Method for making can end tab stock

Abstract

End or tab stock and a method for its manufacture in which a low alloy content aluminum alloy is continuously cast to form a hot feedstock, the hot feedstock is rapidly annealed and quenched rapidly to prevent substantial precipitation of alloying elements and rolled. The can end and tab stock of the invention has strength and formability equal to higher alloy content aluminum alloy.

What is claimed is:  
     
         1 . A method for making can end and tab stock comprising the steps of: 
 (a) continuous casting an aluminum alloy to form a feedstock;    (b) hot rolling the feedstock;    (c) annealing the feedstock to effect recrystallization without causing substantial precipitation of alloying elements;    (d) final rolling the feedstock to form a sheet; and    (e) coiling the sheet at a temperature between 250°F. and 550° F.    
     
     
         2 . The method in accordance with    claim 1    wherein the hot rolling temperature is between 500° F. and the solidus temperature of the feedstock.  
     
     
         3 . The method in accordance with    claim 1    wherein the feedstock is annealed at a temperature between 600° F. and 1100° F.  
     
     
         4 . The method in accordance with    claim 1    wherein the sheet is coiled at a temperature between 300°F. and 475° F.  
     
     
         5 . The method in accordance with    claim 1    wherein the sheet is coiled at a temperature between 250° F. and 450° F.  
     
     
         6 . The method in accordance with    claim 1    wherein the sheet is coiled at a temperature between 300° F. and 500° F.  
     
     
         7 . The method as defined in    claim 1    wherein each of the steps is carried out in a continuous in-line sequence.  
     
     
         8 . The method as defined in    claim 1    further comprising the step of forming the sheet into a can end or a tab.  
     
     
         9 . The method as defined in    claim 1    further comprising separately quenching the feedstock after annealing separately from any quench that occurs during rolling.  
     
     
         10 . The method as defined in    claim 1    wherein the continuous cast feedstock has a thickness less than 1.0 inches.  
     
     
         11 . The method as defined in    claim 1    wherein the continuous cast feedstock has a thickness between 0.07 and 0.12 inches.  
     
     
         12 . The method as defined in    claim 1    wherein the sheet has a thickness between 0.0080 and 0.014 inches.  
     
     
         13 . The method as defined in    claim 1    wherein the can end or tab stock contains 0.15 to about 0.5% by weight silicon, from 0.2 to about 0.5% by weight iron, from about 0.1 to about 0.6% by weight copper, about 0.5 to 1.2% by weight manganese, and about 0.5 to 2.0% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         14 . The method as defined in    claim 1    wherein the aluminum alloy is continuously cast by depositing molten aluminum between a pair of continuously moving metal belts.  
     
     
         15 . The method as defined in    claim 1    wherein the feedstock has a width less than 24 inches.  
     
     
         16 . The method as defined in    claim 1    wherein the aluminum alloy contains 0 to about 0.6% by weight silicon, from 0 to about 0.8% by weight iron, 0 to about 0.6% by weight copper, about 0.2 to 1.5% by weight manganese, and about 0.2 to 2% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         17 . The method as defined in    claim 1    wherein the aluminum alloy contains less than 2% magnesium.  
     
     
         18 . The method as defined in    claim 1    wherein the aluminum alloy contains 0.15 to about 0.5% by weight silicon, from 0.2 to about 0.5% by weight iron, from about 0.1 to about 0.6% by weight copper, about 0.5 to 1.2% by weight manganese, and about 0.5 to 2.0% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         19 . A method for making end and tab stock for aluminum containers, comprising: 
 (a) continuous casting an aluminum alloy to form a feedstock;    (b) hot rolling the feedstock at a temperature between 500° F. and 1000°F.;    (c) annealing the feedstock at a temperature between 600°F. and 1100°F.;    (d) quenching the feedstock by contacting the feedstock with a cooling substance;    (e) rolling the feedstock to form a sheet; and    (f) coiling the sheet at a temperature between 300° F. and 475° F.    
     
