Separation and Elimination of Inclusion Particles from Liquid Metal

金属制品中含有非金属夹杂物，会产生薄板断条、线材折断、硬加工开裂等严重问题，因此迫切需要新的方法来生产无夹杂物的产品。本研究进行了两方面的研究，一是开发了一种利用电磁力分离夹杂物的方法，二是提出了同时强化夹杂物团聚和分离的电磁流动和搅拌方法。首先，通过水银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夹杂物分离器中间包。结果表明，在普通金属产率的情况下，该磁选机能很好地分离大于30μm的夹杂物颗粒，并将高频磁场应用于…夹杂物的分离更多的离子。在高频炉中测量了硅对钢液的脱氧速率，发现控制速度的步骤是SiO_2的电磁分离。为了了解分离速度以及机械搅拌对分离的影响，进行了碳化硅颗粒与铝液的分离实验。观察到23μm颗粒的快速分离，并确定了防止电磁分离所需的搅拌速度。这些结果有助于日本国家钢铁电磁铸造项目防止夹杂物在初凝壳中堆积。作用于颗粒的分离力仅在单个球体上进行了理论计算。本文对两球绕流的分离力和电磁驱动流动进行了数值分析。这项研究被认为是揭示夹杂物群或簇状夹杂物复杂电磁现象的第一次尝试。发明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态镓的研究，观察到了良好的性能。研制了一种与泵原理类似的新型电磁搅拌器，并用液态气体对其性能进行了验证。较少

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