Casting Method and Casting Installation for Aluminium or Aluminium Alloys

Abstract

The invention relates to a casting method for aluminium or aluminium alloys, in which molten aluminium is treated and fed to at least one casting station ( 33, 34 ), in which the molten metal is cast into semi-finished products or similar. A number of casting ladles ( 25 ) are used to treat and feed the molten aluminium to the respective casting station ( 33, 34 ). The ladles are filled with the molten metal and the latter is then transported to at least one additional stage ( 32 ), where it is treated. The molten metal is subsequently delivered in the ladles ( 25 ) to the casting station ( 33, 34 ), where the ladles ( 25 ) are emptied. The invention thus provides an efficient method that can be flexibly adapted to the time periods of the process, said periods altering according to the situation.

1 . Casting method for aluminium or aluminium alloys, in which molten aluminium is treated and fed to at least one casting station ( 33 ,  34 ), in which the molten aluminium is cast into semi-finished products or similar, characterised in that a number of ladles ( 25 ) are used to treat and to feed the molten aluminium to the respective casting station ( 33 ,  34 ), the melt being poured into said ladles, transported to a further stage ( 32 ) and treated there, and is then delivered to the casting station ( 33 ,  34 ), in which the ladles ( 25 ) are emptied. 
   
   
       2 . Casting method according to  claim 1 , characterised in that in a further stage ( 30 ) the emptied ladles ( 25 ) are cleaned and prepared for re-use, in particular are pre-heated. 
   
   
       3 . Casting method according to  claim 1 , characterised in that in the first stage ( 21 ) the melt is poured from one or alternatively from several furnaces ( 22 ,  23 ,  24 ) into the ladles ( 25 ), whereby if there are several furnaces ( 22 ,  23 ,  24 ) molten aluminium of varying quality from the individual furnaces ( 22 ,  23 ,  24 ) can be poured into the ladles ( 25 ). 
   
   
       4 . Casting method according to  claim 3 , characterised in that induction furnaces are used in the first stage ( 21 ). 
   
   
       5 . Casting methods according to  claim 1 , characterised in that after filling the respective pan ( 25 ), the dross is skimmed off the surface of the melting bath (dedrossing) to which end the pan is brought into a tilted position. 
   
   
       6 . Casting method according to  claim 1 , characterised in that the second stage ( 32 ) includes the addition of alloying additions to the melt, their purification and homogenisation and also if necessary any temperature regulation. 
   
   
       7 . Casting method according to  claim 6 , characterised in that in the second treatment stage ( 32 ), the ladles ( 25 ) can be placed underneath an immersible rotary impeller to blow in argon or nitrogen for combined removal of hydrogen, homogenisation and if necessary, thermal regulation, whereby additional small amounts of chlorine can be mixed into the purge gas to remove alkali trace contaminants. 
   
   
       8 . Casting method according to  claim 2 , characterised in that at least part of the alloy additions has been placed in the emptied and cleaned ladles ( 25 ) before the molten aluminium is poured in. 
   
   
       9 . Casting methods according to  claim 1 , characterised in that the ladles ( 25 ) run through the individual stations or stages on rails or by means of overhead hoists, whereby multiple routes lead to preferably several casting stations ( 33 ,  34 ), and to additional storage stations (S) to store ladles ( 25 ) filled with molten aluminium and/or empty ones until use. 
   
   
       10 . Casting method according to  claim 1 , characterised in that the emptying of the ladles ( 25 ) occurs at the respective casting station ( 33 ,  34 ) through the base of the ladles by controlled opening of a sliding closure, whereby the outflowing molten aluminium is guided into a collector spout preferably encased by an inert gas. 
   
   
       11 . Casting method according to  claim 6 , characterised in that the filling of the ladles ( 25 ) with molten aluminium, if necessary with mixed material from various furnaces ( 22 ,  23 ,  24 ), the addition of the alloy additions, homogenisation, thermal regulation and chronological sequence of treatment and feeding of the molten aluminium to the selected casting station ( 33 ,  34 ), is computer-controlled. 
   
   
       12 . Casting method according to  claim 1 , characterised in that the respective casting station ( 33 ,  34 ) operates continuously or semi-continuously and is equipped with a filter system. 
   
   
       13 . Casting machine to carry out the process according to  claim 1 , with at least one casting station ( 33 ,  34 ) and with means of treating and feeding molten aluminium to the casting station ( 33 ,  34 ), characterised in that the means of treating and feeding molten aluminium comprise a number of ladles ( 25 ) fillable in a first filling station ( 21 ) with the molten aluminium, which are transportable to a second treatment station ( 32 ) and from there to the respective casting station ( 33 ,  34 ), whereby multiple routes for the transport are provided, and the ladles ( 25 ) are each fitted with a sliding closure or similar, by the opening of which they can be emptied. 
   
   
       14 . Casting machine according to  claim 13 , characterised in that a further purification and preparation station ( 30 ) is provided for the emptied ladles ( 25 ), from which the ladles ( 25 ) are transportable to the filling station ( 21 ). 
   
   
       15 . Casting machine according to  claim 13 , characterised in that additional storage stations (S) are provided for storage of ladles ( 25 ) filled with molten aluminium and/or emptied ladles ( 25 ) until use. 
   
   
       16 . Casting machine according to  claim 13 , characterised in that the filling station ( 21 ) is provided with a number of furnaces ( 22 ,  23 ,  24 ) which can be supplied with basic material, preferably induction furnaces, whereby the individual furnaces ( 22 ,  23 ,  24 ) can if necessary be supplied with aluminium material of varying quality. 
   
   
       17 . Casting machine according to  claim 13 , characterised in that the ladles ( 25 ) can be covered by a cover in which a burner can be installed to maintain or to increase the temperature of the molten aluminium. 
   
   
       18 . Casting machine according to  claim 13 , characterised in that the ladles ( 25 ) are equipped with a porous plug for injection of an inert gas. 
   
   
       19 . Casting machine according to  claim 13 , characterised in that rails or hoists are provided for the transport of the ladles ( 25 ) from one station to the next and to the storage stations (S).