Comparative Study of Mechanical Properties in Tig and Mig Welding: Influence of Current on Hardness and Tensile Strength

This study presents a comparative investigation on the mechanical properties of Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) welding techniques. The aim of the research is to evaluate how varying current levels influence the hardness and tensile strength of welded joints, which are critical parameters for structural applications in manufacturing and fabrication industries. The methodology involved conducting a series of hardness and tensile tests on specimens welded using TIG and MIG techniques under 70A, 80A, 90A and 100A current settings. Mild steel was welded using two types of joints, single Lap joint for tensile testing and single v-groove Butt joint for hardness testing. For the hardness test, Rockwell B scale (HRB) was used, and for the tensile strength test, a Universal Testing Machine was employed. Both welding methods were tested under similar conditions to ensure consistency in comparative analysis. The results revealed that TIG welding produced higher hardness values, ranging from 42 to 48 HRB, whereas MIG welding yielded lower hardness in the range of 27 to 39 HRB. Notably, there was no significant variation in hardness with increasing current for either method. In terms of tensile strength, MIG welding achieved superior results, with strength values between 12 and 17.85 kN. The highest tensile strength (17.85 kN) was observed at the lowest current setting (70A), indicating an inverse relationship between current and tensile performance in MIG welding. TIG welding, on the other hand, showed more consistent tensile strength around 10 kN, regardless of current changes. This study concludes that TIG welding is more suitable when high surface hardness is desired, while MIG welding is preferable for applications requiring greater tensile strength. The findings provide valuable insights for selecting appropriate welding methods based on specific mechanical performance requirements.