Sheet Metal Forming for Aircraft skins

[crystallographic]

Originally Posted by AllyBill

Not welded 7075 so can't comment there.
2024 can crack if you weld it in one of its higher tempers depending on what you are trying to do, don't for instance try to insert a circular patch, but when properly annealed it welds like any other grade and doesn't crack at all. When I say properly annealed I mean you take it to the heat treatment plant and have them do a full anneal and furnace cool, make your weld with strips of native material then have the heat treatment plant put the desired temper back. Never had a problem with it.

As a slight aside, the skins of the Handley-Page Victor wing were extensively spot-welded with no issues and they were 2024.

Will

Spot welding of 2024 T3 is very common on US airplanes. Going back to pre-WW2, many cowlings and "semi-structural" elements have been made using spot welding. One of the largest spot-welded airplane structural assemblies I have seen is the rear half fuselage of the Convair B36 "Peacemaker" - the behemoth that replaced the excellent Northrop YB49.
https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker

I have seen a ski-plane ski marked "24S" (pre-1953 designation for 2024 T3) and it was gas welded. I have not seen other examples of tig or gas welding of 2024 alloy in aircraft production. I do know that the Aluminum Association rates 2024 weldability as a "D" - compared to alloy 2219, a ballistic material used in the early A10 Warthogs as a welded tub to protect the pilot - later replaced by welded titanium.

This article I grabbed on a quick search describes fairly recent aluminum welding recommendations:
https://books.google.com/books?id=DZ...uminum&f=false
It does not mention 2024 as being weldable.

Rockmount Research, on the other hand, sells a filler metal designed for 2024 and has for many years. It's specific applications in aerospace are above my pay-grade. I believe the filler is designated as "Neptune TIG."

I heard some years back that Trek Bicycles (and maybe Cannondale?) had their weld engineers work out welding of 2024 for their bike frames. So far, I have not spoken to anyone there about that.

I guess the bottom line is that some can weld it, but at the levels of the Aluminum Association and their tech reps, welding 2024 is rated as a "D" - or as Paul Dickerson told me once, "Screw it!" ... or rivet or bolt or bond it.