ASTM G142-98(2004)
(Test Method)Standard Test Method for Determination of Susceptibility of Metals to Embrittlement in Hydrogen Containing Environments at High Pressure, High Temperature, or Both
Standard Test Method for Determination of Susceptibility of Metals to Embrittlement in Hydrogen Containing Environments at High Pressure, High Temperature, or Both
SIGNIFICANCE AND USE
This test method provides a reliable prediction of the resistance or susceptibility, or both, to loss of material strength and ductility as a result of exposure to hydrogen-containing gaseous environments. This test method is applicable over a broad range of pressures, temperatures, and gaseous environments. The results from this test method can be used to evaluate the effects of material composition, processing, and heat treatment as well as the effects of changes in environment composition, temperature, and pressure. These results may or may not correlate with service experience for particular applications. Furthermore, this test method may not be suitable for the evaluation of high temperature hydrogen attack in steels unless suitable exposure time at the test conditions has taken place prior to the initiation of tensile testing to allow for the development of internal blistering, decarburization or cracking, or both.
SCOPE
1.1 This test method covers a procedure for determination of tensile properties of metals in high pressure or high temperature, or both, gaseous hydrogen-containing environments. It includes accommodations for the testing of either smooth or notched specimens.
1.2 This applies to all materials and product forms including, but not restricted to, wrought and cast materials.
1.3 The values stated in SI units are to be regarded as the standard.
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 and health practices and determine the applicability of regulatory limitations prior to use. See 6.1 for additional information.
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Designation:G142–98 (Reapproved 2004)
Standard Test Method for
Determination of Susceptibility of Metals to Embrittlement in
Hydrogen Containing Environments at High Pressure, High
Temperature, or Both
This standard is issued under the fixed designation G142; 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.
1. Scope Susceptibility of Metallic Materials to Environmentally
Assisted Cracking
1.1 This test method covers a procedure for determination
2.2 Military Standard:
of tensile properties of metals in high pressure or high
MIL-P-27201B Propellant, Hydrogen
temperature, or both, gaseous hydrogen-containing environ-
ments. It includes accommodations for the testing of either
3. Terminology
smooth or notched specimens.
3.1 Definitions:
1.2 This applies to all materials and product forms includ-
3.1.1 control test, n—a mechanical test conducted in an
ing, but not restricted to, wrought and cast materials.
environment that does not produce embrittlement of a test
1.3 The values stated in SI units are to be regarded as the
material.
standard.
3.1.2 hydrogen embrittlement, n—hydrogen induced crack-
1.4 This standard does not purport to address all of the
ing or severe loss of ductility caused by the presence of
safety concerns, if any, associated with its use. It is the
hydrogen in the metal.
responsibility of the user of this standard to establish appro-
3.1.3 Other definitions and terminology related to testing
priate safety and health practices and determine the applica-
can be found in Terminology G15.
bility of regulatory limitations prior to use. See 6.1 for
additional information.
4. Summary of Test Method
4.1 Specimens of selected materials are exposed to a gas-
2. Referenced Documents
2 eoushydrogencontainingenvironmentathighpressureorhigh
2.1 ASTM Standards:
temperature, or both, while being pulled to failure in uniaxial
D1193 Specification for Reagent Water
tension. The susceptibility to hydrogen embrittlement is evalu-
E4 Practices for Force Verification of Testing Machines
ated through the determination of standard mechanical prop-
E8 Test Methods for Tension Testing of Metallic Materials
erties in tension (that is, yield strength, ultimate tensile
E691 Practice for Conducting an Interlaboratory Study to
strength, notched tensile strength, reduction in area or elonga-
Determine the Precision of a Test Method
tion, or both). Comparison of these mechanical properties
G15 Terminology Relating to Corrosion and Corrosion
3 determined in a hydrogen-containing environment to those
Testing
determined in a non-embrittling environment (control test)
G111 Guide for Corrosion Tests in High Temperature or
providesageneralindexofsusceptibilitytocrackingversusthe
High Pressure Environment, or Both
material’s normal mechanical behavior.
