ASTM G38-01(2013)

Standard Practice for Making and Using C-Ring Stress-Corrosion Test Specimens

SIGNIFICANCE AND USE
4.1 The C-ring is a versatile, economical specimen for quantitatively determining the susceptibility to stress-corrosion cracking of all types of alloys in a wide variety of product forms. It is particularly suitable for making transverse tests of tubing and rod and for making short-transverse tests of various products as illustrated for plate in Fig. 1.
SCOPE
1.1 This practice covers the essential features of the design and machining, and procedures for stressing, exposing, and inspecting C-ring type of stress-corrosion test specimens. An analysis is given of the state and distribution of stress in the C-ring.  
1.2 Specific considerations relating to the sampling process and to the selection of appropriate test environments are outside the scope of this practice.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
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.

General Information

• Status: Historical
• Publication Date: 30-Apr-2013
• ICS: 77.040.30 - Chemical analysis of metals
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.06 - Environmentally Assisted Cracking

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G38 − 01 (Reapproved 2013)
Standard Practice for
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Making and Using C-Ring Stress-Corrosion Test Specimens
ThisstandardisissuedunderthefixeddesignationG38;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope cracking of all types of alloys in a wide variety of product
forms. It is particularly suitable for making transverse tests of
1.1 This practice covers the essential features of the design
tubingandrodandformakingshort-transversetestsofvarious
and machining, and procedures for stressing, exposing, and
products as illustrated for plate in Fig. 1.
inspecting C-ring type of stress-corrosion test specimens. An
analysis is given of the state and distribution of stress in the
5. Sampling
C-ring.
5.1 Test specimens shall be taken from a location and with
1.2 Specific considerations relating to the sampling process
an orientation so that they adequately represent the material to
and to the selection of appropriate test environments are
be tested.
outside the scope of this practice.
5.2 In testing thick sections that have a directional grain
1.3 The values stated in SI units are to be regarded as
structure, it is essential that the C-ring be oriented in the
standard. The values given in parentheses are for information
section so that the direction of principal stress (parallel to the
only.
stressing bolt) is in the direction of minimum resistance to
1.4 This standard does not purport to address all of the
stress-corrosion cracking. For example, in the case of alumi-
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safety concerns, if any, associated with its use. It is the
numalloys (1), thisistheshort-transversedirectionrelativeto
responsibility of the user of this standard to establish appro-
the grain structure. If the ring is not so oriented it will tend to
priate safety and health practices and determine the applica-
crack off-center at a location where the stress is unknown.
bility of regulatory limitations prior to use.
6. Specimen Design
2. Referenced Documents
6.1 Sizes for C-rings may be varied over a wide range, but
2.1 NACE Document: 5
C-ringswithanoutsidediameterlessthanabout16mm( ⁄8in.)
NACE TM0177–96Laboratory Testing of Metals for Resis-
are not recommended because of increased difficulties in
tance to Sulfide Stress Cracking and Stress Corrosion
machining and decreased precision in stressing. The dimen-
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Cracking in H S Environments
2 sions of the ring can affect the stress state, and these consid-
erations are discussed in Section 7.Atypical shop drawing for
3. Summary of Practice
the manufacture of a C-ring is shown in Fig. 2.
3.1 This practice involves the preparation of and the quan-
titative stressing of a C-ring stress-corrosion test specimen by
7. Stress Considerations
application of a bending load. Characteristics of the stress
7.1 The stress of principal interest in the C-ring specimen is
system and the distribution of stresses are discussed. Guidance
the circumferential stress. It should be recognized that this
is given for methods of exposure and inspection.
stressisnotuniform (2, 3).First,thereisagradientthroughthe
thickness, varying from a maximum tension on one surface to
4. Significance and Use
amaximumcompressionontheoppositesurface.Secondly,the
4.1 The C-ring is a versatile, economical specimen for
stress varies around the circumference of the C-ring from zero
quantitativelydeterminingthesusceptibilitytostress-corrosion
at each bolt hole to a maximum at the middle of the arc
opposite the stressing bolt; the nominal stress is present only
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This practice is under the jurisdiction ofASTM Committee G01 on Corrosion
alongalineacrosstheringatthemiddleofthearc.Thus,when
of Metals and is the direct responsibility of Subcommittee G01.06 on Environmen-
the specimen is stressed by measuring the strain on the tension
tally Assisted Cracking.
surface of the C-ring, the strain gage should be positioned at
CurrenteditionapprovedMay1,2013.PublishedJuly2013.Originallyapproved
in 1973. Last previous edition approved in 2007 as G38-01 (2007). DOI:
10.1520/G0038-01R13.
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2
AvailablefromNationalAssociationofCorrosionEngineers(NACE),P.O.Box Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
218340, Houston, TX 77218–8340. this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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G38 − 01 (2013)
addition, the circumferential stress at the root of the notch will
be greater than the nominal stress and generally may be
expect
...