Hybrid control of surface behavior on molten metal by mold oscillation andintermittent alternating magnetic field

In a continuous casting of steel, the surface quality of a slab is strongly influenced by mold oscillation. Recently, a new idea in which the impositi on of an intermittent alternating magnetic field was synchronized with the mold oscillation has been proposed for the improvement of surface quality u nder a concept of "soft contacting solidification". The concept is based on the information that the reduction of the contact pressure between a mold and a melt under the imposition of an alternating magnetic field results in good surface duality. However, the most suitable timing for the imposition of the magnetic field in a mold oscillation cycle still has not been deter mined. To clarify the behavior of the surface wave motion, which is closely related to the contact pressure between a mold and a melt, we have conduct ed a model experiment on the free surface motion of a molten gallium excite d by the synchronous imposition of the intermittent alternating magnetic fi eld and the simulated mold oscillation. The phase difference between the mo ld oscillation and the magnetic field has been studied from the viewpoint o f the suppression of the surface motion. It has been found that the wave sh ape excited by the synchronous imposition agrees with the numerical superpo sition of the two wave shapes excited independently by the magnetic field a nd the mold oscillation, except for the case where a small surface excitati on is observed.