IF钢RH精炼理论研究与工艺优化

Theoretical study and process optimization of RH refining for IF steel

通过对RH真空精炼过程脱碳脱氮热力学和动力学的研究,分析了影响RH脱碳控氮的关键因素。在现场实践中采取预抽真空,改进RH真空室密封性、增设浸渍管颈部冷却装置及优化RH上升管供气管道结构,减少了浸渍管的开裂,既保证了气密性又延长了浸渍管使用寿命。在此基础上优化RH提升气体流量,使RH平均脱碳时间相比改进前缩短4.85 min,IF钢RH精炼结束碳、氮、T.O质量分数分别控制在10×10^(-6),17×10^(-6),24×10^(-6)。由于大包和中间包为钢液中夹杂物的上浮提供了机会,最终成品碳、氮和T.O质量分数平均值在12×10^(-6),18×10^(-6)和19×10^(-6)。

The key factors to affect the RH decarburization and denitrification were studied from the views of the thermodynamics and kinetics.The pre vacuumizing was adopted in industry practice,and the vacuum chamber tightness and the rising leg structure(the cooling device and structure of gas supply pipe)of RH were optimized,the cracks or leakages of impregnation tube could be avoided.It not only ensured the good tightness of RH process,but also prolonged the service life of impregnation pipe.Meanwhile,combining the process optimization of converter steelmaking and the optimization of RH rising gas flow,the average decarburization time of RH was reduced by 4.85 min.The mass fractions of carbon,nitrogen and T.O of IF steel after RH refining were 10×10^(-6),17×10^(-6) and 24×10^(-6),respectively.Furthermore,the ladle and tundish provided opportunities for the floating of inclusions in the molten steel.The average mass fraction of carbon,nitrogen and T.O in the final product were 12×10^(-6),18×10^(-6) and 19×10^(-6),respectively.