The authoritative public forum
  for Metal Finishing since 1989
-----

Differences between QQ-A-250/4 and QQ-A-225/6

To Whom It May Concern

I would like to know what the differences is between QQ-A-250/4 and QQ-A-225/6.

The material I received from a supplier is certified to being Alloy 2024 Temper T351 that indicates the material was melted and manufactured in the U.S.A. meeting the requirements of T4 temper and QQ-A-225/6.

I'm required to use the QQ-A-250/4.

Thank you.

Brandie L. Gerou
manufacturing - Grand Rapids, Michigan
2004

---

Brandie, you're going to need to chat with your customer. The QQ-A-225 series of specifications are for rolled bar, while the AMSQQA250 group are for sheet and plate. Depending on the size, the mechanical properties guaranteed by the manufacturer can be slightly different, and the tests that are done are also different. Think about it- both specs have a bend test. Is bending a rod the same as bending a sheet? Nope: hence they have different acceptance criteria for that test.
That said, material per the two specs is usually interchangeable. We do it all the time, and our drawings are structured to allow just that substitution.
I'm sure it makes sense to you that flats and rectangular stock are going to be easier to find as QQ-A-250 material, while round stock will be readily available as QQ-A-225 (or QQ-A-200, extrusions).
If your customer's drawing or PO says you must use QQ-A-250, then whether you need to or merely should get approval to use the QQ-A-225 material depends on your contracts. This is the sort of thing I do all the time for our vendors, so it's not necessarily a big deal. The most difficult part is usually finding someone willing to make a decision. Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York
2004

What is the designation for 250/4 or /6 or /11, what does that number stand for?

francis Gilman
Supervisor - Ft Lauderdale, Florida
November 11, 2010

---

Hi, Francis. These specs are cancelled.

But /4 referred to type 2024 plate and sheet, /6 referred to type 5083, and /11 referred to type 6061.

All been replaced by AMSQQA250 general specifications for aluminum plates & sheets and related detail specifications for aerospace parts, and ASTM B209 for non-aerospace parts. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 11, 2010