Separation and Elimination of Inclusion Particles from Liquid Metal

金属制品中含有的非金属夹杂物会导致薄板中的碎屑、线材的折断以及硬加工中的裂纹等严重问题，因此强烈需要能够生产无夹杂物产品的新方法。本研究从两个方面进行了研究，一是开发了利用电磁力的分离方法，二是提出了电磁流动和搅拌的方法，同时促进夹杂物的团聚和分离。首先，通过汞模型实验研究了交流电流和交流磁场同时作用下的电磁分离。该方法是为钢的连铸过程设计的一种带夹杂物分离器的连铸机。实验结果表明，在常规产金属率条件下，该分离器可将大于30 μm的夹杂物颗粒完全分离，并将高频磁场应用于夹杂物分离， 关于我们 离子。在高频炉上测定了钢液硅脱氧速率，发现控制脱氧速率的步骤是SiO_2的电磁分离。为了解SiC颗粒的分离速率以及机械搅拌对分离的影响，进行了SiC颗粒从铝液中分离的实验研究。观察到23 μm颗粒的分离速度非常快，并确定了防止电磁分离所需的搅拌速率。这些结果有助于日本国家电磁铸钢项目防止夹杂物在初始凝固壳中的积聚。仅对单个球体作用于颗粒的分离力进行了理论评估。本文对电磁驱动下的双球分离力和绕流进行了数值分析。该研究首次揭示了夹杂物群或团簇的复杂电磁现象，提出了一种基于扭转旋转磁场的新型电磁泵。通过使用固体金属棒和液体Ga的研究观察到优异的性能。研制了一种原理与泵相似的新型电磁搅拌器，并以液态镓为实验材料对其性能进行了验证。少

Nonmetallic inclusions included in metal products result in severe problems like slivers in thin plates, snapping of wires, and cracking in hard processing, therefore new methods by which inclusion-free products can be produced are strongly required. In this study, two investigations are made, one is to develop a separation method by using electromagnetic force, and the other is to propose electromagnetic flowing and stirring methods, which enhance agglomeration and separation of inclusions in the same time.First of all, electromagnetic separation by simultaneous imposition of AC current and AC magnetic field was studied by a mercury-model experiment. This method was designed for the continuous casting process of steel as a tundish with inclusion separator. It was estimated that the inclusion particles larger than 30 μm could be separated perfectly by this separator in the condition of ordinary metal-producing rate.High frequency magnetic field was also applied to the inclusion separat … More ion. Deoxidation rate of liquid steel by silicon was measured in a high frequency furnace, and the rate-controlling step was found to be the electromagnetic separation of SiO_2. To know the separation rate and the effect of mechanical stirring on the separation, experiments of SiC particle separation from liquid Al were carried out. Very fast separation was observed for 23 μm particle and the stirring rates required for preventing electromagnetic separation were determined. These results helped the Japanese national project of electromagnetic casting of steel to prevent inclusion accumulation in a initially solidified shell.The separation force acting on particle has been evaluated theoretically only for a single sphere. In this study, a numerical analysis was made on the separation force and electromagnetically driven flow around two spheres. This study is thought to be the first trial to reveal the complex electromagnetic phenomena of inclusion swarm or clustered inclusions.A new electromagnetic pump based on a twisted-rotating magnetic field was invented. Excellent performance was observed by the study using solid metal rods and liquid Ga. A new electromagnetic stirrer using similar principle with the pump was developed and its performance was verified by using liquid Ga. Less