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GB/T 10567.2-2007 (GB/T10567.2-2007)

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GB/T 10567.2-2007: PDF in English (GBT 10567.2-2007)
GB/T 10567.2-2007
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.01
H 25
Replacing GB/T 10567.2-1997, GB/T 8000-2001
Wrought copper and copper alloys - Detection of residual
stress - Ammonia test
ISSUED ON: OCTOBER 25, 2007
IMPLEMENTED ON: APRIL 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Definitions ... 5 
3 Principles ... 5 
4 Instruments ... 6 
5 Reagents ... 6 
6 Specimens ... 6 
7 Test methods and requirements ... 7 
8 Test procedures ... 8 
9 Test report ... 9 
Appendix A (Normative) pH of the test solution ... 10 
Wrought copper and copper alloys - Detection of residual
stress - Ammonia test
1 Scope
This standard specifies the method for detecting residual stress (including applied stress)
in copper and copper alloy processed materials, by ammonia gas accelerated test. These
stresses can cause damage to materials, through stress corrosion cracking, during use
or storage.
This standard applies to the inspection of the residual stress of brass processed materials.
It also applies to the inspection of assemblies and components (limited size).
2 Definitions
2.1
Stress corrosion cracking
Spontaneous damage, which is caused by the rupture of a metal, under the combined
action of corrosion and residual or applied stress.
2.2
Applied stress
Stresses, which are caused and existing inside an object, during the application of
external loads.
2.3
Residual stress
Stress, that remains inside an object, as a result of plastic deformation.
3 Principles
Using the principle of strong stress corrosion cracking sensitivity of brass, in an
ammonia gas atmosphere, the samples are exposed to the ammonia gas atmosphere for
a specified time; then the cracks are examined, under appropriate magnification.
negotiation between the supplier and the buyer.
6.3 Before sampling, it shall avoid handling, bumping, or other actions, which may
bring in other external stresses, that may affect the test results.
6.4 The specimen shall not have defects, such as bending, flattening, scratching, peeling,
wrinkling, bumping and so on. When cutting the specimen, there shall be no applied
stress, such as clamping or artificial breaking. Where it is necessary to mark the
specimen for easy identification, it shall avoid the introduction of applied stress into the
specimen.
7 Test methods and requirements
7.1 The test methods are divided into ammonium chloride test method and ammonia
water test method.
7.1.1 When the heat exchangers adopt brass pipes, it can adopt either the ammonium
chloride test method or the ammonia water test method. The ammonium chloride test
method is used, during arbitration.
7.1.2 The ammonium chloride test method shall be used, for other brass processing
materials.
7.2 Ammonia time
7.2.1 The test time of the ammonium chloride test method is 24 h.
7.2.2 The test time of ammonia water test method is 4 h.
7.3 The test temperature shall be 20 °C ~ 30 °C. The temperature fluctuation, during
the test, shall not exceed ±1 °C. During arbitration, the temperature is maintained at
25 °C ± 1 °C.
7.4 Consumption of test solution
7.4.1 The volume of test solution, which is used in the ammonium chloride test method,
shall be not less than 20% of the total volume of the container, AND not less than 100
mL per square decimeter of specimen's surface area.
7.4.2 The volume of ammonia water, which is used in the ammonia water test method,
is 200 mL.
7.5 The specimen shall be placed in the desiccator, in such a way that the ammonia
vapor can freely reach all surfaces of the specimen; meanwhile there shall be no contact
between the specimens.
7.6 Specimen cleaning and ammonia fumigation shall be carried out in a fume hood.
8 Test procedures
8.1 Prepare ammonium chloride test solution:
Slowly add the sodium hydroxide solution (5.2) into the ammonium chloride solution
(5.1.1), to prepare a test solution, which has a specified pH value of ±0.05 (see
Appendix A). Maintain the solution to room temperature. ADD deionized water, to
dilute it to a volume of 1000 mL. After dilution, use a pH meter (4.1), to check the pH
value.
Note: The preparation of the solution shall be carried out in a fume hood; the solution shall be
stored in a mouth-ground bottle (4.2). The pH of the solution shall be checked again, before
each use; adjust the solution to the specified pH.
8.2 Use a clean organic solvent or hot alkaline solution (5.3), to degrease the specimen.
8.3 After degreasing, wash the specimen in the pickling solution (5.4). When the
concentration of the pickling solution is not enough, add 20 mL ~ 50 mL of hydrogen
peroxide solution (5.5), per liter of the pickling solution. Immediately after pickling,
rinse thoroughly in running water. Finally use an electric blower (4.5), to blow dry the
specimen.
8.4 After the dried specimen has reached the specified test temperature, move it to a
desiccator (4.2), at the same temperature.
8.5 When using the ammonium chloride test method, pour the newly prepared test
solution (8.1), which has the specified pH value (see Appendix A), into the desiccator.
When using the ammonia test method, pour the ammonia water (5.1.2) into the
desiccator. Then immediately cover the desiccator lid. Start timekeeping.
8.6 After reaching the specified test time, take out the specimen from the desiccator.
First rinse it in the water washing tank (4.6). Then put it into the pickling solution (5.4)
for pickling. The pickling time shall be sufficient, that the corrosion products on the
specimen surface are sufficiently removed AND the possible cracks can be observed.
Finally, use water to wash it thoroughly. Use an electric hair dryer (4.5), to blow dry the
specimen.
8.7 Use the magnifying instrument (4.3), to inspect the surface of the specimen for
cracks. If necessary, the specimen can be bent slightly, to make small cracks appear, for
easier observation. For specimens, which have a diameter of less than 0.2 mm, it may
use metallographic microscope (4.4), to check and judge whether the observed cracks
are stress corrosion cracking or intergranular corrosion.
In order to exclude the influence of local stress, which is caused when the specimen is
cut OR the surface of the specimen surface is bumped, the cracks within 5 mm from the
end of the specimen are ignored.
......
 
(Above excerpt was released on 2022-06-04, modified on 2022-06-04, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT10567.2-2007