ASTM G44-21

Standard Practice for Exposure of Metals and Alloys by Alternate Immersion in Neutral 3.5 % Sodium Chloride Solution

SIGNIFICANCE AND USE
4.1 The 3.5 % NaCl alternate immersion procedure is a general, all-purpose procedure that produces valid comparisons for most metals, particularly when specimens are exposed at high levels of applied stress or stress intensity.  
4.2 While the alternate immersion test is an accelerated test and is considered to be representative of certain natural conditions, it is not intended to predict performance in specialized chemical environments in which a different mode of cracking may be operative. For example, it does not predict the performance of aluminum alloys in highly acidic environments such as heated inhibited red fuming nitric acid (IRFNA). For such cases, the results of the alternate immersion test are of doubtful significance until a relationship has been established between it and anticipated service environments.  
4.3 While this practice is applicable in some degree to all metals, it is not equally discriminative of all alloys, even within the same metal system. Consequently, information should be established to allow comparisons of performances of the alloy of interest in the alternate immersion test and in natural environments.
Note 2: The alternate immersion concept can be useful for exposure of corrosion specimens in other solutions because the procedure and apparatus provide a controlled set of conditions. Details of this are beyond the scope of this practice.
SCOPE
1.1 This practice covers procedures for making alternate immersion stress corrosion tests in 3.5 % sodium chloride (NaCl) (Note 1). It is primarily for tests of aluminum alloys (Test Method G47) and ferrous alloys, but may be used for other metals exhibiting susceptibility to chloride ions. It sets forth the environmental conditions of the test and the means for controlling them.
Note 1: Alternate immersion stress corrosion exposures are sometimes made in substitute ocean water (without heavy metals) prepared in accordance with Practice D1141. The general requirements of this present practice are also applicable to such exposures except that the reagents used, the solution concentration, and the solution pH should be as specified in Practice D1141.  
1.2 This practice can be used for both stressed and unstressed corrosion specimens. Historically, it has been used for stress-corrosion cracking testing, but is often used for other forms of corrosion, such as uniform, pitting, intergranular, and galvanic.  
1.3 This practice is intended for alloy development and for applications where the alternate immersion test is to serve as a control test on the quality of successive lots of the same material. Therefore, strict test conditions are stipulated for maximum assurance that variations in results are attributable to variations in the material being tested.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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: 30-Apr-2021
• ICS: 77.040.30 - Chemical analysis of metals
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.06 - Environmentally Assisted Cracking

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: G44 − 21
Standard Practice for
Exposure of Metals and Alloys by Alternate Immersion in
1
Neutral 3.5 % Sodium Chloride Solution
ThisstandardisissuedunderthefixeddesignationG44;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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This practice covers procedures for making alternate
ization established in the Decision on Principles for the
immersion stress corrosion tests in 3.5 % sodium chloride
Development of International Standards, Guides and Recom-
(NaCl) (Note 1). It is primarily for tests of aluminum alloys
mendations issued by the World Trade Organization Technical
(Test Method G47) and ferrous alloys, but may be used for
Barriers to Trade (TBT) Committee.
other metals exhibiting susceptibility to chloride ions. It sets
forththeenvironmentalconditionsofthetestandthemeansfor
2. Referenced Documents
controlling them.
2
2.1 ASTM Standards:
NOTE 1—Alternate immersion stress corrosion exposures are some-
D1141 Practice for the Preparation of Substitute Ocean
times made in substitute ocean water (without heavy metals) prepared in
Water
accordance with Practice D1141. The general requirements of this present
D1193 Specification for Reagent Water
practice are also applicable to such exposures except that the reagents
used, the solution concentration, and the solution pH should be as G1 Practice for Preparing, Cleaning, and Evaluating Corro-
specified in Practice D1141.
sion Test Specimens
G47 Test Method for Determining Susceptibility to Stress-
1.2 This practice can be used for both stressed and un-
Corrosion Cracking of 2XXX and 7XXX Aluminum
stressed corrosion specimens. Historically, it has been used for
Alloy Products
stress-corrosion cracking testing, but is often used for other
forms of corrosion, such as uniform, pitting, intergranular, and
3. Summary of Practice
galvanic.
3.1 The alternate immersion test utilizes a 1 h cycle that
1.3 This practice is intended for alloy development and for
includes a 10 min period in an aqueous solution of 3.5 %
applications where the alternate immersion test is to serve as a
sodium chloride (NaCl) followed by a 50 min period out of the
control test on the quality of successive lots of the same
solution, during which the specimens are allowed to dry. This
material. Therefore, strict test conditions are stipulated for
1 h cycle is continued 24 h/day for the total number of days
maximumassurancethatvariationsinresultsareattributableto
recommended for the particular alloy being tested. Typically,
variations in the material being tested.
aluminum and ferrous alloys are exposed from 20 days to 90
1.4 The values stated in SI units are to be regarded as
days or longer, depending upon the resistance of the alloy to
standard. The values given in parentheses after SI units are
corrosion by saltwater.
provided for information only and are not considered standard.
4. Significance and Use
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.1 The 3.5 % NaCl alternate immersion procedure is a
responsibility of the user of this standard to establish appro-
general,all-purposeprocedurethatproducesvalidcomparisons
priate safety, health, and environmental practices and deter- for most metals, particularly when specimens are exposed at
mine the applicability of regulatory limitations prior to use.
high levels of applied stress or stress intensity.
4.2 While the alternate immersion test is an accelerated test
and is considered to be representative of certain natural
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.06 on Environmen-
2
tally Assisted Cracking. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2021. Published June 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1975. Last previous edition approved in 2013 as G44 – 99 (2013). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0044-21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. U
...

