ASTM B940-05(2014)
(Practice)Standard Practice for Testing Non-Chromate Coatings on Zinc and Cadmium Surfaces
Standard Practice for Testing Non-Chromate Coatings on Zinc and Cadmium Surfaces
SIGNIFICANCE AND USE
4.1 This practice is applicable to non-chromate coatings that are colorless, colored, electrochemically applied or non-electrochemically applied. The zinc or cadmium, or both, may be electrodeposited, mechanically deposited, hot-dipped, rolled, or in the form of castings.
4.2 Because of variables inherent in the salt-spray test which may differ from one test cabinet to another, interpretation of test results for compliance with expected performance should be specified by the purchaser.
4.3 Properties such as thickness, color, luster, and ability to provide good paint adhesion are not covered in this practice, nor are the chemical composition and the method of application of these finishes.
SCOPE
1.1 This practice covers a procedure for evaluating the protective value of chemical and electrochemical conversion coatings produced by non-chromate (chromate being defined as a compound that has chromium in the plus six oxidation state, and as such, chromium compounds in other oxidation states, such as plus three, shall not be excluded) treatments of zinc and cadmium surfaces.
1.2 The protective value of a non-chromate coating is usually determined by salt-spray test and by determining whether or not the coating possesses adequate abrasion resistance when applied for that purpose.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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: B940 − 05 (Reapproved 2014)
Standard Practice for
Testing Non-Chromate Coatings on Zinc and Cadmium
1
Surfaces
This standard is issued under the fixed designation B940; 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.
1. Scope products visible to the unaided eye at normal reading distance,
except that the presence of white corrosion products at sharp
1.1 This practice covers a procedure for evaluating the
edges (for example, on threaded fasteners) and at junctions
protective value of chemical and electrochemical conversion
between dissimilar metals should not be considered failure. In
coatingsproducedbynon-chromate(chromatebeingdefinedas
some instances, it may be desirable to regard the first appear-
a compound that has chromium in the plus six oxidation state,
ance of red rust as failure.
and as such, chromium compounds in other oxidation states,
3.1.2 significant surfaces—in general, significant surfaces
suchasplusthree,shallnotbeexcluded)treatmentsofzincand
are those surfaces that are visible and subject to corrosion or
cadmium surfaces.
wear, or both, except that surfaces that are normally difficult to
1.2 The protective value of a non-chromate coating is
coat by electroplating or mechanical deposition may be ex-
usually determined by salt-spray test and by determining
empt. The designation of significant surfaces may be indicated
whether or not the coating possesses adequate abrasion resis-
on the drawing.
tance when applied for that purpose.
4. Significance and Use
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4.1 This practice is applicable to non-chromate coatings that
standard.
are colorless, colored, electrochemically applied or non-
electrochemically applied. The zinc or cadmium, or both, may
1.4 This standard does not purport to address all of the
be electrodeposited, mechanically deposited, hot-dipped,
safety concerns, if any, associated with its use. It is the
rolled, or in the form of castings.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.2 Because of variables inherent in the salt-spray test
bility of regulatory limitations prior to use.
which may differ from one test cabinet to another, interpreta-
tion of test results for compliance with expected performance
2. Referenced Documents
should be specified by the purchaser.
2
2.1 ASTM Standards:
4.3 Properties such as thickness, color, luster, and ability to
B117 Practice for Operating Salt Spray (Fog) Apparatus
provide good paint adhesion are not covered in this practice,
nor are the chemical composition and the method of applica-
3. Terminology
tion of these finishes.
