Stress corrosion cracking response of AISI 304L stainless steel welds of C-TIG and A-TIG under chloride environments

Abstract Stress corrosion cracking (SCC) of stainless-steel welds in chloride-containing environments remains a major concern in structural and process industries. Although Activated Tungsten Inert Gas (A-TIG) welding has been widely investigated for improving weld penetration and mechanical properties, comparative assessment of SCC behaviour of flux-assisted A-TIG welded AISI 304L stainless steel remains limited. This study investigates the SCC response of AISI 304L stainless steel welds fabricated using conventional TIG (C-TIG) and A-TIG welding employing SiO 2 , TiO 2 , and Cr 2 O 3 activating fluxes under chloride environments. SCC susceptibility was evaluated using Slow Strain Rate Testing (SSRT) in air and 3.5 wt.% NaCl solution. Mechanical degradation behaviour, time-to-failure response, fracture morphology, and localized compositional variations were comparatively assessed. Chloride exposure reduced the mechanical performance of all weld conditions. Among the investigated welds, TiO 2 -assisted A-TIG exhibited the most favourable SCC resistance, achieving a time-to-failure of 115 min compared with 98 min for the C-TIG weld. The SCC susceptibility indices further revealed lower degradation in strength and ductility for TiO 2 -assisted welds (Iσ ≈ 4.18% and Iε ≈ 10.82%) than for C-TIG welds (Iσ ≈ 15.96% and Iε ≈ 28.19%). Fractographic analysis also indicated comparatively reduced crack propagation in TiO 2 -assisted welds. The SCC resistance trend under the investigated conditions was established as TiO 2 A-TIG > Base Metal > Cr 2 O 3 A-TIG > SiO 2 A-TIG > C-TIG. The study provides a direct comparative assessment and performance-based ranking of activating fluxes with respect to SCC behaviour of AISI 304L stainless steel welds exposed to chloride environments.