Ultralow-alkalinity high-vitrification covering slag for bloom medium-high carbon steel and preparation method thereof

Abstract

The invention discloses ultralow-alkalinity high-vitrification covering slag for bloom medium-high carbon steel and a preparation method thereof, and belongs to the technical field of steelmaking metallurgy auxiliary materials. The ultralow-alkalinity high-vitrification covering slag for the bloom medium-high carbon steel is prepared from the following raw materials of, by weight, 15-35 parts of wollastonite, 15-30 parts of power plant molten coal cinder waste, 2-13 parts of quartz, 6-13 parts of albite, 2-8 parts of sodium fluoride, 1-5 parts of sodium carbonate, 6-10 parts of fluorite, 2-5 parts of magnesia powder, 1-6 parts of 390 medium-carbon graphite, 2-6 parts of high-carbon amorphous graphite, 1.5-3 parts of semi-reinforcing natural gas carbon black and 5-8 parts of sodium silicate. The ultra-low alkalinity is adopted, the vitrification rate in the slag solidification process is controlled to be high, and then the blank shell thickness and the lubricating effect in the medium-high carbon continuous casting process are guaranteed; the high viscosity is adopted, under the condition that a casting blank has certain shrinkage, molten slag is evenly guided in, solid slag film is uniform, and it is guaranteed that the surface of the casting blank is smooth; slightly high melting point and viscosity are adopted, so that the use amount of flux is reduced, the slag surface tension is improved, and the slag entrapment probability is reduced; and compound carbon blending is adopted, and then the problem of accidental carbon pickup of the casting blank is relieved by adjusting the carbon blending.

Description

technical field [0001] The invention belongs to the technical field of steelmaking and metallurgical auxiliary materials, and in particular relates to an ultra-low alkalinity and high vitrification mold powder for medium-high carbon steel in a bloom and a preparation method thereof. Background technique [0002] The medium-high carbon steel produced by the bloom is basically special-purpose steel, which has high requirements on the surface and subcutaneous quality of the billet. The shell under static pressure expands, and it is easy to stick to the wall of the crystallizer, resulting in bonding and scratches (slag grooves) on the primary shell; in addition, due to the low temperature of the liquidus line of medium and high carbon steel, the casting temperature leads to the endothermic melting effect of mold slag Deterioration, prone to defects such as thin liquid slag layer and slag entrainment. In addition, the casting speed of blooms is generally low, and it has wide ada...

AI Technical Summary

Problems solved by technology

The mold slag has low carbon content, high pre-melting ratio, is not easy to generate slag rings, and can self-heat. It is applied to high-carbon steel in square and rectangular special steel to avoid local carburization of high-carbon steel in special steel. At the same time, the fluorine content is low to avoid Erosion of nozzle slag line, but no reuse of molten cinder waste