CS259730B1 - Casting agent for the treatment of cast steel level - Google Patents

Abstract

The subject of the solution is a casting agent for treating the surface of steel during casting. The essence of the solution is that the casting agent, in addition to the usual raw materials, also contains 0.1 to 10% by weight of mineral substances crystallizing in a monoclinic system with a tabular habit, i.e. e.g. mica.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting composition for the treatment of steel casting levels.

For the treatment of the steel level, casting means made either of pure raw materials or of waste, or alternatively a combination of both, have been used. The disadvantage of casting compositions using waste materials is the frequent fluctuation in both the chemical composition and in the properties of use during casting. Another drawback is the fact that the incidence of waste raw materials is irregular, causing considerable difficulties for producers and consumers alike. The shelf life of suitable waste materials is also difficult, as long-term storage changes their utility values.

The production of casting compositions from pure raw materials is more advantageous, as the variation of the chemical composition and thus the utility properties is minimized. However, here too, there are some drawbacks, for example, that the carbon content must be artificially replenished by graphitic carbon. The carbon in the casting agent slows the melting and creates certain specific properties of the agent in the agent-molten slag transition zone. For some steels, carbon is inadmissible in the casting agent, as it could switch to steels and change their chemical composition. Carbon is therefore needed in the casting agent, but on the other hand harmful.

The above-mentioned disadvantages of the prior art casting compositions are overcome by the casting composition according to the invention, which comprises, in addition to silicon, aluminum, calcium, alkali, fluoride and carbon, 0.1 to 10% by weight of monoclinic crystalline minerals tabular habit, ie mica, talc or pyrophyllite.

An advantage of the casting composition according to the invention is the main effect of minerals, i.e. mica, talc and pyrophyllite, which in the mixture substantially improve the fluidity of the casting composition at the steel level, especially at temperatures between 700 and 1000 ° C. The use of said minerals or combinations thereof improves the quality of the transition layer between the non-molten casting powder and the non-molten slag layer, so that slag does not stick to the mold or crystallizer walls during casting, thereby eliminating casting disturbances or defects on the cast material.

Example of casting composition according to the invention:

1. Casting means for treating the level of steel in a continuous casting crystallizer:

silicon dioxide aluminum oxide calcium oxide soda calcined fluorspar coke ground mica pyrophyllite 22 wt. 4 wt. 30% by weight 13.9% w / w 10% wt. 20 i%. wt. 0.2 wt. 0.5% w / w 2. Casting means for level treatment

steel in continuous casting crystallizer:

silicon dioxide aluminum oxide calcium oxide 38 'wt. 5 wt. 20 l / w. fluorspar 4.8 wt. soda calcined 6 o / o wt. coke ground 25% w / w mica 1.2 o / o 3. Casting means for ingot casting: steel treatment at silicon dioxide 40 wt. calcium oxide 8 wt. alumina 10% wt. coke ground 25 wt. soda calcined 10% wt. mica 0.5 wt. talc 0.5 wt.

The casting composition according to the invention can advantageously be used to treat the steel level when casting steel into molds or crystallizers of a continuous casting machine.

Claims (1)

Subject Casting agent for treating the level of cast steel, containing 20 to 40 wt. % of silica, 3 to 10 wt. % alumina, 20 to 30 wt. % of calcium oxide, 5 to 20 wt. soda ynAlezu fluorspar and not more than 25% wt. % of ground coke, further comprising 0.1 to 10 wt. mineral substances crystallizing in a monoclinic system with tabular habit, ie mica, talc or pyrophyllite.