ASTM G37 - 98 (2025) 用pH值为7.2的玛特松(mattsson's)溶液评价铜锌合金的应力腐蚀断裂灵敏性

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Designation: G37 −98 (Reapproved 2025)
Standard Practice for
Use of Mattsson’s Solution of pH 7.2 to Evaluate the Stress-
Corrosion Cracking Susceptibility of Copper-Zinc Alloys
1
This standard is issued under the ﬁxed designation G37; 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 the preparation and use of Matts-
son’s solution of pH 7.2 as an accelerated stress-corrosion
cracking test environment for brasses (copper-zinc base al-
loys). The variables (to the extent that these are known at
present) that require control are described together with pos-
sible 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 objec-
tive 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 maxi-
mum 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 environ-
mental 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 conﬁgu-
rations 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 in this
standard.
1.6 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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
(For more speciﬁc safety hazard statements see Section 8.)
1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
3
D1193 Speciﬁcation for Reagent Water
G30 Practice for Making and Using U-Bend Stress-
Corrosion Test Specimens
3. Summary of Practice
3.1 This practice consists of completely and continuously
immersing a stressed test specimen in an aqueous solution
containing 0.05 g-atom/L of Cu
++
and 1 g-mol/L of NH
4
+
and
of pH 7.2. The copper is added as CuSO
4
·5H
2
O and the NH
4
+
as a mixture of NH
4
OH and (NH
4
)
2
SO
4
. The ratio of these
latter two compounds is adjusted to give the desired pH.
Exposure time, criterion of failure, and so forth, are variable
and not speciﬁcally recommended.
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 Environmen-
tally Assisted Cracking.
Current edition approved Oct. 1, 2025. Published October 2025. Originally
approved in 1973. Last previous edition approved in 2021 as G37 – 98 (2021). DOI:
10.1520/G0037-98R25.
2
STP425, Stress Corrosion Testing, ASTM International.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at www.astm.org/contact. 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
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.
1

4. 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 accel-

erated 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 SO

), 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 particu-

larly great with small cross section specimens, high applied

stress levels, long exposure periods and stress-corrosion resis-

tant alloys. Careful metallographic examination is recom-

mended 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.

5. Apparatus

5.1 Any suitable inert container may be used to hold the test

solution and test specimens during exposure. Glass or plastic is

highly recommended. The container should be ﬁtted with a

removable top to reduce evaporation during test, thus prevent-

ing dust and other particulate matter from entering the

environment, and facilitating periodic inspection of the speci-

mens. The top should not, however, be airtight, but instead

should permit reasonably free access of laboratory air to the

surface of the environment. The container and top should not

be transparent and should be fully opaque to light.

5.2 Specimen Holders should be designed to insulate elec-

trically the test specimens from each other and from any other

bare metal. They should also be completely inert to the test

environment so that leaching of soluble components or direct

reaction with the test environment will not interfere with the

test. The shape and form of the specimen holders and supports

should be such that they do not interfere with free access to the

test environment to the test specimen and its stressed surfaces.

6. Reagents and Materials

6.1 Reagent grade copper sulfate crystals (CuSO

·5H

O),

ammonium sulfate crystals ((NH

)

), and concentrated

ammonium hydroxide solution (NH

OH) (28 % to 30 % NH

assayed and 0.90 sp gr) conforming to the speciﬁcations of the

Committee on Analytical Reagents of the American Chemical

Society shall be used.

6.2 Purity of Water—Reagent water Type IV (Speciﬁcation

D1193) shall be used to prepare the test solution.

7. Test Solution

7.1 The concentration of the test solution shall be 0.05

g-atom/L with respect to Cu

and 1.0 g-mol/L with respect to

. The pH of the test solution shall be 7.2 + 0.3, −0.1 pH.

7.2 The test solution shall be prepared by completely

dissolving 590.0 g 61.0 g of (NH

)

in 4 L of water and

by completely dissolving 125.0 g 60.5 g of CuSO

·5H

O in

1 L of water. These two solutions should then be thoroughly

mixed and 71.0 mL 60.2 mL of NH

OH solution added,

preferably with a buret. Finally, the whole should be diluted to

10.0 L 60.1 L and allowed to age for 48 h to 96 h in the test

container prior to use. It is not recommended that the solution

be stored for extended periods or used without the speciﬁed

aging. Smaller or larger volumes of solution can be prepared

using lesser amounts of reagents in the same proportions.

7.3 After aging, the pH of the test solution should be

measured. If outside the range speciﬁed above, the pH may be

adjusted to within the range 7.1 to 7.5 by the addition of fresh

pH 4 or pH 10 Mattsson’s solution. Addition of NH

OH or

to adjust pH is not recommended since the concentra-

tion of the various soluble ions can be considerably altered.

7.4 Temperature control of the test solution is not recom-

mended. Instead, the room air temperature should be controlled

at 21 °C 63 °C and the test solution allowed to reach its

equilibrium temperature with the air. No room air relative

humidity control is recommended and temperature recording is

not mandatory.

7.5 The volume of test solution used should be sufficiently

large to avoid any appreciable change in corrosivity due to

either exhaustion of corrosive constituents or accumulation of

corrosion products. An arbitrary minimum ratio between the

volume of test solution and the exposed specimen surface area

of 3 L/dm

(30 mL/cm

) is recommended.

