Mechanism of microbiologically induced anaerobic water-line corrosion of 980 high strength steel in nutrient-rich artificial seawater

The anaerobic water-line corrosion of 980 high-strength steels in artificial seawater containing SRB was investigated. The specimen suffered serious pitting corrosion in the water-line region, where the corrosion rate was about two times higher than that of under water. A great amount of sessile SRB on the surface of the water-line area induced a continuous gully-shaped pitting on the high-strength steel with an average hole depth of 11 µm/14 d. Meanwhile, the different component and structure of SRB biofilms accumulated in water-line and under water regions induced a galvanic effect, which further accelerated the corrosion rate in the liquid-phase coupled region.