STRUCTURE AND PROPERTIES OF THE SURFACE OF HIGH-CHROMIUM STEELS MODIFIED WITH AN INTENSE PULSED ELECTRON BEAM

The work is focused on the identification and the analysis of regularities in formation of nanostructured, multiphase surface layers in high-chromium steels 12Cr18Ni10T and 20Cr13 subjected to irradiation with an intense pulsed electron beam (installation “SOLO”). A  thermodynamic analysis of Fe – Cr – C system was carried out. It is shown that carbon-doping of Fe – Cr alloys leads to a significant change in the structural-phase state and has a determining effect on existence regions of carbides Me23С6 , Me7 С3 , Me3 С2 , and Me3 С with α- and γ-phases. Numerical calculations of the temperature field formed in the surface layer of steel during the irradiation with an electron beam were carried out. It is shown that at a beam energy density of 10  J/cm2 , regardless of the pulse duration of the electron beam (50  –  200  ms), the maximum temperature reached at the sample surface by the end of the pulse is below the melting point of steel. At an energy density of the electron beam (20  –  30) J/cm2 and pulse duration of 50  µs the maximum temperature of irradiated surface is equal to the boiling point of steel; at a pulse duration of 200  µs it reaches or exceeds the melting point of steel. The structure, mechanical and tribological properties of surface layer of the samples of high chromium steels 12Cr18Ni10T and 20Ni13 formed under the irradiation with an intense pulsed electron beam were studied. It is established that the electron-beam treatment of steel in the melting mode and the subsequent high-speed crystallization is accompanied by dissolution of particles of the initial carbide phase of the composition Me23С6 ((Cr,  Fe)23C6 ), saturation of the crystalline lattice of the surface layer with chromium atoms, formation of cells of the dendritic crystallization of submicron sizes, and release of nanosized particles of titanium carbide and chromium carbide. Together, this made it possible to increase (relative to the initial state) the strength and tribological properties of the studied materials. For steel 12Cr18Ni10Т, an increase in the hardness of the surface layer by 1.5  times, the wear resistance by 1.5 times, and a decrease in the friction coefficient by 1.6 times are revealed. For steel 20Cr13, an increase in the microhardness by 1.5 times, the wear resistance by 3.2 times, and a decrease in the friction coefficient by 2.3 times are revealed.

high-chromium stainless steel, state diagram, intense pulsed electron beam, structure, phase composition, microhardness, wear resistance, friction coefficient

1. Berlin E.V., Koval’ N.N., Seidman L.A. Plazmennaya khimikotermicheskaya obrabotka poverkhnosti stal’nykh detalei [Plasma chemical-thermal treatment of the surface of steel parts]. Moscow: Tekhnosfera, 2012, 464 p. (In Russ.).

2. Budilov V.V., Koval’ N.N., Kireev R.M., Ramazanov K.N. Integrirovannye metody obrabotki konstruktsionnykh i instrumental’nykh materialov s ispol’zovaniem tleyushchikh i vakuumno-dugovykh razryadov [Integrated methods for processing structural and tool materials from glow and vacuum arc discharges]. Mukhin V.S. ed. Moscow: Mashinostroenie, 2013, 313 p. (In Russ.).

3. Poate J.M., Foti G., Jacobson D.C. Surface modification and alloying by laser, ion and electron beams. New York, London: Plenum Press, 1983, 424 p.

4. Ion implantation and beam processing. Williams J.S., Poate J.M. eds. Sydnee, New York: Academicpress, 1984, 358 p.

5. Gribkov V.A., Grigor’ev F.I., Kalin B.A., Yakushin V.P. Perspektivnye radiatsionno-puchkovye tekhnologii obrabotki metallov [Perspective radiation-beam technologies of metal processing]. Moscow: Kruglyi stol, 2001, 528 p. (In Russ.).

6. Uglov V.V., Cherenda N.N., Anishchik V.M., Astashinskii V.M., Kvasov N.T. Modifikatsiya materialov kompressionnymi plazmennymi potokami [Modification of materials by compression plasma streams]. Minsk: izd. BGU, 2013, 248 p. (In Russ.).

7. Rotshtein V., Ivanov Yu., Markov A. Surface treatment of materials with low-energy, high-current electron beams. Chapter 6 in Book “Materials surface processing by directed energy techniques”. Y.  Pauleau Ed. Elsevier, 2006, pp. 205–240.

