Babachenko Oleksandr Ivanovych, Dr. Sci. (Engin.), Senior Research Scientist, Director, Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107. ORCID: 0000-0003-4710-0343. E-mail: office.isi@nas.gov.ua

Kononenko Ganna Andriivna, Dr. Sci. (Engin.), Senior Researcher, Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107. ORCID 0000-0001-7446-4105

Podolskyi Rostyslav Viacheslavovych, Junior Researcher, Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107. ORCID 0000-0002-0288-0641

Shpak Olena Adolfovna, Junior Researcher, Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107. ORCID 0000-0001-7446-4Х05

Safronova Olena Anatoliivna, Junior Researcher, Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107. ORCID 0000-0002-4032-4275

Martsinishin Viktor Viktorovych, Student, Ukrainian State University of Science and Technology, Lazariana Str., 2, Dnipro, Ukraina. ORCID 0000-0001-7446-41Х5

RESEARCH OF FEATURES OF STRUCTURE OF A RAILWAY WHEEL WITH OPERATIONAL DEFECTS

Summary. Рurpose: to study the macrostructure and microstructure, mechanical properties, chemical composition of railway products and to establish the probable cause of decommissioning. In cases of premature decommissioning of metal testing of responsible purpose, expert studies may be conducted. The purpose of expert research is to establish quality indicators of metal products and their compliance with the requirements of regulatory and technical documentation, to identify the nature, nature and causes of defects, destruction of metal products and product failures. Methods of non-destructive testing, metallographic analysis, determination of mechanical properties, chemical analysis were used. The material was a railway wheel manufactured in accordance with EN 13262: 2004+ A2: 2011 in the conditions of PJSC “INTERPIPE NTZ”, which was decommissioned due to the formation of defects on the rolling surface. Defects in the form of residual cracks in the amount of 4 pieces from  6 to 28 mm were detected on the surface of the turned part of the wheel № 140. The content of chemical elements and mechanical properties meet the requirements of standard EN 13262: 2004 + A2: 2011 for steel grade ER 8. Analysis of the macrostructure of the investigated elements (rim and disc) of the wheel showed no defects of metallurgical origin: flocs, bundles, wrapped corks and sunken, non-metallic inclusions, residues of shrinkage shells and other violations of the integrity of the metal. The macrostructure of the templates of the elements of the studied wheel has a dense and homogeneous structure. The microstructure in the wheel rim samples № 140 near the defects on the rolling surface is characterized by the presence of cracks, areas of the “white layer”. Analysis of the trajectory of crack development, pronounced texture (deformation) of the metal structure in the center of fracture in the direction of tangential stresses indicate the fatigue nature of the formation of cracks on the rolling surface.

Key words: railway wheel, mechanical properties, microstructure, non-metallic inclusions, non-destructive testing.

For citation: Babachenko O. I., Kononenko G. A., Podolskyi R. V., Shpak O. A, Safronova O. A, Martsinishin V. V. Doslidzhennya osoblyvostey struktury zaliznychnoho kolesa z ekspluatatsiynymy defektamy [Research of features of structure of a railway wheel with operational defects]. Fundamental’nye i prikladnye problemy černoj metallurgii [Fundamental and applied problems of ferrous metallurgy], 2021, 35, 310-322. (In Ukrainian).

DOI: 10.52150/2522-9117-2021-35-310-322

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