ASTM G28-22

Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys

SIGNIFICANCE AND USE
3.1 The boiling ferric sulfate-sulfuric acid test may be applied to the following alloys in the wrought condition:    
Alloy  
Testing Time, h  
N06007  
120  
N06022  
24  
N06030  
120  
N06059  
24  
N06200  
24  
N06455  
24  
N06600  
24  
N06625  
120  
N06686  
24  
N06985  
120  
N08020  
120  
N08367  
24  
Alloy  
Testing Time, h  
N08800  
120  
N08825A  
120  
N10276  
24(A) While the ferric sulfate-sulfuric acid test does detect susceptibility to inter- granular corrosion in Alloy N08825, the boiling 65 % nitric acid test, Practices A262, Practice C, for detecting susceptibility to intergranular corrosion in stainless steels is more sensitive and should be used if the intended service is nitric acid.  
3.2 This test method may be used to evaluate as-received material and to evaluate the effects of subsequent heat treatments. In the case of nickel-rich, chromium-bearing alloys, the test method may be applied to wrought and weldments of products. The test method is not applicable to cast products.
SCOPE
1.1 These test methods cover two tests as follows:  
1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3 – 10, inclusive)—This test method describes the procedure for conducting the boiling ferric sulfate—50 % sulfuric acid test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to intergranular corrosion (see Terminology G193), which may be encountered in certain service environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022, N06059, and N06455.  
1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11 – 18, inclusive)—This test method describes the procedure for conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increase in corrosion rate when there are high levels of grain boundary precipitation.  
1.2 The purpose of these two test methods is to detect susceptibility to intergranular corrosion as influenced by variations in processing or composition, or both. Materials shown to be susceptible may or may not be intergranularly corroded in other environments. This must be established independently by specific tests or by service experience.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3.1 Exception—Some desired corrosion rate units in 8.1.1 are given in inch-pound units.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Warning statements are given in 5.1.1, 5.1.3, 5.1.9, 13.1.1, and 13.1.11.  
1.5 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-Nov-2022
• ICS: 77.120.40 - Nickel, chromium and their alloys
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.05 - Laboratory Corrosion Tests

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: G28 − 22
Standard Test Methods for
Detecting Susceptibility to Intergranular Corrosion in
1
Wrought, Nickel-Rich, Chromium-Bearing Alloys
ThisstandardisissuedunderthefixeddesignationG28;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 1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 These test methods cover two tests as follows:
responsibility of the user of this standard to establish appro-
1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections
priate safety, health, and environmental practices and deter-
3–10, inclusive)—This test method describes the procedure
mine the applicability of regulatory limitations prior to use.
for conducting the boiling ferric sulfate—50 % sulfuric acid
Warning statements are given in 5.1.1, 5.1.3, 5.1.9, 13.1.1, and
test which measures the susceptibility of certain nickel-rich,
13.1.11.
chromium-bearing alloys to intergranular corrosion (see Ter-
1.5 This international standard was developed in accor-
minology G193), which may be encountered in certain service
dance with internationally recognized principles on standard-
environments. The uniform corrosion rate obtained by this test
ization established in the Decision on Principles for the
method, which is a function of minor variations in alloy
Development of International Standards, Guides and Recom-
composition, may easily mask the intergranular corrosion
mendations issued by the World Trade Organization Technical
components of the overall corrosion rate on alloys N10276,
Barriers to Trade (TBT) Committee.
N06022, N06059, and N06455.
1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections
2. Referenced Documents
11–18, inclusive)—This test method describes the procedure
2
2.1 ASTM Standards:
for conducting a boiling 23 % sulfuric + 1.2 % hydrochlo-
A262 Practices for Detecting Susceptibility to Intergranular
ric+1% ferric chloride+1% cupric chloride test which
Attack in Austenitic Stainless Steels
measures the susceptibility of certain nickel-rich, chromium-
D1193 Specification for Reagent Water
bearing alloys to display a step function increase in corrosion
G193 Terminology and Acronyms Relating to Corrosion
rate when there are high levels of grain boundary precipitation.
1.2 The purpose of these two test methods is to detect
METHOD A—Ferric Sulfate—Sulfuric Acid Test
susceptibility to intergranular corrosion as influenced by varia-
3. Significance and Use
tionsinprocessingorcomposition,orboth.Materialsshownto
be susceptible may or may not be intergranularly corroded in
3.1 The boiling ferric sulfate-sulfuric acid test may be
other environments.This must be established independently by
applied to the following alloys in the wrought condition:
specific tests or by service experience.
Alloy Testing Time, h
1.3 The values stated in SI units are to be regarded as
N06007 120
standard. No other units of measurement are included in this
N06022 24
N06030 120
standard.
N06059 24
1.3.1 Exception—Some desired corrosion rate units in 8.1.1
N06200 24
are given in inch-pound units.
N06455 24
N06600 24
N06625 120
N06686 24
N06985 120
N08020 120
N08367 24
1
These test methods are under the jurisdiction of ASTM Committee G01 on
Corrosion of Metals and are the direct responsibility of Subcommittee G01.05 on
2
Laboratory Corrosion Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2022. Published January 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1971. Last previous edition approved in 2015 as G28–02 (2015). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0028-22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G28−22
5.1.3 Then measure 236 mL of reagent-grade sulfuric acid
Alloy Testing Time, h
(H SO ) of a concentration which must be in the range from
2 4
N08800 120
95.0 weight percent to 98.0 weight percent in a 250 mL
A
N08825 120
graduate.Add the acid slowly to the water in the flask to avoid
N10276 24
boiling by the heat evolved (Note 3). Externally cooling the
A
While the ferric sulfate-sulfuric aci
...

