Continuous casting crystallizer mold powder of sheet billet at high casting speed

Abstract

The invention discloses continuous casting crystallizer mold powder of a sheet billet at a high casting speed. The mold powder comprises chemical components in percentage by weight as follows: 34%-44% of CaO, 2%-8% of Al2O3, 20%-30% of SiO2, 1%-9% of MgO, 5%-15% of F, smaller than or equal to 6.5% of Na2O, smaller than or equal to 5% of K2O, smaller than or equal to 6% of Li2O and the balance of carbon and uncontrollable impurities. Content of CaO in the mold powder is high, content of SiO2 in the mold powder is low, accordingly, the degree of purity of molten steel can be improved, simultaneously, MgO and CaO in the mold powder are alkaline earth metal oxides, Li2O, Na2O and K2O are alkali metal oxides, the melting temperature is low, the fluxing effect is achieved, the usage amount of a fluxing agent can be reduced, the probability of various crystal precipitation is reduced, so that the glass performance of the mold powder is improved, and the mold powder has a good lubrication effect at the high casting speed; accurate control on F content meets requirements of surface quality at the high casting speed, and lubrication is improved by means of an appropriate amount of Al2O3; and the mold powder can meet technological requirements of continuous casting of medium carbon steel such as SS400, Q345 and the like, moreover, the mold powder components have stable performance, and sequence casting can be realized.

Description

technical field [0001] The invention relates to a continuous casting mold mold powder, in particular to a mold mold powder for high-speed thin slab continuous casting. Background technique [0002] Continuous casting mold powder is based on CaO-SiO 2 The multi-component mixture based on the system has the functions of heat insulation, preventing secondary oxidation of molten steel, absorbing floating inclusions in molten steel, controlling horizontal heat transfer between slab and crystallizer, and lubricating slab, especially the latter two This function plays a decisive role in the smooth progress of the continuous casting process and the surface quality of the slab. At present, the casting conditions faced by thin slab continuous casting at high casting speed are very strict and harsh, which brings a series of difficulties to improve the quality of casting slab and stabilize continuous casting operation. For example, the casting speed of a steel plant can reach 4-6m / min...

AI Technical Summary

Problems solved by technology

However, when the casting speed reaches 4-6m / min, the existing mold slag is easy to form slag strands in the mold, which makes the friction coefficient between the mold and the slab large, the lubrication effect is not good, and the slab is prone to longitudinal cracking, and even Breakout occurs

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