1、Designation: B 858 06Standard Test Method forAmmonia Vapor Test for Determining Susceptibility toStress Corrosion Cracking in Copper Alloys1This standard is issued under the fixed designation B 858; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method describes a procedure to determine thepresence of residual stresses in
3、wrought copper alloy productsthat may lead to stress corrosion cracking. An ammonia vaporatmosphere is used as an accelerated test.1.2 This test method is only suitable for products fabricatedfrom copper alloys that are known to be susceptible to stresscorrosion cracking in ammonia vapor atmospheres
4、. It is in-tended to create an environmental condition of reproducibleseverity.NOTE 1It is well known that the critical step in the crackingmechanism is the development of an environment in the condensate filmthat occurs on the surface of the test specimen, and is rich in coppercomplex ions.1.3 The
5、severity of this test method depends upon the pH ofthe corrosive solution. In Annex A1 are given four differentatmospheres to which the product may be exposed, and theappropriate pH of the solution to be used for the test,depending on the risk level associated with the intendedapplication.1.3.1 The
6、appropriate pH value for the test shall be specifiedin the product specification, or as per established agreementbetween the supplier and purchaser, with respect to the alloyand its intended application.1.4 UnitsThe values stated in SI units are to be regardedas the standard. No other units of measu
7、rement are included inthis standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limi
8、tations prior to use.2. Referenced Documents2.1 ASTM Standards:2B 154 Test Method for Mercurous Nitrate Test for CopperAlloysB 846 Terminology for Copper and Copper AlloysD 1193 Specification for Reagent Water3. Terminology3.1 For definitions of terms related to copper and copperalloys, refer to Ter
9、minology B 846.3.2 Definitions:3.2.1 applied stress, nstress in a body as a result ofapplication of an external load.4. Summary of Test Method4.1 The prepared test specimen is placed in a closedcontainer and exposed to ammonia vapor with a specific pH atambient temperature for 24 h. Upon removal fro
10、m the testatmosphere, the test specimen is examined for the presence ofcracks.5. Significance and Use5.1 This test method is an accelerated test to determine if acopper alloy product will be susceptible to stress-corrosioncracking when exposed to a particular atmospheric conditionduring service with
11、 the appropriate risk levelsee Annex A1.5.1.1 This test method is generally intended to determine ifa copper alloy product will crack because of internal stresseswhen subjected to the test, and is not intended for testingassemblies under applied stress. If used for this purpose, it shallbe for infor
12、mation only and not a cause for rejection of theassembly, its component parts, or the original mill product.6. Apparatus6.1 pH meter.6.2 Closed vessel, such as a desiccator.1This test method is under the jurisdiction of ASTM Committee B05 on Copperand Copper Alloys and is the direct responsibility o
13、f Subcommittee B05.06 onMethods of Test.Current edition approved March 15, 2006. Published March 2006. Originallyapproved in 1995. Last previous edition approved in 2001 as B 858 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.o
14、rg. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*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 State
15、s.6.3 Equipment for examining test pieces at 103 to 153magnification.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of t
16、he American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, references
17、to water shall be understood to mean reagent water as definedby Type IV or better, of Specification D 1193.7.3 Ammonium Chloride Solution (4N)Dissolve 107 g ofammonium chloride (NH4Cl) in water and dilute to 500 mL.Store the solution in a closed vessel.7.4 Hydrogen Peroxide (H2O2), 30 to 35 % techni
18、cal grade.(WarningHydrogen peroxide in high concentrations cancause severe skin burns. Use of proper safety equipment isadvised.)7.5 Sodium Hydroxide Solution (300 to 500 g/L)Dissolve300 to 500 g of sodium hydroxide (NaOH) into water anddilute to 1 L. (WarningSodium hydroxide can cause chemi-cal bur
19、ns to the skin and eyes. Use of proper safety equipmentis advised.)7.6 A clean organic solvent or hot alkaline solution thatcontains no ammoniacal-type groups or substituents.7.7 Sulfuric Acid Solution (50 mL/L)Slowly add 50 mL ofconcentrated sulfuric acid (H2SO4) into water and dilute to 1 L.8. Tes
20、t Media8.1 Slowly add sodium hydroxide solution to ammoniumchloride solution to give a test solution with a pH valueappropriate to the intended application (see Annex A1). Main-tain the solution at ambient temperature and dilute with DIwater up to a volume of 1 L. Check the pH value with the pHmeter
21、 after dilution. Prepare the solution preferably in a fumehood in a laboratory using appropriate safe laboratory proce-dures and store it in a closed vessel. Before use, check the pHvalue again, and adjust if necessary.8.1.1 In the closed test vessel, the ratio of surface area oftest solution to air
22、 volume of the vessel above the solution shallbe a minimum of 20 cm2/L.8.2 The pickling solution for cleaning test pieces before andafter testing shall be 5 % sulfuric acid. If necessary, forcleaning test pieces after testing, a small amount of hydrogenperoxide solution may be added to the pickling
23、solution (forexample, 20 to 30 mL of hydrogen peroxide solution per litreof pickling solution).9. Test Specimen Preparation9.1 The test specimen size shall be prescribed in thespecification of the product or part being tested. In the eventthat a test specimen size is not prescribed in a given rod, w
24、ire,or tube specification, a full cross section having a minimumlength of 152 mm shall be tested.9.2 The presence of burrs on the test specimen may con-tribute to acceleration of stress corrosion cracking if notremoved before the ammonia vapor test. The burrs shall beremoved by fine file or abrasive
25、 paper to facilitate this test.9.3 Degrease the test specimen using the clean organicsolvent or alkaline solution.9.4 After degreasing, clean the test piece in the picklingsolution and immediately thereafter thoroughly rinse it, first incold running water, then in hot water, and finally, completelyd
26、ry it in a stream of warm air.10. Test Procedure10.1 Allow the dry test piece to reach the exposure tem-perature specified below, and transfer it immediately to theclosed vessel (see 6.2) at the same temperature, and containingthe freshly prepared test solution at the specified pH value (see8.1).10.
