American Association State HighwayDesignation: A 153/A 153M – 01a and Transportation Officials Standard AASHTO No. M232 Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware1 This standard is issued under the fixed designation A 153/A 153M; the number immediately following the designation indicates the year of 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 (e) 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. Scope B 6 Specification for Zinc (Slab Zinc)3 1.1 This specification covers zinc coatings applied by the B 487 Test Method for Measurement of Metal and Oxide hot-dip process on iron and steel hardware. Coating Thicknesses by Microscopical Examination of a 1.2 This specification is intended to be applicable to hard- Cross Section4 ware items that are centrifuged or otherwise handled to remove B 602 Test Method for Attribute Sampling of Metallic and excess galvanizing bath metal (free zinc). Coating thickness Inorganic Coatings4 grade requirements reflect this. E 376 Practice for Measuring Coating Thickness by 1.3 This specification is applicable to orders in either Magnetic-Field or Eddy-Current (Electromagnetic) Test inch-pound units (as A 153) or in SI units (as A 153M). Methods5 Inch-pound units and SI units are not necessarily exact 3. Materials and Manufacture equivalents. Within the text of this specification and where appropriate, SI units are shown in parentheses. Each system 3.1 Steel or Iron—Ferrous articles to be hot-dip zinc coated shall be used independently of the other without combining shall conform to specifications designated by the purchaser. values in any way. In the case of orders in SI units, all testing 3.2 Zinc—The zinc used for the coating shall conform to and inspection shall be done using the metric equivalent of the Specification B 6 and shall be at least equal to the grade test or inspection method as appropriate. In the case of orders designated as “Prime Western.” in SI units, such shall be stated to the galvanizer when the order 3.3 Coating Thickness Grade—The thickness grades of the is placed. coating shall conform to the requirements prescribed in Table 1.4 This standard does not purport to address all of the 1 for the material category and thickness of material in which safety concerns, if any, associated with its use. It is the the article belongs. responsibility of the user of this standard to establish appro- 3.4 Threaded Articles—The zinc coating on threads shall priate safety and health practices and determine the applica- not be subjected to a cutting, rolling, or finishing-tool opera- bility of regulatory limitations prior to use. tion, unless specifically authorized by the purchaser. In order to meet overtapping allowances, tapping the threads of nuts or 2. Referenced Documents tapped holes after galvanizing is not prohibited. 2.1 ASTM Standards: 3.5 Bare spots that are found on parts after galvanizing shall A 90/A 90M Test Method for Weight of Coating on Zinc- be renovated by use of the methods found in Practice A 780 if Coated (Galvanized) Iron or Steel Articles2 the following criteria are met. The bare spots shall have an area A 143 Practice for Safeguarding Against Embrittlement of totalling not more than 1 % of the surface area to be coated Hot-Dip Galvanized Structural Steel Products and Proce- excluding threaded areas of the piece and the bare spots shall dure for Detecting Embrittlement2 not include any threaded areas of the piece. The thickness of A 385 Practice for Providing High-Quality Zinc Coatings the repair shall be equal to the surrounding galvanized coating (Hot-Dip)2 except for repairs made by paints containing zinc dust in which A 780 Practice for Repair of Damaged and Uncoated Areas case the thickness of the repair shall be 50 % greater than the of Hot-Dip Galvanized Coatings2 thickness of the galvanized coating required for the class of material, but shall not be greater than 4.0 mils (100 µm). Repair thickness measurements shall be made in accordance with 1 Practice A 780. The galvanizer shall make repairs unless This specification is under the jurisdiction of ASTM Committee A05 on Metallic-Coated Iron and Steel Productsand is the direct responsibility of Subcom- mittee A05.13on Structural Shapes and Hardware Specifications. 3 Current edition approved October 10, 2001. Published December 2001. Origi- Annual Book of ASTM Standards, Vol 02.04. 4 nally published as A 153 – 33 T. Last previous edition A 153/A 153M – 01. Annual Book of ASTM Standards, Vol 02.05. 2 5 Annual Book of ASTM Standards, Vol 01.06. Annual Book of ASTM Standards, Vol 03.03. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. 1 COPYRIGHT ASTM International Licensed by Information Handling Services 4 Malleable castings shall be of such composition as will of projections that would interfere with the intended use of the preclude the possibility that they become embrittled by the articles. (4.2 The zinc coating shall be smooth and reasonably uni. (4.2). and that is being submitted for acceptance as a group. all plain carbon steels including those which have been galvanized. degree of cold approximately the same time. 4.80 (550) B-2—under 3⁄16 in. B The number of specimens to be tested per order shall be as specified in Section 7. dross inclusions.76 mm) and over in thickness and over 15 in.80 (550) Class B—Rolled. Minimum Weight of Zinc Coating. 