ASTM F2078-07
(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.
Some of the terms are defined in other terminology standards, which 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. These definitions are published to encourage uniformity of terminology in product specifications.
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Designation:F2078–07
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 baking—heating to a temperature at least 50°F below the
tempering or aging temperature of the metal or alloy to
1.1 This terminology covers the principal terms, abbrevia-
remove hydrogen before embrittlement occurs by the forma-
tions, and symbols relating to mechanical methods for hydro-
tion of microcracks.
gen embrittlement testing. These definitions are published to
encourage uniformity of terminology in product specifications.
DISCUSSION—No metallurgical changes take place as a result of
baking. (A 941)
2. Referenced Documents
2 brittle—the inability of a material to deform plastically before
2.1 ASTM Standards:
fracturing.
A 941 Terminology Relating to Steel, Stainless Steel, Re-
crackstrength—themaximumvalueofthenominalstressthat
lated Alloys, and Ferroalloys
a cracked specimen is capable of sustaining. (E 1823)
E6 Terminology Relating to Methods of Mechanical Test-
ductile—the ability of a material to deform plastically before
ing
fracturing. (E6)
E8 Test Methods for Tension Testing of Metallic Materials
embrittle—see embrittlement.
E 1823 Terminology Relating to Fatigue and Fracture Test-
embrittlement—the severe loss of ductility or toughness, or
ing
both, of a material, usually a metal or alloy. (G15)
F 1624 Test Method for Measurement of Hydrogen Em-
environmental hydrogen embirttlement (EHE)—generally
brittlement Threshold in Steel by the Incremental Step
caused by hydrogen introduced into the steel from the
Loading Technique
environment after exposure to an externally applied stress.
G15 Terminology Relating to Corrosion and Corrosion
Testing
DISCUSSION—Embrittlement as a result of hydrogen introduced into
steelfromexternalsourceswhileunderstress.Testsareconductedinan
3. Significance and Use
environment. (STP 962)
DISCUSSION—Foundinplatedpartsthatcathodicallyprotectthemetal
3.1 The terms used in describing hydrogen embrittlement
from corroding. Generates hydrogen at the surface of the metal.
have precise definitions. The terminology and its proper usage
Produces a clean, intergranular fracture surface. Not reversible. (The
must be completely understood to communicate and transfer
subtle differences between IHE and EHE are detailed inAppendix X1.)
information adequately within the field.
(STP 543)
3.2 Some of the terms are defined in other terminology
standards, which are respectively identified in parentheses environmentally assisted cracking (EAC)—see stress cor-
following the definition. rosion cracking.
fracture strength—the normal stress at the beginning of
4. Terminology
fracture.
4.1 Definitions:
gaseous hydrogen embrittlement (GHE)—a distinct form of
EHE caused by the presence of external sources of high
pressure hydrogen gas; cracking initiates on the outer
1
This terminology standard is under the jurisdiction of ASTM Committee F07
surface.
on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.04
heat treatment—heating to a temperature that produces met-
on Hydrogen Embrittlement.
Current edition approved Dec. 15, 2007. Published January 2008. Originally
allurgical changes in the steel that alter the mechanical
approved in 2001. Last previous edition approved in 2001 as F 2078–01.
properties and microstructure of the metal. (A 941)
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
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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F2078–07
hydrogen-assistedstresscracking(HASC)—crackgrowthas (E 1823)
a result of the presence of hydrogen; it can be either IHE or susceptibility to hydrogen embrittlement—is a material
EHE and sometimes is referred to as hydrogen stress property that is measured by the threshold stress intensity
cracking (HSC). parameter for hydrogen induced stress cracking, K ,K ,
Iscc IHE
hydrogen embrittlement—a permanent loss of ductility in a or K , which is a function of hardness and microstructure.
EHE
metal or alloy caused by absorption of hydrogen in combi- threshold (th)—a point, separating conditions that will pro-
nation with stress, either an externally applied or an internal duceagiveneffect,fromconditionsthatwillnotpro
...
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:F2078–01 Designation: F 2078 – 07
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
1.1 This 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.
2. Referenced Documents
2
2.1 ASTM Standards:
A 941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
E 6 Terminology Relating to Methods of Mechanical Testing
3
E 8Test Methods for Tension Testing of Metallic Materials
3
E812Test Method for Crack Strength of Slow Bend, Precracked Charpy Specimens of High-Strength Metallic Materials Test
Methods for Tension Testing of Metallic Materials
E 1823 Terminology Relating to Fatigue and Fracture Testing
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 Some of the terms are defined in other terminology standards, which are respectively identified in parentheses following the
definition.
4. Terminology
4.1 Definitions:
baking—heatingtoatemperatureatleast50°Fbelowthetemperingoragingtemperatureofthemetaloralloytoremovehydrogen
before embrittlement occurs by the formation of microcracks.
DISCUSSION—No metallurgical changes take place as a result of baking. (A 941)
brittle—the inability of a material to deform plastically before fracturing.
crack strength—the maximum value of the nominal stress that a cracked specimen is capable of sustaining. (E 1823)
ductile—the ability of a material to deform plastically before fracturing. (E 6)
embrittle—to make brittle; that is, to lose ductility. —see embrittlement.
embrittlement—the loss of ductility or toughness of a metal or alloy. —the severe loss of ductility or toughness, or both, of a
material, usually a metal or alloy. (G 15)
environmental hydrogen embirttlement (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. (STP 962)
DISCUSSION—Found in plated parts that cathodically protect the metal from corroding. Generates hydrogen at the surface of the metal. Produces a
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 May 10, 2001. Published July 2001.
Current edition approved Dec. 15, 2007. Published January 2008. Originally approved in 2001. Last previous edition approved in 2001 as F 2078–01.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 01.01.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 ----------------------
F2078–07
clean, intergranular fracture surface. Not reversible. (The subtle differences between IHE and EHE are detailed in Appendix X1.) (STP 543)
environmentally assisted cracking (EAC)—generic, crack growth as a result of exposure to the environment. — see stress
corrosion cracking.
fracture strength—the load at the beginning of fracture during a tension test divided by the original cross-sectional area. —the
normal stress at the beginning of fracture.
gaseous hydrogen embrittlement (GHE)—a distinct form of EHE caused by the presence of external sources of high pressure
hydrogen gas; cracking initiates on the outer surface.
heat treatment—heating to a temperature that produces metallurgical ch
...
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