ASTM A967-05

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: A 967 – 05
Standard Specification for
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Chemical Passivation Treatments for Stainless Steel Parts
This standard is issued under the fixed designation A 967; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope* health practices and determine the applicability of regulatory
limitations prior to use.
1.1 This specification covers several different types of
chemical passivation treatments for stainless steel parts. It
2. Referenced Documents
includes recommendations and precautions for descaling,
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2.1 ASTM Standards:
cleaning, and passivation of stainless steel parts. It includes
A 380 Practice for Cleaning, Descaling, and Depassivation
several alternative tests, with acceptance criteria, for confirma-
of Stainless Steel Parts, Equipment, and Systems
tion of effectiveness of such treatments for stainless steel parts.
B117 Practice for Operating Salt Spray (Fog) Apparatus
1.2 Practices for the mechanical and chemical treatments of
B 254 Practice for Preparation of and Electroplating on
stainless steel surfaces are discussed more thoroughly in
Stainless Steel
Practice A 380.
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2.2 Federal Specification:
1.3 Several alternative chemical treatments are defined for
QQ-P-35C Passivation Treatments for Corrosion-Resistant
passivation of stainless steel parts. Appendix X1 gives some
Steels
nonmandatory information and provides some general guide-
lines regarding the selection of passivation treatment appropri-
3. Terminology
ate to particular grades of stainless steel. It makes no recom-
3.1 Definition of Term Specific to This Standard—It is
mendations regarding the suitability of any grade, treatment, or
necessary to define which of the several commonly used
acceptance criteria for any particular application or class of
definitions of the term passivation will be used in this
applications.
specification. (See Discussion.)
1.4 Thetestsinthisspecificationareintendedtoconfirmthe
3.1.1 Discussion—Stainlesssteelsareautopassivatinginthe
effectiveness of passivation, particularly with regard to the
sense that the protective passive film is formed spontaneously
removal of free iron and other exogenous matter. These tests
on exposure to air or moisture. The presence of exogenous
include the following practices:
surface contamination, including dirt, grease, free iron from
1.4.1 Practice A—Water Immersion Test,
contact with steel tooling, and so forth, may interfere with the
1.4.2 Practice B—High Humidity Test,
formation of the passive film. The cleaning of these contami-
1.4.3 Practice C—Salt Spray Test,
nants from the stainless steel surface will facilitate the spon-
1.4.4 Practice D—Copper Sulfate Test,
taneous passivation by allowing the oxygen uniform access to
1.4.5 Practice E—Potassium Ferricyanide–NitricAcidTest,
the surface. The passive film may be augmented by chemical
and
treatments that provide an oxidizing environment for the
1.4.6 Practice F—Free Iron Test.
stainless steel surface.
1.5 The values stated in inch-pound units are to be regarded
3.1.1.1 In this specification, passivation, unless otherwise
as the standard. The SI units given in parentheses are for
specified, is defined as the chemical treatment of a stainless
information only.
steel with a mild oxidant, such as a nitric acid solution, for the
1.6 The following precautionary caveat pertains only to the
purpose of the removal of free iron or other foreign matter, but
test method portions, Sections 14 through 18 of this specifica-
which is generally not effective in removal of heat tint or oxide
tion: This standard does not purport to address all of the safety
scale on stainless steel. In the case of stainless steels with
concerns, if any, associated with its use. It is the responsibility
additions of sulfur for the purpose of improved machinability,
of the user of this standard to establish appropriate safety and
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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This specification is under the jurisdiction of ASTM Committee A01 on Steel, contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee Standards volume information, refer to the standard’s Document Summary page on
A01.14 on Methods of Corrosion Testing. the ASTM website.
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Current edition approved Sept. 1, 2005. Published September 2005. Originally Available from Superintendent of Documents, U.S. Government Printing
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approved in 1996. Last previous edition approved in 2001 as A 967 – 01 . Office, Washington, DC 20402.
*A Summary of Changes section appears at the
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