1、Designation: B633 11Standard 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 Department of Defense.1. Scope1.1 This specification covers requirements for electrode
3、pos-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 A591/A591M forsheets).1.2 The coatings are provided in four standard thicknessclasses (4.1), in the as-plated condition or wi
4、th 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 The values stated in SI units shall be regarded asstandard.1.5 This st
5、andard 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.1.6 This standard has been
6、 revised to address RoHS re-quirements that seek to limit 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:2A591/A
7、591M Specification for Steel Sheet, ElectrolyticZinc-Coated, for Light Coating Weight Mass Applica-tions3B117 Practice for Operating Salt Spray (Fog) ApparatusB183 Practice for Preparation of Low-Carbon Steel forElectroplatingB201 Practice for Testing Chromate Coatings on Zinc andCadmium SurfacesB24
8、2 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 Terminology Relating to ElectroplatingB487
9、 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of CrossSectionB499 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement of Thickness of Me-tallic Coating
10、s 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 MetallicCoatingsB602 Test Method for Attribute Sampling of Metalli
11、c andInorganic CoatingsB697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen Embrittlement
12、B850 Guide for Post-Coating Treatments of Steel for Re-ducing the Risk of Hydrogen EmbrittlementD2092 Guide for Preparation of Zinc-Coated (Galvanized)Steel Surfaces for Painting3F1470 Practice for Fastener Sampling for Specified Me-chanical Properties and Performance Inspection1This specification i
13、s 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 Oct. 1, 2011. Published October 2011. Originallyapproved in 1978. Last previous edition approved in 2007 as B633 07. DOI:
14、10.1520/B0633-11.2For 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. The last approved version of thi
15、s historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.2 Military Standard:4MIL-STD-1312 Fastener Tests, Methods (Test 12)3. Terminology3.1 DefinitionsDefinitions of the terms used in thi
16、s speci-fication are in accordance with Terminology B374.3.1.1 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 Table 1.4.2 Fin
17、ishThe 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 (see 4.1, 4.2, and 7.1).5.2 If necessary, the purchaser shall in
18、clude 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 Exceptions to stress relief heat t
19、reatment 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 tensile strength of the items,5.2.9 Sample size for inspection, if o
20、ther 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 the basis metal, such asscratches, porosity, pits, inclusions, cra
21、cks, 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 the coating resulting from suchconditions shall be waived, except w
22、hen 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 minimize problems of this sort, thespecifications covering the basis
23、 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 satisfactory adhesion and corrosion resistance perfor-mance of the co
24、ating. 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 partshaving an ultimate tensile strength greater than 1000 MPa(3
25、1 HRC) and that have been machined, ground, cold formed,or cold straightened, shall 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 orderingi
26、nformation their exception, (5.2.5). If the purchaser does notspecify an exception to heat treatment, then the plater shall useTable 1 in B849 to determine the appropriate heat treatment forthe steel based on its tensile strength.6.5 Post Coating Treatments of Iron and Steel for thePurpose of Reduci
27、ng the Risk of Hydrogen EmbrittlementAllelectroplated steel parts having a tensile 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 orderin
28、g information their exception (5.2.5). If the pur-chaser does not specify an exception to heat treatment, then theplater shall use Table 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 thesu
29、pplementary treatments and within4hofremoval from thelast process. Electroplated 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 Treatm
30、entElectroplated surfaces passi-vated as a result of the baking operation shall 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 processi
31、ng. Proprietary methods are available to4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.TABLE 1 Thickness Classes for CoatingsClassification Numberand ConversionCoating SuffixService ConditionTh
32、ickness, minmFe/Zn 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 supplementary treatmentsII With colored chromate coatings 96III With colo
33、rless chromate conversion coatings 12IV With phosphate conversion coatingsV With colorless passivate 72VI With colored passivate 120B633 112prepare the surface or a 2% v/v sulfuric acid in deionized water or a 7-10g/l solution of sulfamic acid in deionized water can be used.6.7 Supplementary Treatme
34、ntsThe 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 is attacked by supplementary treatments,thereby diminishing the
35、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 coatings having a nominal thicknessless than 5 m.NOTE 3Although Types V a
36、nd 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 Requirements7.1 ThicknessThe thickness shall be specified in accor-
37、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 surfaces may be defined as those normallyvisible, directly or by re
38、flection, 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 the specified thickness of depositcannot readily be controlled,
39、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 minimum thicknessrequirements, the purchaser and the manufactur
40、er 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,normally does not permit the application of a coating thickness m
41、uchgreater 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 with 10.2, the coating shallnot show separation from the basis m
42、etal 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 corrosion products ofzinc nor basis metal corrosion products at the
43、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 rejection, except thatwhite corrosion products 6 mm or less from th
44、e 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, pits, roughness, nodules, burning, cracks, orunplated areas, an
45、d 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 torelieve hydrogen embrittlement, shall not be cause for rejec-tion
46、. 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 statis-tical process control in the coating process. Properly pe
47、r-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 upon between thepurchaser and producer.8.1.1 When a collection of coate
48、d 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 classified as complying with the requirements basedon the results of the ins
49、pection 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 B602, Guide B697, and Test MethodB762 contain sampling plans that are designed for samplinginspection of coatings.8.1.2 Test Method B602 contains four sampling plans, threefor use with tests that are nondestructive and one when they aredestructive. Test Method B602 provides a default plan if one isnot specified.8.1.3 Guide B697 provides a large number of plans and alsogives gu
