ASTM A262-98
(Practice)Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
SCOPE
1.1 These practices cover the following five tests:
1.1.1 Practice A— Oxalic Acid Etch Test for Classification of Etch Structures of Austenitic Stainless Steels (Sections 3 to 7, inclusive),
1.1.2 Practice B—Ferric Sulfate-Sulfuric Acid Test for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels (Sections 8 to 14, inclusive),
1.1.3 Practice C—Nitric Acid Test for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels (Sections 15 to 21, inclusive),
1.1.4 Practice E—Copper-Copper Sulfate-Sulfuric Acid Test for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels (Sections 22 to 31, inclusive), and
1.1.5 Practice F—Copper-Copper Sulfate-50% Sulfuric Acid Test for Detecting Susceptibility to Intergranular Attack in Molybdenum-Bearing Cast Austenitic Stainless Steels (Sections 32 to 38, inclusive).
1.2 The following factors govern the application of these practices:
1.2.1 Susceptibility to intergranular attack associated with the precipitation of chromium carbides is readily detected in all six tests.
1.2.2 Sigma phase in wrought chromium-nickel-molybdenum steels, which may or may not be visible in the microstructure, can result in high corrosion rates only in nitric acid.
1.2.3 Sigma phase in titanium or columbium stabilized alloys and cast molybdenum bearing stainless alloys, which may or may not be visible in the microstructure, can result in high corrosion rates in both the nitric acid and ferric sulfate-sulfuric acid solutions.
1.3 The oxalic acid etch test is a rapid method of identifying, by simple etching, those specimens of certain stainless steel grades which are essentially free of susceptibility to intergranular attack associated with chromium carbide precipitates. These specimens will have low corrosion rates in certain corrosion tests and therefore can be eliminated (screened) from testing as "acceptable."
1.4 The ferric sulfate-sulfuric acid test, the copper-copper sulfate-50% sulfuric acid test, and the nitric acid test are based on weight loss determinations and, thus, provide a quantitative measure of the relative performance of specimens evaluated. In contrast, the copper-copper sulfate-16% sulfuric acid test is based on visual examination of bend specimens and, therefore, classifies the specimens only as acceptable or non-acceptable.
1.5 In most cases either the 24-h copper-copper sulfate-16% sulfuric acid test or the 120-h ferric sulfate-sulfuric acid test, combined with the oxalic acid etch test, will provide the required information in the shortest time. All stainless grades listed in the accompanying table may be evaluated in these combinations of screening and corrosion tests, except those specimens of molybdenum-bearing grades (for example 316, 316L, 317, and 317L), which represent steel intended for use in nitric acid environments.
1.6 The 240-h nitric acid test must be applied to stabilized and molybdenum-bearing grades intended for service in nitric acid and to all stainless steel grades which might be subject to end grain corrosion in nitric acid service.
1.7 Only those stainless steel grades are listed in Table 1 for which data on the application of the oxalic acid etch test and on their performance in various quantitative evaluation tests are available.
1.8 Extensive test results on various types of stainless steels evaluated by these practices have been published in Ref (1).
1.9 The values stated in SI units are to be regarded as standard. The inch-pound equivalents are in parentheses and may be approximate.
1.10 This standard does not purport to address all of the safety problems, 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. (Specific precautionary statements are given in 5.6, 11.1.1, ...
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or
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Designation: A 262 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
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Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practices for
Detecting Susceptibility to Intergranular Attack in Austenitic
1
Stainless Steels
This standard is issued under the fixed designation A 262; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope corrosion tests and therefore can be eliminated (screened) from
testing as “acceptable.”
1.1 These practices cover the following five tests:
1.4 The ferric sulfate-sulfuric acid test, the copper-copper
1.1.1 Practice A—Oxalic Acid Etch Test for Classification
sulfate-50 % sulfuric acid test, and the nitric acid test are based
of Etch Structures of Austenitic Stainless Steels (Sections 3 to
on weight loss determinations and, thus, provide a quantitative
7, inclusive),
measure of the relative performance of specimens evaluated. In
1.1.2 Practice B—Ferric Sulfate-Sulfuric Acid Test for
contrast, the copper-copper sulfate-16 % sulfuric acid test is
Detecting Susceptibility to Intergranular Attack in Austenitic
based on visual examination of bend specimens and, therefore,
Stainless Steels (Sections 8 to 14, inclusive),
classifies the specimens only as acceptable or non-acceptable.
1.1.3 Practice C—Nitric Acid Test for Detecting Suscepti-
1.5 In most cases either the 24-h copper-copper sulfate-
bility to Intergranular Attack in Austenitic Stainless Steels
16 % sulfuric acid test or the 120-h ferric sulfate-sulfuric acid
(Sections 15 to 21, inclusive),
test, combined with the oxalic acid etch test, will provide the
1.1.4 Practice E—Copper-Copper Sulfate-Sulfuric Acid
required information in the shortest time. All stainless grades
Test for Detecting Susceptibility to Intergranular Attack in
listed in the accompanying table may be evaluated in these
Austenitic Stainless Steels (Sections 22 to 31, inclusive), and
combinations of screening and corrosion tests, except those
1.1.5 Practice F—Copper-Copper Sulfate-50 % Sulfuric
specimens of molybdenum-bearing grades (for example 316,
Acid Test for Detecting Susceptibility to Intergranular Attack
316L, 317, and 317L), which represent steel intended for use in
in Molybdenum-Bearing Cast Austenitic Stainless Steels (Sec-
nitric acid environments.
tions 32 to 38, inclusive).
1.6 The 240-h nitric acid test must be applied to stabilized
1.2 The following factors govern the application of these
and molybdenum-bearing grades intended for service in nitric
practices:
acid and to all stainless steel grades which might be subject to
1.2.1 Susceptibility to intergranular attack associated with
end grain corrosion in nitric acid service.
the precipitation of chromium carbides is readily detected in all
1.7 Only those stainless steel grades are listed in Table 1 for
six tests.
which data on the application of the oxalic acid etch test and on
1.2.2 Sigma phase in wrought chromium-nickel-
their performance in various quantitative evaluation tests are
molybdenum steels, which may or may not be visible in the
available.
microstructure, can result in high corrosion rates only in nitric
1.8 Extensive test results on various types of stainless steels
acid.
2
evaluated by these practices have been published in Ref (1).
1.2.3 Sigma phase in titanium or columbium stabilized
1.9 The values stated in SI units are to be regarded as
alloys and cast molybdenum bearing stainless alloys, which
standard. The inch-pound equivalents are in parentheses and
may or may not be visible in the microstructure, can result in
may be approximate.
high corrosion rates in both the nitric acid and ferric sulfate-
1.10 This standard does not purport to address all of the
sulfuric acid solutions.
safety problems, if any, associated with its use. It is the
1.3 The oxalic acid etch test is a rapid method of identify-
responsibility of the user of this standard to establish appro-
ing, by simple etching, those specimens of certain stainless
priate safety and health practices and determine the applica-
steel grades which are essentially free of susceptibility to
bility of regulatory limitations prior to use. (Specific precau-
intergranular attack associated with chromium carbide precipi-
tionary statements are given in 5.6, 11.1.1, 11.1.9, and 35.1.)
tates. These specimens will have low corrosion rates in certain
2. Referenced Documents
1
2.1 ASTM Standards:
These practices are under the jurisdiction of ASTM Committee A-1 on Steel,
Stainless
...
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