Innovation Center for Modern Textile Technologies (Jianhu Laboratory), Shaoxing, China¹ ; Polzunov Altai State Technical University, Barnaul, Russia² ; Wuhan Textile University, Wuhan, China³

S. G. Ivanov, Dr. Eng., Leading Researcher^1,2, Leading Researcher, Hubei State Key Laboratory of Digital Textile Machinery³, e-mail: serg225582@yandex.ru

Altai State University, Barnaul, Russia
N. I. Mozgovoy, Cand. Eng., Associate Prof., Dept. of Technosphere Safety and Analytical Chemistry, e-mail: nick_3@bk.ru

Polzunov Altai State Technical University, Barnaul, Russia¹ ; Zhejiang Brilliant Refrigeration Equipment Co. Ltd., Xingchang, China²
M. A. Guryev, Cand. Eng., Associate Prof., Dept. of Mechanical Engineering Technology¹, Technical Director², e-mail: gurievma@mail.ru

Wuhan Textile University, Wuhan, China¹ ; Moscow Polytechnic University, Moscow, Russia² ; Vladimir State University named after Alexander and Nikolay Stoletovs, Vladimir, Russia³
V. B. Deev*, Dr. Eng., Prof., Faculty of Mechanical Engineering and Automation¹, Head of the Department of Welding Equipment and Technologies², Chief researcher³, e-mail: deev.vb@mail.ru

Polzunov Altai State Technical University, Barnaul, Russia¹ ; Wuhan Textile University, Wuhan, China² ; Zhejiang Pinuo Machinery Co., Ltd., Shaoxing, China³
A. M. Guryev, Dr. Eng., Head of the Dept. of Descriptive Geometry and Graphics¹, Prof., Faculty of Mechanical Engineering and Automation2, Chief researcher³, e-mail: gurievam@mail.ru

*Corresponding author.

Graphite is one of the thermodynamically stable phases in iron-carbon alloys, including steels. However, under normal conditions, carbon in steels is in a bound state in the form of iron carbide. The release of carbon in free form in steels leads to a loss of strength and performance characteristics of steels, therefore this process is considered undesirable, and in the case of critical parts, even unacceptable. If graphite is detected in the structure of critical parts of power engineering, this is a defective feature and graphitized parts must be replaced immediately to avoid accidents. It should be noted that laboratory experiments to establish all the features of graphitization have become extremely expensive and not very relevant due to the characteristics of the graphitization process: very long duration and high dependence on the temperature of the graphitization process. Therefore, scientists are forced to study the process of graphitization of steels on full-scale samples, which take into account all the many factors affecting the process of graphitization of steels. In this paper, the graphitization process of low-carbon steel 20, from which the details of the oil refining equipment were made, is studied. It was found that the graphitization process of steel 20 took place in these parts at operating temperatures of 380-420 °C and an operating time of 2,700-3,000 hours, whereas according to other authors, for graphitization of steel 20 under these conditions, the required time should be at least 25,000- 40,000 hours. It was found that one of the reasons that contributed to the acceleration of the graphitization process was a repeated short-term (no more than 2 hours) temperature increase to 620-650 °C.
This work was carried out within the framework of a state assignment in the field of scientific activity of the Ministry of Science and Higher Education of the Russian Federation (topic FZUN-2024-0004, state assignment VlSU).

