1、Designation: A 1059/A 1059M 08Standard Specification forZinc Alloy Thermo-Diffusion Coatings (TDC) on SteelFasteners, Hardware, and Other Products1This standard is issued under the fixed designation A 1059/A 1059M; the number immediately following the designation indicates theyear of original adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the general requirements forprotective zinc coat
3、ings (hereinafter referred to as the coatings)to be applied by the thermo-diffusion coating (TDC) method,to various products made of carbon steel, including low andhigh tensile parts as well as of wrought iron, sintered ironsteel-powder and various steel and stainless alloys. TDC iscarried out by im
4、mersing the parts in a zinc alloy powder atelevated temperature for a period of time, causing a metallur-gical diffusion process of zinc and iron. Further processingmay be added, such as, passivation, topcoat application, paintapplication, etc.1.2 This specification is applicable to orders in either
5、inch-pound units (as A 1059) or in SI units (as A 1059M).Inch-pound units and SI units are not necessarily exactequivalents. Within the text of this specification and whereappropriate, SI units are shown in brackets. Each system shallbe used independently of the other without combining values inany
6、way. In the case of orders in SI units, all testing andinspection shall be done using the metric equivalent of the testor inspection method as appropriate. In the case of orders ininch-pound units, such shall be stated to the applicator whenthe order is placed.1.3 This standard does not purport to a
7、ddress 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.2. Referenced Documents2.1 ASTM Standards:2A 90/A 90M
8、Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA 385 Practice for Providing High-Quality Zinc Coatings(Hot-Dip)A 700 Practices for Packaging, Marking, and LoadingMethods for Steel Products for ShipmentA 902 Terminology Relating to Metallic Coated Ste
9、el Prod-uctsB 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of CrossSectionD 521 Test Methods for Chemical Analysis of Zinc Dust(Metallic Zinc Powder)D 6386 Practice for Preparation of Zinc (Hot-Dip Galva-nized) Coated Iron and Steel Product and Har
10、dwareSurfaces for PaintingE 376 Practice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) Exami-nation MethodsF 1789 Terminology for F16 Mechanical FastenersF 2329 Specification for Zinc Coating, Hot-Dip, Require-ments for Application to Carbon and Alloy Steel Bolts
11、,Screws, Washers, Nuts, and Special Threaded FastenersF 2674 Specification for Zinc Coating, Hot-Dip, Require-ments for Application to Carbon and Alloy Steel Bolts,Screws, Washers, Nuts, and Special Threaded FastenersMetric3. Terminology3.1 The following terms and definitions are specific to thisspe
12、cification. Terminology A 902 contains other terms anddefinitions relating to metallic-coated steel products. Terminol-ogy F 1789 contains other terms and definitions relating tomechanical fasteners.3.2 Definitions of Terms Specific to This Standard:3.2.1 thermo-diffusion coatinga process where the
13、steelproduct is heated in close contact with zinc powder or zincmixture.3.2.2 thermo-diffusion coatinga coating made by thermo-diffusion coating process, consisting of zinc/iron alloys.1This specification is under the jurisdiction of ASTM Committee A05 onMetallic-Coated Iron and Steel Products and i
14、s the direct responsibility ofSubcommittee A05.13 on Structural Shapes and Hardware Specifications.Current edition approved Nov. 15, 2008. Published December 2008.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
15、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 zinc powderthe coating material used to providecorrosion protection to steel.
