1、Designation: B489 85 (Reapproved 2013)Standard Practice forBend Test for Ductility of Electrodeposited andAutocatalytically Deposited Metal Coatings on Metals1This standard is issued under the fixed designation B489; the number immediately following the designation indicates the year oforiginal adop
2、tion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a test procedure for determining theductility of el
3、ectrodeposited and autocatalytically depositedcoatings on sheet or strip basis metals. The purpose of the testis to determine the resistance of metal coatings to crackingduring distortion.21.2 Test Methods E8 can be used if the coatings are tooductile and require mandrels too small to be practical.1
4、.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 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
5、-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B177 Guide for Engineering Chromium ElectroplatingD1193 Specification for Reagent WaterE8 Test Methods for Tension Testing of Metallic Materials3. Su
6、mmary of Practice3.1 The practice consists of bending a narrow strip of theelectroplated or coated article over a mandrel. An elongationmeasurement is obtained from the smallest diameter mandrelthat does not cause the coating to fracture.4. Significance and Use4.1 The routine measurement of the duct
7、ility of electrode-posited and autocatalytically deposited metal coatings can beuseful in process control, especially when the electroplatingprocess is used for decorative and engineering purposes.5. Apparatus5.1 Series of Mandrels, with diameters from 6 to 50 mm, in3-mm steps with lengths of 100 to
8、 150 mm so they can be heldin a vise.5.2 Micrometer, to measure the thickness of the test speci-mens.5.3 Guillotine Shears or other device to cut the specimens tosize.5.4 File or Grinder to remove burrs and to round or chamferedges.5.5 Vise, to hold mandrels.5.6 Magnifier, 10.6. Test Specimen6.1 Fla
9、t specimens, 10 mm wide, and not less than 150 mmlong, shall be cut from the electroplated or coated article if theshape permits, no closer than 25 mm from the edges. Guillotineshears are preferred, but any convenient method may be used.Basis metal thickness and temper shall be suitable to permitben
10、ding around the smallest diameter mandrel, if necessary.Low-carbon AISI 1010 to 1025 steel strip or sheet, 0.25 to 1.0mm thick is usually suitable. Basis metals that have lowductility can initiate cracks that can propagate through thecoatings.The procedure indicated in 6.2 shall then be followed.6.2
11、 When the shape is such that a test specimen cannot beobtained from the part, a test panel may be prepared ofappropriate basis metal, such as low-carbon steel (see 6.1),with the same coating system in the same baths.The panel shallbe sufficiently large to obtain several pieces after trimming 25mm fr
12、om the edges. The specimens shall be prepared inaccordance with 6.1. Brass or copper panels may be usedinstead of copper-electroplated zinc alloy panels.6.3 The long edges of the test pieces shall be rounded orchamfered by filing or grinding.1This practice is under the jurisdiction of ASTM Committee
13、 B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved Dec. 1, 2013. Published December 2013. Originallyapproved in 1968. Last previous edition approved in 2008 as B489 85 (2008)1.DOI: 10.1520/B0489-85R13.2For a discussi
14、on and theory for this test see Mohrnheim, A. F., “The Bend Testfor Measuring the Strain Limit of Surfaces,” Plating, Vol 50, 1963, pp. 1094 1099.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
15、 volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Procedure7.1 Place the largest mandrel in the vise. Bend the testspecimen, with the coating outwar
16、d, over the mandrel so that asthe bend progresses the test specimen will remain in contactwith the top of the mandrel. Continue bending with slow,steadily applied pressure until the two legs are parallel. If thereare no cracks visible under a 10 magnifier, repeat the test,using new specimens, on pro
17、gressively smaller-diametermandrels, until cracks appear across or through the coating.Take the preceding mandrel diameter as the value for theductility determination. If the coating is electrodepositedchromium, the specimens may require heating or aging toovercome temporary hydrogen embrittlement.
