Corrosion Behavior of Corrosion Resistant Steel for Upper Deck in Cargo Oil Tank

The corrosion behavior of a new type of corrosion-resistant steel applied to a super-large oil tanker in the corrosive environment of the upper deck of a simulated cargo oil tank was studied by methods such as weightlessness method, XRD, SEM/EDS, etc. The results showed that the corrosion-resistant steel used for upper deck in the cargo oil tank was uniformly corroded in O₂-CO₂-H₂S-SO₂-N₂ mixed gas. The corrosion rate of the new type of corrosion-resistant steel in the later stage of the test was about 0.20 mm/a. The main components of corrosion products were α-FeOOH, FeS₂, FeSO₄·H₂O. Among them, the stable phase α-FeOOH had the largest content, and the spherical α-FeOOH was continuously generated and gradually densely formed into clusters at the micro level. In the later stage of the test, the rust layer on the surface of the corrosion-resistant steel was relatively dense and uniform without delamination, and there were fewer defects such as cracks and breakages.