ASTM G50-20

Standard Practice for Conducting Atmospheric Corrosion Tests on Metals

SIGNIFICANCE AND USE
3.1 The procedures described herein can be used to evaluate the corrosion resistance of metals when exposed to the weather, as well as to evaluate the relative corrosivity of the atmosphere at specific locations. Because of the variability and complexity of weather effects and the industrial and natural factors influencing the atmospheric corrosivity of a test site, a multi-year exposure period should be considered to minimize their influence. Also, as corrosivity may vary at a site from season to season, exposures should be made either at the same time of the year to minimize variability or these differences should be established by multiple exposures.  
3.2 Control specimens should always be employed in weathering tests. The control specimens should be from a material having established weathering characteristics. A substantial amount of corrosion data shall have been accumulated for the control specimens. It is also good practice to retain samples of all materials exposed so that possible effects of long-term aging can be measured.
SCOPE
1.1 This practice covers and defines conditions for exposure of metals and alloys to the weather. It sets forth the general procedures that should be followed in any atmospheric test. It is presented as an aid in conducting atmospheric corrosion tests so that some of the pitfalls of such testing may be avoided. As such, it is concerned mainly with panel exposures to obtain data for comparison purposes.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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 whoever uses this standard to consult and establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2020
• ICS: 77.060 - Corrosion of metals
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.04 - Corrosion of Metals in Natural Atmospheric and Aqueous Environments

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G50 − 20
Standard Practice for
1
Conducting Atmospheric Corrosion Tests on Metals
This standard is issued under the fixed designation G50; the number immediately following the designation indicates the year of original
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 sion Test Specimens
G33 Practice for Recording Data from Atmospheric Corro-
1.1 This practice covers and defines conditions for exposure
sion Tests of Metallic-Coated Steel Specimens
of metals and alloys to the weather. It sets forth the general
G46 Guide for Examination and Evaluation of Pitting Cor-
procedures that should be followed in any atmospheric test. It
rosion
ispresentedasanaidinconductingatmosphericcorrosiontests
G84 Practice for Measurement of Time-of-Wetness on Sur-
so that some of the pitfalls of such testing may be avoided.As
faces Exposed to Wetting Conditions as in Atmospheric
such, it is concerned mainly with panel exposures to obtain
Corrosion Testing
data for comparison purposes.
G91 Practice for Monitoring Atmospheric SO Deposition
2
1.2 The values stated in inch-pound units are to be regarded
Rate for Atmospheric Corrosivity Evaluation
as standard. The values given in parentheses are mathematical
G92 Practice for Characterization of Atmospheric Test Sites
conversions to SI units that are provided for information only
G140 Test Method for Determining Atmospheric Chloride
and are not considered standard.
Deposition Rate by Wet Candle Method
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Significance and Use
responsibility of whoever uses this standard to consult and
3.1 The procedures described herein can be used to evaluate
establish appropriate safety, health, and environmental prac-
thecorrosionresistanceofmetalswhenexposedtotheweather,
tices and determine the applicability of regulatory limitations
as well as to evaluate the relative corrosivity of the atmosphere
prior to use.
at specific locations. Because of the variability and complexity
1.4 This international standard was developed in accor-
of weather effects and the industrial and natural factors
dance with internationally recognized principles on standard-
influencing the atmospheric corrosivity of a test site, a multi-
ization established in the Decision on Principles for the
year exposure period should be considered to minimize their
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical influence.Also, as corrosivity may vary at a site from season to
Barriers to Trade (TBT) Committee. season, exposures should be made either at the same time of
the year to minimize variability or these differences should be
2. Referenced Documents
established by multiple exposures.
2
2.1 ASTM Standards:
3.2 Control specimens should always be employed in
A380/A380M Practice for Cleaning, Descaling, and Passi-
weathering tests. The control specimens should be from a
vation of Stainless Steel Parts, Equipment, and Systems
material having established weathering characteristics. A sub-
D2010/D2010M Test Methods for Evaluation of Total Sul-
stantial amount of corrosion data shall have been accumulated
fation Activity in the Atmosphere by the Lead Dioxide
for the control specimens. It is also good practice to retain
Technique
samples of all materials exposed so that possible effects of
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
long-term aging can be measured.
4. Test Sites
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.04 on Corrosion of
4.1 Test sites should be chosen at a number of locations
Metals in Natural Atmospheric and Aqueous Environments.
representative of the atmospheric environments where the
Current edition approved Nov. 1, 2020. Published November 2020. Originally
metals or alloys are likely to be used. If such information is not
approved in 1976. Last previous edition approved in 2015 as G50–10(2015). DOI:
10.1520/G0050-20.
available, the selection should include sites typical of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
industrial, rural, and marine atmospheres. Test site
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
characterization, if needed, shall be conducted in accordance
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website
...

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: G50 − 10 (Reapproved 2015) G50 − 20
Standard Practice for
1
Conducting Atmospheric Corrosion Tests on Metals
This standard is issued under the fixed designation G50; 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 practice covers and defines conditions for exposure of metals and alloys to the weather. It sets forth the general procedures
that should be followed in any atmospheric test. It is presented as an aid in conducting atmospheric corrosion tests so that some
of the pitfalls of such testing may be avoided. As such, it is concerned mainly with panel exposures to obtain data for comparison
purposes.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 whoever uses this standard to consult and establish appropriate safety safety, health, and healthenvironmental practices and
determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
A380A380/A380M Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
D2010/D2010M Test Methods for Evaluation of Total Sulfation Activity in the Atmosphere by the Lead Dioxide Technique
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
G33 Practice for Recording Data from Atmospheric Corrosion Tests of Metallic-Coated Steel Specimens
G46 Guide for Examination and Evaluation of Pitting Corrosion
G84 Practice for Measurement of Time-of-Wetness on Surfaces Exposed to Wetting Conditions as in Atmospheric Corrosion
Testing
G91 Practice for Monitoring Atmospheric SO Deposition Rate for Atmospheric Corrosivity Evaluation
2
G92 Practice for Characterization of Atmospheric Test Sites
G140 Test Method for Determining Atmospheric Chloride Deposition Rate by Wet Candle Method
3. Significance and Use
3.1 The procedures described herein can be used to evaluate the corrosion resistance of metals when exposed to the weather, as
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.04 on Atmospheric
CorrosionCorrosion of Metals in Natural Atmospheric and Aqueous Environments.
Current edition approved Nov. 1, 2015Nov. 1, 2020. Published December 2015November 2020. Originally approved in 1976. Last previous edition approved in 20102015
as G50G50–10(2015).–10. DOI: 10.1520/G0050-10R15.10.1520/G0050-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’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

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G50 − 20
well as to evaluate the relative corrosivity of the atmosphere at specific locations. Because of the variability and complexity of
weather effects and the industrial and natural factors influencing the atmospheric corrosivity of a test site, a multi-year exposure
period should be considered to minimize their influence. Also, as corrosivity may vary at a site from season to season, exposures
should be made either at the same time of the year to minimize variability or these differences should be established by multiple
exposures.
3.2 Control specimens should always be employed in weathering tests. The control specimens should be from a material having
established weathering characteristics. A substantial amount of corrosion data shall have been accumulated for the control
specimens. It is also good practice to retain samples of all mater
...