Composition and method of forming aluminum alloy foil

Abstract

The present invention provides an aluminum alloy foil for fins used in heat exchangers. The aluminum alloy composition consists essentially of about 0.25% to about 0.6% by weight of Si; about 0.15% to about 0.50% by weight of Fe; about 0.20% to about 0.70% by weight of Mn; less than about 0.05% Cu; and less than about 0.05% Mg, with the balance aluminum including unavoidable impurities. The alloy composition may also contain less than 0.10% Zn or 0.50-2.00% Zn. The invention also provides a method for making an aluminum alloy wherein during cold rolling interanneal is carried out at a gauge such that the cold work after internanneal is between about 30-70%.

What is claimed is:  
     
         1 . An molten aluminum-based alloy consisting essentially of about 0.25% to about 0.60% by weight of Si; about 0.15% to about 0.50% by weight of Fe; about 0.20% to about 0.70% by weight of Mn; less than about 0.05% Cu; and less than about 0.05% Mg, with the balance aluminum including unavoidable impurities.  
     
     
         2 . The alloy of  claim 1 , wherein the alloy contains 0.10% by weight of Zn.  
     
     
         3 . The alloy of  claim 1 , wherein the alloy contains 0.50-2.00% by weight of Zn.  
     
     
         4 . The alloy of  claim 1 , wherein the alloy contains about 0.3-0.5% by weight of silicon.  
     
     
         5 . The alloy of  claim 1 , wherein the alloy contains about 0.15-0.35% by weight of iron.  
     
     
         6 . The alloy of  claim 1 , wherein the alloy contains about 0.30-0.60% by weight of manganese.  
     
     
         7 . The alloy of  claim 1 , wherein the alloy contains about 0.40-0.80% by weight of manganese and iron.  
     
     
         8 . The alloy of  claim 1  in the form of a cold rolled sheet, wherein during cold rolling interanneal is carried out at a gauge such that the cold work after interanneal is between 30-70%.  
     
     
         9 . An aluminum foil made in accordance with the process of  claim 12 .  
     
     
         10 . A heat exchanger having fins comprising an alloy having a composition in accordance with  claim 1 .  
     
     
         11 . A fin for a heat exchanger comprising an alloy having a composition in accordance with  claim 1 .  
     
     
         12 . A method for making an aluminum alloy foil, comprising: 
 providing a molten aluminum-based alloy consisting essentially of about 0.25% to about 0.60% by weight fo Si; about 0.20% to about 0.70% by weight of Fe; about 0.20% to about 0.70% by weight of Mn; less than about 0.05%Cu; and less than about 0.05% Mg, with the balance aluminum including unavoidable impurities;    continuously casting an aluminum alloy strip from said molten aluminum alloy; and cold rolling the continuously cast aluminum alloy strip to a final gauge of between about 0.002-0.008 inches.    
     
     
         13 . The method of  claim 12 , wherein during cold rolling interanneal is carried out at a gauge such that the cold work after interanneal is between 30-70%.  
     
     
         14 . The method of  claim 12 , wherein the alloy contains 0.10% by weight of Zn.  
     
     
         15 . The method of  claim 12 , wherein the alloy contains 0.50-2.00% by weight of Zn.  
     
     
         16 . The method of  claim 12 , wherein the alloy contains about 0.3-0.5% by weight of silicon.  
     
     
         17 . The method of  claim 12 , wherein the alloy contains about 0.15-0.35% by weight of iron.  
     
     
         18 . The method of  claim 12 , wherein the alloy contains about 0.30-0.60% by weight of manganese.  
     
     
         19 . The method of  claim 12 , wherein the alloy contains about 0.40-0.80% by weight of manganese plus iron.  
     
     
         20 . The method of  claim 12 , wherein during cold rolling interanneal is carried out at a gauge such that the cold work after interanneal is between about 30-70%.  
     
     
         21 . An aluminum foil made in accordance with the process of  claim 13 .  
     
     
         22 . A heat exchanger having fins comprising an alloy made in accordance with the process of  claim 13 .  
     
     
         23 . A fin for a heat exchanger comprising an alloy made in accordance with the process of  claim 13.