Allowables for 7075-T6 per WW-T-700/7

[BVF]

Does anyone know of published A-basis allowables for 7075-T6 per WW-T-700/7 ? This material is not listed in the AR-MMPDS-01 (MIL-HDBK-5J).

A vendor has made parts from the above material instead of 7075-T6511 per QQ-A-200/11 as required. Because of lead time issues, we have been asked to approve the alternate material. I have only been able to obtain the mill's certification sheet which doesn't rise to the level of A-basis.

Brent

 

[40818]

You can only approve the parts material if you know its properties, though commercial pressures somtimes try to get you to do so.
what form is the material?? the WW spec is a drawn tubing if im correct.
Do you have "S" basis from the vendor?

 

[BVF]

Thanks, 40818. This material is rectangular drawn tubing, as you said.

I have material properties in a generic handbook, but they are not labeled A- or B- or even S-basis.

My understanding of FAR 25.613 is that I need A-basis allowables, or that I have to conduct testing to ascertain the allowables for my "premium selection", which I don't want to do because of time constraints. I'm told by the material supplier that this material is a better material than is required by our drawing.

I did contact the people who compile and publish the MMPDS, and I was told that there is no table for this material in MMPDS-03, which I don't have.

Brent

 

[40818]

I found this in the McDonnell Douglas Design Manual, it gives values for the base 7075-T62 WW-T-700/7.

Tried and failed to upload the snapshot with the data, let me know your email address and i will send the sheet to you. You might need to ROT13 your address becasue eng-tips dont like them appearing un-scambled.

E=10.4e6
Ftu = 77KSI
Fty = 66KSI

Care with T6 materials needs to be taken as they are susceptable to stress corrosion cracking. Will continue to look in other sources.

 

[BVF]

40818: I would appreciate that very much. Thank you.

ori@cnk2pnetb.pbz
(ROT13)

My application is not fatigue critical, so stress corrosion cracking is not a concern.

Thanks.

Brent

 

[40818]

Done.