Has AMS-QQ-P-35 Been Superseded by AMS 2700?
September 23, 2010
Q. Which is Which?! Has AMS-QQ-P-35 [link is to spec at TechStreet] been superseded by AMS2700 [link is to spec at TechStreet]? I have mil-spec hardware that calls out for passivation per AMS-QQ-P-35, Type 6 or 7. The test reports from my supplier reflect the passivation was performed per AMS2700B(AMS-QQ-35)Method-1-, Type-2- Do I have a problem here? And where can I obtain objective evidence to back it up?John Clausen
Defense Contractor - Anniston, Alabama, USA
October 21, 2010
A. Mil spec QQ-P-35 for stainless steel passivation was replaced by both
ASTM A967 [link is to spec at TechStreet]
and AMS QQ-P-35 (the latter for aerospace applications). The notice for this is available from https://assist.daps.dla.mil/quicksearch/
AMS QQ-P-35 was really just a temporary measure, a direct carryover of the mil QQ-P-35, to give SAE more time to prepare their replacement, which is AMS 2700. SAE's own website will tell you this: http://standards.sae.org/amsqqp35a
I've also got a scanned copy of the AMS QQ-P-35 cancellation notice from 2005 on the web at: http://www.citrisurf.com/amsqqp35_cancel.pdf
AMS 2700 Method 1 is the nitric baths, essentially unchanged from QQ-P-35. Type 2 is fine for any grade that type 6 or 7 would be used on.
Stellar Solutions, Inc.
November 11, 2010
A. QQ-P-35 was superseded by AMS-QQ-P-35 for aerospace products and AMS-QQ-P-35 was cancelled and superseded by AMS2700. AMS2700 has a class 4 which is supposed to be used when QQ-P-35 or AMS-QQ-P-35 are specified. The difference is sample size for verification testing. You need to talk to your customer. Some customers require certifications to old specs even if they have been cancelled.
There can be a problem with using Type 2 when type 6 or 7 is required. All of the different types will yield satisfactory results with sufficient cleaning, passivation, and verification. The problem is that you will not have provided what the customer required. It can be argued that it is demonstrable that the parts have been passivated but that may not be good enough especially when types 6 and 7 are straight nitric acid at different concentrations and temperatures. Type 2, however, is nitric acid with sodium dichromate at a moderate temperature. Hope this helps.
- Torrance, California, USA
May 23, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. I am a mechanical engineer working at a company that manufactures ordnance devices for military usage.
We have a part constructed from 304 SST, and our manufacturing procedure calls out for a Type II solution. I did some research, and found that we really should be using a Type VI or VII solution.
We are in the middle of dealing with our customer reviewing in detail all of our manufacturing steps for this product. The parts have already been made, but they were passivated using the Type II solution.
Is this an issue that I need to bring to their attention as a potential problem, or does the Type II work just as well as VI or VII? Can the sodium dichromate damage the 304 SST in any way?
If there is not a problem, then why would there be a separate callout depending on whether you are passivating 303 vs 304 SST?
- Hollister, CA USA
^- Privately contact this inquirer -^
May 23, 2013
A. Hi Jamie. We found a thread which appears to answer your question, and appended your inquiry to it. If I am misreading your question and you feel it is not answered, or you wish to follow up, get back to us. Thanks.
Ted Mooney, P.E. RET
Brick, New Jersey
June 10, 2013
Given the notation you're using I assume you are still working off QQ-P-35. It's true that the process table in that document assigns 304 to Types VI and VII only. However, if the parts came out of the Type II bath with an acceptable appearance and there were no other difficulties, then they should be fine to use.
Stellar Solutions, Inc.