Amorphous or glassy alloy surfaced rolls for the continuous casting of metal strip

Abstract

A method for continuously casting metal strip is provided in which a casting pool of molten metal is found in contact with a moving casting surface such that metal solidifies from the pool onto the moving casting surface, wherein the casting surface is provided by a solid coating on a heat conductive body and the coating is formed of a material such that the wetting angle of said molten metal on the casting surface is less than 40° and which has a melting temperature greater that the temperature of the casting surface during metal solidification.

1 . A method for continuously casting metal strip of the kind in which a casting pool of molten metal is formed in contact with a moving casting surface such that metal solidifies from the pool onto the moving casting surface, wherein the casting surface is provided by a solid coating on a heat conductive body and the coating is formed of a material such that the wetting angle of said molten metal on the casting surface is less than 40° and which has melting temperature greater than the temperature of the casting surface during metal solidification.  
     
     
         2 . A method as claimed in  claim 1 , wherein the coating is formed of a material such that the wetting angle of the molten metal on the casting surface is less than 20°.  
     
     
         3 . A method as claimed in  claim 1  or  claim 2 , wherein the coating surface has an Arithmetic Mean Roughness Value (R a ) of less than 10 microns.  
     
     
         4 . A method as claimed in any one of the preceding claims, wherein the molten metal is molten steel.  
     
     
         5 . A method as claimed in  claim 4 , wherein the steel solidifies into a single phase solid structure on the casting surface.  
     
     
         6 . A method as claimed in any one of the preceding claims, wherein the coating material is at least partially amorphous.  
     
     
         7 . A method as claims in  claim 6 , wherein the coating material is substantially totally amorphous.  
     
     
         8 . A method as claimed in any one of the preceding claims, wherein the coating material is comprised of an alloy of two metals.  
     
     
         9 . A method as claimed in  claim 8 , wherein one of said two metals is phosphorous.  
     
     
         10 . A method as claimed in  claim 9 , wherein the other of said two metals is nickel.  
     
     
         11 . A method as claimed in any one of  claims 8  to  10 , wherein said alloy is a substantially eutectic alloy.  
     
     
         12 . A method as claimed in any one of the preceding claims, wherein the molten metal has a substantially eutectic composition.  
     
     
         13 . A method as claimed in any one of the preceding claims, wherein the heat conductive body is a copper or copper alloy body.  
     
     
         14 . A method for continuously casting steel strip of the kind in which a casting pool of molten steel is formed in contact with a moving casting surface such that steel solidifies from the casting pool onto the moving casting surface, wherein the casting surface is provided by a solid coating on a heat conductive body and the coating is formed of a material such that the wetting angle of the molten metal on the casting surface is less than 40° and which has a melting temperature greater than the temperature of the casting surface during metal solidification, and wherein the steel solidifies into a single phase solid structure on the casting surface which phase does not transform before the strip has left the casting surface.  
     
     
         15 . A method as claimed in  claim 14 , wherein said steel has a carbon equivalent content of not more than 0.53% by weight and said single phase structure comprises dendrites of solid austenite.  
     
     
         16 . A method as claimed in  claim 15 , wherein the steel has a substantially peritectic composition.  
     
     
         17 . A method as claimed in  claim 16 , wherein the steel has a carbon content of about 0.13% by weight.  
     
     
         18 . A method as claimed in any one of  claims 14  to  17 , wherein the coating material is comprised of an amorphous alloy of two metals.  
     
     
         19 . A method as claimed in  claim 18 , wherein one of the two metals is phosphorous.  
     
     
         20 . A method as claimed in  claim 19 , wherein the coating is a nickel-phosphorous alloy containing about 10% phosphorous.  
     
     
         21 . A method as claimed in any one of  claims 14  to  20 , wherein the heat conductive body is a copper or copper alloy body.  
     
     
         22 . A method as claimed in any one of  claims 14  to  21 , wherein the moving casting surface is one of a pair of such surfaces being the surfaces of a pair of casting rolls forming a nip between them, the casting pool being supported on the casting rolls above the nip and the strip being delivered downwardly from the nip with said single phase solid structure.  
     
     
         23 . A method for continuously casting metal strip of the kind in which a casting pool of molten metal is formed in contact with a moving casting surface such that metal solidifies from the casting pool onto the moving casting surface, wherein the metal is of peritectic composition, the casting surface is provided by a solid coating on a heat conductive body and the coating is formed of a material such that the wetting angle of the molten metal on the casting surface is less than 40° and which has a melting temperature greater than the temperature of the casting surface during metal solidification, and wherein the metal solidifies into a single phase solid structure on the casting surface which phase does not transform before the strip has left the casting surface.  
     
     
         24 . Apparatus for continuously casting metal strip comprising a casting roll having a casting surface to contact a casting pool of molten metal and means to cool the casting surface of the casting roll to cause metal to solidify thereon, wherein the roll surface is formed by a solid coating on a heat conductive body of the roll which coating is comprised of a substantially amorphous alloy of two metals.  
     
     
         25 . Apparatus as claimed in  claim 24 , wherein one of the two metals is phosphorous.  
     
     
         26 . Apparatus as claimed in  claim 25 , wherein the coating alloy is a nickel-phosphorous alloy.  
     
     
         27 . Apparatus as claimed in  claim 26 , wherein the coating alloy contains about 10% phosphorous.  
     
     
         28 . A casting roll comprising a heat conductive cylindrical roll body covered by a solid coating defining a cylindrical metal casting surface, wherein the coating is comprised of a substantially amorphous alloy of two metals.  
     
     
         29 . A casting roll as claimed in  claim 28 , wherein one of the two metals is phosphorous.  
     
     
         30 . A casting roll as claimed in  claim 29 , wherein the casting alloy is a nickel-phosphorous alloy.  
     
     
         31 . A casting roll as claimed in  claim 30 , wherein the coating alloy contains about 10% phosphorous.  
     
     
         32 . A cast steel strip produced by continuous casting from a steel having a carbon equivalent content of not more than 0.53% by weight and having a microstructure resulting from direct solidification from molten metal into austenite prior to subsequent low temperature transformation.  
     
     
         33 . A cast steel strip as claimed in  claim 32 , wherein the steel has a substantially peritectic composition.  
     
     
         34 . A cast steel strip as claimed in  claim 33 , wherein the steel has a carbon content of about 0.13% by weight.