Optimization of the tungsten inert gas welding parameters of mild steel thin sheets through the gray relational analysis method

Welding techniques are widely utilized for permanent material joining. The tungsten inert gas (TIG) welding process is notable for its exceptional precision, controlled heat input, and affordable equipment. It is widely employed for joining different grades of steel. Currently, extensive research is being conducted to enhance the quality of welded joints. This involves exploring various welding methods and adjusting welding parameters to improve characteristics such as strength, ductility, formability, appearance, and corrosion resistance. The current investigation’s main aim consists of studying the effect of the welding parameters, i.e., the welding current and the gas flow rate, on the mechanical properties of welded joints of low-carbon steel with a thickness of 1 mm. The yield strength, tensile strength, and strain at break are selected as responses. The analysis of variance (ANOVA) is utilized to check the impact of welding parameters on the responses, while the Gray Relational Analysis (GRA) is used to optimize the welding parameters to maximize the chosen responses. Results show that welding current possesses the most influence on the three responses, i.e., the yield strength, tensile strength, and strain at break. The combination of 65 A welding current and 15 l/min gas flow rate allows the maximization of the three responses.