ASTM G149-97
(Practice)Standard Practice for Conducting the Washer Test for Atmospheric Galvanic Corrosion (Withdrawn 2004)
Standard Practice for Conducting the Washer Test for Atmospheric Galvanic Corrosion (Withdrawn 2004)
SCOPE
1.1 This practice covers the evaluation of atmospheric galvanic corrosion of any materials that can be made into washers.
1.2 The washer, or disk, test was used by H. O. teeple in 1949 for a series of exposures for ASTM Committee B03.08 on Corrosion of Non-Ferrous Metals and Alloys. Since that time, ASTM has refined the test and conducted other investigations using this practice.
1.3 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.
WITHDRAWN RATIONALE
This practice covers the evaluation of atmospheric galvanic corrosion of any materials that can be made into washers.
Formerly under the jurisdiction of Committee G02 on Wear and Erosion, this practice was withdrawn in October 2004 because the Washer Test for Atmospheric Galvanic Corrosion is no longer used as a measure of galvanic corrosion rates.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G 149 – 97
Standard Practice for
Conducting the Washer Test for Atmopsheric Galvanic
Corrosion
This standard is issued under the fixed designation G 149; 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 G 82 Guide for Development and Use of a Galvanic Series
for Predicting Galvanic Corrosion Performance
1.1 This practice covers the evaluation of atmospheric
G 84 Practice for Measurement of Time-of-Wetness on
galvanic corrosion of any materials that can be made into
Surfaces Exposed to Wetting Conditions as in Atmospheric
washers.
Corrosion Testing
1.2 The washer, or disk, test was used by H. O. Teeple in
2 G 91 Practice for Monitoring Atmopsheric SO Using the
1949 for a series of exposures for ASTM Committee B 03.08 2
Sulfation Plate Technique
on Corrosion of Non-Ferrous Metals and Alloys. Since that
G 92 Practice for Characterization of Atmospheric Test
time, ASTM has refined the test and conducted other investi-
3,4,5
Sites
gations using this practice.
G 104 Test Method for Assessing Galvanic Corrosion
1.3 This standard does not purport to address all of the
Caused by the Atmosphere
safety concerns, if any, associated with its use. It is the
G 116 Practice for Conducting Wire-on-Bolt Test for Atmo-
responsibility of the user of this standard to establish appro-
spheric Galvanic Corrosion
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
3. Terminology
2. Referenced Documents 3.1 For definitions of terms used in this practice, refer to
Terminology G 15. For conventions related to this practice,
2.1 ASTM Standards:
refer to Practice G 3.
G 1 Practice for Preparing, Cleaning, and Evaluating Cor-
rosion Test Specimens
4. Summary of Practice
G 3 Practice for Conventions Applicable to Electrochemical
6 4.1 The practice consists of atmospheric exposure of speci-
Measurements in Corrosion Testing
men assemblies, each consisting of a set of four washers,
G 15 Terminology Relating to Corrosion and Corrosion
6 graduated in size with alternating anode and cathode materials,
Testing
bolted together through center holes. Only the center two
G 16 Guide for Applying Statistics to Analysis of Corrosion
6 washers are used for the analysis, the outer washers being used
Data
only to establish the proper environment on the inner washers.
G 50 Practice for Conducting Atmospheric Corrosion Tests
6 Mass loss of the washers is determined after the exposure.
on Metals
Reference assemblies of the anode material are exposed
concurrently to allow for separation of general and crevice
corrosion effects from galvanic corrosion effects.
This practice is under the jurisdiction of ASTM Committee G-1 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.04 on Atmospheric
5. Significance and Use
Corrosion.
5.1 The arrangement of the washers gives close to a 1:1
Current edition approved Apr. 10, 1997. Published November 1997.
Teeple, H. O., Symposium on Atmospheric Corrosion of Non-Ferrous Metals, cathode-to-anode area ratio, making this test less severe than
ASTM STP 175, ASTM, 1955, pp. 89–113.
the wire-on-bolt test described in Practice G 116 and similar in
Baboian, R., “Final Report on the ASTM Study: Atmospheric Galvanic
severity to the plate test described in Test Method G 104. As in
Corrosion of Magnesium Coupled to Other Metals,” Atmospheric Factors Affecting
the plate test, typical exposure periods range from 1 to 20
the Corrosion of Engineering Materials, ASTM STP 646, Coburn, S. Ed., ASTM
1978, pp. 17–24.
years.
Blum, W., Symposium on Properties, Tests and Performance of Electrodepos-
5.2 The major advantage of this test over other atmospheric
ited Metallic Coatings, ASTM STP 197, ASTM, 1956, p. 49.
5 galvanic corrosion tests standardized by ASTM is that material
ASTM Proceedings, Vol 41, No. 170, 1941.
Annual Book of ASTM Standards, Vol 03.02. for this test may be easier to obtain than material for the other
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G 149
tests, in that only small pieces of thin sheet are required. In 7.1.6 Remove metal burrs from the edges of the specimens
addition, the washer test is probably the easiest of the three and bolt holes. All surfaces should be free from visible defects
tests standardized by ASTM to setup and evaluate. such as heat-treatment scale, blisters, cracks, porosity,
5.3 The anode/cathode relationship of the materials in- scratches, and so forth. A surface finish of 0.4 to 0.5-μm (16 to
volved need not be known beforehand, so information such as 20 micro in.) is recommended.
that in Guide G 82 is not required. 7.1.7 Do not mark the specimens, since there is no appro-
5.4 Unlike the plate test, the washer test yields only corro- priate place to do so, however metal tags may be affixed to the
sion rate information, and it is difficult to determine corrosion completed assemblies outside of the Bakelite washers, if
morphology visually due to the shape of the components. It is desired.
also difficult to determine changes in mechanical properties 7.1.8 Additional washers of the anode material must be
with this test. Test Method G 104 is preferable for determining prepared to enable the construction of reference assemblies,
morphology and mechanical property changes. where all four washers are made of the anode material and
exposed under identical conditions to the test assemblies.
6. Interferences
Where the anode material is not known beforehand, reference
6.1 The manufacturing process used to make the sheet may
assemblies of both materials should be constructed. The
affect corrosion potentials and polarization behavior. Material reference assemblies are used to assess non-galvanic effects
in this form may not behave galvanically the same as material
such as general or crevice corrosion, or exfoliation.
in the form of interest, such as fasteners in sheet roofing for 7.1.9 For reasonable statistical validity, at least three assem-
example.
blies of each type should be prepared and tested for each
exposure duration evaluated.
7. Procedure
7.2 Making the Assemblies:
7.1 The Components:
7.2.1 All parts should be thoroughly cleaned and degreased
7.1.1 The components used to construct the specimen as-
before assembly, according to Practice G 1. After degreasing,
semblies for this test are shown in Fig. 1.
the plates should only be handled by the edges while wearing
7.1.2 Washers 1.6 mm ( ⁄16 in.) thick of one material are
clean, cotton gloves.
manufactured with outside diameters of 25.4 mm and 33.5 mm
7.2.2 If the relative anode/cathode relationship of the mate-
(1.00 in. and 1.32 in.), while the other material in the galvanic
rials is not known at the start of the test, all plates should be
couple is made into washers of identical thickness with outside
massed before assembly, otherwise, only the anode plates need
diameters of 30.0 mm and 36.6 mm (1.18 in. and 1.44 in.).
be massed.
Washer dimensions are
...
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