300 t转炉终点碳氧积控制技术研究

Study on control technology of carbon-oxygen equilibrium at blowing end-point of 300 t BOF steelmaking

为了进一步提高转炉终点控制的稳定性,从改善动力学角度分析了影响碳氧积的主要因素,并通过工业试验确定了降低转炉碳氧积的控制技术。研究结果表明:转炉底吹元件为4支,底吹元件在炉底圆周上布局为0.55D时,钢水混匀时间最短;补炉料中粒径0~1 mm镁砂占比20%,高温抗折强度由改进前的4.2 MPa提升到了5.3 MPa,透气度提升了227%;采用底吹热更换技术后转炉终点氧质量分数进一步降低,由482×10-6降低至425×10-6,降低了57×10-6。通过以上措施,炉底底吹元件实现了全炉役可视化,全炉役碳氧积由0.002 38降低至0.001 78。

In order to further improve the stability of end-point control of converter,the main factors affected the carbon-oxygen equilibrium of converter were analyzed from the point of view of improving kinetics,and the control technology of reducing the carbon-oxygen equilibrium of converter was determined by industrial test.The results showed that,the mixing time of molten steel was the shortest when the number of tuyeres was 4 and the layout of tuyeres was 0.55D on the circumference of the converter bottom;the proportion of particles size of magnesia 0-1 mm in the fetting material was 20%,the high temperature flexural strength increased from 4.2 MPa to 5.3 MPa,and the permeability increased by 227%.The oxygen mass fraction at the end of the converter further decreased from 482×10-6 to 425×10-6,reduced by 57×10-6 by employing the quick change technology of the tuyere for converter.Through the above measures,the visualization of the tuyere was realizes in the whole campaign life,and the carbon-oxygen equilibrium reduced from 0.002 38 to 0.001 78 in the whole campaign life.