The Evaluation of the Corrosion Resistance of Materials under the Conditions of Moisture Condensation in the Presence of Carbon Dioxide

The aspects of the development of corrosion processes under the conditions of moisture condensation in the gas phase in the presence of carbon dioxide which lead to the formation of local damage at gas extraction sites are studied. A procedure for conducting the corrosion testing of steels under such conditions is developed and tested. The causes of local corrosion and the degree of the corrosive action of moisture condensation on steel in a carbon dioxide atmosphere are analyzed. It is found that condensation of a large amount of moisture on the surface of steel occurs in the case of a temperature differential, which leads to an increase in the rate of both general and local corrosion. The increased localization of corrosion processes under the conditions of moisture condensation in the presence of CO 2 becomes the reason why the indicator of the depth of corrosion of steel is much higher than the total rate of corrosion. When evaluating the corrosive aggressiveness of the environments with the condensation of the aqueous phase, the indicators of the rate of corrosion associated with the depth of corrosion damage should be taken into account. It is determined on the basis of the test results that the degree of localization of corrosion under the conditions of moisture condensation is higher for the samples cut out from the welded seam when compared to the samples cut out from the parent pipe.