ASTM B858-06(2012)
(Test Method)Standard Test Method for Ammonia Vapor Test for Determining Susceptibility to Stress Corrosion Cracking in Copper Alloys
Standard Test Method for Ammonia Vapor Test for Determining Susceptibility to Stress Corrosion Cracking in Copper Alloys
SIGNIFICANCE AND USE
This test method is an accelerated test to determine if a copper alloy product will be susceptible to stress-corrosion cracking when exposed to a particular atmospheric condition during service with the appropriate risk levelsee Annex A1.
This test method is generally intended to determine if a copper alloy product will 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 a cause for rejection of the assembly, its component parts, or the original mill product.
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 Annex A1 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 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 − 06 (Reapproved 2012)
Standard Test Method for
Ammonia Vapor Test for Determining Susceptibility to
Stress Corrosion Cracking in Copper Alloys
This standard is issued under the fixed designation B858; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 ASTM Standards:
1.1 This test method describes a procedure to determine the
B154Test Method for Mercurous Nitrate Test for Copper
presence of residual stresses in wrought copper alloy products
Alloys
that may lead to stress corrosion cracking.An ammonia vapor
B846Terminology for Copper and Copper Alloys
atmosphere is used as an accelerated test.
D1193Specification for Reagent Water
1.2 This test method is only suitable for products fabricated
3. Terminology
from copper alloys that are known to be susceptible to stress
corrosion cracking in ammonia vapor atmospheres. It is in-
3.1 For definitions of terms related to copper and copper
tended to create an environmental condition of reproducible
alloys, refer to Terminology B846.
severity.
3.2 Definitions:
3.2.1 applied stress, n—stress in a body as a result of
NOTE 1—It is well known that the critical step in the cracking
mechanism is the development of an environment in the condensate film application of an external load.
that occurs on the surface of the test specimen, and is rich in copper
complex ions.
4. Summary of Test Method
1.3 TheseverityofthistestmethoddependsuponthepHof 4.1 The prepared test specimen is placed in a closed
the corrosive solution. In Annex A1 are given four different container and exposed to ammonia vapor with a specific pH at
ambient temperature for 24 h. Upon removal from the test
atmospheres to which the product may be exposed, and the
atmosphere, the test specimen is examined for the presence of
appropriate pH of the solution to be used for the test,
cracks.
depending on the risk level associated with the intended
application.
5. Significance and Use
1.3.1 TheappropriatepHvalueforthetestshallbespecified
5.1 This test method is an accelerated test to determine if a
in the product specification, or as per established agreement
copper alloy product will be susceptible to stress-corrosion
between the supplier and purchaser, with respect to the alloy
cracking when exposed to a particular atmospheric condition
and its intended application.
during service with the appropriate risk level—see AnnexA1.
1.4 Units—The values stated in SI units are to be regarded
5.1.1 This test method is generally intended to determine if
asstandard.Nootherunitsofmeasurementareincludedinthis
a copper alloy product will crack because of internal stresses
standard.
when subjected to the test, and is not intended for testing
assembliesunderappliedstress.Ifusedforthispurpose,itshall
1.5 This standard does not purport to address all of the
be for information only and not a cause for rejection of the
safety concerns, if any, associated with its use. It is the
assembly, its component parts, or the original mill product.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
6. Apparatus
bility of regulatory limitations prior to use.
6.1 pH meter.
6.2 Closed vessel, such as a desiccator.
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2012. Published August 2012. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2006 as B858 – 06. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/B0858-06R12. the ASTM website.
*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
B858 − 06 (2012)
6.3 Equipment for examining test pieces at 10× to 15× 9. Test Specimen Preparation
magnification.
9.1 The test specimen size shall be prescribed in the
specification of the product or part being tested. In the event
7. Reagents and Materials
that a test specimen size is not prescribed in a given rod, wire,
7.1 Purity of Reagents—Reagent grade chemicals shall be
or tube specification, a full cross section having a minimum
used in all tests. Unless otherwise indicated, it is intended that
length of 152 mm shall be tested.
all reagents conform to the specifications of the Committee on
9.2 The presence of burrs on the test specimen may con-
Analytical Reagents of theAmerican Chemical Society where
tribute to acceleration of stress corrosion cracking if not
such specifications are available. Other grades may be used,
removed before the ammonia vapor test. The burrs shall be
provided it is first ascertained that the reagent is of sufficiently
removed by fine file or abrasive paper to facilitate this test.
high purity to permit its use without lessening the accuracy of
the determination. 9.3 Degrease the test specimen using the clean organic
solvent or alkaline solution.
7.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water as defined 9.4 After degreasing, clean the test piece in the pickling
by Type IV or better, of Specification D1193. solution and immediately thereafter thoroughly rinse it, first in
cold running water, then in hot water, and finally, completely
7.3 Ammonium Chloride Solution (4N)—Dissolve 107 g of
dry it in a stream of warm air.
ammonium chloride (NH Cl) in water and dilute to 500 mL.
Store the solution in a closed vessel.
10. Test Procedure
7.4 Hydrogen Peroxide (H O ),30to35%technicalgrade.
2 2
10.1 Allow the dry test piece to reach the exposure tem-
(Warning—Hydrogen peroxide in high concentrations can
perature specified below, and transfer it immediately to the
cause severe skin burns. Use of proper safety equipment is
closedvessel(see6.2)atthesametemperature,andcontaining
advised.)
thefreshlypreparedtestsolutionatthespecifiedpHvalue(see
7.5 Sodium Hydroxide Solution (300 to 500 g/L)—Dissolve
8.1).
300 to 500 g of sodium hydroxide (NaOH) into water and
10.1.1 Suspend (or place) the test piece such that the
dilute to 1 L. (Warning—Sodium hydroxide can cause chemi-
ammonia vapor has free access to all surfaces, not less than 50
cal burns to the skin and eyes. Use of proper safety equipment
mm above the test solution surface.
is advised.)
10.1.1.1 When placed on a porcelain support within the test
7.6 A clean o
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