ASTM F2078-08a
(Terminology)Standard Terminology Relating to Hydrogen Embrittlement Testing
Standard Terminology Relating to Hydrogen Embrittlement Testing
SIGNIFICANCE AND USE
The terms used in describing hydrogen embrittlement have precise definitions. The terminology and its proper usage must be completely understood to communicate and transfer information adequately within the field.
The terms defined in other terminology standards, are respectively identified in parentheses following the definition.
SCOPE
1.1 This terminology covers the principal terms, abbreviations, and symbols relating to mechanical methods for hydrogen embrittlement testing, which are present in more than one of the standards under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft. These definitions are published to encourage uniformity of terminology in product specifications.
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Designation: F2078 − 08a
StandardTerminology Relating to
1
Hydrogen Embrittlement Testing
This standard is issued under the fixed designation F2078; 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 3.2 The terms defined in other terminology standards, are
respectively identified in parentheses following the definition.
1.1 This terminology covers the principal terms,
abbreviations, and symbols relating to mechanical methods for
4. Terminology
hydrogenembrittlementtesting,whicharepresentinmorethan
4.1 Definitions:
one of the standards under the jurisdiction of ASTM Commit-
baking—heatingtoatemperature,nottoexceed50°F(27.8°C)
tee F07 on Aerospace and Aircraft. These definitions are
below the tempering or aging temperature of the metal or
published to encourage uniformity of terminology in product
alloy, in order to remove hydrogen before embrittlement
specifications.
occurs by the formation of microcracks.
DISCUSSION—No metallurgical changes take place as a result of
2. Referenced Documents
baking.
2
2.1 ASTM Standards:
brittle—see brittleness.
C904 Terminology Relating to Chemical-Resistant Nonme-
brittleness—the tendency of a material to break at a very low
tallic Materials
strain, elongation, or deflection, and to exhibit a clean
D4848 Terminology Related to Force, Deformation and
fracture surface with no indications of plastic deformation.
Related Properties of Textiles
(E631)
E6 Terminology Relating to Methods of Mechanical Testing
E8 Test Methods for Tension Testing of Metallic Materials
crack—line of fracture without complete separation. (F109)
E631 Terminology of Building Constructions
crack strength—themaximumvalueofthenominalstressthat
E1823 TerminologyRelatingtoFatigueandFractureTesting
a cracked specimen is capable of sustaining. (E1823)
F109 Terminology Relating to Surface Imperfections on
Ceramics
ductile—see ductility.
F1624 Test Method for Measurement of Hydrogen Em-
ductility—the ability of a material to deform plastically before
brittlement Threshold in Steel by the Incremental Step
fracturing. (E6)
Loading Technique
G15 Terminology Relating to Corrosion and CorrosionTest-
embrittle—see embrittlement.
3
ing (Withdrawn 2010)
embrittlement—the severe loss of ductility or toughness, or
both, of a material, usually a metal or alloy. (G15)
3. Significance and Use
environmental hydrogen embrittlement (EHE)— hydrogen
3.1 The terms used in describing hydrogen embrittlement
embrittlement caused by hydrogen introduced into a steel/
have precise definitions. The terminology and its proper usage
metallic alloy from an environmental source coupled with
must be completely understood to communicate and transfer
stress either residual or externally applied.
information adequately within the field.
DISCUSSION—Produces a clean intergranular fracture and is not
reversible. For the subtle differences between EHE and IHE, see Table
X1.1.
1
This terminology standard is under the jurisdiction of ASTM Committee F07
on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.04 environmentally assisted cracking (EAC)— see stress cor-
on Hydrogen Embrittlement.
rosion cracking.
CurrenteditionapprovedJuly1,2008.PublishedJuly2008.Originallyapproved
in2001.Lastpreviouseditionapprovedin2008asF2078–08.DOI:10.1520/F2078-
fracture strength—the normal stress at the beginning of
08A.
fracture.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
gaseous hydrogen embrittlement (GHE)—a distinct form of
Standards volume information, refer to the standard’s Document Summary page on
EHE caused by the presence of external sources of high
the ASTM website.
