Continuous casting of metal sheets and bands

Abstract

The invention provides an apparatus for the continuous casting of metal sheets and bands, including two rotatable roll-crystallizers having parallel axes located in the horizontal plane and defining between them a gap of adjustable width, and means for supplying metal melt to fill the gap; characterized by means for generating at least three substantially horizontal magnetic fields producing electromagnetic pressures adapted to act to contain at least one end face of the melt within the gap.

1 . An apparatus for the continuous casting of metal sheets and bands, comprising: 
 two rotatable roll-crystallizers having parallel axes located in the horizontal plane and defining between them a gap of adjustable width, and    means for supplying metal melt to fill said gap;    characterized by means for generating at least three substantially horizontal magnetic fields producing electromagnetic pressures adapted to act to contain at least one end face of said melt within said gap.    
     
     
         2 . The apparatus as claimed in  claim 1 , wherein each of said rolls-crystallizers comprises a central, substantially cylindrical portion having a core made of non-ferromagnetic steel and two stub axles, one on each side of said cylindrical portion and made of a ferromagnetic steel.  
     
     
         3 . The apparatus as claimed in  claim 2 , further comprising a tubular jacket for each of said cylindrical portions, said jacket being made of a material having high thermal conductivity and being provided at its inside with grooves communicating with ducts inside said core and said stub axles, for the circulation of a liquid coolant.  
     
     
         4 . The apparatus as claimed in  claim 3 , wherein said jackets are provided on their outside surfaces with grooves extending in an axial direction, into which grooves are inserted electrically insulated copper bars, with pairs of bars located in diametrical planes being connected to one another inside said core, forming frames.  
     
     
         5 . The apparatus as claimed in  claim 1 , further comprising two electromagnets, each facing one end of said gap and consisting of a C-shaped, laminated core having two sloping pole faces, said electromagnets being adapted to generate a high-frequency, alternating magnetic field.  
     
     
         6 . The apparatus as claimed in  claim 1 , wherein each of said sloping pole faces of said C-shaped core is disposed adjacent to the sloping face of one of two laminated, annular armatures fixedly attached to a flange of said stub axles.  
     
     
         7 . The apparatus as claimed in  claim 1 , wherein each of said stub axles of each of said roll-crystallizers is surrounded by a coil connectable to a source of alternating current and a source of direct current, and adapted to generate a low-frequency, alternating magnetic field and a direct magnetic field.  
     
     
         8 . The apparatus as claimed in  claim 1 , wherein said roll-crystallizers are each mounted in bearings attached to a beam of their own, which beams are slidably mounted on a chassis, whereby said gap can be adjusted by using screw means to vary the distance between said beams.  
     
     
         9 . The apparatus as claimed in  claim 1 , further comprising pump means and a conduit for feeding said melt into said gap via a distribution box.  
     
     
         10 . The apparatus as claimed in  claim 1 , further comprising a gear motor for each of said roll-crystallizers, each motor being connected to its roll-crystallizer via a coupling.  
     
     
         11 . The apparatus as claimed in  claim 1 , further comprising two arcuate stators surrounding said central portions of said roll-crystallizers with an air gap of at most 1 mm and covering part of the circumference of said portions, said stators having a width of between 0.5 to 0.9 of the length of said portions.  
     
     
         12 . The apparatus as claimed in  claim 11 , wherein said stators are supplied by a low-frequency (5-100 Hz) alternating m-phase (m≧3) voltage source and are adapted to produce a travelling magnetic field.  
     
     
         13 . The apparatus as claimed in  claim 1 , further comprising a take-up winder for the cast sheets emerging from said gap.  
     
     
         14 . A method for the continuous casting of metal sheets and bands, said method comprising the steps of: 
 providing means for generating at least three horizontal magnetic fields, a first, low-frequency, alternating field of a frequency between 5 and 100 Hz, a second, high-frequency, alternating magnetic field of a frequency between 2.5 and 10 kHz, and a third, direct magnetic field;    providing coolable, counter-rotating rolls defining between them an adjustable gap for determining the thickness of the cast sheets and means for delivering metal melt into said gap;    coordinating the rate of delivery of said melt, the rate of rotation of said rolls, the rate of cooling of said rolls and the intensity of said magnetic fields;    switching on said magnetic fields, and    pouring said melt into said gap.    
     
     
         15 . The method as claimed in  claim 14 , including the further step of: 
 providing means for generating a travelling magnetic field in the liquid metal filling the gap between said rolls, and    varying the parameters of said travelling magnetic field to vary the area of the contact surface of the liquid metal with said rolls.