Designation:F2329–05
Standard Specification for
Zinc Coating,Hot-Dip,Requirements for Application to Carbon and Alloy Steel Bolts,Screws,Washers,Nuts,and Special Threaded Fasteners1
This standard is issued under thefixed designation F2329;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope
1.1This specification covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws,washers,nuts,and special threaded fasteners applied by the hot-dip coating process.Nails and rivets are not included in this specification.
1.2It is intended to be applicable to fasteners that are centrifuged or otherwi handled to remove excess galvanizing bath metal(free zinc).
1.3This standard does not purport to address all of the safety concerns,if any,associated with its u.It is the responsibility of the ur of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to u.
2.Referenced Documents
2.1ASTM Standards:2
A153/A153M Specification for Zinc Coating(Hot-Dip)on Iron and Steel Hardware
A563Specification for Carbon and Alloy Steel Nuts
B487Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of a Cross Section.
E376Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current(Electromagnetic)Exami-nation Methods
F606Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners, Washers,and Rivets
F1470Guide for Fastener Sampling for Specified Mechani-cal Properties and Performance Inspection
F1789Terminology for F16Mechanical Fasteners 3.Terminology
3.1Terms ud in this specification are defined in Termi-nology F1789unless otherwi defined in this specification.
3.1.1batch lot—quantity of identical parts cleaned,pickled,fluxed,and galvanized together at one time in a galvanizing basket.
3.1.2galvanizing—hot-dip zinc coating.
3.1.3high temperature galvanizing—galvanizing process carried out in a ceramic vesl(kettle)at an approximate temperature ranging between990and1040°F.
3.1.4hot-dip zinc coating of mechanical fasteners—process whereby fasteners are zinc coated by immersion in a bath of molten zinc,resulting in the formation of the iron/zinc alloy coating and a zinc coating at the surface of the fastener.This process involves the removal of excess zinc by spinning the parts in a centrifuge,or brushing the threaded portion,or handling otherwi to remove the excess zinc.
3.1.5production lot—batches of parts originating from the same manufacturing lot,procesd continuously through clean-ing,pickling,fluxing,dipping in molten zinc and spun in a centrifuge,or other means,without any significant change in time,temperature,and concentration of the constituents of the process.
3.1.6stress relief—process of heating parts for a definite time at a given temperature in order to relieve stress induced by work hardening.
4.Ordering Information
4.1Orders for zinc coating of fasteners to this specification shall include the following:
4.1.1Name of product(that is bolt,stud,nut,washers,or other);
4.1.2ASTM designation and year of issue,including fas-tener specification number;
4.1.3Hydrogen embrittlement relief,as required by the purchar,e7.2.3;
4.1.4Quantity of fasteners to be hot-dip zinc coated;
4.1.5Stress relief or tempering temperature to which the fasteners were subjected,if applicable;
1This specification is under the jurisdiction of ASTM Committee F16on
Fastener and is the direct responsibility of Subcommittee F16.03on Coatings on
Fasteners.
Current edition approved Feb.1,2005.Published February2005.
2For referenced ASTM standards,visit the ASTM website,www.astm,or
contact ASTM Customer Service at rvice@astm.For Annual Book of ASTM
Standards volume information,refer to the standard’s Document Summary page on
the ASTM website.
Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
4.1.6Secondary processing such as chromating,phosphat-ing,or lubrication,if applicable;
4.1.7Average galvanizing temperature to which fasteners will be subjected,if required by the purchar (e 7.2.2);4.1.8Specify baking if required (e 7.2.3);and 4.1.9Certification,if required (e 14.1).
5.Materials and Manufacture
5.1Condition of the As-Received Fasteners —The fasteners as received by the galvanizer shall be free from contaminants that are not readily removed in the cleaning process and would adverly affect the galvanizing.
5.2Process —Unless otherwi covered in this specifica-tion,all processing parameters shall be in accordance with the requirements of Specification A 153/A 153M .
5.2.1Process Control —Galvanized fasteners subjected to a process control plan bad upon batch lot level shall comply with the batch lot sampling plan in Table 1,and the sampling plan for production lot (prevention process)as determined in 10.2.2shall be applied.
