【作者】 孟劲松；

【导师】 姜茂发；

【作者基本信息】 东北大学 ， 钢铁冶金， 2006， 博士

【摘要】 LF钢包炉作为一种高效钢的二次精炼手段，借助电弧加热、造还原渣和底吹氩气搅拌等手段，以达到快速脱氧、脱硫、均匀钢水成分、温度以及有效去除钢中夹杂物的目的，在纯净钢冶炼方面发挥了巨大作用。探讨合理的精炼渣成分和底吹氩制度对于提高LF作业效率，降低深脱硫时间，优化转炉、精炼炉和连铸之间的工艺衔接和加快生产节奏均具有十分重要的意义。 本论文在鞍钢二炼钢LF合成精炼渣成分基础上，建立二次回归正交设计模型优化了鞍钢现场精炼渣成分，并考察了FeO含量和渣量对合成精炼渣脱硫效果的影响。以优化后的合成精炼渣成分为基准，通过实验室坩埚实验研究了工业原料和铝灰基脱硫剂对脱硫的影响，并借助感应炉装置比较了不同配方合成精炼渣的脱硫效果。结果表明，当渣中FeO、MgO含量不变时，随w（CaO）／w（SiO₂）增加，脱硫率均先增大后减小。在不同碱度条件下，Al₂O₃和CaF₂含量对脱硫效果的影响程度不同，当精炼渣中Al₂O₃、CaF₂含量过高时，增加上述任一组元含量，脱硫率均明显降低；LF冶炼低硫钢时，精炼渣中FeO含量应控制在0.5％以下，且渣量适宜，一般不大于20kg·t^-1钢；本实验条件下优化的最佳精炼渣组成为w（CaO）／w（SiO₂）9～11，Al₂O₃ 27％～29％，MgO 9％，CaF₂ 8％～10％，FeO小于0.5％；比较几种工业脱硫剂配方的脱硫效果，按照脱硫率从大到小的顺序依次为无氟电解铝灰，优化渣，预熔电解铝次，电解铝灰，预熔熔铸铝灰，熔铸铝灰。 针对鞍钢第二炼钢厂北区180吨LF精炼炉脱硫工艺，建立数学模型预测了底吹氩搅拌过程中钢水循环流动和混合行为。结果表明，采用数学模型方法和数值计算可以较好地预报吹气搅拌钢包体系中钢水湍流流动和混合现象；鞍钢二炼钢厂北区LF精炼钢包采用的弱偏心喷吹，在吹氩方式上是比较合理的，钢水同时存在明显的上下运动和水平运动；在目前采取的吹氩工艺制度下，钢水95％混匀时间在160s～317s之间，熔池中的钢水循环流量为103t·min^-1～175t·min^-1、熔池液面最大钢水流速为0.35m·s^-1～0.6m·s^-1以及熔池体系最大有效粘度在44kg·m^-1·s^-1～72kg·m^-1·s^-1范围，这些均表明钢包内搅拌强度处于更多还原

【Abstract】 Being considered as one of high- efficiency methods of second refining, LF was in virtue some measures of heating up by the electric arc, reductive slag and argon blowing to achieve the aims of rapid deoxidation, desulphurization, mixing the temperature and components of liquid steel and removing the inclusion from the liquid steel availably, which played a very important role in pure steel development. It was very important to find out the optimum composition of refining slag and argon bottom blowing routine, which will offer a great significance on reducing the time of desulphurization, harmonizing the LD, LF and continuous casting and accelerating the production rhythm.Base on the composition of refining slag for No.2 steel plant in Anshan Steel, a model of quadratic regressive perpendicular design was developed to optimize the composition of a new-type refining slag in the paper firstly, and the effect of FeO content and slag amount on desulphurization capacity was carried out accordingly. Then, considering the optimum slag composition as the base, effect of industrial materials and Al ash-bearing refining slag on the desulphurization capacity was performed in the laboratory experiment, and comparison of desulphurization capacity of all kind of agents with different industrials materials was carried out in an intermediate frequency faradic furnace. The results showed that, In the case of FeO and MgO content being a constant, the desulphurization ratio increased firstly then decreased with w （CaO）/w （SiO₂） increasing. Under the condition of different slag basicity, the influence degree of Al₂O₃ and CaF₂ on desulphurization capacity was dissimilar. When the content of Al₂O₃ and CaF₂ accounted for much ratio in the refining slag, whether any element content increased continuously or not, the desulphurization ratio will decrease. In the process of production of ultra-low-sulphur steel, FeO content was suggested to be less than 0.5%, and slag amount not more than 20 kg·t^-1. In the condition of those experiments, the optimum composition of refining slag was w （CaO）/w （SiO₂） 9-11, Al-2O₃ content 27%²9%, MgO content 9%, CaF₂ content 8-10% and FeO content less than 0.5% respectively. For the desulphurization capacity comparison of types of Al ash-bearing refining slag, the desulphurization ratio was list in term of value as followings, electrolytic Al ash without fluorine, optimum refining slag, electrolytic Al ash being更多还原