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EP-4739810-A1 - METHODS OF PRODUCING 6XXX SERIES ALUMINUM ALLOYS AT THIN GAUGE

EP4739810A1EP 4739810 A1EP4739810 A1EP 4739810A1EP-4739810-A1

Abstract

Provided herein are highly-formable aluminum alloys and methods of making such alloys. The method of preparing aluminum alloys described herein can include a cold work thickness reduction subsequent to a solution heat treatment step to produce an aluminum alloy product exhibiting improved formability. The methods described herein result in the aluminum alloys having a relatively soft composition, enabling improved formability through reduced passes during hot mill rolling and cold mill rolling compared to conventional AA5182 aluminum alloys used to produce can end stock. Reducing the number of passes to produce an aluminum alloy product with a desirable gauge can reduce carbon emissions and energy consumption associated with producing the aluminum alloy product.

Inventors

  • MACIEJEWSKI, Joseph
  • PARK, Jaesuk
  • KANG, DaeHoon
  • WARNER, Jeffrey Samuel

Assignees

  • Novelis Inc.

Dates

Publication Date
20260513
Application Date
20240702

Claims (20)

  1. 1. A method of producing an aluminum alloy product, comprising: casting an aluminum alloy to produce a cast aluminum alloy product, wherein the aluminum alloy comprises a 6xxx series aluminum alloy; homogenizing the cast aluminum alloy product to produce a homogenized cast aluminum alloy product; hot rolling the homogenized cast aluminum alloy product to produce a hot rolled product; optionally, i) solution heat treating the hot rolled product at a solution heat treatment temperature of about 450 °C to 600 °C; or ii) coiling the hot rolled product at a hot rolling exit temperature; cold rolling the hot rolled product to produce a cold rolled product, wherein the cold rolled product is rolled to a final gauge thickness from 0.180 mm to 0.250 mm, wherein an exit temperature of the cold rolled product is 150 °C or greater; and optionally, solution heat treating the cold rolled product at a solution heat treatment temperature of about 450 °C to 580 °C.
  2. 2. The method of claim 1, further comprising: coiling the cold rolled product to produce a coiled aluminum alloy product, wherein the cold rolled product is configured to undergo precipitation hardening during and/or after coiling.
  3. 3. The method of claim 2, further comprising coating the coiled aluminum alloy product.
  4. 4. The method of claim 1, wherein the cast step comprises direct chill casting.
  5. 5. The method of claim 1, wherein coiling the hot rolled product at the hot rolling exit temperature comprises maintaining the hot rolled product at the hot rolling exit temperature during coiling or coiling the hot rolled product initially at the hot rolling exit temperature as the hot rolled product cools to a cold rolling temperature.
  6. 6. The method of claim 1, wherein the aluminum alloy product comprises 0.20 - 1.40 wt. % Si, 0.20 - 0.80 wt. % Fe, 0.05 - 1.00 wt. % Cu, 0.05 - 0.80 wt % Mn, 0.50 - 1.60 wt. % Mg, up to 0.25 wt. % Zn, up to 0.30 wt. % Cr, up to 0.60 wt. % Bi, up to 0.60 wt. % Pb, up to 0.15 wt. % impurities, and the remainder Al.
  7. 7. The method of claim 1, wherein the homogenizing step is performed at a homogenization temperature from about 540 °C to 600 °C.
  8. 8. The method of claim 1, wherein the hot rolled product is cooled to about ambient temperature prior to the solution heat treating step.
  9. 9. The method of claim 1, wherein the solution heat treating step comprises heating the hot rolled product at the solution heat treatment temperature for up to 50 seconds prior to the cold rolling step.
  10. 10. The method of claim 9, wherein a line speed of the solution heat treating step is at least 20 meters/min.
  11. 11. The method of claim 1, wherein an entry temperature of the hot rolled product to the cold rolling step is from 20 °C to 80 °C.
  12. 12. The method of claim 1, wherein the cold rolling step comprises 6 or fewer cold rolling passes to produce the cold rolled product.
  13. 13. The method of claim 1, wherein the method does not include artificial aging after the cold rolling step.
  14. 14. The method of claim 12, wherein the cold rolling step is performed in a cold rolling mill comprising at least two stands arranged in series.
  15. 15. The method of claim 12, wherein the cold rolling step comprises a single pass to produce the cold rolled product.
  16. 16. The method of claim 1, wherein the exit temperature of the cold rolled product is from about 150 °C to 220 °C.
  17. 17. The method of claim 1, wherein the cold rolling step produces at least 80% cold work thickness reduction from the hot rolled product to the cold rolled product.
  18. 18. The method of claim 17. wherein the cold rolling step produces a cold work thickness reduction from about 85% to 95%.
  19. 19. The method of claim 1, wherein the hot rolling step is configured to produce the hot rolled product having a hot band gauge of from about 0.5 mm to 3.5 mm.
  20. 20. The method of claim 1, wherein the hot rolling step is characterized by using 21 or fewer passes to produce the hot rolled product.

