ORIGINAL CONTRIBUTION Optimization of Welding Parameters of Submerged Arc Welding Using Analytic Hierarchy Process (AHP) Based on Taguchi Technique A. Sarkar • J. Roy • A. Majumder • S. C. Saha Received: 31 January 2013 / Accepted: 30 April 2014 / Published online: 22 May 2014 Ó The Institution of Engineers (India) 2014 Abstract The present paper reports a new procedure using an analytic hierarchy process (AHP) based Taguchi method for the selection of the best welding parameters to fabricate submerged arc welding of plain carbon steel. Selection of best welding parameters is an unstructured decision problem involving process parameters for multi- ple weldments. In the present investigation, three process parameter variables i.e. wire feed rate (W f ), stick out (S o ) and traverse speed (T s ) and the three response parameters i.e. penetration, bead width and bead reinforcement have been considered. The objective of the present work is thus to improve the quality of the welded elements by using AHP analysis based Taguchi method. Taguchi L 16 orthogonal array is used to perform with less number of experimental runs. Taguchi approach is insufficient to solve a multi response optimization problem. In order to overcome this limitation, a multi criteria decision making method, AHP is applied in the present study. The optimal condition to have a quality weld (i.e. bead geometry) is found at 210 mm/min of wire feed rate, 15 mm of stick out and 0.75 m/min of traverse speed and also observed that the effect of wire feed rate on the overall bead geometry properties is more significant than other welding parame- ters. Finally, a confirmatory test has been carried out to verify the optimal setting so obtained. Keywords Submerged arc welding (SAW)  AHP  Taguchi method  ANOVA analysis  S/N ratio Introduction Submerged arc welding (SAW) process is one of the oldest automatic welding processes developed during the 1930s [1–4] and contributes to approximately 10 % of the total welding needs over the world and is commercially used for welding of low carbon steels, high strength low alloy steels, nickel based alloys and stainless steels [5]. SAW process is widely used in heavy fabrication institutes due to high quality, deeper penetration ability and a smooth bead geometry [6–11]. Apart SAW is preferred over the other methods of welding process, because of inherent qualities likes easy control of process parameters and process vari- ables. The quality is judged by the bead geometry and also the mechanical properties, i.e. weld quality is strongly characterized by the weld bead geometry, which plays an important role in influencing the mechanical properties of the welded joints [12, 13]. Therefore, for finding optimal weld bead geometry (such as penetration, bead width, bead reinforcement), the selection of the optimal welding pro- cess parameters is very essential [14]. The weld bead geometry depends on welding process parameters such as wire feed rate (W f ), stick out (S o ) and traverse speed (T s ) etc. [15]. Chandel et al. [16] reported that the penetration increased with the decrease in electrode extension. There- fore, it is very important to select the optimal welding process parameters. Optimal process parameter setting has derived to yield optimal bead geometry with maximum penetration, minimum bead width and reinforcement in this work. Most of the optimization cases perform with single performance characteristic. But in case of multi perfor- mance characteristic, it is observed that an increase in one response may cause change in another response, while applying the optimal setting of process parameter. Thus for optimized (maximized) quality characteristics of A. Sarkar (&)  J. Roy  A. Majumder  S. C. Saha Department of Mechanical Engineering, National Institute of Technology, Agartala, Agartala 799055, Tripura, India e-mail: sarkarabhijit2009@gmail.com 123 J. Inst. Eng. India Ser. C (April–June 2014) 95(2):159–168 DOI 10.1007/s40032-014-0114-4