ASTM G58-85(2011)
(Practice)Standard Practice for Preparation of Stress-Corrosion Test Specimens for Weldments
Standard Practice for Preparation of Stress-Corrosion Test Specimens for Weldments
SIGNIFICANCE AND USE
The intent of this practice is to indicate standard welded specimens and welding procedures for evaluating the SCC characteristics of weldments in corrosive environments. The practice does not recommend the specific corrosive media that may be selected by the user depending upon the intent of his investigation. Specific corrosive media are included in Practices G 35, G 36, G 37, and G 44. Other environments can be used as required.
SCOPE
.
1.1 This practice covers procedures for the making and utilization of test specimens for the evaluation of weldments in stress-corrosion cracking (SCC) environments.
1.2 Test specimens are described in which (a) stresses are developed by the welding process only, (b) stresses are developed by an externally applied load in addition to the stresses due to welding, and (c) stresses are developed by an externally applied load only with residual welding stresses removed by annealing.
1.3 This practice is concerned only with the welded test specimen and not with the environmental aspects of stress-corrosion testing. Specific practices for the bending and loading of test specimens, as well as the stress considerations involved in preparation of C-rings, U-bend, bent-beam, and tension specimens are discussed in other ASTM standards.
1.4 The actual stress in test specimens removed from weldments is not precisely known because it depends upon the level of residual stress from the welding operation combined with the applied stress. A method for determining the magnitude and direction of residual stress which may be applicable to weldment is described in Test Method E837. The reproducibility of test results is highly dependent on the preparation of the weldment, the type of test specimen tested, and the evaluation criteria used. Sufficient replication should be employed to determine the level of inherent variability in the specific test results that is consistent with the objectives of the test program.
1.5 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. (For more specific safety hazards information, see Section 7.)
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Standards Content (Sample)
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Designation: G58 − 85(Reapproved 2011)
Standard Practice for
Preparation of Stress-Corrosion Test Specimens for
Weldments
ThisstandardisissuedunderthefixeddesignationG58;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers procedures for the making and
E8Test Methods for Tension Testing of Metallic Materials
utilizationoftestspecimensfortheevaluationofweldmentsin
E399Test Method for Linear-Elastic Plane-Strain Fracture
stress-corrosion cracking (SCC) environments.
Toughness K of Metallic Materials
Ic
1.2 Test specimens are described in which (a) stresses are
E837Test Method for Determining Residual Stresses by the
developed by the welding process only, (b) stresses are
Hole-Drilling Strain-Gage Method
developed by an externally applied load in addition to the
G1Practice for Preparing, Cleaning, and Evaluating Corro-
stresses due to welding, and (c) stresses are developed by an
sion Test Specimens
externally applied load only with residual welding stresses
G30 Practice for Making and Using U-Bend Stress-
removed by annealing.
Corrosion Test Specimens
G35Practice for Determining the Susceptibility of Stainless
1.3 This practice is concerned only with the welded test
Steels and Related Nickel-Chromium-Iron Alloys to
specimen and not with the environmental aspects of stress-
Stress-Corrosion Cracking in Polythionic Acids
corrosion testing. Specific practices for the bending and load-
G36Practice for Evaluating Stress-Corrosion-Cracking Re-
ing of test specimens, as well as the stress considerations
sistance of Metals and Alloys in a Boiling Magnesium
involved in preparation of C-rings, U-bend, bent-beam, and
Chloride Solution
tension specimens are discussed in other ASTM standards.
