Study on Corrosion Behavior of X80 Steel in Guangdong Soil with Different Water Contents under HVDC Interference

This paper focused on the variation of DC interference parameters and corrosion behavior of X80 steel interfered by 100 V DC potential in Guangdong real soil with 5 different water contents through indoor simulation experiments. The results showed that there existed obvious differences for the current density changes of X80 specimens in various soil conditions with different water contents under interference of 100 V DC potential. At a lower water content (14%, 18%, 21%), the DC current density reached a peak value in a second and then dropped to a stable value rapidly, and the drop rate exceeded 60%. When the water content reached 35% or 43%, the current density reached a peak in about 75 s, and after that there was no obvious downward trend. The stable value accounted for about 80% of the peak value. The corrosion rates in the soil conditions with different water contents of 14%, 18%, 21%, 35%, and 43% were 2.66, 4.12, 5.70, 8.62, and 10.01 µm/h, respectively. The local soil spread resistance contributed to the differences in current density and corrosion rates in different environments. The main corrosion products under HVDC interference were iron oxides such as α-FeOOH, γ-FeOOH, and Fe3O4.