ASTM G71-81(2014)
(Guide)Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes
Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes
SIGNIFICANCE AND USE
3.1 Use of this guide is intended to provide information on the galvanic corrosion of metals in electrical contact in an electrolyte that does not have a flow velocity sufficient to cause erosion-corrosion or cavitation.
3.2 This standard is presented as a guide for conducting galvanic corrosion tests in liquid electrolyte solutions, both in the laboratory and in service environments. Adherence to this guide will aid in avoiding some of the inherent difficulties in such testing.
SCOPE
1.1 This guide covers conducting and evaluating galvanic corrosion tests to characterize the behavior of two dissimilar metals in electrical contact in an electrolyte under low-flow conditions. It can be adapted to wrought or cast metals and alloys.
1.2 This guide covers the selection of materials, specimen preparation, test environment, method of exposure, and method for evaluating the results to characterize the behavior of galvanic couples in an electrolyte. Note 1—Additional information on galvanic corrosion testing and examples of the conduct and evaluation of galvanic corrosion tests in electrolytes are given in Refs (1)2 through (2).
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: G71 − 81 (Reapproved 2014)
Standard Guide for
Conducting and Evaluating Galvanic Corrosion Tests in
1
Electrolytes
ThisstandardisissuedunderthefixeddesignationG71;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope G16 Guide for Applying Statistics to Analysis of Corrosion
Data
1.1 This guide covers conducting and evaluating galvanic
G31 Guide for Laboratory Immersion Corrosion Testing of
corrosion tests to characterize the behavior of two dissimilar
Metals
metals in electrical contact in an electrolyte under low-flow
G46 Guide for Examination and Evaluation of Pitting Cor-
conditions. It can be adapted to wrought or cast metals and
rosion
alloys.
1.2 This guide covers the selection of materials, specimen
3. Significance and Use
preparation,testenvironment,methodofexposure,andmethod
3.1 Use of this guide is intended to provide information on
for evaluating the results to characterize the behavior of
the galvanic corrosion of metals in electrical contact in an
galvanic couples in an electrolyte.
electrolytethatdoesnothaveaflowvelocitysufficienttocause
NOTE 1—Additional information on galvanic corrosion testing and erosion-corrosion or cavitation.
examples of the conduct and evaluation of galvanic corrosion tests in
2 3.2 This standard is presented as a guide for conducting
electrolytes are given in Refs (1) through (2).
galvanic corrosion tests in liquid electrolyte solutions, both in
1.3 The values stated in SI units are to be regarded as
the laboratory and in service environments. Adherence to this
standard. No other units of measurement are included in this
guide will aid in avoiding some of the inherent difficulties in
standard.
such testing.
1.4 This standard does not purport to address all of the
4. Test Specimens
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 Material—Test specimens should be manufactured from
priate safety and health practices and determine the applica-
thesamematerialasthoseusedintheserviceapplicationbeing
bility of regulatory limitations prior to use.
modeled. Minor compositional or processing differences be-
tween materials or between different heats can greatly affect
2. Referenced Documents
the results in some cases.
3
2.1 ASTM Standards:
4.2 Size and Shape:
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
4.2.1 Thesizeandshapeofthetestspecimensaredependent
sion Test Specimens
on restrictions imposed by the test location. When determining
G3 Practice for Conventions Applicable to Electrochemical
material behavior in the laboratory, it is advisable to use the
Measurements in Corrosion Testing
largest specimens permissible within the constraints of the test
G4 Guide for Conducting Corrosion Tests in Field Applica-
equipment.Ingeneral,theratioofsurfaceareatometalvolume
tions
should be large in order to favor maximum corrosion loss per
weight. Sufficient thickness should be employed, however, to
minimize the possibility of perforation of the specimens during
1
This guide is under the jurisdiction ofASTM Committee G01 on Corrosion of
the test exposure. When modeling large components, the size
Metals and is the direct responsibility of Subcommittee G01.11 on Electrochemical
Measurements in Corrosion Testing.
of the specimens should be as large as practical. When
Current edition approved May 1, 2014. Published May 2014. Originally
modeling smaller components, specimen size should be as
approved in 1981. Last previous edition approved in 2009 as G71–81(2009). DOI:
close as possible to that of the application being modeled.
10.1520/G0071-81R14.
2
Surface area ratio in the test should be identical to the
The boldface numbers in parentheses refer to a list of references at the end of
this standard.
application being modeled. This ratio is defined as the surface
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
area of one member of the couple divided by the surface area
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
of the other member of the couple. Only the area in contact
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. with the electrolyte (wetted area) is used in this calculation. In
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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G71 − 81 (2014)
low-resistivity electrolytes, maintaining proximity between the volume of test solution may be varied to closely appro
...
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.
Designation: G71 − 81 (Reapproved 2009) G71 − 81 (Reapproved 2014)
Standard Guide for
Conducting and Evaluating Galvanic Corrosion Tests in
1
Electrolytes
This standard is issued under the fixed designation G71; 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
1.1 This guide covers conducting and evaluating galvanic corrosion tests to characterize the behavior of two dissimilar metals
in electrical contact in an electrolyte under low-flow conditions. It can be adapted to wrought or cast metals and alloys.
1.2 This guide covers the selection of materials, specimen preparation, test environment, method of exposure, and method for
evaluating the results to characterize the behavior of galvanic couples in an electrolyte.
NOTE 1—Additional information on galvanic corrosion testing and examples of the conduct and evaluation of galvanic corrosion tests in electrolytes
2
are given in Refs (1) through (2).
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
3
2.1 ASTM Standards:
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
G3 Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing
G4 Guide for Conducting Corrosion Tests in Field Applications
G16 Guide for Applying Statistics to Analysis of Corrosion Data
G31 Guide for Laboratory Immersion Corrosion Testing of Metals
G46 Guide for Examination and Evaluation of Pitting Corrosion
3. Significance and Use
3.1 Use of this guide is intended to provide information on the galvanic corrosion of metals in electrical contact in an electrolyte
that does not have a flow velocity sufficient to cause erosion-corrosion or cavitation.
3.2 This standard is presented as a guide for conducting galvanic corrosion tests in liquid electrolyte solutions, both in the
laboratory and in service environments. Adherence to this guide will aid in avoiding some of the inherent difficulties in such testing.
4. Test Specimens
4.1 Material—Test specimens should be manufactured from the same material as those used in the service application being
modeled. Minor compositional or processing differences between materials or between different heats can greatly affect the results
in some cases.
4.2 Size and Shape:
4.2.1 The size and shape of the test specimens are dependent on restrictions imposed by the test location. When determining
material behavior in the laboratory, it is advisable to use the largest specimens permissible within the constraints of the test
1
This guide is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.11 on Electrochemical
Measurements in Corrosion Testing.
Current edition approved May 1, 2009May 1, 2014. Published May 2009May 2014. Originally approved in 1981. Last previous edition approved in 20032009 as
G71–81(2003).G71–81(2009). DOI: 10.1520/G0071-81R09.10.1520/G0071-81R14.
2
The boldface numbers in parentheses refer to a list of references at the end of this standard.
3
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
G71 − 81 (2014)
equipment. In general, the ratio of surface area to metal volume should be large in order to favor maximum corrosion loss per
weight. Sufficient thickness should be employed, however, to minimize the possibility of perforation of the specimens during the
test exposure. When modeling large components, the size of the specimens should be as large as practical. When modeling smaller
components, specimen size should be as close as possible to that of the application being modeled. Surface
...
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