Strip casting apparatus for rapid set and change of casting rolls

Abstract

An apparatus and method for continuously casting thin steel strip include a pair of counter-rotatable casting rolls mounted in a roll cassette capable of being transferred from a set up station to a casting position through a transfer station, where at the set up station the casting rolls mounted in the roll cassette are capable of being prepared for casting, at the transfer station casting rolls are capable of being exchanged, and in the casting position the casting rolls are operational, and a guide positioned capable of moving the casting rolls mounted in the roll cassette between the set up station and the casting position through the transfer station. The guide may move the casting rolls mounted in the roll cassette from the set up station to the casting position through the transfer station at substantially the same elevation. A scrap receptacle positioned beneath the casting position movable in either direction to a discharge stations. Further, a movable tundish capable of being transferred from a heating station to the casting position.

1 . An apparatus for continuously casting thin steel strip comprising:
 (a) a pair of counter-rotatable casting rolls having casting surfaces laterally positioned to form a nip there between through which thin cast strip can be cast, and on which a casting pool of molten metal can be formed supported on the casting surfaces above the nip;   (b) the casting rolls mounted in a roll cassette capable of being transferred from a set up station to a casting position through a transfer station, where at the set up station the casting rolls mounted in the roll cassette are capable of being prepared for casting, at the transfer station the casting rolls mounted in a roll cassette are capable of being exchanged, and in the casting position the casting rolls mounted in a roll cassette are operational for casting; and   (c) casting roll guides adapted to enable movement of the casting rolls mounted in a roll cassette between the set up station and the transfer station and between the transfer station and the casting position.   
   
   
       2 . The apparatus for continuously casting thin steel strip as claimed in  claim 1 ,
 the casting roll guides comprising rails on which the casting rolls mounted in the roll cassette are capable of being moved between the set up station and the casting position through the transfer station, first rails extending between the set up station and the transfer station, second rails extending between the transfer station and the casting position, and both first and second rails capable of being aligned with rails on a turntable of the transfer station such that the turntable may be turned to exchange casting rolls mounted in roll cassettes between the first rails and the second rails.   
   
   
       3 . The apparatus for continuously casting thin steel strip as claimed in  claim 2  where
 the first and second rails are adapted to enable movement of the casting rolls mounted in the roll cassette from the set up station to the casting position through the transfer station at substantially the same elevation.   
   
   
       4 . The apparatus for continuously casting thin steel strip as claimed in  claim 2  where
 the first and second rails are adapted to enable movement of the casting rolls mounted in a roll cassette between the set up station and the transfer station at a different elevation than moving the casting rolls from the transfer stations to the casting position.   
   
   
       5 . The apparatus for continuously casting thin steel strip as claimed in  claim 4  where
 the casting rolls, optionally with the roll cassette, are moved at the casting position to an operating position for casting.   
   
   
       6 . The apparatus for continuously casting thin steel strip as claimed in  claim 1  where
 the casting roll guides are adapted to enable movement of the casting rolls mounted in the roll cassette from the set up station to the casting position through the transfer station at substantially the same elevation.   
   
   
       7 . The apparatus for continuously casting thin steel strip as claimed in  claim 6  where
 the casting roll guides are adapted to enable movement of the casting rolls mounted in the roll cassette between the set up station and the transfer station at a different elevation than moving the casting rolls from the transfer stations to the casting position.   
   
   
       8 . The apparatus for continuously casting thin steel strip as claimed in  claim 7  where
 the casting rolls, optionally with the roll cassette, are moved at the casting position to an operating position for casting.   
   
   
       9 . The apparatus for continuously casting thin steel strip as claimed in  claim 1  further comprising:
 an enclosure capable of supporting a protective atmosphere immediately beneath the casting rolls in the casting position; and   an upper cover capable of moving between a closed position covering the upper portion of the enclosure and a retracted position enabling cast strip to be cast downwardly from the nip into the enclosure.   
   
