Ultra-thin slab or thick-strip casting

Abstract

A system of twin-roll casting an ultra-thin slab or thick-strip of metal with a liquid core still present inside the hollow shell of the casting as it exits the nip of the opposing counter rotating casting rolls. The wide sides of the cast shell are formed against a recessed casting surface on each roll and the narrow end walls of the shell are formed against the tapered ends of the recessed area so one half of the narrow end wall is formed on each roll and the two halves are joined together at the nip to form the full perimeter of the metal casting. A liquid-cooled copper mold liner provides continued support to each of the four sides of the casting below the twin-rolls and contact with those chilled copper mold liners continues to remove heat from the liquid core of the casting enabling the shell to continue growing in thickness. As the casting exits the mold it will be of adequate thickness to pass through opposing pairs of support rolls below the mold without bulging where water sprays can provide the additional cooling needed for final and complete solidification. A variation of this system uses one or more separating dams to cast different metals or different alloys of the same metal to integrally cast a dual-layer or multi-layer ultra-thin slab or thick strip of metal with a thin metal layer on one or both of the wide and narrow end casting surfaces.

What is claimed is: 
     
         1 . A twin roll continuous casting system, comprising:
 first and second casting rolls that are constructed and arranged to form a casting shell; and   support structure positioned beneath the casting rolls for supporting substantially an entire perimeter of the casting shell as viewed in transverse cross-section.   
     
     
         2 . A twin roll continuous casting system according to  claim 1 , wherein said support structure comprises copper. 
     
     
         3 . A twin roll continuous casting system according to  claim 1 , wherein said support structure is liquid cooled. 
     
     
         4 . A twin roll continuous casting system according to  claim 1 , wherein the support structure is constructed and arranged to facilitate continued solidification of the casting shell. 
     
     
         5 . A twin roll continuous casting system according to  claim 1 , wherein the support structure includes a hard surface coating to minimize wear, the hard surface coating having a hardness that is substantially within a range of about 250 to about 1200 Vickers. 
     
     
         6 . A twin roll continuous casting system according to  claim 1 , wherein the support structure includes a first support surface for supporting a narrow end of the casting shell, and wherein the first support surface is tapered at an upper portion thereof. 
     
     
         7 . A twin roll continuous casting system according to  claim 6 , wherein portions of the first support surface beneath the upper portion are substantially flat. 
     
     
         8 . A twin roll continuous casting system according to  claim 1 , wherein the tapered upper portion of the first support surface terminates at a point. 
     
     
         9 . A twin roll continuous casting system according to  claim 6 , wherein the first support surface forms a narrow gap with respect to one of the first and second casting rolls. 
     
     
         10 . A twin roll continuous casting system according to  claim 1 , wherein the first and second casting rolls are constructed and arranged to form a casting that has a liquid core beneath the casting rolls. 
     
     
         11 . A continuous casting system for making an ultra-thin or thick strip casting, comprising:
 casting roll means for forming a casting shell having pair of narrowfaces and a pair of widefaces, the casting shell having a thickness that is within a range of 0.125 inch to 2 inches and having a liquid core beneath a nip of the casting roll means; and   support structure positioned beneath the casting rolls for supporting substantially an entire perimeter of the casting shell as viewed in transverse cross-section.   
     
     
         12 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein said support structure comprises copper. 
     
     
         13 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein said support structure is liquid cooled. 
     
     
         14 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein the support structure is constructed and arranged to facilitate continued solidification of the casting shell. 
     
     
         15 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein the support structure includes a hard surface coating to minimize wear, the hard surface coating having a hardness that is substantially within a range of about 250 to about 1200 Vickers. 
     
     
         16 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein the support structure includes a first support surface for supporting a narrow end of the casting shell, and wherein the first support surface is tapered at an upper portion thereof. 
     
     
         17 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 16 , wherein portions of the first support surface beneath the upper portion are substantially flat. 
     
     
         18 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 11 , wherein the tapered upper portion of the first support surface terminates at a point. 
     
     
         19 . A continuous casting system for making an ultra-thin or thick strip casting according to  claim 16 , wherein the first support surface forms a narrow gap with respect to one of the first and second casting rolls.