Methods and facilities for suppressing vortices arising in tundishes or ladles during their respective discharge

Abstract

A method is provided for suppressing a vortex arising in a tundish or ladle at the lowering of the free surface of the melt below a critical level using a rotating magnetic field excited in the melt above an outflow pipe by an RMF inductor of a special design.

1 . A method of suppressing a vortex arising in a tundish or ladle at the lowering of the free surface of a melt below a critical level using a rotating magnetic field (RMF) continuously excited by  5  m-phase current in the melt above an outflow pipe, wherein the direction of RMF rotation is opposite to the direction of melt rotation in the vortex.  
   
   
       2 . The method of  claim 1 , wherein the direction of the RMF rotation is varied with a certain frequency and on-off time ratio.  
   
   
       3 . The method of  claim 1 , wherein the RMF is amplitude and/or frequency modulated, wherein a modulation frequency exceeds a carrier frequency.  
   
   
       4 . The method of  claim 1 , wherein the RMF is excited in a discontinuous manner with a certain on-off time ratio.  
   
   
       5 . The method of  claim 1 , wherein the RMF is excited with a certain delay after the onset of free melt surface lowering, depending on the stationary melt level and conditions of vortex formation.  
   
   
       6 . The method of  claim 1 , wherein the RMF intensity is varied during the melt discharge.  
   
   
       7 . The method of  claim 1 , wherein the frequency of current exciting the RMF is varied during the melt discharge.  
   
   
       8 . A facility realizing the method of any one of claims  1 - 7  constituting an explicit-pole inductor wherein the number of poles is a multiple to the number of current phases, comprising a magnetic circuit, windings, and pole pieces, which are mounted under the bottom of the tundish or ladle around the outflow pipe, wherein the magnetic circuit back is made of ferromagnetic material in the form of a flat disk with a central hole in which the outflow pipe is arranged, wherein the poles have a trapezoidal cross-section with windings which are perpendicular to the plane of the back, and wherein the pole pieces are air-cooled, made in the form of fragments of a hollow cone, and arranged in the lining of the bottom of the tundish or ladle around the discharge hole.  
   
   
       9 . The facility according to  claim 8 , wherein the pole pieces of the inductor are made in the form of fragments of a hollow cylinder with a conical inner surface.  
   
   
       10 . The facility of  claim 8 , wherein the magnetic circuit of the inductor is made of ferroceramics.  
   
   
       11 . The facility of  claim 8 , wherein the magnetic circuit of the inductor is made in the form of a thin-wall jacket filled with iron powder consisting of electrically insulated particles.