Method for the manufacture of an aluminum sheet product from used beverage containers
An aluminum alloy and recycle method are provided in which the recycled used beverage containers form an alloy composition useful with relatively minor compositional adjustments for body stock.
1. A method, comprising:
forming a molten aluminum feedstock comprising at least about 65 wt. % used beverage containers, the used beverage containers having a body and an end, the end comprising a connector to a tab for opening the container, wherein the aluminum alloy of the body and the aluminum alloy of the end each comprise from about 0.55 to about 0.90 wt. % manganese, and wherein the aluminum alloy of the end has a higher magnesium concentration than the aluminum alloy of the body;
casting the molten aluminum feedstock to form a cast sheet; and
forming the cast sheet into an aluminum alloy sheet product.
2. The method recited in claim 1 , wherein the aluminum alloy of the body and the aluminum alloy of the end have a difference in manganese concentration of not greater than about 0.1 wt. %.
3. The method recited in claim 1 , wherein the aluminum alloy of the body comprises from about 1.4 wt. % to about 1.8 wt. % magnesium.
4. The method recited in claim 3 , wherein the aluminum alloy of the body comprises from about 1.5 wt. % to about 1.7 wt. % magnesium.
5. The method recited in claim 3 , wherein the aluminum alloy of the body comprises from about 0.22 wt. % to about 0.29 wt. % silicon, from about 0.33 wt. % to about 0.39 wt. % iron and from about 0.28 wt. % to about 0.33 wt. % copper.
6. The method recited in claim 1 , wherein the aluminum alloy of the end comprises from about 3.25 wt. % to about 5 wt. % magnesium.
7. The method recited in claim 6 , wherein the aluminum alloy of the end comprises from about 3.4 wt. % to about 4.25 wt. % magnesium.
8. The method recited in claim 6 , wherein the aluminum alloy of the end comprises from about 0 wt. % to about 0.2 wt. % silicon, from about 0 wt. % to about 0.29 wt. % iron, and from about 0.09 wt. % to about 0.11 wt. % copper.
9. The method recited in claim 1 , wherein the step of forming the molten aluminum feedstock comprises forming the molten aluminum feedstock from at least about 75 wt. % used beverage containers.
10. The method recited in claim 1 , wherein the step of forming the molten aluminum feedstock comprises forming the molten aluminum feedstock from at least about 85 wt. % used beverage containers.
11. The method recited in claim 1 , wherein the step of forming the molten aluminum feedstock comprises forming the molten aluminum feedstock from not greater than about 20 wt. % prime aluminum.
12. The method recited in claim 1 , wherein the step of forming the molten aluminum feedstock comprises forming the molten aluminum feedstock from not greater than about 10 wt. % prime aluminum.
13. The method recited in claim 1 , wherein the step of forming the molten aluminum feedstock comprises adding magnesium to the molten aluminum feedstock.
14. The method recited in claim 13 , wherein the step of forming the cast sheet into an aluminum alloy sheet product comprises the steps of:
hot rolling the cast sheet to form a hot rolled cast sheet;
cold rolling the hot rolled cast sheet to form a cold rolled sheet; and
annealing the cold rolled sheet to form the aluminum alloy sheet product,
wherein the aluminum alloy sheet product has a yield strength of at least about 15 ksi and a tensile strength of at least about 22 ksi.
15. The method recited in claim 1 , wherein the step of forming the cast sheet into an aluminum alloy sheet product comprises the steps of:
hot rolling the cast sheet to form a hot rolled cast sheet;
first annealing the hot rolled cast sheet to form a first annealed cast sheet;
first cold rolling the first annealed cast sheet to form a first cold rolled sheet;
second annealing the first cold rolled sheet to form a second annealed cast sheet,
second cold rolling the second annealed cast sheet to form a second cold rolled cast sheet; and
third annealing the second cold rolled cast sheet to from the aluminum alloy sheet product,
wherein the aluminum alloy sheet product has a yield strength of at least about 11 ksi and a tensile strength of at least about 11 ksi.