邯钢二炼钢厂板坯中心偏析的研究

【作者】 卢玉英；

【导师】 王硕明； 王义芳；

【作者基本信息】 河北理工学院 ， 钢铁冶金， 2002， 硕士

【摘要】 本文对邯郸钢铁集团公司第二炼钢厂180×1200mm超低头板坯的中心偏析进行了实验研究和理论分析。通过硫印、酸洗、凝固组织的显示、万能金相显微镜的观察、扫描电镜分析等实验对铸坯中的夹杂物和中心偏析线进行定性定量分析,建立凝固传热数学模型,优化二冷配水制度,以及用凤凰软件模拟结晶器内流场,主要对浸入式水口进行模拟,考虑拉速、浸入深度、水口侧孔倾角等方面的影响,最后确定了最佳浸入深度和侧孔倾角。同时,建立了模拟板坯中心偏析的数学模型,对铸坯凝固过程中固相和液相溶质分配、有效分配系数的特征以及钢液流动与铸坯中心偏析的关系进行了分析阐述。并以上述试验为依据,证实了所采用偏析模型和流动模型的适用性,对铸坯中心偏析进行了较为成功的预测。综合上述试验,本文从炼钢原材料、钢水冶炼、保护浇注、结晶器内流场、凝固传热以及设备等多方面,对板坯中心偏析进行了综合研究,并以其作为依据,针对邯钢板坯的生产现状,对中心偏析的问题提出了一系列改善措施,使铸坯由中心偏析缺陷引起的废、次品率由1.33%降为0.13%,成功的解决了该厂板坯的中心偏析缺陷。例如,将多点矫直改为连续矫直,通过逐渐缩小二冷夹辊间距,实现了在不添置设备的情况下,对铸坯采取轻压下技术。更多还原

【Abstract】 The thesis studies the centerline segregation of the 180×1200mm superlow head slab from the second plant of the Handan Iron and Steel Corporation(HISCO) experimentally and theoretically. It searches the inclusions in the slab through experiments as follow: sulphur prints, acid etches, display of the solidified structure, observation with the multiple purpose metallograph and analysis with flying clectron microscope and so on. It erects heat-transfer mathematics model of solidification to optimize the second cooling. And it uses PHOENICS software to simulate current field in the crystallizer, especially the submerged nozzle. It optimizes the parameters of the submerged nozzle with an eye to draw speed, immersion depth and angle of submerged nozzle. And then, it erects mathematics models which simulate the centerline segregation in slabs. It analyzes the characters of the solute distribution in liquid and solid steel and the effective distribution coefficient. Meanwhile it expounds the relation between the flow of liquid steel and centerline segregation. According to the experiments, it has proved that the centerline segregation mathematics module and the flow mathematics module are applicable. And it forecasts the centerline segregation successfully.Through all of the experiments, it studies the centerline segregation in slabs synthetically in view of raw and processed materials for steelmaking, steel making, protecting pour, current field in the crystallizer, heat-transfer in solidification and casting facilities. On the basis of experiments, it proposes some improving measures which aim at HISCO. And it has succeeded. Such as, it adopts continuous rectification instead of multi-point rectification. It also adopts slight compressing technology without increasing any equipment by shortening rollpass in the second cooling.更多还原