ROLE OF HIGH-TEMPERATURE TEMPERING IN FORMATION OF STRUCTURAL-PHASE STATES OF PLASMA-DEPOSITED MOLYBDENUM HIGH-SPEED STEEL

The technology of plasma surfacing in nitrogen on 30HGSA grade steel with a powder wire of the MoCrCoC system with a diameter of 4 mm formed a deposited layer with a thickness of approximately 9 ‒ 10 mm Argon of the highest grade was used as the plasma-forming gas. The structural and phase states and defective substructure of the surface of a plasma-deposited layer in a nitrogen medium with high-speed molybdenum steel on a substrate subjected to double tempering at a temperature of 560 ‒ 580 °C for 1 hour have been studied by methods of modern physical materials science. It is shown that the deposited layer has a polycrystalline structure and contains layers of eutectic. The formation of a multiphase structure in the deposited layer was revealed, represented by an α-phase (solid solution based on the BCC crystal lattice Fe), a γ-phase (solid solution based on the FCC crystal lattice Fe), carbides of complex composition Me₂₃C₆ and Me₆C, iron carbides Fe₃C and chromium Cr₃C₂. It was established that tempering of the deposited layer does not lead to a change in the morphology of the structure formed by grains of eutectic and a solid solution based on α-iron (BCC crystal lattice). The main phases are α-Fe (85 wt. %) and carbides of complex composition Me₂₃C₆ (9 wt. %) and Me₆C (6 wt. %) forming eutectic grains. It has been established that the tempering of the deposited layer is accompanied by the pre-transformation of residual austenite with the formation of nanoscale particles of iron and chromium carbides along the boundaries of martensite crystals. Microcracks have been identified along the interfacial interfaces and in the volume of the plates of the carbide phase of eutectic grains, which can initiate the destruction of the deposited layer material during operation.

1. Emelyushin A.N., Petrochenko E.V., Nefed'ev S.P. Investigation of the structure and impact-abrasive wear resistance of Fe‒C‒Cr‒Mn‒Si system coatings additionally doped with nitrogen. Svarochnoe proizvodstvo. 2011;10:18‒22. (In Russ.).

2. Nefed'ev S.P., Emelyushin A.N. Plasma surface hardening. Staryi Oskol: TNT, 2021;156. (In Russ.).

3. Hacisalihoglu I., Yildiz F., Alsaran A. Wear performance of different nitride-based coatings on plasma nitrided AISI M2 tool steel in dry and lubricated conditions. Wear. 2017;384-385:159–168.

4. Ivanov Yu.F., Gromov V.E., Potekaev A.I., Guseva T.P., Chapaikin A.S., Vashchuk E.S., Romanov D.A. Structure and properties of R18U surfacing of high-speed steel after its high tem-pering. Russian Physics Journal. 2023;66(7);731‒739. https://doi.org/10.1007/s11182-023-02999-w

5. Emelyushin A.N., Petrochenko E.V., Nefed′ev S.P. Inverstigation of the structure and impact-abrasive resistance of coatings of the Fe‒C‒Cr‒Mn‒Si system, additionally alloyed with nitro-gen. Welding International. 2013;27(2):150‒153.

6. Kravchenko I.N., Kartsev S.V., Kolomeichenko A.V. et al. Metallurgical Features of Plasma Sur-facing with Powder Hard Alloy with Addition of Aluminum Powder. Metallurgist. 2021;64(9-10):1077‒1085. https://doi.org/10.1007/s11015-021-01089-x

7. Ivanov Yu.F., Gromov V.E., Yuryev A.B., Minenko S.S., Semin A.P., Chapaikin A.S. Structure, Phase Composition, and Surface Properties of R2M9 High-Speed Steel. Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques. 2024;18(6):1395–1400.

8. Kremnev L.S., Onegina A.K., Vinogradova L.A. Peculiarities of transformations, structure and properties of molybdenum high-speed steels. Metallovedenie i termicheskaya obrabotka metal-lov. 2009;12(654):13‒19. (In Russ.). EDN: KZSBKP

9. Kremnev L.S. The theory of alloying and the creation of heat-resistant tool steels and alloys based on it. MiTOM. 2008;11:18‒28. (In Russ.). EDN: KVXKKF

10. Rakhadilov B.K., Wieleba W., Kylyshkanov M.K. et al. Structure and phase composition of high - speed steels. Bulletin of the Karaganda University. Physics Series. 2020;2(98):83‒92. https://doi.org/10.31489/2020Ph2/83-92

11. Ivanov Yu.F. Structural and phase transfor-mations in a number of steels under static and dynamic heat treatment conditions. Avtoref. dis. dokt. f.-m. nauk. Moscow, 2002:41. (In Russ.).

12. Rotshtein V.P., Proskurovskii D.I., Ozur G.E., Ivanov Yu.F. Modification of the surface of me-tallic materials by low-energy high-current elec-tron beams. Novosibirsk: SO RAN Nauka, 2019:348. (In Russ.).

13. Koval' N.N., IvanovYu.F. ed. Evolution of the structure of the surface layer of steel subjected to electron-ion-plasma treatment. Tomsk: NTL, 2016:298. (In Russ.).

14. Pout Dzh., Fot G., Dzhekobson D. ed. Modifica-tion and doping of the surface by laser, ion and electron beams. Moscow: Mashinostroenie, 1987:424. (In Russ.).

15. Ivanov Yu.F., Gromov V.E., Minenko S.S., Guseva T.P., Chapaikin A.S., Semin A.P. Struc-ture and properties of the surface layer obtained by plasma surfacing from high-entropy molyb-denum high-speed steel, after complex pro-cessing. Materialovedenie. 2025;6:15‒23. (In Russ.).

16. Gromov V.E., Ivanov Yu.F., Yuryev A.B., Minenkо S.S., Konovalov S.V. Modification of transition zone structure of high-speed steel sur-facing ‒ substrate by electron-beam treatment. Bulletin of the Siberian State Industrial Universi-ty. 2025;1(51):43‒50.

17. Paikin A.G., Shulov V.A., Engel'ko V.I. etc. Cratering on the surface of parts made of heat-resistant steel 15X16K5N2MVFAV-Sh when ir-radiated with high-current pulsed electron beams. Uprochnyayushchie tekhnologii i pokrytiya. 2006;10:9−14. (In Russ.). EDN: HVMOZZ.

18. Shulov V.A., Paikin A.G., Belov A.B. etc. Modification of the surface of parts made of heat-resistant steels by high-current pulsed electron beams. Fizika i khimiya obrabotki materialov. 2005;2:61−70. (In Russ.). EDN: HSGMVF

19. Fedorov S., Sharipov Ja., Abrorov A. Increasing the surface stability of the cutting tool through complex machining. Journal of Physics: Confer-ence Series: II International Scientific Confer-ence on Metrological Support of Innovative Technologies (ICMSIT II-2021), St. Petersburg, 2021;1889:22079. https://doi.org/10.1088/1742-6596/1889/2/022079

20. Egerton F.R. Physical Principles of Electron Mi-croscopy. Basel: Springer International Publish-ing, 2016:196.

21. Kumar C.S.S.R. Transmission Electron Micros-copy. Characterization of Nanomaterials. New York: Springer, 2014:717.

22. Carter C.B., Williams D.B. Transmission Elec-tron Microscopy. Berlin: Springer International Publishing, 2016:518.