8. Shulov V.A., Paikin A.G., Novikov A.S. etc. Sil’notochnye elektronnye impul’snye puchki dlya aviatsionnogo dvigatelestroeniya [High-current pulsed electron beams for aircraft engine building]. Shulov  V.A., Novikov A.S., Engel’ko V.I. eds. Moscow: Dipak, 2012, 292 p. (In Russ.).

9. Sorokin V.G., Volosnikova A.V., Vyatkin S.A. etc. Marochnik stalei i splavov [Grade guide of steels and alloys]. Sorokin V.G. ed. Moscow: Mashinostroenie, 1989, 640 p. (In Russ.).

10. Grigoriev S.V., Devjatkov V.N., Koval N.N., Teresov A.D. The automated installation for surface modification of metal and ceramic-metal materials and products by intensive pulse sub-millisecond electron beam. In: Proc. 9th Intern. Conf. on Modification of Materials with Particle Beams and Plasma Flows. Tomsk, 2008, pp.  19–22.

11. Abzaev Yu.A., Sarkisov Yu.S., Klopotov A.A., Klopotov V.D., Afanas’ev D.A. Full-profile x-ray structural analysis of clinker mineral C4AF. Vestnik TGASU. 2012, no. 4, pp. 200–209. (In Russ.).

12. Lyakishev N.P. Diagrammy sostoyaniya dvoinykh metallicheskikh sistem. V 3-kh t. T. 1 – 3 [Diagrams of the state of double metal systems. In 3 vols., vol. 1 – 3]. Moscow: Mashinostroenie, 1996  –  2000. (In Russ.).

13. Goldschmidt H.J. Interstitial alloys. London: Butterworths, 1967, 424 p.

14. Kubaschewski O. Iron-binary phase diagrams. Berlin-HeidelbergNew York: Springer-Verlag, 1982, 184 p.

15. Ohmori Y., Sugisawa S. The precipitation of carbide during tempering of high carbon martensite. Trans. Jap. Inst. Met. 1971, vol. 12, no. 3, pp. 170–178.

16. Jack К.Н., Wild S. Nature of χ-carbide and its possible occurrence in steels. Nature. 1966, vol. 212, no. 5059, pp. 248–250.

17. Barabash O.M., Koval’ Yu.N. Kristallicheskaya struktura metallov. Spravochnik [Crystalline structure of metals. Directory]. Kiev: Naukova dumka, 1986, 598 p. (In Russ.).

18. Belous M.V., Cherepin V.T., Vasil’ev M.A. Prevrashcheniya pri otpuske stali [Transformations at tempering of steel]. Moscow: Metallurgiya, 1973, 232 p. (In Russ.).

19. Lee B.J. Thermodynamic calculations in stainless steels alloy systems. Korean Inst. Met. 1995, vol. 33, no. 3, pp. 766–775.

20. Durand-Charre M. Microstructure of steels and cast irons. Berlin, Heidelberg: Springer, 2004.

21. Jellinghaus W., Keller H. On the iron-chromium-carbon system and distribution of chromium between ferrite and special carbides. Arch. Eisenhüttenwesen. 1972, vol. 43, no. 4, pp. 319–328. (In Germ.)

22. Kundrat D.M., Chochol M., Elliott J.F. Phase relationships in the Fe–Cr–C system at solidification temperatures. Met. Trans. 1985, vol. 15B, no. 1-4, pp. 663–676.

23. Samarskii A.A. Vvedenie v chislennye metody [Introduction to numerical methods]. Moscow: Nauka, 1997, 271 p. (In Russ.).

24. Evolyutsiya struktury poverkhnostnogo sloya stali, podvergnutoi elektronno-ionno-plazmennym metodam obrabotki [Evolution of the structure of the surface layer of steel subjected to electron-ionplasma processing methods]. Koval’N.N., Ivanov Yu.F. eds. Tomsk: Izd-vo NTL, 2016, 303 p. (In Russ.).

25. Ivanov Y., Krysina O., Petrikova E., Ivanova O., Ikonnikova I., Rygina M. Numerical simulation of thermal processes involved in surface alloying of aluminum with titanium by an intense pulsed electron beam. Key Engineering Materials. 2016, vol. 683, no. 2, pp. 569–575.

26. Babichev A.P., Babushkina N.A., Bratkovskii A.M. etc. Fizicheskie velichiny: Spravochnik [Physical Values: Handbook]. Grigor’ev E.E., Meilikhov I.S. eds. Moscow: Energoatomizdat, 1991, 1232 p. (In Russ.).