Impact Factor(JCC): 1.9586 - This article can be downloaded from www.impactjournals.us IMPACT: International Journal of Research in Engineering & Technology (IMPACT: IJRET) ISSN (E): 2321-8843; ISSN (P): 2347-4599 Vol. 3, Issue 7, Jul 2015, 63-70 © Impact Journals A STATISTICAL ANALYSIS OF JOINT STRENGTH OF DISSIMILAR ALUMINIUM ALLOYS FORMED BY FRICTION STIR WELDING USING TAGUCHI DESIGN APPROACH, ANOVA FOR THE OPTIMIZATION OF PROCESS PARAMETERS MOHAMMED YUNUS 1 & MOHAMMAD S. ALSOUFI 2 1, 2 Department of Mechanical Engineering, Umm Al Qura University, Mecca, Kingdom of Saudi Arabia ABSTRACT Friction Stir Welding (FSW) is a solid state joining process, eliminates the drawbacks of common fusion welding are widely used in ship building, aviation and automotive industries. In the present work an attempt has been made to optimize the process parameters of friction stir welding between two dissimilar aluminium alloys (AA7075 and AA6061) to evaluate the output quality characteristics using Taguchi design method. An interaction effect of input parameters is also studied to predict their influence on the output response. Five control factors of mixed levels (2 and 3 levels), L18 orthogonal array are selected to determine the optimum condition for process parameters to improve the performance of FSW. The performance of FSW for dissimilar alloys of aluminium is evaluated in terms of joint’s yield strength, Taguchi technique has been employed using orthogonal array, S/N ratio followed by ANOVA (analysis of variance) to study contribution of each parameter and interaction of them on output and confirmation tests at 95 % confidence level to compare with experimental results. Optimal combination of parameters is presented with a good agreement found between the estimated and experimental results within the preferred significant level after verifying experimentally. It was confirmed that Taguchi design method with ANOVA and confirmation tests successfully improved the quality characteristics of yield strength of FSW process. KEYWORDS: Design of Experiments (DOE), Taguchi Design Method, Signal To Noise (S/N) Ratio, Optimization, FSW, ANOVA, Confirmation Tests INTRODUCTION Due to rise of need in recent times for joining material processes to be fast, efficient and environmental friendly, possessing higher mechanical properties such as yield strength, hardness and tensile strength. With the recent advancements in science and technology, Friction stir welding (FSW) has become alternate to the welding process and it is a solid state joining without melting the metal but by using third member as a tool joining two butted faces of similar or dissimilar metals (Roy, R.K et al. 2001). Heat is generated between the metal surfaces and tool leads to very soft region near tool. FSW tool is cylindrical shouldered non consumable with profiled probe like pentagonal, straight and tapered threaded can be fed at constant rate into a butt joint between two butted material. Primarily FSW used on aluminium Al and its alloys but now they are also extended to copper, magnesium and different material combinations. The advantages of FSW are low defects, free from melt related defects, high joint strength; no filler induced defects, low hydrogen contents. The different types of joint can be produced are butt, corner, lap, T, Spot, Fillet, hem joints, hollow objects such as tanks, tubes, pipes, stocks, of different thicknesses, tapered sections and even 3-D contoured parts. Most of the present research focuses on similar aluminium sheets FSW and a little work carried on dissimilar