Abstract
Previous work on anodic polarization and anodic protection of carbon steel in sulfuric acid has neglected to consider the possible effect of differences in steel microstructure on polarization behavior. If such differences do affect anodic-polarization behavior of the steel, it would be important to recognize this fact when, for example, anodic protection is applied to a welded steel vessel containing heat-affected zones of varying microstructure.
In the present work, anodic polarization curves were determined in three concentrations of sulfuric acid for samples of carbon steel that had been heat-treated to produce various microstructures. In general, results showed that microstructural differences, had only a minor effect on polarization behavior. Therefore, when anodic protection is applied to carbon steel in sulfuric acid, micro-structural differences resulting from heat treatment of steel should not be a critical factor. Test results also indicated that carbon content of the steel had little effect on anodic polarization. Evidently, anodic-polarization behavior is. determined primarily by the ferrite phase and is relatively unaffected by the amount or distribution of the cementite phase.