Can air carbon arc gouging sensitize stabilized or low-carbon austenitic stainless steel?

Abstract

This paper challenges the widespread skepticism surrounding the use of air carbon arc gouging (ACAG) in repair welding for critical applications in stainless steels, such as oil and gas assets, by evaluating its effects on the electrochemical properties of AISI 316L and AISI 321 austenitic stainless steels. This investigation examines the degree of sensitization and intergranular corrosion susceptibility in a simulated repair scenario. The experimental setup involved creating a gouged groove (6–7 mm depth) adjacent to the heat-affected zone (HAZ) using air carbon arc gouging (ACAG), followed by rewelding via submerged arc welding (SAW). Welded joints were analyzed under three surface preparation conditions after gouging: i) no cleaning, ii) brushing, and iii) rectifying. Electrochemical evaluation was conducted using the double loop potentiokinetic reactivation (DL-EPR) technique in accordance with ISO 12732:2017, while susceptibility to intergranular corrosion was assessed using ASTM A262-15, Practice A, oxalic acid etching tests. The results debunk the prevailing assumption that ACAG inevitably compromises the corrosion resistance of stainless steels. They demonstrate that, even without post-process cleaning, the procedure does not increase sensitization or susceptibility to intergranular attack. These findings validate ACAG as a viable, efficient, and cost-effective method for repair welding in low-carbon or stabilized austenitic stainless steels, simulating field conditions. This includes demanding industries such as oil and gas, where it ensures effective defect removal and full weld penetration while preserving asset integrity and resistance to localized corrosion.