Corrosion and stress-corrosion cracking of exploited storage tank steel

We study the corrosion resistance of St3S steel under loading and its susceptibility to corrosion and hydrogen-induced cracking in bottom water. Sections of a tank are distinguished according to the character of the media interacting with the metal of the inner surface in the process of operation. It is shown that bottom water is characterized by high levels of corrosion activity and that the degrees of in-service degradation of different sections of the tank are different. The worst corrosion and stress-corrosion resistance are exhibited by steel operating in contact with bottom water. Significant levels of plastic strains intensify the process of corrosion in steel and make the rates of corrosion in different sections of the tank closer to each other. The in-service degradation of steel can not only intensify the process of corrosion of the inner surface of the tank but also promote the brittle fracture of the material characterized by the elevated susceptibility to hydrogen-induced cracking.