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ASTM A967 vs. AMS 2700? Which is the right passivation spec?

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Q. Did ASTM A380 [affil. link] go away, and ASTM A967 [affil. link] replace it?

My customer wants to put A380 on his print for standard passivation, but my plater tells me that he passivates to A967. What should I tell my customer?

2nd question, if I ask for standard passivation on imported product, what ASTM spec do you think I will get?

Thank you

Gene Prehatney
- Champlin, Minnesota

A. First question: The current ASTM versions are A380 "Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems" and A967 "Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts".

It is relatively easy to modify a passivation process to satisfy ASTM A380 [affil. link] , and ASTM A967 [affil. link] , and QQ-P-35C [link is to free spec at Defense Logistics Agency, dla.mil] and AMS2700 [affil. link] (primarily, a little paperwork). Have the plater do so, and then certify to multiple standards. (Lee Kremer has pointed out that A380 is not a Specification, only a Practice).

Second question: A guessing game? "Standard passivation" is meaningless unless the standard is specified.

Ken Vlach [deceased]
- Goleta, California

contributor of the year Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.

A. As Ken says, ASTM A380 [affil. link] should not be used as a passivation specification, and QQ-P-35 has been canceled. The 3 consensus specifications used at this time, and that should be used for all specifications of passivation are:

ASTM F86 [affil. link] for Orthopedic implants,
AMS2700 [affil. link]for Aerospace,
ASTM A967 [affil. link] for all other applications.
There are other in-house specifications for some companies.

A-380 has a lot of excellent recommendations on general cleaning etc. of stainless steel, but should never be used as a passivation spec.

AMSQQP35 [canceled, affil. link] is being canceled in favor of AMS2700 [affil. link] (at the moment it is version B)

You should never ask for "standard passivation" on imports. Always specify exactly what you want-- e.g., ASTM A967 [affil. link] 01e, Citric 4 or AMS2700 [affil. link] B Nitric 1. If you do not specify, they can use whatever they want, even ways that are not in any of the specifications! What is standard to you may not be standard to them.

lee kremer
lee kremer sig
Lee Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
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Q. I am struggling to understand which spec to use for passivation. Is there any clear direction or is it optional? Thanks for reading.

John Wilt
Engineer - Cambridge, Massachusetts
December 17, 2008


A. The "right" spec is the one that your customer requires. ASTM A967 [affil. link] is certainly more lax regarding passivation verification testing, which can be a good thing or a bad thing. AMS2700 [affil. link] requires both solution and per-lot corrosion resistance testing.

Since you're considering an AMS spec, I assume you have aerospace customers. If not, I would stick with ASTM.

Terry Lycans
Aerospace - Dayton, Ohio, USA

A. One of the differences is in the definition of 'a lot' for testing purposes. ASTM A967 [affil. link] uses the same definition as did the old Federal Specification, QQ-P-35.html, which allowed one to consider all production of similar material done in 24 hours to be a single lot. AMS2700 [affil. link] considers different parts, or the same part made at different times, to be different lots (with the exception for parts with the legacy QQ-P-35 called out, when you can use the older definition.) You can guess the increase in the amount of testing involved.

There are other differences- ASTM A967 [affil. link] allows the use of any mix of nitric and water, so long as you show it works (Nitric 5 solution). The ASTM doesn't default to the nitric acid formulations, as AMS2700 [affil. link] does. AMS2700 [affil. link] has an iron concentration maximum, absent from ASTM A967 [affil. link] . AMS2700 [affil. link] exempts 440C from testing. And there are other differences.

We design our own parts, and do our own passivation in house, and hence prefer the testing requirements of ASTM A967 [affil. link] . If you're having it done for you, the testing is someone else's problem, so you might consider AMS2700 [affil. link].

lee gearhart
Lee Gearhart
metallurgist - E. Aurora, New York

thumbs up signTerry/Lee, Thanks for your responses. They were helpful.

John Wilt [returning]
- Cambridge, Massachusetts
January 20, 2009

Q. Can you please tell me the differences between the passivation processes AMS2700 [affil. link]C vs ASTM A967 [affil. link] . I have a note requirement for the ASTM A967 [affil. link] , Type 6 or 7 requirement on some parts and the parts were passivated to the AMS2700 [affil. link] C, Method 1, Type 6 requirement.

Ted Nance
customer - San Diego, California
October 21, 2009

A. The two standards are essentially equivalent. Both contain a carryover of QQ-P-35C with the addition of the more recently developed citric acid based process. The AMS standard is used by the aerospace industry while the ASTM standard is used by generally everyone else.

