ASTM A967-05e2
(Specification)Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts
Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts
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.
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:
1.4.1 Practice A—Water Immersion Test,
1.4.2 Practice B—High Humidity Test,
1.4.3 Practice C—Salt Spray Test,
1.4.4 Practice D—Copper Sulfate Test,
1.4.5 Practice E—Potassium Ferricyanide–Nitric Acid Test, and
1.4.6 Practice F—Free Iron Test.
1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.6 The following precautionary caveat pertains only to the test method portions, Sections 14 through 18 of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:A967 −05
StandardSpecification for
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Chemical Passivation Treatments for Stainless Steel Parts
This standard is issued under the fixed designation A967; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
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´ NOTE—Section 6.1.1.1 was editorially corrected in July 2007.
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´ NOTE—Section references were editorially corrected in Section 22.1 in March 2010.
1. Scope* 1.6 The following precautionary caveat pertains only to the
test method portions, Sections 14 through 18 of this specifica-
1.1 This specification covers several different types of
tion: This standard does not purport to address all of the safety
chemical passivation treatments for stainless steel parts. It
concerns, if any, associated with its use. It is the responsibility
includes recommendations and precautions for descaling,
of the user of this standard to establish appropriate safety and
cleaning, and passivation of stainless steel parts. It includes
health practices and determine the applicability of regulatory
several alternative tests, with acceptance criteria, for confirma-
limitations prior to use.
tion of effectiveness of such treatments for stainless steel parts.
1.2 Practices for the mechanical and chemical treatments of
2. Referenced Documents
stainless steel surfaces are discussed more thoroughly in
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2.1 ASTM Standards:
Practice A380.
A380 Practice for Cleaning, Descaling, and Passivation of
1.3 Several alternative chemical treatments are defined for
Stainless Steel Parts, Equipment, and Systems
passivation of stainless steel parts. Appendix X1 gives some
B117 Practice for Operating Salt Spray (Fog) Apparatus
nonmandatory information and provides some general guide-
B254 Practice for Preparation of and Electroplating on
lines regarding the selection of passivation treatment appropri-
Stainless Steel
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ate to particular grades of stainless steel. It makes no recom-
2.2 Federal Specification:
mendations regarding the suitability of any grade, treatment, or
QQ-P-35C Passivation Treatments for Corrosion-Resistant
acceptance criteria for any particular application or class of
Steels
applications.
3. Terminology
1.4 Thetestsinthisspecificationareintendedtoconfirmthe
3.1 Definition of Term Specific to This Standard—It is
effectiveness of passivation, particularly with regard to the
necessary to define which of the several commonly used
removal of free iron and other exogenous matter. These tests
definitions of the term passivation will be used in this
include the following practices:
specification. (See Discussion.)
1.4.1 Practice A—Water Immersion Test,
3.1.1 Discussion—Stainlesssteelsareautopassivatinginthe
1.4.2 Practice B—High Humidity Test,
sense that the protective passive film is formed spontaneously
1.4.3 Practice C—Salt Spray Test,
on exposure to air or moisture. The presence of exogenous
1.4.4 Practice D—Copper Sulfate Test,
surface contamination, including dirt, grease, free iron from
1.4.5 Practice E—Potassium Ferricyanide–NitricAcid Test,
contact with steel tooling, and so forth, may interfere with the
and
formation of the passive film. The cleaning of these contami-
1.4.6 Practice F—Free Iron Test.
nants from the stainless steel surface will facilitate the spon-
1.5 The values stated in inch-pound units are to be regarded
taneous passivation by allowing the oxygen uniform access to
as the standard. The SI units given in parentheses are for
the surface. The passive film may be augmented by chemical
information only.
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This specification is under the jurisdiction of ASTM Committee A01 on Steel, For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
A01.14 on Methods of Corrosion Testing. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2005. Published September 2005. Originally the ASTM website.
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approved in 1996. Last previous edition approved in 2001 as A967 – 01 . DOI: Available from Superintendent of Documents, U.S. Government Printing
10.1520/A0967-05E01. Office, Washington, DC 20402.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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A967−05
treatments that provide an oxidizing environment for the 4.2 Unles
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