Aluminum-alloy sheet

Patent metadata

Field	Value
Publication number	US-11591674-B2
Application number	US-202017065995-A
Country	US
Kind code	B2
Filing date	Oct 8, 2020
Priority date	Oct 9, 2019
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

An aluminum-alloy sheet has a chemical composition containing Si: 2.3-3.8 mass %, Mn: 0.35-1.05 mass %, Mg: 0.35-0.65 mass %, Fe: 0.01-0.45 mass %, and at least one element selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %. The ratio of the Si content to the Mn content is 2.5 or more and 9.0 or less. The aluminum-alloy sheet exhibits an elongation of 23% or more and a strain hardening exponent of 0.28 or more at a nominal strain of 3%. Such an aluminum-alloy sheet is well suited for press forming (stamping) applications, such as forming automobile body panels.

First claim

We claim:

1. An aluminum-alloy sheet comprising:
Si: 2.3-3.8 mass %,
Mn: 0.35-1.05 mass %,
Mg: 0.35-0.65 mass %,
Fe: 0.01-0.45 mass %, and
at least one element selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %,
wherein the aluminum-alloy sheet has an Si/Mn mass ratio of 3.0-9.0, an elongation of at least 23%, and a strain hardening exponent of at least 0.28 at a nominal strain of 3%.

2. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet further contains Ni: 0.0050-0.15 mass %.

3. The aluminum-alloy sheet according to claim 2 , wherein the strain hardening exponent is at least 0.29 at a nominal strain of 3%.

4. The aluminum-alloy sheet according to claim 3 , wherein the aluminum-alloy sheet has a Cu content of 0.0010-0.20 mass %.

5. The aluminum-alloy sheet according to claim 3 , wherein the aluminum-alloy sheet has a Cu content of 0.10-0.20 mass %.

6. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet contains at least two elements selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %.

7. The aluminum-alloy sheet according to claim 6 , wherein the aluminum-alloy sheet further contains Ni: 0.0050-0.15 mass %.

8. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet contains Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %.

9. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet has an Si content of 2.4-3.6 mass %.

10. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet has an Mn content of 0.4-1.05 mass %.

11. The aluminum-alloy sheet according to claim 1 , wherein the Si/Mn mass ratio is 3.0-8.0.

12. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet has an Mg content of 0.4-0.6 mass %.

13. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet has an Fe content of 0.1-0.4 mass %.

14. The aluminum-alloy sheet according to claim 1 , wherein the aluminum-alloy sheet has a thickness of 0.8-2.5 mm.

15. An aluminum-alloy sheet comprising:
Si: 2.3-3.8 mass %,
Mn: 0.35-1.05 mass %,
Mg: 0.35-0.65 mass %,
Fe: 0.01-0.45 mass %, and
at least one element selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %,
wherein the aluminum-alloy sheet has an Si/Mn mass ratio of 2.5-9.0, an elongation of at least 23%, and a strain hardening exponent of at least 0.28 at a nominal strain of 3%, and
the aluminum-alloy sheet is an automobile body panel.

16. The aluminum-alloy sheet according to claim 15 , wherein:
the automobile body panel is a three-dimensionally shaped product having a thickness of 0.8-2.5 mm; and
the Si/Mn mass ratio is 3.0-9.0.

17. A method for manufacturing the aluminum-alloy sheet according to claim 1 , comprising:
providing an aluminum alloy material that contains Si: 2.3-3.8 mass %, Mn: 0.35-1.05 mass %, Mg: 0.35-0.65 mass %, Fe: 0.01-0.45 mass %, and at least one element selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %, the aluminum alloy material having an Si/Mn mass ratio of 2.5-9.0;
hot rolling the aluminum-alloy material to form a sheet, the aluminum-alloy material being heated to 300-550° C. prior to hot-rolling and the hot-rolled sheet being at a temperature of 200-350° C. at the end of the hot rolling;
cold rolling the sheet formed by the hot rolling such that a total rolling reduction of the cold rolling is at least 50%;
subjecting the sheet formed by the cold rolling to a solution heat treatment in a temperature range of 480-560° C. and quenching at a cooling rate of at least 100° C./min until the sheet reaches 150° C.; and
after the solution heat treatment, subjecting the sheet to a pre-aging treatment in a temperature range of 50-150° C. for 1-100 hours;
wherein after the pre-aging, the aluminum alloy sheet exhibits an elongation of at least 23% and a strain hardening exponent of at least 0.28 at a nominal strain of 3%.

