ASTM B633-2007 Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel《铁和钢中锌电镀层用标准规范》.pdf

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1、Designation: B 633 07Standard Specification forElectrodeposited Coatings of Zinc on Iron and Steel1This standard is issued under the fixed designation B 633; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision

2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specification covers requirements for electr

3、odepos-ited zinc coatings applied to iron or steel articles to protectthem from corrosion. It does not cover electrodeposited zinc-coated steel wire or sheets (see Specification A 591/A 591Mfor sheets).1.2 The coatings are provided in four standard thicknessclasses (4.1), in the as-plated condition

4、or with one of threetypes of supplementary finish (4.2).1.3 High strength metals, unless otherwise specified, includ-ing high strength steels having a tensile strength greater than1700 MPa (247 ksi Rc46) shall not be electroplated.1.4 This standard does not purport to address all of thesafety concer

5、ns, 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 limitations prior to use.1.5 This standard has been revised to address RoHS re-quirements that seek to limit

6、the exposure of workers and thepublic from exposure to toxic metals. Additional types havebeen added to permit non-chromate passivate treatments to beused in replacement of hexavalent chromium.2. Referenced Documents2.1 ASTM Standards:2A 591/A 591M Specification for Steel Sheet, ElectrolyticZinc-Coa

7、ted, for Light Coating Weight Mass Applica-tions3B117 Practice for Operating Salt Spray (Fog) ApparatusB 183 Practice for Preparation of Low-Carbon Steel forElectroplatingB 201 Practice for Testing Chromate Coatings on Zinc andCadmium SurfacesB 242 Guide for Preparation of High-Carbon Steel forElect

8、roplatingB 254 Practice for Preparation of and Electroplating onStainless SteelB 320 Practice for Preparation of Iron Castings for Electro-platingB 322 Guide for Cleaning Metals Prior to ElectroplatingB 374 Terminology Relating to ElectroplatingB 487 Test Method for Measurement of Metal and OxideCoa

9、ting Thickness by Microscopical Examination of CrossSectionB 499 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB 504 Test Method for Measurement of Thickness of Me-tallic Coatings by the Coulometric MethodB 567 Test Method for

10、 Measurement of Coating Thicknessby the Beta Backscatter MethodB 568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB 571 Practice for Qualitative Adhesion Testing of MetallicCoatingsB 602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB 697 Guide for Selec

11、tion of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB 762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB 849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen EmbrittlementB 850 Guide for Post-Coating Treatments o

12、f Steel for Re-ducing the Risk of Hydrogen EmbrittlementD 2092 Guide for Preparation of Zinc-Coated (Galvanized)Steel Surfaces for PaintingF 1470 Guide for Fastener Sampling for Specified Mechani-cal Properties and Performance Inspection2.2 Military Standard:4MIL-STD-1312 Fastener Tests, Methods (Te

13、st 12)1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.08.04 on Soft Metals.Current edition approved Jan. 15, 2007. Published February 2007. Originallyapproved in 1978. Last previous edition appr

14、oved in 1998 as B 633 98e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from Standar

15、dization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 DefinitionsDefinitions of the terms

16、used in this speci-fication are in accordance with Terminology B 374.3.1.1 passivitefor the purpose of this specification, aconversion coating on zinc shall not contain hexavalent chro-mium.4. Classification4.1 ThicknessThe coating shall be provided in one of thefour thickness classes defined in Tab

17、le 1.4.2 FinishThe coating shall have one of the finish typesdefined in Table 2.5. Ordering Information5.1 When ordering the electroplating of articles, the pur-chaser shall state ASTM B 633, the date of issue, servicecondition number, and the Type (see 4.1, 4.2, and 7.1).5.2 If necessary, the purch

18、aser shall include on his partdrawings or purchase order the following:5.2.1 Basis metal alloy designation and ultimate tensilestrength of the steel,5.2.2 Thickness, if other than specified (4.1, 7.1),5.2.3 Location of significant surface (7.1.1, 7.1.2),5.2.4 Luster (7.3),5.2.5 Heat treatment except

19、ions (6.4, 6.5),5.2.6 Corrosion resistance test, if specified (9.3, 10.3),5.2.7 Hydrogen embrittlement test, if required (9.4, 10.4),including the tensile strength of the items,5.2.8 Sample size for inspection, if other than specified, and5.2.9 Supplementary requirements, if applicable (seeSupplemen

