高钛钢连铸结晶器内钢-渣界面反应行为

Steel-slag interface reaction behavior in continuous casting mold of high titanium steel

为了更好地控制高钛钢在连铸生产过程中的钢-渣界面反应,利用电磁感应炉对w([Ti])为0.05%~1.91%的3个级别高钛钢和传统的CaO-SiO_(2)系保护渣进行钢-渣界面反应试验,进而系统地分析了不同Ti含量对钢-渣界面反应的影响规律。基于双膜理论,考虑组元的质量传输,进而判断钢-渣界面反应的限制性环节,并结合质量守恒定律、化学平衡方程构建钢-渣界面反应动力学模型,揭示钢-渣界面反应机理,对钢-渣界面反应程度进行预测。研究结果表明,钢中w([Ti])为0.05%时,钢-渣界面反应较为微弱。w([Ti])为0.20%、反应达到平衡时,钢中w([Ti])从0.20%降低到0.01%,保护渣中w((SiO_(2)))从31.8%降低到29.1%,且反应达到平衡所需时间为600 s;当w([Ti])增加到1.91%、反应达到平衡时,钢中w([Ti])从1.91%降低到0.05%,保护渣中w((SiO_(2)))从31.77%降低到16.98%,且反应达到平衡所需时间为900 s。这说明钢中w([Ti])的增加明显加剧钢-渣界面反应程度,且延长反应达到平衡时所需时间。钢中Ti、Si以及保护渣中TiO_(2)、SiO_(2)的质量传输均对公式lnw([Ti])_(i)/w([Ti])_(0)与t的斜率有一定影响,说明4者的质量传输均为钢-渣界面反应的限制性环节,且Ti的质量传输对钢-渣界面反应程度的影响最为显著。将动力学模型的计算值与试验测定值对比发现,两者的变化趋势较为一致,说明该模型能够较好地预测钢-渣界面反应程度,进而为高钛钢和保护渣的钢-渣界面反应提供理论指导。

In order to control the steel-slag interface reaction of high titanium steel in the continuous casting process,the steel-slag interface reaction experiment between high titanium steel which the w([Ti])was 0.05%-1.91%and conventional CaO-SiO_(2) system mold flux was conducted by the electromagnetic induction furnace,and then the effect of different Ti contents on the steel-slag interface reaction was systematic analyzed.The rate controlling step of steel-slag interface reaction was judged by two-film theory and elements mass transfer.Meanwhile,the kinetic model was established combining the law of mass conservation and equation of chemical equilibrium,which revealed the mechanism and reaction extent of steel-slag interface reaction.It is found that the extent of steel-slag interface reaction is slight when w([Ti])is 0.05%.When the w([Ti])is 0.20%and the reaction is balance,the w([Ti])in steel and w((SiO_(2)))in mold flux are decreased from 0.20%to 0.01%and 31.8%to 29.1%,respectively,and the balance time is 600 s.When the w([Ti])is 1.91%and the reaction is balance,the w([Ti])in steel and w((SiO_(2)))in mold flux are decreased from 1.91%to 0.05%and 31.77%to 16.98%,respectively,and the balance time is 900 s.It is clearly stated that the extent and equilibration time of steel-slag interface reaction is increased with w(Ti).The mass transfer of Ti,Si in steel and TiO_(2),SiO_(2) in mold flux all have some impact on the slope of lnw([Ti])_(i)/w([Ti])_(0) and t,which means that the mass transfer of them are all the reaction rate controlling step,and the effect of Ti is the most.The change trends of calculated value from kinetic model and experimental value are consistent,which indicates that the model can describe the reaction extent of actual steel-slag interface,furthermore,it provides theoretical guidance for the steel-slag interface reaction of high titanium steel.