3
pressure hydrogen gas; cracking initiates on the outer
The last approved version of this historical standard is referenced on
www.astm.org. surface.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2078 − 08a
heat treatment—heating and cooling processes that produce stress corrosion cracking (SCC)—a cracking process that
metallurgical changes in the metallic alloy which alter the requiresthesimultaneousactionofacorrodentandsustained
mechanical properties and microstructure of the metal. tensile stress.
DISCUSSION—This excludes corrosion-reduced sections that fail by
hydrogen-assisted stress cracking (HASC)— crack growth
fast fracture. It also excludes intercrystalline or transcrystalline
as a result of the presence of hydrogen, which
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:F2078–08 Designation: F 2078 – 08a
Standard Terminology Relating to
1
Hydrogen Embrittlement Testing
This standard is issued under the fixed designation F 2078; 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
1.1 This terminology covers the principal terms, abbreviations, and symbols relating to mechanical methods for hydrogen
embrittlement testing, which are present in more than one of the standards under the jurisdiction of ASTM Committee F07 on
Aerospace and Aircraft. These definitions are published to encourage uniformity of terminology in product specifications.
2. Referenced Documents
2
2.1 ASTM Standards:
C 904 Terminology Relating to Chemical-Resistant Nonmetallic Materials
D 4848 Terminology Related to Force, Deformation and Related Properties of Textiles
E 6 Terminology Relating to Methods of Mechanical Testing
E 8 Test Methods for Tension Testing of Metallic Materials
E 631 Terminology of Building Constructions
E 1823 Terminology Relating to Fatigue and Fracture Testing
F 109 Terminology Relating to Surface Imperfections on Ceramics
F 1624 Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading
Technique
G 15 Terminology Relating to Corrosion and Corrosion Testing
3. Significance and Use
3.1 The terms used in describing hydrogen embrittlement have precise definitions. The terminology and its proper usage must
be completely understood to communicate and transfer information adequately within the field.
3.2 The terms defined in other terminology standards, are respectively identified in parentheses following the definition.
4. Terminology
4.1 Definitions:
baking—heating to a temperature, not to exceed 50°F (27.8°C) below the tempering or aging temperature of the metal or alloy,
in order to remove hydrogen before embrittlement occurs by the formation of microcracks.
DISCUSSION—No metallurgical changes take place as a result of baking.
brittle—see brittleness .
brittleness—the tendency of a material to break at a very low strain, elongation, or deflection, and to exhibit a clean fracture
surface with no indications of plastic deformation. (E 631)
crack—line of fracture without complete separation. (F 109)
crack strength—the maximum value of the nominal stress that a cracked specimen is capable of sustaining. (E 1823)
ductile—see ductility .
ductility—the ability of a material to deform plastically before fracturing. (E 6)
embrittle—see embrittlement.
embrittlement—the severe loss of ductility or toughness, or both, of a material, usually a metal or alloy. (G 15)
environmental hydrogen embrittlement (EHE)— generally caused by hydrogen introduced into the steel from the environment
after exposure to an externally applied stress. — hydrogen embrittlement caused by hydrogen introduced into a steel/metallic
1
This terminology standard is under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.04 on
Hydrogen Embrittlement.
Current edition approved Feb. 15,July 1, 2008. Published MarchJuly 2008. Originally approved in 2001. Last previous edition approved in 20072008 as F 2078–078.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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F 2078 – 08a
alloy from an environmental source coupled with stress either residual or externally applied.
DISCUSSION—Embrittlement as a result of hydrogen introduced into steel from external sources while under stress. Tests are conducted in an
environment.Foundinplatedpartsthatcathodicallyprotectthemetalfromcorroding.Generateshydrogenatthesurfaceofthemetal.Producesaclean,
intergranular fracture surface and is not reversible. For the subtle differences between IHE and EHE see Table X1.1. (STP962) (STP543)
—Produces a clean intergranular fracture and is not reversible. For the subtle differences between EHE and IHE, see
Table X1.1.
environmentally assisted cracking (EAC)— see stress corrosion cracking.
fracture s
...
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