Continuous casting mold flux for automobile sheet

Abstract

The invention discloses continuous casting mold flux for an automobile sheet. The continuous casting mold flux is formed by mixing a base body and carbonaceous materials with the weight which is 1 percent to 2 percent of the total weight of the base body. The base body comprises, by weight, not more than 0.25 percent of Na2O, 0.5 percent to 4.5 percent of MgO, 0.3 percent to 1.0 percent of Fe2O3, 5 percent to 25 percent of Al2O3, 0.5 percent to 6.5 percent of Li2O, 0 percent to 16 percent of BaO, 5 percent to 9 percent of F, 20 percent to 40 percent of SiO2 and not more than 2 percent of impurities. The weight ratio of CaO to SiO2 ranges from 0.9 to 1.4. The base body meets the requirements that the proportion of a pre-melting portion is not less than 70 percent, the melting point of the base body ranges from 1100 DEG C to 1200 DEG C, the viscosity ranges from 0.25 Pa.s to 0.45 Pa.s at the temperature of 1300 DEG C, and the surface tension ranges from 0.43 N / m to 0.53 N / m at the temperature of 1400 DEG C. The continuous casting mold flux has the higher viscosity and the higher surface tension, and the slag inclusion occurrence rate of a continuous casting sheet billet of the automobile sheet is better reduced.

Description

technical field [0001] The invention relates to an auxiliary material used in a continuous casting process, in particular to a continuous casting mold slag used in a continuous casting process of an automobile plate. Background technique [0002] Continuous casting mold slag is a powdery or small granular steelmaking auxiliary material. It is a synthetic material added to the crystallizer and covered on the surface of molten steel during the continuous casting of molten steel. In the continuous casting process of automobile steel, carburization caused by mold slag and subcutaneous slag inclusion are two main quality defects of automobile plate. At present, the research on preventing the carburizing of ultra-low carbon steel is relatively mature, and there are several typical solutions, such as Chinese patent CN1872451A discloses adding 0.25-2.0% carburizing agent and Chinese patent CN1245266C discloses adding 0.5-5.0% carburizing agent Combustion agent, by reducing the amo...

AI Technical Summary

Problems solved by technology

Existing technologies and patents have done a lot of work to increase the viscosity of mold flux, but too high viscosity will lead to unsmooth continuous casting process, prone to sticking and breakout, and it is difficult to meet the long-term stable operation of actual production

In terms of reducing the interfacial tension of steel slag, although the Na 2 O was reduced to 1.6%, but in fact Na 2 O, a low surface tension component, is still relatively high, and SiO in slag 2 (It is also a low surface tension component) higher than 40%. Together, they still have a strong effect of reducing the surface tension of mold slag slag, and it is still difficult to avoid slag entrainment, and the slag inclusions contain Na 2 O is relatively high to form sodium aluminosilicate, which is then converted into sodium hydroxide in the subsequent process, and the harm to the cold plate is also difficult to avoid.

And for the use of low SiO 2 Although the reactivity between the steel slags is weakened, the stability of the mold slag is poor and cannot meet the requirements of stable industrial production, and the Na 2 O is greater than or equal to 4%, and the hazards of sodium hydroxide formed are more prominent

Therefore, prior art for Na 2 Insufficient understanding of the severity of O hazards, high Na content remains in mold flux 2 O content, while simply reducing SiO 2 It does not fully take into account the needs of stable production of continuous casting