钢中Al2O3夹杂在耐材壁面动态沉积/剥落行为的应用基础研究

Aluminum is widely used in steelmaking process due to its high efficiency and economical deoxidation ability, function of grain size refinement and structural strengthening. However, the clogging of submerged entry nozzle(SEN) caused by aluminum deoxidation product is a serious problem for the continuous casting process. The key technology for improving casting ability is to quantify the influence factors and characterize the dynamic process of the SEN clogging accurately. Present study intends to establish multi-scale prediction model between microscopic particle movement, mechanical behavior, deposition & peeling conditions and the phenomenon of un-symmetric flow, level fluctuation and slag entrapment due to the nozzle clogging. The influence factors of the micro particle deposition & peeling off are controlled independently to achieve the control of the unsteady state process such as un-symmetric flow, level fluctuation and slag entrapment etc. during the continuous casting process. The dynamic growth process of the inclusions, the trajectories of macro particles from the peeling off process, and the distribution of inclusions in slab can be predicted based on the model.

金属铝由于高效、经济的脱氧能力和对钢基体晶粒的细化和组织的强化作用，在炼钢过程被广泛应用，但铝脱氧产物导致的水口结瘤却是长期以来困扰连铸的难点问题。解决水口结瘤的关键是量化解析水口结瘤的影响因素和准确表征水口结瘤的动态进程。本研究拟将微观粒子的运动状态、受力行为、粒子的沉积/剥落的条件与水口结瘤物沉积/剥落及结瘤导致的偏流、液面波动、卷渣等宏观流动特征建立关系，构建微观-介观-宏观的多尺度预测模型，通过对微观粒子沉积/剥落的独立影响因素的控制，达到对浇注过程非稳态现象（偏流、卷渣等）的调控，借助模型计算推断夹杂物沉积长大的动态进程及剥落颗粒物随流动的运动轨迹，预测剥落大颗粒夹杂物在铸坯中的存在分布位置。

铝是炼钢过程常见的脱氧剂，脱氧效率高、经济性好，但铝脱氧产物容易沉积在浸入式水口内壁，造成浸入式水口堵塞，严重制约连铸工艺和铸坯质量。本研究为解决连铸上述的瓶颈问题，从以下方面开展了研究：一、夹杂物在耐材壁面动态沉积/剥落的影响因素解析；二、夹杂物/钢液/耐材间的多相反应行为研究；三、水口结瘤物沉积状态与宏观流场特征的关系研究；四、夹杂物在耐材壁面动态沉积/剥落的多尺度预测模型。通过以上研究，明确了夹杂物微观形态、运动状态、受力行为对夹杂物沉积/脱落的影响规律；量化解析了引起水口结瘤的影响因素，确定了夹杂物在不同特征耐材壁面上的动态沉积/剥落的临界条件；建立了定量描述水口结瘤物沉积/剥落动态进程演化的“微观-介观-宏观”多尺度预测模型，可以预测不同条件下水口结瘤的动态演化进程，以及夹杂物微观沉积/脱落对宏观流动特征（偏流、液面波动、卷渣）的影响规律。依托本项目，项目申请人在德国亚琛工业大学进行了访学交流，并多次与国内外相关研究团队开展了学术成果交流；研究团队共发表SCI/EI论文11篇(其中SCI论文10篇，EI论文1篇)，依托项目培养博士研究生1名，硕士研究生3名，本科生毕设1名。结瘤沉积流动的表征方法授权发明专利1项，多尺度结瘤模型发表在Powder Technology国际颗粒领域顶级期刊发表，得到同行的认可。依托本项目的研究成果，为包钢开发稀土型汽车板多炉连浇和稀土汽车板稳定生产提供了理论和应用指导，项目成果获2021年冶金科学技术奖二等奖（排名第九）。项目已按既定要求完成申请书内全部考核指标。