Method for balancing a flow of liquid steel into a casting mold and continuous casting system for liquid steel

Abstract

This method for balancing a flow of liquid steel into a casting mold, in which the steel is introduced into the casting mold from a tundish through a protective nozzle which opens below the steel level into the casting mold, comprises the following steps: a) acquiring a set of characteristics of the flow in the casting mold, b) comparing the flow characteristics acquired in the previous step with a predefined model and determining the adjustment actions to take in order to balance the flow, and c) adjusting the flow.

1 . A method for balancing a flow of liquid steel in a casting mold ( 12 ) having a longitudinal axis, wherein the steel is introduced into the casting mold ( 12 ) from a tundish ( 8 ) through a protective nozzle ( 11 ) opening below the level of steel in the casting mold ( 12 ), comprising the following steps:
 a) acquisition of a set of characteristics of the flow in the casting mold ( 12 ),   b) comparison of the flow characteristics acquired in the preceding step against a predetermined model and determination of the adjustment actions to be taken in order to balance the flow, and   c) adjustment of the flow;   wherein the flow adjustment is performed by effecting a relative movement between the nozzle ( 11 ) and the casting mold ( 12 ).   
     
     
         2 . The method as claimed in the preceding claim, wherein steps a) to c) are repeated continuously during the casting operations. 
     
     
         3 . The method as claimed in the preceding claim, wherein the flow characteristics are obtained by an analysis of the thermal characteristics of the steel in the casting mold ( 12 ). 
     
     
         4 . The method as claimed in the preceding claim, wherein the casting mold ( 12 ) has a pouring axis and is of the type consisting of an assembly of metal plates ( 22 ) backed by cooling devices ( 14 ) which are configured to allow the metal plates ( 22 ) to be cooled by the circulation of a cooling fluid, comprising an optical fiber ( 28 ), comprising a plurality of Bragg filters ( 34 ), extending in a wall of at least one of said plates ( 22 ), the optical fiber ( 28 ) extending in a direction not parallel to the pouring axis of the casting mold ( 12 ). 
     
     
         5 . The method as claimed in the preceding claim, further comprising the following steps:
 measurement of the temperature of at least one wall of the casting mold ( 12 ) by means of the optical fiber ( 28 ), and   adjustment of the flow.   
     
     
         6 . (canceled) 
     
     
         7 . The method as claimed in  claim 1 , wherein the relative movement between the nozzle ( 11 ) and the casting mold ( 12 ) is effected in a direction parallel to the longitudinal axis of the casting mold ( 12 ). 
     
     
         8 . The method as claimed in  claim 1 , wherein the relative movement between the nozzle ( 11 ) and the casting mold ( 12 ) is effected by angularly offsetting the nozzle about the longitudinal axis of the casting mold ( 12 ). 
     
     
         9 . The method as claimed in  claim 1 , wherein the relative movement between the nozzle ( 11 ) and the casting mold ( 12 ) is effected both in a direction parallel to the longitudinal axis of the casting mold ( 12 ) and by angularly offsetting the nozzle about the longitudinal axis of the casting mold ( 12 ). 
     
     
         10 . The method as claimed in  claim 1 , wherein the nozzle ( 11 ) is secured to the tundish ( 8 ) and the relative movement between the nozzle ( 11 ) and the casting mold ( 12 ) is achieved by moving the tundish ( 8 ) with respect to the casting mold ( 12 ). 
     
     
         11 . A system for the continuous casting of liquid steel from a tundish to a continuous casting mold, comprising:
 a tundish ( 8 ),   a casting mold ( 12 ) of the type consisting of an assembly of metal plates ( 22 ) backed by cooling devices ( 14 ) which are configured to allow the metal plates ( 22 ) to be cooled by the circulation of a cooling fluid, comprising an optical fiber ( 28 ), comprising a plurality of Bragg filters ( 34 ), extending in a wall of at least one of said plates ( 22 ), the casting mold having a pouring axis, the optical fiber ( 28 ) extending in a direction not parallel to the pouring axis of the casting mold ( 12 ),   a protective nozzle ( 11 ) the lower end of which opens below the level of the steel in the casting mold ( 12 ) while the steel is being poured, the nozzle ( 11 ) being secured to the tundish ( 8 ),   an emitter-receiver designed to send light into the optical fiber ( 28 ) and to receive the light reflected and/or transmitted by the optical fiber ( 28 ),   a processor designed to:
 a) convert the data pertaining to the reflected and/or transmitted light received by the emitter-receiver into information pertaining to the flow in the casting mold ( 12 ), 
 b) compare this information against a predefined model, 
 c) determine the adjustment actions to be taken in order to balance the flow, 
 d) emit a control signal, 
   adjustment means ( 36 ) designed to receive the control signal and to adjust the flow of the steel in the casting mold ( 12 ) as a function of the control signal by effecting a relative movement between the nozzle and the casting mold.   
     
     
         12 . The system as claimed in the preceding claim, wherein the adjustment means ( 36 ) comprise a tundish car.