G37Practice for Use of Mattsson’s Solution of pH 7.2 to
1.4 The actual stress in test specimens removed from
Evaluate the Stress-Corrosion Cracking Susceptibility of
weldments is not precisely known because it depends upon the
Copper-Zinc Alloys
level of residual stress from the welding operation combined
G38 Practice for Making and Using C-Ring Stress-
with the applied stress. A method for determining the magni-
Corrosion Test Specimens
tudeanddirectionofresidualstresswhichmaybeapplicableto
G39Practice for Preparation and Use of Bent-Beam Stress-
weldment is described inTest Method E837.The reproducibil-
Corrosion Test Specimens
ity of test results is highly dependent on the preparation of the
G44PracticeforExposureofMetalsandAlloysbyAlternate
weldment, the type of test specimen tested, and the evaluation
Immersion in Neutral 3.5 % Sodium Chloride Solution
criteria used. Sufficient replication should be employed to
G49Practice for Preparation and Use of Direct Tension
determine the level of inherent variability in the specific test
Stress-Corrosion Test Specimens
resultsthatisconsistentwiththeobjectivesofthetestprogram.
3. Summary of Practice
1.5 This standard does not purport to address all of the
3.1 The following summarizes the test objectives that may
safety concerns, if any, associated with its use. It is the
be evaluated:
responsibility of the user of this standard to establish appro-
3.1.1 Resistance to SCC of a total weldment (weld, heat-
priate safety and health practices and determine the applica-
affected zone, and parent metal) as produced by a specific
bility of regulatory limitations prior to use. (For more specific
welding process;
safety hazards information, see Section 7.)
3.1.2 Resistance to SCC of deposited weld metal;
3.1.3 Determination of a stress level or stress intensity that
will produce SCC in a weldment;
This practice is under the jurisdiction ofASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.06 on Environmen-
tally Assisted Cracking. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2011. Published April 2011. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1985. Last previous edition approved in 2005 as G58–85(2005). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0058-85R11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G58 − 85 (2011)
Procedure:
(a) Specimen size—as required.
(b) Note grain direction and weld longitudinally or across grain.
(c) For multiple-pass welds, grind between passes. Use back gouging from
opposite side to attain 100 % weld penetration.
(d) Discard weld ends.
(e) Remove test sections as required. Sections may be taken across the weld or
longitudinally with the weld.
FIG. 1 Flat Weldment
3.1.4 Evaluation of SCC failure in the specific zones of a It is applicable to materials that can be machined to approxi-
weld (weld metal, partially melted zone, weld interface, mately a 25-mm or 1-in. round.
heat-affected zone, and base metal); and
5.1.4 Direct Tension Weldments (Fig. 4)—These weldments
3.1.5 Evaluationoftheeffectofnotchesandstressraisersin
(3, 4, 5) measure the cracking tendency in weld metal, base
weldments.
metal,orheat-affectedzone.Theappliedstressisdevelopedin
uniaxially loaded tension specimens. Notches may be intro-
4. Significance and Use
duced into the weld metal, base metal, or heat-affected zone.
4.1 Theintentofthispracticeistoindicatestandardwelded
Thetensionspecimensaremachinedfromweldedplateorcast
specimens and welding procedures for evaluating the SCC
sections (Fig. 1) and may be made exclusively from weld
characteristics of weldments in corrosive environments. The
metal.
practice does not recommend the specific corrosive media that
5.1.5 U-Bend Weldment (Fig. 5)—This weldment (5, 6)
may be selected by the user depending upon the intent of his
measures crack tendency in the weld, base metal, and
investigation. Specific corrosive media are included in Prac-
heataffected zone.The bending operation after welding creates
tices G35, G36, G37, and G44. Other environments can be
highlevelsofelasticandplasticstrainresultinginawiderange
used as required.
of stresses in a single specimen. The presence of residual
welding stresses make this a most severe test procedure. It is
5. Types of Specimens and Specific Applications
applicable to any material that can be formed into a U-shape
5.1 This practice covers the following procedures for the without mechanical cracking or localized bending in the
preparation of test weldments. The form of the material to be
heataffected zone.