16、3.2.4 zinc mixturea combination of zinc powder and othermetallic materials to be used as a coating material in the TDCprocess.4. Ordering Information4.1 Orders for coatings provided under this specificationshall include the following:4.1.1 Quantity (number of pieces to be coated) and totalweight.4.1
17、.2 Description (type and size of products) and weight.4.1.3 ASTM specification designation and year of issue.4.1.4 Material identification (see 5.1) and surface conditionor contamination.4.1.5 Sampling plan, if different from Section 8.4.1.6 Special test requirements, if different from Section 9(see
18、 9.1).4.1.7 Special requirements (special stacking, heavier coat-ing weight, etc.).4.1.8 Tagging or piece identification method.4.2 Additional InformationAdditional information maybe required in certain circumstances. In these cases thepurchaser will furnish the applicator with the following addi-ti
19、onal information:4.2.1 Any likely effects on the metallurgical properties ofthe base material caused by processing temperatures of up to1092F 500C.4.2.2 Determination of areas considered as significant sur-faces. This should be done by drawings or by providingsamples with suitable markings.4.2.3 Any
20、 critical thickness tolerances, such as when boltsand nuts are used. This should be done on the productsdrawing or on the purchase order.4.2.4 Any special pre-treatment requirements or the exist-ence of other materials, lubricants, stripping materials, pre-existing corrosion, etc.4.2.5 Whether quali
21、ty certificate is required or not.5. Materials and Manufacture5.1 Requirements to design of the products to be coatedwith zinc are detailed in Practice A 385. The followingprovisions are necessary to produce a high quality coating.5.1.1 The products to be coated with zinc include parts andassemblies
22、 of various sizes: presswork, forged, cast, machinedproducts (nuts, washers, bolts, nails, chains, small roundbillets, blanks for plumbing fixtures, etc.). When coating isapplied to long-length parts (pipes, rods), the appropriateproduction equipment is required.5.1.2 The products shall have neither
23、 pockets nor closedcavities. All cavities shall be available for applying the coatingof diffusion mixture. Should it be impossible to apply thecoating to individual portions of surface of the article, thedocuments shall specify if the coating is allowed to be absentin these cavities.5.1.3 The fasten
24、ers to be coated with zinc shall meet therequirements of standards in force, for the fasteners, andaccompanied with certificates from manufacturers.5.1.4 The products (parts) containing soft solder or resinscan not be coated with zinc.5.1.5 For FastenersThe maximum deviations of threadsprior to appl
25、ication of the coating shall comply with thestandards for threads. An additional gap for the coating forexternal and internal threads separately or for both threads atthe same time, is to be provided, if the coating with increasedthickness is to be applied. Requirements for fasteners to bethermal di
26、ffusion coated with zinc are found in SpecificationsF 2329 and F 2674.5.2 Requirements for material and surface of substrate:5.2.1 This is applied to products of standard-quality carbonsteel, high-quality structural carbon and low-carbon steel, aswell as low-alloyed steel, stainless steels, pig iron
27、 and copper.5.2.2 The following defects are not allowed on the surfacesof the parts:5.2.2.1 Rolled-in scale, burrs;5.2.2.2 Separation into layers and cracks including thosearising from pickling, polishing and other treatment;5.2.2.3 Corrosion damages, pores, and holes.5.2.3 The surfaces of cast and
28、forged products shall be freeof blow and shrink holes, slag, and flux contamination.5.2.4 The surfaces of the parts of hot-rolled metal shall becleaned from scale, pickling sludge, products of corrosion ofthe base metal, and other contamination.5.2.5 After machining, the surfaces of the parts shall
29、be freeof visible layer of grease, emulsion, metallic chips, burrs, dustand products of corrosion, and implantation of foreign metalparticles.5.2.6 Sharp corners and edges of the products except forthose required for technological reasons shall be machined to aradius of at least 0.001 in. 0.3 mm.5.2
30、.7 After heat treatment, the surfaces of the parts shall befree of blow holes, corrosion centers, separation into layers,and buckling.5.2.8 Welds, soldered and brazed joints on the parts shall bescraped bright and continuous over the whole perimeter.5.2.9 Prior to applying the coating, the surface o
31、f the partshall be degreased (chemically or thermally), cleaned bypickling or abrasive blasting.5.2.10 The degree of cleanness of the surface shall be inaccordance with Practice D 6386.5.2.11 The term for storage of the parts with the surfaceprepared for coating with zinc shall not exceed 24 hours u
32、nderconditions excluding the precipitation of a condensate.5.2.12 For applying coatings, the zinc powder with humid-ity of not more than 1.5 % in accordance with Test MethodsD 521 shall be used.6. Chemical Composition6.1 The method described results in the formation of iron-zinc compound layers know
33、n as Gamma (Solid Zn ions insideFe substrate), Delta (Fe11Zn40), and Zeta (FeZn7), excludingthe external Eta layer of pure free zinc.6.2 The zinc mixture used in the thermo-diffusion coatingprocess shall contain a mass fraction not less than 94 % ofmetallic zinc and total impurities (other than Zinc