1. Prikhodko O. G., Deev V. B., Kutsenko A. I., Prusov E. S. Analysis of the solidification process of castings depending on their configuration and material of the mold. CIS Iron and Steel Review. 2023.Vol. 25. pp. 31–38.
2. Prikhod’ko O. G., Deev V. B., Prusov E. S., Kutsenko A. I. Influence of thermophysical characteristics of alloy and mold material on casting solidification rate. Steel in Translation. 2020. Vol. 50, Iss. 5. pp. 296–302.
3. Deev V. B., Prusov E. S., Vdovin K. N., Bazlova T. A., Temlyantsev M. V. Influence of melting unit type on the properties of middle-carbon cast steel. ARPN Journal of Engineering and Applied Sciences. 2018. Vol. 13, No. 3. pp. 998–1001.
4. Antikayn P. A., Borisov V. E., Samarets G. N., Chesalkin A. V. Restorative heat treatment of carbon steel. Teploenergetika. 1993. No. 12. pp. 49–52.
5. Hoffman Yu. M. On the reliability of products made of steel 20, operated at high temperatures. Teploenergetika. 1992. No. 8. pp. 21–22.
6. Malyarov A. V., Kutepov S. N., Gvozdev A. E. Regularities of cementite decomposition during thermal cycling treatment of carbon steels in the pre-transformation state near the temperature A0. Collection of scientific articles of the International Scientific and Technical Conference dedicated to the 150th anniversary of the birth of Academician A. A. Baikov. 2020. pp. 98–100.
7. Begunov A. I., Osipova T. A. Destruction of steels as a result of graphitization of elements of pipelines and medium-pressure boilers. Vestnik IrGTU. 2010. No. 1 (41). pp. 257–259.
8. Kim Y. J., Bae S. W., Lim N. S. et al. Evolution of microstructure and mechanical properties of graphitized Fe–0.55C–2.3Si steel during quenching and tempering treatment. Met. Mater. Int. 2021. Vol. 27. pp. 3730–3739. DOI: 10.1007/s12540-020-00743-4
9. Phase diagrams of binary metallic systems. Handbook: in 3 volumes. General editor N. P. Lyakishev. Moscow : Mashinostroenie, 1997. 1024 p.
10. RD 10-577-03 Standard instructions for metal inspection and service life extension of the main components of boilers, turbines and pipelines of thermal power plants. 2003. 128 p.
11. Industry standard OST 34-70-690-84. Metal of steam power equipment of power plants. Methods of metallographic analysis under operating conditions. 42 p.
12. ASM Handbook: Heat Treatment. Vol. 4. ASM International, 1991. 2173 p.
13. ASM Handbook: Metallography and Microstructures. Vol. 9. ASM International, 2004. 4573 р.
14. Hayazi N. F., Shamsudin S. R., Wardan R., Sanusi M. S. M., Zainal F. F. Graphitization damage on seamless steel tube of pressurized closed-loop of steam boiler. IOP Conference Series: Materials Science and Engineering. 2019. Vol. 701. 012042. DOI: 10.1088/1757-899X/701/1/012042
15. Pérez I. U., da Silveira T. L., da Silveira T. F. et al. Graphitization in low alloy steel pressure vessels and piping. J Fail. Anal. and Preven. 2011. Vol. 11. pp. 3–9. DOI: 10.1007/s11668-010-9414-z
16. Tomotaka H., Kota S., Kaoru S., Toru H., Kazuhiro K. TTP diagrams of graphitization of creep ruptured carbon steels and 0.5Mo steel. ISIJ International. 2021. Vol. 61, Iss. 11. pp. 2822-2831. DOI: 10.2355/isijinternational.ISIJINT-2021-275
17. Kim Y. J., Park S. H. Effect of initial microstructure on graphitization behavior of Fe – 0.55 C – 2.3 Si steel. Journal of Materials Research and Technology. 2021. Vol. 15. pp. 4529-4540. DOI: 10.1016/j.jmrt.2021.10.071