     
         20 . Can end or tab stock for aluminum alloy containers formed of aluminum alloy containing less than about 2% by weight magnesium produced by continuous casting an aluminum alloy to form a feedstock, hot rolling the feedstock, annealing the feedstock to effect recrystallization without causing substantial precipitation of alloying elements, final rolling the feedstock to form a sheet; and coiling the sheet at a temperature between 250° F. and 550° F.  
     
     
         21 . Can end or tab stock as defined in    claim 20    wherein the aluminum alloy contains more than 0.5% by weight magnesium.  
     
     
         22 . Can end or tab stock as defined in    claim 20    wherein the aluminum alloy contains 0 to about 0.6% by weight silicon, from 0 to about 0.8% by weight iron, 0 to about 0.6% by weight copper, about 0.2 to 1.5% by weight manganese, and about 0.2 to 2% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         23 . Can end or tab stock as defined in    claim 20    wherein the aluminum alloy contains 0.15 to about 0.5% by weight silicon, from 0.2 to about 0.5% by weight iron, from about 0.1 to about 0.6% by weight copper, about 0.5 to 1.2% by weight manganese, and about 0.5 to 2.0% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         24 . Can end or tab stock for aluminum alloy containers as defined in    claim 20    having an ultimate tensile strength of at least 50,000 psi.  
     
     
         25 . Can end or tab stock for aluminum alloy containers as defined in    claim 20    wherein the sheet is coiled at a temperature between 300° F. and 475° F.  
     
     
         26 . Can end or tab stock for aluminum alloy containers as defined in    claim 20    wherein the sheet is coiled at a temperature between 250° F. and 450° F.  
     
     
         27 . Can end or tab stock for aluminum alloy containers as defined in    claim 20    wherein the sheet is coiled at a temperature between 300° F. and 500° F.  
     
     
         28 . A can end or tab for aluminum alloy containers formed of aluminum alloy containing less than about 2% by weight magnesium produced by continuous casting an aluminum alloy to form a feedstock, hot rolling the feedstock, annealing the feedstock to effect recrystallization without causing substantial precipitation of alloying elements, final rolling the feedstock to form a sheet; coiling the sheet at a temperature between 250°F. and 500° F., and forming the sheet into an end or tab.  
     
     
         29 . A can end or tab as defined in    claim 28    wherein the aluminum alloy contains more than 0.5% by weight magnesium.  
     
     
         30 . A can end or tab as defined in    claim 28    wherein the aluminum alloy contains 0 to about 0.6% by weight silicon, from 0 to about 0.8% by weight iron, 0 to about 0.6% by weight copper, about 0.2 to 1.5% by weight manganese, and about 0.2 to 2% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         31 . A can end or tab as defined in    claim 28    wherein the aluminum alloy contains 0.15 to about 0.5% by weight silicon, from 0.2 to about 0.5% by weight iron, from about 0.1 to about 0.6% by weight copper, about 0.5 to 1.2% by weight manganese, and about 0.5 to 2.0% by weight magnesium, with the balance being aluminum with its usual impurities.  
     
     
         32 . A can end or tab for aluminum alloy containers as defined in    claim 28    having an ultimate tensile strength of at least 50,000 psi.  
     
     
         33 . A can end or tab for aluminum alloy containers as defined in    claim 28    wherein the sheet is coiled at a temperature between 300° F. and 475° F.  
     
     
         34 . A can end or tab for aluminum alloy containers as defined in    claim 28    wherein the sheet is coiled at a temperature between 250° F. and 450° F.  
     
     
         35 . A can end or tab for aluminum alloy containers as defined in    claim 28    wherein the sheet is coiled at a temperature between 300° F. and 500° F.  
     
     
         36 . The method in accordance with    claim 19    further comprising forming the sheet into an end or tab.  
     
     
         37 . The method in accordance with    claim 20    further comprising quenching the feedstock prior to final rolling.  
     
     
         38 . The method in accordance with    claim 28    further comprising quenching the feedstock prior to final rolling.