27、1.1 Suspend (or place) the test piece such that theammonia vapor has free access to all surfaces, not less than 50mm above the test solution surface.10.1.1.1 When placed on a porcelain support within the testvessel, the region of the test piece within 5 mm of the supportshall be disregarded when ins
28、pecting for cracks.10.1.1.2 The test piece shall be placed no less than 10 mmfrom the inside walls of the test vessel.10.1.1.3 When more than one test piece is placed in thevessel, the test pieces shall be no less than 10 mm apart.10.2 The volume of the test solution shall be at least 200 mLper squa
29、re decimeter of test piece surface. The exposuretemperature shall be between 20 and 30C and shall be keptconstant to within 61C during the test. In case of dispute, theexposure temperature shall be 25C 6 1C.10.3 The exposure time shall be 24 h.10.4 After exposure, remove the test piece from the clos
30、edvessel and immediately clean it in pickling solution for a fewminutes at ambient temperature (below 40C), or until thesurfaces of the test piece are sufficiently clean from corrosionproducts to allow observation of possible cracks. After rinsingin water and drying in warm air, examine the surface
31、of the testpiece for cracks at a magnification of 10 to 153.10.5 Before inspection, deform the test piece slightly bybending or flattening to open up fine cracks to make them moreeasily observable.10.6 Metallographic examination may be used to evaluatethe nature of any observed cracks.11. Test Repor
32、t11.1 The test report shall contain the following information:11.1.1 Sample identification,11.1.2 Reference to the test method used,11.1.3 The pH value used for the solution producing theammonia vapor atmosphere,3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society,
33、Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.B8580
34、6211.1.4 The number of replicate test pieces tested,11.1.5 The test results: cracks or no cracks (as required inthe appropriate product specification),11.1.6 Any other features of the material noted during thedetermination, and11.1.7 The date of the test.12. Precision and Bias12.1 No information is
35、presented about either the precisionor bias of this test method for determining susceptibility tostress corrosion cracking in copper alloys since the procedureis directed at a subjective nonquantitative visual interpretationof condition of the specimen and its relation to an applicableproduct specif
36、ication.13. Keywords13.1 ammonia test; copper alloys; residual stress; stresscorrosion; stress corrosion crackingANNEX(Mandatory Information)A1. REPRESENTATIVE pH VALUESA1.1 On the basis of the known correlation between thebehavior of test pieces in the ammonia vapor test and thebehavior of copper a
37、lloy products under service conditions, thefollowing pH values are considered as being representative ofatmospheres of different corrosiveness and corresponding todifferent safety requirements.A1.1.1 An appropriate risk level (pH value) shall be speci-fied in the product specification.Corrosiveness
38、of Atmosphere pH Value Safety RequirementLow HighLowIndoor atmosphere conditions 8.3 9.5ModerateIndoor atmosphere with risk of formation ofcondensation9.5 10.0Outdoor atmosphere, temperate climate 9.8 10.0HighAtmosphere with ammoniacal pollution, forexample in stables10.0 10.5APPENDIX(Nonmandatory I
39、nformation)X1. RATIONALE (COMMENTARY)X1.1 This test method was developed to address thedemand for a test method for determination of the presence ofresidual stresses in copper alloy products which may lead tostress corrosion cracking other than the mercurous nitrate test,Test Method B 154. Research
40、work performed by Mattsson, etal4validates the technical integrity of the test method.X1.2 This test method does not attempt to compare theeffectiveness of the test to other test methods, including themercurous nitrate test, Test Method B 154, nor does it attemptto quantify its relative effectivenes
41、s on various copper alloyproducts. These issues must be addressed on a case by casebasis, since such products and tests are specific for theirrespective requirements and applications.4Einar Mattsson, Rolf Holm, and Lars Hassel, “Ammonia Test for StressCorrosion of Copper Alloys.”B858063SUMMARY OF CH
42、ANGESCommittee B05 has identified the location of selected changes to this standard since the last issue (B 858 01)that may impact the use of this standard. (Approved March 15, 2006.)(1) Updated the Summary of Test Method section.(2) Updated the Test Procedure section.(3) Added “stress corrosion cra
43、cking” to the Keywords sec-tion.(4) Removed ISO 6957 from the Referenced Documentssection, and removed its reference within the text.(5) Removed the terms “residual stress” and “stress corrosioncrack” because they are in Terminology B 846.(6) Made general editorial modifications throughout thedocume
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47、ittee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B858064
