弯月面凝固过程渣钢界面张力的演变规律与影响机制

In the situation of casting with mould flux,oscillation marks and associated defects are closely related to the meniscus solidification, meniscus shape deformation, and overflow of liquid steel near meniscus. Meniscus shape deformation and overflow of liquid steel are all induced by the force unbalance on the meniscus and essentially effected by the variation of slag-steel interfacial tension. To explore the evolution of the slag-steel interfacial tension in the mould meniscus zone, sissile drop method would be adopted to measure the slag-steel interfacial tension taking advantage of high temperature Laser confocal scanning microscope (CSLM) during the process of phase transition, surface active elements segregation and nonmetallic inclusions precipitation associated with meniscus solidification, combining interface dynamic observation and chemical component analysis, the evolution and effect mechanism of interfacial tension would be determined. The results would be much significance for the force analyzing on meniscus, mechanism of meniscus deformation and overflow of liquid and mechanism perfection of oscillation mark formation, and can provide foundmental data and theoretical support for the optimization of continuous casting parameters to control the formation of oscillation marks and associated defects.

在保护渣保护浇铸条件下，连铸坯振痕及其相关缺陷的产生与弯月面的凝固、变形和钢水溢流行为密切相关。弯月面变形和溢流行为均是弯月面受力不平衡的结果，在本质上受到渣钢界面张力变化的影响。为探索连铸结晶器内弯月面区域渣钢界面张力的演变规律，本项目拟采用静滴法，利用高温激光共聚焦扫描显微镜（CSLM）系统测定弯月面凝固相变过程、表面活性元素偏析过程和非金属夹杂物析出过程的渣钢界面张力，并结合渣钢界面结构动态观察和成分分析，确定渣钢界面张力的演变规律及其影响机制。研究结果对于透彻解析弯月面的受力状况，明确弯月面变形和钢水溢流的发生机制，完善振痕产生机理具有重要意义，可为指导连铸工艺参数优化，控制振痕及其相关缺陷的产生奠定理论基础。

在现代连续铸钢工艺条件下，连铸坯振痕及其相关缺陷的产生与结晶器内弯月面的凝固、变形和钢水溢流行为密切相关，在本质上受到渣钢界面张力变化的影响。为探索连铸结晶器内弯月面区域渣钢界面张力的演变机制，本项目在渣系成分设计和钢样冶炼与制备的基础上，系统测定了弯月面凝固相变过程、表面活性元素偏析过程和非金属夹杂物析出过程的渣钢界面张力。结果表明，钢液凝固过程中，渣金界面张力显著降低；凝固过程中钢中表面活性元素的偏析、非金属夹杂物的析出均会加剧该过程。连铸过程中渣金界面张力的突变将导致钢水溢流行为的发生，溢流钢液形成新的弯月面，如此循环即可导致周期性振痕的产生。研究结果对于透彻解析弯月面的受力状况，明确弯月面变形和钢水溢流的发生机制，完善振痕产生机理具有重要的科学意义，对于指导连铸工艺参数优化，控制振痕及其相关缺陷的产生具有重要应用价值。