Method and apparatus for producing hollow fusing blocks

Abstract

To produce hollow ingots, at least two consumable electrodes having a diameter of at least 1.0 times the wall thickness of the hollow ingots are melted in a short, water-cooled mold that is flared particularly in a T-shape in the area of the consumable electrodes, wherein the inner wall of the hollow ingot is formed by a mandrel with a conicity of at least 1.5% that is installed in the mold from above, and the level of the liquid heel is maintained below the T-shaped flaring of the mold.

1 - 15 . (canceled) 
     
     
         16 . A method for producing hollow cast ingots by melting consumable electrodes in a slag bath in a short, water-cooled mould and using a water-cooled mandrel that is introduced into the mould from above, the method comprising:
 Simultaneously melting at least two consumable electrodes in the water-cooled mould, the electrodes having a diameter equivalent to at least 1.0 times the size of an annular gap between a part of the mould forming an outer casting cross section and the mandrel, the mould having a T-shaped flaring in an area of the consumable electrodes, wherein an inner diameter of the cast body is formed by the water-cooled mandrel that is introduced into the mould, the mandrel having a diameter that tapers downwardly in an area of a metal liquid level of a liquid heel; and adjusting the liquid level of the metal below a level of the flaring.   
     
     
         17 . The method as recited in  claim 16 , wherein the mandrel tapers downwardly at least in a solidification zone with a conicity of at least 1.5% relative to the diameter of the mandrel. 
     
     
         18 . The method as recited in  claim 16 , including measuring the liquid level of the metal by γ-ray source attached outside the mould and interacting with a receiver installed inside the mandrel, and keeping the liquid level of the metal constant depending on a melting rate of the consumable electrodes. 
     
     
         19 . The method as recited in  claim 16 , including adjusting a melting rate of the consumable electrodes so as to be equivalent in kg/h to 0.8 to 2.5 times a sum of outer and internal diameters in mm of the cast body. 
     
     
         20 . The method as recited in  claim 16 , including sending a melting current in parallel from one terminal of a single-phase melting current source through the at least two consumable electrodes into the slag bath and back to another terminal through a bottom plate. 
     
     
         21 . The method as recited in  claim 16 , including passing a melting current in parallel from one terminal of a single-phase melting current source into the slag bath through the at least two consumable electrodes and to another terminal of the current source via the mould and/or the mandrel. 
     
     
         22 . The method as recited in  claim 21 , including drawing off the melting current from the mould and/or the mandrel via electrically conducting elements in an area between the consumable electrodes. 
     
     
         23 . The method as recited in  claim 16 , including passing a total melting current of a single-phase current source into the slag bath through at least one of the consumable electrodes, and from the slag bath returning the melting current to the current source through at least a second of the consumable electrodes. 
     
     
         24 . The method as recited in  claim 16 , including creating horizontal movement of the liquid heel about a longitudinal axis of the cast body along the gap in an area of the liquid heel by an electromagnetic agitating coil. 
     
     
         25 . A system for producing a hollow cast body, comprising: a short, water-cooled mould; a water-cooled mandrel introducible into the mould from above; and at least two consumable electrodes having a diameter equivalent to at least 1.0 times a size of an annular gap between a part of the mould forming a casting cross section and the mandrel, the electrodes being arranged in the system simultaneously, the mould having a T-shaped flaring at least in an area of the consumable electrodes, the mandrel having a diameter that tapers evenly downwardly in an area of a solidification zone corresponding to a conicity of at least 1.5% relative to the diameter of the mandrel. 
     
     
         26 . The system as recited in  claim 25 , wherein the consumable electrodes are connected to one terminal of a single-phase melting current source, and a bottom plate is connected to another terminal. 
     
     
         27 . The system as recited in  claim 25 , wherein the consumable electrodes are connected to one terminal of a single-phase melting current source, and a connection is established from the mould and/or the mandrel to another terminal. 
     
     
         28 . The system as recited in  claim 27 , wherein the mould and/or the mandrel is/are provided with electrically conducting elements in an area between funnel-shaped flarings of the mould, the conducting elements being connected to one terminal of the melting current source. 
     
     
         29 . The system as recited in  claim 27 , wherein each of the at least two consumable electrodes is connected to one terminal of a single-phase melting current source in each case. 
     
     
         30 . The system as recited in  claim 25 , wherein the mould is provided with an electromagnetic agitating coil in an area of the liquid heel, the coil having lines of force that cause the liquid heel to move in a horizontal or tangential direction about a longitudinal axis of the cast body. 
     
     
         31 . The system as recited in  claim 25 , wherein a γ-ray source is located outside of the mould in a position corresponding to a desired liquid level of the metal, and a γ-ray receiver is located inside the mandrel for measuring the position of the liquid level of the metal.