Effect of Shielding Gas on Mechanical and Metallurgical Properties Using MAG Welding for J4-Welded Joint

Arc welding is widely used as a joining process in the fabrication industry. Shielding gases used in arc welding are argon, carbon dioxide, and helium. There are situations where we use a combination of these gases to obtain the desired effect. In the present research work, an attempt has been made to weld Jindal J4 with different combinations of carbon dioxide and argon keeping heat input and another parameter constant. The process used for joining was MAG welding, which has a wide presence in the industry due to its many salient features. This work was carried out to study the mechanical behavior of welded joints in austenitic stainless steel J4. Type J4 is suitable for replacing chromium–nickel grades 301, 304 in many applications. The responses measured were impact strength, hardness, the microstructure of heat-affected zone, and their chemical composition. The hardness of the joint and depth of penetration to width ratio decreases, whereas impact strength increases with the increase in percentage of CO2. Less spatter and fumes were observed at 65% argon and 35% CO2.