Recent Progress of EPM in Steelmaking, Casting, and Solidification Processing

Abstract

Recently, twin torch plasma heating became common rather than single torch which demands anode in the tundish wall. Recent Progress of EPM in Steelmaking, Casting, and Solidification ProcessingHideyuki YASUDA, 1) Takehiko TOH, 2) Kazuhiko IWAI 3) and Kazuki MORITA 4) 1) Department of Adaptive Machine Systems, Osaka University, Suita, Osaka 565-0871 Japan.2) Technical Development Bureau, Nippon Steel Corporation, 20-1, Shintomi, Futtsu, Chiba 293-8511 Japan.3) Department of Materials, Physics and Energy Engineering, Nagoya University, Nagoya, Aichi 464-8603 Japan. 4) Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 Japan.(Received on February 13, 2007; accepted on February 22, 2007 ) This paper reviews recent trends of electromagnetic processing in steelmaking, casting and solidification processing. Electromagnetic vibration for controlling the solidified structure and application of microwave in materials processing are also presented. Aim of this paper is to prospect the recent trends in electromagnetic processing of materials.KEY WORDS: continuous casting; solidification; container-less process; electromagnetic vibration; microwave.ISIJ International, Vol. 47 (2007), No. 4, Review ment of steel cast is under trial. With AC field, the plasma arc is reciprocally moved and the fan shape plasma is obtained as a time-averaged figure. This technique may enable the loss free surface treatment of the steel semi-products. 9) BrakingThe in-mold electromagnetic braking technique started as a localized MHD application 10) to brake directly the molten steel stream discharged from the submerged entry nozzle. At that time, however, the technique had several problems concerning the stability of braking effect and the resultant metallurgical benefits. The new technique of stably controlling the molten steel flow in the mold was developed by applying a level DC magnetic field (LMF) across the mold width to discover a new function of suppressing mixing in addition to the conventional functions ensuring the slab quality. [11][12][13] The metallurgical effects of LMF are to minimize the penetration of oxide inclusions into the cast and to stabilize the steel flow in the mold so as to avoid the entrainment of liquid flux into the cast. The latter function enhanced the rapid introduction of this technique to the thin slab caster, which has high casting speed characteristics. Another application of this technology is to minimize the transition region at the ladle change by imposing a level magnetic field during the sequential casting.When an external DC magnetic field is applied to moving electrically conductive fluid, electric current is induced in the fluid. The electric current in the fluid makes a circuit to satisfy the law of conservation of electric current, according to the electrical boundary condition and generates electromagnetic braking forces on the fluid. The electric current path formed in this way contains components in the direction opposite to the one for th...

The effect of fluid flow on the solidification of Ni2B from the undercooled melt

“…15 As extensively reviewed in the literature, static magnetic fields are known to stabilize fluid flow in electrically conductive materials (magnetic damping). [28][29][30][31][32] In the present work, this effect is investigated on the dendrite growth dynamics measured under the condition of natural convection present in MF experiments, which are compared to results obtained in the presence of an external homogeneous static magnetic field of 1.2 T.…”

Modification of the Primary and Peritectic Phases in Directionally Solidified Cu-20 wt.% Sn Alloy by Magnetic Field

“…[1][2][3] Usually, direct current magnetic field device can damp the natural convection and promote the development of equiaxed structure by magnetohydrodynamics (MHD) damping effect. However, due to the thermoelectric effect, an inner thermoelectric current loop can form around the solid-liquid interface when there is a temperature difference between the joints.…”

Aluminiumαgrain refinement in A354 by rotating magnetic field (RMF)

“…1 There are several means, which, when combined, can achieve a finer proeutectic a grain during solidification:…”

“…7,8 Others state that they are due to pressure differences caused by the oscillation of liquid that causes cavitation and consequently some nucleation of embryos. 1,9,10 Yet, others claim that there is an undercooling effect due to the magnetic intensity. There is some general agreement that the mass transportation of the cooler liquid from the mould surface to the hotter regions increases the solidification rate.…”