Comparative analysis of corrosion resistance of pipeline steels exposed to sulfate-reducing bacteria: Insights on L360, L245NS and antibacterial steels

Abstract

In response to the microbiologically influenced corrosion (MIC) issues encountered in oil and gas pipelines, a comparative study was conducted on the corrosion properties and mechanisms of pipeline steels L360, L245NS, and antibacterial steel in environments containing sulfate-reducing bacteria (SRB) using the weight-loss method, surface analysis techniques, and electrochemical tests. The results showed that both the uniform corrosion rate and pitting rate followed the order: L360 > L245NS > antibacterial steel. Electrochemical tests further confirmed that the antibacterial steel demonstrated superior corrosion resistance, with the highest self-corrosion potential and a corrosion current density one-fifth that of L360 steel. Additionally, the antibacterial steel is more prone to passivation in the SRB environment. After 7 days of exposure, the sum of its charge transfer resistance and biofilm resistance was approximately 2.9 times that of L245NS steel and 3 times that of L360 steel. The addition of Cu to the antibacterial steel may contribute to inhibiting microbial growth and preventing biofilm formation, though this mechanism is controversial.