Effect of Area-to-Volume Ratio on Pitting Corrosion Behavior of L245M Steel in Simulated Water Accumulation Environment Containing CO₂ in Pipeline

Taking area-to-volume ratio as a variable, the pitting corrosion law of L245M steel in simulated water accumulation environment containing CO₂ in pipeline was studied by means of corrosion immersion test, electrochemical test and ultrasonic scanning microscopy. The results show that the main corrosion morphology of L245M steel was pitting corrosion, the pitting rate increased first and gradually became stable with the increase of area-to-volume ratio. When the area-to-volume ratio was 10 mL/cm², platform corrosion occurred. The corrosion products were mainly composed of FeCO₃, with loose texture and had no protection for the substrate. The charge transfer resistance played a leading role in the corrosion system. Within a certain range, as the area-to-volume ratio increased, the charge transfer resistance decreased and its gradient of change gradually decreased.