18、A procedure toovercome hydrogen embrittlement is covered in Guide B177.7.1.1 Small cracks not greater than 1.5 mm long, confined tothe edges of the test specimen do not signify failure.7.1.2 At times, no single crack may develop over the convexsurface. If jagged cracks, or a series of shorter cracks
19、 develop(excluding edges), they signify failure.7.2 In multiple coatings, cracking may occur in the outercoatings only. In the case of nickel, cracks may extend throughthe nickel to an intermediate copper layer or to the basis metal.Methods for determining this are provided in the Appendix. Apositiv
20、e test for copper or iron signifies failure.7.3 Except for very ductile coatings, the apparent ductility isan inverse function of the thickness. If the test is to be used toevaluate the electroplating or autocatalytic process by periodi-cally testing the ductility of coatings produced by the process
21、,all specimens used must have approximately the same coatingand total thickness.8. Calculation8.1 Determine the elongation as follows:E 5 100T/D1T!where:E = percent elongation,T = total thickness of the basis metal and deposit, andD = diameter of the mandrel.NOTE 1To calculate percent elongation, E,
22、 the dimensions of T and Dmust be identical.9. Precision and Bias9.1 This practice is a useful one for routine control of theductility of metallic coatings. The largest source of error is inthe detection of crack initiation. The precision and bias for thispractice have not been statistically determi
23、ned.10. Keywords10.1 autocatalytic deposits; ductility tests; electrodepositsAPPENDIX(Nonmandatory Information)X1. COPPER AND IRON DETECTIONSPOT TEST TECHNIQUEX1.1 ApparatusX1.1.1 Spot Test Plate.X1.1.2 Dropping Pipets (Medicine Droppers).X1.1.3 Wash Bottle.X1.1.4 Glass Stirring Rod.X1.2 ReagentsX1.
24、2.1 The solutions shall be made with water conformingto Specification D1193, Type IV.X1.2.2 Acetic Acid MixturePrepare the mixture by addingto 45 mL of glacial acetic acid 5 mL of wetting agent, such as1 % solution of sodium lauryl sulfate.X1.2.3 Hydrogen PeroxideUse 30 volume % solution.X1.2.4 Zinc
25、 Acetate SolutionPrepare the zinc acetatesolution by using 1 mass % of ASC reagent grade material.X1.2.5 Ammonium Mercuric Thiocyanate SolutionAdd 8g of ASC reagent grade mercuric chloride and9gofASCreagent grade ammonium thiocyanate to 100 mL of water.X1.2.6 Nitric Acid (1+4)Add 1 part of concentra
26、ted nitricacid (HNO3, sp gr 1.42) to 4 parts of water by volume.X1.2.7 Potassium Thiocyanate SolutionUse a 10 mass %solution.X1.3 Copper Detection in the Presence of Nickel andChromiumX1.3.1 Using a dropping pipet, apply 1 drop of the aceticacid mixture and 1 drop of hydrogen peroxide to the bent an
27、dcracked surface. Permit the solution to remain for about 1 to 2min, avoiding its contact with the cut edges.X1.3.2 Transfer the drop of reagent from the test part witha pipet to a cavity in the spot test plate. Wash the test spot witha drop of water, and add the wash solution to the liquid in thesp
28、ot plate.X1.3.3 Add 1 drop of zinc acetate solution and 1 drop ofammonium mercuric thiocyanate solution to the solution in thespot plate cavity.X1.3.4 Gently agitate the spot plate or stir the solution. Aviolet colored precipitate indicates the presence of copper.X1.4 Iron Detection in the Presence
29、of Chromium,Nickel, or CopperX1.4.1 Apply 1 drop of HNO3(1+4) to the bent surface tobe tested.B489 85 (2013)2X1.4.2 Allow the acid to remain in contact with the surfacefor about 1 min.X1.4.3 Transfer the drop of HNO3with a dropping pipet toa cavity in the spot plate. At no time should the acid come
30、incontact with the cut edges.X1.4.4 Add 1 drop of potassium thiocyanate solution to thesolution in the spot plate cavity.X1.4.5 Gently agitate the spot or stir the solution. Theappearance of a blood red color indicates iron.ASTM International takes no position respecting the validity of any patent r
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32、ny time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments
33、will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by
34、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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).B489 85 (2013)3