G129 Practice for Slow Strain Rate Testing to Evaluate the
5. Significance and Use
5.1 This test method provides a reliable prediction of the
This test method is under the jurisdiction of ASTM Committee G01 on
resistance or susceptibility, or both, to loss of material strength
Corrosion of Metals and is the direct responsibility of Subcommittee G01.06 on
and ductility as a result of exposure to hydrogen-containing
Environmentally Assisted Cracking .
gaseous environments. This test method is applicable over a
Current edition approved May 1, 2004. Published May 2004. Originally
approved in 1996. Last previous edition approved in 1998 as G142 – 98. DOI: broad range of pressures, temperatures, and gaseous environ-
10.1520/G0142-98R04.
ments. The results from this test method can be used to
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
evaluate the effects of material composition, processing, and
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
Withdrawn. The last approved version of this historical standard is referenced Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
on www.astm.org. Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G142–98 (2004)
FIG. 1 Notched Tensile Strength (NTS) Ratio for Various Alloys in 35 to 69 MPa Gaseous Hydrogen versus Air Tested at Room
Temperature
heat treatment as well as the effects of changes in environment with high values of tensile ratios (environment versus a control
composition, temperature, and pressure. These results may or environment) should be used. Materials with low values of this
may not correlate with service experience for particular appli- parameter should be avoided.
cations. Furthermore, this test method may not be suitable for
6.2.2 Closure and Seal—To facilitate operation of the test
the evaluation of high temperature hydrogen attack in steels
cell and tension testing, the closure should provide for rapid
unless suitable exposure time at the test conditions has taken
opening and closing of the test cell and reliable sealing
place prior to the initiation of tensile testing to allow for the
capabilities for hydrogen. This can include either metallic or
developmentofinternalblistering,decarburizationorcracking,
non-metallic materials with high resistance to hydrogen em-
or both.
brittlement and degradation.
6.2.3 Gas Port(s)—The gas port should be designed to
6. Apparatus
promote flow and circulation of the gaseous test environments,
6.1 Since this test method is intended to be conducted at
inert gas purging and evacuation as required to produce the
high pressures and may also involve high temperatures, the
intended test environment. Usually two ports are used so that
apparatus must be constructed to safely contain the test
flow-through capabilities are attained to facilitate these func-
environment while being resistant to the embrittling effects of
tions.
hydrogen. Secondly, the test apparatus must be capable of
6.2.4 Electrical Feed-Throughs—If very high temperature
allowing introduction of the test gas, removal of air from the
conditions are required it may be advantageous to utilize an
test cell, and accurate performance of the tension test on the
internal heater to heat the test specimen and the gaseous
test specimen. In cases where the tests are conducted at
environment in the immediate vicinity of the specimen. There-
elevated temperatures, the apparatus must provide for heating
fore, a feed-through would be needed to reach an internal
of the specimen and the test environment in direct contact with
resistance or induction heater. These feed-throughs must also
the specimen.
provide electrical isolation from the test cell and internal
6.2 Fig. 2 shows a schematic representation of a typical test
fixtures, and maintain a seal to prevent leakage of the test
cell designed to conduct HP/HT gaseous hydrogen embrittle-
environment. If external heaters are used, no electric feed-
ment experiments. The typical components include:
throughs would be required for testing.
6.2.1 Metal Test Cell—The test cell should be constructed
6.2.5 Tensile Feed-Through(s)—To apply tensile loading to
from materials that have proven to have high resistance to
the test specimen it is necessary to have feed-through(s) which
hydrogen embrittlement under the conditions. A list of poten-
provide linear motion and transmission of loads from an
tial materials of construction is shown in Fig. 1. Materials
external source. Care must be taken to design such feed-
throughs to have low friction to minimize errors due to friction
R. D. Kane, “High Temperature and High Pressure,” Corrosion Tests and
losses when using externally applied loads. These are usually
Standards, Ed. Robert Baboian, ASTM, West Conshohocken, PA.
designed to incorporate thermoplastic or elastomeric materials,
Metals Handbook, Vol 9, Corrosion, 9th Edition, ASM International, Metals
Park, OH, 1987, p. 1104. or both. If elevated temperature tests are being conducted, then
G142–98 (2004)
6.2.7.2 Internal load cells which are either attached to the
pull rod or grip assembly inside of the autoclave or are
integrated into the pull rod.When using external load cells it is
important to correct load cell readings for frictional forces in
the pressure seal. Additionally, if non-pressure balanced pull
rods are used, compensation for pressure loading of the
specimen must be also performed.
6.2.8 Electric Resistance or Induction Heater(s)—Either
internal or external heaters can be used to obtain elevated
temperature. For lower temperatures, and when using test
environments containing reactive constituents in addition to
hydrogen, external heating of the test cell is typically more
convenient. At high temperatures, when using non-reactive or
hydrogen gas environments, an internal heater can be used to
heat only the test specimen and the gaseous environment in the
vicinity of the test specimen to limit power requirements and
problems with high temperature sealing and pressure contain-
ment.
6.2.9 Grips—Grips shall provide for efficient and accurate
transfer of load from the pull rods to the test specimen. Grips
should be designed to minimize compliance in the loading
system under the anticipated loads to pull the test specimen.
