Optimization of process parameters of friction stir welding using desirability function analysis

Abstract

The latest generation of Aluminum–Lithium alloy (Al–Li) is majorly used in aerospace industries due to its low density and high strength. Friction stir welding is a preferred joining method for the joining of Al–Li alloy due to its low heat input. The quality of the weld is majorly influenced by the process parameters. In the present work, FSW is conducted on Al-Li based alloy AA2099 T8 and studied the effect of process parameters. The objective of this article is to optimize the process parameters for maximizing the tensile strength at a minimum tool wear rate. The process parameters are optimized by the composite desirability analysis coupled with Taguchi L16 orthogonal array. The rotational speed, welding speed, tool profile, and welding condition are considered as the input process parameters. Mathematical models are developed for tensile strength, tool wear rate, and composite desirability, and the accuracy of the model is found at 95.94, 91.04, and 98.23%, respectively. Furthermore, it is observed that the improvement in composite desirability is 11.01% at optimum parameters. Moreover, the improvement in tensile strength and wear rate of the tool at optimum parameter (rotational speed 1500 rpm, welding speed 90 mm/min, tool profile cylindrical, and welding condition 80 preheated) was observed at 5.32 and 1.65%, respectively.