Optimization of Friction Stir Processing Parameters for 60/40 Brass using Taguchi Method

Abstract

Friction stir processing derived from friction stir welding is a severe plastic deformation technique. Friction stir welding is a solid state metal joining technique developed at TWI (the welding institute) U.K. Friction stir processing has applications into a broad fields covering superplastic forming, casting modification, surface composites & surface modification. Mechanical properties can be enhanced by this process. The present study is an experimental investigation to study effect of important friction stir processing(FSP) process parameters on hardness of surface modified 60/40 brass plates. For optimization & prediction of hardness (HRB), Taguchi orthogonal array based design of experiment technique is employed. Experimental runs are planned as per L9 orthogonal array. Three factors are considered: Tool rotation speed, Tool travel speed and Number of passes. Tool rotation speed is varied at three levels (710, 1000 and 1400 rpm), while tool travel speed is varied at three levels (20, 28 and 40 mm/min). Tool tilt angle and plunge depth are kept constant. Optimum combination of process parameters setting is found: tool rotation speed of 1000 rpm, tool travel speed of 20 mm/min & 2 No. of passes. Confirmation runs carried out to confirm the results. There has been observed improvement by 21% in hardness (HRB) values than that at initial FSP parameter settings. Analysis of Variance (ANOVA) indicated that effect of all considered parameters on hardness (HRB) is significant.