5.3Spinning and Quenching :
5.3.1Parts shall be spun immediately following removal from the galvanizing bath and quenched in water.In addition,small parts shall be air cooled as needed in order to prevent the formation of zinc oxide.
5.3.2Parts,which cannot be spun shall be brushed or handled otherwi to remove the excess zinc.5.4Alteration of Threaded Fasteners :
5.4.1Fasteners that have been hot-dip galvanized shall not be further altered (such as subjected to a cutting,rolling,finishing-tool operation)by the galvanizer unless specifically authorized in writing by the purchar.
5.4.2Hot-dip galvanizing of externally threaded fasteners shall meet the thread fitting requirements of the specified product standard or specific allowance as determined by the customer.
N OTE 1—The scope of this specification does not cover the require-ments regarding the overtapping of galvanized nuts.The requirements are established by the applicable product standard,such as Specification A 563(or others),or in writing by the purchar,if needed.
5.5Secondary Processing :
5.5.1When requested by the purchar,treatments such as chromating or phosphating shall be applied to reduce the possibility of wet storage staining (white corrosion)or to assist subquent painting.
5.5.2When specified on the purcha order,the nuts,bolts,or screws shall be lubricated to enhance asmbly.
6.Chemical Composition of Zinc
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6.1Unless otherwi specified in the product standard,the zinc ud for the coating shall conform to the requirements of the ction on Zinc of Specification A 153/A 153M .
7.Safeguards Against Alteration of Fasteners Mechanical Properties
7.1Stress Relief —Fasteners subjected to vere work hard-ening shall be stress-relieved by the fastener manufacturer prior to hot-dip zinc coating (galvanizing).7.2Hot-Dip Zinc Coating :
7.2.1Effect of Temperature on Mechanical Properties :7.2.1.1Galvanizing carried out at a temperature above 800°F can adverly affect the final mechanical properties of the fasteners.Therefore,the supplier of the fasteners submit-ting the product to the galvanizer shall be aware of the tempering temperature of the fasteners relative to the tempera-ture of the galvanizing bath and the potential effect it may have on the product.When requested by the purchar,the average galvanizing temperature that the fasteners will be subjected to shall be furnished.
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7.2.1.2Unless otherwi required by the product standard or by the purchar,testing for mechanical properties is not necessary if the galvanizing process is carried out at a lower temperature than the stress relief or tempering temperature of the fasteners.If the galvanizing process is carried out at a higher temperature than the stress relief or the tempering temperature of the fasteners,than the purchar shall make provision for mechanical testing.
7.2.1.3Threaded fasteners made from carbon or alloy steel heat treated to the specified hardness of
40HRC or above,or ca hardened steel fasteners shall not be hot-dip zinc coated.7.2.2Effect of Hydrogen on the Mechanical Properties after Galvanizing —Hydrogen has the potential of being introduced into the steel during acid pickling,prior to hot-dip galvanizing.For high strength fasteners (having a specified minimum product hardness of 33HRC),there is a risk of internal hydrogen embrittlement.If required by the product standard or by the purchar,mechanical descaling (with or without flash pickling)or baking shall be conducted to reduce the risk of internal hydrogen embrittlement.Baking shall be conducted after pickling and prior to hot-dip galvanizing.
7.2.3Effect of the Galvanizing Temperature —Externally threaded ferrous fasteners over 1.00in.diameter with a specified minimum hardness of HRC 33and higher shall not be hot-dip zinc coated at high temperature in order to avoid microcracks.
8.Coating and Dimensional Requirements
8.1Coating Thickness —The zinc coating thickness shall meet the requirements of Table 2.
TABLE 1Process Control of Batch Lot A
Sampling Plan
Sample Size B
对联句子Batch Lot Size Average Coating Thickness C
Adhesion
Appearance D
5to 2511126to 5011251to 150212151and over
2
2
2
A The acceptance criterion in all cas is zero defects.
