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ASTM G87-02(2023)

(Practice)

Standard Practice for Conducting Moist SO2 Tests

Standard Practice for Conducting Moist SO<inf>2</inf> Tests

SIGNIFICANCE AND USE
3.1 Moist air containing sulfur dioxide quickly produces easily visible corrosion on many metals in a form resembling that occurring in industrial environments. It is therefore a test medium well suited to detect pores or other sources of weakness in protective coatings and deficiencies in corrosion resistance associated with unsuitable alloy composition or treatments.  
3.2 The results obtained in the test should not be regarded as a general guide to the corrosion resistance of the tested materials in all environments where these materials may be used. Performance of different materials in the test should only be taken as a general guide to the relative corrosion resistance of these materials in moist SO2 service.
SCOPE
1.1 This practice covers the apparatus and procedure to be used in conducting qualitative assessment tests in accordance with the requirements of material or product specifications by means of specimen exposure to condensed moisture containing sulfur dioxide.  
1.2 The exposure conditions may be varied to suit particular requirements and this practice includes provisions for use of different concentrations of sulfur dioxide and for tests either running continuously or in cycles of alternate exposure to the sulfur dioxide containing atmosphere and to the ambient atmosphere.  
1.3 The variant of the test to be used, the exposure period required, the type of test specimen, and the criteria of failure are not prescribed by this practice. Such details are provided in appropriate material and product purchase specifications.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
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.  For a specific warning statement, see 4.3.  
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.

General Information

Status
Published
Publication Date
31-May-2023
ICS
77.060 - Corrosion of metals
Technical Committee
G01 - Corrosion of Metals
Drafting Committee
G01.05 - Laboratory Corrosion Tests
Current Stage
Ref Project

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ASTM G87-02(2023) - Standard Practice for Conducting Moist SO<inf>2</inf> Tests
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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.
Designation: G87 − 02 (Reapproved 2023)
Standard Practice for
1
Conducting Moist SO Tests
2
This standard is issued under the fixed designation G87; 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 2. Referenced Documents
2
1.1 This practice covers the apparatus and procedure to be 2.1 ASTM Standards:
used in conducting qualitative assessment tests in accordance D714 Test Method for Evaluating Degree of Blistering of
with the requirements of material or product specifications by Paints
means of specimen exposure to condensed moisture containing D1193 Specification for Reagent Water
sulfur dioxide. D1654 Test Method for Evaluation of Painted or Coated
Specimens Subjected to Corrosive Environments
1.2 The exposure conditions may be varied to suit particular
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
requirements and this practice includes provisions for use of
sion Test Specimens
different concentrations of sulfur dioxide and for tests either
G46 Guide for Examination and Evaluation of Pitting Cor-
running continuously or in cycles of alternate exposure to the
rosion
sulfur dioxide containing atmosphere and to the ambient
atmosphere.
3. Significance and Use
1.3 The variant of the test to be used, the exposure period
3.1 Moist air containing sulfur dioxide quickly produces
required, the type of test specimen, and the criteria of failure
easily visible corrosion on many metals in a form resembling
are not prescribed by this practice. Such details are provided in
that occurring in industrial environments. It is therefore a test
appropriate material and product purchase specifications.
medium well suited to detect pores or other sources of
1.4 The values stated in SI units are to be regarded as weakness in protective coatings and deficiencies in corrosion
standard. The values given in parentheses are for information resistance associated with unsuitable alloy composition or
only. treatments.
1.5 This standard does not purport to address all of the
3.2 The results obtained in the test should not be regarded as
safety concerns, if any, associated with its use. It is the
a general guide to the corrosion resistance of the tested
responsibility of the user of this standard to establish appro-
materials in all environments where these materials may be
priate safety, health, and environmental practices and deter-
used. Performance of different materials in the test should only
mine the applicability of regulatory limitations prior to use.
be taken as a general guide to the relative corrosion resistance
For a specific warning statement, see 4.3.
of these materials in moist SO service.
2
1.6 This international standard was developed in accor-
4. Apparatus
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.1 The apparatus required for moist SO testing consists of
2
3
Development of International Standards, Guides and Recom-
a test chamber having an internal capacity of 300 L (10.6 ft ),
mendations issued by the World Trade Organization Technical
a supply of sulfur dioxide with metering device, specimen
Barriers to Trade (TBT) Committee.
supports, provisions for heating the chamber, and necessary
means of control. The size and detailed construction of the
apparatus are optional, provided the conditions obtained meet
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.05 on Laboratory
2
Corrosion Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2023. Published June 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2018 as G87 – 02 (2018). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0087-02R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G87 − 02 (2023)
the requirements of this practice. Suitable apparatus which may 7.2 The total combined exposed surface area of the material
be used to obtain these conditions is described in Appendix X1. tested at any one time should be substantially the same and
2 2
unless otherwise agreed upon, it shall b
...

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ASTM G35-23(Practice)
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4.1 Polythionic acids are chemically described as H2SxO6, where x is usually 3, 4, or 5 (1)3 though can be more than 50 (2). These acid environments provide a way of evaluating the resistance of stainless steels and related alloys to intergranular stress corrosion cracking. Failure is accelerated by the presence of increasing amounts of intergranular precipitate. Results for the polythionic acid test have not been correlated exactly with those of intergranular corrosion tests (Test Methods G28). Also, this test may not be relevant to stress corrosion cracking in chlorides or caustic environments.  
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3.1 Electrochemical corrosion rate measurements often provide results in terms of electrical current. Although the conversion of these current values into mass loss rates or penetration rates is based on Faraday’s Law, the calculations can be complicated for alloys and metals with elements having multiple valence values. This practice is intended to provide guidance in calculating mass loss and penetration rates for such alloys. Some typical values of equivalent weights for a variety of metals and alloys are provided.  
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ASTM G123-00(2022)e1(Test Method)
Standard Test Method for Evaluating Stress-Corrosion Cracking of Stainless Alloys with Different Nickel Content in Boiling Acidified Sodium Chloride Solution

