ASTM G123-00(2022)e1

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.
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Designation:G123 −00 (Reapproved 2022)
Standard Test Method for
Evaluating Stress-Corrosion Cracking of Stainless Alloys
with Different Nickel Content in Boiling Acidified Sodium
Chloride Solution
This standard is issued under the fixed designation G123; 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.
ε NOTE—Replaced Terminology G15 with Terminology G193 and other editorial changes made throughout in Oct. 2022.
1. Scope responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This test method covers a procedure for conducting
mine the applicability of regulatory limitations prior to use.
stress-corrosion cracking tests in an acidified boiling sodium
For specific hazard statements, see Section 8.
chloride solution. This test method is performed in 25% (by
1.7 This international standard was developed in accor-
mass) sodium chloride acidified to pH 1.5 with phosphoric
dance with internationally recognized principles on standard-
acid. This test method is concerned primarily with the test
ization established in the Decision on Principles for the
solutionandglassware,althoughaspecificstyleofU-bendtest
Development of International Standards, Guides and Recom-
specimen is suggested.
mendations issued by the World Trade Organization Technical
1.2 This test method is designed to provide better correla-
Barriers to Trade (TBT) Committee.
tion with chemical process industry experience for stainless
steels than the more severe boiling magnesium chloride test of 2. Referenced Documents
Practice G36. Some stainless steels which have provided 2
2.1 ASTM Standards:
satisfactory service in many environments readily crack in
D1193Specification for Reagent Water
Practice G36, but have not cracked during interlaboratory
E8Test Methods for Tension Testing of Metallic Materials
testing(seeSection12)usingthissodiumchloridetestmethod.
[Metric] E0008_E0008M
1.3 Thisboilingsodiumchloridetestmethodwasusedinan E691Practice for Conducting an Interlaboratory Study to
interlaboratory test program to evaluate wrought stainless Determine the Precision of a Test Method
steels, including duplex (ferrite-austenite) stainless and an G16Guide for Applying Statistics to Analysis of Corrosion
alloywithuptoabout33%nickel.Itmayalsobeemployedto Data
evaluate these types of materials in the cast or welded G30 Practice for Making and Using U-Bend Stress-
conditions. Corrosion Test Specimens
G36Practice for Evaluating Stress-Corrosion-Cracking Re-
1.4 This test method detects major effects of composition,
sistance of Metals and Alloys in a Boiling Magnesium
heat treatment, microstructure, and stress on the susceptibility
Chloride Solution
of materials to chloride stress-corrosion cracking. Small dif-
G49Practice for Preparation and Use of Direct Tension
ferencesbetweensamplessuchasheat-to-heatvariationsofthe
Stress-Corrosion Test Specimens
same grade are not likely to be detected.
G107Guide for Formats for Collection and Compilation of
1.5 The values stated in SI units are to be regarded as
Corrosion Data for Metals for Computerized Database
standard. The values given in parentheses after SI units are
Input
providedforinformationonlyandarenotconsideredstandard.
G193Terminology and Acronyms Relating to Corrosion
1.6 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Definitions—For definitions of corrosion-related terms
used in this test method, see Terminology G193.
This test method 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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2022. Published October 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin1994.Lastpreviouseditionapprovedin2015asG123–00(2015).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0123-00R22E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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G123−00 (2022)
4. Summary of Test Method 6. Apparatus
4.1 Asolutionof25%sodiumchloride(by mass)inreagent 6.1 TheglasswareusedforthistestmethodisshowninFig.
water is mixed, and the pH is adjusted to 1.5 with phosphoric 1 and is as follows:
acid. The solution is boiled and U-bends (or other stressed 6.1.1 Flask—1000 mL Erlenmeyer flask with a 45/50
specimens) are exposed in fresh solution for successive one- ground-glass joint.
week periods. 6.1.2 Condenser, a four-bulbAllihn condenser with a 45/50
ground-glass joint (water-cooled joint suggested), a water
4.2 The test may be continued for as many weeks as
jacket at least 20 cm (8 in.) long and a 1cm to 2.5 cm (0.4in.
necessary, but six weeks (about 1000 h) or less are expected to
to 0.95in.) long drip tip is used. (Modified Allihn condensers
be sufficient to crack susceptible materials. Longer exposures
with no drip tip and condensers with longer drip tips may
provide greater assurance of resistance for those materials
produce different results. These alternate Allihn condenser
which do not crack.
designs may be used if control samples of susceptible (for
4.3 It is recommended that samples of a susceptible
example, UNS S31600) and resistant (for example, UNS
material, for example, UNS S30400 or S31600 (Type 304 or
N08020) materials are included in the study.)