evaluated (plate, bar, tubing, casting, or forging) may deter- 5.1.6 Bent-Beam Weldment (Fig. 6)—This weldment (4, 5,
mine whether its usage is applicable in a given test. Residual
6) measures cracking tendency in the weld bead, the weldbase
welding stresses may be left intact or they may be fully or
metal interface, and heat-affected zone due to stress concen-
partially removed by an appropriate heat treatment.
tration. The specimen will contain residual welding stresses
5.1.1 Flat Welding (Fig. 1)—This weldment (1) is appli-
and stresses due to elastic strain produced by bending. This
cable for all tension and bend specimens. The size of the
specimen is particularly applicable to materials that cannot be
weldment may be varied according to the needs of the user or
bent into a U-shape.
the demands of welding practice being evaluated. It is appli-
5.1.7 Precracked Cantilever Beam Weldment (Fig. 7)—This
cable to any welding procedure and can involve single- or
weldment (5) measures the level of stress intensity to produce
multiple-pass welds.
crack initiation or propagation in various areas of a weldment.
5.1.2 Circular Bead Weldment (Fig. 2)—This weldment (2,
Notchesorcracksmaybeintroducedintotheweldmetal,base
3, 4, 5) measures the tendency for SCC in the base metal,
metal, or heat-affected zone. The specimen will contain re-
heat-affected zone, and deposited weld metal. The circular
sidual welding stresses and applied stresses. Weldments may
welddevelopsresidualstresses.Itisapplicabletoanymaterial
be prepared in accordance with Fig. 1 or by means of the
form (plate, bar, castings) that can be machined to the
K-preparation for multiple-pass welds (Fig. 8 and Ref (7)).
recommended size. The welding procedure involves one cir-
5.1.8 Tuning Fork Weldment(Fig. 9)—This weldment (5, 9)
cular stringer bead deposit of weld metal.
measures cracking tendency in the base metal, heat-affected
5.1.3 Bead-on-Bar Weldment (Fig. 3)—This weldment (2)
zone, or weld-base metal interface if the weld reinforcement is
measures the tendency for SCC of the base metal. The
not removed. When the reinforcement is removed, cracking
longitudinal fusion welds develop residual stresses on the bar.
may also occur in the weld metal, depending on the suscepti-
bility of the three zones of the weldment and the coincidence
3 of maximum stress with the base metal, heat-affected zone, or
The boldface numbers in parentheses refer to a list of references at the end of
this standard. weldmetal.Stressesareappliedbyclosingthetinesofthefork,
G58 − 85 (2011)
Procedure:
1 1
(a) Specimen size: 100 by 100 by 3 to 12 mm (4 by 4 by ⁄8 to ⁄2 in.)
(b) Clamp or tack weld the edges of the test specimen to a base plate to obtain
restraint.
(c) Weld a 50-mm or 2-in. diameter circular bead using the selected weld process
(Table 1).
(d) Examine both sides of specimen after exposure.
FIG. 2 Circular Bead Weldment
Procedure:
(a) Specimen size: 25-mm (1 in.) diameter by 150 mm (6 in.) long.
(b) Fusion weld (GTAW) entire length on opposite sides.
1 3
(c) Discard 6 mm or ⁄4 in. from ends and remove 20-mm or ⁄4-in. test specimens.
(d) Examine cross section for radial cracking.
FIG. 3 Bead-on-Bar Weldment
Procedure:
(a) Direct tension specimens to be machined directly from flat plate weldment (Fig. 1).
(b) See Practice G49 and Test Methods E8 for recommended dimensions.
FIG. 4 Direct Tension Weldments
and the toe of the weld acts as a metallurgical notch. Tuning- stress is applied by a wedge that is forced into the slit section.
fork specimens may also be machined exclusively from weld
While any material form can be machined into a ring section,
metal. this test is specifically designed for tubing.
