PSI - Issue 13

M.S. Khoma et al. / Procedia Structural Integrity 13 (2018) 2184–2189 2189 6 M.S. Khoma, V.R. Ivashkiv, M.R. Chuchman, Ch.B. Vasyliv, N.B. Ratska, B.M. Datsko / Structural Integrity Procedia 00 (2018) 000–000 Conclusions The steels У8 and 45 with the structure of martensite are the most predisposed to hydrogen sulfide corrosion cracking. The predisposition of other structures grows in the rows: troostite, sorbite, pearlite (steel У8) and sorbite, ferrite-pearlite, troostite (steel 45). Consequently, the resistance to hydrogen sulfide corrosion cracking of these steels is determined by both the concentration of hydrogen and the localization of corrosion processes, which can enhance or reduce the effect of each other. Microelectrochemical heterogeneity of steels 45 and У8 increases significantly as the result of corrosion in the hydrogen sulfide medium. The displacement of the electrode potentials reaches especially in non-equilibrium structures of the troostite and martensite. This confirms the appearance of local corrosion areas on the surfaces. The predisposition of steels to hydrogen sulfide corrosion cracking in a solution NACE depends on the concentration of carbon and, accordingly, the content of carbides in them. The steel 45 is more resistant to fracture than the У8. References D.Shoesmith, P.Taylor, M. Bailey, D. Owen, 1980. The Formation of Ferrous Monosulfide Polymorphs During the Corrosion of Iron by Aqueous Hydrogen-Sulfide at 21-OC. Journal of Electrochemical Society. 127, 1007 – 1015. H. Ma, X. Cheng, G. Li, and other, 2000. The influence of hydrogen sulfide on corrosion of iron under different conditions. Corrosion Science. 42, 1669 – 1683. H.Hagi, 1994. Effect of Interface between Cementite and Ferrite on Diffusion of Hydrogen in Carbon Steels Materials Transactions, 35, 168-173. J.Ćwiek, 2009. Hydrogen degradation of high-strength steels. Journal of Achievements in Materials and Manufacturing Engineering. 37, 193–212.