Sensitivity Analysis on Friction Stir Welding Process and Tool Parameters for Joining AA6061-T6 Aluminium Alloy Joints

AA6061-T₆ aluminium alloy (AlMgSi alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. The FSW process and tool parameters play a major role in deciding the joint strength. In this paper relationship between the FSW parameters (tool rotational speed, welding speed, axial force, shoulder diameter, pin diameter and tool hardness) and the tensile strength of the joint was established. Statistical tools such as analysis of variance (ANOVA), response surface methodology (RSM) were used to optimize the FSW parameters. A sensitivity analysis is carried out and compared the relative impact of input parameters on tensile strength in order to verify the measurement errors on the values of the uncertainty in estimated parameters.