1、Designation: B633 13Standard 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 material and process requi
3、re-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 othe
4、rwise 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 used f
5、or 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.1.7 Thi
6、s 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 has
7、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 Stan
8、dards: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Specification for Steel Sheet, ElectrolyticZinc-Coated, for Light Coating Weight Mass Applica-tions (Withdrawn 2005)3B117 Practice for Operating Salt Spray (Fog) ApparatusB183 Practice for Preparation of Low-Carbon Steel forElectroplatingB201 Practice for Testing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 Coatings
9、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 Terminology
10、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 of Th
11、ickness 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 specification is
12、 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 May 15, 2013. Published June 2013. Originallyapproved in 1978. Last previous edition approved in 2011 as B633 11. DOI:10.1520
13、/B0633-13.2For 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 historical stand
14、ard 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 Electrodeposited Met
15、allic and Inorganic CoatingsB762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen EmbrittlementB850 Guide for Post-Coating Treatments of Steel for Reduc-ing the Risk of Hydrogen EmbrittlementD2092 G
16、uide for Preparation of Zinc-Coated (Galvanized)Steel Surfaces for Painting (Withdrawn 2008)3F1470 Practice for Fastener Sampling for Specified Me-chanical Properties and Performance InspectionF1941 Specification for Electrodeposited Coatings onThreaded Fasteners (Unified Inch Screw Threads (UN/UNR)
17、F1941M Specification for Electrodeposited Coatings onThreaded Fasteners (Metric)2.2 Military Standard:4MIL-STD-1312 Fastener Tests, Methods (Test 12)3. Terminology3.1 Definitions:3.1.1 Definitions of the terms used in this specification arein accordance with Terminology B374.3.1.2 passivatefor the p
18、urpose 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 FinishThe coating shall have one of the finish typesdefined in Table 2.5. Ordering I
19、nformation5.1 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 include on his partdrawings or purchase order the following:5.2.1 Basis metal alloy
20、 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 treatment prior toplating, (6.4),5.2.6 Exception to Hydrogen Embrittlement Relief
21、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 other than specified, and5.2.10 Supplementary requirements, if applicable (seeSupp
22、lementary 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 performanc
23、eof 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 when he is the primecontractor supplying electroplated parts. In this event, the b
24、asismetal 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
25、 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 coating. It is recommended that the followingappropriate recommended practices and
26、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 parts havingan ultimate tensile strength greater than 1000 MPa (31 HRC)and that have been machined, ground, cold formed, or coldstraightened, sha
27、ll be heat treated for stress relief to reduce therisk of hydrogen embrittlement in the part before clean andelectroplate processes. If these heat treatments are not required,the purchaser shall specify in the ordering information their4Available from Standardization Documents Order Desk, DODSSP, Bl
28、dg. 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 25 SC 4 (very severe) 25Fe/Zn 12 SC 3 (severe) 12Fe/Zn 8 SC 2 (moderate) 8Fe/Zn 5 SC
29、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 chromateconversion coatings12IV With phosphate conversioncoatingsV With colorless passivate 72VI Wi
30、th colored passivate 120B633 132exception, (5.2.5). If the purchaser does not specify an excep-tion to heat treatment, then the plater shall use Table 1 in B849to determine the appropriate heat treatment for the steel basedon its tensile strength.6.5 Post Coating Treatments of Iron and Steel for the
31、Purpose of Reducing 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 spec
32、ify 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 1 in B850 to determine the appropriateheat treatment for the steel based on its tensile strength. Thebaking treatment shall be done before the app
33、lication of thesupplementary 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 Re
34、activation TreatmentElectroplated 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
35、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 sulfamic acid in deionized water can be used.6.7 Supplementary TreatmentsThe supplementary filmtreatment for Types II, III, V, and VI shall be in accorda
36、ncewith 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 amount of metallic zinc present. With ClassesFe/Zn25 and Fe/Zn12, this reduction is
37、 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 and VI are technically not “chromate” filmsand they do not contain leachable hexaval
38、ent chromium ions, they aresupplemental 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-dance with 4.1 and 5.1 (see Note 2).7.1.1 Significant SurfacesSignificant surfaces
39、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 reflection, which are essential to theappearance or serviceability of the article whe
40、n 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, such as threads, holes, deeprecesses, bases of angles, and similar areas, are norma
41、llyexempt 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 manufacturer shall recog-nize the necessity for either thicker deposits on other areas orfor
42、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 muchgreater than 8.0 m. If heavier coatings are required, allowance for thedeposit b
43、uildup 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 metal at the interface.7.3 LusterUnless otherwise specified by the purchaser, abrigh
44、t, semi-bright, or dull finish shall be acceptable.7.4 Corrosion ResistanceZinc coatings with Types II, III,V, and VI treatments shall show neither 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 sa
45、lt 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 the edges ofspecimens shall not constitute failure. For corrosion resistancerequiremen
46、ts, 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, and other defects that will affect the function ofthe coating. The coating shall not b
47、e 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. On articles in which a visible contact mark is unavoidable,its position shall be t
48、hat 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. Properlyperformed, statisitical process control will assure coated prod-ucts of satisfactory qu
49、ality 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. The inspectionlot is then classified as complying with the requirements basedon the results of the inspection of the sample. The size of thesample
