Effect of tungsten inert gas welding parameters on the performance of AISI 304 alloy steel using multi-response optimization technique

Abstract

ABSTRACT The demand for improved integrity and reliability of weldment poses a huge challenge to manufacturing industries. In this work, Tungsten Inert Gas (TIG) welding technique was used in the welding of AISI 304 stainless steel, with the aim of investigating the effects of welding parameters (gas flow rate, current, voltage and root gap) on microstructure and mechanical properties. A constant wire feed rate and welding speed of 7 m/min and 15 mm/s, respectively, were utilized throughout the welding process, while experimental design and multi-response optimization were conducted using Taguchi (L934) and grey relational analysis (GRA), respectively. The experimental results revealed that change in welding parameters affects the mechanical properties of the weldment, while analysis of variance results showed that hardness and impact energy are mostly influenced by root gap, current is the most contributing factor on tensile strength. The GRA results revealed that multi-response optimization can be achieved with gas flow rate (5 ml), current (120A), voltage (3 V) and root gap (2.5 mm), while the morphology of the weldment showed heterogeneous microstructure, consisting of finer with few coarse grains of ferrite and pearlite. Also, a percentage error of less than 5% recorded during the validation test represents a good correlation between the experimental and theoretical values.