Method and apparatus for melt flow control in continuous casting mold

Abstract

A method and apparatus for continuous casting of metal. The flow of molten metal is altered to eliminate or reduce the transfer of entrained mold flux slag and non-metallic particles to the vicinity of solidifying metal near the mold walls, thereby resulting in significantly reduced sliver and related defects. Flow modifier members are placed such that their larger surface is more aligned with the larger dimension of the interior volume of the vessel in which the member is placed. In a particular form, the members may be shaped as rectangular plates and placed substantially parallel to the longer interior wall of the vessel.

1 . A continuous casting system comprising: 
 a mold vessel adapted to receive a flow of molten metal therein, said vessel comprising a plurality of inner surfaces such that an interior volume is defined thereby, said interior volume comprising a width dimension and a thickness dimension that generally corresponds to a respective width and thickness of a slab of metal produced by said system;    a submerged entry nozzle arranged within said interior volume and extending below a molten metal upper surface formed upon introduction of said molten metal into said interior volume, said submerged entry nozzle comprising at least one discharge port adapted to dispense a mixture of gas and said molten metal into said interior volume; and    at least one flow modifier member disposed in said interior volume, said at least one flow modifier member having a height dimension, a width dimension and a thickness dimension such that at least one major surface and at least one minor surface is defined thereby, said at least one major surface defining a larger surface area than said at least one minor surface, said major surface angularly aligned closer to the wider of said width and thickness dimensions of said interior volume.    
   
   
       2 . The system of  claim 1 , wherein said major surface is angularly aligned substantially parallel to the wider of said width and thickness dimensions of said interior volume.  
   
   
       3 . The system of  claim 1 , wherein said at least one flow modifier member extends below said molten metal upper surface.  
   
   
       4 . The system of  claim 1 , wherein said interior volume comprises a rectangular shape.  
   
   
       5 . The system of  claim 4 , wherein each of said at least one flow modifier members is disposed between said submerged entry nozzle and the narrower of said width and thickness dimensions of said interior volume.  
   
   
       6 . The system of  claim 1 , wherein said at least one flow modifier member extends upwardly at least into a flux layer disposed substantially on top of said molten metal upper surface.  
   
   
       7 . The system of  claim 1 , wherein said height, width and thickness dimensions of said at least one flow modifier member are such that said at least one flow modifier member defines a plate.  
   
   
       8 . The system of  claim 7 , wherein said plate is substantially planar.  
   
   
       9 . The system of  claim 1 , wherein said discharge port of said submerged entry nozzle extends below said flow modifier member.  
   
   
       10 . The system of  claim 1 , wherein said at least one discharge port is adapted to dispense said mixture of gas and molten metal into said interior volume at an angle relative to said interior volume width and thickness dimensions.  
   
   
       11 . The system of  claim 1 , wherein said at least one discharge port is adapted to dispense said mixture of gas and molten metal substantially parallel to said interior volume width dimension.  
   
   
       12 . The system of  claim 11 , wherein said at least one flow modifier member comprises a group of flow modifier members, said group configured such that individual flow modifier members in said group are spaced apart from one another substantially along a through-the-thickness axis thereof such that at least a majority of said mixture of gas and molten metal exiting said discharge port flows substantially between said individual flow modifier members in said group.  
   
   
       13 . The system of  claim 12 , wherein said individual flow modifier members within said group are substantially parallel to one another.  
   
   
       14 . A flow modifier member configured for use in a continuous casting system, said flow modifier comprising at least one first surface and at least one second surface, said at least one first surface covering a larger surface area than said at least one second surface, said flow modifier member configured such that upon placement into a substantially rectangular casting vessel defining a width dimension and a thickness dimension such that said with dimension the is greater of the two, said at least one first surface is angularly aligned closer to said width dimension while said at least one second surface is angularly aligned closer to said thickness dimension of said vessel.  
   
   
       15 . The flow modifier member of  claim 14 , wherein said flow modifier member comprises a refractory material.  
   
   
       16 . The flow modifier member of  claim 15 , wherein said refractory material is a ceramic.  
   
   
       17 . The flow modifier member of  claim 14 , further comprising at least one joiner disposed between adjacent ones of said flow modifier members, said at least one joiner sized to block the substantial entirety of space defined between said adjacent ones of said flow modifier members.  
   
   
       18 . A method for controlling the flow of molten metal in a continuous casting system, said method comprising: 
 configuring a vessel to comprise a plurality of walls comprising a height dimension, a width dimension and a thickness dimension to define an interior volume thereby, said width dimension being greater than said thickness dimension;    introducing a mixture of molten metal and gas into said interior volume such that a molten metal upper surface is defined within said interior volume; and    placing a flow modifier member in a location within said interior volume between where said mixture introduction occurs and said wall that defines said thickness dimension, said flow modifier member comprising a height dimension, a width dimension and a thickness dimension such that at least one major surface and at least one minor surface is defined thereby, said at least one major surface defining a larger surface area than said at least one minor surface, said major surface angularly aligned closer to said wall that defines said width dimension such that the velocity of molten metal flowing adjacent said molten metal upper surface is reduced.    
   
   
       19 . The method of  claim 18 , wherein said mixture introduction occurs through a submerged entry nozzle.  
   
   
       20 . The method of  claim 19 , wherein said submerged entry nozzle is angled relative to said interior volume such that said introduced mixture exits said submerged entry nozzle at an angle relative to both said width and thickness dimensions of said interior volume.  
   
   
       21 . The method of  claim 20 , wherein said flow modifier member comprises a pair of flow modifier members, each arranged on opposite sides of said submerged entry nozzle such that each is disposed between said submerged entry nozzle and said walls of said vessel that define said thickness dimension thereof.  
   
   
       22 . The method of  claim 18 , wherein said flow modifier member comprises a plurality of flow modifier members arranged in at least one group such that individual flow modifier members within each said at least one group are spaced apart from one another substantially along a through-the-thickness axis thereof such that at least a majority of said mixture of gas and molten metal exiting said discharge port flows substantially between said individual flow modifier members in said at least one group.