AMS 2700: Which Type with Which Grade? 6

[Cryo1]

We picked up the SAE AMS 2700 specification here. I am wondering how to know which of the 8 types of passivation do I pick for a given grade of stainless?

 

[EdStainless]

Isn't there a table to tell you which are applicable?
There is in ASTM A380 and A967. The tables don't tell you what is the best, but they tell you what NOT to use.

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[Kenneth]

The alloy-specific passivation recommendations historically contained in the body of the text, and the extensive alloy listings in Table 2 of QQ-P-35 and AMS-QQ-P-35 have not been incorporated in AMS 2700. In my opinion, the existence of that guidance in the now-cancelled QQ-P-35 and AMS-QQ-P-35 specifications was a key factor in the typical structure of passivation requirement notes in aerospace applications, and was the reason why specific passivation "Type" or "Types" were not specified on more drawings which called out the QQ specifications.

As a result, we find ourselves in a situation where there are a large number of drawings calling out the cancelled QQ passivation specifications (without a type callout largely due to the guidance historically provided in the QQ specs) with a supersession notice that points to a replacement document (AMS 2700) that does not provide that guidance. In part due to the mess made by the SAE in the AMS-QQ-P-35 to AMS 2700 supersession, I (personally) favor explicit AMS 2700 callouts for aerospace parts that are consistent with guidance and recommendations for the specific material being passivated found in the tables in the QQ documents, such as:

"AMS 2700, Method 1, Type 6 or Type 7, Class 1" for UNS S0430, 302 and 305 materials.
"AMS 2700, Method 1, Type 2, Class 1" for UNS S30323 (303SE).
"AMS 2700, Method 1, Type 2 or Type 8, Class 1" for A-286.

Similarly certifying passivation to an "AMS 2700, Method 1, Type (insert type number here)" where either the cancelled QQ-P-35 or AMS-QQ-P-35 were/are called out would also appear wise. Where sample sizes rely on the default (QQ) sample size, and aren't modified by the part standard, procurement specification, etc., the certification should probably be appended with a Class 1 inspection callout (i.e. "AMS 2700, Method 1, Type (insert type number here), Class 1". The only potential difference is that for most lot sizes AMS 2700 reduces the number of samples required to be subjected to lot acceptance corrosion tests when compared to the earlier, superseded QQ-P-35 and AMS-QQ-P-35 default sample size requirements. But I would think one could (correctly) point to the cancellation/supersession notices of the QQ documents leading you to AMS 2700 and the fact that you had used the tightest and applicable (Class 1) sample size in the replacement specification.

Additionally: In any case where a vendor chose to use the AMS 2770, Type 1, either in the absence of a specific QQ Type callout on a part standard, or where an existing QQ-P-35, Type I callout had been explicitly invoked, the effect would be to "revert" to a process that was deliberately withdrawn and removed from QQ-P-35 in 1988.

Type I (a "Low Temperature" - 70° to 90° F nitric acid, sodium dichromate aqueous passivation solution) which was withdrawn and removed from QQ-P-35 in 1988 (with instructions to use alternate, specific types) has "reappeared" in AMS 2770 as Type 1. When Type I was withdrawn from QQ-P-35 (in the October 28, 1988 "C" revision) language was added to reference Table 2 in that document for selection guidance of appropriate alternate passivation treatments based on specific alloy type being passivated. This guidance, wording and table were carried forward into the superseding AMS-QQ-P-35 document when it was “transitioned” from the government document to the SAE AMS 2700 document.

That table and guidance is not contained in the AMS 2700 document (which the SAE has identified as superseding AMS-QQ-P-35 in it's February 2005 cancellation of AMS-QQ-P-35), nor is the QQ-P-35 / AMS-QQ-P-35 Type I callout included in the cross reference table included in the AMS-QQ-P-35 to AMS 2700 Type "Cross Reference" Table found on the first page of the cancelled AMS-QQ-P-35A specification. The QQ to AMS type "cross reference" on page one of the cancelled AMS-QQ-P-35A does not include/cover the QQ Type I. In the absence of the instructions provided in the cancelled QQ documents, and with no coverage of QQ Type I in the cross reference provided in AMS-QQ-P-35A (itself buried in the body of the document as opposed to a separate super session notice), it is reasonable to expect that some suppliers/processors will follow the one-for-one pattern established in the cross reference and use AMS 2770 Type 1 where QQ-P-35 Type I is specified, or alternately to use Type I where no specific type were specified.