1 oz /ft2 of zinc surface corresponds to an average coating thickness of 1. that does not interfere with the intended use of the part. which manifest themselves as local excess coating thickness that would interfere with function or as edge tears or spikes that present a safety hazard because of their sharpness. coatings to stretch or compress beyond the limit of elasticity. and Appearance service temperature should thus be taken into account when selecting 4. such as anchor rods and similar articles over 5 ft (1. (381 mm) and under in length 1.) References to “coating thickness” or “coating thickness grade” throughout this standard are interchangeable with “weight” in Table 1. 5. refers to the overall dimension and not to its developed length. fuged or otherwise handled to remove excess bath metal (see 1. (Based upon mathematical calculations. B-2. (381 mm) in length 1. or other defects not consistent with good galvanizing galvanizing process.6 If the galvanized material covered by this specification shall not be grounds for rejection. the Practice A 143. and B-3.52 mm) and under in diameter. anneal. An inspection lot is defined as a collection of cold-worked. Finish.3 Embrittlement is a potential condition of steel that is inspection lot. in the same manner. pressed.25 (381) 1. NOTE 2—Based upon mathematical calculations. The galvanizer. blisters. The expected 4. (381 mm) in length 2.25 (381) B-3—any thickness and 15 in. Washers under 3⁄16 in. Sampling the terms of 5.76 mm) in thickness A In the case of long pieces. directed by the purchaser to deliver items unrepaired for NOTE 3—Low service temperatures increase the risk of brittle failure of subsequent renovation by the purchaser.00 (305) 0. and galvanizing process. Steel 2. stated in Classes B-1. (4. Otherwise. Drainage bending or fabricating shall not be cause for rejection. or roughness that is related to the as-received (ungalvanized) surface condition of the part.00 (610) 1.76 and 6. seven times the coating thickness in micrometres is approximately equal to the coating in g/m2. and the fabricator shall take precautions against embrittlement.5 The zinc coating shall adhere tenaciously to the surface NOTE 1—Smoothness of surface is a relative term. 4. problems.10 (336) Class C—Fasteners over 3⁄8 in. A 153/A 153M TABLE 1 Weight of Zinc Coating for Various Classes of Material NOTE 1— Length of the piece. and other types 4. are grounds for rejection under 5. Minor roughness of the basis metal (see Section 8). (9.76 mm) in thickness and over 15 in. aging characteristics).141 µm.00 (305) and 1⁄4in.1 The zinc-coated articles shall be free from uncoated steels for galvanizing.30 (397) 1. the weight of coating shall be determined at each end and the middle of the article. and in the work.52 m) in length. the designer same pot. 5.50 (458) 1.1 Test specimens shall be selected at random from each 4. in accordance with the above calculation. form in thickness. oz/ft2(g/m2) of SurfaceA Class of Material Average of Specimens TestedB Any Individual Specimen Class A—Castings—Malleable Iron. In no case shall individual measurements be below the minimum shown in the “Any Individual Specimen’’ column.2 The method of selection and sample size shall be agreed The precautions to fabricate properly and prepare the material for galvanizing to prevent embrittlement are described in upon between the galvanizer and the purchaser.1. and forged articles (except those which would be included under Classes C and D): B-1—3⁄16 in.35 mm) in thickness Class D—Fasteners 3⁄8 in. flux deposits. 1. (4.85 (259) articles. or subsequently heat-treated so as to immunize them 4. nails and similar 1. (9. Workmanship.00 (610) 1. Washers 3⁄16in. thickness. This temperature embrittling effect varies with type of steel. against embrittlement. sample size selected from each lot shall be as follows: 2 COPYRIGHT ASTM International Licensed by Information Handling Services . areas.7 mil. any cracking or flaking of the coating resulting from the irregular coating distribution is not normally encountered. rivets. 1 g/m2 of zinc surface corresponds to an average coating thickness of 0.52 mm) in diameter and similar articles. depending on such factors as the steel type galvanized articles of the same kind that has been galvanized at (strength level. or they shall be either cooled from the practice. is bent or otherwise fabricated to the degree that causes the zinc NOTE 2—Since this specification is applicable to items that are centri. unless the method described in 6.4 Adherence in 4. They shall then screws.2. and shall be so 6.1 In the case of fasteners such as bolts. which are as widely dispersed as practical.3 is used.3.1 and 4. regalva- 6. the determination of the thickness of coating shall be conform to the requirements of this specification. 10 001 and over 20 7. is being performed. Keywords of a stout knife.2. 