Type316stainless,respectively),beincludedasacontrolwhen
6.1.3 Hot Plate, capable of maintaining the solution at its
more resistant materials are evaluated.
boiling point.
5. Significance and Use
7. Reagents
5.1 Thistestmethodisdesignedtocomparealloysandmay
7.1 Purity of Reagents—Reagent grade chemicals shall be
be used as one method of screening materials prior to service.
used in all tests. Unless otherwise indicated, it is intended that
In general, this test method is more useful for stainless steels
than the boiling magnesium chloride test of Practice G36. The
boiling magnesium chloride test cracks materials with the
nickel levels found in relatively resistant austenitic and duplex
stainless steels, thus making comparisons and evaluations for
many service environments difficult.
5.2 This test method is intended to simulate cracking in
water, especially cooling waters that contain chloride. It is not
intended to simulate cracking that occurs at high temperatures
(greater than 200°C or 390°F) with chloride or hydroxide.
NOTE 1—The degree of cracking resistance found in full-immersion
testsmaynotbeindicativeofthatforsomeserviceconditionscomprising
exposure to the water-line or in the vapor phase where chlorides may
concentrate.
5.3 Correlation with service experience should be obtained
when possible. Different chloride environments may rank
materials in a different order.
5.4 In interlaboratory testing, this test method cracked
annealed UNS S30400 and S31600 but not more resistant
materials, such as annealed duplex stainless steels or higher
nickelalloys,forexample,UNSN08020(forexample20Cb-3
stainless).Thesemoreresistantmaterialsareexpectedtocrack
when exposed to Practice G36 as U-bends. Materials which
withstand this sodium chloride test for a longer period than
UNS S30400 or S31600 may be candidates for more severe
service applications.
5.5 The repeatability and reproducibility data from Section
12 and Appendix X1 must be considered prior to use. Inter-
laboratory variation in results may be expected as occurs with
many corrosion tests. Acceptance criteria are not part of this
test method and if needed are to be negotiated by the user and
the producer.
20Cb-3 is a registered trademark of CarpenterTechnology Corp., Reading, PA. FIG. 1Apparatus Used for Stress-Corrosion Cracking Test
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G123−00 (2022)
all reagents shall conform to the specifications of the Commit- 9.4 Aminimumoffourreplicates(twoperflask)isrequired
tee onAnalytical Reagents of theAmerican Chemical Society, because of the variability typical in stress-corrosion testing.
where such specifications are available. Other grades may be
9.5 Methods of fabricating U-bend specimens are provided
used provided it is first ascertained that the reagent is of
inAnnexA1.TheseproceduresarebasedonPracticeG30,but
sufficiently high purity to permit its use without affecting
in addition provide a specimen that fits through a 45/50
results.
ground-glass joint. Assurance that the legs are stressed suffi-
7.2 Purity of Water—Solutions shall be made with water of ciently by the bolt is also provided.
purityconformingtoatleastTypeIVreagentwaterasspecified 9.5.1 Other methods of producing U-bends described in
in Specification D1193 (except that for this method limits for Practice G30 may be used; however, during exposure the
chlorides and sodium may be ignored). U-bendsmustbe(1)intheplasticrangeand(2)stressedtothe
maximum applied tensile load experienced during fabrication.
7.3 Sodium Chloride (NaCl)—Asolution of 25% NaCl (by
The same method must be used to fabricate all the U-bends in
mass) acidified to pH 1.5 with phosphoric acid (H PO)is
3 4
a given study.
used. The solution may be prepared by adding 750 g H O
9.5.2 The bolt, nut, and flat washer must be made of a
(750mL) to 250 g NaCl, and adjusting to pH 1.5 with H PO .