34、 oxide) of notmore than 2 % mass fraction.A 1059/A 1059M 0826.3 It should be noted that there is evidence this coating issubject to premature red staining in atmospheric and acceler-ated test environments; however, this staining has been foundnot to be associated with corrosion of the substrate stee
35、l, butrather superficial oxidation of the zinc/iron ions present on thesurface.7. Workmanship, Finish and Appearance7.1 Appearance of the coating:7.1.1 The coating shall be flat gray, smooth, and reasonablyuniform. Smoothness of surface is a relative term. Minorroughness that does not interfere with
36、 the intended use of thepart, or roughness that is related to the as-received (un-coated)surface condition of the part, shall not be grounds for rejection.7.1.2 The coating shall be free of swellings, blow holes,cuts, flaking, and embedded quartz sand.7.1.3 The presence of dark gray spots (variation
37、 in the colorof the coating without variation in its thickness) not more than5 % of the total surface of the product is allowed on thecoating.7.1.4 The presence of surface scratches, marks from contactof the part with one another, contact with measuring tools, etc.,without damage to the coating, whi
38、ch would cause exposure ofthe base metal, is allowed.7.1.5 The presence of residual process mixture on thesurface of the part is not allowed.7.1.6 The thickness of the coating depending on the condi-tions of operations of the product shall be specified in thestandards of specification for the produc
39、t in accordance withTable 1.8. Sampling8.1 Test specimens shall be selected randomly from eachinspection lot.8.2 The method of selection and sample size shall be agreedupon between the applicator and the purchaser. Otherwise, thesample size selected from each lot shall be as follows:Batch Size (Piec
40、es) Sample Size1to3 All4to500 3501 to 1200 51201 to 3200 83201 to 10 000 13Above 10 000 209. Number of Tests and Retests9.1 The zinc coating applied shall be tested for appearanceand thickness.9.2 Each lot of parts coated with zinc shall be presented fortesting. A lot shall be considered as a group
41、of articles of thesame type and size coated with zinc within the same productioncycle.9.3 Approximately 10 % of articles per lot and each articlein case of single-unit production shall be examined for appear-ance.9.4 At least three articles per lot shall be tested for thicknessof the coating.9.5 Whe
42、n using the metallographic (arbitration) method, itis allowed to test the coating thickness on one part per lot.9.6 The coating thickness shall be tested prior to theadditional treatment of the coating (applying preservationlubricants, etc.). This measurement shall be taken on a non-threaded section
43、 of the part.9.7 The coating thickness on the threaded portion of a boltshall not be tested but shall be ensured by the correctness of thecoating application technology. When developing the coatingprocess it is recommended to take into account the ISOrequirements for threaded fasteners.9.8 The check
44、ed thickness of the coating shall be acceptedas an arithmetical mean of the measured values.9.9 Should the results of the measuring of the test control beunsatisfactory, the test shall be repeated on double quantity ofparts.10. Specimen Preparation10.1 Specimens for testing should not go through any
45、cleaning process and should be tested as is after the finalcoating process (including passivation and or other top coats).11. Test Methods11.1 Coating appearance check: The coating appearanceshall be checked visually with an unaided eye from the distanceof 10 in. 25 cm from the surface. The luminanc
46、e shall be atleast 300Lx.11.2 Coating thickness testing:11.2.1 Magnetic Method:11.2.1.1 The method is based on the registration of variationin the magnetic resistance depending on the coating thicknessTABLE 1 Thickness or Weight Mass of Zinc Coating for Various Coating ClassesCoating Class Weight Ma
47、ss of Coating, oz/ft2(g/m2) of Surface, Minimum Coating Thickness, mils (m), Minimum130 3.02 (922) 5.14 (130)110 2.50 (765) 4.33 (110)90 2.05 (627) 3.54 (90)80 1.82 (557) 3.15 ( 80)70 1.59 (487) 2.76 (70)65 1.48 (453) 2.56 (65)55 1.25 (383) 2.17 (55)50 1.14 (348) 1.97 (50)45 1.02 (313) 1.77 (45)40 0
48、.91 (278) 1.57 (40)25 0.57 (174) 0.98 (25)12 0.27 (84) 0.47 (12)A 1059/A 1059M 083in accordance with Practice E 376. The magnetic thicknessgauges shall be used as measuring instruments.11.2.1.2 The arithmetic mean of at least three measuredvalues at edges and center of the surface of one article to
49、becontrolled shall be considered as the result of the coatingthickness measurement.11.2.2 Metallographic Method (Arbitration)The methodis based on the measurement of the coating thickness on thecross-section metallographic specimen using metallographicmicroscopes of various types in accordance with Test MethodB 487. The specimen shall be cut from a coated article. Thethickness of the zinc coating shall be measured on thespecimen at least at five point located at equal distances withina linear area with the length of about 0.4 in. 1 cm. Thearithmetic mean o
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