1、Designation: A153/A153M 16A153/A153M 16a American Association State Highwayand Transportation Officials StandardAASHTO No. M232Standard Specification forZinc Coating (Hot-Dip) on Iron and Steel Hardware1This standard is issued under the fixed designation A153/A153M; the number immediately following
2、the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved fo
3、r use by agencies of the U.S. Department of Defense.1. Scope*1.1 This specification covers zinc coatings applied by the hot-dip process on iron and steel hardware. The hot-dip galvanizingprocess consists of parts being immersed in molten zinc for a sufficient time to allow a metallurgical reaction b
4、etween iron fromthe steel surface and the molten zinc, resulting in the formation of Zn/Fe alloy layers bonding the coating to the steel surface.1.2 This specification is intended to be applicable to hardware items that are centrifuged or otherwise handled to remove excessgalvanizing bath metal (fre
5、e zinc). Coating thickness grade requirements reflect this.1.3 Fasteners that must comply with the Fastener Quality Act require specific statistical sampling during the inspection of thefastener lots. Requirements for the sampling of these fasteners can be found in F2329/F2329M.1.4 This specificatio
6、n is applicable to orders in either inch-pound units (as A153) or in SI units (as A153M). Inch-pound unitsand SI units are not necessarily exact equivalents. Within the text of this specification and where appropriate, SI units are shownin brackets. Each system shall be used independently of the oth
7、er without combining values in any way. In the case of orders inSI units, all testing and inspection shall be done using the metric equivalent of the test or inspection method as appropriate. In thecase of orders in SI units, such shall be stated to the galvanizer when the order is placed.1.5 This s
8、tandard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1
9、ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy CoatingsA143/A143M Practice for Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel Products and Procedurefor Detecting EmbrittlementA780 Practice for Repair of Da
10、maged and Uncoated Areas of Hot-Dip Galvanized CoatingsA902 Terminology Relating to Metallic Coated Steel ProductsB6 Specification for ZincB487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross SectionB960 Specification for Prime Western Grade-Rec
11、ycled (PWG-R) ZincE376 Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing MethodsF1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance InspectionF1789 Terminology for F16 Mechanical FastenersF2329/F2329M Specificati
12、on for Zinc Coating, Hot-Dip, Requirements forApplication to Carbon andAlloy Steel Bolts, Screws,Washers, Nuts, and Special Threaded Fasteners3. Terminology3.1 Definitions:1 This specification is under the jurisdiction ofASTM Committee A05 on Metallic-Coated Iron and Steel Products and is the direct
13、 responsibility of Subcommittee A05.13on Structural Shapes and Hardware Specifications.Current edition approved Feb. 1, 2016. Published February 2016November 2016. Originally approved in 1933. Last previous edition approved in 20092016 asA153/A153M - 09.A153/A153M - 16. DOI: 10.1520/A0153_A0153M-16.
14、10.1520/A0153_A0153M-16A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standar
15、d and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases o
16、nly the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 The following
17、 terms and definitions are specific to this specification. Terminology A902 contains other terms anddefinitions relating to metallic-coated steel products. Terminology F1789 contains other terms and definitions relating tomechanical fasteners.3.2 Definitions of Terms Specific to This Standard:3.2.1
18、average coating thickness, nthe average of the specimen coating thickness values for the samples in an inspection lot.3.2.2 bare spots, nuncoated areas on the surface of the steel part that contain no measurable zinc coating.3.2.3 dross inclusions, nthe iron/zinc intermetallics present in a galvaniz
19、ed coating in a form other than the layer growth ofthe coating.3.2.4 individual measurement, nthe reading from a magnetic thickness gauge of a single coating spot thickness, or themicroscopic reading of a coating thickness as seen in an optical microscope at one spot.3.2.5 inspection lot, nthe quant
20、ity of identical parts cleaned, fluxed and galvanized together at one time in an appropriatecontainer that is being submitted for acceptance as a group.3.2.6 malleable casting, na steel article that has been subjected to a prolonged anneal to decarburize or graphitize the part toremove as much of th
21、e carbon as possible or to convert the carbon to graphite, which permits plastic deformation in compressionwithout rupture.3.2.7 sample, na collection of individual units of product from a single inspection lot selected in accordance with Section 6and intended to represent that inspection lot for ac
22、ceptance.3.2.8 specimen, nan individual test article upon which thickness measurements or weight determinations are performed.3.2.9 specimen coating thickness, nthe average thickness from no less than five test measurements on a specimen, when eachmeasurement location is selected to provide the wide
