Multi objective optimization in friction stir welding using Taguchi orthogonal array and grey relational analysis

Friction stir welding (FSW) is a recent and effective solid state joining technique for joining similar and dissimilar metals. In this communication FSW is carried out on mating pieces made of aluminum alloys AA5083 and AA6061 having dimensions of 65×60×6 mm. An attempt has been made to optimize the process parameters of FSW for Hardness and Toughness of weld bead using Taguchi Technique and grey relation analysis (GRA). In this study, 3 parameters: rotational speed, tool transverse speed and tool depth are considered with 3 levels. Consequently L9 orthogonal array is constructed and 9 experiments are performed to employ aforementioned optimization technique. Taguchi technique and GRA is analyzed in MINITAB software to find out the optimum value of process parameters and observe their contribution. From this study is found that contribution of rotation speed is higher for hardness and contribution of plunge depth is higher for toughness.