18. Kim Y. J., Bae S. W., Kim S. H., Lim N. S., Park S. H. Effects of B and Ti addition and heat treatment temperature on graphitization behavior of Fe - 0.55 C - 2.3 Si steel. Journal of Materials Research and Technology. 2020. Vol. 9, Iss. 5. pp. 11189–11200. DOI: 10.1016/j.jmrt.2020.08.001
19. Foulds J. R., Viswanathan R. Graphitization of steels in elevated-temperature service. J. of Materi Eng and Perform. 2001. Vol. 10. pp. 484–492. DOI: 10.1361/105994901770344935
20. Hatakeyama T., Sawada K., Sekido K., Hara T., Kimura K. Graphitization behaviors of creepruptured 0.3% carbon steel at 673 to 773 K. ISIJ International. 2021. Vol. 61, Iss. 3. pp. 993-1001. DOI: 10.2355/isijinternational.ISIJINT-2020-575
21. Iwamoto T., Hoshino T., Matsuzaki A., Amano K. Effects of boron and nitrogen on graphitization and hardenability in 0.53 % C steels. ISIJ International. 2002. Vol. 42. pp. S77–S81. DOI: 10.2355/isijinternational.42.Suppl_S77.
22. Kim Y. J., Bae S. W., Lim N. S., Park S. H. Graphitization behavior of medium-carbon high-silicon steel and its dependence on temperature and grain size. Materials Science and Engineering: A. 2020. Vol. 785. 139392. DOI: 10.1016/j.msea.2020.139392
23. Foulds J. R., Shingledecker J. P. An updated assessment of graphitization of steels in elevated temperature service. Journal of Materials Engineering and Performance. 2015. Vol. 24. pp. 586–597. DOI: 10.1007/s11665-014-1376-y
24. Neri M. A., Colás R., Valtierra S. Effect of deformation on graphitization kinetics in high carbon steels. Journal of Materials Processing Technology. 1998. Vol. 83, Iss. 1–3. pp. 142-150. DOI: 10.1016/S0924-0136(98)00053-3
25. Yousefi M., Rajabi M., Sadegh M. Kerahroodi A. Graphitization cracks in Ck45 steel clips of turbofans. Engineering Failure Analysis. 2021. Vol. 125. 105402. DOI: 10.1016/j.engfailanal.2021.105402
26. Hatakeyama T., Sekido K., Sawada K. Prediction of graphitization behavior during long-term creep in carbon steels. ISIJ International. 2023. Vol. 63, Iss. 5. pp. 910–918. DOI: 10.2355/isij international.ISIJINT-2022-558
27. Brusco M. Logistic regression via excel spreadsheets: mechanics, model selection, and relative predictor importance. INFORMS Transactions on Education. 2022. Vol. 23, Iss. 1. pp. 1–11. DOI: 10.1287/ited.2021.0263
28. Zhang Yj., Han Jt. A study of graphitization of free-cutting steel. Met Sci Heat Treat. 2019. Vol. 60. pp. 817–819. DOI: 10.1007/s11041-019-00362-w
29. Tarasevich B. N. IR spectra of the main classes of organic compounds: reference materials. Lomonosov Moscow State University, Faculty of Chemistry, 2012. 54 p.
30. Fedyukin V. K., Smagorinskiy M. E. Thermal-cyclic treatment of metals and machine parts. Leningrad : Mashinostroenie - Leningradskoe otdelenie. 1989. 254 p.
31. Hamedi Y., Kiani-Rashid A. R., Shishegar H. R., Azaat-Pour H. R. The influence of different heat treatment cycles on controlled surface graphitization in CK45 steel. Journal of Alloys and Compounds. 2010. Vol. 492. Iss. 1–2. pp. 739–744. DOI: 10.1016/j.jallcom.2009.12.036
32. Pérez I. U., da Silveira T. L., da Silveira T. F. Graphitization in low alloy steel pressure vessels and piping. J Fail. Anal. and Preven. 2011. No. 11. pp. 3–9. DOI: 10.1007/s11668-010-9414-z
33. Guryev A. M., Voroshnin L. G., Kharaev Yu. P., Lygdenov B. D., Chernykh E. V. Cyclic thermal effect during thermal and thermochemical treatment of tool steels. Fundamentalnye problemy sovremennogo materialovedenieya. 2005. Vol. 2. No. 3. pp. 37–45.