Corrosion Behavior of X70 Steel in CO₂ Wet Gas Top-of-Line Corrosion Environment

The corrosion behavior of X70 steel in static wet gas environment was investigated using a high-pressure high-temperature condensation autoclave,in order to simulate the corrosion environment of top line corrosion (TLC). This experiment studied the influence of localized corrosion occurring on the surface of X70 steel in different test durations and different temperature differences. The composition and morphology of the corrosion scale were characterized by EDS and SEM. And the relationship between the formation of corrosion scale and localized corrosion in TLC was discussed. The results showed that the position of localized damage on corrosion scales corresponded with the position of localized corrosion after removal of corrosion scales. Under the condition of different temperature differences,when the corrosion scales reached a certain thickness,the temperature gradients maybe existed on the corrosion scales,which was more likely to cause corrosion scales to fall off.