AMS 2700 also added a "Method 2" (Citric Acid based) solution in addition to the Nitric Acid based (Method 1) solutions found in the QQ documents. Per AMS 2700: "Where no type is specified, the processor may use any of the listed types that meet the requirements given herein, unless citric acid passivation in accordance with Method 2 is acceptable to purchaser." Note that all the "types" identified in AMS 2700 are nitric acid (Method 1) solutions. In other words, using a citric acid based (Method 2) passivation where not specifically called out as Method 2 on the drawing requires "purchaser acceptance". I don't have to tell anybody who manufactures (or stocks) "standard" parts for multiple aerospace purchasers they would have a fun time managing or implementing that if they chose to use the "new" citric acid passivation solutions.

Class: The cancelled "aerospace" QQ passivation documents superseded by AMS 2700 had a single inspection level. AMS 2700 introduces additional, significantly-reduced sample sizes for many parts which are processed to this specification. While a Class 1 (sample size) callout is identified in AMS 2700 for "fasteners," to remove the potential for misinterpretation, or the failure of a processor to properly identify parts being processed as "fastener" hardware (by either manufacturers or outside processors), it is highly desirable to explicitly cite the appropriate inspection level (Class 1) directly on the part standard passivation callout for fastener hardware. Note: Even assuming the "proper" Class 1 inspection levels are used, for most lot sizes AMS 2700 reduces the number of samples required to be subjected to lot acceptance corrosion tests when compared to the earlier, superseded QQ-P-35 and AMS-QQ-P-35 requirements.

 

[EdStainless]

Have you looked at A967?
It is intended to be the replacement for P-35.
The notes and tables are all there.

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Rust never sleeps
Neither should your protection

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[Kenneth]

Despite the mess (detailed above) that's been made with AMS 2700, where the cancelled and superseded QQ-P-35 or AMS-QQ-P-35 documents have been called out, there is no supersession trail (no "authority") to use ASTM A967 in their place for aerospace applications.

From the QQ-P-35 cancellation notice (

http://assist.daps.dla.mil/docimages/0001/26/21/qqp35.pd1):

"Future acquisitions for this product should refer to American Society for Testing and Materials (ASTM)
Specification ASTM A967, “Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts”, or, SAE Aerospace Materials Specification (AMS) AMS-QQ-P-35, “Passivation treatments for Corrosion-Resistant Steel”. Aerospace applications require the use of AMS-QQ-P-35."

Where AMS-QQ-P-35 is called out (or you got to it by following the QQ-P-35 cancellation/supersession notice for your "aerospace application") the only authorized replacement is AMS 2700, regardless of whether your application is an aerospace one or not. From the AMS-QQ-P-35 Cancellation notice:

"This specification has been declared “CANCELLED” by the Aerospace Materials Division, SAE, as of February, 2005, and has been superseded by AMS 2700. The requirements of the latest issue of AMS 2700 shall be fulfilled whenever reference is made to the cancelled AMS-QQ-P-35, utilizing the “Type” designation noted in the following table. By this action, AMS-QQ-P-35 will remain listed in the Numerical Section of the Index of Aerospace Material Specifications, noting that it has been superseded by AMS 2700."

 

[EdStainless]

The word in there is "or". If you are working to a DoD requirement you are allowed to switch to either of the referenced specs.

This (the link) is a revised cancellation notice.
Don't ask how you revise cancelled specifications.

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Rust never sleeps
Neither should your protection

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[Kenneth]

Respectfully no, go back and look again. I stand by my statement that "where the cancelled and superseded QQ-P-35 or AMS-QQ-P-35 documents have been called out, there is no supersession trail (no "authority") to use ASTM A967 in their place for aerospace applications."

You stopped reading at the "or" in the QQ-P-35 cancellation notice and ignored the further "Aerospace applications require the use of AMS-QQ-P-35" in the very next sentence.

As further noted, the AMS-QQ-P-35 cancellation notice solely cites AMS 2700 (and not A967) as the superseding document.

Regarding the QQ-P-35 cancellation notice. My experience is the government can (and will) do whatever the heck it wants to:

QQ-P-35C was cancelled on April 4, 1997 (Notice 1).

It was "reinstated" on November 14, 1997 (Notice 2, Superseding Notice 1):

"QQ-P-35C, dated 28 October 1988, is hereby reinstated and may be used for acquisition UNTIL 3 July 1998 at which time it will be cancelled. The Defense Industrial Supply Center (IS) herby assumes preparing activity responsibility
in lieu of the Defense Supply Center Richmond (GS)."

And finally, again cancelled on Septemeber 11, 1998 (Notice 3, superseding Notce 2) with the most recent (final?) cancellation notice shown at the link provided above (

http://assist.daps.dla.mil/docimages/0001/26/21/qqp35.pd1)...

 

[Cryo1]

Guys, thanks for the information. My interest is simply knowing how to know when to assign a SAE AMS 2700, Method 1, Type x to a grade of CRES y. We have 2700 but not 967. Are the types listed in the two different specs identical?

