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ASTM G30-97(2016)

(Practice)

Standard Practice for Making and Using U-Bend Stress-Corrosion Test Specimens

Standard Practice for Making and Using U-Bend Stress-Corrosion Test Specimens

SIGNIFICANCE AND USE
5.1 The U-bend specimen may be used for any metal alloy sufficiently ductile to be formed into the U-shape without mechanically cracking. The specimen is most easily made from strip or sheet but can be machined from plate, bar, castings, or weldments; wire specimens may be used also.  
5.2 Since the U-bend usually contains large amounts of elastic and plastic strain, it provides one of the most severe tests available for smooth (as opposed to notched or precracked) stress-corrosion test specimens. The stress conditions are not usually known and a wide range of stresses exist in a single stressed specimen. The specimen is therefore unsuitable for studying the effects of different applied stresses on stress-corrosion cracking or for studying variables which have only a minor effect on cracking. The advantage of the U-bend specimen is that it is simple and economical to make and use. It is most useful for detecting large differences between the stress-corrosion cracking resistance of (a) different metals in the same environment, (b) one metal in different metallurgical conditions in the same environment, or (c) one metal in several environments.
SCOPE
1.1 This practice covers procedures for making and using U-bend specimens for the evaluation of stress-corrosion cracking in metals. The U-bend specimen is generally a rectangular strip which is bent 180° around a predetermined radius and maintained in this constant strain condition during the stress-corrosion test. Bends slightly less than or greater than 180° are sometimes used. Typical U-bend configurations showing several different methods of maintaining the applied stress are shown in Fig. 1.    
1.2 U-bend specimens usually contain both elastic and plastic strain. In some cases (for example, very thin sheet or small diameter wire) it is possible to form a U-bend and produce only elastic strain. However, bent-beam (Practice G39 or direct tension (Practice G49)) specimens are normally used to study stress-corrosion cracking of strip or sheet under elastic strain only.  
1.3 This practice is concerned only with the test specimen and not the environmental aspects of stress-corrosion testing which are discussed elsewhere (1)2 and in Practices G35, G36, G37, G41, G44, G103 and Test Method G123.  
1.4 The values stated in SI units are to be regarded as standard. The inch-pound units in parentheses are provided for information.  
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.

General Information

Status
Historical
Publication Date
30-Apr-2016
ICS
77.060 - Corrosion of metals
Technical Committee
G01 - Corrosion of Metals
Drafting Committee
G01.06 - Environmentally Assisted Cracking
Current Stage
Ref Project

