Influence alloying elements and steel AISI 321 structural heterogeneity on the selective dissolution of metals from pitting

Abstract

Results of research of influence of a chemical composition and structural heterogeneity of AISI 321 steel are presented in article on its corrosion losses ΔCr, ΔNi and ΔFе from pittings in modeling in modeling (cloride circulating) waters with pH4…8 and concentration of chlorides of 600 mg/dm3. It is shown that mechanisms of corrosion losses of Cr, Ni and Fe from metastable and stable pittings are caused by characteristics of their selective dissolution. In particular, the surface of metastable pittings is enriched with Fe and Cr and Ni is impoverished, and stable – Cr is enriched and Ni and Fe is impoverished. It promotes reorganization of volume of steel under a surface of pittings owing to solid-phase diffusion of atoms of Fe, Cr and Ni which depends on nature of pitting and рН model reverse waters.