   
       10 . The apparatus for continuously casting thin steel strip as claimed in  claim 9  further comprising:
 guides positioned to enable movement of the upper cover between the closed position and the retracted position; and   a plurality of actuators selected from the group consisting of servo-mechanisms, hydraulic mechanisms, pneumatic mechanisms, and rotating actuators and capable of moving the upper cover along the guides between the closed position and the retracted position.   
   
   
       11 . The apparatus for continuously casting thin steel strip as claimed in  claim 9  further comprising:
 an upper collar portion movable between an extended position supporting the protective atmosphere immediately beneath the casting rolls in the casting position and an open position enabling the upper cover to move into the closed position; and   a plurality of actuators selected from the group consisting of servo-mechanisms, hydraulic mechanisms, pneumatic mechanisms, and rotating actuators and capable of moving the upper collar between the extended position and the open position.   
   
   
       12 . The apparatus for continuously casting thin steel strip as claimed in  claim 1 , the roll cassette comprising in addition:
 a housing portion positioned beneath the casting rolls capable of supporting a protective atmosphere immediately beneath the casting rolls in the casting position; and   a knife seal positioned adjacent each casting roll adjoining the housing portion and forming a partial closure between the housing portion and the rotating casting rolls.   
   
   
       13 . The apparatus for continuously casting thin steel strip as claimed in  claim 1 , comprising in addition:
 (d) at least one scrap receptacle capable of being positioned beneath the casting rolls in the casting position and movable in either direction away from the casting position by a scrap receptacle guide to discharge stations, each scrap receptacle capable of attaching with an enclosure and supporting a protective atmosphere immediately beneath the casting rolls in the casting position.   
   
   
       14 . The apparatus for continuously casting thin steel strip as claimed in  claim 13 ,
 the scrap receptacle guide comprising rails extending in opposite directions from the casting position, the rails capable of supporting at least two scrap receptacles movable along the rails from the casting position to the discharge stations.   
   
   
       15 . The apparatus for continuously casting thin steel strip as claimed in  claim 13  further comprising:
 (d) a rim portion capable of sealingly engaging an upper portion of a scrap receptacle positioned beneath the casting position.   
   
   
       16 . The apparatus for continuously casting thin steel strip as claimed in  claim 15  comprising in addition:
 a lower plate operatively positioned within the enclosure capable of closing a lower portion of the enclosure when the rim portion is disengaged from the scrap receptacle.   
   
   
       17 . The apparatus for continuously casting thin steel strip as claimed in  claim 16  where
 the lower plate comprising at least one portion pivotably, mounted to move between a closed position and a retracted position; and   a plurality of actuators selected from the group consisting of servo-mechanisms, hydraulic mechanisms, pneumatic mechanisms, and rotating actuators and capable of moving the lower plate between the closed position and a retracted position.   
   
   
       18 . The apparatus for continuously casting thin steel strip as claimed in  claim 1  further comprising:
 (d) a movable tundish capable of being transferred from a heating station to the casting position and capable of receiving molten metal and transferring the molten metal to the casting pool through a distributor and a core nozzle when in the casting position, and   (e) a tundish guide adapted to enable movement of the movable tundish from the heating station where the movable tundish is capable of being heated to an operative temperature to the casting position.   
   
   
       19 . The apparatus for continuously casting thin steel strip as claimed in  claim 18 , further comprising:
 a loading device capable of moving the distributor from a stand-by position to the casting position, at least a portion of the loading device being overhead from the elevation of the distributor positioned in the casting position.   
   
   
       20 . The apparatus for continuously casting thin steel strip as claimed in  claim 18 ,
 further comprising a loading device having at least one loading arm movable with the movable tundish on the tundish guide and capable of moving the distributor from the stand-by position and placing the distributor over the casting rolls in the casting position.   
   
   
       21 . The apparatus for continuously casting thin steel strip as claimed in  claim 18 ,
 the tundish guide comprising rails extending between the heating station and the casting position.   
   
