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Strength properties of carbon steel of railway wheel after the speed-up cooling

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Category: Geotechnical and mining mechanical engineering, machine building

Last Updated on 19 November 2016

Published on 17 November 2016

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Authors:

I.O.Vakulenko, Dr. Sc. (Tech.), Prof., Dnipropetrovsk National University of Railway Transport named after academician V.Lazaryan, Dnipro, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

О.G.Lisniak, Cand. Sc. (Tech.), Assoc. Prof., State Higher Educational Institution “National Mining University”, Dnipro, Ukraine

O.М.Perkov, Cand. Sc. (Tech.), Senior Res. Associate, Iron and Steel Institute named after Z.I.Nekrasov, NAS of Ukraine, Dnipro, Ukraine

Abstract:

Purpose. The work is directed at elaboration of softening effect of carbon steel of a railway wheel after the speed-up cooling to the different temperatures.

Methodology. Material for the research was carbon steel of a disk railway wheel with content of 0.57 % C, 0.65 % Si, 0.45 % Mn, 0.0029 % S, 0.014 % P, 0.11 % Cr. Specimens as plates 3 mm thick were exposed to heating up to the temperatures higher than Ac3, the subsequent speed-up cooling was halted after achieving certain temperatures (200–450 °C). A structure was studied with the use of electronic and light microscopes. The estimation of degree of the structure defect after the speed-up cooling was carried out with the use of method of x-ray analysis. The strength and yield stresses of carbon steel were determined under tension. Speed of deformation at mechanical tests was 10-3 s-1. The microhardness of structural constituents of steel was estimated using the apparatus a PMT-3 type.

Findings. The research results of the structural state and properties of carbon steel of a railway wheel are presented depending on the temperature of self-tempering after the irregular cooling. Within the investigated temperature interval of self-tempering, permanent soften character of carbon steel with growth of the temperature of completion of the forced cooling of wheel is conditioned by the correlation of qualitatively different processes structural transformations.

Originality. The net effect of softening the metal by reducing the degree of supersaturation of solid solution, reducing the dislocation density and coalescence of cementite particles exceeds the strengthening due to the presence of fine carbide particles in the structure.

Practical value. According to studies it is determined that in order to increase fracture toughness, the disc-rolled railway wheel can be subjected to accelerated cooling to temperatures of 300–350 оC without substantial metal embrittlement.

References/Список літератури

1. Vakulenko, І. O., Anofrіiev, V. G. and Hryshchenko, M.A., 2009. Defekty zalіznychnykh kolіs [Defects of railway wheels]. Dnipropetrovsk: Makovetskyi.

Дефекти залізничних коліс / [Вакуленко І. О., Анофрієв В. Г., Грищенко М. А. та ін.] – Дніпропетровськ: „Маковецький“, 2009. – 112с.

2. Yefremenko, V. G., Tkachenko, F. K., Kuzmin, S. O. and Kazankov, V. G., 2009. Kinetics of transformation of austenite in rail steel of M74 and 75ХГСМ type at the continuous cooling. Science and Transport Progress Bulletin of Dnipropetrovsk National University of Railway Transport named after V. Lazaryan, Vol. 29, pp. 98–201.

Кинетика превращения аустенита в рельсовых сталях марок М74 и 75ХГСМ при непрерывном охлаждении / В. Г. Ефременко, Ф. К. Ткаченко, С. О. Кузьмин, В. Г. Казанков // Вісн. Дніпропетр. нац. ун-ту залізн. трансп. ім. акад. В. Лазаряна. – 2009. – Вип. 29. – С. 198–201.

3. Vakulenko, L. І., 2010. Estimation of degree of strengthening at tempering of the hard-tempered wheel steel. Science and Transport Progress Bulletin of Dnipropetrovsk National University of Railway Transport named after V. Lazaryan, Vol. 31, pp. 259–261.

Вакуленко Л. І. Оцінка ступеня знеміцнення при відпуску загартованої колісної сталі / Л. І. Вакуленко, Ю. Л. Надеждін // Вісн. Дніпропетр. нац. ун-ту залізн. трансп. ім. акад. В. Лазаряна. – 2010. – Вип. 31. – С. 259–261.

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Большаков В. И. Атлас структур металлов и сплавов / Большаков В. И., Сухомлин Г. Д., Погребная Н. Э. – Днепропетровск: Gaudeamus, 2001. – 113 c.

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6. Vakulenko, I. A. and Bolshakov, V. I., 2008. Morfologiia struktury i deformatsionnoe uprochnenie stali [Morphology of structure and deformation work-hardening steel]. Dnipropetrovsk: Makovetskyi.

Вакуленко И. А. Морфология структуры и деформационное упрочнение стали / Вакуленко И. А., Большаков В. И. – Днепропетровск: „Маковецкий“, 2008. – 196 с.

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