7.6 The test solution should be changed after every 7 days

of specimen exposure time by transferring the test specimens to

a new batch of 48 h aged test solution. Evaporation losses

should be replenished with reagent water Type IV (Speciﬁca-

tion D1193) as frequently as deemed necessary. As far as

possible, the air above the solution should be static to minimize

water and ammonia evaporation. Forced ventilation should be

avoided. It has not been found necessary to check or adjust the

pH of the test solution during test after the initial 48 h aging

period.

ACS Reagent Chemicals, Speciﬁcations and Procedures for Reagents and

Standard-Grade Reference Materials, American Chemical Society, Washington,

DC. For suggestions on the testing of reagents not listed by the American Chemical

Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,

U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-

copeial Convention, Inc. (USPC), Rockville, MD.

G37 − 98 (2025)

8. Hazards

8.1 The test solution presents no undue safety hazard. It is

recommended, however, that rubber gloves and shatterproof

goggles be worn during inspection.

8.2 The solution contains copper and is poisonous and

should not be ingested.

8.3 Should any of the solution come into contact with the

eyes, qualiﬁed medical aid should be obtained immediately.

8.4 (NH

)

has been reported to be allergenic. Repeated

short-time skin contact with the solution over extended periods

of time should be avoided.

8.5 The fumes given off by the test solution contain ammo-

nia. The least detectable ammonia odor corresponds to a

concentration of 50 ppm; 100 ppm can be tolerated for several

hours without serious disturbance; 700 ppm causes immediate

eye irritation; and greater than 5000 ppm can be lethal. The test

should therefore be run in a well ventilated area.

9. Calibration and Standardization

9.1 When a new test facility is established, calibration tests

should be conducted to determine how the results obtained

compare with published data.

9.2 A suitable supply of control material which can be

exposed periodically to conﬁrm the reproducibility of the test

procedure should be available.

10. Procedure

10.1 Completely and continuously immerse the test speci-

mens in the test solution with the exception of periodic

withdrawals for inspection or measurement. Gently rinse the

specimens in distilled water after each withdrawal and when

the test solution is being changed.

10.2 The duration of the test will be determined solely by

the material being tested. Highly susceptible alloys or highly

stressed alloys may fail with extreme rapidity. Moderately

stressed alloys may take considerable time to fail. Generally,

failures are not observed after periods of greater than 1000 h.

It is therefore recommended that this be the longest duration of

the test.

11. Cleaning

11.1 After completion of the test, rinse the specimens well

in distilled water and air dry.

11.2 Any other cleaning may be performed, depending on

test objective and method of failure determination.

12. Report

12.1 The report shall include the following:

12.1.1 Chemical composition, thermal treatments, mechani-

cal treatments, and mechanical properties of the material,

12.1.2 Microstructure and grain size of the material,

12.1.3 Size, type, and orientation of the test specimens,

12.1.4 Surface treatment and preparation procedures of the

test specimens,

12.1.5 In conﬁgurations where the stress level is known, the

applied tensile stress,

12.1.6 Ratio of test solution volume to exposed specimen

surface area,

12.1.7 Total duration of the test and the frequency of

inspection periods,

12.1.8 Measured pH of the test solution and the NH

content if determined analytically,

12.1.9 Criterion used for deﬁnition of failure,

12.1.10 Number of specimens tested,

12.1.11 Details of the solution container, specimen loading

jigs, and so forth, where these are in any way exceptional,

12.1.12 Method used to clean the test specimens after

exposure, and

12.1.13 Any intentional or inadvertent deviations from the

recommended test procedures and any other information that

the investigator considers pertinent.

13. Keywords

13.1 accelerated stress-corrosion cracking test environment;

continuous immersion; copper-ammonium sulfate solution;

copper-zinc alloys

ANNEX

(Mandatory Information)

A1. PREPARATION OF MATTSSON’S SOLUTION OF pH 4 AND pH 10

A1.1 The preparation of Mattsson’s solution of pH 4 and

pH 10 is provided in this annex to enable the pH of Mattsson’s

solution, pH 7.2, to be adjusted correctly.

A1.2 Mattsson’s Solution of pH 4:

(1) 66 g (NH

)

(2) 12.5 g CuSO

·5H

O plus reagent water Type IV (Speci-

ﬁcation D1193) to make 1 L.

A1.2.1 Proceed as for Mattsson’s solution of pH 7.2. The

pH is insensitive to composition and adjustment should not be

required. The solution should be 1 Mwith respect to NH

and

0.05 Mwith respect to Cu

A1.3 Mattsson’s Solution of pH 10:

(1) 15.2 g (NH

)

(2) 12.5 g CuSO

·5H

G37 − 98 (2025)

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摘要：

本文档详细介绍ASTM G37 - 98 (2025)标准，即采用pH值为7.2的玛特松（Mattsson's）溶液评价铜锌合金应力腐蚀断裂敏感性的标准试验方法。该标准规定了通过特定腐蚀溶液和应力加载条件，快速评估铜锌合金（包括黄铜等）在含氨环境中抗应力腐蚀开裂性能的标准化程序。pH值精确控制在7.2的玛特松溶液能够模拟典型服役环境，帮助工程师和科研人员判断材料在拉应力与腐蚀介质协同作用下的开裂倾向。标准涵盖试样制备、溶液配制、试验装置、加载方式、试验持续时间和结果评定等完整流程，适用于质量控制

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ASTM G37 - 98 (2025) 用pH值为7.2的玛特松(mattsson's)溶液评价铜锌合金的应力腐蚀断裂灵敏性

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