www.tjprc.org SCOPUS Indexed Journal editor@tjprc.org THE DETERMINATION OF OPTIMUM PARAMETERS FOR MULTI- PERFORMANCE CHARACTERISTICS IN PULSED GAS METAL ARC WELDING OF AISI 904 L SUPER AUSTENITIC STAINLESS STEEL USING GREY RELATIONAL ANALYSIS P. MANAVALAN & S. RAVI Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India ABSTRACT Welding input parameters play a vital role in determining the quality of a weld joint. The quality of the joint can be defined in terms of mechanical properties and weld-bead geometry. Generally, all welding processes are employed with the aim of obtaining a welded joint with the desired characteristics. The purpose of this study is to propose a method to decide near optimal settings for the welding process parameters in pulsed gas metal arc welding (P-GMAW) of AISI 904L super austenitic stainless steel by using grey relational analysis. Grey relational analysis was applied to optimize the input parameters by considering multiple output variables simultaneously. The welds were performed on a sheet with a thickness of 5 mm and a filler wire of diameter of 1.2 mm and their levels of different process parameters were Peak Current (Ip), Pulse Time (tp), Pulse Frequency (f), back ground current (Ib) and welding speed (S) which were considered as input responses. The central composite rotatable design was used to carry out the experimental design and predict the effects of input and output responses. In this study, the output responses considered were bead width, tensile strength, % of elongation, impact strength and microhardness of the welds. The main objective of this work is to determine the P-GMAW process parameters to maximize the tensile strength, % of elongation, impact strength and microhardness and minimize the bead width of the processed joints. This study describes how to obtain near optimal welding conditions over a wide search space by conducting relatively a smaller number of experiments. ANOVA analysis was carried out to identify the significant factors affecting tensile strength, % of elongation, impact strength, microhardness and bead width and further to experimentally validate the optimized parameters. Further investigation was carried out to study the mechanical and metallurgical properties of the optimized parameter weld joints. KEYWORDS: P-GMAW, Tensile Strength, Impact Strength, Microhardness, Weld Bead Width & Grey Relational Analysis Received: Dec 01, 2018; Accepted: Dec 20, 2018; Published: Jan 08, 2019; Paper Id.: IJMPERDFEB201930 1 INTRODUCTION The quality of the weld joint is largely determined by the optimal selection of arc voltage and welding current. It is reported that variation of the rated values of arc voltage and welding current leads to defects like spatter, lack of fusion and melt through etc. These variations mainly depend on the power source construction and it is difficult to generalize in terms of analytical or empirical models. This is primarily due to lack of understanding of characteristic response to current and voltage relationship under static and dynamic conditions of welding resulting in more complication to operate the welding process in critical applications. Therefore, metal transfer in conventional GMAW cannot be regulated as independent of heat input, but, in pulsed gas metal arc welding Original Article International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN(P): 2249-6890; ISSN(E): 2249-8001 Vol. 9, Issue 1, Feb 2019, 305-318 © TJPRC Pvt. Ltd.