High-Strength Beverage Can Ends of Aluminum Magnesium Alloy

Abstract

High strength beverage end shells formed in high speed, commercial production of an aluminum alloy having a specific range of constituents, especially magnesium within a specific range.

1 . A method of forming a high strength can end in commercial quantities, comprising the steps of:
 a. providing from a coil a sheet of an aluminum alloy having between 3.0% and 4.5% magnesium;   b. forming high strength beverage end shells from the aluminum alloy coil in a shell press operating at least at 180 strokes per minute to produce 4140 shells per minute;   c. whereby, when the seamed can ends are fully aged, the aged ends satisfy a burst pressure specification of a minimum of at least 80 psi and an average of at least 90 psi.   
     
     
         2 . The method of  claim 1  further wherein the aluminum alloy has between 3.5% and 4.5% magnesium. 
     
     
         3 . The method of  claim 2  wherein the ends are configured such that the aged seamed ends satisfy a burst pressure specification of a minimum of at least 85 psi. 
     
     
         4 . The method of  claim 3  wherein the burst pressure specification requires substantially all the aged seams end to satisfy the minimum burst pressure requirement. 
     
     
         5 . The method of  claim 4  wherein satisfaction of the burst pressure specification requires commercial acceptance by a beverage company. 
     
     
         6 . The method of  claim 5  wherein the shell includes a center panel, a cover hook, and an inclined wall located between the center panel and a peripheral curl, the inclined wall is inclined at an inclined wall angle of at least 20 degrees from vertical. 
     
     
         7 . The method of  claim 6  wherein the shell further includes a countersink bead extending between the center panel and the inclined wall. 
     
     
         8 . The method of  claim 7  wherein the inclined wall is a multipart wall that extends between the countersink bead and the peripheral curl. 
     
     
         9 . The method of  claim 8  wherein the inclined wall includes an upper portion and a lower portion that are joined at a juncture, the upper portion is defined between a first point at an innermost point of the peripheral curl and the juncture, and the lower portion is defined between the juncture and a second point that is defined by an intersection of a horizontal projection from the plane of the center panel with the inclined wall or outer wall of the countersink bead. 
     
     
         10 . The method of  claim 9  wherein the inclined wall angle is measured between the first point and the second point. 
     
     
         11 . The method of  claim 10  wherein a lower wall angle measured between the second point and the juncture is at least 28 degrees. 
     
     
         12 . The method of  claim 11  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 32 degrees and approximately 55 degrees. 
     
     
         13 . The method of  claim 11  wherein the inclined wall angle is between approximately 25 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees. 
     
     
         14 . The method  claim 10  wherein a lower wall angle measured between the second point and the juncture is at least 33 degrees 
     
     
         15 . The method of  claim 14  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees. 
     
     
         16 . A system for manufacturing beverage end shells in commercial quantities from a coil of aluminum alloy sheet, comprising:
 a. a shell press operating at least at 180 strokes per minute producing at least 4140 beverage end shells per minute;   b. each shell:
 i. including a center panel, a cover hook, and an inclined wall located between the center panel and a peripheral curl, the inclined wall is inclined at an inclined wall angle of at least 20 degrees from vertical; and 
 ii. is formed of an aluminum alloy having between 3.0% and 4.5% magnesium; 
   c. whereby, when the seamed can ends are fully aged, the aged ends satisfy a burst pressure specification of a minimum of at least 80 psi and an average of at least 90 psi.   
     
     
         17 . The system of  claim 16  further wherein the aluminum alloy has between 3.5% and 4.5% magnesium. 
     
     
         18 . The system of  claim 17  further comprising a countersink bead extending between the center panel and the inclined wall. 
     
     
         19 . The system of  claim 18  wherein the inclined wall is a multipart wall that extends between the countersink bead and the peripheral curl. 
     
     
         20 . The system of  claim 19  wherein the inclined wall includes an upper portion and a lower portion that are joined at a juncture, the upper portion is defined between a first point at an innermost point of the peripheral curl and the juncture, and the lower portion is defined between the juncture and a second point that is defined by an intersection of a horizontal projection from the plane of the center panel with the inclined wall or outer wall of the countersink bead. 
     
     
         21 . The system of  claim 20  wherein the inclined wall angle is measured between the first point and the second point. 
     
     
         22 . The system of  claim 21  wherein a lower wall angle measured between the second point and the juncture is at least 28 degrees. 
     
     
         23 . The system of  claim 22  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 32 degrees and approximately 55 degrees. 
     
     
         24 . The system of  claim 22  wherein the inclined wall angle is between approximately 25 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees. 
     
     
         25 . The system of  claim 21  wherein a lower wall angle measured between the second point and the juncture is at least 33 degrees 
     
     
         26 . The system of  claim 25  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees. 
     
     
         27 . Plural beverage can end shells formed in a commercial shell press operating at least at 180 strokes per minute and at least 4140 shells per minute, each one of the plural shells comprising:
 a center panel, a cover hook, and an inclined wall located between the center panel and a peripheral curl, the inclined wall is inclined at an inclined wall angle of at least 20 degrees from vertical;   the shell formed of an aluminum alloy having between 3.0% and 4.5% magnesium;   whereby, when the seamed can ends are fully aged, the aged ends satisfy a burst pressure specification of a minimum of at least 80 psi and an average of at least 90 psi.   
     
     
         28 . The shells of  claim 27  further wherein the aluminum alloy has between 3.5% and 4.5% magnesium. 
     
     
         29 . The shells of  claim 28  further comprising a countersink bead extending between the center panel and the inclined wall. 
     
     
         30 . The shells of  claim 29  wherein the inclined wall is a multipart wall that extends between the countersink bead and the peripheral curl. 
     
     
         31 . The shells of  claim 30  wherein the inclined wall includes an upper portion and a lower portion that are joined at a juncture, the upper portion is defined between a first point at an innermost point of the peripheral curl and the juncture, and the lower portion is defined between the juncture and a second point that is defined by an intersection of a horizontal projection from the plane of the center panel with the inclined wall or outer wall of the countersink bead. 
     
     
         32 . The shells of  claim 31  wherein the inclined wall angle is measured between the first point and the second point. 
     
     
         33 . The shells of  claim 32  wherein a lower wall angle measured between the second point and the juncture is at least 28 degrees. 
     
     
         34 . The shells of  claim 33  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 32 degrees and approximately 55 degrees. 
     
     
         35 . The shells of  claim 34  wherein the inclined wall angle is between approximately 25 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees. 
     
     
         36 . The shells of  claim 31  wherein a lower wall angle measured between the second point and the juncture is at least 33 degrees 
     
     
         37 . The shells of  claim 36  wherein the inclined wall angle is between approximately 23 degrees and approximately 60 degrees and the lower wall angle is between approximately 34 degrees and approximately 53 degrees.