Aluminium base alloy of scrap metal and casting alloy produced from this

Abstract

An aluminium base alloy for production of casting alloys with magnesium as the most essential alloy element contains at least 50% scrap metal on primary aluminium base and as the remainder primary aluminium and/or scrap metal on secondary aluminium base of known composition. For production of the aluminium base alloy mainly foodstuff and animal feed packings are used, separated with a pyrolysis process and then the aluminium contained in the packing recycled by melting. The casting alloys produced from the aluminium base alloy are suitable in particular for production of heat-resistant and/or corrosion-resistant parts in the engine area, in particular for production of engine blocks, cylinder heads and oil sumps, by means of sand casting, chilled casting, diecasting, thixocasting or thixoforging.

1 . Aluminium base alloy for production of casting alloys with magnesium as the most essential alloy element, characterised in that 
 it contains at least 50% scrap metal on a primary aluminium base and as the residue primary aluminium and/or scrap metal on a secondary aluminium base of known composition.    
     
     
         2 . Aluminium base alloy according to  claim 1 , characterised in that it consists at least 80%, preferably 100%, of scrap metal on a primary aluminium base.  
     
     
         3 . Aluminium base alloy according to  claim 1  or  2 , characterised in that the scrap metal on a primary aluminium base is mainly recycling metal obtained from foodstuff or animal feed packing.  
     
     
         4 . Process for production of an aluminium base alloy according to any of  claims 1  to  3 , characterised in that materials on a primary aluminium base contaminated with organic compounds are prepared separately according to their thermal value and their aluminium content, combined in measured quantities to achieve a nominal value, the organic compounds carbonised by pyrolysis with formation of pyrolysis gas and pyrolysis coke, the pyrolysis coke separated off, the materials pretreated in this way are where applicable bright annealed, and where applicable are sorted to separate out foil constituents, and then melted.  
     
     
         5 . Process according to  claim 4 , characterised in that aluminium compound substances are reduced to a unit size and the iron parts separated out after pyrolysis.  
     
     
         6 . Process according to  claim 4  or  5 , characterised in that the materials which are prepared separately are combined to achieve a nominal value by way of a computer-controlled metering system, where as applicable in addition to the thermal value and aluminium content of the materials, further parameters of the materials treated can be taken into account, in particular their moisture, apparent density and grain size.  
     
     
         7 . Casting alloy made from an aluminium base alloy according to any of  claims 1  to  3 , characterised in that it also contains 3.0 to 5.0 w. % magnesium and 1.5 to 3.0 w. % silicon.  
     
     
         8 . Casting alloy according to  claim 7 , characterised in that it also contains 0.5 to 1.2 w. % manganese and/or 0.5 to 1.2 w. % copper.  
     
     
         9 . Casting alloy according to  claim 7  or  8 , characterised in that it also contains max 0.2 w. % titanium.  
     
     
         10 . Casting alloy according to any of  claims 7  to  9 , characterised in that it also contains max 0.4 w. % cobalt, max 0.4 w. % cerium and max 1.2 w. % zirconium.  
     
     
         11 . Process for production of a casting alloy according to any of  claims 7  to  10 , characterised in that to a melt of the aluminium base alloy, including where applicable added further alloy elements, are added 0.02 to 0.15 w. % vanadium, preferably 0.02 to 0.08 w. % vanadium, in particular 0.02 to 0.05 w. % vanadium and less than 60 ppm beryllium.  
     
     
         12 . Use of a casting alloy according to any of  claims 7  to  10  produced from an aluminium base alloy according to any of  claims 1  to  3  to produce heat-resistant and/or corrosion-resistant parts in the engine area, in particular for production of engine blocks, cylinder heads and oil sumps, by means of sand casting, chilled casting, diecasting, thixocasting and thixoforging.