Casting thin strip and delivery nozzle therefor

Abstract

A method of casting metal strip and equipment therefor where an elongated metal delivery nozzle extending along in a continuous caster with at least one segment having a main portion adapted to deliver molten metal in the casting pool above the nip along the metal delivery nozzle and an end portion adjacent side dams having a reservoir portion with first and second passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells are forming on the casting rolls. The first passages are adapted to deliver molten metal shallowly into the casting pool adjacent the side dams, and the second passages adapted to deliver molten metal deeper into the casting pool than the first passages adjacent the side dams to inhibit formation of skulls during the formation of the cast strip during a casting campaign.

1 . A method of casting metal strip comprising:
 (a) assembling a pair of casting rolls laterally disposed to form a nip between them and between side dams adapted to maintain a molten metal pool supported by the casting rolls,   (b) assembling an elongated metal delivery nozzle extending along and above the nip with at least one segment having a main portion adapted to deliver molten metal in the casting pool along the metal delivery nozzle and an end portion adjacent side dams having a reservoir portion having first and second passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells are forming on the casting rolls, the first passages adapted to deliver molten metal shallowly into the casting pool adjacent the side dams and the second passages adapted to deliver molten metal deeper into the casting pool than the first passages adjacent the side dams,   (c) introducing molten metal through the elongated metal delivery nozzle to form a casting pool of molten metal supported on the casting rolls above the nip, and through the first and second passages in the reservoir portion in the end portions into the casting pool, and   (d) counter rotating the casting rolls to deliver cast strip downwardly from the nip.   
     
     
         2 . The method of casting metal strip as claimed in  claim 1  where the first and second passages of the reservoir portion are substantially parallel. 
     
     
         3 . The method of casting metal strip as claimed in  claim 1  where the first and second passages of the reservoir portion are between 5 and 30 millimeters apart. 
     
     
         4 . The method of casting metal strip as claimed in  claim 1  where the first and second passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         5 . The method of casting metal strip as claimed in  claim 1  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion. 
     
     
         6 . The method of casting metal strip as claimed in  claim 1  where dual first and second passages are provided in each reservoir portion of the metal delivery nozzle. 
     
     
         7 . The method of casting metal strip as claimed in  claim 6  where the first and second passages of the reservoir portion are substantially parallel. 
     
     
         8 . The method of casting metal strip as claimed in  claim 6  where the first and second passages of the reservoir portion are between 5 and 30 millimeters apart. 
     
     
         9 . The method of casting metal strip as claimed in  claim 6  where the first and second passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         10 . The method of casting metal strip as claimed in  claim 6  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion of the delivery nozzle. 
     
     
         11 . A metal delivery apparatus for casting metal strip comprising at least one elongated segment having a main portion adapted to deliver molten metal in the casting pool along the metal delivery nozzle and an end portion adjacent side dams having a reservoir portion having first and second passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells form on the casting rolls, the first passages adapted to deliver molten metal shallowly into the casting pool adjacent the side dams and the second passages adapted to deliver molten metal deeper into the casting pool than the first passages adjacent the side dams. 
     
     
         12 . The metal delivery apparatus for casting metal as claimed in  claim 11  where the first and second passages of the reservoir portion are substantially parallel. 
     
     
         13 . The metal delivery apparatus for casting metal strip as claimed in  claim 11  where the first and second passages of the reservoir portion are between 5 and 30 millimeters apart. 
     
     
         14 . The metal delivery apparatus for casting metal strip as claimed in  claim 11  where the first and second passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         15 . The metal delivery apparatus for casting metal strip as claimed in  claim 11  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion of the metal delivery apparatus. 
     
     
         16 . The metal delivery apparatus for casting metal strip as claimed in  claim 11  where dual first and second passages are provided in each reservoir portion of the metal delivery nozzle. 
     
     
         17 . The metal delivery apparatus for casting metal strip as claimed in  claim 16  where the first and second passages of the reservoir portion are substantially parallel. 
     
     
         18 . The metal delivery apparatus for casting metal strip as claimed in  claim 16  where the first and second passages of the reservoir portion are between 5 and 30 millimeters apart. 
     
     
         19 . The metal delivery apparatus for casting metal strip as claimed in  claim 16  where the first and second passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         20 . The metal delivery apparatus for casting metal strip as claimed in  claim 16  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion of the delivery apparatus.