独立可调式组合电磁制动作用下钢/渣界面及异相物质迁移行为的基础研究

Turbulent flow of molten steel in the mold and resulting slag entrapment and inclusions are major technical problems for production of high quality billet in high efficiency continuous casting. How to inhibit the turbulent flow in the mold becomes the key to solve the problems of slag entrapment and inclusions. As an effective technique to control turbulent flow of molten steel, the electromagnetic brake (EMBr) technique is widely used in the continuous casting process and became an important means for controlling the molten steel flow in high speed slab continuous casting mold. However, owing to the limitation of effective region of the magnetic pole, the braking effect of the conventional EMBr was obviously affected by process parameters and electromagnetic parameters, such as the depth of submerged entry nozzle (SEN), SEN port angle, pole position, and so on.. This project chooses the high casting speed slab mold with EMBr as the research object, and proposes freestanding adjustable combination EMBr for the existing problems of process problems and structural problems for the conventional EMBr technology. The numerical simulation method was used to investigate the behavior of steel/slag interface and transport of different phases with freestanding adjustable combination EMBr. To explore the rule of molten steel flow control under the effect of freestanding adjustable combination EMBr and clarify its mechanism. The advantages of the freestanding adjustable combination EMBr that were obtained from this project can provide an important theoretical basis for further optimization of conventional EMBr systems and the exploitation and application of the new type EMBr technique . Meanwhile, it also has a significant and strategic meaning for electromagnetic brake technology with autonomous intellectual property rights in China.

结晶器内钢液湍流流动及其引起的卷渣、夹杂是高效连铸生产高品质钢坯的重大技术难题，如何抑制结晶器内钢液湍流流动成为解决卷渣、夹杂问题的关键。电磁制动技术作为一种有效控制钢液流动的方法广泛应用于连铸生产过程，成为控制高拉速板坯连铸结晶器内钢液流动的重要手段。然而，受磁极作用区域的限制，现行应用电磁制动技术的效果受工艺参数和电磁参数影响较大，如水口浸入深度、水口倾角、磁极位置等。. 本项目以高拉速板坯电磁制动结晶器为研究对象，针对现行电磁制动技术存在的工艺和结构问题，提出一种独立可调式组合电磁制动装置。采用数值模拟方法对其作用下的钢/渣界面及异相物质迁移行为进行研究，探索独立可调式组合电磁制动的控流规律，并阐明其控流机理，得出新型电磁制动技术的优势，为现行电磁制动技术的进一步优化和新型电磁制动技术的开发与应用提供重要理论依据，对于我国自主知识产权的电磁制动技术有重要的战略意义。

连铸结晶器内的冶金过程是一个非常复杂的过程，包括多相流流动（液钢-液渣-气泡）、异相物质迁移、凝固坯壳形成以及对非金属夹杂物和气泡的捕获等。这些过程均与连铸坯的质量密切相关。结晶器内钢液的湍流流动及其引起的卷渣、夹杂是高效连铸生产高品质钢坯的重大技术难题。电磁制动技术作为一种有效控制钢液流动的方法广泛应用于连铸生产过程，成为控制高拉速板坯连铸结晶器内钢液流动的重要手段。然而，受磁极作用区域的限制，现行应用的全幅一段电磁制动（EMBr Ruler）和全幅两段式电磁制动（FC-Mold）的效果受工艺参数和电磁参数影响较大，如水口浸入深度、水口倾角、磁极位置等。根据电磁制动技术的原理，同时结合传统电磁制动技术的优点，本项目首先提出了一种独立可调式组合电磁制动技术（FAC-EMBr：Freestanding Adjustable Combination Electromagnetic Brake），即采用一对水平磁极布置于SEN下方，用以制动钢液射流的冲击及抑制下回流钢液流速，进而减小非金属夹杂物和氩气泡被凝固坯壳捕获的几率；同时，在结晶器两侧窄面附近的宽面区域分别施加立式磁极，用以抑制上回流钢液流速，进而减弱上回流钢液对弯月面的冲击，稳定弯月面波动，减小卷渣发生的几率。此外，水平磁极和立式磁极的输入电流可以根据结晶器内实际钢液流动情况进行独立调节。所提出的FAC-EMBr技术已获得中国发明专利授权。在此基础上，开展了FAC-EMBr结晶器内的多物理场耦合数值模拟探索性研究，并将研究结果与传统电磁制动技术进行对比分析。目前国内现行应用的电磁制动技术主要为国外引进，新型FAC-EMBr技术的研究对于实现电磁制动技术自主创新、打破发达国家的专利垄断，以及推动行业内新技术发展具有重要的战略意义。本研究工作共发表SCI论文5篇，其中《Metallurgical and Materials Transactions B》2篇、《Metallurgical Research & Technology》1篇、《Processes》2篇。授权国家发明专利1项。培养毕业研究生1人，在读研究生2人。