SIGNIFICANCE AND USE
5.1 This test method is designed to compare alloys and may be used as one method of screening materials prior to service. In general, this test method is more useful for stainless steels than the boiling magnesium chloride test of Practice G36. The boiling magnesium chloride test cracks materials with the nickel levels found in relatively resistant austenitic and duplex stainless steels, thus making comparisons and evaluations for many service environments difficult.  
5.2 This test method is intended to simulate cracking in water, especially cooling waters that contain chloride. It is not intended to simulate cracking that occurs at high temperatures (greater than 200 °C or 390 °F) with chloride or hydroxide.
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5.5 The repeatability and reproducibility data from Section 12 and Appendix X1 must be considered prior to use. Interlaboratory variation in results may be expected as occurs with many corrosion tests. Acceptance criteria are not part of this test method and if needed are to be negotiated by the user and the producer.
SCOPE
1.1 This test method covers a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25 % (by mass) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested.  
1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing (see Section 12) using this sodium chloride test method.  
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ASTM G30-22(Practice)
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.  
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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 that 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.  
FIG. 1 Typical Stressed U-bends  
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5.1 Autoclave tests are commonly used to evaluate the corrosion performance of metallic and non-metallic materials under simulated HP and HTHP service conditions. Examples of service environments in which HP and HTHP corrosion tests have been used include chemical processing, petroleum production and refining, food processing, pressurized cooling water, electric power systems, and aerospace propulsion.  
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SCOPE
1.1 This guide covers procedures, specimens, and equipment for conducting laboratory corrosion tests on metallic materials under conditions of high pressure (HP) or the combination of high temperature and high pressure (HTHP). See 3.2 for definitions of high pressure and temperature.  
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.  
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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.  
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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.  
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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.  
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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  
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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.  
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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.  
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ASTM G39-99(2021)(Practice)
Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens

SIGNIFICANCE AND USE
5.1 The bent-beam specimen is designed for determining the stress-corrosion behavior of alloy sheets and plates in a variety of environments. The bent-beam specimens are designed for testing at stress levels below the elastic limit of the alloy. For testing in the plastic range, U-bend specimens should be employed (see Practice G30). Although it is possible to stress bent-beam specimens into the plastic range, the stress level cannot be calculated for plastically-stressed three- and four-point loaded specimens as well as the double-beam specimens. Therefore, the use of bent-beam specimens in the plastic range is not recommended for general use.
SCOPE
1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens.  
1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice is applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1). Stress calculations by this practice are not applicable to plastically stressed specimens.  
Note 1: It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction (1).2  
1.3 Test procedures are given for stress-corrosion testing by exposure to gaseous and liquid environments.  
1.4 The bent-beam test is best suited for flat product forms, such as sheet, strip, and plate. For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens. A double-beam modification of a four-point loaded specimen to utilize heavier materials is described in 10.5.  
1.5 The exposure of specimens in a corrosive environment is treated only briefly since other practices deal with this aspect, for example, Practices D1141, G30, G36, G44, G50, and G85. The experimenter is referred to ASTM Special Technical Publication 425 (2).  
1.6 The bent-beam practice generally constitutes a constant strain (deflection) test. Once cracking has initiated, the state of stress at the tip of the crack as well as in uncracked areas has changed, and therefore, the known or calculated stress or strain values discussed in this practice apply only to the state of stress existing before initiation of cracks.  
1.7 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.  
1.8  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. (For more specific safety hazard information see Section 7 and 12.1.)  
1.9 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 G82-98(2021)e1(Guide)
Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance

SIGNIFICANCE AND USE
4.1 When two dissimilar metals in electrical contact are exposed to a common electrolyte, one of the metals can undergo increased corrosion while the other can show decreased corrosion. This type of accelerated corrosion is referred to as galvanic corrosion. Because galvanic corrosion can occur at a high rate, it is important that a means be available to alert the user of products or equipment that involve the use of dissimilar metal combinations in an electrolyte of the possible effects of galvanic corrosion.  
4.2 One method that is used to predict the effects of galvanic corrosion is to develop a galvanic series by arranging a list of the materials of interest in order of observed corrosion potentials in the environment and conditions of interest. The metal that will suffer increased corrosion in a galvanic couple in that environment can then be predicted from the relative position of the two metals in the series.  
4.3 Types of Galvanic Series:  
4.3.1 One type of Galvanic Series lists the metals of interest in order of their corrosion potentials, starting with the most active (electronegative) and proceeding in order to the most noble (electropositive). The potentials themselves (versus an appropriate reference half-cell) are listed so that the potential difference between metals in the series can be determined. This type of Galvanic Series has been put in graphical form as a series of bars displaying the range of potentials exhibited by the metal listed opposite each bar. Such a series is illustrated in Fig. 1.    
4.4 Use of a Galvanic Series:  
4.4.1 Generally, upon coupling two metals in the Galvanic Series, the more active (electronegative) metal will have a tendency to undergo increased corrosion while the more noble (electropositive) metal will have a tendency to undergo reduced corrosion.  
4.4.2 Usually, the further apart two metals are in the series, and thus the greater the potential difference between them, the greater is the driving force f...
SCOPE
1.1 This guide covers the development of a galvanic series and its subsequent use as a method of predicting the effect that one metal can have upon another metal can when they are in electrical contact while immersed in an electrolyte. Suggestions for avoiding known pitfalls are included.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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. Specific precautionary statements are given in Section 5.  
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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