Influence of the Structure of Carbon Steels on the Corrosion, Hydrogenation, and Corrosion Cracking in Hydrogen-Sulfide Media

We study the influence of the structure of carbon steels on corrosion, hydrogenation, and corrosion cracking in NACE solution. The corrosion and hydrogenation rates of U8 steel increase with the range of particle sizes in the structure in the following order: pearlite, sorbite (high-temperature martensite), troostite (medium-temperature martensite), and martensite. In 45 steel, these rates are maximum for the ferrite-pearlite structure and minimum for sorbite. The 45 steel is less susceptible to hydrogen-sulfide corrosion cracking in a NACE solution than U8 steel, which reveals the dependence on the content of carbon and, hence, on the content of carbides. The 45 steel with sorbite structure and U8 steel with sorbite and troostite structures are characterized by the highest resistance to fracture in hydrogen-sulfide media. However, in view of the influence of hydrogenation, steels with sorbite structures prove to be most suitable for operation in hydrogen-sulfide-containing media.