23、st dispersion (in all applicable directions) of locations within the specimenvolume.3.2.10 threaded areas, nthe sections of a steel part that have threads formed before hot-dip galvanizing.4. Materials and Manufacture4.1 Steel or IronFerrous articles to be hot-dip zinc coated shall conform to specif
24、ications designated by the purchaser.4.2 ZincThe zinc used for the coating shall conform to Specification B6, or Specification B960, or both, and shall be at leastequal to the grade designated as “Prime Western.”4.2.1 If a zinc alloy is used as the primary feed for the galvanizing bath, then the bas
25、e material used to make that alloy shallconform to Specification B6 or Specification B960, or both.4.2.2 The molten metal in the working volume of the galvanizing bath shall contain not less than an average value of 98.0 %zinc by weight mass.NOTE 1The galvanizer may choose to add trace amounts of ce
26、rtain elements (for example, aluminum, nickel, bismuth, or tin) to the zinc bath to helpin the processing of certain reactive steels or to enhance the cosmetic appearance of the finished product. The elements can be added to the galvanizingbath as a master feed alloy, or they can be added to the bat
27、h by the galvanizer as individual feeds.4.3 Minimum Coating Weight Mass or Minimum Coating ThicknessThe minimum coating weight mass or the minimumcoating thickness shall conform to the requirements prescribed in Table 1 for the material category and thickness of material inwhich the article belongs.
28、4.4 Threaded ArticlesThe zinc coating on threads shall not be subjected to a cutting, rolling, or finishing-tool operation, unlessspecifically authorized by the purchaser. In order to meet overtapping allowances, tapping the threads of nuts or tapped holes aftergalvanizing is not prohibited.4.5 Touc
29、h-up and RepairBare spots that are found on parts after galvanizing shall be renovated by use of the methods foundin Practice A780 if the following criteria are met. The bare spots shall have an area totalling not more than 1 % of the surface areato be coated excluding threaded areas of the piece an
30、d the bare spots shall not include any threaded areas of the piece.The thicknessof the repair shall be equal to the surrounding galvanized coating except for repairs made by paints containing zinc dust in whichcase the thickness of the repair shall be 50 % greater than the thickness of the galvanize
31、d coating required for the class of material,but shall not be greater than 4.0 mils 100 m. Repair thickness measurements shall be made in accordance with Practice A780.The galvanizer shall make repairs unless directed by the purchaser to deliver items unrepaired for subsequent renovation by thepurch
32、aser.5. Workmanship, Finish, and Appearance5.1 The zinc-coated articles shall be free from uncoated areas, blisters, flux deposits, dross inclusions, and other types ofprojections that would interfere with the intended use of the articles, or other defects not consistent with good galvanizing practi
33、ce.5.2 The zinc coating shall be reasonably smooth and uniform in thickness.NOTE 2Smoothness of surface is a relative term. Minor roughness that does not interfere with the intended use of the part, or roughness that is relatedA153/A153M 16a2to the as-received (ungalvanized) surface condition of the
34、 part, shall not be grounds for rejection.NOTE 3Since this specification is applicable to items that are centrifuged or otherwise handled to remove excess bath metal (see 1.2), irregular coatingdistribution is not normally encountered. Drainage problems, which manifest themselves as local excess coa
35、ting thickness that would interfere withfunction or as edge tears or spikes that present a safety hazard because of their sharpness, are grounds for rejection under the terms of 5.1.5.3 Embrittlement is a potential condition of steel that is cold-worked, depending on such factors as the steel type (
36、strengthlevel, aging characteristics), thickness, degree of cold work, and galvanizing process. The galvanizer, the designer and thefabricator shall take precautions against embrittlement. The precautions to fabricate properly and prepare the material forgalvanizing to prevent embrittlement are desc
37、ribed in Practice A143/A143M.NOTE 4Low service temperatures increase the risk of brittle failure of all plain carbon steels including those which have been galvanized. Thistemperature embrittling effect varies with type of steel. The expected service temperature should thus be taken into account whe
38、n selecting steels forgalvanizing.5.4 Malleable castings shall be of such composition as will preclude the possibility that they become embrittled by thegalvanizing process, or they shall be either cooled from the anneal, or subsequently heat-treated so as to immunize them againstembrittlement.5.5 T
39、he zinc coating shall adhere tenaciously to the surface of the base metal.5.6 If the galvanized material covered by this specification is bent or otherwise fabricated to the degree that causes the zinccoatings to stretch or compress beyond the limit of elasticity, any cracking or flaking of the coat
40、ing resulting from the bending orfabricating shall not be cause for rejection.5.7 High strength bolts, typically over 150,000 lb/in.2 ultimate tensile strength, may be subject to hydrogen embrittlement.Practices to safeguard against hydrogen embrittlement are described in Specification A143/A143M.6.
