Continuous casting rolls and method of using

Abstract

A roll for use in a continuous casting machine includes a roll body that is constructed and arranged to be mounted for rotation in a guide segment area of a continuous casting machine, and a generally cylindrical outer surface on the roll body. Preferably, the outer surface is fabricated at least in part from an age-hardenable nickel-based alloy that includes, in weight percent, up to 0.3% carbon, about 5% to about 12% chromium, and about 10% to about 30% molybdenum. The roll exhibits superior high temperature strength and stability, low thermal expansion, and superior oxidation resistance at temperatures that are typical during operation in a continuous casting machine. A process of making a metal casting using such a roll is also disclosed.

What is claimed is:  
     
         1 . A roll for use in a continuous casting machine, comprising: 
 a roll body that is constructed and arranged to be mounted for rotation; and    a generally cylindrical outer surface on said roll body, said outer surface comprising an age-hardenable nickel-based alloy comprising, in weight percent,    up to 0.3% carbon,    about 5% to about 12% chromium, and    about 10% to about 30% molybdenum.    
     
     
         2 . A roll according to  claim 1 , wherein said nickel based alloy comprises about 7% to about 9% chromium.  
     
     
         3 . A roll according to  claim 1 , wherein said nickel based alloy comprises about 10% to about 26% molybdenum.  
     
     
         4 . A roll according to  claim 1 , wherein said nickel-based alloy consists essentially of up to 0.3% carbon, 5% to 12% chromium, 10% to 30% molybdenum, 22% to 40% molybdenum plus tungsten, 1% maximum aluminum, trace to 0.015% boron, 5% maximum iron, 2% maximum manganese, 1.2% maximum silicon, 0.1% maximum rare earth metals, balance nickel plus normal impurities wherein the ratio of Mo+W:Cr is between 2:1 and 7:1 to provide a favorable combination of properties and wherein the chromium plus molybdenum content exceeds 3:1 to obtain optimum ordering characteristics.  
     
     
         5 . A roll according to  claim 1 , wherein said roll body comprises a sleeve, and said outer surface is defined on said sleeve.  
     
     
         6 . A roll according to  claim 1 , wherein said nickel-based alloy is deposited on said outer surface by a cladding process.  
     
     
         7 . A process of making a metal casting, comprising steps of: 
 (a) introducing molten metal into a first end of continuous casting mold;    (b) withdrawing a newly-formed casting from a second end of the continuous casting mold; and    (c) guiding the newly formed casting with a plurality of continuous casting rolls, and wherein at least one of the rolls has an outer surface that includes an age-hardenable nickel-based alloy comprising, in weight percent, up to 0.3% carbon, about 5% to about 12% chromium, and about 10% to about 30% molybdenum.    
     
     
         8 . A process according to  claim 7 , wherein step (c) is performed with a nickel based alloy that comprises about 7% to about 9% chromium.  
     
     
         9 . A process according to  claim 7 , wherein step (c) is performed with a nickel based alloy that comprises about 10% to about 26% molybdenum.  
     
     
         10 . A process according to  claim 7 , wherein step (c) is performed with roll with a nickel-based alloy that consists essentially of up to 0.3% carbon, 5% to 12% chromium, 10% to 30% molybdenum, 22% to 40% molybdenum plus tungsten, 1% maximum aluminum, trace to 0.015% boron, 5% maximum iron, 2% maximum manganese, 1.2% maximum silicon, 0.1% maximum rare earth metals, balance nickel plus normal impurities wherein the ratio of Mo+W:Cr is between 2:1 and 7:1 to provide a favorable combination of properties and wherein the chromium plus molybdenum content exceeds 3:1 to obtain optimum ordering characteristics.  
     
     
         11 . A roll for use in a continuous casting machine, comprising: 
 a roll body that is constructed and arranged to be mounted for rotation; and    a generally cylindrical outer surface on said roll body, said outer surface comprising an age-hardenable Ni—Mo—Cr alloy in which the weight percent of Mo is greater than the weight percent of Cr.    
     
     
         12 . A roll according to  claim 11 , wherein said roll body comprises a sleeve, and said outer surface is defined on said sleeve.  
     
     
         13 . A roll according to  claim 11 , wherein said age-hardenable Ni—Mo—Cr alloy is deposited on said cuter surface by a cladding process.  
     
     
         14 . A process of reconditioning a roll for a continuous casting machine, comprising steps of: 
 (a) removing a continuous casting roll from a continuous casting machine;    (b) stripping degraded material from a surface of the roll;    (c) applying a new outer surface to the roll, said outer surface comprising an age-hardenable Ni—Mo—Cr alloy in which the weight percent of Mo is greater than the weight percent of Cr; and    (d) installing the roll into a continuous casting machine.    
     
     
         15 . A process according to  claim 14 , wherein step (c) comprises applying the alloy by cladding.  
     
     
         16 . A process according to  claim 14 , wherein step (c) comprises applying the alloy by securing a sleeve to the roll.  
     
     
         17 . A process according to  claim 14 , wherein step (c) comprises applying the alloy by thermal spray deposition.