Ca处理“液相窗口”及夹杂物变性热力学研究

Thermodynamic study on calcium treatment of “liquid phase window” and inclusions modification

研究“液相窗口”控制钢液中非金属夹杂物变性对于防止连铸过程浸入式水口堵塞具有重要意义。基于某钢厂中高碳钢生产实践,在重点考虑Si元素和温度对“液相窗口”影响的基础上,通过热力学理论计算与工业试验相结合,对Ca处理过程“液相窗口”进行了研究。结果表明:“液相窗口”随钢液中T[O]、T[Al]、[S]含量及温度变化而变化;低温“液相窗口”一定位于高温“液相窗口”范围内;钢液中[Si]含量在某些条件下对“液相窗口”影响较大;并提出了“部分液相窗口”和“完全液相窗口”的概念;确定了某钢厂S50C生产最佳Ca质量分数范围为(18~27)×10^(-6)。

It is important to study the “liquid phase window” and control non-metallic inclusions modification for prevention of submerged entry nozzle blocking during continuous casting. Based on the production practice of medium and high carbon steel in a steel plant, the “liquid phase window” during calcium treatment was studied by combining thermodynamic theoretical calculation and industrial test, which was based on considering the influence of silicon element and temperature on the “liquid phase window”. The results show that the “liquid phase window” varies with T[O], T[Al], [S] content and temperature, and the low-temperature “liquid phase window” must be within the range of high-temperature “liquid phase window”, and the silicon content in molten steel has a great influence on the “liquid phase window”. The concepts of “partial liquid phase window” and “complete liquid phase window” are proposed, and the optimum calcium content range of S50 C production in a steel plant is determined to be(18-27)×10^(-6).