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Fabman
03-20-2010, 12:29 PM
I remember someone on this site talking about experience with heat treating 2024. I searched for the thread with no results. If any one has experience with this please send me a PM.

Iflylower
03-20-2010, 11:35 PM
There was a guy Don - structures engineer for L3 aviation in East Texas - at Steve Pierces first weekend Seminar.

Just from speaking with him and hearing him, he would probably know what you need. He was very knowledgeable with heat treating and anodizing aluminum of all grades.

Really helpful and EAA tech councilor. I'm sure he'd love to solve your problem.

Pierce would know how to reach him. Or maybe Jason Gerard, I think he may have taken the Stewarts fabric class, and left a contact trail.

Fabman
03-21-2010, 12:38 AM
Thanks for the info Iflylower.

mike mcs repair
03-21-2010, 12:46 AM
might try someone on the base here,

10 years ago or so I knew of someone having stuff done there... not sure if that was a sanctioned thing of course....

Steve Pierce
03-21-2010, 06:50 AM
Don, I can find out tomorrow. The warbird shop I used to work in hydroforms stuff out of 2024-O and then gets it heat treated.

aktango58
03-21-2010, 08:56 AM
Not simple.

it is time and temperature sensitive, ie: heat to x degrees for 2 hours, reduce heat by x and hold at temp for x hours and on and on.

I used a shop in Auburn WA and they did a great job, annealed it, then back up to T3 after it was bent.

lytlej
03-21-2010, 10:25 AM
2024 is a precipitation-hardening alloy, with the main alloying ingredient being copper (4% or so, but I'm working from memory on that one). The strength comes by forming submicroscopic precipitates of the Cu-Al intermetallic; strength increases as these particles grow. The local straining gives the properly-treated alloy its strength. If they grow too large, they lose coherency with the surrounding aluminum and the strength decreases rapidly.

So--you must first dissolve the copper completely by holding at a high temperature for awhile; this is called solution treating. Then hold at a lower temperature, where the Cu-Al starts to precipitate. (A rough analogy: fog or rain forms when temperature drops below dew point). This is called precipitation hardening. But don't hold it too long, because it will then lose strength when the particles grow too large (called over-aging).

It is very empirical. A heat-treat shop will know exactly what temperature and time will give maximum strength. (The designations T3, T6, etc. refer to specific temperatures, times, and strengthening mechanisms that result).

Sorry for the long-winded discussion. It dredges up memories from a previous life and career, before I started disappearing frequently to go fly when dispatch called.

palhal
03-21-2010, 10:48 AM
Don---I made a large 2024 wing rib for a fighter and took it to a heat treat place and waited for it with my form pattern and some clamps. After it was finished it is slightly deformed and still just as soft, so I imediately put it back on the form and clamped it all down in place.

If I remember it takes a week or two to get hard and it came out great.

gander
03-21-2010, 10:57 AM
2024 is already heat treated. Normally you would use type 0 then heat treat it.