The Effect of Exposure Angle on the Corrosion Behavior of Low-Carbon Microalloyed Steel Under CO₂ Conditions

Corrosion experiments were performed with low-carbon microalloyed steel under static and flowing carbon dioxide (CO₂) conditions at different exposure angles. The results showed that the sample facing downward had the lowest corrosion rate, while the sample that was vertically situated had the highest, under static condition. The corrosion scales were studied by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), and Cu Kα x-ray diffraction (XRD). The morphology, impedance, and residual stress of the scales were found to differ, but the compositions were the same under the static condition. When the sample was vertically positioned under static condition, the possibility of localized corrosion occurrence increased. The scale with higher fracture toughness provided better protectiveness. However, under the flowing condition, the exposure angle did not affect the corrosion behavior of low-carbon microalloyed steel.