Heat treatment to improve joinability of aluminum sheet

Patent metadata

Field	Value
Publication number	US-2015125713-A1
Application number	US-201414189050-A
Country	US
Kind code	A1
Filing date	Feb 25, 2014
Priority date	Nov 1, 2013
Publication date	May 7, 2015
Grant date	—

Abstract

In at least one embodiment, an assembly is provided comprising a first member including a 6xxx series aluminum alloy heat treated to have a yield strength of at least 200 MPa and an r/t (bendability) ratio of up to 0.4. One or more members may be secured to the first member with a rivet (e.g., a self-piercing rivet). The heat treated alloy may have a yield strength of at least 260 MPa and may have a bendability ratio of up to 0.3. A method of forming an assembly is also provided, including heat treating a 6xxx series aluminum alloy to produce an alloy having a yield strength of at least 200 MPa and an r/t (bendability) ratio of up to 0.4 and riveting a member including the heat treated alloy to one or more additional members.

First claim

1 . An assembly comprising:
a first member including a 6xxx series aluminum alloy heat treated to have a yield strength of at least 200 MPa and an r/t (bendability) ratio of up to 0.4; and a rivet securing the first member to one or more additional members.

2 . The assembly of claim 1 , wherein the rivet maintains intimate contact with the 6xxx series aluminum alloy.

3 . The assembly of claim 1 , wherein the rivet is a self-piercing rivet (SPR).

4 . The assembly of claim 3 , wherein a button formed by the SPR is formed in the 6xxx series aluminum alloy.

5 . The assembly of claim 4 , wherein there is substantially no cracking in the button.

6 . The assembly of claim 1 , wherein the 6xxx series aluminum alloy has an r/t ratio of up to 0.3.

7 . The assembly of claim 1 , wherein the 6xxx series aluminum alloy is a 6061 alloy or a 6111 alloy.

8 . The assembly of claim 1 , wherein the 6xxx series aluminum alloy has been heat treated to a T7 or T8 temper.

9 . (canceled)

10 . The assembly of claim 1 , wherein the first member and the one or more additional members are each formed of a 6xxx series aluminum alloy heat treated to have a yield strength of at least 200 MPa and an r/t (bendability) ratio of up to 0.4.

11 . The assembly of claim 1 , wherein the first member and the one or more additional members each have a thickness of 0.8 to 4 mm are vehicle body panels.

12 . A method of joining an aluminum alloy to an automotive assembly, comprising:
heat treating a 6xxx series aluminum alloy at a temperature of 220° C. to 240° C. for from 30 minutes to 7 hours to produce an alloy having a yield strength of at least 200 MPa and an r/t (bendability) ratio of up to 0.4; and riveting a first member including the heat treated alloy to one or more additional members.

13 . The method of claim 12 , wherein the riveting step includes riveting the first member to the one or more additional members using a self-piercing rivet (SPR).

14 . The method of claim 12 , wherein the heat treating step has a duration of 5 to 7 hours.

15 . The method of claim 14 , wherein the heat treating step includes heat treating the 6xxx series aluminum alloy to a T7 temper having an r/t ratio of up to 0.3.

16 . The method of claim 12 , wherein the heat treating step has a duration of 30 to 90 minutes.

17 . The method of claim 16 , wherein the heat treating step includes heat treating the 6xxx series aluminum alloy to a T8 temper having a yield strength of at least 260 MPa.

18 . A pickup truck body member joint comprising:
a first member including a 6 xxx series aluminum alloy heat treated to have a yield strength of at least 200 MPa and an r/t ratio of up to 0.4; and one or more additional members secured to the first member with a self-piercing rivet (SPR), the SPR extending through the one or more additional members and maintaining intimate contact with the 6xxx series aluminum alloy.

19 . The assembly of claim 18 , wherein a button is formed in the 6xxx series aluminum alloy and the SPR terminates in the button.

20 . The assembly of claim 18 , wherein the 6xxx series aluminum alloy has been heat treated to have a yield strength of at least 260 MPa.

21 . The assembly of claim 18 , wherein the first member and the one or more additional members are pickup truck body panels.

Assignees

• Ford Global Tech Llc

Inventors

• Harrison Nia R
• Luckey Jr S George
• Boileau James Maurice
• Campbell Aindrea Mckelvey
• Freis Amanda Kay

Classifications

• C22F1/04 Primary

  of aluminium or alloys based thereon · CPC title

• C22C21/08

  with silicon · CPC title

• C22F1/047

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

• C22C21/02

  with silicon as the next major constituent · CPC title

• C22F1/05 Primary

  of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions · CPC title