Aircraft Alloys

[JohnK]

Local museum/shop in the Cincinnati area restores and flies WW 2 warbirds. I heard someone talking about using 2024 and asked about its weldability. I was told that, yes, you don't want to weld it, but it spot welds well. Comments?

[Stillwelding]

How do you know the extent of the HAZ? It could be further then you think. From an engineering perspective, Leaving the part in the "as-welded" condition is useless, unless its spot or seam welding. 2024 is nothing new, its been worked, welded, formed, riveted and tested for over 65 years. If you want to find some interesting reading material, look for military aircraft welding handbooks from the 1950's. They typically cover OA, ARC, TIG, MIG, Laser, Spot, and ultrasonic welding, Steels, aluminums, magnesiums, alloy steels, cast materials etc, and interesting to see what processes they found to work the best on cetain materials etc. No offence to any of the welding equipment companies, but to me it seems like the modern welding books are more of an advertisement anymore, while maybe not directly. Even the newer AWS manuals, ever notice who sits on the board that writes them?

-Aaron

Amen Brother. Why do you think the Welding Journal is broken into two sections. One for advertisers to write about generalized welding content (can't promote your brand) and the other for grad students to publish their non editorial writings. If you'll notice, most of the editorial in any welding related publication that accepts advertising are not written by staff writers. I'll stick with the ASM Welding book.

[youfoundtheking]

I was under the impression that any aluminum would return to the 0 state in the area of the weld, is that not the case? I have a project comming up that I was going to use 6063 T52, I did all my strength calculations based on the metal in the annealed state.

Whoever said its not weldable probably oversimplified things a bit as the old books list it as being very weldable but useless in the as-welded condition. Sure you can weld it, but the base metal looses all its strength. The 2xxx series metals are heat treatable ( hence T3, T4 etc ), and most of the time they are used in some form of heat treated state. Welding ( except resistance ) usually leaves part of the HAZ in the "0" condition or close to it. In the old days, 2024 was torch welded, and re-heat treated all the time, so nothing special or new here. Same with Tig is done commonly today. Just welding it though leaves you with a very expensive piece of soft aluminum.
So sorry to say, your "new" technology is no better then anything else in this matter .

-Aaron

[Machinist]

I have some 2024-t4 body panels on a small race car.
I have welded some small tabs and such on them over the years
for a "quickie" type of repair or temporary mount for something
non-critical. All welds looked good and ALL cracked in 4-8
hours of running. For me welding on 2024 is just a smaller
cleaner version of duct tape!
Dave

Ductape = 200MPH TAPE

[Don52]

I was under the impression that any aluminum would return to the 0 state in the area of the weld, is that not the case?

After you weld the aluminum and let it sit, it will age and recover some of its strength, depending on the heat treat and alloy that you started with.

I have a project coming up that II was going to use 6063 T52, I did all my strength calculations based on the metal in the annealed state.

This is a reasonable assumption, but it is conservative. Take a look at the attached figure. The graph shows the increase in strength of the heat affected zone as a result of Post-Weld Aging of 6061-T4 and 6061-T6. The Post-Weld Aged 6063-T52 would also increase in strength. You will also see the following:

-If you weld 6061-T6 aluminum the as welded strength (AW) is weaker than the as welded strength of 6061-T4.
-After the weldment is Post-Weld Aged (PWA). The 6061-T4 will recover more strength and actually be stronger than the Post-Weld Aged 6061-T6.
-For this example the weakest point is 0.5 cm from the fusion zone.
-Both the 6061-T6 and the 6061-T4 did get stronger as a result of Post-Weld aging.

From: The Aluminum Association "Welding Aluminum: Theory and Practice" 1991 page 3.14 Volume #23.