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Substituting 2024-T42 2

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coastie

Military
Dec 15, 2003
5
0
0
US
We have a repair scheme that calls for 2024-T42 0.040 Clad sheet. This temper is not readily available at our unit. Can T-3 be used as a substitute.
 
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Likely. Use the allowables in Mil-Hdbk-5 to determine if it's compatible with whatever you're doing with it. If stress-corrosion-cracking or fracture toughness are critical issues, look carefully at the differences (they might be the same). Does the repair scheme expect you to form the sheet in the O condition, and heat-treat it later?


"Simplicate, and add more lightness" - Bill Stout
Steven Fahey, CET
 
Yes, it was to be fabricated from O condition. The problem is having the oven to cook after fabrication. On that note is there a on-line location to find a heat treat recipe?
 
The spec QQ-A-250/5 (I think that's the number) lays out the process you need. You can get that from ASSIST: But you've lost me - do you want to cook your part or not?

It sounds like you don't have access to a heat-treating facility, and you want to use 2024-T3 to make the part right off the bat. You need to look at the drawing in detail to know if the -T3 can withstand the fabrication of the part. 2024 in the O condition can withstand sharp bends that you cannot reproduce with tempered -T3. If fabrication also involves unusual processes, like drawing, you will have stresses built into the part that won't ever go away, unless you start with 2024-O and heat treat afterward.

Take care now, not all breeds of 2024 are alike.



"Simplicate, and add more lightness" - Bill Stout
Steven Fahey, CET
 
Coastie,

Per most Structural Repair Manuals, T3 and T42 are interchangeable. The T0 (T zero) is formed as required and heat treated per MIL-H-6088 to T42. T3 is the temper as received from the mill.

Depending upon the bends and contours, you might or might not be able to form the T3 .040 as required, without cracking in the radius. That is why the repair is normally formed in T0, then heat treated to T42.

As an Avionics type in the Navy, I never really learned this well enough. And when I took over as Maintenance Chief, I didn't have a clue.

If you will give me your e-mail address, I will send you the Introduction section of the Aluminum Standards Manual which shows the Temper Information. Also the MIL-H-6088, is at the web site given by Sparweb, but I can send you this also.
Rerig
 
SPARWEB Thanks for your replies on this.

RERIG Thanks to you too! Please e-mail me at jking@arsc.uscg.mil with info. you suggested.
 
MIL-H-6088 is the heat treating spec used by the mills. For in-house heat treating of aluminum, the correct spec is AMS 2770.
Chuck
 
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