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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: G30 − 97 (Reapproved 2016)
Standard Practice for
Making and Using U-Bend Stress-Corrosion Test
1
Specimens
ThisstandardisissuedunderthefixeddesignationG30;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
3
1.1 This practice covers procedures for making and using
2.1 ASTM Standards:
U-bendspecimensfortheevaluationofstress-corrosioncrack-
E3Guide for Preparation of Metallographic Specimens
ing in metals. The U-bend specimen is generally a rectangular
G1Practice for Preparing, Cleaning, and Evaluating Corro-
strip which is bent 180° around a predetermined radius and
sion Test Specimens
maintained in this constant strain condition during the stress-
G15TerminologyRelatingtoCorrosionandCorrosionTest-
4
corrosiontest.Bendsslightlylessthanorgreaterthan180°are
ing (Withdrawn 2010)
sometimes used. Typical U-bend configurations showing sev-
G35Practice for Determining the Susceptibility of Stainless
eral different methods of maintaining the applied stress are
Steels and Related Nickel-Chromium-Iron Alloys to
shown in Fig. 1.
Stress-Corrosion Cracking in Polythionic Acids
1.2 U-bend specimens usually contain both elastic and
G36Practice for Evaluating Stress-Corrosion-Cracking Re-
plastic strain. In some cases (for example, very thin sheet or
sistance of Metals and Alloys in a Boiling Magnesium
small diameter wire) it is possible to form a U-bend and
Chloride Solution
produceonlyelasticstrain.However,bent-beam(PracticeG39
G37Practice for Use of Mattsson’s Solution of pH 7.2 to
or direct tension (Practice G49)) specimens are normally used
Evaluate the Stress-Corrosion Cracking Susceptibility of
tostudystress-corrosioncrackingofstriporsheetunderelastic
Copper-Zinc Alloys
strain only.
G39Practice for Preparation and Use of Bent-Beam Stress-
Corrosion Test Specimens
1.3 This practice is concerned only with the test specimen
and not the environmental aspects of stress-corrosion testing G41Practice for Determining Cracking Susceptibility of
2
which are discussed elsewhere (1) and in Practices G35, G36, Metals Exposed Under Stress to a Hot Salt Environment
G37, G41, G44, G103 and Test Method G123. G44PracticeforExposureofMetalsandAlloysbyAlternate
Immersion in Neutral 3.5 % Sodium Chloride Solution
1.4 The values stated in SI units are to be regarded as
G49Practice for Preparation and Use of Direct Tension
standard.The inch-pound units in parentheses are provided for
Stress-Corrosion Test Specimens
information.
G103PracticeforEvaluatingStress-CorrosionCrackingRe-
1.5 This standard does not purport to address all of the
sistance of Low Copper 7XXX Series Al-Zn-Mg-Cu
safety concerns, if any, associated with its use. It is the
Alloys in Boiling 6% Sodium Chloride Solution
responsibility of the user of this standard to establish appro-
G123TestMethodforEvaluatingStress-CorrosionCracking
priate safety and health practices and determine the applica-
of Stainless Alloys with Different Nickel Content in
bility of regulatory limitations prior to use.
Boiling Acidified Sodium Chloride Solution
1
This practice is under the jurisdiction ofASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.06 on Environmen-
3
tally Assisted Cracking. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2016. Published June 2016. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin1972.Lastpreviouseditionapprovedin2015asG30–97(2015).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0030-97R16. the ASTM website.
2 4
The boldface numbers in parentheses refer to a list of references at the end of The last approved version of this historical standard is referenced on
this standard. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G30 − 97 (2016)
FIG. 1 Typical Stressed U-bends
3. Terminology It is most useful for detecting large differences between the
stress-corrosion cracking resistance of (a) different metals in
3.1 For definitions of corrosion-related terms used in this
the same environment, (b) one metal in different metallurgical
practice see Terminology G15.
conditionsinthesameenvironment,or(c)onemetalinseveral
environments.
4. Summary of Practice
4.1 This practice involves the stressing of a specimen bent
6. Hazards
to a U shape. The applied strain is estimated from the bend
6.1 U-bends made from high strength materi
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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: G30 − 97 (Reapproved 2015) G30 − 97 (Reapproved 2016)
Standard Practice for
Making and Using U-Bend Stress-Corrosion Test
1
Specimens
This standard is issued under the fixed designation G30; 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 practice covers procedures for making and using U-bend specimens for the evaluation of stress-corrosion cracking in
metals. The U-bend specimen is generally a rectangular strip which is bent 180° around a predetermined radius and maintained
in this constant strain condition during the stress-corrosion test. Bends slightly less than or greater than 180° are sometimes used.
Typical U-bend configurations showing several different methods of maintaining the applied stress are shown in Fig. 1.
1.2 U-bend specimens usually contain both elastic and plastic strain. In some cases (for example, very thin sheet or small
diameter wire) it is possible to form a U-bend and produce only elastic strain. However, bent-beam (Practice G39 or direct tension
(Practice G49)) specimens are normally used to study stress-corrosion cracking of strip or sheet under elastic strain only.
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.06 on Environmentally
Assisted Cracking.
Current edition approved Nov. 1, 2015May 1, 2016. Published November 2015June 2016. Originally approved in 1972. Last previous edition approved in 20092015 as
G30–97(2009).G30 – 97 (2015). DOI: 10.1520/G0030-97R15.10.1520/G0030-97R16.
FIG. 1 Typical Stressed U-bends
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G30 − 97 (2016)
1.3 This practice is concerned only with the test specimen and not the environmental aspects of stress-corrosion testing which
2
are discussed elsewhere (1) and in Practices G35, G36, G37, G41, G44, G103 and Test Method G123.
1.4 The values stated in SI units are to be regarded as standard. The inch-pound units in parentheses are provided for
information.
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.
2. Referenced Documents
3
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
4
G15 Terminology Relating to Corrosion and Corrosion Testing (Withdrawn 2010)
G35 Practice for Determining the Susceptibility of Stainless Steels and Related Nickel-Chromium-Iron Alloys to Stress-
Corrosion Cracking in Polythionic Acids
G36 Practice for Evaluating Stress-Corrosion-Cracking Resistance of Metals and Alloys in a Boiling Magnesium Chloride
Solution
G37 Practice for Use of Mattsson’s Solution of pH 7.2 to Evaluate the Stress-Corrosion Cracking Susceptibility of Copper-Zinc
Alloys
G39 Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
G41 Practice for Determining Cracking Susceptibility of Metals Exposed Under Stress to a Hot Salt Environment
G44 Practice for Exposure of Metals and Alloys by Alternate Immersion in Neutral 3.5 % Sodium Chloride Solution
G49 Practice for Preparation and Use of Direct Tension Stress-Corrosion Test Specimens
G103 Practice for Evaluating Stress-Corrosion Cracking Resistance of Low Copper 7XXX Series Al-Zn-Mg-Cu Alloys in
Boiling 6 % Sodium Chloride Solution
G123 Test Method for Evaluating Stress-Corrosion Cracking of Stainless Alloys with Different Nickel Content in Boiling
Acidified Sodium Chloride Solution
3. Terminology
3.1 For definitions of corrosion-related terms used in this practice see Terminology G15.
4. Summary of Practice
4.1 This practice involves the stressing of a specimen bent to a U shape. The applied strain is estimated from the bend
conditions. The stressed specimens are then exposed to the test environment and the time required for cracks to develop is
determined. This cracking time is used as an estimate of the stress corrosion resistance of the material in the test environment.
5. Signific
...

