Volgograd State Technical University, Volgograd, Russia

M. V. Kirilichev, Head of Laboratory, Dept. of Materials Technology, e-mail: tecmat@vstu.ru
N. A. Zyuban, Dr. Eng., Prof., Dept. of Materials Technology, e-mail: tecmat49@vstu.ru
D. V. Rutskiy, Cand. Eng., Associate Prof., Head of Dept. of Materials Technology, e-mail: drutskii@vstu.ru

JSC “Volzhsky Pipe Plant“, Volzhsky, Russia
M. Yu. Chubukov, Cand. Eng., Head of the Central Plant Laboratory, e-mail: mikhail.chubukov@tmk-group.com

Problems of chemical heterogeneity today are relevant and significant because development of mirosegregation processes is accompanied by the formation of zonal segregation in various parts of the ingot and continuously cast billet (CCB), which leads to a decrease in the quality of the metal and the acceptance characteristics of the billets. Particular difficulties are caused by the presence of mirosegregation heterogeneity in the CCB, taking into account the peculiarities of the redistribution of impurities and their solubility under conditions of accelerated cooling during the movement of the workpiece in the crystallizer. In this work, dendrite segregation was studied in round cast iron steel 26KhGMFA. It was found that the elements molybdenum, chromium vanadium, and manganese are most prone to mirosegregation heterogeneity due to the peculiarities of their solubility in the melt. According to the degree of segregation, these elements are in the following sequence: Mo, Mn, Cr, V, Si. The values of the CCB segregation coefficients were compared with similar indicators for an ingot weighing 24.2 t of 38KhN3MFA steel. It was found that the segregation coefficients in the ingot are 1.2-1.6 times higher than in the continuous casting process, which is due to the peculi aritiesof thermal processes at the end of solidification of the ingot. The results obtained coincide with those of other researchers. To reduce the manifestations of mirosegregation heterogeneity, it is necessary to optimize the cooling conditions of the CCB, using rationally shaped crystallizers, and also use the introduction of inoculants into the melt.
The reported study was funded by Volgograd State Technical University according to the research project No. 6/469-22.

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