6.2.10 Loading Fixture—A fixture is used to react the load
used to pull the specimen. An internal fixture is shown
schematically in Fig. 2.
6.2.11 Testing Machines—Tension testing machines used
forconductingtestsaccordingtothistestmethodshallconform
to the requirements of Practices E4. The loads used in tests
shall be within the calibrated load ranges of the testing
machines in accordance with Practices E4.
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals and ultra
low oxygen gases (<1 ppm) shall be used in all tests unless the
test environment is derived from a field or plant environment.
If the test is to be conducted for aerospace propulsion appli-
FIG. 2 Hydrogen Tensions Test Autoclave for Various Alloys in
cations, the environment shall consist of hydrogen gas per
Hydrogen versus Air
MIL-P-27201B.
7.2 If water is to be added to any test environment, distilled
ordeionizedwaterconformingtoSpecificationD1193TypeIV
extreme care must be used in the selection of these materials to
shall be used.
alsoresistdeteriorationandlossofmechanicalpropertiesatthe
test temperature.
8. Test Environment
6.2.6 Pull Rod—Thepullrodworksincombinationwiththe
8.1 Test environments can consist of either field or plant
tensile feed-through to provide for loading of the test speci-
samples or be prepared in the laboratory from chemicals and
men. It is usually attached to a tensile testing machine on one
gases as indicated in Section 7.
end and the tension specimen on the other. It should be
8.2 When testing in hydrogen containing environments,
designed to have adequate cross-sectional area to minimize
susceptibility to hydrogen embrittlement typically increases
complianceintheloadingsystemundertheanticipatedloadsto
with decreasing oxygen content of the test environment.
be used. Also, to minimize frictional forces in the seal and
Therefore, strict procedures for deaeration shall be followed
promote sealing, it should be made with a highly polished
and periodically qualified for oxygen content as discussed in
surfaces [<0.25 µm (10 µin.) RMS]. It is possible to obtain pull
Sections 9 and 11.
rod systems that are pressure balanced so specimen loading
from the internal pressure in the test cell can be minimized. 8.3 For purposes of standardization, suggested standardized
6.2.7 Load Cell—Load cells for conducting high pressure pressuresforhydrogengastestingshallbe7MPa,35MPa,and
tensile tests may be two configurations: 69 MPa. However, for materials evaluation for specific appli-
6.2.7.1 External load cells which are attached to the pull rod cations, the test pressure should be equal to or greater than that
outside of the test cell, and which represents the service conditions.
G142–98 (2004)
9. Sampling
9.1 The procedure for sampling mill products is typically
covered in product or other specifications and is outside the
scope of this document.
9.2 Sampling of the test environment is recommended to
confirm that the test environment is in conformance with this
test method and attains the intended test conditions. Such
sampling shall be conducted immediately prior to and after
testing. The frequency of environmental sampling shall be as
required to cover applicable product, purchase or in-house
testingspecifications,orboth.Asaminimumrequirementtobe
in compliance with this test method, however, sampling of the
test environment shall be conducted at the start of testing and
againwhenanyelementofthetestprocedureortestsystemhas
been changed or modified.
10. Test Specimens
10.1 Tension specimens shall be used for evaluation of
hydrogen embrittlement.These specimens shall conform to the
dimensions and guidelines provided in Test Methods E8.
However, in some cases, the material size, configuration, and
form or the confines of various test cells may limit the actual
dimensions of the test specimen. In such cases, the specimen
geometry and dimensions shall be fully described.Take care to
only compare the results obtained from similar specimens.
10.2 For purposes of standardizing the evaluation of mate-
rials according to this test method, two standard test specimens
FIG. 3 Standard Tension Specimens (a) Smooth and (b) Notched
shall be used: standard smooth tension specimen, and standard
notched tensile specimen. The dimensions of these specimens
12. Test Procedure
are given in Fig. 3a and Fig. 3b.
12.1 Follow the basic guidelines for high pressure/high
10.3 Specimens shall be machined to have a minimal
temperature corrosion testing in Guide G111 where applicable.
amount of cold work on the gage or notch surfaces.Total metal
12.2 Measure the initial specimen dimensions. For smooth
removedinthelasttwopassesshallbelimitedtoatotalof0.05
tensile specimens, the dimensions measured are gage length
mmandhaveasurfacefinishof0.25µm(10µin.)orbetter.The
and diameter. For notched specimens, the dimensions are gage
method of final machining of the gage section should be by
and notch diameter.
grinding (not turning) to avoid localized grooves and cold
12.3 Degrease and clean the specimen. Once cleaned the
worked areas.
specimen shall not be handled with bare hands.
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