20、tary Requirement).6. Materials and Manufacture6.1 The coatings shall be non-alloyed zinc produced byelectrodeposition.6.2 Defects in the surface of the basis metal, such asscratches, porosity, pits, inclusions, cracks, roll marks, and diemarks, may adversely affect the appearance and performanceof c

21、oatings applied thereto despite the observance of the bestelectroplating practices. Accordingly, the electroplaters re-sponsibility for defects in the coating resulting from suchconditions shall be waived, except when he is the primecontractor supplying electroplated parts. In this event, the basism

22、etal shall be subjected to such polishing or buffing operationsas are necessary to yield deposits with the desired final lusterand appearance. To minimize problems of this sort, thespecifications covering the basis material on the item to beelectroplated shall contain appropriate limitations to such

23、 basismetal conditions.6.3 Cleaning of Basis MetalProper preparatory proce-dures and thorough cleaning of the basis metal are essential toensure satisfactory adhesion and corrosion resistance perfor-mance of the coating. It is recommended that the followingappropriate recommended practices and guide

24、s be used: B 183,B 242, B 254, B 320, and B 322.6.4 Pretreatment of Iron or Steel for the Purpose of Reduc-ing the Risk of Hydrogen EmbrittlementAll steel partshaving an ultimate tensile strength greater than 1000 MPa(31 HRC) and that have been machined, ground, cold formed,or cold straightened, sha

25、ll be heat treated for stress relief toreduce the risk of hydrogen embrittlement in the part beforeclean and electroplate processes. If these heat treatments arenot required, the purchaser shall specify in the orderinginformation their exception, (5.2.5). If the purchaser does notspecify an exceptio

26、n to heat treatment, then the plater shall useTable 1 in B 849 to determine the appropriate heat treatmentfor the steel based on its tensile strength.6.5 Post Coating Treatments of Iron and Steel for thePurpose of Reducing the Risk of Hydrogen EmbrittlementAllelectroplated steel parts having a tensi

27、le strength greater than1000 MPa (31 HRC) as well as surface hardened parts, shall bebaked to reduce the risk of hydrogen embrittlement. If theseheat treatments are not required, the purchaser shall specify inthe ordering information their exception (5.2.5). If the pur-chaser does not specify an exc

28、eption to heat treatment, then theplater shall use Table 1 in B 850 to determine the appropriateheat treatment for the steel based on its tensile strength. Thebaking treatment shall be done before the application of thesupplementary treatments and within4hofremoval from thelast process. Electroplate

29、d springs and other parts subject toflexure shall not be flexed before the hydrogen embrittlementrelief treatment. Baked parts shall not crack or fail by fracturewhen tested in accordance with 10.4.6.6 Reactivation TreatmentElectroplated surfaces passi-vated as a result of the baking operation shall

30、 be reactivatedbefore receiving a supplementary treatment.NOTE 1Surfaces should be activated as soon as possible followingbaking and handled carefully to avoid contamination and maintain anactive surface for post processing. Proprietary methods are available toprepare the surface or a 2% v/v sulfuri

31、c acid in deionized water or a 7-10g/l solution of sulfamic acid in deionized water can be used.6.7 Supplementary TreatmentsThe supplementary filmtreatment for Types II, III, V, and VI shall be in accordancewith Practice B 201 (see Notes 2 and 3). The treatmentrequired for conversion to Type IV shal

32、l be in accordance withGuide D 2092.NOTE 2The zinc surface is attacked by supplementary treatments,TABLE 1 Thickness Classes for CoatingsClassification Numberand ConversionCoating SuffixService ConditionThickness, minmFe/Zn 25 SC 4 (very severe) 25Fe/Zn 12 SC 3 (severe) 12Fe/Zn 8 SC 2 (moderate) 8Fe

33、/Zn 5 SC 1 (mild) 5TABLE 2 Finish Type and Corrosion Resistance RequirementsType Description Minimum Salt SprayhI As-plated without supplementary treatmentsII With colored chromate coatings 96III With colorless chromate conversion coatings 12IV With phosphate conversion coatingsV With colorless pass

34、ivate 72VI With colored passivate 120B633072thereby diminishing the amount of metallic zinc present. With ClassesFe/Zn25 and Fe/Zn13, this reduction is insignificant; but it is significantwith Fe/Zn8 and Fe/Zn5. Therefore, it is recommended that supplemen-tary treatments not be applied to zinc coati