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ASTM G49-85(2023)e1(Practice)
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SIGNIFICANCE AND USE
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SIGNIFICANCE AND USE
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5.1 The U-bend specimen may be used for any metal alloy sufficiently ductile to be formed into the U-shape without mechanically cracking. The specimen is most easily made from strip or sheet but can be machined from plate, bar, castings, or weldments; wire specimens may be used also.  
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FIG. 1 Typical Stressed U-bends  
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1.2 The procedures and methods in this guide are applicable for conducting mass loss corrosion, localized corrosion, and electrochemical tests as well as for use in environmentally induced cracking tests that need to be conducted under HP or HTHP conditions.  
1.3 The primary purpose for this guide is to promote consistency of corrosion test results. Furthermore, this guide will aid in the comparison of corrosion data between laboratories or testing organizations that utilize different equipment.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM G46-21(Guide)
Standard Guide for Examination and Evaluation of Pitting Corrosion

SIGNIFICANCE AND USE
4.1 It is important to be able to determine the extent of pitting, either in a service application in which it is necessary to predict the remaining life in a metal structure, or in laboratory test programs that are used to select the most pitting-resistant materials for service. The purpose of the study is crucial in determining the appropriate examination and evaluation steps.  
4.2 Some typical purposes of laboratory tests include, but are not limited to, evaluating performance of alloys, determining whether an alloy is resistant to the environment, evaluating how environmental conditions including corrosion inhibitor affect or prevent pitting, and evaluating whether a lot of metal is sufficiently resistant for its use in a particular application or environment.  
4.3 Some typical purposes of field studies include, but are not limited to, determining if pits are likely to grow and cause leak or release of process fluid, and assisting a determination of whether to replace or repair damage from pits (remaining life assessment).
SCOPE
1.1 This guide covers the selection of procedures that can be used in the examination and evaluation of pitted metals. These procedures include both nondestructive and destructive approaches.  
1.2 The procedures covered in this guide include those that may be used in laboratory evaluations of corroded metal specimens and field examinations and inspections.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3.1 Exception—In X1.2.1, mils per year (MPY) are regarded as standard for the target corrosion rate.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM G37-98(2021)(Practice)
Standard Practice for Use of Mattsson's Solution of pH 7.2 to Evaluate the Stress-Corrosion Cracking Susceptibility of Copper-Zinc Alloys