5.1.9 Cruciform Weldment (Fig. 10)—This weldment (10)
5.1.11 K-WeldPreparation(Fig.8)—Thisweldment (7)was
will develop the highest degree of weld restraint and residual
specifically designed to test the stress-corrosion cracking
weld stresses. It has been used for evaluating the susceptibility
tendencyinvariouszonesofamultiple-passweld.Notchesare
ofhigh-strengthsteelandarmorplatetounderbeadcrackingin
made in the weld metal, weld interface, heat-affected zone, or
the heat-affected zone of the weld. The welding sequence will
parent metal of cantilever beam-type specimens (Fig. 7). The
produce an increasing degree of restraint with each successive
notches serve as stress concentrators.
weld pass. The number of passes may be varied. Sections are
NOTE 1—Calculated stresses developed in beam specimens, C-rings,
taken from the weldment and if not already cracked may be
and so forth. with weld beads intact will not accurately represent stresses
exposed to SCC environments.
generated in fillets at the edge of the weld beads and in relatively thick
5.1.10 C-Ring and Slit Tubing Weldments (Fig. 11)—These
beads, and strain gages will be needed if precise values of the applied
weldments (2, 4, 5)measurethecrackingtendencyintheweld,
stressarerequired.Theeffectivestressofcoursewillbethealgebraicsum
of the applied stress and residual welding stresses.
base metal, and heat-affected zone. In the C-ring test (Practice
G38), the stress is applied externally. In the slit tubing test, the NOTE 2—Calculated stresses also may be erroneous for bead-off
G58 − 85 (2011)
Procedure:
(a) U-bend specimens to be machined directly from flat plate weldment (Fig. 1)
(b) See Practice G30 for bending method.
NOTE 1—The welds may be oriented 90° to the direction shown.
FIG. 5 U-Bend Weldment
Procedure:
(a) Bent-beam specimens to be machined directly from flat plate weldment. (Fig. 1).
Fulcrum should be notched so as not to contact weld bead.
(b) Dimensions: as required.
(c) See Practice G39 for stress calculations.
NOTE 1—The welds may be oriented 90° to the direction shown.
FIG. 6 Bent-Beam Weldment
Procedure:
(a) Specimens may be machined from flat plate weldment (Fig. 1)orK-weld
preparation (Fig. 8).
(b) See Test Method E399 and Ref (8).
FIG. 7 Precracked Cantilever Beam Weldment
specimens of weldments of dissimilar alloys or in the case of relatively
6.2 Typical welding methods that are applicable to this
soft heat-affected zones.
practice are listed in Table 1.
6.3 Variables introduced by the welding method are (a) the
6. Welding Considerations
amount of heat input introduced by the specific welding
6.1 The choice of a welding method and the application of
process and its effect on microstructure of the weld nugget,
proper welding techniques are major factors influencing the
weld interface, and heat-affected zone of the parent metal, (b)
overall corrosion resistance of a weldment. Each welding
localized variations in chemical composition developed during
method as described in Refs (11, 12) has its own inherent
melting and solidification, (c) the possible pick-up of nitrogen,
characteristics which will govern the overall quality of the
carbon, silicon, fluorine, or other impurities from surface
weld.Theweldingmethodmustthereforebecarefullyselected
contamination,slag,electrodecoatings,fluxes,ordirectlyfrom
and monitored since it will be the governing parameter in the
theatmosphere,(d)lossofelementsacrosstheweldingarc(for
procedure and may introduce a number of variables that will
affect test results. example, chromium), (e) secondary precipitation and other
G58 − 85 (2011)
Procedure:
(a) Double bevel groove butt-weld preparation.
(b) Vertical face buttered with filler metal.
(c) Weld joint completed with multiple passes of filler metal.
(d) Joint machined and notched as required.
(e) See Ref (7).
FIG. 8 K-Weld Preparation
Procedure:
(a) Specimens are machined from parent metal and machined to shape.
(b) Weld bead is applied across the test specimen at the base of one tine.
(c) Either style specimen is appropriate for this test.
FIG. 9 Tuning Fork Weldment
Proce
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