2006 Volume 92 Issue 6 Pages 357-363
In metal processing, confinement of a molten metal without mechanical contact is of great interest. For example, in a galvanizing process a sink roll, which is set in a zinc bath for changing the moving direction of steel strip, causes troubles such as deteriorating the quality of products and productivity. A new galvanizing process by using a high magnetic field which does not equip the sink roll has been proposed, where the steel strip is inserted from an inlet hole opened on the bottom of the zinc bath. Thus the stable confinement of a molten metal at the hole is crucial technical matter. The confinement of a molten metal and controlling of its flow are also essential for a cold crucible, which is indispensable for precision castings of reactive or high melting point metals like titanium and zirconium alloys. So far alternating and traveling magnetic fields have been applied for confinement of a molten metal, where unstable phenomena in hydrodynamic motion inevitably appear, so that the development of a stable confinement of a molten metal has been strongly desired. The simultaneous imposition of D.C. magnetic field and D.C. electric current is a promising method in respect of energy efficiency, however it easily generates unstable phenomena of the molten metal when a large electric current is imposed under a weak magnetic field.
In this paper, a new method of confining a molten metal by applying D.C. magnetic field and D.C. electric current has been proposed. The usefulness of the method, which is promising in industrial applications, has been demonstrated by a model experiment using a molten metal. That is, a molten metal has been more stable confined by using plural pairs of electrodes.