Equipment for supplying molten metal to a continuous casting ingot mould and method for using same

Abstract

The apparatus comprises a submerged entry nozzle ( 6 ) having outlets in the main casting plane (P) which differ in their direction of output and fall within two categories ( 7, 8 ), said nozzle being associated with two inductors ( 14, 15 ) opposite each other on each broad face ( 22 ) of the casting mold forming a gap which surrounds the nozzle and producing a traversing magnetic field covering the outlets of at least one category ( 7 ), means being provided for adjusting the intensity of the field or for moving it so as to be able to change the distribution between the outlets of the total flow of molten metal. In particular, implementing the invention makes it possible to adjust at any time that fraction of the metal flow which is directed toward the free surface ( 9 ) with respect to that, main, fraction directed toward the bottom of the mold. Advantageously, the invention applies to the continuous casting of steel slabs.

1 . An apparatus for feeding a mold of a plant for the continuous casting of products of rectangular cross section, such as slabs, with molten metal, which comprises: 
 a submerged entry nozzle ( 6 ) provided with outlets for the molten metal which lie in, or substantially in, the main casting plane (P) parallel to the broad faces of the mold, these outlets differing in their direction of outflow and falling within at least two separate types ( 7 ,  8 );    an inductive unit ( 14 ,  15 ) placed over the broad faces of the mold in order to produce thereon magnetic poles of opposite sign facing each other on each side of said main casting plane (P) and delivering, in its gap substantially surrounding the nozzle ( 6 ), a traversing magnetic field covering the outlets of at least one ( 7 ) of said types ( 7 ,  8 ); and    means ( 20 ,  21 ) for adjusting the relative intensity of said magnetic field, in the region of the outlets of said type ( 7 ) which is covered, with respect to the outlets of the other type ( 8 ), so as to be able to modify the distribution of the total flow of molten metal between all the outlets of said nozzle ( 6 ).    
     
     
         2 . The apparatus as claimed in  claim 1 , wherein said inductive unit is an electromagnetic unit consisting of at least one electromagnet.  
     
     
         3 . The apparatus as claimed in  claim 1 , wherein said inductive unit consists of inductors ( 14 ,  15 ) having a plurality of phase windings of the “traveling field” type, facing each other on each side of said main casting plane (P), and of an associated power supply which supplies each of said windings separately with DC current and wherein the means ( 20 ,  21 ) for adjusting the relative intensity of the magnetic field comprise means for moving the location of the magnetic poles in the gap of said electromagnetic unit.  
     
     
         4 . The apparatus as claimed in  claim 1 , wherein said inductive unit consists of at least one permanent magnet.  
     
     
         5 . The apparatus as claimed in  claim 2  or  3 , wherein said means for adjusting the relative intensity of the magnetic field comprise a device for varying the intensity of the electric current supplied to the inductive unit.  
     
     
         6 . The apparatus as claimed in  claim 2  or  4 , wherein said means for adjusting the relative intensity of said magnetic field comprise an arrangement in which the magnets or electromagnets can move in a sliding manner.  
     
     
         7 . The apparatus as claimed in  claim 3 , wherein said means for modifying the location of the magnetic poles in the gap consist of means for separately adjusting the intensities of the DC electric currents individually supplying the phase windings of said inductors ( 14 ,  15 ).  
     
     
         8 . The apparatus as claimed in any one of  claims 1  to  7 , wherein said inductive unit consists, on each side of the main casting plane (P), of two similar entities ( 14   a ,  14   b ) placed side by side on each side of the casting axis.  
     
     
         9 . The apparatus as claimed in any one of the preceding claims, wherein the submerged entry nozzle is a nozzle provided, in the main casting plane (P), with lower main outlets ( 7 ) directed toward the bottom of the mold and with upper secondary outlets ( 8 ) directed upward.  
     
     
         10 . The apparatus as claimed in  claim 9 , wherein the lower main outlets form one and the same outlet.  
     
     
         11 . A process for operating an apparatus as claimed in  claim 1  so as to feed a mold of a plant for the continuous casting of products of rectangular cross section with molten metal, wherein the relative intensity of the magnetic field produced by the magnetic poles of the inductive unit is adjusted by moving the position of the magnetic poles.  
     
     
         12 . A process for operating an apparatus as claimed in  claim 1  so as to feed a mold of a plant for the continuous casting of products of rectangular cross section with molten metal; wherein the relative intensity of the magnetic field produced by the magnetic poles of the inductive unit is adjusted by modifying the intensity of the electric current supplying said inductive unit.