1、Designation: F 2329 05Standard Specification forZinc Coating, Hot-Dip, Requirements for Application toCarbon and Alloy Steel Bolts, Screws, Washers, Nuts, andSpecial Threaded Fasteners1This standard is issued under the fixed designation F 2329; the number immediately following the designation indica
2、tes the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements
3、for hot-dipzinc coating applied to carbon steel and alloy steel bolts,screws, washers, nuts, and special threaded fasteners appliedby the hot-dip coating process. Nails and rivets are notincluded in this specification.1.2 It is intended to be applicable to fasteners that arecentrifuged or otherwise
4、handled to remove excess galvanizingbath metal (free zinc).1.3 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-bi
5、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 153/A 153M Specification for Zinc Coating (Hot-Dip) onIron and Steel HardwareA 563 Specification for Carbon and Alloy Steel NutsB 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopi
6、cal Examination of aCross Section.E 376 Practice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) Exami-nation MethodsF 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, and RivetsF 1470 Guide for Fa
7、stener Sampling for Specified Mechani-cal Properties and Performance InspectionF 1789 Terminology for F16 Mechanical Fasteners3. Terminology3.1 Terms used in this specification are defined in Termi-nology F 1789 unless otherwise defined in this specification.3.1.1 batch lotquantity of identical part
8、s cleaned, pickled,fluxed, and galvanized together at one time in a galvanizingbasket.3.1.2 galvanizinghot-dip zinc coating.3.1.3 high temperature galvanizinggalvanizing processcarried out in a ceramic vessel (kettle) at an approximatetemperature ranging between 990 and 1040F.3.1.4 hot-dip zinc coat
9、ing of mechanical fastenersprocesswhereby fasteners are zinc coated by immersion in a bath ofmolten zinc, resulting in the formation of the iron/zinc alloycoating and a zinc coating at the surface of the fastener. Thisprocess involves the removal of excess zinc by spinning theparts in a centrifuge,
10、or brushing the threaded portion, orhandling otherwise to remove the excess zinc.3.1.5 production lotbatches of parts originating from thesame manufacturing lot, processed continuously through clean-ing, pickling, fluxing, dipping in molten zinc and spun in acentrifuge, or other means, without any s
11、ignificant change intime, temperature, and concentration of the constituents of theprocess.3.1.6 stress reliefprocess of heating parts for a definitetime at a given temperature in order to relieve stress induced bywork hardening.4. Ordering Information4.1 Orders for zinc coating of fasteners to this
12、 specificationshall include the following:4.1.1 Name of product (that is bolt, stud, nut, washers, orother);4.1.2 ASTM designation and year of issue, including fas-tener specification number;4.1.3 Hydrogen embrittlement relief, as required by thepurchaser, see 7.2.3;4.1.4 Quantity of fasteners to be
13、 hot-dip zinc coated;4.1.5 Stress relief or tempering temperature to which thefasteners were subjected, if applicable;1This specification is under the jurisdiction of ASTM Committee F16 onFastener and is the direct responsibility of Subcommittee F16.03 on Coatings onFasteners.Current edition approve
14、d Feb. 1, 2005. Published February 2005.2For 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.1Copyright ASTM Inter
15、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.6 Secondary processing such as chromating, phosphat-ing, or lubrication, if applicable;4.1.7 Average galvanizing temperature to which fastenerswill be subjected, if required by the purchaser (see 7.2.2)
16、;4.1.8 Specify baking if required (see 7.2.3); and4.1.9 Certification, if required (see 14.1).5. Materials and Manufacture5.1 Condition of the As-Received FastenersThe fastenersas received by the galvanizer shall be free from contaminantsthat are not readily removed in the cleaning process and would
17、adversely affect the galvanizing.5.2 ProcessUnless otherwise covered in this specifica-tion, all processing parameters shall be in accordance with therequirements of Specification A 153/A 153M.5.2.1 Process ControlGalvanized fasteners subjected to aprocess control plan based upon batch lot level sha
18、ll complywith the batch lot sampling plan in Table 1, and the samplingplan for production lot (prevention process) as determined in10.2.2 shall be applied.5.3 Spinning and Quenching:5.3.1 Parts shall be spun immediately following removalfrom the galvanizing bath and quenched in water. In addition,sm
19、all parts shall be air cooled as needed in order to prevent theformation of zinc oxide.5.3.2 Parts, which cannot be spun shall be brushed orhandled otherwise to remove the excess zinc.5.4 Alteration of Threaded Fasteners:5.4.1 Fasteners that have been hot-dip galvanized shall notbe further altered (
20、such as subjected to a cutting, rolling,finishing-tool operation) by the galvanizer unless specificallyauthorized in writing by the purchaser.5.4.2 Hot-dip galvanizing of externally threaded fastenersshall meet the thread fitting requirements of the specifiedproduct standard or specific allowance as
21、 determined by thecustomer.NOTE 1The scope of this specification does not cover the require-ments regarding the overtapping of galvanized nuts. These requirementsare established by the applicable product standard, such as SpecificationA 563 (or others), or in writing by the purchaser, if needed.5.5
22、Secondary Processing:5.5.1 When requested by the purchaser, treatments such aschromating or phosphating shall be applied to reduce thepossibility of wet storage staining (white corrosion) or to assistsubsequent painting.5.5.2 When specified on the purchase order, the nuts, bolts,or screws shall be l
23、ubricated to enhance assembly.6. Chemical Composition of Zinc6.1 Unless otherwise specified in the product standard, thezinc used for the coating shall conform to the requirements ofthe section on Zinc of Specification A 153/A 153M.7. Safeguards Against Alteration of Fasteners MechanicalProperties7.
