1、Designation: B489 85 (Reapproved 2018)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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDev
6、elopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3B177 Guide for Engineering Chromium ElectroplatingD1193 Specification for Reagent WaterE8 Test Methods for Ten
7、sion Testing of Metallic Materials3. Summary 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 Use
8、4.1 The routine measurement of the ductility 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
9、mm, in3-mm steps with lengths of 100 to 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.
10、6 Magnifier, 10.6. Test Specimen6.1 Flat 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 an
11、d temper shall be suitable to permitbending 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 indi
12、cated in 6.2 shall then be followed.6.2 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 shall1This practice is under the ju
13、risdiction of ASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved Aug. 1, 2018. Published August 2018. Originallyapproved in 1968. Last previous edition approved in 2008 as B489 85 (2013).DOI: 10.1520/B0
14、489-85R18.2For a discussion 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 Ann
15、ual Book of ASTMStandards 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 StatesThis international standard was developed in accordance with internationally
16、recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1be sufficiently large to obtain several pieces after trimmi
17、ng 25mm from 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.7. Procedure7.1 Place the largest mandrel in the
18、 vise. Bend the testspecimen, with the coating outward, 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 m
19、agnifier, repeat the test,using new specimens, on progressively 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 o
20、r aging toovercome temporary hydrogen embrittlement. 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 convexsur
21、face. If jagged cracks, or a series of shorter cracks 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 de
22、termining this are provided in the Appendix. Apositive 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 test
23、ing the ductility of coatings produced by the process,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
24、the mandrel.NOTE 1To calculate percent elongation, E, 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
25、 for thispractice have not been statistically determined.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 W
26、ash Bottle.X1.1.4 Glass Stirring Rod.X1.2 ReagentsX1.2.1 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
27、Hydrogen PeroxideUse 30 volume % solution.X1.2.4 Zinc 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
28、water.X1.2.6 Nitric Acid (1+4)Add 1 part of concentrated 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 m
29、ixture and 1 drop of hydrogen peroxide to the bent andcracked 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 wa
30、ter, and add the wash solution to the liquid in thespot 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 pr
31、esence of copper.B489 85 (2018)2X1.4 Iron Detection in the Presence of Chromium,Nickel, or CopperX1.4.1 Apply 1 drop of HNO3(1+4) to the bent surface tobe tested.X1.4.2 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 cavit
32、y in the spot plate. At no time should the acid come 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 take
33、s no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own res
34、ponsibility.This standard is subject to revision at any 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 address
35、ed to ASTM International Headquarters. Your comments 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
36、 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 85 (2018)3
