Pie plate sheet and method of manufacturing

Abstract

A monolithic container having a bottom wall, a sidewall interconnected to the bottom wall and extending upwardly and outwardly therefrom to define an open end of the monolithic container at an upper edge of the sidewall, the sidewall having a peripheral flange extending outwardly from the upper edge. The monolithic container formed from an aluminum alloy feedstock comprising: from about 0.05 to 0.55% by weight silicon, from 0.10 to about 0.50% by weight iron, from less than about 0.60% by weight copper, from about less than about 0.4% by weight manganese, from about 0.9 to about 1.8% by weight magnesium, with the balance being aluminum and impurities. The aluminum alloy feed stock used to form the container has a gauge of less than about 0.008 inch.

What is claimed is:  
     
         1 . A monolithic smooth-walled container having a bottom wall, a sidewall interconnected to said bottom wall and extending upwardly and outwardly therefrom to define an open end of said monolithic container at an upper edge of said sidewall, said sidewall having a peripheral flange extending outwardly from said upper edge, said monolithic container formed from an aluminum alloy feedstock comprising: 
 from about 0.05 to 0.55% by weight silicon,    from 0.10 to about 0.50% by weight iron,    up to about 0.60% by weight copper,    up to about 0.4% by weight manganese,    from about 0.90 to about 1.8% magnesium,    with the balance being aluminum and impurities.    
     
     
         2 . The monolithic smooth-walled container of  claim 1  in which said composition further comprises: 
 from about 0.05 to 0.55% by weight silicon,  
 from 0.10 to about 0.50% by weight iron,  
 from less than about 0.60% by weight copper,  
 from about less than about 0.4% by weight manganese,  
 from about 0.9 to about 1.8% by weight magnesium,  
 with the balance being aluminum and impurities.  
 
     
     
         3 . The monolithic smooth-walled container of  claim 1  in which said composition further comprises: 
 up to 0.05% by weight chromium,  
 up to 0.05% by weight nickel, and  
 up to 0.05% by weight zinc.  
 
     
     
         4 . The monolithic contain of  claim 1  in which said aluminum alloy feed stock has a gauge of less than about 0.008 inch.  
     
     
         5 . A method for manufacturing of aluminum alloy open-ended food container, said method comprising: 
 (a) manufacturing food container stock in a continuous in-line sequence, said manufacturing comprising: 
 (1) providing an aluminum alloy feedstock from a composition comprising: 
 from about 0.05 to 0.55% by weight silicon,  
 from 0.10 to about 0.50% by weight iron,  
 from less than about 0.60% by weight copper,  
 from about less than about 0.4% by weight manganese,  
 from about 0.9 to about 1.8% by weight magnesium,  
 with the balance being aluminum and impurities.  
 
 (2) hot rolling said aluminum alloy feedstock to hot reduce its thickness;  
 (3) annealing and solution heat treating said hot reduced feedstock without intermediate cooling while maintaining the temperature of said hot reduced feedstock for a time and level sufficient to retain alloying elements in solution; and  
 (4) rapidly quenching said heat treated feedstock to a temperature for cold rolling; and  
   (2) shaping said heat treated feedstock into an open-ended food container.    
     
     
         6 . A method as defined in  claim 4  wherein the feedstock is provided by continuous strip or slab casting.  
     
     
         7 . A method as defined in  claim 4  wherein the feedstock is formed by depositing molten aluminum alloy on an endless belt formed of a heat conductive material whereby the molten metal solidifies to form a cast strip, and the endless belt is cooled when it is not in contact with the metal.  
     
     
         8 . A method as defined in  claim 4  which includes, as a continuous in-line step, cold rolling the quenched feedstock.  
     
     
         9 . A method as defined in  claim 4  in which includes the further step of forming pie pans from the cold rolled sheet stock.  
     
     
         10 . A method as defined in  claim 4  in which includes the step of coiling the cold rolled feedstock after cold rolling.  
     
     
         11 . A method as defined in  claim 9  wherein the coiling of the cold rolled sheet stock is in-line.  
     
     
         12 . A method as defined in  claim 4  wherein the hot reduced feedstock is heated to a temperature within the range of 680° F. up to the solidus temperature of the feedstock.  
     
     
         13 . A method as defined in  claim 4  wherein the annealing and solution heat treating is performed in-line at a temperature approximately the same as the hot rolling exit temperature for a period of time provided by a holding means.  
     
     
         14 . A method as defined in  claim 4  wherein the hot rolling of the feedstock is carried out at an exit temperature within the range of 680° F. to 780° F.  
     
     
         15 . A method as defined in  claim 4  wherein the warm rolling of the feedstock is carried out at a temperature within the range of 530° F. to 680° F.  
     
     
         16 . A method as defined in  claim 4  wherein the cold rolling of the feedstock is carried out at a temperature within the range of 300° F. to 4500° F.  
     
     
         17 . A method as defined in  claim 4  wherein the cold rolling step effects a reduction in the thickness of the feedstock of 20 to 75%.  
     
     
         18 . A method for manufacturing aluminum alloy open-ended food container sheet comprising the following steps in continuous, in-line sequence: 
 (a) strip or slab casting a open-ended food container aluminum alloy to form an aluminum alloy strip or slab;    (b) hot rolling said strip or slab to reduce its thickness at a temperature within the range of about 680° F. to about 900° F.;    (c) warm rolling said strip or slab to reduce its thickness at a temperature within the range of about 530° F. to about 680° F.; and    (d) cold rolling said strip to final guage at a temperature within the range of about 300° F. to about 450° F.    
     
     
         19 . A method as defined in  claim 17  in which includes the step of coiling the aluminum alloy strip after cold rolling.  
     
     
         20 . A method as defined in  claim 17  in which includes the step of coiling the aluminum alloy strip after cold rolling and annealing said coil said strip at a temperature of at least 625° F. for at least 2 hours.  
     
     
         21 . A method as defined in  claim 17  wherein the width of the feedstock is less than 24 inches.  
     
     
         22 . The method of  claim 17  in which said aluminum alloy comprises: 
 from about 0.05 to 0.55% by weight silicon,  
 from 0.10 to about 0.50% by weight iron,  
 up to about 0.60% by weight copper,  
 up to about 0.4% by weight manganese,  
 from about 0.90 to about 1.8% magnesium,  
 with the balance being aluminum and impurities.