B
The sample size is the number of specimen(s)required to be tested/inspected to the applicable criteria.C
Coating thickness frequency of measurements:one t of specimen(s)for every five batch lots.For test method,e 11.1.D
Visual inspection for
conformance.
8.2Dimension —The dimensional characteristics of the fas-teners shall be in accordance with the requirements of the purchar,when specified in the order.The purchar shall ensure that the effect of the heat generated by the galvanizing process is compatible with the fastener regarding the final dimensional characteristics of the parts.Furthermore,the galvanizer shall not be held responsible for any unanticipated distortion of parts.In addition,the purchar shall provide fasteners having sufficient dimensional allowance to accom-modate the zinc thickness deposition,as required in 8.1.
8.3Adhesion of Zinc Coating —The zinc coating shall adhere tenaciously to the surface of the ba metal.The method for testing the condition of adherence is specified in 11.5.9.Workmanship,Finish,and Appearance 9.1Appearance of Zinc Coating :
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9.1.1After hot-dip galvanizing,fasteners shall meet the requirements of the ction on Workmanship,
Finish,and Appearance of Specification A 153/A 153M .Galvanized wash-ers shall not be bonded to each other (e Note 2).Parts may be dull due to the prence of silicon in the steel.The dull appearance shall not be cau for rejection.
N OTE 2—Hot-dip washers tend to bond to each other.Suitable accep-tance criteria shall be agreed between the purchar and the galvanizer before placing the order.Unless otherwi agreed to in the purcha order,delivered galvanized washers shall not be bonded to each other.
9.1.2The test method shall be in accordance with 11.3.9.2Smoothness of Zinc Coating :
9.2.1The zinc coating shall be smooth and reasonably uniform in thickness,as defined in the ction on Workman-ship,Finish,and Appearance of Specification A 153/A 153M .Smoothness of a surface is a relative term.Minor roughness that does not impair the intended u of the part,or roughness that is related to the uncoated surface condition of the part,shall not constitute grounds for rejection of the parts.
9.2.2The test method shall be in accordance with 11.3.10.Sampling
10.1Test specimens shall be lected at random from each production lot or batch lot,when applicable.
10.2Selection of the Sampling Plan–Production Lot —Two sampling plans are propod,one bad on detection process
and one bad on prevention process as defined in Terminology F 1789.The lection of the sampling plan shall be in accor-dance with Guide F 1470.
10.2.1Production Lot–Detection Process —Sampling for coating thickness and for visual appearance shall be conducted in accordance with Table 1,Sample Level A,and Table 3,Sample Size A,of Guide F 1470.Sampling for adhesion test shall be in accordance with Table 1,Sample Level C,and Table 3,Sample Size C,of Guide F 1470.
10.2.2Production Lot–Prevention Process —Sampling for coating thickness and for visual appearance shall be conducted in accordance with Table 2,Sample Level B,and Table 3Sample Size B,of Guide F 1470.Sampling for adhesion test shall be in accordance with Table 2,Sample Level D,and Table 3,Sample Size D,of Guide F 1470.11.Test Methods
11.1Tests shall be made to ensure that the zinc coating is being furnished in accordance with this specification and as specified for the following:11.2Coating Thickness :
11.2.1Average Coating Thickness on an Individual Speci-men :
周岁蛋糕11.2.1.1To calculate the average coating thickness of one specimen,a minimum of five readings shall be taken.In ca the geometry of the specimen does not permit five readings,five test specimens shall be ud to establish the average reading.
11.2.1.2The determination of the coating thickness shall be made on a portion of the fastener that does not include any threads in accordance with Practice E 376.
11.2.1.3In ca of arbitration,the thickness of coating shall be determined by cross ction and optical measurement,in accordance with Test Method B 487.Thus,the thickness determined is a point value.No less than five measurements shall be made at locations on the test specimen,which are as widely disperd as practical,so as to be reprentative of the whole surface of the test specimen.The average of tho lected measurements is the average coating thickness.
11.3Finish and Appearance —Finish and appearance shall be visually inspected.