Description

METHODS OF PRODUCING 6XXX SERIES ALUMINUM ALLOYS AT THIN GAUGE CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of and priority to U.S. Provisional Application No. 63/511.819 filed July 3, 2023, which is incorporated herein by reference in its entirety for all intents and purposes. FIELD [0002] This disclosure relates to the fields of material science, material chemistry, metallurgy, aluminum alloys, aluminum alloy products, aluminum fabrication, and related fields. More specifically, the present disclosure relates to 6xxx series aluminum alloys that exhibit high strength and formability at thin gauges. The 6xxx series aluminum alloys having thin gauges can be used to produce, for example, can tabs, can bodies, and can ends for beverage cans. BACKGROUND [0003] Can end stock is conventionally made from high-strength aluminum alloys that have good formability properties. The mechanical requirements for aluminum alloys used to produce can end stock are different than the mechanical requirements for can body stock. In general, aluminum alloys for producing can end stock require greater strength than can body stock. As a result, can end stock is often fabricated from an aluminum alloy comprising high amounts of magnesium (Mg). For instance, can end stock may be fabricated from a highly engineered AA5182 aluminum alloy that has a rigidly controlled composition and process for producing the alloy. [0004] Many aluminum manufacturers use AA5182 aluminum alloy for can end stock. The AA5182 composition is strictly controlled to have a magnesium (Mg) content between 4.0 wt. % and 5.0 wt. %, a manganese (Mn) content between 0.2 wt. % and 0.5 wt. %, a maximum iron (Fe) content of 0.35 wt. %, a maximum silicon (Si) content of 0.2 wt. %, a maximum copper (Cu) content of 0.15 wt. %, and a maximum chromium (Cr) content of 0.1 wt. %. However, it is difficult to improve the performance of one property of a 5xxx series aluminum (e.g., strength) without decreasing the performance of another property (e.g., formability). If the Mg content of the AA5182 is increased above 5 wt. % to improve strength and/or formability, the aluminum alloy will be highly susceptible to cracking during the production process. Additionally, a relatively high Mg content can hinder recovery of the aluminum alloy, causing decreased reusability and recyclability of the aluminum alloy products. SUMMARY [0005] Covered embodiments of the invention are defined by the claims, not this summarv This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings, and each claim. [0006] Provided herein are highly-formable 6xxx series aluminum alloys and methods of producing the aluminum alloys at thin gauge. The aluminum alloys described herein comprise 0.20 - 1.40 wt. % Si. 0.20 - 0.80 wt. % Fe, 0.05 - 1.00 wt. % Cu, 0.05 - 0.80 wt. % Mn, 0.50 - 1.60 wt. % Mg, up to 0.25 wt. % Zn. up to 0.30 wt. % Cr, up to 0.60 wt. % Bi, up to 0.60 wt % Pb, up to 0. 15 wt. % impurities, and the remainder Al. In some embodiments, the aluminum alloys comprise 0.60 - 1.10 wt. % Si, up to 0.40 wt. % Fe, 0.50 - 0.90 wt. % Cu, 0.10 - 0.45 wt. % Mn, 0.50 - 1.00 wt. % Mg, up to 0.15 wt. % Zn, up to 0.10 wt. % Cr, up to 0.05 wt. % Bi, up to 0.05 wt. % Pb, up to 0.15 wt. % impurities, and the remainder Al. [0007] In some embodiments, a method of producing an aluminum alloy product is provided. The method includes: casting an aluminum alloy to produce a cast aluminum alloy product, wherein the aluminum alloy comprises a 6xxx series aluminum alloy; homogenizing the cast aluminum alloy product to produce a homogenized cast aluminum alloy product; hot rolling the homogenized cast aluminum alloy product to produce a hot rolled product; optionally, i) solution heat treating the hot rolled product at a solution heat treatment temperature of about 450 °C to 600 °C; or ii) coiling the hot rolled product at a hot rolling exit temperature; cold rolling the hot rolled product to produce a cold rolled product, wherein the cold rolled product is rolled to a final gauge thickness from 0.180 mm to 0.250 mm, wherein an exit temperature of the cold rolled product is 150 °C or greater; and optionally, solution heat treating the cold rolled product at a solution heat treatment temperature of about 450 °C to 580 °C. [0008] In some embodiments, the method further comprises coiling the cold rolled product to produce a coiled aluminum alloy product, wherein the cold rolled product is configured to undergo precipitation hardening during coil cooling. In