Method for manufacturing very thin aluminum-iron alloy strips

Abstract

The object of the invention is a method for manufacturing aluminum alloy strips with a thickness less than or equal to 12 μm, including: elaboration of an alloy with composition (weight %): Si:0.15-0.40 Fe: 1.10-1.70 Mg<0.02 Mn:0.30-0.50 other elements<0.05 each and total<0.15, remainder is aluminum, continuous casting between rolls of a strip of this alloy with a thickness between 2 and 10 mm, homogenization of this strip at a temperature between 450 and 620° C. with a duration between 8 and 40 hrs, cold-rolling of this strip intermediate annealing of this cold-rolled strip to a temperature between 200 and 400° C., and with a duration between 8 and 15 hrs, cold-rolling of the annealed strip up to the final thickness less than or equal to 12 μm, final annealing of the strip at a temperature between 200 and 300° C., with a duration of at least 50 hrs. The method is notably applied to the manufacturing of strips for aseptic food packages of the brick type.

1 . Method for manufacturing aluminum alloy strips with a thickness less than or equal to 12 μm, including: 
 elaboration of an alloy with composition (% by weight):  
 Si: 0.15-0.40 Fe:1.10-170 mg<0.02 Mn:0.30-0.50  
 other elements<0.05 each and total<0.15, remainder is aluminum,  
 continuous casting between rolls of a strip of this alloy with a thickness between 2 and 10 mm,  
 homogenization of this strip at a temperature between 450 and 620° C., for a duration between 8 and 40 hrs,  
 cold-rolling of this strip,  
 intermediate annealing of the cold-rolled strip at a temperature between 200 and 400° C., and with a duration between 8 and 15 hrs,  
 cold-rolling of the annealed strip to the final thickness less than or equal to 12 μm,  
 final annealing of the strip at a temperature between 200 and 300° C., with a duration of at least 50 hrs.  
 
     
     
         2 . The method according to  claim 1 , characterized in that the thickness of the strip is less than 9 μm.  
     
     
         3 . The method according to any of claims  1  or  2 , characterized in that the iron content of the alloy is less than 1.40%.  
     
     
         4 . The method according to any of  claims 1  to  3 , characterized in that the intermediate annealing is unique, i.e. there are no other ones between both cold-rolling steps.  
     
     
         5 . An aluminum alloy strip with a thickness less than or equal to 12 μm, manufactured by a method according to any of  claims 1  to  4 , characterized in that it has an ultimate strength R m >100 MPa, a yield strength R 0.2 >80 MPa, an ultimate elongation A>3% and a porosity<10 holes/dm 2  according to the EN 546-4 standard.  
     
     
         6 . A use of the strips according to  claim 5  for producing aseptic food packages of the brick type.