24、1 Stress ReliefFasteners subjected to severe work hard-ening shall be stress-relieved by the fastener manufacturerprior to hot-dip zinc coating (galvanizing).7.2 Hot-Dip Zinc Coating:7.2.1 Effect of Temperature on Mechanical Properties:7.2.1.1 Galvanizing carried out at a temperature above800F can a
25、dversely affect the final mechanical properties ofthe fasteners. Therefore, the supplier of the fasteners submit-ting the product to the galvanizer shall be aware of thetempering temperature of the fasteners relative to the tempera-ture of the galvanizing bath and the potential effect it may haveon
26、the product. When requested by the purchaser, the averagegalvanizing temperature that the fasteners will be subjected toshall be furnished.7.2.1.2 Unless otherwise required by the product standard orby the purchaser, testing for mechanical properties is notnecessary if the galvanizing process is car
27、ried out at a lowertemperature than the stress relief or tempering temperature ofthe fasteners. If the galvanizing process is carried out at ahigher temperature than the stress relief or the temperingtemperature of the fasteners, than the purchaser shall makeprovision for mechanical testing.7.2.1.3
28、Threaded fasteners made from carbon or alloy steelheat treated to the specified hardness of 40 HRC or above, orcase hardened steel fasteners shall not be hot-dip zinc coated.7.2.2 Effect of Hydrogen on the Mechanical Properties afterGalvanizing Hydrogen has the potential of being introducedinto the
29、steel during acid pickling, prior to hot-dip galvanizing.For high strength fasteners (having a specified minimumproduct hardness of 33 HRC), there is a risk of internalhydrogen embrittlement. If required by the product standard orby the purchaser, mechanical descaling (with or without flashpickling)
30、 or baking shall be conducted to reduce the risk ofinternal hydrogen embrittlement. Baking shall be conductedafter pickling and prior to hot-dip galvanizing.7.2.3 Effect of the Galvanizing TemperatureExternallythreaded ferrous fasteners over 1.00 in. diameter with aspecified minimum hardness of HRC
31、33 and higher shall not behot-dip zinc coated at high temperature in order to avoidmicrocracks.8. Coating and Dimensional Requirements8.1 Coating ThicknessThe zinc coating thickness shallmeet the requirements of Table 2.TABLE 1 Process Control of Batch LotASampling PlanSample SizeBBatch Lot Size Ave
32、rage CoatingThicknessCAdhesion AppearanceD5to25 1 1 126 to 50 1 1 251 to 150 2 1 2151 and over 2 2 2AThe acceptance criterion in all cases is zero defects.BThe sample size is the number of specimen(s) required to be tested/inspectedto the applicable criteria.CCoating thickness frequency of measureme
33、nts: one set of specimen(s) forevery five batch lots. For test method, see 11.1.DVisual inspection for conformance.F23290528.2 DimensionThe dimensional characteristics of the fas-teners shall be in accordance with the requirements of thepurchaser, when specified in the order. The purchaser shallensu
34、re that the effect of the heat generated by the galvanizingprocess is compatible with the fastener regarding the finaldimensional characteristics of the parts. Furthermore, thegalvanizer shall not be held responsible for any unanticipateddistortion of parts. In addition, the purchaser shall providef
35、asteners having sufficient dimensional allowance to accom-modate the zinc thickness deposition, as required in 8.1.8.3 Adhesion of Zinc CoatingThe zinc coating shalladhere tenaciously to the surface of the base metal. The methodfor testing the condition of adherence is specified in 11.5.9. Workmansh
36、ip, Finish, and Appearance9.1 Appearance of Zinc Coating:9.1.1 After hot-dip galvanizing, fasteners shall meet therequirements of the section on Workmanship, Finish, andAppearance of SpecificationA 153/A 153M. Galvanized wash-ers shall not be bonded to each other (see Note 2). Parts maybe dull due t
