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在连铸过程中,严格的钢水温度控制是保证连铸坯质量的前提,所以中包温度控制技术成为炼钢研究的方向之一。其中,中包等离子加热技术由于控制灵活,设备简单和清洁无污染具有广阔的应用前景。与感应加热相比,等离子加热在中包包型设计和维护成本上具有明显的优势。另外一面,与感应加热90%的加热效率相比,等离子加热仅有60%的加热效率。因此,如何提高等离子加热效率成为制约其发展的关键因素。ABB对于电磁搅拌和等离子加热相结合的方案做了大量的数值研究分析。结果显示,仅使用等离子加热,那么加热室的上部钢液由于浮力作用而滞流,导致传热效率低下,这是由于等离子加热形成了巨大的温度梯度造成的。结合使用EMS,加热室内的钢液以0.2~0.4 m/s的速度旋流,这加速了中包内钢水的对流传热,使得中包内的钢液温度均匀化,减小了中包水口处的温度波动,提高了等离子加热的热效率。同时,通过等离子加热和电磁搅拌相结合的方式能促进夹杂物上浮,达到净化钢水的作用。
In the continuous casting process, the strict control of molten steel temperature is to ensure the quality of continuous casting slab, so the temperature control technology in the package has become one of the directions of steelmaking. Among them, the package plasma heating technology has broad application prospects due to flexible control, simple equipment and clean and pollution-free. Compared with induction heating, plasma heating in the bag-type design and maintenance costs have obvious advantages. On the other hand, compared with 90% heating efficiency of induction heating, plasma heating has only 60% heating efficiency. Therefore, how to improve the plasma heating efficiency has become a key factor restricting its development. ABB for electromagnetic stirring and plasma heating scheme to do a lot of numerical analysis. The results show that using only plasma heating, the upper molten steel in the heating chamber stagnates due to buoyancy, resulting in inefficient heat transfer due to the huge temperature gradient created by the plasma heating. In combination with EMS, the molten steel in the heating chamber is swirled at a rate of 0.2-0.4 m / s, which accelerates the convective heat transfer of the molten steel in the sachet, homogenizes the temperature of the molten steel in the sachet and reduces the temperature of the bale Temperature fluctuations at the plasma heating to improve the thermal efficiency. At the same time, the combination of plasma heating and electromagnetic stirring can promote inclusions floating up to the role of purification of molten steel.