Weld Bead Geometry Enhancement in A-TIG Welding of AISI 316L Using SiO? Flux Optimized Through Taguchi Method

This research focuses on the enhancement and optimization of weld bead geometry in AISI 316L austenitic stainless steel using the Flux-Activated Gas Tungsten Arc Welding (A-TIG) process. Although conventional TIG welding is widely used due to its superior weld quality and control, it is limited by shallow penetration, which often requires multiple welding passes. This leads to increased heat input, higher distortion, and reduced process efficiency. The ATIG technique overcomes these limitations by applying an activating flux on the workpiece surface, which modifies weld pool behavior through arc constriction and reversal of Marangoni convection, thereby improving penetration characteristics. In the present study, silicon dioxide (SiOâ‚‚) flux was applied on 6 mm thick AISI 316L plates to investigate its influence on weld bead geometry. The experimental design was developed using the Taguchi L18 orthogonal array, considering key welding parameters such as welding current, travel speed, and pulse frequency. The quality of welds was evaluated in terms of depth of penetration, bead width, and angular distortion. In addition, conventional TIG welding was performed under similar conditions to provide a comparative assessment. The experimental results indicate that A-TIG welding with SiOâ‚‚ flux significantly enhances penetration depth and improves the aspect ratio of the weld bead compared to conventional TIG welding. The improvement is attributed to increased heat concentration at the weld center due to arc constriction effects. Statistical analysis using Signal-to-Noise (S/N) ratios and Analysis of Variance (ANOVA) revealed that welding current is the most influential parameter affecting penetration, followed by travel speed and pulse frequency. The optimal parameter combination was identified and validated through confirmation experiments. It can be concluded that the application of SiOâ‚‚ flux in A-TIG welding is an effective and economical approach for achieving deeper penetration, reduced distortion, and improved welding efficiency in AISI 316L stainless steel. The findings of this study provide valuable insights for industrial applications where high-quality, single-pass welding is required, particularly in sectors such as petrochemical, marine, and power generation industries.