18. The method according to claim 17 , further comprising press forming the aluminum alloy sheet to form an automobile body panel.

19. An aluminum-alloy sheet produced by a process comprising:
providing an aluminum alloy material that contains Si: 2.3-3.8 mass %, Mn: 0.35-1.05 mass %, Mg: 0.35-0.65 mass %, Fe: 0.01-0.45 mass %, and at least one element selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %, the aluminum alloy material having an Si/Mn mass ratio of 3.0-9.0;
hot rolling the aluminum-alloy material to form a sheet, the aluminum-alloy material being heated to 300-550° C. prior to hot-rolling and the hot-rolled sheet being at a temperature of 200-350° C. at the end of the hot rolling;
cold rolling the sheet formed by the hot rolling such that a total rolling reduction of the cold rolling is at least 50%;
subjecting the sheet formed by the cold rolling to a solution heat treatment in a temperature range of 480-560° C. and quenching at a cooling rate of at least 100° C./min until the sheet reaches 150° C.; and
after the solution heat treatment, subjecting the sheet to a pre-aging treatment in a temperature range of 50-150° C. for 1-100 hours;
wherein after the pre-aging, the aluminum alloy sheet exhibits an elongation of at least 23% and a strain hardening exponent of at least 0.28 at a nominal strain of 3%.

20. The aluminum-alloy sheet according to claim 19 , wherein the aluminum-alloy sheet contains at least two elements selected from the group consisting of Cu: 0.0010-1.0 mass %, Cr: 0.0010-0.10 mass %, Zn: 0.0010-0.50 mass %, and Ti: 0.0050-0.20 mass %.

21. The aluminum-alloy sheet according to claim 20 , wherein the aluminum-alloy sheet further contains Ni: 0.0050-0.15 mass %.

22. The aluminum-alloy sheet according to claim 21 , wherein:
the aluminum-alloy sheet has a Cu content of 0.0010-0.20 mass %, an Si content of 2.4-3.3 mass %, an Mn content of 0.4-0.8 mass %, an Mg content of 0.4-0.6 mass %, and an Fe content of 0.1-0.4 mass %,
the Si/Mn mass ratio is 4.0-6.5;
the aluminum-alloy material is heated to 500-550° C. prior to the hot-rolling, the hot-rolled sheet being at a temperature of 280-350° C. at the end of the hot rolling;
the total rolling reduction of the cold rolling is at least 70%;
the solution heat treatment performed in a temperature range of 510-560° C.;
the strain hardening exponent after pre-aging is at least 0.29 at a nominal strain of 3%; and
the aluminum-alloy sheet is an automobile body panel.

23. The aluminum-alloy sheet according to claim 22 , wherein:
after the cold rolling, the aluminum-alloy sheet has a thickness of 0.8-2.5 mm; and
the aluminum-alloy sheet has been stamped into the form of a three-dimensionally shaped automobile body panel.

24. An automobile body panel produced by a process comprising:
stamping the aluminum-alloy sheet of claim 19 , to form a three-dimensionally shaped final product.

Assignees

• Uacj Corp
• Toyota Motor Co Ltd

Inventors

• Kuramoto Ryo
• Nagai Takeshi
• Masuda Yuya
• Ohno Kazutaka

Classifications

• C21D9/46

  for sheet metals · CPC title

• C22C1/026

  Alloys based on aluminium · CPC title

• C22C21/02 Primary

  with silicon as the next major constituent · CPC title

• C22F1/043 Primary

  of alloys with silicon as the next major constituent · CPC title

• C21D8/0236

  Cold rolling · CPC title