Electro-magnetic control of bubble size in gas injection into molten metal

K. Takeda

Advanced Technology Ressearch Laboratories, Nippon Steel Corporation, 1618, Ida Nakahara-ku Kawasaki 211, Japan

Abstract
A novel method by using electromagnetic means is proposed to control the formation of bubbles injected into a molten metal. It is demonstrated that the uniform electromagnetic force produced by a magnetic field together with an electric current works to enhance or reduce gravity. Effective change of the gravity by the electromagnetic field affects the kinetics of bubble separation from gas injection nozzle facing upward. When an alternating electromagnetic force was imposed to the molten metal, it was found that bubbles of the injection gas were formed at a frequency synchronized with that of the applied ac force field. By changing the intensity and the frequency of the applied force field, bubble size can be controlled. Figs 7, refs 2.