CORROSION BEHAVIOR OF CARBON STEEL IN H_2S-HCL-H_2O AT 90℃ II-The Effect of HCl Concentration on Corrosion Behavior of Carbon Steel in H_2S Solutions

The electrochemical behavior of SAE-1020 carbon steel in acidic simulation solutions containing H_2S with different concentrations of HCl at 90℃was investigated by mass loss method,electrochemical measurements, SEM observations and XRD.The results indicated that the cathodic depolarization was promoted greatly and the corrosion rate of carbon steel increased remarkably with the increase of HCl concentration in H_2S-containing solutions.Large numbers of corrosion holes formed on carbon steel in H_2S-containing solution without HCl,whereas only the uniform corrosion characteristic was observed on carbon steel surface in the simulation solutions containing different concentrations of HCl.Mackinawite was the sole corrosion product formed on the carbon steel surface in the H_2S-containing solutions with and without HCl.