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Annealing Aly 2024T3

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123Cat

Mechanical
Joined
Jul 16, 2003
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AU
It anneals at higher temps than the other alys
But at what temp
Thanks in advance
 
For full anneal (to T-0 temper): 2-3 hours at a metal temperature of 775oF (413 C), followed by slow cooling at 50oF/hr to 500oF. Faster cooling thereafter is permissible.
 
Thanks Ken
Yes I used 2011 for model eng heads and its apparently not the done thing
,,,,, so 2024 is the go
I think its the manganese and chrome which gives the 2024 the heat resistance over the others like 2011 and suchlike
Great
These air cooled engines run at approx 400F so I didnt think 2011 would be a prob
But apparently it is
 
Ken
I guess I should have asked at what temp does say,,,,,, aly 2011 start to lose its mechanical strength
That would be considerably lower than the annealing temp I guess
And thanks heaps
You guys are very impressive on my first post
Well done

By the by, con- rods in model engines are 2024 too
 
MIL-HDBK-5J METALLIC MATERIALS AND ELEMENTS FOR AEROSPACE VEHICLE STRUCTURES, a free (& huge) download at has data on the effect of temperature on the physical properties of Al 2024 but not 2011. For 1000 hours exposure, the yield strength of Al 2024 is down to ~87% at 300oF and 80% at 400oF.

For a comparison of the 2 alloys, the precipitation hardening temperature (to produce the T6 temper from solutionized alloy) is 320-340oF for 2011 vs. 375oF for 2024. Longer periods than the ~12 hour aging period (or higher temperatures) will cause overaging and loss of strength. Al 2024 has a significant advantage during long-term operation in the 300'soF, consistent with your observations.
 
Ken

You said for 1000 hours exposure the yield of 2024 aly is down to 80% at 400C

Does that mean its down to 80% yield immediatly the temp is 400C ????????

Thanks in advance
 
Not quite, yield stress = f(Temperature and time @ Temperature).
From MIL-HDBK-5J,
Figure 3.2.3.1.1(b). Effect of temperature on the tensile yield strength(Fty) of 2024-T3, T351, and 2024-T4 aluminum alloy (all products except extrusions).
[Curves are shown for 1/2, 10, 100, 1000 & 10,000 hours.]

At 400oF, yield strength as % of room T value:
1/2 hr 78%
10 76
100 70
1000 60
10,000 46
Note: these values are more accurate than in previous post where I read off monitor; these are from a printout.
 
Gee Thanks Ken

Well explained

 
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