Method of manufacturing aluminum alloy sheet

Abstract

A method for manufacturing aluminum sheet stock that includes hot rolling an aluminum alloy feedstock to a final thickness and then back-annealing (or stress relieving or stabilizing) the hot rolled feedstock to provide an intermediate temper.

What is claimed is:  
     
         1 . A method for manufacturing of aluminum sheet stock, comprising: 
 casting an aluminum alloy feedstock from an aluminum alloy melt;    hot rolling the aluminum alloy feedstock to a finished gauge to form a hot rolled feedstock; and    back-annealing at least one of the aluminum alloy feedstock and hot rolled feedstock to provide a desired intermediate temper.    
     
     
         2 . A method as claimed in  claim 1 , wherein the feedstock is formed by continuous strip or slab casting.  
     
     
         3 . A method as claimed in  claim 1 , 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 a portion of the endless bolt is cooled when the portion is not in contact with the metal.  
     
     
         4 . A method as claimed in  claim 1 , wherein, in the back annealing step, the at least one of the aluminum alloy feedstock and hot rolled feedstock is only partially recrystallized.  
     
     
         5 . A method as claimed in  claim 1 , wherein the hot rolled feedstock is free of cold rolling after the hot rolling step.  
     
     
         6 . A method as claimed in  claim 1 , wherein the hot rolling step reduces the thickness of the aluminum alloy feedstock by from about 40 to about 99%.  
     
     
         7 . A method as claimed in  claim 1 , wherein the back-annealing step comprises the step of: 
 in-line heating of the hot rolled feedstock to a temperature above the output temperature from the hot rolling step.    
     
     
         8 . A method as claimed in  claim 1 , wherein the back annealing step occurs at least one of during and immediately after hot rolling.  
     
     
         9 . A method as claimed in  claim 1 , wherein, in the back annealing step, the recrystallization of the at least one of the aluminum alloy feedstock and hot rolled feedstock is no more than about 60%.  
     
     
         10 . A method as claimed in  claim 7 , wherein, in the back annealing step, the hot rolled feedstock is heated to a temperature within the range of about 600 to about 900° F.  
     
     
         11 . A method as claimed in  claim 1 , wherein, in the back annealing step, the at least one of the aluminum alloy feedstock and hot rolled feedstock is heated to a temperature within the range of about 700 degree to about 1000° F.  
     
     
         12 . A method as defined in  claim 1  wherein the exit temperature of the hot rolled feedstock from the hot rolling step ranges from about 300 to about 1000° F.  
     
     
         13 . A method as claimed in  claim 1 , wherein the residence time of a selected portion of the hot rolled strip in the back-annealing step is no more than about 120 seconds.  
     
     
         14 . A method as claimed in  claim 13 , wherein the residence time is no more than about 10 seconds.  
     
     
         15 . A method for manufacturing aluminum alloy sheet comprising the following steps in continuous, in-line sequence: 
 (a) continuously casting an aluminum alloy melt to form an aluminum alloy feedstock;    (b) hot rolling the aluminum alloy feedstock to form a hot rolled feedstock having an output temperature, wherein a thickness of the hot rolled feedstock is less than a thickness of the aluminum alloy feedstock;    (c) maintaining the temperature of the hot rolled feedstock at no less than about 50° F. less than the output temperature of the hot rolled feedstock; and    (d) heating the hot rolled feedstock to a temperature sufficient to back-anneal said hot rolled feedstock to form back-annealed feedstock, wherein a degree of recrystallization of the back-annealed feedstock after the back annealing step is no more than about 60%.    
     
     
         16 . A method as claimed in  claim 15 , wherein the hot rolled feedstock is free of quenching and cold rolling.  
     
     
         17 . A method as claimed in  claim 15 , wherein the back annealed-feedstock is free of further annealing.  
     
     
         18 . A method as claimed in  claim 15 , wherein the hot rolled feedstock is at finished gauge.  
     
     
         19 . A method as claimed in  claim 15 , wherein the back-annealed feedstock has an intermediate temper.  
     
     
         20 . A method as claimed in  claim 15 , wherein the aluminum alloy feedstock is one of a 1XXX, 3XXX, 5XXX, 7XXX, and 8XXX alloy.  
     
     
         21 . A method for manufacturing aluminum shoot stock comprising the following steps in a continuous, in-line sequence: 
 (a) one of strip and slab casting an aluminum alloy on at least one endless belt to form an aluminum alloy strip;    (b) hot rolling said strip to form a hot rolled strip having a thickness less than a thickness of the aluminum alloy strip; and    (c) immediately after hot rolling, heat treating said hot rolled strip at a temperature sufficient to provide a heat treated strip having an intermediate temper.    
     
     
         22 . A method as claimed in  claim 21 , wherein the hot rolled strip is free of quenching and cold rolling.  
     
     
         23 . A method as claimed in  claim 21 , wherein the heat treated strip is free of further annealing.  
     
     
         24 . A method as claimed in  claim 21 , wherein the hot rolled strip is at finished gauge after hot rolling is completed.  
     
     
         25 . A method as claimed in  claim 21 , wherein the back-annealed strip has an intermediate temper.  
     
     
         26 . A method as claimed in  claim 21 , wherein the aluminum alloy is one of a 1XXX, 3XXX, 5XXX, 7XXX, and 8XXX alloy.  
     
     
         27 . A method for manufacturing aluminum sheet stock comprising: 
 (a) continuously casting an aluminum alloy by depositing a molten alloy on at least one endless belt formed of a heat conductive material, whereby the molten metal solidifies on said belt to form a cast strip;    (b) hot rolling said cast strip to form a hot rolled strip having a thickness less than a thickness of the cast strip, wherein the hot rolled strip thickness is at finish gauge; and    (c) heat treating at least one of the cast strip and hot rolled strip to provide an intermediate temper to the at least one of the cast strip and hot rolled strip.    
     
     
         28 . A method as claimed in  claim 27 , wherein the steps are performed in a continuous, in-line sequence.