41、 Sampling6.1 Test specimens shall be selected at random from each inspection lot.6.2 The method of selection and sample size shall be agreed upon between the galvanizer and the purchaser. Otherwise, thesample size selected from each lot shall be as follows:Number of Pieces in Lot Sample Size3 or les
42、s all4 to 500 3501 to 1200 51201 to 3200 83201 to 10 000 1310 001 and over 206.3 A specimen that fails to conform to a requirement of this specification shall not be used to determine the conformance toother requirements.6.4 The method of sampling for fasteners that are required to meet the standard
43、s of the Fastener Quality Act is described inGuide F1470. Sample quantities and definitions of terminology are included in the referenced specification.TABLE 1 Thickness or Weight Mass of Zinc Coating for Various Classes of MaterialNOTE 1 Length of the piece, stated in Classes B-1, B-2, and B-3, ref
44、ers to the finished dimension of the piece after fabrication.Class of MaterialWeight Mass of Zinc Coating,oz/ft 2 g/m2 of Surface, MinimumCoating Thickness, milsmicrons, MinimumAverage ofSpecimensTestedAnyIndividualSpecimenAverage ofSpecimensTestedAnyIndividualSpecimenClass ACastingsMalleable Iron,
45、Steel 2.00 610 1.80 550 3.4 86 3.1 79Class BRolled, pressed, and forged articles(except those which would be included under Classes C and D):B-158 in. 15.88 mm and over in thicknessand over 15 in. 381 mm in length2.00 610 1.80 550 3.4 86 3.1 79B-2under 58 in. 15.88 mm in thickness andover 15 in. 381
46、 mm in length1.50 458 1.25 381 2.6 66 2.1 53B-3any thickness and 15 in. 381 mm and under in length 1.30 397 1.10 336 2.2 56 1.9 48Class CFasteners over 38 in. 9.52 mm in diameterand similar articles. Washers 316 in. and greater 4.76 mm andgreater in thickness1.25 381 1.00 305 2.1 53 1.7 43Class DFas
47、teners 38 in. 9.52 mm and under in diameter,rivets, nails and similar articles. Washers under 316 in. 4.76mm in thickness1.00 305 0.85 259 1.7 43 1.4 36A153/A153M 16a37. Test Methods7.1 Tests shall be made to ensure that the zinc coating is being furnished in accordance with this specification and a
48、s specifiedfor the following:7.1.1 Minimum coating weight mass or minimum coating thickness in 4.3.7.1.2 Finish and appearance in 5.1 and 5.2.7.1.3 Embrittlement in 5.3 and 5.4.7.1.4 Adherence in 5.5.7.2 Average Weight Mass of Coating:7.2.1 The average weight mass of the zinc coating shall be determ
49、ined by weighing specimens after pickling and drying andagain after galvanizing unless the method described in 7.2.2 is used. The number of specimens that are used to determine theaverage of an inspection lot shall be derived from Section 6.NOTE 5This method does not take into account the weight mass of iron reacted from the article that is incorporated into the coating. It will thusunderestimate coating weight mass by up to approximately 10 %. Base me