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: G44 − 99 (Reapproved 2013) G44 − 21
Standard Practice for
Exposure of Metals and Alloys by Alternate Immersion in
1
Neutral 3.5 % Sodium Chloride Solution
This standard is issued under the fixed designation G44; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This practice covers procedures for making alternate immersion stress corrosion tests in 3.5 % sodium chloride (NaCl) (Note
1). It is primarily for tests of aluminum alloys (Test Method G47) and ferrous alloys, but may be used for other metals exhibiting
susceptibility to chloride ions. It sets forth the environmental conditions of the test and the means for controlling them.
NOTE 1—Alternate immersion stress corrosion exposures are sometimes made in substitute ocean water (without heavy metals) prepared in accordance
with SpecificationPractice D1141. The general requirements of this present practice are also applicable to such exposures except that the reagents used,
the solution concentration, and the solution pH should be as specified in SpecificationPractice D1141.
1.2 This practice can be used for both stressed and unstressed corrosion specimens. Historically, it has been used for
stress-corrosion cracking testing, but is often used for other forms of corrosion, such as uniform, pitting, intergranular, and
galvanic.
1.3 This practice is intended for alloy development and for applications where the alternate immersion test is to serve as a control
test on the quality of successive lots of the same material. Therefore, strict test conditions are stipulated for maximum assurance
that variations in results are attributable to variations in the material being tested.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.after
SI units are provided for information only and are not considered standard.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 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:
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.06 on Environmentally
Assisted Cracking.
Current edition approved May 1, 2013May 1, 2021. Published July 2013June 2021. Originally approved in 1975. Last previous edition approved in 20052013 as G44 – 99
(2005).(2013). DOI: 10.1520/G0044-99R13.10.1520/G0044-21.
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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G44 − 21
D1141 Practice for the Preparation of Substitute Ocean Water
D1193 Specification for Reagent Water
E3 Guide for Preparation of Metallographic Specimens
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
G16 Guide for Applying Statistics to Analysis of Corrosion Data
G47 Test Method for Determining Susceptibility to Stress-Corrosion Cracking of 2XXX and 7XXX Aluminum Alloy Products
3. Summary of Practice
3.1 The alternate immersion test utilizes a 1-h1 h cycle that includes a 10-min10 min period in an aqueous solution of 3.5 %
sodium chloride (NaCl) followed by a 50-min50 min period out of the solution, during which the specimens are allowed to dry.
This 1-h1 h cycle is continued 24 h/day for the total number of days recommended for the particular alloy being tested. Typica
...