Method of producing aluminum can sheet

Abstract

A method for producing aluminum can sheet includes the steps of providing a body made of an aluminum alloy type AA3004, AA3104 or other aluminum alloy suitable for making aluminum can sheet; homogenizing the body at a homogenization temperature of about 525° C. or less; hot rolling the homogenized body in a single stand hot rolling mill to produce a hot rolled sheet, said hot rolled sheet exiting the single stand hot rolling mill at a hot rolling exit temperature lower than the hot rolling starting temperature with a hot mill exit gauge; annealing the sheet to form a recrystallized hot rolled sheet; and cold rolling the recrystallized annealed sheet to apply a cold reduction to produce a cold rolled sheet with a final gauge.

1 . A method for producing aluminum can sheet comprising:
 providing a body made of an aluminum alloy type AA3004, AA3104 or other aluminum alloy suitable for making aluminum can sheet;   homogenizing the body at a homogenization temperature of about 525° C. or less;   hot rolling the homogenized body in a single stand hot rolling mill to produce a hot rolled sheet, said hot rolled sheet exiting the single stand hot rolling mill at a hot rolling exit temperature lower than a hot rolling starting temperature with a hot mill exit gauge;   annealing the sheet to form a recrystallized hot rolled sheet,   cold rolling the recrystallized annealed sheet to apply a cold reduction to produce a cold rolled sheet with a final gauge.   
     
     
         2 . The method according to  claim 1 , wherein the homogenization is carried out in a homogenization temperature range of 460° C. to 525° C., preferably with holding times between about 1 hour and about 22 hours holding time. 
     
     
         3 . The method according to  claim 1 , wherein the aluminum alloy comprises the following chemical composition: about 0.05-0.60 wt % Si (Silicon), preferably 0.15-0.5 wt % Si; about 0.10-0.80 wt % Fe (Iron), preferably 0.45-0.70 wt % Fe; about 0.70-1.50 wt % Mn (Manganese), preferably 0.80-1.40 wt % Mn; about 0.80-1.50 wt % Mg (Magnesium), preferably 0.90-1.30 wt % Mg; about 0.05-0.25 wt % Cu (Copper), preferably 0.10-0.25 wt % Cu; up to 0.10 wt % Ti (Titanium); up to 0.25 wt % Zn (Zinc); and up to 0.15 wt % impurities, preferably each of the impurities with less than 0.05 wt %; with the remainder as Al (Aluminum). 
     
     
         4 . The method of  claim 3 , wherein the aluminum alloy comprises at least 0.6 wt % Fe, preferably more than 0.6 wt % Fe and/or 0.6 wt % Fe or more. 
     
     
         5 . The method according to  claim 1 , wherein the aluminum alloy comprises:
 about 0.20-0.40 wt % Si, preferably about 0.30 wt % Si;   about 0.80-1.20 wt % Mn, preferably about 0.90 wt % Mn;   about 0.90-1.40 wt % Mg, preferably about 1.20 wt % Mg;   about 0.10-0.25 wt % Cu, preferably about 0.17 wt % Cu, and   about 0.55-0.70 wt % Fe, preferably about 0.60 wt % Fe.   
     
     
         6 . The method according to  claim 1 , wherein the step of providing a body made of an aluminum alloy comprises forming an aluminum alloy based on a composition comprising 80% or more aluminum scrap. 
     
     
         7 . The method according to  claim 1 , wherein the step of annealing the sheet includes selectively self-annealing or furnace annealing the sheet to form a recrystallized hot rolled sheet, wherein
 (i) the sheet is self-annealed to a recrystallized annealed state while being coiled in the single stand reversing mill if the hot rolling exit temperature equals or exceeds a threshold temperature;   (ii) the hot rolled sheet is transferred from the single stand reversing mill to a batch furnace and annealed in the batch furnace at an annealing temperature in a range at or above the hot rolling exit temperature to allow recrystallization of the hot rolled sheet to obtain a recrystallized annealed sheet, if the hot rolling exit temperature is below the threshold temperature   
     
     
         8 . The method of  claim 7 , wherein the threshold temperature is 330° C. 
     
     
         9 . The method of  claim 3 , wherein hot rolling includes a number of flat passes followed by a number of coiling passes. 
     
     
         10 . The method of  claim 9 , wherein the material temperature after the last flat pass is between 290° C. and 350° C. 
     
     
         11 . The method of  claim 9 , wherein the material temperature is in a range between about 220° C. and about 280° C. in all coiling passes.