2024-T3 Heat treat. 3

[RoarkS]

So...

I have access to a heat treat oven. FINALLY!

I'm forming parts out of .032" 2024-0

Then want them heat treated to T3.

How. What document says exactly how to do it?

Anyone ever done it? Giving wing ribs a try.

 

[Sparweb]

Congratulations to you!

Now, do you have access to the SAE specs?
Mil-specs?
QQ-A specs?
To me, that's the "obvious" starting place.

I believe the finicky part is the solution, not the oven.

http://www.sparweb.ca

 

[rb1957]

AMS4037 or QQ-A-250/4 … from MMPDS (for 2024T3 sheet)

another day in paradise, or is paradise one day closer ?

 

[berkshire]

RoarkS.
There are also heat treat tables in Alcoa's book " Forming Alcoa Aluminum." I do not think you are going to get T3 which is an as supplied factory temper for heat treated and mechanically reworked, You are going the get T4 which is slightly less than T3 or you are going to have to go to T8 which is slightly more. Recommended thermal treatment solution heat treatment 920F degrees 10 mins for thin material, precipitation heat treat 375F for 11 to 13 hours depending on the temper you want. There are lots of foot notes on 2024 in Alcoa's book so tread lightly.
B.E.

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

 

[rb1957]

strictly he'd get T42 (nominally the same as T3)

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

RB'57 is correct...

User solution HT/quench/natural-aging*/NDI** [starting in -O, or any other temper]... results in -T42 temper which is ~= -T3 [-T3 is an OEM, ONLY, temper].
*~96-hrs

AMS2770 is the current/industry favored HT for aluminum alloys... but MIL-H-6088 [last Rev G] HEAT TREATMENT OF ALUMINUM ALLOYS was the HT process for decades. Go to

https://quicksearch.dla.mil/qsSearch.aspx

NOTES.
Aerospace heat treaters prefer HT/quench of raw [semi-trimmed blank] stock... then forming while in the unstable 'W' temper... then natural aging to -T42 . Lots of good reasons for setting up fab sequence this way.

IF your forming is not severe in -O temper, the process of SHT/quench/straightening parts in W temper then natural aging to -T42 starting in -O temper is usually satisfactory.

IF Your 2024 sheet material is clad aluminum, I'm pretty sure You are allowed to solution HT/quench ONLY one time.

** Hardness and conductivity testing is 'technically required' to validate response to HT. Even very small disturbances [temperature, miss-timing, etc] relative to established practices can cause HT failure.

NOTE. IF YOU CAN FIND A COPY... similar/acceptable methods for aluminum HT are presented in USAF T.O. 1-1A-9

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[rb1957]

damnit if Will doesn't have the answer !

but interesting, table 2 says 2024 sheet goes to T42 or T3, T361 if "Cold working subsequent to solution heat treatment and prior to any precipitation heat treatment is necessary."

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

rb'57...

Tempers -T3xxx and -T8xxx ae OEM tempers only.

Relatively equivalent tempers -T42 and -T62 are user/shop HT tempers ONLY.

Reason is simple: OEMS making material have rigorous control of every variable and produce consistent product [or at-leas should]. User-shops vary from 'tightly run ships' to 'wild-wild-west' [don't ask/don't tell] quality.

NOTE.
Whenever a permanent compressive or tensile strain is applied to the material [any heat treatable alloy], by the OEM, it is done-so [almost] immediately after quenching while in the unstable 'W' temper... which minimizes direction grain growth/distortion and produces a more uniform/straight/flat 'raw/finished material' with optimum fine grain over all. This sequencing of processes is very important for formed high strength 7xxx series aluminum parts with unique tempers for strength/toughness/corrosion resistance [-T77xx, etc]… since grain optimization is 'everything'... especially when retrogression HT/re-aging is employed for '-T6-like-strength' but with '-T7xxx equivalent SCC/EXCO/fatigue'.


Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[RoarkS]

Sounds like I'm getting T42! Ignorant assumption expecting to get T3 at the end.

Berkshire, "Forming Alcoa Aluminum" is on it's way.

I was not aware alclad could only be done once Thanks!

"Aerospace heat treaters prefer HT/quench of raw [semi-trimmed blank] stock... then forming while in the unstable 'W' temper... then natural aging to -T42 . Lots of good reasons for setting up fab sequence this way." Makes sense. Very interesting. Could technically do this with T3 I have in stock or does the 1x heat treat on Alclad rule mess it up?


Just FYI:
I sat down and unrolled the drawings and found a note section as follows:

"17S designation has been changed to 2024S. Next all the ribs are formed from 2024SO, then solution heat treated to the 2024ST6 condition at which time they gain strength and rigidity. Please note that immediately after quench the parts will be dead soft and warped. They must be straightened within an hour of quench.

 

[berkshire]

RoarkS (Mechanical)
Remember that 2024 is the most unforgiving as far as time goes of the heat treatable tempers, After heat treat it has to be kept in a freezer, and you only have about 10 minutes of usable working time before it hardens. The one hour time stamp on your spec is a bit optimistic. I used to be a hand straightener at one time, and found this out from bitter experience. Remember if you cannot get it straight in the W temper, it has to go back to heat treat, or get scrapped.
B.E.

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