High casting speed continuous casting covering slag used for ultra-low-carbon steel

Abstract

The invention relates to assistant materials used for continuous casting of steelmaking, in particular to a high speed continuous casting mold flux used for ultra-low-carbon steel, comprising a premelting material and an accessory material. The percentage proportion of chemical components of the premelting material is as follows: 30 to 40 percent of CaO, 35 to 45 percent of SiO2, 3 to 10 percent of Al2O3, 1 to 5 percent of MgO, 4 to 8 percent of F, 6 to 12 percent of Na2, 0.5 to 3 percent of B2O3, and the balance being microimpurity contained in raw materials. The alkalinity, namely CaO / SiO2, of the premelting material is 0.70 to 1.05; the viscosity is 0.2 to 0.5Pa.s; and the premelting material is processed by pre-melting. The accessory material comprises 0.7 to 0.9 percent of simple-substance carbon and 0.25 to 1.5 percent of boron flame retardant, wherein a small part of the boron flame retardant is added in the form of borax and the majority of the boron materials is pre-melted into the premelting material; and the content of B2O3 in the pre-melted slag is 0.5 to 3 percent. The accessory material also comprises 0.2 to 0.8 percent of CaSi powder and 0.8 to 4.0 percent of manganese ore. The high speed continuous casting mold flux not only can effectively reduce the carburetion of the mold flux to molten steel, but also can avoid negative impact on the metallurgical physicochemical property of the mold flux.

Description

technical field [0001] The invention relates to auxiliary materials for steelmaking and continuous casting, in particular to high-speed continuous casting mold slag for ultra-low carbon steel. Background technique [0002] Continuous casting mold flux is a powdery or small granular steelmaking auxiliary material used to cover the surface of molten steel in the mold of a continuous casting machine. It has multiple functions such as thermal insulation, preventing oxidation of molten steel, absorbing inclusions, lubricating and controlling heat transfer. Surface defects such as slag inclusions and cracks occur in the billet, and even cause steel breakout accidents in serious cases. Therefore, mold flux is an important means to ensure the continuous casting process and the surface quality of the slab. [0003] Mold flux is usually made of CaO, SiO 2 Mainly binary system, with external CaF 2 、Na 2 O. Li 2 Flux such as O, and a small amount of Al 2 o 3 , MgO, MnO, FeO and ...

AI Technical Summary

Problems solved by technology

[0007] The mold slag mentioned above can effectively reduce the carburization effect on the molten steel when the casting speed of the continuous casting machine is low and the fluctuation of the molten steel surface is small. The direct contact between the layer and the molten steel, the carburization phenomenon is obvious

At the same time, the high casting speed has higher requirements on the performance of the mold flux and requires more stable metallurgical properties. If the amount of the flame retardant or flame retardant added in the above patent is too small, it will not be able to play its due role. If the amount is too large, it will It will destroy the related properties of mold powder, so it can no longer meet the requirements of high casting speed mold powder for ultra-low carbon steel