ASTM A763-15(2021)

Standard Practices for Detecting Susceptibility to Intergranular Attack in Ferritic Stainless Steels

ABSTRACT
This practices covers the detecting susceptibility to intergranular attack in ferritic stainless steel. Different method of preparing steel test specimens are presented. Four practices, including Practice W, X, Y, and Z, are used for determining susceptibility to intergranular attack in ferritic stainless steel. These practices cover the following tests; oxalic acid etch test, ferritic sulphate-sulfuric acid test, copper-copper sulphate-50% sulfuric acid test, and copper-copper sulphate-16% sulfuric acid test. Test specimens shall be examined for the ferritic sulphate-sulfuric acid test and copper-copper sulphate-50% sulphuric acid test under a binocular microscope at 40x magnification. The bend test evaluations for the steel test specimens are presented.
SCOPE
1.1 These practices cover the following four tests:  
1.1.1 Practice W—Oxalic acid etch test for detecting susceptibility to intergranular attack in stabilized ferritic stainless steels by classification of the etching structures (see Sections 3 – 10).  
1.1.2 Practice X—Ferric sulfate-sulfuric acid test for detecting susceptibility to intergranular attack in ferritic stainless steels (Sections 11 – 16).  
1.1.3 Practice Y—Copper-copper sulfate-50 % sulfuric acid test for detecting susceptibility to intergranular attack in ferritic stainless steels (Sections 17 – 22).  
1.1.4 Practice Z—Copper-copper sulfate-16 % sulfuric acid test for detecting susceptibility to intergranular attack in ferritic stainless steels (Sections 23 – 29).  
1.2 The following factors govern the application of these practices (1-6):2  
1.2.1 Practice W, oxalic acid test, is a rapid method of identifying, by simple electrolytic etching, those specimens of certain ferritic alloys that are not susceptible to intergranular corrosion associated with chromium carbide precipitation. Practice W is used as a screening test to avoid the necessity, for acceptable specimens, of more extensive testing required by Practices X, Y, and Z. See Table 1 for a listing of alloys for which Practice W is appropriate.    
1.2.2 Practices X, Y, and Z can be used to detect the susceptibility of certain ferritic alloys to intergranular attack associated with the precipitation of chromium carbides or nitrides.  
1.2.3 Practices W, X, Y, and Z can also be used to evaluate the effect of heat treatment or of fusion welding on susceptibility to intergranular corrosion.  
1.2.4 Table 2 lists the identification ferritic stainless steels for which data on the application of at least one of the standard practices is available.    
1.2.5 Some stabilized ferritic stainless steels may show high rates when tested by Practice X because of metallurgical factors not associated with chromium carbide or nitride precipitation. This possibility must be considered in selecting the test method. Combinations of alloys and test methods for which successful experience is available are shown in Table 1. Application of these standard tests to the other ferritic stainless steels will be by specific agreement between producer and user.  
1.3 Depending on the test and alloy, evaluations may be accomplished by weight loss determination, microscopical examination, or bend test (Sections 30 and 31). The choices are listed in Table 1.  
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. For specific safety precautionary statements, see 3.2.5, Section 7, 13.1, and 19.1.  
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...

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 77.140.20 - Stainless steels
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.14 - Methods of Corrosion Testing

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: A763 − 15 (Reapproved 2021)
Standard Practices for
Detecting Susceptibility to Intergranular Attack in Ferritic
1
Stainless Steels
This standard is issued under the fixed designation A763; 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.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.2.4 Table 2 lists the identification ferritic stainless steels
forwhichdataontheapplicationofatleastoneofthestandard
1.1 These practices cover the following four tests:
practices is available.
1.1.1 Practice W—Oxalic acid etch test for detecting sus-
1.2.5 Somestabilizedferriticstainlesssteelsmayshowhigh
ceptibility to intergranular attack in stabilized ferritic stainless
rates when tested by Practice X because of metallurgical
steels by classification of the etching structures (see Sections 3
factors not associated with chromium carbide or nitride pre-
–10).
cipitation. This possibility must be considered in selecting the
1.1.2 PracticeX—Ferricsulfate-sulfuricacidtestfordetect-
test method. Combinations of alloys and test methods for
ing susceptibility to intergranular attack in ferritic stainless
which successful experience is available are shown in Table 1.
steels (Sections11–16).
Applicationofthesestandardteststotheotherferriticstainless
1.1.3 Practice Y—Copper-copper sulfate-50% sulfuric acid
steelswillbebyspecificagreementbetweenproduceranduser.
testfordetectingsusceptibilitytointergranularattackinferritic
stainless steels (Sections17–22).
1.3 Depending on the test and alloy, evaluations may be
1.1.4 Practice Z—Copper-copper sulfate-16% sulfuric acid
accomplished by weight loss determination, microscopical
testfordetectingsusceptibilitytointergranularattackinferritic
examination,orbendtest(Sections30and31).Thechoicesare
stainless steels (Sections23–29).
listed in Table 1.
1.2 The following factors govern the application of these
1.4 This standard does not purport to address all of the
2
practices (1-6):
safety concerns, if any, associated with its use. It is the
1.2.1 Practice W, oxalic acid test, is a rapid method of
responsibility of the user of this standard to establish appro-
identifying, by simple electrolytic etching, those specimens of
priate safety, health, and environmental practices and deter-
certain ferritic alloys that are not susceptible to intergranular
mine the applicability of regulatory limitations prior to use.
corrosion associated with chromium carbide precipitation.
For specific safety precautionary statements, see 3.2.5, Section
PracticeWisusedasascreeningtesttoavoidthenecessity,for
7, 13.1, and 19.1.
acceptable specimens, of more extensive testing required by
1.5 This international standard was developed in accor-
Practices X, Y, and Z. See Table 1 for a listing of alloys for
dance with internationally recognized principles on standard-
which Practice W is appropriate.
ization established in the Decision on Principles for the
1.2.2 Practices X, Y, and Z can be used to detect the
Development of International Standards, Guides and Recom-
susceptibility of certain ferritic alloys to intergranular attack
mendations issued by the World Trade Organization Technical
associated with the precipitation of chromium carbides or
Barriers to Trade (TBT) Committee.
nitrides.
1.2.3 Practices W, X, Y, and Z can also be used to evaluate
2. Referenced Documents
the effect of heat treatment or of fusion welding on suscepti-
3
bility to intergranular corrosion. 2.1 ASTM Standards:
A370Test Methods and Definitions for Mechanical Testing
1 of Steel Products
These practices are under the jurisdiction of ASTM Committee A01 on Steel,
StainlessSteelandRelatedAlloysandarethedirectresponsibilityofSubcommittee
A01.14 on Methods of Corrosion Testing.
Current edition approved Sept. 1, 2021. Published September 2021. Originally
3
approved in 1979. Last previous edition approved in 2015 as A763–15. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/A0763-15R21. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to the list of references appended to Standards volume information, refer to the standard’s Document Summary page on
these practices. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
A763 − 15 (2021)
TABLE 1 Methods for Evaluating Ferritic Stainless S
...