Pitting Corrosion of Carbon Steel in Sodium Chloride Solutions with H2S

Issue 4(78) 2015
Pages 34-44

O.N. Bystrova, A.M. Saifutdinov

Kazan National Research Technological University, Kazan

Keywords: carbon steel, industrial scale, solutions of sodium chloride, hydrogen sulfide, local damage, pit depth, frequency diagram, pit depth distribution curves

The results of research of local corrosion of carbon steel St3 covered with industrial scale in neutral and saturated with hydrogen sulfide (pH=4,5) solutions of sodium chloride in potentiostatic conditions during 5 hours were presented. For quantitative adjective of local corrosion the method of corrosion centers calculation was used. These data were grouped over appointed previously selected the pit depth ranges (segments). Frequency diagrams and pit depth distribution curves were constructed. Exponential character of pit depth distribution for carbon steel covered with a production scale was considered. It has been shown the influence of hydrogen sulfide and NaCl concentration on the number of incipient (metastable) pits and appearance of deep local (stable) centers of corrosion.