Bryansk State Technical University, Bryansk, Russia

R. A. Bogdanov, Cand. Eng., Associate Prof., Dept. of Turbine construction, electric and heat power engineering, e-mail: lpim-bra@yandex.ru

An analytical review of statistical data for the three-year period 2020-2022 between the variable values of impact strength and the chemical composition of 20GL cast steel smelted in electric arc furnaces for freight car castings “Side frame” and “Spring beam” was carried out. The results of such analysis showed a high percentage of defects (18 %) in terms of impact strength KCV-60, and also displayed possibility of assessing the joint effect (S+P) and each chemical element separately on a variety of impact strength indicators. viscosity KCV-60. Optical microscopy contributed to the implementation of statistical and metallographic studies of non-metallic inclusions, taking into account the Vestra Image System program according to GOST 1778-70 (method L) based on the measurement of average diameters of sulfides and point oxides on samples of low-alloy cast steel 20GL with different impact strength KCV-60. To understand the difference in the amount of the average diameter of sulfides and point oxides in the studied samples with different impact strength KCV-60, the 20GL liquid steel smelting passport in the main electric arc furnaces was examined in details. Images of the microstructure with distribution of various elements on samples with variable impact strength KCV-60 were obtained using an Osiris transmission/scanning electron microscope equipped with a high-angle ring dark-field detector (VKTD) and an X-ray energy-dispersion spectrometer Super X. Calculation of economic damage only for rejects related to the impact strength of KCV-60 are presented.

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