The Paton Welding Journal, 2024, №11



2024 №11 (02)

DOI of Article 10.37434/tpwj2024.11.03

2024 №11 (04)

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The Paton Welding Journal, 2024, #11, 20-29 pages

Corrosion-mechanical state of the heat pipeline after long-term operation

P. Yukhymets¹, L. Nyrkova¹, R. Dmytriienko¹, H. Kaminski², C. Zaruba², P. Linhardt², G. Ball², V. Yehorenko³

¹E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. Е-mail: yupeter@ukr.net
²Technical University of Vienna. Karlsplatz 13, 1040 Vienna, Austria
³CE “Kyivteploenergo”. 5 Ivan Franko Sq., 01001, Kyiv, Ukraine

Abstract
Metal properties of heat pipeline areas thinned under operating conditions is necessary component for determining its real state, and therefore their research is an actual task. The work investigates the corrosion-mechanical state of a heating pipeline made of BSt3sp steel after more than 40 years of operation. Based on the conducted research, it was established that corrosion of the feeding pipeline is more severe than that of the return pipeline, while the external corrosion of the pipelines is more intense than the internal one. The cracking of the oxide layer accelerates with increasing stresses in the range of the design pressure and leads to the activation of corrosion processes and formation of through defects that prevents destruction by the mechanism of low-cycle fatigue. It is shown that tensile and yield strength of steel correspond to the minimum normalized values. The reduction in plasticity of the feeding pipeline metal does not exceed 10 %, while that for return pipeline is below the minimum normalized value which is probably due to strain aging. The least damaged layer adjacent to the inner surface of pipes has increased strength and plasticity characteristics due to the pipe manufacturing technology. While hydraulic test may not lead to the expected destruction at the location of through defects, its probability raises with increase of the test pressure.
Keywords: heat pipelines, corrosion, mechanical properties, hardness, through defects

Received: 12.09.2024
Received in revised form: 14.10.2024
Accepted: 02.12.2024

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Suggested Citation

P. Yukhymets, L. Nyrkova, R. Dmytriienko, H. Kaminski, C. Zaruba, P. Linhardt, G. Ball, V. Yehorenko (2024) Corrosion-mechanical state of the heat pipeline after long-term operation. The Paton Welding J., 11, 20-29.

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