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: G28 − 02 (Reapproved 2015) G28 − 22
Standard Test Methods for
Detecting Susceptibility to Intergranular Corrosion in
1
Wrought, Nickel-Rich, Chromium-Bearing Alloys
This standard is issued under the fixed designation G28; 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 These test methods cover two tests as follows:
1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3 – 10, inclusive)—This test method describes the procedure for
conducting the boiling ferric sulfate—50 % sulfuric acid test which measures the susceptibility of certain nickel-rich,
chromium-bearing alloys to intergranular corrosion (see Terminology G15G193), which may be encountered in certain service
environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy
composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022,
N06059, and N06455.
1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11 – 18, inclusive)—This test method describes the procedure for
conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the
susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increase in corrosion rate when there are
high levels of grain boundary precipitation.
1.2 The purpose of these two test methods is to detect susceptibility to intergranular corrosion as influenced by variations in
processing or composition, or both. Materials shown to be susceptible may or may not be intergranularly corroded in other
environments. This must be established independently by specific tests or by service experience.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3.1 Exception—Some desired corrosion rate units in 8.1.1 are given in inch-pound units.
1
These test methods are under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and are the direct responsibility of Subcommittee G01.05 on Laboratory
Corrosion Tests.
Current edition approved Nov. 1, 2015Dec. 1, 2022. Published November 2015January 2023. Originally approved in 1971. Last previous edition approved in 20082015
as G28–02 (2008).(2015). DOI: 10.1520/G0028-02R15.10.1520/G0028-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G28 − 22
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Warning statements are given in 5.1.1, 5.1.3, 5.1.9, 13.1.1, and 13.1.11.
1.5 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:
A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
D1193 Specification for Reagent Water
G15G193 Terminology and Acronyms Relating to Corrosion and Corrosion Testing (Withdrawn 2010)
METHOD A—Ferric Sulfate—Sulfuric Acid Test
3. Significance and Use
3.1 The boiling ferric sulfate-sulfuric acid test may be applied to the following alloys in the wrought condition:
Alloy Testing Time, h
N06007 120
N06007 120
N06022 24
N06030 120
N06059 24
N06200 24
N06455 24
N06600 24
N06625 120
N06686 24
N06985 120
N08020 120
N08367 24
Alloy Testing Time, h
N08800 120
A
N08825 120
N10276 24
A
While the ferric sulfate-sulfuric acid test does detect susceptibility to inter- granular corrosion in Alloy N08825, the boiling 65 % nitric acid test, Practices A262, Practice
C, for detecting susceptibility to intergranular corrosion in stainless steels is more sensitive and sh
...