SIGNIFICANCE AND USE
4.1 This test environment is believed to give an accelerated ranking of the relative or absolute degree of stress-corrosion cracking susceptibility for different brasses. It has been found to correlate well with the corresponding service ranking in environments that cause stress-corrosion cracking which is thought to be due to the combined presence of traces of moisture and ammonia vapor. The extent to which the accelerated ranking correlates with the ranking obtained after long-term exposure to environments containing corrodents other than ammonia is not at present known. Examples of such environments may be severe marine atmospheres (Cl−), severe industrial atmospheres (predominantly SO2), and super-heated ammonia-free steam.  
4.2 It is not possible at present to specify any particular time to failure (defined on the basis of any particular failure criteria) in pH 7.2 Mattsson’s solution that corresponds to a distinction between acceptable and unacceptable stress-corrosion behavior in brass alloys. Such particular correlations must be determined individually.  
4.3 Mattsson's solution of pH 7.2 may also cause stress independent general and intergranular corrosion of brasses to some extent. This leads to the possibility of confusing stress-corrosion failures with mechanical failures induced by corrosion-reduced net cross sections. This danger is particularly great with small cross section specimens, high applied stress levels, long exposure periods and stress-corrosion resistant alloys. Careful metallographic examination is recommended for correct diagnosis of the cause of failure. Alternatively, unstressed control specimens may be exposed to evaluate the extent to which stress independent corrosion degrades mechanical properties.
SCOPE
1.1 This practice covers the preparation and use of Mattsson’s solution of pH 7.2 as an accelerated stress-corrosion cracking test environment for brasses (copper-zinc base alloys). The variables (to the extent that these are known at present) that require control are described together with possible means for controlling and standardizing these variables.  
1.2 This practice is recommended only for brasses (copper-zinc base alloys). The use of this test environment is not recommended for other copper alloys since the results may be erroneous, providing completely misleading rankings. This is particularly true of alloys containing aluminum or nickel as deliberate alloying additions.  
1.3 This practice is intended primarily where the test objective is to determine the relative stress-corrosion cracking susceptibility of different brasses under the same or different stress conditions or to determine the absolute degree of stress corrosion cracking susceptibility, if any, of a particular brass or brass component under one or more specific stress conditions. Other legitimate test objectives for which this test solution may be used do, of course, exist. The tensile stresses present may be known or unknown, applied or residual. The practice may be applied to wrought brass products or components, brass castings, brass weldments, and so forth, and to all brasses. Strict environmental test conditions are stipulated for maximum assurance that apparent variations in stress-corrosion susceptibility are attributable to real variations in the material being tested or in the tensile stress level and not to environmental variations.  
1.4 This practice relates solely to the preparation and control of the test environment. No attempt is made to recommend surface preparation or finish, or both, as this may vary with the test objectives. Similarly, no attempt is made to recommend particular stress-corrosion test specimen configurations or methods of applying the stress. Test specimen configurations that may be used are referenced in Practice G30 and STP 425.2  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included ...

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ASTM
ASTM G186-05(2021)(Test Method)
Standard Test Method for Determining Whether Gas-Leak-Detector Fluid Solutions Can Cause Stress Corrosion Cracking of Brass Alloys

SIGNIFICANCE AND USE
5.1 Brass components are routinely used in compressed gas service for valves, pressure regulators, connectors and many other components. Although soft brass is not susceptible to ammonia SCC, work-hardened brass is susceptible if its hardness exceeds about 54 HR 30T (55HRB) (Rockwell scale). Normal assembly of brass components should not induce sufficient work hardening to cause susceptibility to ammonia SCC. However, it is has been observed that over-tightening of the components will render them susceptible to SCC, and the problem becomes more severe in older components that have been tightened many times. In this test, the specimens are obtained in the hardened condition and are strained beyond the elastic limit to accelerate the tendency towards SCC.  
5.2 It is normal practice to use LDFs to check pressurized systems to assure that leaking is not occurring. LDFs are usually aqueous solutions containing surfactants that will form bubbles at the site of a leak. If the LDF contains ammonia or other agent that can cause SCC in brass, serious damage can occur to the system that will compromise its safety and integrity.  
5.3 It is important to test LDFs to assure that they do not cause SCC of brass and to assure that the use of these products does not compromise the integrity of the pressure containing system.  
5.4 It has been found that corrosion of brass is necessary before SCC can occur. The reason for this is that the corrosion process results in cupric and cuprous ions accumulating in the electrolyte. Therefore, adding copper metal and cuprous oxide (Cu2O) to the aqueous solution accelerates the SCC process if agents that cause SCC are present. However, adding these components to a solution that does not cause SCC will not make stressed brass crack.  
5.5 Repeated application of the solution to the specimen followed by a drying period causes the components in the solution to concentrate thereby further increasing the rate of cracking. This also simulates se...
SCOPE
1.1 This test method covers an accelerated test method for evaluating the tendency of gas leak detection fluids (LDFs) to cause stress corrosion cracking (SCC) of brass components in compressed gas service.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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