1、Designation: B633 15Standard Specification forElectrodeposited Coatings of Zinc on Iron and Steel1This standard is issued under the fixed designation B633; 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 () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This specification covers material and process
3、require-ments for electrodeposited zinc coatings applied to iron or steelarticles to protect them from corrosion.1.2 The coatings are provided in four standard thicknessclasses (4.1), in the as-plated condition or with one of fivetypes of supplementary finishes (4.2).1.3 High strength metals, unless
4、 otherwise specified, includ-ing high strength steels having a tensile strength greater than1700 MPa (247 ksi, 46HRC) shall not be electroplated.1.4 It does not cover continuous processes for electrodepos-ited zinc coated steel wire or sheets (see Specification A591/A591M for sheets.)1.5 It may be u
5、sed for fasteners but specific specificationshave been developed for manufacturing fasteners in CommitteeF16 which may be more applicable (see Specifications F1941and F1941M.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.
6、7 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 limitations prior to use.1.8 This standard
7、 has been revised to address RoHS re-quirements that seek to limit the exposure of workers and thepublic from exposure to toxic metals. Additional types V and VIhave been added to permit non-chromate passivate treatmentsto be used in replacement of hexavalent chromium.2. Referenced Documents2.1 ASTM
8、 Standards:2A591/A591M Specification for Steel Sheet, ElectrolyticZinc-Coated, for Light Coating Weight Mass Applica-tions (Withdrawn 2005)3B117 Practice for Operating Salt Spray (Fog) ApparatusB183 Practice for Preparation of Low-Carbon Steel forElectroplatingB201 Practice for Testing Chromate Coat
9、ings on Zinc andCadmium SurfacesB242 Guide for Preparation of High-Carbon Steel for Elec-troplatingB254 Practice for Preparation of and Electroplating onStainless SteelB320 Practice for Preparation of Iron Castings for Electro-platingB322 Guide for Cleaning Metals Prior to ElectroplatingB374 Termino
10、logy Relating to ElectroplatingB487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement
11、of Thickness of Metal-lic Coatings by the Coulometric MethodB567 Test Method for Measurement of Coating Thicknessby the Beta Backscatter MethodB568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB571 Practice for Qualitative Adhesion Testing of MetallicCoatings1This specificati
12、on is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.06 on Soft Metals.Current edition approved Dec. 1, 2015. Published December 2015. Originallyapproved in 1978. Last previous edition approved in 2013 as B633 13. DO
13、I:10.1520/B0633-15.2For 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.3The last approved version of this histori
14、cal standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1B602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB697 Guide for Selection of Sampling Plans for Inspectionof Electrodepo
15、sited Metallic and Inorganic CoatingsB748 Test Method for Measurement of Thickness of Metal-lic Coatings by Measurement of Cross Section with aScanning Electron MicroscopeB762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB849 Specification for Pre-Treatments of Iron or Steel fo
16、rReducing Risk of Hydrogen EmbrittlementB850 Guide for Post-Coating Treatments of Steel for Reduc-ing the Risk of Hydrogen EmbrittlementD2092 Guide for Preparation of Zinc-Coated (Galvanized)Steel Surfaces for Painting (Withdrawn 2008)3F1470 Practice for Fastener Sampling for Specified Me-chanical P
17、roperties and Performance InspectionF1941 Specification for Electrodeposited Coatings onThreaded Fasteners (Metric) F1941_F1941MF1941M Specification for Electrodeposited Coatings onThreaded Fasteners (Metric) (Withdrawn 2015)32.2 Military Standard:4MIL-STD-1312 Fastener Tests, Methods (Test 12)3. Te
18、rminology3.1 Definitions:3.1.1 Definitions of the terms used in this specification arein accordance with Terminology B374.3.1.2 passivatefor the purpose of this specification, aconversion coating on zinc shall not contain hexavalent chro-mium.4. Classification4.1 ThicknessThe coating shall be provid
19、ed in one of thefour thickness classes defined in Table 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 B633, the date of issue, servicecondition number, and the Type
20、 (see 4.1, 4.2, and 7.1).5.2 If necessary, the purchaser 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
21、.1.2),5.2.4 Luster (7.3),5.2.5 Exceptions to stress relief heat treatment prior toplating, (6.4),5.2.6 Exception to Hydrogen Embrittlement Relief afterplating, (6.5).5.2.7 Corrosion resistance test, if specified (9.3, 10.3),5.2.8 Hydrogen embrittlement test, if required (9.4, 10.4),including the ten
22、sile strength of the items,5.2.9 Sample size for inspection, if other than specified, and5.2.10 Supplementary requirements, if applicable (seeSupplementary Requirement).6. Materials and Manufacture6.1 The coatings shall be non-alloyed zinc produced byelectrodeposition.6.2 Defects in the surface of t
