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Thread: Heat treating Type O aluminium

  1. #1

    Join Date
    Oct 2011
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    Heat treating Type O aluminium

    I am using a lot of soft aluminum on a F4F rudder and h stab. (non airworthy aircraft) I would like to know if someone has references they can point me to, or experience in, heat treating to a Type 3 or so. The web has provided some info but it seems to be all over the map. So, if you have made a skin from soft material and thrown it in the over for 3 hours at 175 and then let it air cool please let me know the specifics. Thanks.

  2. #2

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    Jul 2011
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    The SRM for one of my projects gives 915F to 930F for air furnace heat treating 24SO ( old designation for 2024) to 24ST ( equavalent to 2024T3). Soak times range from 5 to 30 mins depending on material thickness once the part is completely at temp. Quench must be done within 8 seconds of removal from the furnace and there will need to be some straighening after quench.

    For doing it with gusto, the SRM also gives the procedures for saltbath heat treating too.

  3. #3

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    Well that is hot enough!

    Thanks for your response. 900F may be more than I can get. We currently have a large insulated box heated with a kerosene heater (those small jet engine looking things) and I am told it can get to 300 or so. I have a feeling that not too many people heat treat soft AL...

  4. #4

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    Nov 2011
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    Minnetonka MN
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    The solution heat treat process of 2024 T0 aluminum is to heat to 920 degF +/- 20 deg before a cold water quench.

    After the quench, if you can keep it in a deep freeze, it will still remain comparatively soft for a couple of days. This is called 2024 condition W.

    Once warmed or left at room temperature, it will be hard in a few of hours. This condition is called 2024 T42 aluminum. It will not quite have the physical properties of 2024 T3 but it is very close.

    This solution heat treat process with age hardening is comparatively distortion-free although the sheet metal parts we typically have may otherwise have allow a lot of distortion.

    I commercially heat treated .020 inch thick preformed ribs of T0 alum & had to beat the result over dies again to straighten the ribs out. Fortunately the heat treater kept the quenched parts in a deep freeze & I took them home in a styroform box with dry ice. At .032 inch thick the distortion was much less severe. I have a hunch that the pre-quench temperature is very critical and affects the amount of distortion greatly.

    If you have a large skin section formed of T0, distortion estimates will be off, as the water and steam forces will dominate the forming when at the quench temperature. Remember that the melting point of this alloy is on the order of less than 100 degreesF higher. This is nearly red heat.

  5. #5

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    Oct 2011
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    Well it appears I am destined to use soft AL or find an industrial oven. Any other suggestions that will allow me to use a lower temperature (kitchen oven type temps) is welcome. Thank you.

  6. #6
    I see this thread is old but for what it's worth,
    last year I was looking for a way to make fuselage ribs for a Privateer restoration. I did not want to get involved in solution heat treat (920 oven) so I came up with using 0.050 6061-T4, forming it then bake at 350 for 8 hours to get to T6.

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