ASTM B858-95
(Test Method)Standard Test Method for Ammonia Vapor Test for Determination Susceptibility to Stress Corrosion Cracking in Copper Alloys
Standard Test Method for Ammonia Vapor Test for Determination Susceptibility to Stress Corrosion Cracking in Copper Alloys
SCOPE
1.1 This test method describes a procedure to determine the presence of residual stresses in wrought copper alloy products that may lead to stress corrosion cracking. An ammonia vapor atmosphere is used as an accelerated test.
1.2 This test method is only suitable for products fabricated from copper alloys that are known to be susceptible to stress corrosion cracking in ammonia vapor atmospheres. It is intended to create an environmental condition of reproducible severity.
Note 1—It is well known that the critical step in the cracking mechanism is the development of an environment in the condensate film that occurs on the surface of the test specimen, and is rich in copper complex ions.
1.3 The severity of this test method depends upon the pH of the corrosive solution. In are given four different atmospheres to which the product may be exposed, and the appropriate pH of the solution to be used for the test, depending on the risk level associated with the intended application.
1.3.1 The appropriate pH value for the test shall be specified in the product specification, or as per established agreement between the supplier and purchaser, with respect to the alloy and its intended application.
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B858–95
Standard Test Method for
Determination of Susceptibility to Stress Corrosion
Cracking in Copper Alloys Using an Ammonia Vapor Test
This standard is issued under the fixed designation B 858; 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 (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
1.1 This test method describes a procedure that may be 2.1 ASTM Standards:
used to determine the presence of residual stresses which may B 154 Test Method for Mercurous Nitrate Test for Copper
lead to stress corrosion cracking of wrought copper alloy and Copper Alloys
products. This test method uses an ammonia atmosphere to D 1193 Specification for Reagent Water
simulateserviceconditionsunderwhichstresscorrosioncrack- 2.2 Other Documents:
ing may occur. ISO 6957 CopperAlloys—Ammonia Test for Stress Corro-
1.2 This test method is only suitable for products fabricated sion Resistance
from copper alloys that are known to be susceptible to stress
3. Terminology
corrosion cracking in ammonia vapor atmospheres. It is in-
3.1 Definitions:
tended to create an environmental condition of reproducible
severity, but it is well known that the critical step in the 3.1.1 applied stress—stress in a body as a result of appli-
cation of an external load.
cracking mechanism is the development of an environment in
the condensate film that occurs on the surface of the test 3.1.2 residual stress—stresses that remain within a body as
theresultofprocessing,whichmayincludeplasticdeformation
specimen, which is rich in copper complex ions.
1.3 This test method is a conversion of ISO 6957, “Copper or casting.
3.1.3 stress corrosion crack—spontaneous failure of metals
Alloys—Ammonia Test for Stress Corrosion Resistance.”
1.4 The severity of this test method depends upon the pH of by cracking under combined action of corrosion and stress,
residual or applied.
the corrosive solution. In Annex A1 are given four different
atmospheres to which the product may be exposed, and the
4. Summary of Test Method
appropriate pH of the solution to be used for the test,
4.1 The prepared test specimen is placed in a closed
depending on the risk level associated with the intended
container and exposed to ammonia vapor at ambient tempera-
application.
ture for 24 h. Upon removal from the test atmosphere, the test
1.4.1 TheappropriatepHvalueforthetestshallbespecified
specimen is examined for the presence of cracks.
in the product specification, or as per established agreement
between the supplier and purchaser, with respect to the alloy
5. Significance and Use
and its intended application.
5.1 This test method is an accelerated test to determine if a
1.5 The values stated in SI units are the standard.
copper alloy product in a specific stress condition will be
1.6 This standard does not purport to address all of the
susceptible to stress corrosion cracking when exposed to a
safety concerns, if any, associated with its use. It is the
particular atmospheric condition during service with the ap-
responsibility of the user of this standard to establish appro-
propriate risk level—see Annex A1. This test method is
priate safety and health practices and determine the applica-
generally intended to determine if a copper alloy product will
bility of regulatory limitations prior to use.
crack because of internal stresses when subjected to the test,
and is not intended for testing assemblies under applied stress.
If used for this purpose it shall be for information only and not
This test method is under the jurisdiction ofASTM Committee B05 on Copper
and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on
Methods of Test.
Current edition approved June 15, 1995. Published August 1995. Annual Book of ASTM Standards, Vol 02.01.
2 4
This test method is a conversion of ISO 6957 “CopperAlloys—Ammonia Test Annual Book of ASTM Standards, Vol 11.01.
for Stress Corrosion Resistance.”Additional background information is included in Available from American National Standards Institute, 11 W. 42nd St., 13th
Appendix X1. Floor, New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
B858–95
a cause for rejection of the assembly, its component parts, or peroxide solution may be added to the pickling solution (for
the original mill product. example, 20 to 30 mL of hydrogen peroxide solution per litre
of pickling solution).
6. Apparatus
9. Test Specimen Preparation
6.1 pH meter.
9.1 The test specimen shall be prescribed in the material
6.2 Closed vessel, such as a desiccator.
specification for the product or part being tested. In the event
6.3 Equipment for examining test pieces at 10 to 153
that a test specimen size is not prescribed in a given rod, wire,
magnification.
or tube specification, a full cross section having a minimum
7. Reagents and Materials
length of 152 mm shall be tested.
9.2 The presence of burrs on the test specimen may con-
7.1 Purity of Reagents—Reagent grade chemicals shall be
tribute to acceleration of stress corrosion cracking if not
used in all tests. Unless otherwise indicated, it is intended that
removed before the ammonia vapor test. The burrs shall be
all reagents conform to the specifications of the Committee on
removed by fine file or abrasive paper to facilitate this test.
Analytical Reagents of the American Chemical Society where
9.3 Degrease the test specimen using the clean organic
such specifications are available. Other grades may be used,
solvent or alkaline solution.
provided it is first ascertained that the reagent is of sufficiently
9.4 After degreasing, clean the test piece in the pickling
high purity to permit its use without lessening the accuracy of
solution and immediately thereafter thoroughly rinse it, first in
the determination.
cold running water, then in hot water, and finally, completely
7.2 Purity of Water—Unless otherwise indicated, references
dry it in a stream of warm air.
to water shall be understood to mean reagent water as defined
by Type IV or better, of Specification D 1193D 1193.
10. Test Procedure
7.3 Ammonium Chloride Solution (4N)—Dissolve 107 g of
10.1 Allow the dry test piece to reach the exposure tem-
ammonium chloride (NH Cl) in water and dilute to 500 mL.
perature specified below, and transfer it immediately to the
Store the solution in a closed vessel.
closed vessel (see 6.2) at the same temperature, and containing
7.4 Hydrogen Peroxide (H O ), 30 to 35 % technical grade.
2 2
the freshly prepared test solution at the specified pH value (see
(Warning—Hydrogen peroxide in high concentrations can
8.1).
cause severe skin burns.)
10.1.1 Suspend (or place) the test piece in such a way that
7.5 Sodium Hydroxide Solution (300 to 500 g/L)—Dissolve
the ammonia vapor has free access to all surfaces, not less than
300 to 500 g of sodium hydroxide (NaOH) into water and
50 mm above the test sol
...
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