37、o the presence of silicon in the steel. The dullappearance shall not be cause for rejection.NOTE 2Hot-dip washers tend to bond to each other. Suitable accep-tance criteria shall be agreed between the purchaser and the galvanizerbefore placing the order. Unless otherwise agreed to in the purchase ord
38、er,delivered galvanized washers shall not be bonded to each other.9.1.2 The test method shall be in accordance with 11.3.9.2 Smoothness of Zinc Coating:9.2.1 The zinc coating shall be smooth and reasonablyuniform in thickness, as defined in the section on Workman-ship, Finish, and Appearance of Spec
39、ification A 153/A 153M.Smoothness of a surface is a relative term. Minor roughnessthat does not impair the intended use of the part, or roughnessthat is related to the uncoated surface condition of the part,shall not constitute grounds for rejection of the parts.9.2.2 The test method shall be in acc
40、ordance with 11.3.10. Sampling10.1 Test specimens shall be selected at random from eachproduction lot or batch lot, when applicable.10.2 Selection of the Sampling PlanProduction LotTwosampling plans are proposed, one based on detection processand one based on prevention process as defined in Termino
41、logyF 1789. The selection of the sampling plan shall be in accor-dance with Guide F 1470.10.2.1 Production LotDetection ProcessSampling forcoating thickness and for visual appearance shall be conductedin accordance with Table 1, Sample Level A, and Table 3,Sample Size A, of Guide F 1470. Sampling fo
42、r adhesion testshall be in accordance with Table 1, Sample Level C, and Table3, Sample Size C, of Guide F 1470.10.2.2 Production LotPrevention ProcessSampling forcoating thickness and for visual appearance shall be conductedin accordance with Table 2, Sample Level B, and Table 3Sample Size B, of Gui
43、de F 1470. Sampling for adhesion testshall be in accordance with Table 2, Sample Level D, and Table3, Sample Size D, of Guide F 1470.11. Test Methods11.1 Tests shall be made to ensure that the zinc coating isbeing furnished in accordance with this specification and asspecified for the following:11.2
44、 Coating Thickness:11.2.1 Average Coating Thickness on an Individual Speci-men:11.2.1.1 To calculate the average coating thickness of onespecimen, a minimum of five readings shall be taken. In casethe geometry of the specimen does not permit five readings,five test specimens shall be used to establi
45、sh the averagereading.11.2.1.2 The determination of the coating thickness shall bemade on a portion of the fastener that does not include anythreads in accordance with Practice E 376.11.2.1.3 In case of arbitration, the thickness of coating shallbe determined by cross section and optical measurement
46、, inaccordance with Test Method B 487. Thus, the thicknessdetermined is a point value. No less than five measurementsshall be made at locations on the test specimen, which are aswidely dispersed as practical, so as to be representative of thewhole surface of the test specimen. The average of thosese
47、lected measurements is the average coating thickness.11.3 Finish and AppearanceFinish and appearance shallbe visually inspected.TABLE 2 Zinc Coating ThicknessMinimum Thickness on SurfaceDimensionAAverage Thickness of AllSpecimens Tested(Production Lot)BAverage Thickness of AllSpecimens Tested(Batch
48、Lot)CAverage Thickness ofIndividual SpecimenFasteners and nuts over38 in. in diameterWashers316 in. and14 in. in thickness0.0020 in. 0.0017 in. 0.0017 in.Fasteners and nuts38 in. and under in diameterWashers under316 in. in thickness0.0017 in. 0.0015 in. 0.0015 in.AIn the case of long pieces, such a
49、s anchor rods and similar articles over 5 ft in length, the thickness measurement shall be determined at each end and the middleof the article. In the case of a fully threaded rod, the thickness measurements shall be determined at each end of the article. In no case shall the averageofthemeasurements be below the average thickness shown in the Average Thickness on Individual Specimen column (see 11.2). The number of specimens to be tested perorder shall be as specified in Section 10. NoteBased upon mathematical calculations, 1.0 oz /ft2of zinc surface cor
