ASTM A262-02ae3

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Designation: A 262 – 02a
Standard Practices for
Detecting Susceptibility to Intergranular Attack in Austenitic
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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.
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e NOTE—Table 1 was editorially corrected in August 2004.
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e NOTE—Section 30.1.5.1 was editorially corrected in January 2005.
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e NOTE—Sections 1.5 and 7.4 were editorially corrected in July 2005.
1. Scope* may or may not be visible in the microstructure, can result in
high corrosion rates in both the nitric acid and ferric sulfate-
1.1 These practices cover the following five tests:
–sulfuric acid solutions.
1.1.1 Practice A—Oxalic Acid Etch Test for Classification
1.3 The oxalic acid etch test is a rapid method of identify-
of Etch Structures of Austenitic Stainless Steels (Sections 3 to
ing, by simple etching, those specimens of certain stainless
7, inclusive),
steel grades that are essentially free of susceptibility to
1.1.2 Practice B—Ferric Sulfate–Sulfuric Acid Test for
intergranular attack associated with chromium carbide precipi-
Detecting Susceptibility to Intergranular Attack in Austenitic
tates. These specimens will have low corrosion rates in certain
Stainless Steels (Sections 8 to 14, inclusive),
corrosion tests and therefore can be eliminated (screened) from
1.1.3 Practice C—Nitric Acid Test for Detecting Suscepti-
testing as “acceptable.”
bility to Intergranular Attack in Austenitic Stainless Steels
1.4 The ferric sulfate–sulfuric acid test, the copper–copper
(Sections 15 to 21, inclusive),
sulfate–50 %sulfuricacidtest,andthenitricacidtestarebased
1.1.4 Practice E—Copper–Copper Sulfate–Sulfuric Acid
on weight loss determinations and, thus, provide a quantitative
Test for Detecting Susceptibility to Intergranular Attack in
measureoftherelativeperformanceofspecimensevaluated.In
Austenitic Stainless Steels (Sections 22 to 31, inclusive), and
contrast, the copper–copper sulfate–16 % sulfuric acid test is
1.1.5 Practice F—Copper–Copper Sulfate–50 % Sulfuric
based on visual examination of bend specimens and, therefore,
Acid Test for Detecting Susceptibility to Intergranular Attack
classifies the specimens only as acceptable or nonacceptable.
in Molybdenum-Bearing CastAustenitic Stainless Steels (Sec-
1.5 In most cases either the 15-h copper–copper sul-
tions 32 to 38, inclusive).
fate–16 % sulfuric acid test or the 120-h ferric sulfate–sulfuric
1.2 The following factors govern the application of these
acid test, combined with the oxalic acid etch test, will provide
practices:
the required information in the shortest time. All stainless
1.2.1 Susceptibility to intergranular attack associated with
grades listed in the accompanying table may be evaluated in
theprecipitationofchromiumcarbidesisreadilydetectedinall
these combinations of screening and corrosion tests, except
six tests.
those specimens of molybdenum-bearing grades (for example
1.2.2 Sigma phase in wrought chromium-nickel-
316, 316L, 317, and 317L), which represent steel intended for
molybdenum steels, which may or may not be visible in the
use in nitric acid environments.
microstructure, can result in high corrosion rates only in nitric
1.6 The 240-h nitric acid test must be applied to stabilized
acid.
and molybdenum-bearing grades intended for service in nitric
1.2.3 Sigma phase in titanium or columbium stabilized
acidandtoallstainlesssteelgradesthatmightbesubjecttoend
alloys and cast molybdenum-bearing stainless alloys, which
grain corrosion in nitric acid service.
1.7 Only those stainless steel grades are listed in Table 1 for
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These practices are under the jurisdiction of ASTM Committee A01 on Steel,
whichdataontheapplicationoftheoxalicacidetchtestandon
Stainless Steel and RelatedAlloys and are the direct responsibility of Subcommittee
their performance in various quantitative evaluation tests are
A01.14 on Methods of Corrosion Testing.
available.
Current edition approved Nov. 10, 2002. Published December 2002. Originally
approved in 1943. Last previous edition approved in 2002 as A 262 – 02.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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A 262 – 02a
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1.8 Extensive test results on various types of stainless steels Corrosion Test in Media Containing Sulfuric Acid
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evaluated by these practices have been published
...