ASTM A967 Testing Interpretation - No Customer Requirements

R

rsmoot

I'm looking for an interpretation on the ASTM A967 standard regarding "test requirements". I think one would need to read the actual text of the spec to be able to answer...

My question is " If a customer does not specify one of the 5 test methods (and efectively leaves it up to us), (putting on their purchase order only "Passivate per ASTM A967" Is testing actually "REQUIRED", or is it sufficient to say the item was passivated per that spec?

Now - I have to add - this is a technical question, not a question about what's right, or what the purchaser should be putting on the P.O.
Obviously, the right answer is to help the customer word the PO line correctly (for their needs) so they buy the right service, we document test appropriately, and validate it, etc.

I'd say this is a "theoretical question", but someone internally is actually proposing "not doing testing/validation" on the process, but still certifying it as done according to the spec.

Thanks for opinions.....
 

Ronen E

Problem Solver
Moderator
Hello,

http://www.astm.org/Standards/A967.htm

ASTM A967
Abstract

This specification covers several different types of chemical passivation treatments for stainless steel parts. The treatments are the following: immersion treatment using nitric acid solutions, immersion treatment using citric acid solution, and electrochemical treatment. Immediately after the removal from the passivating solution, the parts shall be thoroughly rinsed, using stagnant, countercurrent, or spray washes, singly or in combination, with or without a separate chemical treatment for neutralization of the passivation media. The chemical reactions of the passivating media on the surface of the stainless steel shall be stopped by rinsing of the stainless steel part, with or without a separate neutralization treatment. A chemical treatment shall be applied which will accelerate the formation of the passive film on a chemically clean stainless steel surface. The passivated parts shall exhibit a chemically clean surface and shall, on visual inspection, show no etching, pitting, or frosting. The following tests shall be performed on each lot of stainless steel parts: water immersion test, high humidity test, salt spray test, copper sulfate test, and potassium ferricyanide-nitric acid test. A free iron test shall be used for the detection of free iron on the surface of stainless steel.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This specification covers several different types of chemical passivation treatments for stainless steel parts. It includes recommendations and precautions for descaling, cleaning, and passivation of stainless steel parts. It includes several alternative tests, with acceptance criteria, for confirmation of effectiveness of such treatments for stainless steel parts.

1.2 Practices for the mechanical and chemical treatments of stainless steel surfaces are discussed more thoroughly in Practice A380.

1.3 Several alternative chemical treatments are defined for passivation of stainless steel parts. Appendix X1 gives some nonmandatory information and provides some general guidelines regarding the selection of passivation treatment appropriate to particular grades of stainless steel. It makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria for any particular application or class of applications.

1.4 The tests in this specification are intended to confirm the effectiveness of passivation, particularly with regard to the removal of free iron and other exogenous matter. These tests include the following practices:

(...)

I don't have the entire standard in front of me, but if a standard specifies both methods of achieving something and tests (whether voluntary or otherwise) for ascertaining that indeed this "something" was achieved, I think an unreserved declaration of "compliance with the standard" would be misleading if none of the tests were performed and/or acceptance criteria specified in the standard were not met. I think the right thing to do in such a case is to declare compliance with those sections of the standard that were followed and complied with.

Cheers,
Ronen.
 
R

Ray Kremer

Sorry for the late answer here.

The requirement was worded ambiguously for a while, the committee has fixed that now. The intention is indeed to require one of the test methods be used. If it is not specified by the customer then it is up to you to choose which one to use. A967, being a "Standard Specification" rather than a "Standard Practice", is officially geared towards passing a test rather than following a procedure.

Now, does this mean that everybody passivating per A967 actually does so? I very much doubt it.
 
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