the paper presents the results of the research that studied how the penetration depth of pitting corrosion in the surface structures of clad steel depends on the steel surface electrode potential. the tests were carried out on the stainless surface of the samples made from steel 09g2S/08X13, which is widely used in production of metal structures for the oil and gas industry due to its necessary mechanical properties and corrosion resistance. the operation process of this steel runs in the technological environment with high corrosivity. the influence of pitting components of the corrosive medium (Сlи S 2 o 3 2ions) on the diffusion of oxidants and the development of local processes of destruction of a passive film is shown. it is noted that the maximum influence of the electrode potential on the development of pitting corrosion occurs in the area of secondary passivation. in this case, the depth of pitting can reach 180 μm. Further displacement of the electrode potential of the surface contributes to the phenomenon of transmissivity and leads to the appearance of significant mechanical stresses in the surface structures, causing their cracking. investigation of surface structures will establish mechanisms for their destruction, and timely implement the necessary anticorrosion measures.

The article describes a method developed to evaluate the mechanism of local corrosion processes on the surface of a clad layer of steel specimens, which makes it possible to identify the difference in electrode potentials in artificially created holes. As a result of the study it was found that in a corrosive medium containing Cl- and S2O32- ions, the diffusion of oxidants into a hole of smaller diameter is difficult, which causes a large potential difference between the wall of the hole and its bottom. This process contributes to the development of local electrochemical corrosion.

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