Electrochemical Study on Impact of AC on Cathodic Protection Potential for X70 Steel

The application of the traditional criteria for cathodic protection of X70 steel in the presence of AC interference was studied, and the method to determine the scope of the cathodic protection potential and the smallest cathodic protection potential was established. The results show that the traditional cathodic protection criteria was valid with no AC interference, but when there was AC interference the lowest protection potential was negativelu shifted. It is suggested that under the experimental conditions the smallest cathodic protection potential of X70 steel at a smaller AC voltage was -815 mVSCE, while at a larger Al valtage -835 mVSCE around.