Sulfate-Reducing Bacteria-Induced Corrosion Behavior of L415 Pipeline Steel in Southern Jiangxi, China

Microbiologically influenced corrosion (MIC) caused by sulfate-reducing bacteria (SRB) poses a severe threat to oil and gas transmission pipelines. This study investigated the corrosion behavior of L415 pipeline steel in an SRB environment in the acidic soil of southern Jiangxi, China, by employing weight loss measurements, electrochemical measurements, and surface analysis. The growth curve revealed that the SRB, isolated and purified from soil samples in the Southern Jiangxi region, exhibited high activity in an acidic soil environment and further adhered to the surface of the specimen, ultimately leading to MIC of the pipeline steel. The experimental results showed that by reducing SO₄ ^2-, SRB could enhance cathodic reactions. The Fe²⁺ from anodic dissolution reacted with S^2- to form FeS, significantly accelerating corrosion. Additionally, the formation of FeS-SRB/Fe galvanic couples, formed on the surface of L415 pipeline steel specimens, promoted the localized corrosion. The depth of the pitting corrosion increased with the extended immersion time. These experimental results would provide theoretical references for the practical application of pipeline engineering in China and the corrosion control of the SRB environment in southern Jiangxi.