Effect of pH Value on Electrochemical Corrosion Behavior of X80 Pipeline Steel in Simulated Ku′erle Soil Solution

The effect of pH value on electrochemical corrosion behavior of X80 pipeline steel in simulated Ku′erle soil solution was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve, and the morphology of corrosion surface was observed using optical microscopy. The results show that the corrosion rate of X80 steel presented a gradually decreasing trend with the increase of pH value. When the simulated solution was weakly acidic, product films were destroyed and there were many corrosion pits on the surface of the X80 steel. When the simulated solution was alkaline, corrosion product films protected the metal from corrosion. When the pH value of the simulated solution was 10.5, there were passive films on the surface of the X80 steel, the corrosion phenomenon was not obvious, only a few small corrosion pits existed on the surface.