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 casting speed continuous casting covering slag used for ultra-low-carbon steel, comprising pre-melt material and accessory material. The percentage proportion of chemical components of the pre-melt 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 rest is micro-impurity contained in the materials. The alkalinity, namely CaO / SiO2, of the pre-melt material is 0.70 to 1.05; the viscosity is 0.2 to 0.5Pa.s; and the pre-melt 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 pre-melt 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 minerals. The high casting speed continuous casting covering slag not only can effectively reduce the carburetion of the covering slag to molten steel, but also can avoid negative impact on the metallurgical physicochemical property of the covering slag.

Description

Technical field [0001] The invention relates to auxiliary materials for steelmaking and continuous casting, in particular to high-speed continuous casting mold fluxes for ultra-low carbon steel. Background technique [0002] Continuous casting mold powder is a kind of powder or small granular steelmaking auxiliary material, which is used to cover the surface of molten steel in the mold of continuous casting machine. It has a variety of functions such as heat insulation, prevention of molten steel oxidation, absorption of inclusions, lubrication and heat transfer control. It is the last process element for the control of the final product of the steelmaking process—the quality of the cast slab. Unsuitable mold flux performance can cause casting The billet produces surface defects such as slag inclusions and cracks, which may even cause a breakout accident. Therefore, mold flux is an important means to ensure the smoothness of the continuous casting process and the surface quality ...

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