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Minimum Bend Radius for 2024-T3 Alumuminum

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MichaelHill

Aerospace
Aug 31, 2014
2
I'm trying to figure out if how our shop's been bending 0.050" 2024-T3 is truly the way we should be doing it. We bend it with a 0.125" radius, but checking out a lot of other sources say we should be bending it with a 0.160-0.170 radius, but I'm not sure if those are specific for aerospace applications. This will be used for a robotic application. I wasn't sure if the larger bend radii are some FAA mandated thing or what. The Machinery's Handbook was of no help (oddly enough). It just says Rmin = T*(50/r - 1) where T = thickness and r = "percentage reduction in a tensile test for a given material (%)" with no explanation. So I have no real idea what "r" actually is.

Thanks,
Mike
 
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That was one of the sites I was referring to. Note it says "The bend radii listed are standard minimum if manufacturing for aircraft and aerospace applications."

I don't have to conform to aircraft or aerospace regulations for this application.
 
Hi

I was always taught never to use a bend radius tool less than the thickness of the material I was bending, I don't think you have a problem because it says minimum.
Obviously if you have cracking on the outside face then you need to look at the bend radius.
 
bigger bend radius is fine. the minimum is typically 3t. you can go less (1t) if you form in O-condition, and then heat treat to T3, and then straighten out the parts again !.

bending 0.05" on a 0.25" form is fine.

Quando Omni Flunkus Moritati
 
Depends on if you are bending with the grain or against it. The Aluminum Association has recommended radii but the aerospace industry may have different ( I hope more conservative ) numbers.
 
Different grades and tempers of Al bend differently, so be careful. I use 3T for bends in 2024T3 so 0.050 * 3 = 0.150 to be exact. If you can get 0.156" dies you should be good, otherwise 0.25 is the safest bet.

If bending at 0.125 is usually working OK in your shop, that's not really a surprise. Just bear in mind that the cracks start very small when the bend is "marginal". You might not have failures in the shop but they may fail later in service.

I know... when I was a full time designer these generous allowances for bends cramped my style too.

STF
 
Michael Hill,
Alcoa Aluminum in their handbook " Forming Alcoa Aluminum" gives the following information : Approximate Radii for sheet and plate 90 degree bend, Alclad 2024 T3, 1/64"thick 1,5T to 3 T, 1/32nd thick 2T to 4 T, 1/16th thick 3T to 5 T, 1/8th thick 4T to 6T, where T is the thickness of metal.
B.E.

You are judged not by what you know, but by what you can do.
 
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