Casting steel strip

Abstract

A method of producing steel strip by continuous casting and a twin roll caster in which a scrap receptacle is provided for collecting scrap. The scrap receptacle is positioned in a scrap receiving position and may be changed out as desired with a replacement receptacle with little or no interruption to casting operations. In the receiving position the scrap receptacle may form a part of a sealed casting enclosure. The scrap receptacle may be monitored by a sensor to help determine when it is desirable to replace the receptacle with the replacement receptacle.

What is claimed is:  
     
         1 . A method of producing thin cast steel strip by continuous casting comprising the steps of: 
 a) assembling a pair of cooled casting rolls having a nip between them;    b) introducing molten steel between the pair of casting rolls through a metal delivery system configured to a casting pool of molten metal supported on casting surfaces of the casting rolls;    c) counter-rotating the casting rolls to form metal shells on the casting surfaces of the casting rolls;    d) forming solidified thin steel strip through the nip between the casting rolls from said formed metal shells;    e) discharging strip into a first scrap receptacle positioned in a scrap receiving position;    f) replacing the first scrap receptacle with a replacement scrap receptacle by the steps comprising: 
 (i) optionally, interrupting the flow of molten steel to the metal delivery system,  
 (ii) moving the first scrap receptacle away from the scrap receiving position,  
 (iii) positioning a replacement scrap receptacle into the scrap receiving position, and  
 (iv) continuing or resuming the flow of molten steel to the metal delivery system to cast steel strip.  
   
     
     
         2 . The method described in  claim 1  comprising the additional step of monitoring the status of the first scrap receptacle or replacement scrap receptacle in the scrap receiving position.  
     
     
         3 . The method described in  claim 2  where a sensor is used to monitor the status of a scrap receptacle in the scrap receiving position.  
     
     
         4 . The method described in  claim 3  where the sensor is an optical device.  
     
     
         5 . The method described in  claim 3  where the sensor is a scale.  
     
     
         6 . The method described in  claim 1  where the step of introducing molten steel between the pair of casting rolls comprises the step of positioning above the casting rolls a molten delivery system configured to introduce the molten steel between the pair of casting rolls, and. 
 the step of replacing the first scrap receptacle with the replacement scrap receptacle comprises the steps of: 
 i) interrupting the flow of molten steel to the metal delivery system;  
 ii) moving the first receptacle away from the scrap receiving position,  
 iii) bringing the replacement scrap receptacle into the scrap receiving position, and  
 iv) resuming the flow of molten steel by the metal delivery system to the casting pool and continuing casting of steel strip.  
 
 
     
     
         7 . The method described in  claim 6  wherein the flow of molten steel to the casting pool is interrupted by draining the casting pool.  
     
     
         8 . The method described in  claim 1  where the step of replacing the first scrap receptacle with the replacement scrap receptacle comprises the steps of: 
 i) continuing the flow of molten steel to the casting pool;  
 ii) moving the first receptacle away from the scrap receiving position,  
 iii) bringing the second scrap receptacle into the scrap receiving position, and  
 iv) continuing casting of steel strip.  
 
     
     
         9 . The method described in  claim 1  where the step of moving the first receptacle away from the scrap receiving position comprises the step of breaking a seal between the first scrap receptacle and a wall enclosure of an enclosure enclosing the pair of casting rolls.  
     
     
         10 . The method described in  claim 6  where not more than about 5 minutes elapses between the steps of interrupting and resuming the flow of molten steel to the metal delivery system.  
     
     
         11 . The method described in  claim 6  where not more than about 240 seconds elapses between the steps of interrupting and resuming the flow of molten steel to the metal delivery system.  
     
     
         12 . The method described in  claim 6  further comprising the step of monitoring the status of the scrap in the first scrap receptacle or replacement scrap receptacle in the scrap receiving position.  
     
     
         13 . The method described in  claim 6  further comprising the step of monitoring the status of the scrap in the first scrap receptacle or replacement scrap receptacle in the scrap receiving position.  
     
     
         14 . A twin roll caster apparatus for casting metal strip comprising: 
 (a) a pair of generally horizontal casting rolls forming a nip between them,    (b) a metal delivery system capable of delivering molten metal between the casting rolls to form a casting pool of molten metal supported on the casting rolls,    (c) roll drivers to counter rotate the casting rolls thereby producing a cast strip delivered downwardly from the nip,    (d) a sealed enclosure to receive the strip delivered from the nip formed with an opening in an enclosure wall, and a first moveable scrap receptacle capable of being positioned in sealing engagement with the enclosure wall around the opening, and    (e) the enclosure being configured to allow replacement of the first moveable scrap receptacle by replacement moveable receptacle during casting operation by breaking the seal of the first scrap receptacle with the enclosure wall and thereafter making the seal by the replacement scrap receptacle with the enclosure wall.    
     
     
         14 . The twin roll caster described in  claim 13  where the pair of casting rolls are disposed within an enclosure configured to form a seal with the first scrap receptacle or alternatively the replacement scrap receptacle when disposed in the scrap receiving position.  
     
     
         15 . The twin roll caster described in  claim 13  further comprising an elevating mechanism configured to move the first scrap receptacle between a raised position and a lowered position.  
     
     
         16 . A twin roll caster apparatus comprising: 
 (a) a pair of generally horizontal casting rolls forming a nip therebetween,    (b) a metal delivery system comprising a delivery vessel and a delivery nozzle through which to deliver molten steel between the casting rolls above the nip to form a casting pool of molten steel supported on the casting rolls,    (c) roll drivers to counter-rotate the casting rolls to produce a cast strip delivered downwardly from the nip, and    (d) a sealed enclosure to receive the strip delivered from the nip having a wall enclosure in sealing engagement with a first moveable scrap receptacle configured to be replaced by a replacement moveable scrap receptacle during casting operations with little or no interruption in the casting of steel strip.    
     
     
         17 . The twin roll caster apparatus described in  claim 16  where the pair of casting rolls are disposed within an enclosure configured to form a seal with the first scrap receptacle or alternatively the replacement scrap receptacle when disposed in the scrap receiving position.  
     
     
         18 . The twin roll caster apparatus described in  claim 16  further comprising an elevating mechanism configured to move the first scrap receptacle between a raised position and a lowered position.