS model were compared with other similar work done by researchers previously.