Corrosion of Carbon Steel in Sour Water From the Oil Industry: the Effect of Temperature

In this work, the corrosion behavior of carbon steel AISI 1018 immersed in a sour water sample solution collected from a refinery plant, was studied, varying the temperature between 25 to 50C with and without stirring. Polarization curves indicate negligible modification of anodic branch without stirring; but, the cathodic branch is more sensitive to temperature change. Also, analysis of surface samples by scanning electron microscopy (SEM) shows no film of corrosion products. The values of electrochemical noise localization index (LI), indicate that the sites of localized corrosion increase at 30C. However, when solution is stirred, polarization curves indicate more sensibility in anodic branch and SEM micrographs show different corrosion products. LI shows values approaching 1, indicating sites where localized corrosion is present. These results indicate that the variation in temperature can cause changes in the structure of the corrosion products and thus the severity of damage in the metal surface.