DOI: 10.52150/2522-9117-2018-32-250-258

Palamar Dmitry Grigorovich, Junior Researcher (Engin.), , Iron and Steel Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107

Vorobei Sergey Alexandrovich., Dr.Sci. (Engin.), Senior Research Scientist, Iron and Steel Institute named after Z.I. Nekrasovof the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107; e-mail: vso54@ukr.net, ORSID 0000-0003-0119-3935

Razdobreev Valery Guriyovych, PhD (Engin.), Senior Researcher, Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107; e-mail: v_razdobreev@mail.ru

Balakhanova Tetyana Valeriyivna, PhD (Engin.), Senior Researcher, Iron and Steel Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107; e-mail: Gr_tatja@mail.ru

Investigation of the unevenness of mechanical properties along the cross-section of continuously cast billets

Abstract. The aim of the work is to study the non-uniformity of mechanical properties in the cross section of continuously cast billets of various manufacturers in Ukraine. Mechanical properties were determined by the method of measuring Brinell hardness. Mathematical relationships were developed to describe them and determine the need to take this factor into account when calculating the stress-strain state of blanks. It is established that the hardness of the surface layer of blanks, as a rule, is higher than the central zone by 0.5-7.6%. This is due to the smaller and dense dendritic structure of the surface layers. The biggest difference is observed in workpieces with a thickness of 410 mm made of steel grade 20. In workpieces made of steel grade 45, the difference in hardness of the surface layer and the central zone is 0.5- 4.7% and practically does not depend on the thickness of the workpiece in the investigated interval (135-350 mm). It is shown that in the study of the stressstrain state of the metal when rolling continuously cast billets of low-carbon steels, it is advisable to take into account the uneven distribution of mechanical properties over the cross section. For medium carbon steel blanks, this factor is optional. On the basis of literature data and the results of experimental studies performed, dependencies describing the change in strength and plastic properties in the cross section of continuously cast billets of low carbon steels are proposed. These dependencies should be used in the calculation of the stress-strain state of the metal. For medium-carbon steel blanks, this factor is optional.
Keywords: continuous-cast billet, section, stress-strain state of metal, mechanical properties, hardness

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