National University of Science and Technology “MISiS” (Moscow, Russia):

Tursunov N. K., Post-Graduate, e-mail: u_nadir@mail.ru
Semin A. E., Dr. Eng., Prof., Deputy Head of the Chair “Metallurgy of Steel and Ferroalloys”, e-mail: asemin2007@yandex.ru

Casting and Mechanical plant (Tashkent, Uzbekistan):
Sanokulov E. A., Director

Abstract: Processes of steel dephosphoration and desulphurization with the use of solid slag-forming mixtures are carried out in coreless induction furnaces with a capacity of 6 tones, and reducing of the height of metal meniscus in the bath by raising the level of the metal has been occurred. 20GL steel has been used as the test metal. The authors obtained the new quantitative relationships that made the base of technological instructions for the production of 20GL steel; these relationships reflect the effect of temperature on the process of dephosphoration. The influence of metal holding under slag in the induction crucible furnace on the final sulfur content in the metal was established. In order to increase operational reliability, improvement of the mechanical properties and modification of non-metallic inclusions, the steel in the ladle was treated with Al, SiCa, REM. The results of the study are compared with ordinary melting without REM. It is shown that the melts processed by rare earth metals has a higher degree of desulphurization. The results of semi-industrial melting allowed to manufacture the metal with essentially lower sulfur content (up to 0.004 %), oxygen content (up to 0.0021 %) and nonmetallic inclusions, as well as to provide high quality of finished products in comparison with the existing technology. Usage of rare earth metals in smelting of 20GL steel also allowet to improve macro- and microstructure and mechanical properties.

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