   
       22 . The apparatus for continuously casting thin steel strip as claimed in  claim 18 , where:
 the movable tundish is capable of being movable in either direction away from the casting position via the tundish guide.   
   
   
       23 . The apparatus for continuously casting thin steel strip as claimed in  claim 13  further comprising:
 (e) a movable tundish capable of being transferred from a heating station to the casting position and capable of receiving molten metal and transferring the molten metal to the casting pool through a distributor and a core nozzle when in the casting position, and   (f) a tundish guide adapted to enable movement of the movable tundish from the heating station where the movable tundish is capable of being heated to an operative temperature to the casting position.   
   
   
       24 . The apparatus for continuously casting thin steel strip as claimed in  claim 23 , further comprising:
 a loading device adapted to enable movement of the distributor from a stand-by position to the casting position, at least a portion of the loading device being overhead from the elevation of the distributor positioned in the casting position.   
   
   
       25 . The apparatus for continuously casting thin steel strip as claimed in  claim 23 ,
 a loading device having at least one loading arm movable with the movable tundish on the tundish guide and capable of moving the distributor from the stand-by position and placing the distributor over the casting rolls in the casting position.   
   
   
       26 . The apparatus for continuously casting thin steel strip as claimed in  claim 23 ,
 the tundish guide comprising rails extending between the heating station and the casting position.   
   
   
       27 . The apparatus for continuously casting thin steel strip as claimed in  claim 23  where
 the movable tundish is capable of being movable in either direction away from the casting position via the tundish guide.   
   
   
       28 . An apparatus for continuously casting thin steel strip having a pair of counter-rotatable casting rolls mounted in a roll cassette and having casting surfaces laterally positioned to form a nip there between through which thin cast strip can be cast, and on which a casting pool of molten metal can be supported on the casting surfaces above the nip, the improvement providing for rapid exchange of casting rolls comprising:
 an enclosure capable of supporting a protective atmosphere immediately beneath the casting rolls in a casting position; and   an upper cover capable of moving between a closed position covering the upper portion of the enclosure and a retracted position enabling cast strip to be cast downwardly from the nip into the enclosure.   
   
   
       29 . The enclosure for an apparatus for continuously casting thin steel strip as claimed in  claim 28 , further comprising:
 an upper collar portion movable between an extended position supporting the protective atmosphere immediately beneath the casting rolls in the casting position and an open position enabling the upper cover to move into the closed position; and   a plurality of actuators selected from the group consisting of servo-mechanisms, hydraulic mechanisms, pneumatic mechanisms, and rotating actuators and capable of moving the upper collar between the extended position and the open position.   
   
   
       30 . The apparatus for continuously casting thin steel strip as claimed in  claim 28 , the roll cassette comprising in addition:
 a housing portion positioned beneath the casting rolls capable of supporting a protective atmosphere immediately beneath the casting rolls in the casting position; and   a knife seal positioned adjacent each casting roll and adjoining the housing portion and forming a partial closure between the housing portion and the rotating casting rolls.   
   
   
       31 . The enclosure for an apparatus for continuously casting thin steel strip as claimed in  claim 28 , further comprising:
 a rim portion capable of sealingly engaging an upper portion of a scrap receptacle positioned beneath the casting position.   
   
   
       32 . The enclosure for an apparatus for continuously casting thin steel strip as claimed in  claim 31 , further comprising:
 a lower plate operatively positioned within the enclosure capable of closing a lower portion of the enclosure when the rim portion is disengaged from the scrap receptacle.   
   
   
       33 . The apparatus for continuously casting thin steel strip as claimed in  claim 32  where
 the lower plate is capable of being pivotably moved into a closed position; and   a plurality of actuators selected from the group consisting of servo-mechanisms, hydraulic mechanisms, pneumatic mechanisms, and rotating actuators and capable of moving the lower plate between the closed position and a retracted position.   
   
