Crystallizer for continuous casting and method for its production

Abstract

Crystallizer for continuous casting comprising a tubular body ( 11 ) having at least one wall ( 12 ) which defines a through longitudinal casting cavity ( 13 ) and a plurality of longitudinal grooves ( 14 ) made at least on one part of the wall ( 12 ) and open toward the outside thereof. A covering binding ( 15 ) is associated to the external surface of the wall ( 12 ) to close the longitudinal groves ( 14 ) and thus obtain corresponding cooling channels ( 17 ) configured to make a cooling liquid flow inside them.

1 . Crystallizer for continuous casting, comprising:
 a tubular body having at least one wall which defines a through longitudinal casting cavity and a plurality of longitudinal grooves made at least on one part of said at least one wall and open toward the outside thereof,   wherein a covering binding, comprising one or more overlapping layers of fiber material impregnated with a polymer material, which define one or more bands, is wound around an external surface of said tubular body and irremovably attached thereto by a polymerization thereof, so as to create an indivisible whole between the at least one wall with the longitudinal grooves and the covering binding,   wherein the covering binding is in direct contact with one of: the external surface of the at least one wall and closes the longitudinal grooves, or at least one of: a metal layer, a lamina, or a plate that in its turn is in direct contact with the external surface of the at least one wall and closes the longitudinal grooves, to define a corresponding plurality of cooling channels,   wherein the crystallizer has an internal conicity, wherein the covering binding is wound tightly around the external surface of the tubular body in a direction mainly transverse to its longitudinal direction limiting the deformation and movement of the at least one wall to maintain the internal conicity, while allowing longitudinal dilation due to heat phenomena,   wherein said covering binding has a variable thickness along the longitudinal extension of said tubular body to define at least an upper portion, substantially comprising the meniscus area during the casting, defining a thickened zone having a thickness comprised between 1.1-1.25 the thickness of a non-thickened zone in a lower portion of the tubular body.   
     
     
         2 . Crystallizer as in  claim 1 , wherein said one or more bands are made using at least one fiber impregnated, or pre-impregnated, with polymer material. 
     
     
         3 . Crystallizer as in  claim 1 , wherein said fiber is chosen from a group comprising carbon fibers, glass fibers, aramid fibers or combinations thereof, and said polymer is chosen from a group comprising polyamide, epoxy or polyester resins. 
     
     
         4 . Method to obtain a crystallizer for continuous casting, comprising:
 a step of making a tubular body having at least one wall which defines a through longitudinal casting cavity and a plurality of longitudinal grooves made at least on one part of an external surface of said at least one wall and open toward the outside thereof,   a step in which a covering binding, comprising one or more overlapping layers of fiber material impregnated with a polymer material, which define one or more bands, is wound around said external surface of said at least one wall and then said polymer material is polymerized in order to solidly attach said covering binding to said wall, in which the polymerization of said polymer material comprises:   a curing step during which said crystallizer is heated to a temperature comprised between 30° C. and 120° C. and kept at this temperature for a period comprised between 20 and 200 minutes, and   a post-curing step during which said crystallizer is heated to a temperature comprised between 80° C. and 200° C. and kept at this temperature for a period comprised between 60 minutes and 1200 minutes.   
     
     
         5 . Method as in  claim 4 , wherein, in said curing step, said crystallizer is heated to a temperature comprised between 70° C. and 100° C. and kept at this temperature for a period comprised between 120 minutes and 360 minutes. 
     
     
         6 . Method as in  claim 4 , wherein, in said post-curing step, said crystallizer is heated to a temperature comprised between 100° C. and 150° C. and kept at this temperature for a period at least about 360 minutes. 
     
     
         7 . Method as in  claim 4 , wherein, before the winding of said one or more overlapping layers of fiber material, there is a step of filling said longitudinal grooves with disposable material, to deposit a metal layer on the external surface of said at least one wall by means of electrolytic deposition techniques, in order to close said longitudinal grooves, and a further step of removing said disposable material from said longitudinal grooves so as to define corresponding cooling channels. 
     
     
         8 . Method as in  claim 4 , wherein, before the winding of said one or more overlapping layers of fiber material, there is a step of closing said longitudinal grooves with at least one lamina made of a fiber-reinforced polymer material to define a plurality of cooling channels, and wherein, during said winding, said fiber material is wound around and in direct contact with said lamina made of fiber-reinforced polymer material. 
     
     
         9 . Method as in  claim 4 , wherein, before the winding of said one or more overlapping layers of fiber material, there is a step of closing said longitudinal grooves with at least a plate associated to the external surface of said at least one wall so as to define a corresponding plurality of cooling channels. 
     
     
         10 . Method as in  claim 4 , wherein said fiber material is wound around said wall at a winding angle comprised between 0° and 10°, preferably between 0° and 5°, with respect to the perpendicular to the axis of longitudinal development of the crystallizer. 
     
     
         11 . Method as in  claim 4 , wherein said covering binding comprises a band made using at least a fiber impregnated or pre-impregnated with glue or polymer resin, said covering binding having a volumetric ratio of fibers of 60%, and glue or polymer resin of 40%. 
     
     
         12 . Method as in  claim 4 , wherein during the winding of said fiber material, fibers making up said covering binding are wound at a controlled tension between 1N and 50N. 
     
     
         13 . Method as in  claim 4 , wherein said covering binding is applied using the filament winding technique.