3 4
material resistant to general corrosion, pitting, and stress
Varying quantities of solution may be prepared and larger
corrosion cracking in the environment. UNS N10276 (Alloy
amounts may be stored indefinitely in appropriate glassware.
C-276) is recommended because some other materials (for
The pH must be determined prior to each use.
example, titanium or UNS N06600 [Alloy 600]) may be
attacked resulting in an increase in solution pH.
8. Hazards
9.5.3 The metallic fastener must be electrically isolated
8.1 Normal precautions for handling boiling liquid should
from the specimen by a rigid shoulder washer (that is, zirconia
be observed.
oranothermaterialthatwillnotbecompressedduringthetest).
8.2 All heating or boiling of the NaCl solution should be
9.5.4 Theextendedendoftheboltmayrequirecuttingtofit
done in an area where personnel are not likely to accidentally
into the test vessel.
bump the flask. A hooded area is preferred.
10. Procedure
8.3 Minimum personal protective equipment for handling
10.1 Stress the specimens, examine at 20×, and replace any
boiling sodium chloride should include safety glasses or
specimens with cracks or other defects.
goggles, face shield, laboratory coat, and rubber gloves.
(Warning—U-bends (and other highly stressed test speci-
NOTE 2—The direction and intensity of the incident light may affect
mens) may be susceptible to high rates of crack propagation
crack detection during the 20× examination.
and a specimen containing more than one crack may splinter
10.2 Degrease in a halogen-free solvent or laboratory
into two or more pieces. This may also occur due to a cracked
detergent, rinse as necessary, and dry. It is best practice to
restraining bolt. Due to the highly stressed condition in a
stress the specimens immediately before the beginning of the
U-bendspecimen,thesepiecesmayleavethespecimenathigh
test. Any storage of the specimens should be in a clean
velocity and can be dangerous.)
enclosure. A desiccant such as silica gel may be used. The
specific level of relative humidity is not important for the
9. Test Specimens
alloys of interest.
9.1 U-bends are preferred but other stress corrosion crack-
10.3 Place duplicate specimens in each 1000mL Erlen-
ing specimens may be used with this test solution. The
meyerflask.Duplicateflasks(fourspecimens)arenecessaryto
specimen style chosen should provide sufficient stress to crack
evaluate a given sample of the specific material, material
less resistant materials (for example, UNS S30400 or S31600)
condition,etc.(Thespecimensmaybeplacedintheflasksafter
in1000horless).(SeeAnnexA1.)Regardlessofthespecimen
the solution has been added, if convenient.)
style, it is recommended that UNS S30400 or UNS S31600, or
both, be included as controls. 10.4 The specimens in each flask must be kept separate and
completely submerged. Tight crevices between the stressed
9.2 The test specimen must be thick enough so that the
(bend) area and any means of specimen support should be
applied stress does not cause mechanical rupture of less
avoided. The stressed area should be free from direct contact
resistant materials if the cross section is reduced by pitting or
with heated surfaces. Specimens may be supported on glass
general corrosion.
rods or tubes or by glass fixtures.
9.3 The size of alternate specimens (other than those in
10.5 Drop boiling chips into the flasks.
AnnexA1) must allow a solution volume to specimen surface
2 2
area ratio of at least 5:1 mL/cm (33 mL/in. ). 10.6 Add 600 mL of 25% NaCl solution, pH 1.5, to each
flask. When each flask contains two U-bends as described in
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not The sole source of supply of amphoteric alundum granules known to the
listed by the American Chemical Society, see Analar Standards for Laboratory committee at this time is Hengar Co., Philadelphia, PA. If you are aware of
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia alternative suppliers, please provide this information to ASTM International
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, Headquarters.Your comments will receive careful consideration at a meeting of the
MD. responsible technical committee, which you may attend.
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G123−00 (2022)
AnnexA1, the solution volume to sample surface area ratio is 11. Report
2 2
5:1 mL/cm (33 mL/in. ).