   
       34 . A method of continuously casting thin steel strip comprising steps of:
 (a) assembling a first pair of counter-rotatable casting rolls having casting surfaces laterally positioned to form a nip there between through which thin cast strip can be cast, and on which a casting pool of molten metal may be formed supported on the casting surfaces above the nip,   (b) preparing the first casting rolls mounted in a roll cassette for casting at a set up station;   (c) moving the first casting rolls mounted in a roll cassette to a transfer station;   (d) moving the first casting rolls mounted in a roll cassette from the transfer station to casting position where the pair of counter-rotatable casting rolls is positioned for casting thin strip.   
   
   
       35 . The method of continuously casting thin steel strip as claimed in  claim 34  further comprising:
 (e) exchanging at the transfer station the first casting rolls mounted in a roll cassette with second casting rolls mounted in a second roll cassette, and   (f) moving the second casting rolls mounted in a second roll cassette from the transfer station to the set up station where the second casting rolls can be changed.   
   
   
       36 . The method of continuously casting thin steel strip as claimed in  claim 35  comprising in addition
 moving the first and second casting rolls mounted in roll cassettes between the set up station and the casting position on rails, with first rails extending between the set up station and the transfer station, second rails extending between the transfer station and the casting position, and the first and second rails capable of being aligned with rails on a turntable at the transfer station such that the turntable may be turned to exchange casting rolls mounted in a roll cassette between the first rails and the second rails.   
   
   
       37 . The method of continuously casting thin steel strip as claimed in  claim 36  comprising in addition
 moving the first and second casting rolls mounted in roll cassettes between the set up station and the transfer station at a different elevation than moving the first or second casting rolls mounted in roll cassettes from the transfer stations to the casting position.   
   
   
       38 . The method of continuously casting thin steel strip as claimed in  claim 35  comprising in addition
 moving the first and second casting rolls mounted in roll cassettes between the set up station and the casting position through the transfer station at substantially the same elevation.   
   
   
       39 . The method of continuously casting thin steel strip as claimed in  claim 36  comprising in addition:
 moving the casting rolls, optionally with the roll cassette, at the casting position to place the casting rolls in an operating position for casting.   
   
   
       40 . The method of continuously casting thin steel strip as claimed in  claim 34  comprising in addition
 moving the first casting rolls mounted in a roll cassette between the set up station and the casting position through the transfer station at substantially the same elevation.   
   
   
       41 . The method of continuously casting thin steel strip as claimed in  claim 40  comprising in addition:
 moving the casting rolls, optionally with the roll cassette, at the casting position to place the casting rolls in an operating position for casting.   
   
   
       42 . The method of continuously casting thin steel strip as claimed in  claim 34  further comprising the steps of:
 providing an enclosure capable of supporting a protective atmosphere immediately beneath the casting rolls in the casting position having an upper cover capable of moving between a closed position covering the upper portion of the enclosure and a retracted position;   moving the upper cover to the retracted position enabling cast strip to be cast downwardly from the nip into the enclosure.   
   
   
       43 . The method of continuously casting thin steel strip as claimed in  claim 42  where
 the enclosure further comprises an upper collar portion movable between an extended position supporting the protective atmosphere immediately beneath the casting rolls in the casting position and an open position enabling the upper cover to move into the closed position, comprising in addition the step of:   extending the upper collar into sealing engagement with the roll cassette and supporting the protective atmosphere immediately beneath the casting rolls in the casting position.   
   
   
       44 . The method of continuously casting thin steel strip as claimed in  claim 34 , comprising in addition:
 assembling at least one scrap receptacle capable of being positioned beneath the casting rolls in the casting position and movable in either direction away from the casting position by scrap receptacle guides to discharge stations, each scrap receptacle capable of attaching with an enclosure capable of supporting a protective atmosphere immediately beneath the casting rolls in the casting position.   
   
   
       45 . The method of continuously casting thin steel strip as claimed in  claim 44  further comprising:
 positioning rails to form the scrap receptacle guides in opposite directions from the casting position, the rails capable of supporting at least two scrap receptacles movable along the rails from the casting position to the discharge stations away from the casting position.   
   