QQ-P-35B contained six nitric acid bath Types. The C revision removed four of those and added two, leaving as options, Types II, VI, VII, and VIII. A967 renumbers those to 1 through 4 (there is no such thing as A967 Type 6 or 7) while 2700 restores the missing four for a total of eight Types.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
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McHenry, Illinois
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AMS2700 [affil. link] vs. AMSQQP35 [canceled, affil. link]

Q. Explain the difference between passivation specs AMS2700 [affil. link] and AMSQQP35 [canceled, affil. link]

Dan Mason
- San Jose, California, USA
March 22, 2013

A. Hi Dan. There is no AMSQQP35 [canceled, affil. link] anymore. It was cancelled in early 2003 in favor of AMS2700 [affil. link].


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

Q. What are the differences in the passivation specs AMS2700 [affil. link] and ASTM A967 [affil. link] ?

Bill Pinzon
- Greenlawn, New York, US
November 23, 2013

A. Hi Bill. As you see, we added your question to a thread which already answers it. Good luck.


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

Q. I was looking at this thread and had this question...

What are the differences between the ASTM F86 [affil. link] -13 spec and the ASTM A967 [affil. link] spec? Is one better than another for medical devices?

Justin Jones
- St. Paul, Minnesota, USA
February 22, 2017

A. Hi Justin. It seems to me that ASTM F-86 is only for orthopedic implants.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. A967 is a standard covering treatments to passivate stainless steel (regardless of what it will be used for) and then test methods to show that it was passivated.

F86 refers to surgical implants of any metallic alloy, and basically just says "do whatever treatment is applicable and appropriate to ensure corrosion resistance".

And then there's ASTM F1089 [affil. link] , which is test methods to show stainless steel surgical instruments have been passivated.

As far as the stainless steel passivation process itself, you're pretty much always going to work your way back to A967. But if it's a medical instrument or implant, then you're also going to have to show the appropriate tribute to an F standard.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
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McHenry, Illinois
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Q. I have an engineering drawing that calls out passivation IAW AMS2700 [affil. link], Method 2, Type 2. In reading through the specification I believe the drawing is incorrect. It appears that the types are associated with method 1, not method 2. Is this correct?

Tom Blauser
- Dayton, Ohio, USA
February 28, 2017

A. Tom,
Correct. Method 1 is subdivided into 8 Types (corresponding to the types in old QQ-P-35) while Method 2 is not subdivided.

So the question is, did they mean "Method 1 Type 2" or "Method 2 OR Method 1 Type 2"

ray kremer
Ray Kremer
Stellar Solutions, Inc.
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McHenry, Illinois
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Q. Hello,

I qualified my internal passivation process following Citric 2 Method in ASTM A967 [affil. link] which has the following requirements:
Concentration: 4 to 10 weight percent of citric acid.
Temperature 120 °F to 140 °F
Time: 10 minutes

I set my process parameters as indicated below
Concentration: 8 weight percent of citric acid
Temperature: 120 to 140
Time: 17.5 minutes ± 2.5 minutes

I ran my validation at the nominal settings (8, 130 °F and 17.5 min) and the auditor is asking me why we did not run the validation in the process limits. I replied that the parameters are in compliance with standard A967 but he's telling that we don't have objective evidence to support the validation since A967 defines minimum requirements that could be insufficient to my process. In simple terms, he's saying that given 2 SS surfaces which have different concentrations of free iron, the chemical reaction will take longer in the surface with more free iron. That makes sense.
Based on the previous information, the concern is regarding the minimum requirements in A967. Do the parameters in A967 cover any worst case scenario? If so, how could I support that statement? I assume that A967 was developed running several extreme conditions but I've been looking for that information and couldn't find anything about it.
I really appreciate your collaboration.

Juan Brizuela
- San Jose, Costa Rica
April 4, 2017

A. Juan,
If you process parts within the parameter ranges given by ASTM A967 [affil. link] , and one part per lot passes one of the listed test methods, then all you can say is you ran the parts in accordance with A967.

Determining the suitability of A967 for your specific parts is up to you, or requirements set by your customer. I.e., in some cases the best minimum time for your process may be longer than A967's stated minimum time. Some customers ask for the parts to pass salt spray testing longer than A967's required 2 hours, etc.

"Validation" as a term is not defined or used in A967 and means several different things depending on who you talk to. The best thing do to is ask the customer what they expect.

This auditor you are dealing with, what organization is he with? Your customer? What requirement or standard is he auditing you against, since clearly it is not A967?

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
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Q. Hello,

While carrying out passivation tests we came across the following apparent contrast.
Are certain nitric acid passivation processes in AMS2700 [affil. link] and ASTM A967 [affil. link] indeed equivalent, e.g AMS2700 [affil. link] type 7 and ASTM A967 [affil. link] Nitric 3 ?
AMS2700 [affil. link] specifies nitric acid concentrations as percentage of volume of a 42° Baumé solution, i.e., of a solution of about 67 wt.% nitric acid.
However ASTM A967 [affil. link] specifies nitric acid concentrations as volume percent. To me this means volume percent of pure nitric acid, resulting in significantly stronger passivation solutions than AMS2700 [affil. link]. Is this correct?

