SLAG-FORMING MIXTURE FOR CONTINUOUS CASTING OF RAIL STEEL Russian patent published in 2011 - IPC B22D11/111 

FIELD: chemistry.

SUBSTANCE: invention relates to ferrous metallurgy, specifically, to compositions of slag-forming mixtures used in continuous casting of steel, in particular, in production of rails. The slag-forming mixture is produced by mixing of amorphous graphite, a fluorspar concentrate and materials containing silicon, aluminium and alkaline metals oxides, such as feldspar mixture (FSM), soda ash, finely ground quartzite and cement. Components are taken at the following ratio, wt %: amorphous graphite 18-22, fluorspar concentrate 11-15, FSM 13-38, soda ash 1-15, finely ground quartzite 1-15, cement - the rest. The mixture has the basic capacity of (CaO/SiO₂) 0.6-1.0 and the following chemical composition, wt %: C 12.0-18.0, CaO 22.0-28.0, SiO₂ 28.0-37.0, Al₂O₃ 4.5-10.0 F 4.5-9.0, (Na⁺+K⁺) 3.0-11.0.

EFFECT: increased assimilating capacity of the mixture relative to non-metal inclusions, increased quality of steel due to improved macrostructure, less rejected stocks because of surface defects due to improved lubrication of the crystalliser by a melt slag-forming mixture.

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