Method and system for producing steel having low nitrogen content

Abstract

A method of introducing a denitrogenizing flux material into a container of molten metal includes steps of providing a wire-like vector that has an inner core of flux material and an outer layer that is used to contain the inner core, and using a wire feed machine to introduce the wire-like vector into a container of molten metal. In comparison with conventional top slag removal techniques, this process permits the material from which the inner core is made to be injected into the container of molten metal at a speed and direction that promotes a controlled mixing of the flux material and the molten metal.

What is claimed is:  
     
         1 . A method of introducing a denitrogenizing flux to an amount of molten metal, comprising steps of: 
 (a) encasing the denitrogenizing flux with an outer layer of a metallic material that has a melting point that is beneath the temperature of the amount of molten metal; and    (b) introducing the flux so encased into the molten metal, whereby the outer layer will melt, thereby introducing the flux into the molten metal.    
     
     
         2 . A method according to    claim 1   , wherein step (a) is performed by encasing the flux in an elongated, tube-like hollow cladding of metallic material, thereby forming a wire-like vector.  
     
     
         3 . A method according to    claim 2   , wherein step (b) is performed by introducing the wire-like vector into the molten metal by using a conventional wire feeding machine.  
     
     
         4 . A method according to    claim 1   , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).  
     
     
         5 . An article for introducing a denitrogenizing flux to an amount of molten metal, comprising: 
 an outer layer of a metallic material that has a melting point that is beneath the anticipated temperature of the amount of molten metal; and    a denitrogenizing flux that is encased within the molten metal, whereby the outer layer will melt after the article has been introduced into the molten metal for a predetermined period of time, thereby permitting introduction of the denitrogenizing flux into the molten metal at a depth below the top surface of the molten metal.    
     
     
         6 . An article according to    claim 5   , wherein said outer layer encases the nonmetallic substance in an elongated, tube-like hollow cladding of metallic material, thereby forming a wire-like vector.  
     
     
         7 . An article according to    claim 5   , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).  
     
     
         8 . A method of denitrogenizing an amount of molten metal, comprising steps of: 
 (a) providing an amount of molten metal; and    (b) introducing a denitrogenizing flux into the molten metal in such a way that the flux becomes exposed to the molten metal at a location that is at a depth that is substantially below the top surface of the molten metal, thereby promoting more efficient mixing of the flux into the molten metal.    
     
     
         9 . A method according to    claim 8   , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).  
     
     
         10 . A method of introducing a denitrogenizing flux to an amount of molten metal, comprising steps of: 
 (a) supplying an amount of denitrogenizing flux into a lance assembly of the type that includes a nozzle that is constructed and arranged to be immersed in molten metal; and    (b) using the lance assembly to introduce the flux into the molten metal.    
     
     
         11 . A method according to    claim 10   , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).