Choosing a carbon steel for effective CO2 corrosion tests in the laboratory

The sulfur (S) content of cal bon steel (CS) appears to influence its carbon dioxide (CO2) corrosion rate. In low-shear, stirred laboratory tests, high-S CS gives a significantly smaller CO2 corrosion rate than low-S CS. This is consistent with the formation of a sulfide surface film in the high-S case. The surface film or other protective mechanism disappears in dynamic tests. The S effect is not of any practical value for corrosion inhibition in the field because only low-S CS have the necessary weldability and mechanical properties. However, he effect does mean that it is important to avoid high-S CS when manufacturing specimens for routine laboratory tests on oilfield corrosion inhibitors or field corrosion monitoring probes.