   
       46 . The method of continuously casting thin steel strip of  claim 45  further comprising:
 providing a second scrap receptacle movable along the rails;   closing a lower portion of the enclosure further capable of supporting the protective atmosphere immediately beneath the casting rolls in the casting position;   detaching the first scrap receptacle from the enclosure without stopping casting and moving the first scrap receptacle along the rails in a direction away from the second scrap receptacle to a discharge station;   moving the second scrap receptacle into the casting position and attaching the second scrap receptacle to the enclosure; and   opening the lower portion of the enclosure.   
   
   
       47 . The method of continuously casting thin steel strip of  claim 44  further comprising:
 sealing an upper portion of a scrap receptacle in sealing engagement with the enclosure supporting the protective atmosphere beneath the casting position.   
   
   
       48 . The method of continuously casting thin steel strip of  claim 44  further comprising:
 closing a lower portion of the enclosure when the scrap receptacle is disengaged from the enclosure to enable casting to continue during change of the scrap receptacle, if desired.   
   
   
       49 . The method of continuously casting thin steel strip as claimed in  claim 44  further comprising:
 (f) moving a movable tundish, which is capable of receiving molten metal and transferring the molten metal to the casting pool through a distributor and a core nozzle, from a heating station to the casting position by a tundish guide elevated above the movement of the first casting rolls mounted in a roll cassette from the heating station to the casting position.   
   
   
       50 . The method of continuously casting steel strip as claimed in  claim 49  where
 the tundish guide comprises rails extending between the heating station and the casting position.   
   
   
       51 . The method of continuously casting steel strip as claimed in  claim 49 , further comprising:
 providing a loading device with the movable tundish capable of lifting the distributor from a stand-by position and placing the distributor over the casting rolls in the casting position, the loading device being elevated above the movement of the first casting roll mounted in a roll cassette;   advancing the movable tundish from the heating station to the casting position; and   lifting the distributor from the stand-by position and placing the distributor over the casting rolls in the casting position.   
   
   
       52 . The method of continuously casting steel strip as claimed in  claim 49 , further comprising:
 providing two loading arms with the movable tundish capable of cooperatively lifting the distributor from a stand-by position and placing the distributor over the casting rolls in the casting position, the loading arms being elevated above the movement of the first casting roll mounted in a roll cassette;   advancing the movable tundish from the heating station to the casting position; and   lifting the distributor from the stand-by position below the movable tundish and placing the distributor over the casting rolls in the casting position.   
   
   
       53 . A method of continuously casting steel strip comprising steps of:
 (a) providing rails positioned beneath a casting position and extending in opposite directions there from to discharge stations;   (b) supporting first and second scrap receptacles movable along the rails;   (c) engaging a seal between the first scrap receptacle and an enclosure enabling support of a protective atmosphere beneath a pair of casting rolls;   (d) disengaging the seal between the first scrap receptacle and the enclosure and moving the first scrap receptacle along the rails in a direction away from the second scrap receptacle to a discharge station; and   (e) moving the second scrap receptacle into the casting position and sealingly engaging the second scrap receptacle and the enclosure.   
   
   
       54 . The method of continuously casting steel strip as claimed in  claim 53  further comprising:
 filling the second scrap receptacle with a desired gas before moving the second scrap receptacle into the casting position.   
   
   
       55 . The method of continuously casting steel strip as claimed in  claim 53  further comprising:
 (f) preparing a first pair of counter-rotatable casting rolls mounted in a roll cassette for casting at a set up station;   (g) moving the first casting rolls mounted in a roll cassette from the set up station to a transfer station;   (h) exchanging at the transfer station the first casting rolls mounted in a roll cassette with second casting rolls mounted in a second roll cassette;   (i) moving the first casting rolls mounted in the roll cassette from the transfer station to the casting position where the first pair of counter-rotatable casting rolls are positioned for casting thin strip; and   (j) moving the second casting rolls mounted in the second roll cassette from the transfer station to the set up station where the second casting rolls can be changed.   
   