23、he basis metal, such asscratches, porosity, pits, inclusions, cracks, roll marks, and diemarks, may adversely affect the appearance and performanceof coatings applied thereto despite the observance of the bestelectroplating practices. Accordingly, the electroplaters re-sponsibility for defects in th
24、e coating resulting from suchconditions shall be waived, except when he is the primecontractor supplying electroplated parts. In this event, the basismetal shall be subjected to such polishing or buffing operationsas are necessary to yield deposits with the desired final lusterand appearance. To min
25、imize problems of this sort, thespecifications covering the basis material on the item to beelectroplated shall contain appropriate limitations to such basismetal conditions.6.3 Cleaning of Basis MetalProper preparatory proce-dures and thorough cleaning of the basis metal are essential toensure sati
26、sfactory adhesion and corrosion resistance perfor-mance of the coating. It is recommended that the followingappropriate recommended practices and guides be used: B183,B242, B254, B320, and B322.6.4 Pretreatment of Iron or Steel for the Purpose of Reduc-ing the Risk of Hydrogen EmbrittlementAll steel
27、 parts havingan ultimate tensile strength greater than 1000 MPa (31 HRC)and that have been machined, ground, cold formed, or coldstraightened, shall be heat treated for stress relief to reduce therisk of hydrogen embrittlement in the part before clean andelectroplate processes. If these heat treatme
28、nts are not required,4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.TABLE 1 Thickness Classes for CoatingsClassification Numberand ConversionCoating SuffixService ConditionThickness, minmFe/Zn
29、25 SC 4 (very severe) 25Fe/Zn 12 SC 3 (severe) 12Fe/Zn 8 SC 2 (moderate) 8Fe/Zn 5 SC 1 (mild) 5TABLE 2 Finish Type and Corrosion Resistance RequirementsType Description Minimum Salt SprayhI As-plated without supplementarytreatmentsII With colored chromate coatings 96III With colorless chromateconver
30、sion coatings12IV With phosphate conversioncoatingsV With colorless passivate 72VI With colored passivate 120B633 152the purchaser shall specify in the ordering information theirexception, (5.2.5). If the purchaser does not specify an excep-tion to heat treatment, then the plater shall use Table 1 i
31、n B849to determine the appropriate heat treatment for the steel basedon 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 tensile strength greater than1000 MPa (31 HRC) as well as surf
32、ace 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 exception to heat treatment, then theplater shall use Table
33、1 in B850 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. Electroplated springs and other parts subject toflexure shall not be f
34、lexed 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 be reactivatedbefore receiving a supplementary treatment.
35、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 sulfuric acid in deionized water or a 7-10g/L solution of sulfami
36、c 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 B201 (see Notes 2 and 3). The treatment requiredfor conversion to Type IV shall be in accordance with GuideD2092.NOTE 2The zinc surface i
37、s attacked by supplementary treatments,thereby diminishing the amount of metallic zinc present. With ClassesFe/Zn25 and Fe/Zn12, 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 coatings h
38、aving a nominal thicknessless than 5 m.NOTE 3Although Types V and VI are technically not “chromate” filmsand they do not contain leachable hexavalent chromium ions, they aresupplemental coatings that render the active zinc surface passive andprovide added protection to the steel part.7. Coating Requ
39、irements7.1 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 surf
40、aces 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 which t
41、he 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 subject to
42、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 threads,no
43、rmally 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 accordance w
44、ith 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 ResistanceZinc coatings with Types II, III,V, and VI treatments shall show neither corros
45、ion 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 rejec
46、tion, 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 blisters, p
47、its, 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 torel
48、ieve 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 employ st
49、atis-tical process control in the coating process. Properlyperformed, statisitical process control will assure coated prod-ucts of satisfactory quality and will assure the amount ofacceptance inspection. The sampling plan used for the inspec-tion of the quality coated article shall be agreed upon betweenthe purchaser 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. Th
