低碳铝镇静钢精炼渣理化性能研究及动态调控

A Study of Physical and Chemical Properties of Slag for Low Carbon Alkilled Steel Refining Slag and Its Dynamic Control

为提升低碳铝镇静钢水的可浇性,基于低碳铝镇静钢精炼渣的热力学计算,研究典型组分CaO/Al2O3(C/A)、SiO_(2)、FeO对精炼渣液相线温度、1650℃黏度和表面张力的影响规律,结合精炼渣理化性能(熔点和黏度-温度曲线)测试结果,建立吹氩直上精炼渣动态调控模型,并投入生产实践应用。结果表明:随着C/A增加,精炼渣熔点在渣中SiO_(2)质量分数为5%时单调升高,在渣中SiO_(2)质量分数为10%时先降后升,另随C/A的增加精炼渣黏度及黏度-温度曲线的转折温度升高;精炼渣组分范围为C/A 0.75~1.50、SiO_(2)质量分数0~10%、FeO质量分数2%~6%时,可获得较低的液相线温度、较高的黏度和表面张力。生产实践中应用建立的模型可实现造渣物料的动态加入,精炼渣理化性能的稳定性得到显著提升,精炼渣的C/A和全铁(TFe)质量分数标准差明显降低;液相线温度、1650℃时的黏度和表面张力平均值分别降低6.9℃、增加0.0206 Pa·s和0.0109 N/m;全氧(TO)质量分数均值由2.78×10(-3)%下降为2.25×10(-3)%,改进了19.1%,钢水的可浇性得到显著改善。

In order to improve the castability of low carbon Al-killed steel,based on the thermodynamic calculation of low carbon Al-killed steel refining slag,the effect of typical components CaO/Al2O3(C/A),SiO_(2) and FeO on the liquidus temperature,viscosity and surface tension at 1650℃in the refining slag was studied.Combining the test results of the physical and chemical properties(melting temperature and viscosity-temperature curve)of the refining slag,a dynamic control model for the argon-blowing top-up refining slag was established and implemented in production practice.The results show that as C/A increases,the melting point of the refining slag increases when SiO_(2) mass fraction is 5%,while it first decreases and then increases when SiO_(2) mass fraction is 10%.Meanwhile,with the increase of C/A,the viscosity of refined slag and the inflection temperature of the viscosity-temperature curve also rise.When the composition range of refined slag is C/A 0.75-1.50,SiO_(2) mass fraction of 0-10%,and FeO mass fraction of 2%-6%,lower liquidus temperature,higher viscosity,and higher surface tension can be obtained.The model established in production practice can achieve the dynamic addition of slag-forming materials,significantly improve the stability of physical and chemical properties of refining slag,and significantly reduce the standard deviations of C/A and total iron(TFe)mass fraction in refined slag.The average values of liquidus temperature,viscosity and surface tension at 1650℃decrease by 6.9℃,increase by 0.0206 Pa·s,and 0.0109 N/m,respectively.The average mass fraction of total oxygen(TO)decreases from 2.78×10(-3)%to 2.25×10(-3)%,an improvement of 19.1%,and the castability of molten steel is significantly improved.