ASTM F2078-08
(Terminology)Standard Terminology Relating to Hydrogen Embrittlement Testing
Standard Terminology Relating to Hydrogen Embrittlement Testing
SIGNIFICANCE AND USE
p>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
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 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, abbrevia-
tions, and symbols relating to mechanical methods for hydro-
4. Terminology
gen embrittlement testing, which are present in more than one
4.1 Definitions:
of the standards under the jurisdiction of ASTM Committee
F07 onAerospace andAircraft.These definitions are published
baking—heatingtoatemperature,nottoexceed50°F(27.8°C)
to encourage uniformity of terminology in product specifica-
below the tempering or aging temperature of the metal or
tions.
alloy, in order to remove hydrogen before embrittlement
occurs by the formation of microcracks.
2. Referenced Documents
2 DISCUSSION—No metallurgical changes take place as a result of
2.1 ASTM Standards:
baking.
C 904 Terminology Relating to Chemical-Resistant Non-
metallic Materials
brittle—see brittleness.
D 4848 Terminology Related to Force, Deformation and brittleness—the tendency of a material to break at a very low
Related Properties of Textiles
strain, elongation, or deflection, and to exhibit a clean
E6 Terminology Relating to Methods of Mechanical Test- fracture surface with no indications of plastic deformation.
ing
(E 631)
E8 Test Methods for Tension Testing of Metallic Materials crack—line of fracture without complete separation. (F 109)
E 631 Terminology of Building Constructions
crackstrength—themaximumvalueofthenominalstressthat
E 1823 Terminology Relating to Fatigue and Fracture Test- a cracked specimen is capable of sustaining. (E 1823)
ing
ductile—see ductility.
F 109 Terminology Relating to Surface Imperfections on
ductility—the ability of a material to deform plastically before
Ceramics fracturing. (E6)
F 1624 Test Method for Measurement of Hydrogen Em-
embrittle—see embrittlement.
brittlement Threshold in Steel by the Incremental Step embrittlement—the severe loss of ductility or toughness, or
Loading Technique
both, of a material, usually a metal or alloy. (G15)
G15 Terminology Relating to Corrosion and Corrosion environmental hydrogen embrittlement (EHE)—hydrogen
Testing
embrittlement caused by hydrogen introduced into a steel/
metallic alloy from an environmental source coupled with
3. Significance and Use
stress either residual or externally applied.
3.1 The terms used in describing hydrogen embrittlement
DISCUSSION—Produces a clean intergranular fracture and is not
have precise definitions. The terminology and its proper usage
reversible. For the subtle differences between EHE and IHE, see Table
must be completely understood to communicate and transfer
X1.1.
information adequately within the field.
environmentally assisted cracking (EAC)—see stress cor-
rosion cracking.
1
This terminology standard is under the jurisdiction of ASTM Committee F07
fracture strength—the normal stress at the beginning of
on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.04
fracture.
on Hydrogen Embrittlement.
gaseous hydrogen embrittlement (GHE)—a distinct form of
CurrenteditionapprovedJuly1,2008.PublishedJuly2008.Originallyapproved
in 2001. Last previous edition approved in 2008 as F 2078–08.
EHE caused by the presence of external sources of high
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
pressure hydrogen gas; cracking initiates on the outer
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
surface.
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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F2078–08a
stress (G15). In essence the process of SCC and EAC are equivalent.
heat treatment—heating and cooling processes that produce
metallurgical changes in the metallic alloy which alter the
stress–intensity factor, K—the magnitude of the mathemati-
mechanical properties and microstructure of the metal.
cally ideal crack–tip stress field (stress field singularity) for
hydrogen-assistedstresscracking(HASC)—crackgrowthas
a particular mode in a homogeneous linear–elastic body.
aresultofthepresenceofhydrogen,whichcanbeeitherIHE
(E 1823)
or EHE and sometimes is referred to as hydrogen stress
DISCUSSION—K =for a Mode I (opening mode) lo
...
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:F2078–07 Designation: F 2078 – 08
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1This terminology covers the principal terms, abbreviations, and symbols relating to mechanical methods for hydrogen
embrittlement testing. These definitions are published to encourage uniformity of terminology in product specifications.
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:
A941Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys C 904 Terminology Relating to
Chemical-Resistant Nonmetallic Mate-
rials
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.
3.2Some of the 3.2 The terms are defined in other terminology standards, which are respectively identified in parentheses
following the definition.
4. Terminology
4.1 Definitions:
baking—heating to a temperature at least 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. (A941)
brittle—the inability of a material to deform plastically before fracturing. —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)
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 Dec.Feb. 15, 2007.2008. Published JanuaryMarch 2008. Originally approved in 2001. Last previous edition approved in 20012007 as
F 2078–017.
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
---------------------- Page: 1 ----------------------
F2078–08
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 embirittlement (EHE)— generally caused by hydrogen introduced into the steel from the environment
after exposure to an externally applied stress.
DISCUSSION—Embrittlement as a result of hydrogen introduced into steel from external sources while under stress. Tests are conducted in an
environment. —Embrittlement as a result of hydrogen introduced into steel from external sources while under stress. Tests are conducted in an
environment.Foundinplatedpartsthatcathodicallyprotectthem
...
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