STRUCTURE OF HYPEREUTECTOID STEEL RAILS REVEALED BY TRANSMISSION ELECTRON MICROSCOPY

The structure, phase composition, and dislocation substructure of pearlite colonies of lamellar morphology of metal chips of rails of the DT400IK category made of hypereutectoid steel at a depth of 10 mm from the rolling surface after passing a tonnage of 175.9 million tons on the East Siberian Railway has been studied. The structure analysis was performed at several structural-scale levels (macro-, micro-, submicro- and nanoscale levels). It is shown that perlite colonies are bent at the macroscopic level, the presence of perlite colonies with destroyed cementite plates in steel was revealed at the microlevel, the phenomenon of fragmentation of ferrite plates of pearlite colonies was noted at the submicroscopic level, and fragmentation of cementite plates at the nanoscale level. Nanoscale (10 ‒ 15 nm) cementite particles are observed in the volume of ferrite plates, which should be attributed to tertiary cementite formed during the decomposition of a solid solution based on α-iron. They are located on the dislocation lines. It is noted that the dislocation substructure is observed only in ferrite plates. It is represented by chaotically distributed dislocations, dislocations forming clusters, and a mesh dislocation substructure. It is shown that the steel under study is characterized by the presence of internal stress fields having a purely elastic character. The sources of stress fields are intra- and interphase boundaries (boundaries between colonies of perlite and a certain set of plates within one colony, boundaries between plates of ferrite and cementite). The identified sources of internal stress fields will lead to the formation of microcracks, which in turn contribute to the premature destruction of the rail metal during operation.

1. Bai W., Zhou L., Wang P., Hu Y., Wang W., Ding H., Han Z., Xu X., Zhu M. Damage be-havior of heavy-haul rail steels used from the mild conditions to harsh conditions. Wear. 2022;496-497:204290. https://doi.org/10.1016/j.wear.2022.204290

2. Hu Y., Zhou L., Ding H.H., Lewis R., Liu Q.Y., Guo J., Wang W.J. Microstructure evolution of railway pearlitic wheel steels under rolling-sliding contact loading. Tribology International. 2021;154:106685. https://doi.org/10.1016/j.triboint.2020.106685

3. Zhou L., Bai W., Han Z., Wang W., Hu Yu., Ding H., Lewis R., Meli E., Liu Q., Guo J. Comparison of the damage and microstructure evolution of eutectoid and hypereutectoid rail steels under a rolling-sliding contact. Wear. 2022;492-493:204233. https://doi.org/10.1016/j.wear.2021.204233

4. Zhou L. Ding H., Han Z., Chen Ch., Liu Q., Guo J., Wang W. Study of rolling-sliding contact damage and tribo-chemical behaviour of wheel-rail materials at low temperatures. Engineering. Failure Analysis. 2022;134:106077.

5. https://doi.org/10.1016/j.engfailanal.2022.106077

6. Ma L., Guo J., Liu Q.Y., Wang W.J. Fatigue crack growth and damage characteristics of high-speed rail at low ambient temperature Engineering. Failure Analysis. 2017;82:802–815. https://doi.org/10.1016/j.engfailanal.2017.07.026

7. Mojumder S., Mishra K., Singh K., Qiu C., Mutton P., Singh A. Effect of track curvature on the microstructure evolution and cracking in the longitudinal section of lower gauge corner flow lips formed in rails. Engineering. Failure Analysis. 2022;135 (1-2):106177. https://doi.org/10.1016/j.engfailanal.2022.106177

8. Wen J., Marteau J., Bouvier S., Risbet M., Cristofari F., Secorde P. Comparison of microstructure changes induced in two pearlitic rail steels subjected to a full-scale wheel/rail contact rig test. Wear. 2020;456-457:203354. https://doi.org/10.1016/j.wear.2020.203354

9. Wang J., Chen Xi., Li X., Wu Y. Influence of heavy haul railway curve parameters on rail wear. Engineering. Failure Analysis. 2015;57(2):511–520. https://doi.org/10.1016/j.engfailanal.2015.08.021

10. Rong K., Xiao Ye., Shen M., Zhao H., Wang W-J., Xiong G. Influence of ambient humidity on the adhesion and damage behavior of wheel-rail interface under hot weather condition Wear. 2021;486–487:204091. https://doi.org/10.1016/j.wear.2021.204091

11. Tushinskii L.I. Structural theory of structural strength of materials. Novosibirsk: NGTU. 2004:399. (In Russ.).

12. Schastlivtsev V.M., Medvedeva N.I., Kraposhin V.S., Talis A.L., Kar'kina L.E., Kar'kin A.R., Kuznetsov A.R., Kabanova I.G., Yakovleva I.L., Mirzaev D.A., Tabatchikova T.I., Voronin V.I, Khlebnikova Yu.V., Okishev K.Yu., Maratkanova A.N. Cementite in carbon steels. Ekaterinburg: Izdatel'stvo UMTs UPI. 2017:380. (In Russ.).

13. Panin V.E. Аctual problems of physical me-somechanics of nonlinear multilevel hierarchically organized systems. Fizicheskaya mezomekhanika. 2014;17(6):5‒6. In Russ.).

14. Carter C.B., Williams D.B. Transmission Electron Microscopy. Berlin: Springer. 2016:618.

15. Egerton F.R. Physical Principles of Electron Microscopy. Basel: Springer. 2016:575.

16. Kumar C.S.S.R. Transmission Electron Mi-croscopy Characterization of Nanjmaterials. New York: Springer. 2014:492.

17. Shchastyantsev V.M., Mirzaev D.A., Ya-kovleva I.L., Okishev K.Yu., Tabatchikova T.I., Khlebnikova Yu.V. Perlite in carbon steel. Ekaterinburg: Izd-vo IFM UrO RAN, 2006:312. (In Russ.).

18. Zhengming Sun, Peigen Zhang, Wei Liu, Wei He. Fundamentals of Materials Science. From Basic Theories to Critical Properties. Singa-pore: Springer Nature Singapore Pte Ltd. 2025:654

19. Popova N.A., Gromov V.E., Ivanov Yu.F., Porfir'ev M.A., Nikonenko E.L., Shlyarova Yu.A. The influence of long-term operation on the structural-phase state of hypereutectoid rail steel. Materialovedenie. 2023;10:17–28. (In Russ.).

20. Gromov V.Е., Ivanov Y.F., Porfiriev M.A., Shliarova Yu.A. Evolution of Cementite Substructure of Rails from Hypereutectoid Steel during Operation. Metals. 2023;13(10):1688. https://doi.org/10.3390/met13101688

21. Smirnov A.N. ed. Mesmerized by Metals. Kemerovo: Sibirskaya izdatel'skaya firma. 2025:284. (In Russ.).

22. Gleser A.M., Kozlov E.V., Koneva N.A., Popova N.A., Kurzina I.A. Plastic Defor-mation of Nanostructured Materials. CRC Press, Taylor & Francis Group, Boca Raton, London, New York. 2017:321.

23. Popova N.A., Gromov V.E., Nikonenko E.L., Trishkina L.I., Cherkasova T.V., Solov'eva Yu.V., Shlyarova Yu.A., Peregudov O.A. Strengthening mechanisms in metals and alloys. Novokuznetsk: Poligrafist. 2024:133. (In Russ.).