Electric arc melting facility and method for producing molten metal by using the electric arc melting facility

Abstract

An electric arc melting facility includes a melting chamber configured to melt a source iron therein by electric arc discharge generated from an electrode, and a source iron feeder configured to continuously feed the source iron to the melting chamber. The facility further includes a state change detector configured to detect a state change of the melting chamber when the electric arc discharge is generated from the electrode, and a controller configured to adjust a feed rate at which the source iron feeder feeds the source iron to the melting chamber, based on a detection result of the state change detectors.

1 . An electric arc melting facility comprising:
 a melting chamber configured to melt a source iron therein by electric arc discharge generated from an electrode; and   a source iron feeder configured to continuously feed the source iron to the melting chamber,   wherein the electric arc melting facility further comprises:   a state change detector configured to detect a state change of the melting chamber when the electric arc discharge is generated from the electrode; and   a controller configured to adjust a feed rate at which the source iron feeder feeds the source iron to the melting chamber, based on a detection result of the state change detector,   wherein the state change detector is configured to detect a variation in at least one of amounts of harmonics contained in current and voltage applied to the electrode, as the state change of the melting chamber.   
     
     
         2 . The electric arc melting facility according to  claim 1 , wherein the state change detector is configured to detect a variation in harmonic distortion ratio as the variation in at least one of amounts of harmonics. 
     
     
         3 - 6 . (canceled) 
     
     
         7 . A method for producing molten metal while melting the source iron by using the electric arc melting facility according to  claim 1 , the method comprising:
 a state change detecting step of detecting a state change of the melting chamber when the electric arc discharge is generated; and   a feed rate adjusting step of adjusting a feed rate at which the source iron is fed to the melting chamber, based on a detection result of the state change detecting step.   
     
     
         8 . The method for producing the molten metal, according to  claim 7 , wherein the method further comprises a feed-power adjusting step of adjusting an electric power applied to the electrode, in addition to the feed rate adjusting step of adjusting the feed rate, based on a detection result of the state change detecting step. 
     
     
         9 . The method for producing the molten metal according to  claim 7 , wherein the source iron feeder includes a preheating chamber directly connected to the melting chamber and configured to preheat the source iron therein, and a pushing device disposed at a lower side of the preheating chamber and configured to move the source iron from the preheating chamber toward the melting chamber, and the method further comprises:
 a source iron feeding step of driving the pushing device to feed the source iron from the preheating chamber to the melting chamber;   a source iron preheating step of introducing exhaust gas generated in the melting chamber into the preheating chamber to preheat the source iron in the preheating chamber; and   a source iron melting step of melting the source iron with heat generated by the electric arc discharge in the melting chamber while feeding the source iron to the preheating chamber so as to maintain a state in which the source iron is present in the preheating chamber and the melting chamber.   
     
     
         10 . The method for producing the molten metal according to  claim 8 , wherein the source iron feeder includes a preheating chamber directly connected to the melting chamber and configured to preheat the source iron therein, and a pushing device disposed at a lower side of the preheating chamber and configured to move the source iron from the preheating chamber toward the melting chamber, and the method further comprises:
 a source iron feeding step of driving the pushing device to feed the source iron from the preheating chamber to the melting chamber;   a source iron preheating step of introducing exhaust gas generated in the melting chamber into the preheating chamber to preheat the source iron in the preheating chamber; and   a source iron melting step of melting the source iron with heat generated by the electric arc discharge in the melting chamber while feeding the source iron to the preheating chamber so as to maintain a state in which the source iron is present in the preheating chamber and the melting chamber.   
     
     
         11 . The electric arc melting facility according to  claim 1 , wherein the controller is configured to adjust an electric power applied to the electrode, in addition to the feed rate, based on a detection result of the state change detector. 
     
     
         12 . The electric arc melting facility according to  claim 1 , wherein the source iron feeder includes a preheating chamber directly connected to the melting chamber and configured to preheat the source iron therein, and a pushing device disposed at a lower side of the preheating chamber and configured to move the source iron from the preheating chamber toward the melting chamber.