11.1 Reportthetypeofspecimenused,methodofspecimen
fabrication, times to cracking (including maximum time with-
10.7 Placetheflasksonahotplateandinsertthecondenser.
out cracks), location of cracks, final pH of each exposure, and
Begin recording the test duration when the solution begins
detailsregardingtheAllihncondenserdriptip.Notewhetheror
boiling. The boiling point during interlaboratory testing was
not metallographic techniques or additional bending of the
106°C to 110°C (223°F to 230°F).
specimen(see10.13)wereemployed.Electronicdataexchange
10.8 After one week remove the flask from the hot plate,
canbefacilitatedbyusingthefieldssuggestedinAppendixX2
determinethefinalpHofthesolutionatroomtemperature,and
(excerpted from Guide G107).
discard the remaining solution. A final pH over about 2.5
11.2 Data for resistant materials shall be accompanied by
suggests that general corrosion or pitting of the specimen or
data for at least four susceptible control specimens; for
fastening device has occurred.ApH at this level is expected to
example, UNS S30400 or UNS S31600.
reduce the test severity and may delay or preclude failures of
UNS S31600. More rapid cracking of UNS S31600 appears
12. Precision and Bias
likely with a final pH of about 2 or less.
12.1 Precision—Variability occurred in both repeatability
and reproducibility for time-to-fail data developed using UNS
10.9 Rinse and dry the specimens. Examine the bend area,
legs,andareaadjacenttothecrevice(atthefastener)at20×for S30400 and S31600 in an interlaboratory test program (Ap-
pendix X1). Such variability is typical in time-to-fail data for
cracking. See Note 3. Record location of cracks. Additional
exposures or metallographic evaluation may be used to deter- stress-corrosion cracking tests, and is expected to preclude
detection of small differences between samples.
mine if questionable indications are, in fact, stress-corrosion
12.1.1 Histograms of the time-to-crack for UNS S30400
cracks.
and S31600 tested in accordance with this test method appear
NOTE 3—Any cracking at the fastener is very likely due to residual
in Appendix X1 along with data from each laboratory. The
stressesandmoreaggressivesolutionwhichmaybeformedincrevices.If
time-to-crack values in Appendix X1 are not necessarily the
crevices are expected in service (due to design of service equipment or
maximumorminimumvalueswhichcouldbeobtainedinother
deposits), a U-bend specimen employing a crevice on the bend may be
evaluated.
testing.
12.1.2 EveryspecimenofUNSS30400andS31600cracked
10.10 Periodic removal of the specimens from the solution
within the 1000h interlaboratory test duration while no crack-
may be necessary during the first week to determine the time
ing occurred for more resistant materials, UNS S32550 (Fer-
whencracksfirstappear.Removalofthespecimensisexpected
ralium Alloy 225) and N08020.
to disturb local corrosion cells and may influence test results.
12.1.3 It has been observed in stress-corrosion tests of
All specimens in a given test program should have the same
various metal-alloy systems that the precision is best for tests
removal/examination schedule. When the time-to-crack is
of specimens that have either a very low probability of
recorded, the test duration at the previous examination (no
stress-corrosioncracking(few,ifany,failuresintheprescribed
cracks) should also be noted.
test duration) or a high probability (short failure times). The
10.11 Expose for additional one-week periods as necessary.
precision is least for groups of test specimens with an inter-
Fresh solution must be used for each exposure and the initial
mediate probability. This was observed in the interlaboratory
and final pH (at room temperature) must be recorded weekly.
test program. There were no failures of the more resistant
See 10.8 regarding the effect of the final pH.
materials (UNS S32550 and UNS N08020), generally rapid
failure of the least resistant material (UNS S30400, see Fig.
10.12 After the final 20× examination (following the last
X1.3), and greater variation in failure times for the material
test period) remove the fastener and examine the crevice areas
expected to have intermediate resistance (UNS S31600, see
at 20× for cracking.
Fig. X1.4).
10.13 A final examination for cracks may be performed by
12.1.4 Reproducibility between laboratories
...