Method and device for controlling the temperature of steel from the surface of the bath of a continuous casting installation up to the furnace tap

Abstract

The invention relates to a method, which is used in the area of secondary metallurgy ( 4 ) in its entirety with a final temperature-determining process step ( 4.1 ) such as a ladle furnace, for controlling the temperature of steel from the surface of the bath of a continuous casting ingot mold ( 1 ) up to the furnace tap ( 5 ) of a steel producing process. According to the invention, the temperature of the steel in the surface of the bath is controlled based on the equation T ML =T LI +X° C. (X= 5-15 ° C. and while respecting the same such that a jump in temperature ( 9 ) between the surface of the bath in the ingot mold ( 1 ) and a distributor ( 3 ) is detected according to the pouring rate ( 6 ) for a predetermined billet size. In addition, the ladle history ( 7 ) with regard to the time intervals, such as ladle full, ladle empty and ladle state, such as ladle bricking up and ladle age is detected as well as a jump in the temperature of steel between the distributor ( 3 ) and the last ladle furnace temperature (LF-ex).

1 . Method for controlling the temperature of the steel in a steel production process between the meniscus of a continuous casting mold ( 1 ) and the tapping of the furnace ( 5 ) and thus over the entire course of secondary metallurgical processing ( 4 ) with a final temperature-determining process stage ( 4 . 1 ) such as a ladle furnace, characterized in that 
 the temperature of the steel at the meniscus of T ML =T li +X° C. (X=5-15° C.) is controlled and maintained under consideration of the fact that there is a discontinuity ( 9 ) in the temperature between the meniscus in the mold ( 1 ) and a tundish ( 3 ) as a function of the casting speed ( 6 ) for a strand of predetermined format; and in that    the ladle history ( 7 ), comprising the time periods “ladle full” and “ladle empty”; the ladle conditions such as the ladle lining and the age of the ladle; and the discontinuity in the temperature of the steel between the tundish ( 3 ) and the last ladle furnace temperature (LF-ex) is recorded.    
     
     
         2 . Method according to  claim 1 , characterized in that the ladle history ( 7 ) is recorded in a time-differentiated manner by an individual ladle identification system ( 8 ), which is installed in the ladle cycle.  
     
     
         3 . Method according to  claim 1  or  claim 2 , characterized in that the natural radiation of the ladle skin, which is relatively hot in comparison with the ambient temperature, is used as a means of detecting the individual ladles.  
     
     
         4 . Method according to one of claims  1 - 3 , characterized in that the ladle identification system ( 8 ) differentiates at least between the “ladle full” time, the “ladle empty” time, and the “ladle with new lining” time.  
     
     
         5 . Method according to one of claims  1 - 4 , characterized in that the history of the tundish is differentiated with respect to the tundish preheating temperature, the tundish lining, the tundish drying time, and the tundish service life data to allow for the more accurate determination of temperature discontinuities between the meniscus and the tundish and between the tundish and the ladle furnace (LF-ex).  
     
     
         6 . Device for controlling the temperature of the steel in a steel production process between the meniscus of a continuous casting mold ( 1 ) and the tapping of the furnace ( 5 ) and thus over the entire course of secondary metallurgical processing ( 4 ) with a final temperature-determining process stage ( 4 . 1 ) such as a ladle furnace, especially for implementing the method according to  claim 1 , characterized in that measuring means ( 1 . 2  or  4 . 3 ) are provided for detecting the temperature of the steel at the meniscus of the mold ( 1 ) in a temperature window ( 2 . 1 ) of T ML =T li +X° C. (X=5-15° C.) or for detecting the temperature of the steel in the tundish ( 3 ) from TT-ideal=T °   li +10° C. ( 10 . 1 ) or TT-real=T °   li +10° C.±5° C. ( 10 . 2 ) as a function of the casting speed ( 6 ), measuring means ( 3 .n) also being provided for detecting the tundish preheating time ( 3 . 2 . 2 ) and the tundish preheating temperature ( 3 . 2 . 1 ); in that a ladle identification system ( 8 ) provided inside the ladle cycle ( 7 . 4 ) or the ladle turnover ( 7 . 4 . 1 ) records the ladle history ( 7 ), where the measuring means are connected to a computer ( 4 . 4 ), which uses the measurement values to determine on-line the temperature discontinuities ( 9  and  4 . 1 . 1 ) between the meniscus ( 2 ) and the tundish ( 3 ) and between the tundish ( 3 ) and the ladle furnace ( 4 . 1 ), respectively.  
     
     
         7 . Device according to  claim 6 , characterized in that the ladle identification system ( 8 ) works with a coded metal plate ( 8 . 1 . 1 ) and makes use of the natural radiation of the ladle, where the metal plate is mounted a certain distance away from the outside surface of the ladle ( 4 . 3 ) and conveys the time and position data of each individual ladle ( 8 . 1 ) (ladle as individual entity) to at least one radiation-measuring device ( 8 . 1 . 2 ) installed in the ladle cycle ( 7 . 4 . 1 ).  
     
     
         8 . Device according to  claim 6  or  claim 7 , characterized in that the ladle detection system ( 8 ) is designed to detect at least the “ladle full” time ( 7 . 1 ), the “ladle empty” time ( 7 . 2 ), and the “ladle with a new lining” time.