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在连铸过程中,保护渣起着提高产品表面质量、提供适宜的润滑和绝热保温等作用,因此,保护渣的正确选择对单个钢种是至关重要的。为了获得良好的表面质量,选择合适的保护渣目前仍然是一个难题。广泛采用的办法是使用供应商推荐的在其他工厂试验成功的保护渣以及在工业试验中获得成功的保护渣。这些新型保护渣的工业试验不仅导致极大的操作费用,而且带来了连铸机损坏的隐患(漏钢、结晶器磨损和停机)。此外,对于已选择的保护渣,即使在正常的成分范围内,其表现的性能也是不同的。新钢种需求的增长和当前经济的不平衡,导致塔塔钢铁公司欧洲工厂通过保护渣试验,寻找其替代品。为了研究与钢水成分、不同的浇注参数和产品表面质量相关的保护渣的行为,蒂塞德技术中心(TTC)启动了一项保护渣评估试验工作。在塔塔钢铁公司欧洲工厂进行了几次在线和离线的监测,收集了多个钢水试样、原始保护渣、渣膜和渣圈试样,并分析了不同浇次的有关保护渣、熔融层厚度、振痕和表面质量的数据。保护渣特性分析技术,如粘度测量、STA热分析、金相学、化学分析已经被应用于这个评估试验。试验观察到顶渣中氧化铝含量增加的同时,伴随有不同化合物的吸收和减少现象。试验证明:氧化铝、氧化钙、氧化硅和氧化锆化合物的增加和减少会影响保护渣的性能。
In the continuous casting process, mold flux plays the role of improving the surface quality of products, providing suitable lubrication and adiabatic insulation, etc. Therefore, the correct choice of mold fluxes is crucial to a single steel grade. In order to obtain a good surface quality, the selection of suitable mold flux is still a problem. A widely adopted approach is to use fluxes recommended by the supplier for successful tests in other plants as well as successful fluxes for industrial trials. Industrial testing of these new mold fluxes not only led to significant operating costs, but also led to damage to the caster (breakout, mold wear and shutdowns). In addition, the performance of the selected mold powder, even in the normal composition range, is different. The growing demand for new grades and the current economic imbalance have led Tata Steel’s European plant to pass a flux test to find alternatives. In order to study the behavior of mold fluxes associated with the composition of molten steel, different casting parameters, and surface quality of the product, the Tess Technology Center (TTC) initiated a slag assessment test. Several on-line and off-line monitoring was conducted at Tata Steel’s European facility. Several samples of molten steel, original mold flux, slag film and slag rings were collected and analyzed for slag, Thickness, vibration marks and surface quality data. Molten slag characterization techniques such as viscosity measurement, STA thermal analysis, metallography, and chemical analysis have been used in this evaluation test. The experiment observed that the content of alumina in the top slag increased along with the absorption and reduction of different compounds. Tests have shown that the increase and decrease of alumina, calcium oxide, silica and zirconia compounds can affect the properties of the mold flux.