3.1 Descriptions of Terms:
3.1.1 time to failure—time to failure will depend on the type 5. Conditioning
of coating tested. The minimum expected protective value
5.1 Aging—Before subjecting a non-chromate coating to
obtainable in a given salt spray test is given in Appendix X2.
test, check with the chemical producer to determine if aging is
3.1.1.1 Discussion—In most instances, failure is defined as
an issue that needs to be considered.
the first appearance on significant surfaces of white corrosion
5.2 Preparation of Specimen—The test surface must be free
of fingerprints and other extraneous stains and must not be
1
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
cleaned except by gentle wiping with a clean, dry, soft cloth to
and Inorganic Coatingsand is the direct responsibility of Subcommittee B08.07 on
remove loose particles. Oily or greasy surfaces should not be
Conversion Coatings
used for testing, and degreasing with organic solvents is not
Current edition approved Nov. 1, 2014. Published November 2014. Originally
ε1
approved in 2000. Last previous edition approved in 2009 as B940– 05(2009) .
recommended.
DOI: 10.1520/B0940-05R14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Procedure
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Salt Spray Test—Expose the clean specimen to a 5 %
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. solution salt spray and conduct the test in accordance with the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
B940 − 05 (2014)
latest revision of Practice B117. Unless otherwise specified, gritless, soft gum eraser (art-gum)
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: B940 − 05 (Reapproved 2009) B940 − 05 (Reapproved 2014)
Standard Practice for
Testing Non-Chromate Coatings on Zinc and Cadmium
1
Surfaces
This standard is issued under the fixed designation B940; 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.
1
ε NOTE—The units statement in subsection (1.3) was added editorially in January 2010.
1. Scope
1.1 This practice covers a procedure for evaluating the protective value of chemical and electrochemical conversion coatings
produced by non-chromate (chromate being defined as a compound that has chromium in the plus six oxidation state, and as such,
chromium compounds in other oxidation states, such as plus three, shall not be excluded) treatments of zinc and cadmium surfaces.
1.2 The protective value of a non-chromate coating is usually determined by salt-spray test and by determining whether or not
the coating possesses adequate abrasion resistance when applied for that purpose.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
B117 Practice for Operating Salt Spray (Fog) Apparatus
3. Terminology
3.1 Descriptions of Terms:
3.1.1 time to failure—time to failure will depend on the type of coating tested. The minimum expected protective value
obtainable in a given salt spray test is given in Appendix X2.
1
This practice is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatingsand is the direct responsibility of Subcommittee B08.07 on Conversion
Coatings
Current edition approved Sept. 1, 2009Nov. 1, 2014. Published January 2009November 2014. Originally approved in 2000. Last previous edition approved in 20052009
ε1
as B940– 05.05(2009) . DOI: 10.1520/B0940-05R09E01.10.1520/B0940-05R14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.1.1.1 Discussion—
In most instances, failure is defined as the first appearance on significant surfaces of white corrosion products visible to the unaided
eye at normal reading distance, except that the presence of white corrosion products at sharp edges (for example, on threaded
fasteners) and at junctions between dissimilar metals should not be considered failure. In some instances, it may be desirable to
regard the first appearance of red rust as failure.
3.1.2 significant surfaces—in general, significant surfaces are those surfaces that are visible and subject to corrosion or wear,
or both, except that surfaces that are normally difficult to coat by electroplating or mechanical deposition may be exempt. The
designation of significant surfaces may be indicated on the drawing.
4. Significance and Use
4.1 This practice is applicable to non-chromate coatings that are colorless, colored, electrochemically applied or non-
electrochemically applied. The zinc or cadmium, or both, may be electrodeposited, mechanically deposited, hot-dipped, rolled, or
in the form of castings.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
B940 − 05 (2014)
4.2 Because of variables inherent in the salt-spray test which may differ from one test cabinet to another, interpretation of test
results for compliance with expected performance should be specified by the purchaser.
4.3 Properties such as thickness, color, luster, and ability to provide good paint adhesion are not covered in this practice, nor
are the chemical composition and the method of application of these finishes.
5. Conditioning
5.1 Aging—Before subjecting a non-chromate coating to test, check with the chemical producer to determine if aging is an issue
that needs to be considered.
5.2 Preparation of Specimen—The test surface must be free of fingerprints and other extran
...
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