24ST Extrusions 3

[Merlin51]

I have an old 1940's vintage print for an extrusion that calls out the material as 24ST and Federal Spec QQ-A-354.

I was able to come across this x-ref for QQ-A-354:

"Aluminum Alloy -24ST Federal Spec. QQ-A-354, Navy Spec. 46A9," and "Specifications.- Federal QQ-A-354 Aluminum-alloy (AL-24) (aluminum-copper-magnesium (l.50%)-manganese); bars, rods, shapes, and wire."

However, it doesn't tell me much that I don't already know.

I have seen one (old) reference for 24ST extrusions as 2024-T4. I have also seen 24ST references to 2024-T4 (plate <0.250"), and 2024-T3 (sheet >0.249). I was recently told the the old T4 extrusion now is T3511.

According to an ASM handbook I have T4, T3, T351, T3510, and T3511 all have comparable corrosion and fabrication characteristics. I cannot find material properties on T4 extrusions.

FYI, the extrusion shape on the print has legs that are 0.062" thick.

I have checked MIL-HDBK-5, and didn't find anything in there.

Can anybody help me out here with a current x-ref for 24ST extrusions and QQ-A-354?

Thanks!

 

[der8110]

24ST is what is now known as 2024-T3. Current spec for 2024 extrusions is AMS-QQ-A-200/3.

You are right, there was a change in terminology for T4 temper. Not sure when, 1950's maybe. Today the difference is the aging process, natural or artificial. Since extrusions do change properties as they are extruded, to get a (modern) T4 or T42 temper you would have to extrude, anneal, then heat treat. Somewhat impractical since the T3, T3510, and T3511 temper extrusions already have optimum properties. So in other words, in today's scheme a T4 extrusion is mostly academic.

You might need to go back to ANC-5 (predecessor to MIL-HDBK-5) to find references to 24ST.

 

[rb1957]

would you be able to substitute an available T3511 extrusion for your intended purpose ?

i suspect that DERs would approve such a substitution.

 

[Merlin51]

Thanks for your information!

I was able to dig up a later version of the same print that calls the material out as a 2024-T4 extrusion, which helps.

I am looking at substituting T3511 for T4 with a DER approval. I'm just trying to put together the data to back up this decision.

Anyone know where I can find a copy of ANC-5?

 

[Merlin51]

I just downloaded a copy of ANC-5, and found properties for 24S-T4 Extrusions...PERFECT!

Thanks der8110 and rd1957!!!

 

[prost]

What about it Merlin51? How about letting us know where you got that downloaded copy of ANC-5?!!

 

[Merlin51]

After a bit of a search I was able to find ANC-5 "Strength of Metal Aircraft Elements" June 1951 Revision here:

http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA382434

Click the link next to this: "Handle / proxy Url :" And it will open up.

There you go!!!

 

[prost]

Give yourself a gold star, Merlin51, that ANC-5 link worked perfectly. Thanks!

 

[Merlin51]

Glad I could help!