Jan Mulder
- Hengelo, Overijssel, Netherlands
July 4, 2017

A. Jan,
Both standards are based heavily on the old QQ-P-35.

Revision C of QQ-P-35 had some of the formulas taken out, so it had only types II, VI, VII, and VIII. ASTM A967 [affil. link] renumbered those to nitric 1 through 4, while AMS2700 [affil. link] brought back the ones that had been removed and has types 1 through 8.

Both standards express the formulas as volume percent of nitric acid, though only 2700 actually mentions the nitric stock solution is 42 °Baumé/67 wt%. This is actually an oversight of A967 that will be corrected in the next revision.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
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thumbs up sign Ray,

Thank you for answering.
Indeed also my conclusion is that it is an omission.
In the ASTM A967 [affil. link] and the nitric acid concentrations mentioned must be percentage by volume of a reagent of 67 wt.% nitric acid.

Jan Mulder [returning]
- Hengelo, Overijssel, The netherlands

Q. My question & my situation: Difference between ASTM F86 [affil. link] and ASTM A967 [affil. link] Passivation?
All The specifications are the same, then why are the Names different?

Shrinivas Jadhav
Mechanical Engineering - penang, Malaysia
May 31, 2018

A. Hi Shrinivas. We appended your question to a thread which should clearly answer it for you: ASTM F86 is "Standard Practice for Surface Preparation and Marking of Metallic Surgical Implants" -- but get back to us if you are still confused.

But again, please describe your situation. Is your business surgical implants, or are you with a passivation shop, or what? Thanks.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Q. In reading ASTM A967 [affil. link] and AMS2700 [affil. link] it seems that there is quite a bit of overlap but with differences in the bath variables or verification requirements. Is this a correct assessment?

Also, how common is it for a purchaser of a good to specify a specific passivation type in a standard rather than reference the entire standard and leave the type selection up to the manufacturer? If the part passes the verification test, what differences in function can occur in the part's use if differing acid baths are used? Especially in the fastener industry I have seen it is difficult to source a specific product according to a specific type within these standards.

Thanks for your time.

Chris Hauser
- Orlando, Florida, USA
November 2, 2018

Q. Hi Sir,
We have ambiguity in interpreting the specification requirement for testing on passivated CRES. Need your technical support to clarify whether our interpretation is correct and meeting the specification requirement.

PFB details of our interpretation against specification.

AMS2700 [affil. link] F:- Passivation of Corrosion Resistant Steels -- AMS2700 [affil. link]
Paragraph ref.. Specification description Testing requirement For Austenitic steels of the AISI 200 or AISI 300 series. Copper Sulphate.
For precipitation hardened steels. Copper Sulphate.
Ferritic steels containing more than 16% chromium. Copper Sulphate.

ASTM A967 [affil. link] :- Chemical Passivation Treatments for Stainless Steel Parts -- ASTM A967 [affil. link]
Paragraph ref.. Specification description Testing requirement
14.4.1 Austenitic stainless steels in the 200 and
300 series. Copper Sulphate.
Duplex stainless steels. Copper Sulphate.
Precipitation hardened stainless steels Copper Sulphate.
Ferritic 400 series stainless steels having a
minimum of 16 % chromium. Copper Sulphate.

August 20, 2019

A. Prajan,
You have that correct, so I'm not sure why you are confused. The text for that in both standards was copied almost directly from the old MIL-STD-753. A967 later added duplex and precipitation hardening grades, which were not mentioned as either "recommended" nor "not recommended" in the original MIL 753.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
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Q. I am new to the passivation field and trying to determine the best method to process different parts when the only specification I have on my orders is QQ-P-35 or QQ-P-35C. I know both have been replaced by AMS2700 [affil. link] and ASTM967. 1. How do you determine which new specification to use and 2. Should I use the nitric method for the different stainless steels as described in QQ-P-35 or can I use the more environmentally safer appropriate citric acid methods?

Andrea Bourdelais
manufacturing - Huntington, West Virginia, USA
October 3, 2019

A. Andrea,
AMS2700 [affil. link] is intended for use in the aerospace industry, while everybody else pretty much goes with ASTM A967 [affil. link] .

In general with the new standards you should be able to switch over to citric acid, but that does still depend on what's stated on the part drawing/purchase order/etc. and what your customer agrees to accept.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner

thumbs up sign  Thank You for your response.

andrea Bourdelais [returning]
BEK Engineering - Huntington, West Virginia, USA

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