35、ngs having a nominal thicknessless than 5 m.NOTE 3Although Types V and VI are technically not “chromate”films and they do not contain leachable hexavalent chromium ions, theyare supplemental coatings that render the active zinc surface passive andprovide added protection to the steel part.7. Coating

36、 Requirements7.1 ThicknessThe thickness shall be specified in accor-dance with 4.1 and 5.1. (see Note 2)7.1.1 Significant SurfacesSignificant surfaces are areaswhere minimum thicknesses to be met shall be designated onthe applicable drawing or by the provision of a suitably markedsample. Significant

37、 surfaces may be defined as those normallyvisible, directly or by reflection, which are essential to theappearance or serviceability of the article when assembled innormal position or which are the source of corrosion productsthat deface visible surfaces on the assembled article.7.1.2 Surfaces on wh

38、ich the specified thickness of depositcannot readily be controlled, such as threads, holes, deeprecesses, bases of angles, and similar areas, are normallyexempt from minimum thickness requirements, unless they arespecially designated as not exempt. When such areas aredesignated, and thus made subjec

39、t to minimum thicknessrequirements, the purchaser and the manufacturer shall recog-nize the necessity for either thicker deposits on other areas orfor special racking.NOTE 4The dimensional tolerance of most threaded articles, such asnuts, bolts, screws, and similar fasteners with complementary threa

40、ds,normally does not permit the application of a coating thickness muchgreater than 8.0 m. If heavier coatings are required, allowance for thedeposit buildup must be made during the manufacture of the threadedarticles.7.2 AdhesionThe adhesion of the coating shall be suchthat when examined in accorda

41、nce with 10.2, the coating shallnot show separation from the basis metal at the interface.7.3 LusterUnless otherwise specified by the purchaser, abright, semi-bright, or dull finish shall be acceptable.7.4 Corrosion Resistance Zinc coatings with Types II, III,V, and VI treatments shall show neither

42、corrosion products ofzinc nor basis metal corrosion products at the end of the testperiods describe in Table 2 when tested by continuous expo-sure to salt spray in accordance with 10.3. The appearance ofcorrosion products when examined with 20/20 eyesight atnormal reading distance shall be cause for

43、 rejection, except thatwhite corrosion products 6 mm or less from the edges ofspecimens shall not constitute failure. For corrosion resistancerequirements, see Table 2.7.5 WorkmanshipThe surface of the electroplated articleshall be uniform in appearance, free of visible coating defects,such as blist

44、ers, pits, roughness, nodules, burning, cracks, orunplated areas, and other defects that will affect the function ofthe coating. The coating shall not be stained or discolored.However, superficial staining that results from rinsing or slightdiscoloration resulting from any drying or baking operation

45、 torelieve hydrogen embrittlement, shall not be cause for rejec-tion. On articles in which a visible contact mark is unavoidable,its position shall be that chosen by the purchaser. The electro-plated article shall be clean and free of damage.8. Sampling8.1 The purchaser and producer are urged to emp

46、loy statis-tical process control in the coating process. Properly per-formed, statisitical process control will assure coated productsof satisfactory quality and will assure the amount of acceptanceinspection. The sampling plan used for the inspection of thequality coated article shall be agreed upo

47、n between thepurchaser and producer.8.1.1 When a collection of coated articles (inspection lot,see 8.2) is examined for compliance with the requirementsplaced on the articles, a relatively small number of the articles(sample) is selected at random and is inspected. The inspectionlot is then classifi

48、ed as complying with the requirements basedon the results of the inspection of the sample. The size of thesample and the criteria for compliance are determined by theapplication of statistics. The procedure is known as samplinginspection. Test Method B 602, Guide B 697, and Test MethodB 762 contain

49、sampling plans that are designed for samplinginspection of coatings.8.1.2 Test Method B 602 contains four sampling plans, threefor use with tests that are nondestructive and one when they aredestructive. Test Method B 602 provides a default plan if oneis not specified.8.1.3 Guide B 697 provides a large number of plans andalso gives guidance in the selection of a plan. Guide B 697provides a default plan if one is not specified.8.1.4 Test Method B 762 can be used only for coatingrequirements that have a numerical limit, such as coatingthickness. The test must y