Empress Catherine II St. Petersburg Mining University, St. Petersburg, Russia

E. I. Pryakhin, Dr. Eng., Prof., Head of the Dept. of Materials Science and Technology of Art Products, e-mail: e.p.mazernbc@yandex.ru
D. A. Pribytkova, Postgraduate Student, Dept. of Materials Science and Technology of Art Products, e-mail: pribytda@gmail.com

Increasing the service life of pipeline elements of urban heating networks is currently very relevant and therefore an important task. These pipelines, buried in the ground in an urban environment, have an unsatisfactory service life. The main factor is the occurrence of corrosion. These are mainly soil corrosion, microbiological corrosion, stress corrosion cracking and electrochemical corrosion due to the presence of stray currents. They are caused by underground power networks, metro, tram tracks, substations and other sources of high voltage. In many ways, the service life of pipes depends on the composition of the protective coating, but no less important is the quality of its application, which is determined by the method of preliminary preparation of the surface of pipeline parts before applying the protective coating. The paper compares the currently used method of shot-blasting the surface of pipes and the technology of laser surface treatment proposed for use. These two methods are analyzed and evaluated. Metal samples of pipelines of heating mains, made of steel 3, used for the manufacture of pipes in production, were studied in this work in various ways – the roughness and relief of the surface of the samples were evaluated, the change in their microhardness and microstructure of the cut was studied. The influence of surface preparation methods on steel properties and adhesive strength before applying a phosphate layer is considered. The phosphate layer in this case acts as a substrate for the main coating. The quality of its contact – adhesive strength with the metal surface will determine the operational properties of the main protective coating. Poor adhesive properties of the intermediate phosphate layer will lead to flaking of the base layer and a favorable situation for the development of corrosion. In this work, several modes of laser treatment of the surface of prototypes were considered. Based on their comparison, the advantages of laser processing over shot blasting are shown.