   
       56 . The method of continuously casting steel strip as claimed in  claim 55  further comprising:
 (k) moving a movable tundish, which is capable of receiving molten metal and transferring the molten metal to a casting pool through a distributor and a core nozzle, from a heating station to the casting position by a tundish guide elevated above the movement of the first and second casting rolls mounted in roll cassettes from the transfer station to the casting position.   
   
   
       57 . The method of continuously casting steel strip as claimed in  claim 56  where
 the tundish guide comprises rails extending between the heating station and the casting position.   
   
   
       58 . The method of continuously casting steel strip as claimed in  claim 56 , further comprising:
 (l) providing a loading device with the movable tundish capable of lifting the distributor from a stand-by position and placing the distributor over the casting rolls in the casting position, the loading device elevated above the movement of the first and second casting rolls,   (m) advancing the movable tundish from the heating station to the casting position; and   (n) moving the distributor from the stand-by position and placing the distributor over the casting rolls in the casting position.   
   
   
       59 . The method of continuously casting steel strip as claimed in  claim 56 , further comprising:
 (l) providing two loading arms with the movable tundish capable of cooperatively moving the distributor from a stand-by position and placing the distributor over the casting rolls in the casting position, the loading arms elevated above the movement of the first and second casting rolls mounted in roll cassettes,   (m) advancing the movable tundish from the heating station to the casting position; and   (n) moving the distributor from the stand-by position below the movable tundish and placing the distributor over the casting rolls in the casting position.   
   
   
       60 . The method of continuously casting steel strip as claimed in  claim 54  further comprising:
 (f) moving a movable tundish, which is capable of receiving molten metal and transferring the molten metal to a casting pool through a distributor and a core nozzle, from a heating station to the casting position by a tundish guide elevated above casting rolls in the casting position.   
   
   
       61 . The method of continuously casting steel strip as claimed in  claim 59  where
 the tundish guide comprises rails extending to heating stations in either direction away from the casting position.   
   
   
       62 . The method of continuously casting steel strip as claimed in  claim 61  further comprising:
 (o) preparing a second movable tundish, which is capable of receiving molten metal and transferring the molten metal to the casting pool through a distributor and a core nozzle, at one heating station;   (p) moving the first movable tundish from the casting position along the rails in a direction away from the second movable tundish to another heating station; and   (q) moving the second movable tundish to the casting position along the rails.   
   
   
       63 . A method of continuously casting steel strip using a pair of counter-rotatable casting rolls mounted in a roll cassette having casting surfaces laterally positioned to form a nip there between through which thin cast strip can be cast, and on which a casting pool of molten metal can be formed supported on the casting surfaces above the nip, the improvement providing for rapid exchange of casting rolls comprising the steps of:
 (a) providing an enclosure capable of supporting a protective atmosphere immediately beneath the casting rolls in a casting position having an upper cover capable of moving between a retracted position and a closed position beneath the casting rolls and covering upper portions of the enclosure;   (b) moving the upper cover to the retracted position enabling cast strip to be cast downwardly from the nip into the enclosure; and   (c) moving the upper cover to the closed position retaining the protective atmosphere in the enclosure and enabling the casting rolls to be removed from the casting position.   
   
   
       64 . The method of continuously casting steel strip as claimed in  claim 63 , further comprising the step of:
 engaging an upper collar portion adjacent to the casting rolls to support the protective atmosphere in the enclosure beneath the casting rolls.   
   
   
       65 . The method of continuously casting steel strip as claimed in  claim 63 , comprising in addition the step of:
 engaging a seal between a scrap receptacle and the enclosure to support the protective atmosphere in the enclosure beneath the casting rolls.   
   
   
       66 . The method of continuously casting steel strip as claimed in  claim 65  further comprising:
 closing a lower portion of the enclosure when the seal is disengaged from the scrap receptacle to enable casting to continue during change of the scrap receptacle, if desired.