Abstract：Al added to steel as alloying elements can not only refine grain size, inhibit aging phenomenon of low carbon steel, achieve a good combination of corrosion resistance, heat resistance and other properties of steel, but also to meet the new generation of automotive steel for automotive safety and lightweight requirements. However, when w([Al]) in molten steel is too high, the AlN generated before the solidification of molten steel rises to the interface of steel and reacts with the mold fluxes in the mold, which leads to changes in the composition and deterioration in properties of the mold fluxes, thus affecting the alignment of continuous casting and the surface quality of billet. FactSage7.2 thermodynamic software was used to calculate the formation thermodynamics of AlN in high-Al molten steel, the change of viscosity, melting temperature and break temperature of traditional CaO-SiO2 based mold fluxes after adding mass fraction of 2%, 4%, 6% and 8%AlN was analyzed by hemisphere point melting temperature tester and rotary viscometer, and the slag samples after adding AlN were tested by XRD. The results show that with the increase of w([Al]) and w([N]) in steel, the formation temperature of AlN increases and the total formation amount of AlN increases. When the amount of AlN increases from 0 to 8%, both the viscosity and melting temperature of mold fluxes increase. The viscosity increased about 0.032 Pa·s and the melting temperature increased about 13.5 ℃ with each added mass fraction of 1% AlN. When the mass fraction of AlN was 2%, the break temperature decreased from 1 002 ℃ to 980 ℃. When the mass fraction of AlN was more than 2%, the break temperature gradually increased to 1 117 ℃ at 8%AlN. With the increase of AlN content, the amount of cuspidine precipitation in the traditional CaO-SiO2mold fluxes decreases gradually in the process of condensation. When the AlN content is 8%, the main phase in the slag sample is CaF2.
王旭凤, 王强强, 张旭彬, 王谦, 何生平. AlN对高铝钢用CaO-SiO2基保护渣性能的影响[J]. 钢铁, 2022, 57(5): 64-71.
WANG Xu-feng, WANG Qiang-qiang, ZHANG Xu-bin, WANG Qian, HE Sheng-ping. Effect of AlN on properties of CaO-SiO2 based mold fluxes for high-Al steel[J]. Iron and Steel, 2022, 57(5): 64-71.
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2022, Vol. 57 