1. Semenov A. G. Corrosion protection of heating network pipelines. Novosti teplosnabzheniya. 2017. Vol. 207. No. 11. Available at: http://www.rosteplo.ru/nt/207 (accessed: 19.10.2023).
2. Moskalev I. L., Litvak V. V. Damage to the main components of heat supply networks in cities of the Russian Federation. Izvestiya Tomskogo politekhnicheskogo universiteta. Inzhiniring resursov. 2015. Vol. 326. No. 7. pp. 70–80.
3. Cole I. S., Marney D. The science of pipe corrosion: A review of the literature on the corrosion of ferrous metals in soils. Corrosion Science. 2012. Vol. 56. pp. 5–16. DOI: 10.1016/j.corsci.2011.12.001
4. Kolesnikova N. N., Lukanina Yu. K., Khvatov A. V., Likhachev A. N. et al. Biological corrosion of metal structures and protection against it. Vestnik Kazanskogo tekhnologicheskogo universiteta. 2013. No. 1. pp. 170–174.
5. Byrylov I. F. Determination of the corrosion rate of pipe steels in soils suspensions of various compositions. Izvestiya vuzov. Severo-Kavkazskiy region. Tekhnicheskie nauki. 2011. No. 3. pp. 108–110.
6. Goldobina L. A., Orlov P. S. Analysis of the causes of corrosion damage to underground pipelines and new solutions for increasing the corrosion resistance of steel. Zapiski Gornogo instituta. 2016. Vol. 219. No. 3. pp. 459–464.
7. Poberezhnyi L. Ya. et al. Corrosive and mechanical degradation of pipelines in acid soils. Strength of Materials. 2017. Vol. 49, Iss. 4. pp. 539–549. DOI: 10.1007/s11223-017-9897-x
8. Mustafin F. M. Review of methods for protecting pipelines from corrosion with insulating coatings. Neftegazovoe delo. 2003. No. 1. Available at: http://ogbus.ru/files/ogbus/authors/Mustafin/Mustafin_3.pdf (accessed: 19.10.2023).
9. Vlasov D. Yu., Shidlovskaya A. V., Alexandrova O. Yu. Impact of geobiological and hydrogeochemical processes on the development of corrosion of structural materials in the escalator tunnel of the St. Petersburg metro. Zapiski Gornogo instituta. 2011. Vol. 190. pp. 60–64.
10. Kotyukov P. V. Features of assessing the vulnerability and destruction of structural materials of transport structures in the underground space of St. Petersburg. Zapiski Gornogo instituta. 2010. Vol. 186. pp. 22–26.
11. Bakhtizin R. N., Zaripov R. M., Korobkov G. E., Masalimov R. B. Assessment of the influence of internal pressure causing additional bending of the pipeline. Zapiski Gornogo instituta. 2020. Vol. 242. pp. 160–168. DOI: 10.31897/pmi.2020.2.160
12. Aginey R. V., Firstov A. A. Improvement of the method for assessing bending stresses in the wall of an underground pipeline. Zapiski Gornogo instituta. 2022. Vol. 257. pp. 744–754. DOI: 10.31897/PMI.2022.64
13. Shammazov I., Dzhemilev E., Sidorkin D. Improving the method of replacing the defective sections of main oil and gas pipelines using laser scanning data. (MDPI) Open Access Journal Applied Sciences. 2023. Vol. 13, Iss. 1. 48. DOI: 10.3390/app13010048
14. Aginey R. V., Kapachinskikh Zh. Yu., Isupova E. V., Alexandrov О. Y. Analysis of approaches to designing electrochemical protection systems for underground pipelines in Russia and abroad. Science and Technologies: Oil and Oil Products Pipeline Transportation. 2022. Vol. 12. No 5. pp. 480–488.
15. Alabtah F. G. et al. Towards the development of novel hybrid composite steel pipes: Electrochemical evaluation of fiber-reinforced polymer layered steel against corrosion. Polymers. 2021. Vol. 13, Iss. 21. 3805. DOI: 10.3390/polym13213805
16. Nadirov K. S. et al. The study of the gossypol resin impact on adhesive properties of the intermediate layer of the pipeline three-layer rust protection coating. International Journal of Adhesion and Adhesives. 2017. Vol. 78. pp. 195–199. DOI: 10.1016/j.ijadhadh.2017.07.001
17. Abrashov A. A., Grigoryan N. S., Vagramyan T. A., Akimova E. F. Improvement of crystalline phosphating solutions. Galvanotekhnika i obrabotka poverkhnosti. 2010. Vol. 18. No. 3. pp. 48–52.
18. Fedosov S., Roumyantseva V., Konovalova V. Phosphate coatings as a way to protect steel reinforcement from corrosion. MATEC Web of Conf. International Conference on Modern Trends in Manufacturing Technologies and Equipment: Mechanical Engineering and Materials Science (ICMTMTE 2019), Sevastopol, Russia, September 9–13, 2019. Vol. 298. 00126. DOI: 10.1051/matecconf/201929800126
19. Galedari S. A. et al. A comprehensive review of corrosion resistance of thermally-sprayed and thermally-diffused protective coatings on steel structures. Journal of Thermal Spray Technology. 2019. Vol. 28, Iss. 4. pp. 645–677. DOI: 10.1007/s11666-019-00855-3
20. Studenekin G., Mazurova D., Abrashov A., Grigoryan N. et al. Phosphating of steel in lowtemperature solution. Metall. 2021. pp. 748–753. DOI: 10.37904/metal.2021.4177
21. Olt J., Maksarov V. V., Petrishin G. V., Panteleyenko E. F. et al. Magnetic abrasive machining of hard workpieces by new diffusion-alloyed materials. Russian Engineering Researches. 2023. Vol. 43, Iss. 2. pp. 190–194. DOI: 10.3103/S1068798X23030243
22. Sugama T., Kukacka L. E., Carciello N., Warren J. B. Chemisorption mechanism and effect of polyacrylic acid on the improvement in bond durability of zinc phosphate-to-polymer adhesive joints. Journal of Materials Science. 1987. Vol. 22. pp. 722–736.
23. Pryakhin E. I., Mikhailov A. V., Sivenkov A. V. Technological features of surface alloying of metal products with Cr–Ni complexes in the medium of low-melting metal melts. Chernye Metally. 2023. No. 2. pp. 58–65.
24. Pryakhin E. I., Troshina E. Yu. Degradation induced by thermal and chemical impacts on matrix codes installed on brass and aluminium alloy parts by laser. Tsvetnye Metally. 2022. No. 7. pp. 87–91.
25. Pryakhin E. I., Troshina E. Yu. Study of technological and operational features of hightemperature-resistant composite films for laser marking of parts made of ferrous alloys. Chernye Metally. 2023. No. 4. pp. 74–80.
26. Amiaga J. V., Ramos-Velazquez A., Gorny S. G., Vologzhanina S. A. et al. Groove formation on metal substrates by nanosecond laser removal of melted material. (MDPI) Open Access Journal Metals. 2021. Vol. 11, Iss. 12. 2026. DOI: 10.3390/met11122026
27. Bezyazychny V. F., Scherek M., Pervov M. L., Timofeev M. V. et al. Study of the influence of temperature on the ability of metals to accumulate energy during their plastic deformation. Zapiski Gornogo instituta. 2019. Vol. 235. pp. 55–59. DOI: 10.31897/pmi.2019.1.55
28. Amiaga J., Ramos-Velazquez A., Vologzhanina S. Laser oxide reduction duting multipass relief forming on carbon steel surface. Opt Quant Electron. 2023. Vol. 522. No. 55. DOI: 10.1007/s11082-023-04688-x
29. Petkova A. P., Ganzulenko O. Yu. Laser marking of non-ferrous metal and alloy products using ultradense barcodes: process features. Tsvetnye Metally. 2022. No. 7. pp. 92–97.
30. GOST 9.301–86. Unified system of corrosion and ageing protection. Metal and non-metal inorganic coatings. General requirements. Introduced: 30.06.1987.
31. Starikova E. Yu., Feiler L. A. Protective phosphate coatings on metals. Vestnik Kuzbasskogo gosudarstvennogo tekhnicheskogo universiteta. 2020. Vol. 142. No. 6. pp. 46–50.
32. GOST 9.302–88. Unified system of corrosion and ageing protection. Metal and non-metal inorganic coatings. Control methods. Introduced: 01.01.1990.