Page 21 - НАЦІОНАЛЬНА АКАДЕМІЯ НАУК УКРАЇНИ

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Выявлен эксплуатационный распад перлита в стали 20 при катодной защите
трубопровода, который сопровождался снижением коррозионной стойкости и
повышением концентрации водорода. Установлено преимущества использования
для заземлителей эксплуатационно деградированных труб. Зафиксировано
эксплуатационное снижение склонности к питтингообразованию и повышение
коррозионной стойкости стали 12Х18Н10Т, что требует дополнительного
количества анодов, однако увеличивает их ресурс.
Предложен метод повышения эффективности анодных заземлений
активаторами. Разработана конструкция заземления, которая позволяет

контролировать сопротивление в системе анод–грунт использованием технических
растворов.
Ключевые слова: сталь, активные вещества, анодное заземление,
электрическое сопротивление, катодная защита, коррозия.

ABSTRACT

Usov D. I. Improving the efficiency of long-term operated anodic groundings of
cathodic protection system of pipelines. – Qualification scientific work as the
manuscript.
Thesis for the Candidate’s degree in engineering sciences by speciality 05.17.14 –
Сhemical resistance of materials and corrosion protection. – Karpenko Physico-
Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, 2021.
The dissertation is devoted to the establishment of electrochemical features and
regularities of degradation of ferrite-pearlite and austenitic steels of pipelines under
cathodic protection, its impact on the state of anode groundings over a long service
life, as well as the development of the methods to improve their efficiency and extend
the resource.
Significant changes in the microstructure of the low carbon ferrite-pearlite 20 steel
as a result of its long-term operation under cathodic protection of pipeline under high
pressure were revealed: an increase in the portion of ferrite because of the decomposition
of pearlite. They were accompanied by an increase in the concentration of residual
hydrogen, a significant decrease in the corrosion resistance and some mechanical
properties but not enough noticed from the point of a loss structural strength of pipe
groundings. It has been established that the 20 steel operated for 51 years having the
highest hydrogen content (more than in order in comparison with the initial steel state) is
characterized by the lowest corrosion resistance in 3% NaCl (1.6 times lower than that of
steel in the initial state) and the highest portion of ferrite due to the operational
decomposition of pearlite, which indicates a special role of hydrogen in degradation
process. The advantage in the usage of degraded pipes after preliminary operation for
anodic groundings has been shown, which are characterized by increased current output
due to the operational decrease of their corrosion resistance.
For anodes manufactured from the austenitic 12X18H10T steel as alternative for
carbon steels a decrease in pitting and an increase in corrosion resistance by 7.8-13 times,
depending on the distance from the drainage point after 2.5 years of operation, compared
with steel in the initial state, have been revealed. Such an effect of groundings operation