Volgograd State Technical University (Volgograd, Russia):

D. V. Rutskiy, Cand. Eng., Associate Prof.
N. A. Zyuban, Dr. Eng., Prof., Head of the Dept “Technology of Materials”, e-mail: tecmat@vstu.ru

Volzhsky Pipe Plant (Volzhsky, Russia):
I. V. Neklyudov, Chief Metallurgist
A. Yu. Agarkov, Leading Engineer Technologist, Steel Making and Casting Lab, Central Plant laboratory

The paper presents the results of a study of contamination of carbon steel grade D with non-metallic inclusions in samples taken at all stages of the metallurgical processing in the conditions of the electric steelmelting shop of JSC “Volzhsky Pipe Plant”. Studies have shown that the use of aluminum as a deoxidizing agent leads to the formation in steel, mainly of refractory non-deformable inclusions of corundum (Al₂O₃), which have an unfavorable shape for further pressure treatment. Outof-furnace treatment helps to reduce the contamination of steel with non-metallic inclusions, as well as the modification and globularization of corundum inclusions. Moreover, the use of aluminum as a deoxidizing agent leads to an increase in nonmetallic inclusions in a continuously cast billet. The use of calcium carbide (CaC₂) as a deoxidizing agent has a positive effect on the chemical composition of nonmetallic inclusions, leads to modification and globularization in the initial stages of smelting corundum and the production of calcium aluminates (xCaO·yAl₂O₃) based on aluminum magnesian spinel (Al₂O₃)·(MgO). The favorable form of inclusions obtained in the early stages of secondary treatment is maintained in subsequent redistribution, which leads to the creation of favorable conditions for the removal of inclusions. The use of CaC₂ as a deoxidizing agent makes it possible to obtain a continuously cast billet having a lower contamination with non-metallic inclusions.
The study has been carried out with financial support of the Russian Foundation for Basic Research in the framework of the research project No. 18-08-00050\18.

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