TABLE 2Zinc Coating Thickness
Minimum Thickness on Surface
Dimension A
Average Thickness of All Specimens Tested (Production Lot)B
Average Thickness of All
Specimens Tested (Batch Lot)C
Average Thickness of Individual Specimen
Fasteners and nuts over 3⁄8in.in diameter Washers 3⁄16in.and 1⁄4in.in thickness
0.0020in.0.0017in.0.0017in.Fasteners and nuts 3⁄8in.and under in diameter Washers under 3⁄16in.in thickness
0.0017in.
0.0015in.
0.0015in.
A
大学宿舍排名In the ca of long pieces,such as anchor rods and similar articles over 5ft in length,the thickness measurement shall be determined at each end and the middle of the article.In the ca of a fully threaded rod,the thickness measurements shall be determined at each end of the article.In no ca shall the average of the measurements be below the average thickness shown in the Average Thickness on Individual Specimen column (e 11.2).The number of specimens to be tested per order shall be as specified in Section 10.Note—Bad upon mathematical calculations,1.0oz /ft 2of zinc surface corresponds to an average coating thickness of 0.0017in.B
For test method,e 11.2.In no ca shall the average reading of a single specimen be below the average thickness shown in the Average Thickness on Individual Specimen column.C
See 5.2.1and Table 1.For test method,e 11.2.In no ca shall the average reading of a single specimen be below the average thickness shown in the Average Thickness on Individual Specimen
column.
11.4Embrittlement Test—If the product standard requires testing for hydrogen embrittlement of galvanized fasteners, testing shall be done in accordance with Test Methods F606or other test method(s),as required by the purchar.
11.5Adhesion Test—Testing for adherence shall be con-ducted as determined in the ction on Adherence of Specifi-cation A153/A153M.
12.Inspection
12.1When dimensional inspection of the fasteners by the galvanizer is required by the purchar in the order,the purchar shall provide the necessary inspection tools and gages to the galvanizer.
12.2The reprentative of the purchar shall have access at all times while work on the contract of the purchar is being performed,to tho areas of the galvanizer’s work which concern the application of the zinc coating to the fastener ordered.The manufacturer shall afford the reprentative of the purchar all reasonable facilities to satisfy him that the zinc coating is being furnished in accordance with this specification. All inspections and tests shall be made at the place of manufacture prior to shipments,unless otherwi specified,and shall be conducted so as not to unnecessarily interfere with the operation of the works.
13.Rejection and Rehearing
13.1When partial inspection of fasteners to determine conformity with visual requirements of Section9warrants rejection of a lot,the galvanizer may sort the lot and submit it once again for inspection.
13.2Disposition of nonconforming lots shall be in accor-dance with the ction on Disposition of Nonconforming Lots of Guide F1470.
13.3Fasteners that have been rejected for reasons other than embrittlement may be stripped and re-galvanized and submit-ted for test and inspection.They shall then conform to the requirements of this specification.
14.Certification
14.1When specified in the purcha order or contract, certification shall be furnished declaring that samples repre-nting each lot have been either tested or inspected,as required by this specification,and that the requirements have been met.When specified in the purcha order or contract,the average galvanizing temperature shall be reported and the average thickness of the production lot shall be furnished. 15.Packaging and Package Marking
15.1When the galvanizer is required to pack hot-dip gal-vanized fasteners,they should not be packed in unventilated containers,if fabricated from unasoned wood.The packaging shall comply with the purchar requirements.
16.Keywords
16.1coatings,zinc;galvanized coatings;steel zinc coated; steel fastener products,metallic coated;zinc coating fastener products
APPENDIXES呼延守用
(Nonmandatory Information)
X1.GALV ANIZING TEMPERATURE
X1.1Normally galvanizing is carried out at a bath tem-perature of820to900°F.High temperature galvanizing is ud to produce a smoother and thinner coating and is carried out at a bath temperature of990to1040°F.Thefinish obtained using the high temperature process is dull.
X2.V ARIATION IN COATING
X2.1During galvanizing of a production lot,variation can be experienced due to factors inherent to the galvanizing process,such as immersion time,zinc temperature,time span between removal of fasteners from the zinc bath and the centrifuging,and the
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like.
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