IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 6, Issue 6 (May. - Jun. 2013), PP 24-30 www.iosrjournals.org www.iosrjournals.org 24 | Page A Review: Parametric effect on mechanical properties and weld bead geometry of Aluminium alloy in GTAW Lakshman Singh 1 , Davinder Singh 2 , Pragat Singh 3 1 M.Tech. scholar, Dept. of Mechanical Engineering, UCOE, Punjabi University, Patiala, India 2 Assistant Professor, Dept. of Mechanical Engineering, UCOE, Punjabi University, Patiala, India 3 Assistant Professor, Dept. of Mechanical Engineering, UCOE, Punjabi University, Patiala, India Abstract: Gas tungsten arc welding (GTAW) is high quality and high precision welding process which are suitable for welding thin metals. Inert gas as helium and argon are used as a shielding gas to prevent the weld bead from air, dust and other contaminations in welding. There are so many welding process parameter affect the weld quality in GTAW. Important process parameter which mainly affect the weld quality are welding current, arc voltage, welding speed, gas flow rate, heat input, gun angle, stand of distance and specimen thickness. Important quality parameters in GTAW process are depth of penetration and weld bead geometry. Depth of penetration and weld bead width both are affected by welding speed. As welding speed increases, depth of penetration increases but weld bead width decreases. The weld joint quality can be assessed in terms of weld bead geometry, mechanical properties and distortion. Post weld heat treatment is done to improve the weld quality by solutioning and aging which results in refinement of grain size and thus, mechanical properties of weld joint improved. Heat input effects the filler rod deposition rate in the form of droplets in weld bead. This paper covers review of process parameters of GTAW and their effect on weld quality. Keywords: Depth of penetration, GTAW, Heat affected zone, mechanical properties, Parametric effect, Weld bead geometry. Contents 1 Introduction 2 Gas tungsten arc welding process 2.1 Gas tungsten arc welding process parameters 2.1.1 Welding polarity 2.1.2 Arc voltage and stand of distance (air gap) 2.1.3 Welding speed 2.1.4 Electrode 2.1.5 Shielding gas 3 Review of weld bead quality 3.1 Parametric effect on heat affected zone (HAZ) 3.2 Parametric effect on weld bead geometry 3.3 Parametric effect on mechanical properties 4 Discussion I. Introduction Welding is fabrication process for joining materials, usually metals or thermoplastics, by the application of heat due to an electric arc produced between electrode and base metal. Significant impact of welding has made on large number of industries due to their raising operational efficiency & productivity of plant. Welding has capability to use in any position such as horizontal, flat, vertical (up and down) and overhead. [1]. Generally, constant current and constant voltage power supplies are available to use for welding the materials. An electric arc directly related to voltage and amount of heat generated related to current [2]. Gas tungsten arc welding is manual welding process in which non- consumable tungsten electrode, an inert gas and a filler rod used. GTAW process is specially preferred for thin materials due to characterizing a stable arc, high weld quality, better reliability, smooth finishing and high productivity [3]. Many factors influence the strength of weld joint and material around them are heat input, weld ability of base material, filler material, arc voltage and design of joint [4]. Aluminium is most abundant metal of low density and corrosion resistant property due to phenomenon of passivation. GTAW is preferred to weld aluminium alloy at low voltage. Aluminium and its alloys has applications to make structural components of aerospace industry, ship building, vehicle bodies, mine skips and pressure vessels [5]. Aluminium has another property of recycling without any loss of its natural qualities. Recycling involves melting the scrap, A Process require only 5% of energy used to produce