 

[Kenneth]

My suggestion:

Look at the Table II (starts on page 8) of the cancelled QQ-P-35C (I'd point you to AMS-QQ-P-35, but unlike AMS-QQ-P-35, QQ-P-35C is available for free at

http://assist.daps.dla.mil/docimages/0000/32/98/50793.pd5,

and the tables are the same in both documents) to see if you can find your specifiic alloy listed along with the corresponding reccomended passivation type. With that roman numeral type reccomendation from QQ-P-35 in hand, you can make a corresponding AMS 2700 (Method 1) callout by changing the roman numberal to the corresponding arabic numneral as shown below:



QQ-P-35, Type II: AMS 2700, Method 1, Type 2
QQ-P-35, Type VI: AMS 2700, Method 1, Type 6
QQ-P-35, Type VII: AMS 2700, Method 1, Type 7
QQ-P-35, Type VIII: AMS 2700, Method 1, Type 8

The above listed types are the same. Remember to include the "Class" (sample size) callout if it's importent to you.

 

[Cryo1]

Thanks Kenneth. We have both specs in house. The question is Type 1, 3, 4, and 5 which were previously withdrawn but now appear again in the newest AMS 2700 spec. Why did these types comeback and what metals do we associate with these metal types?

 

[Temporis]

Kenneth you posted this.

------------
Despite the mess (detailed above) that's been made with AMS 2700, where the cancelled and superseded QQ-P-35 or AMS-QQ-P-35 documents have been called out, there is no supersession trail (no "authority") to use ASTM A967 in their place for aerospace applications.

From the QQ-P-35 cancellation notice (

http://assist.daps.dla.mil/docimages/0001/26/21/qqp35.pd1):

"Future acquisitions for this product should refer to American Society for Testing and Materials (ASTM)
Specification ASTM A967, “Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts”, or, SAE Aerospace Materials Specification (AMS) AMS-QQ-P-35, “Passivation treatments for Corrosion-Resistant Steel”. Aerospace applications require the use of AMS-QQ-P-35."

Where AMS-QQ-P-35 is called out (or you got to it by following the QQ-P-35 cancellation/supersession notice for your "aerospace application") the only authorized replacement is AMS 2700, regardless of whether your application is an aerospace one or not. From the AMS-QQ-P-35 Cancellation notice:

"This specification has been declared “CANCELLED” by the Aerospace Materials Division, SAE, as of February, 2005, and has been superseded by AMS 2700. The requirements of the latest issue of AMS 2700 shall be fulfilled whenever reference is made to the cancelled AMS-QQ-P-35, utilizing the “Type” designation noted in the following table. By this action, AMS-QQ-P-35 will remain listed in the Numerical Section of the Index of Aerospace Material Specifications, noting that it has been superseded by AMS 2700."

------------------

Can you send me to an official link that states exactly what you said above... The one link that you did post above only states that QQ-P-35 is superseded by ASTM A967.

I need something official that tells me AMS 2700 is superseding QQ-P-35 or QQ-P-35C. Thank you sir!

 

[Kenneth]

The link that I provided (and that you copied in your message) is the current, official government cancellation notice for QQ-P-35C (the "last," most "recent" revision of QQ-P-35).

Future acquisitions for this product should refer to American Society for Testing and Materials (ASTM) Specification ASTM A967, “Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts”, or, SAE Aerospace Materials Specification (AMS) AMS-QQ-P-35, “Passivation treatments for Corrosion-Resistant Steel”. Aerospace applications require the use of AMS-QQ-P-35.

(my emphasis) and is extracted directly from the document at that link.


The SAE AMS-QQ-P-35 cancellation notice:

This specification has been declared “CANCELLED” by the Aerospace Materials Division, SAE, as of February, 2005, and has been superseded by AMS 2700. The requirements of the latest issue of AMS 2700 shall be fulfilled whenever reference is made to the cancelled AMS-QQ-P-35, utilizing the “Type” designation noted in the following table. By this action, AMS-QQ-P-35 will remain listed in the Numerical Section of the Index of Aerospace Material Specifications, noting that it has been superseded by AMS 2700.

is part of the copyrighted "A" revision of that document, that goes on to say:

Cancelled specifications are available from SAE.

that is available (for a fee) from

http://www.sae.org/servlets/productDetail?PROD_TYP=STD&PROD_CD=AMSQQP35A

Gotta love a business model that requires you to buy a cancelled document just to get your hands on the official cancellation/supersession notice for that document (that then directs you to go purchase yet another one of their documents)...

If anything less than the "official" AMS-QQ-P-35 cancellation notice will meet your needs (i.e. you don't want to shell out $59 for a cancelled document to get your hands on the cancellation/supersession notice for that document) and you can take IHS's word on this, take a look at

http://global.ihs.com/doc_detail.cf...nput_doc_number=ams-qq-p-35&input_doc_title=.