Improvement of Welding Performance on Mild Steel by a Hybrid TIG-MAG Welding Technique

Rapid and effective 'TIG-MAG hybrid welding (TMHW)' technique overcomes the disadvantages associated with traditional welding setups. This research aims to study how different welding parameters affect the appearance of TMHW weld bead geometry (WBG). The study compares the penetration, reinforcement, and weld bead width of TMHW with metal active gas welding (MAGW). The results show that TMHW yields higher penetration and weld bead width with less reinforcement height than MAGW. Microhardness analysis revealed a subtle variation in the microhardness with regard to the heat input conditions and direction from the weld zone. TMHW produces slightly more microhardness in the weld zone. However, no discernible increase in microhardness was observed. The morphological analysis shows that TMHW causes a coarsening of the grains and a weakening of the Widmanstatten structure (WS) compared to MAGW. Grey-based Taguchi optimisation analysis was conducted to determine the best welding parameters for improved welding performance. The polynomial regression analysis determines the relationship between three welding parameters and WBG. The weld toe geometry has also been examined to provide a reference for future studies regarding fatigue. The findings suggest that TMHW with vertical torches can enhance penetration and reduce reinforcement, making it a viable alternative to conventional welding setups for improving welding performance on mild steel (MS) A-2062.