Thin strips or foils of alfesi alloy

Abstract

The invention relates to a thin strip or foil, having a thickness of 6 to 200 ?m, preferably, of 6 to 50 ?m, and composed of an alloy containing (in weight %) Si: 1.0 to 1.5, Fe: 1.0 to 1.5, Cu <0.2, Mn <0.1, other elements <0.05 each up to a total <0.15, the remainder being Al. The annealed thin strip or foil has a tensile strength R m >110 MPa for a thickness >9 ?m and >100 MPa for a thickness of 6 to 9 ?m, and an elastic limit R 0.2 >70 MPa. Preferably, said alloy has a silicon content of 1.1 to 1.3% and an iron content of 1.0 to 1.2%. The aforementioned thin strips or foils may be used especially for the production of multilayer composites, overcaps for bottles or aluminium wrappings.

1 . Thin strip or foil between 6 μm and 200 μm thick, and preferably between 6 μm and 50 μm thick, of an alloy with the following composition (% by weight): 
 Si: 1.0-1.5; Fe: 1.0-1.5; Cu <0.2; Mn <0.1; other elements <0.05 each and <0.15 total, remainder Al, with an ultimate tensile strength R m  in the annealed temper >110 MPa for thicknesses >9 μm and >100 MPa for thicknesses between 6 μm and 9 μm.    
     
     
         2 . Thin strip or foil according to  claim 1 , characterized in that it has an ultimate tensile strength R m  in the annealed temper >115 MPa for thicknesses >9 μm.  
     
     
         3 . Thin strip or foil according  claim 1 , characterized in that it has a yield stress R 0.2  >70 MPa.  
     
     
         4 . Thin strip or foil according to  claim 1 , characterized in that its ultimate elongation A is a function of the thickness, as follows:  
       
         
           
                 
                 
                 
               
                     
                 
                     
                 
                   Thickness (μm) 
                   A (%) greater than 
                   and preferably than 
                 
                     
                 
                     
                 
                 
                 
                 
               
                   6-9 
                   3 
                   4 
                 
                    9-15 
                   5 
                   7 
                 
                   15-25 
                   10 
                   15 
                 
                   25-50 
                   18 
                   25 
                 
                    50-200 
                   20 
                   25 
                 
                     
                 
                     
                 
             
                
                
                
                
               
               
                
               
            
             
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         5 . Thin strip or foil according to  claim 1 , characterized in that the alloy has a composition such that Si/Fe ≧0.95.  
     
     
         6 . Thin strip or foil according to  claim 1 , characterized in that the silicon content of the alloy is between 1.1% and 1.3% and its iron content is between 1.0% and 1.2%.  
     
     
         7 . Manufacturing process for thin strips thinner than 200 μm made of an Al—Fe—Si alloy with composition (% by weight): 
 Si: 1.0-1.5; Fe: 1.0-1.5; Cu <0.2; Mn <0.1; other elements <0.05 each and <0.15 total, remainder Al,    including the preparation of a first strip either by vertical semi-continuous casting of a plate and hot rolling, or by continuous casting possibly followed by hot rolling, cold rolling of this first strip down to the final thickness, possibly with intermediate annealing at a temperature between 250° C. and 350° C., and preferably between 280° C. and 340° C., and final annealing at a temperature between 200° C. and 370° C.    
     
     
         8 . Process according to  claim 7 , characterized in that the alloy has a composition such that Si/Fe ≧0.95.  
     
     
         9 . Process according to  claim 7 , characterized in that the first strip is subjected to an homogenisation at a temperature between 450 and 500° C. before cold rolling.  
     
     
         10 . Process according to  claim 7 , characterized in that the strip is prepared by continuous twin-roll casting.