8. tending to remove a portion of the coating.2.2 In the case of materials inspected after galvanizing.2 Thickness of Coating: 8. the galvanizer is not prohibited from sorting the 6. 6. conducted as not to interfere unnecessarily with the operation 6. The thickness thus determined is a by the purchaser in satisfactory condition.3 and 4.3 If a set of test specimens fails to conform to the 6.2. use of a magnetic thickness gage in conformity with Practice 8. galvanized coatings.1.2. steel products.2 is used.2. Inspection 5. Certification test article. every respect.2. and nized. NOTE 4—This method does not take into account the weight of iron 8. Rejection and Retest 6. the is the specimen coating thickness. with the use to be point value. metallic coated. zinc.1. The average of no less than five such measurements 10. 6. prior to shipments. by this specification and the requirements have been met.3 Embrittlement in 4. steel hardware.1 The average weight of the zinc coating shall be 8. No less than five such measurements shall be made made of the article being taken into consideration. a report of galvanizer and the purchaser.1 When specified in the purchase order or contract. Test Methods which concern the application of the zinc coating to the material ordered. two additional sets shall be the weight of coating shall be determined by stripping one or tested. All specified for the following: inspection and tests shall be made at the place of manufacture 6. senting each lot have been either tested or inspected as directed brittlement shall be tested in accordance with Practice A 143. 6. steel be considered inadequate if the coating flakes off in the form of products 3 COPYRIGHT ASTM International Licensed by Information Handling Services . Base metal galvanizer and the purchaser. purchaser shall be furnished certification that samples repre- 6. applied with considerable pressure in a manner 11. zinc coatings. reactivity will affect the extent of underestimation. lot and submitting it once again for inspection.2 or 6. embrittlement are not prohibited from being stripped.1 The inspector representing the purchaser shall have specification shall not be used to determine the conformance to access at all times while work on the contract of the purchaser other requirements. Packaging 6. unless the method described zinc-coated articles as shall be required to ensure their receipt in 6.1 or 6. of the works.4.3 A specimen that fails to conform to a requirement of this 7. The manufacturer shall afford the inspector 6.2. made on a portion of the article that does not include any threads.4 Materials that have been rejected for reasons other than E 376. The adherence shall zinc coated. It will thus to fail to conformance tests shall be agreed upon between the underestimate coating weight by up to approximately 10 %. 9.2 Finish and appearance in 4. the test results shall be furnished.2. so as to be representative of the whole surface of the 10.3 The thickness of coating shall be determined by cross 9.1 Tests shall be made to ensure that the zinc coating is all reasonable facilities to satisfy him that the zinc coating is being furnished in accordance with this specification and as being furnished in accordance with this specification. The tests shall be performed through agreement between the When specified in the purchase order or contract.2.1 or 6. to those areas of the manufacturer’s work 6.2. at locations on the test article.1 The supplier shall employ such methods of packaging section and optical measurement. requirements of this specification.3 Embrittlement—Hardware that is susceptible to em.3 is used.4 Adherence—Determine adherence of the zinc coating to the surface of the base metal by cutting or prying with the point 11.1 Thickness of coating in 3.1.5.2 The number of specimens in a sample of a lot permitted reacted from the article that is incorporated into the coating.1 When partial inspection of materials to determine con- determined by weighing specimens after pickling and drying formity with visual requirements of Section 4 warrants rejec- and again after galvanizing unless the method described in tion of a lot. or the lot of material represented by the or the average thickness of coating shall be determined with the specimens shall be rejected.2. Do not use testing carried out at edges or corners 4 to 500 3 501 to 1200 5 (points of lowest coating adherence) to determine adherence of 1201 to 3200 8 coating. A 153/A 153M Number of Pieces in Lot Sample Size a layer of skin so as to expose the base metal in advance of the 3 or less all knife point. do not use removal of small particles of the 3201 to 10 000 13 coating by paring or whittling to determine failure. and resubmitted for test and inspection. Likewise. unless otherwise specified.1 coatings. both of which shall conform to the requirements in more specimens in accordance with Test Method A 90/A 90M.1. nuts. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Users of this standard are expressly advised that determination of the validity of any such patent rights. 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