Influence of Conditions of Low-Alloy Bainite Grade Steel Cooling on the Dendritic Structure Parameters and Sphericity of Granular Bainite
DOI:
https://doi.org/10.15407/scine20.06.038Keywords:
bainite, railway rail, dendrite, sphericity, dependence, cooling rateAbstract
Introduction. Crystallization of metals and alloys typically results in the formation of branched dendritic crystals.
Problem Statement. Understanding how crystallization conditions affect the formation of the primary dendritic structure in carbon steels is crucial to comprehending the overall process of structure formation.
Purpose. This study aims to investigate the effect of varying cooling rates across the cross section of a bainite steel ingot (composition: 0.378% C, 1.02% Si, 1.38% Mn, 0.77% Cr, 0.192% Mo, 0.095% V) on the primary dendritic structure, dispersion, and sphericity of the structural components.
Materials and Methods. Metallographic analysis of the steel samples has been made with the use of Neophot 32 and Axiovert 200 M MAT light microscopes. Microstructure and chemical heterogeneity have been analyzed with a 2—3% alcoholic nitric acid (HNO3) solution and an aqueous solution derived from the reaction between trinitrophenol (picric acid) and sodium hydroxide (NaOH). The dimensions of the primary dendritic structure and final structure have been measured by the imageJ software. Brinell hardness tests have been performed on a TB5004 testing machine. Specialized software such as CalPhad and Qform has been employed for further analysis.
Results. Microstructural analysis has shown that as the density of the dendritic structure varies across the cross section of the ingot, there is a corresponding change in sphericity. Sphericity, defined as the ratio of the maximum to minimum diagonals of granular bainite, ranges from 0.1539 to 0.3673. Additionally, the lamellae of granular bainite grow approximately 2.4 times as the cooling rate decreases across the cross section of the billet, from 60 оC/min to 7 оC/min.
Conclusions. The study has established an inverse relationship between the density of the dendritic structure and the sphericity of the final granular bainite structure. The dispersion of structural components is promising for enhancing the overall mechanical properties, including both strength and plasticity.
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Babachenko, O. I., Domina, K. H., Kononenko, H. A., Dement’yeva, Zh. A., Podol’s’kyy, R. V., Safronova, O. A. (2021). Influence of Cooling Rate at Hardening of Continuous Casting Blank on Parameters of Dendritic Structure of Carbon Steel with 0.54% C. Metallofiz. Noveishie Tekhnol., 43(11), 1537—1551. https://doi.org/10.15407/mfint.43.11.1537 [in Ukrainian].
Papapetrou, A. (1935). Untersuchungen über dendritisches Wachstum von Kristallen. Zeitschrift für Kristallographie, 92(1), 89—129 [in Germany] https://doi.org/10.1524/zkri.1935.92.1.89.
Shalin, R. E., Svetlov, I. L., Kachanov, E. B., Toloraiya, V. N., Gavrilin, O. S. (1977). Single-crystals of nickel heat-resistant alloys. Moscow [in Russian].
Grankin, S. S. (2008). Study of the temperature gradient at the crystallization front of single crystals of Ni—W-alloys. Problems of atomic science and technology. Series: Vakuum, pure materials, superconductors, 17(1), 162—165 [in Russian].
Smirnov, A. N., Pilyushenko, V. L., Minaev, A. A., Molot, S. V., Belobrov, Yu. N. (2002). Сontinious casting processes. Donetsk [in Russian].
Sladkosheev, V. T., Axtyrskij, V. I., Potanin, R. V. (1963). The quality of steel during continuous casting. Moscow [in Russian].
Chizhikov, A. I., Perminov, V. P., Ioximovich, V. E. Girskij, V. E., Morozenskij, L. I., Grigorev, L. F. (1970). Сontinuous casting of steel into large section billets. Moscow [in Russian].
Smirnov, E. N. (2001). Properties and structure of billets made of continuously cast metal for the production of rolled products for critical purposes. Metal and casting of Ukraine, 3—4, 17—20 [in Russian].
Smirnov, A. N., Kuberskij, S. V., Shtefan, E. V. (2011). Continuous casting of steel. Donetsk [in Russian].
Babachenko, O. I., Kononenko, G. A., Podolskyi, R. V. (2021). Development of a model for calculating changes in K76F rail steel temperature to determine the heat treatment parameters. Science and Innovation, 17(4), 25—32. https://doi. org/10.15407/scine17.04.025
Babachenko, O. I., Kononenko, G. A., Podolskyi, R. V., Safronova, O. А. (2021). Steel for railroad rails with improved operating properties. Materials Science, 56(6), 814—819. https://doi.org/10.1007/s11003-021-00499-1
Lutsenko, V. A., Parusov, E. V., Golubenko, T. N., Lutsenko, O. V. (2019). Energy effective mode of softening heat treatment of silicon-manganese steel. Chernye Metally, 11, 31—35.
Parusov, E. V., Lutsenko, V. A., Chuiko, I. N., Parusov, O. V. (2020). Influence of chemical composition and cooling parameters on kinetics of austenite decomposition in high-carbon steels. Chernye Metally, 9, 39—41.
Pirozhkova, V. P., Yatsenko, M. Yu., Lunev, V. V., Grishchenko, S. G. (2012). Atlas of microstructures of non-metallic inclusions. Zaporizhzhia [in Russian].
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