Designation:A1059/A1059M−08
Standard Specification for
Zinc Alloy Thermo-Diffusion Coatings(TDC)on Steel Fasteners,Hardware,and Other Products1
This standard is issued under thefixed designation A1059/A1059M;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(´)indicates an editorial change since the last revision or reapproval.
1.Scope
1.1This specification covers the general requirements for protective zinc coatings(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 and high tensile parts as well as of wrought iron,sintered iron steel-powder and various steel and stainless alloys.TDC is carried out by immersing the parts in a zinc alloy powder at elevated temperature for a period of time,causing a metallur-gical diffusion process of zinc and iron.Further processing may be added,such as,passivation,topcoat application,paint application,etc.
1.2This specification is applicable to orders in either inch-pound units(as A1059)or in SI units(as A1059M). Inch-pound units and SI units are not necessarily exact equivalents.Within the text of this specification and where appropriate,SI units are shown in brackets.Each system shall be ud independently of the other without combining values in any way.In the ca of orders in SI units,all testing and inspection shall be done using the metric equivalent of the test or inspection method as appropriate.In the ca of orders in inch-pound units,such shall be stated to the applicator when the order is placed.
数字媒体艺术设计
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 prac
实践的反义词tices and determine the applica-bility of regulatory limitations prior to u.
2.Referenced Documents
2.1ASTM Standards:2
A90/A90M Test Method for Weight[Mass]of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
A385Practice for Providing High-Quality Zinc Coatings (Hot-Dip)
A700Practices for Packaging,Marking,and Loading Meth-ods for Steel Products for Shipment
A902Terminology Relating to Metallic Coated Steel Prod-ucts
B487Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
D521Test Methods for Chemical Analysis of Zinc Dust (Metallic Zinc Powder)
D6386Practice for Preparation of Zinc(Hot-Dip Galva-nized)Coated Iron and Steel Product and Hard
ware Surfaces for Painting
E376Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current(Electromagnetic)Test-ing Methods
F1789Terminology for F16Mechanical Fasteners
F2329Specification for Zinc Coating,Hot-Dip,Require-ments for Application to Carbon and Alloy Steel Bolts, Screws,Washers,Nuts,and Special Threaded Fasteners F2674Specification for Zinc Coating,Hot-Dip,Require-ments for Application to Carbon and Alloy Steel Bolts, Screws,Washers,Nuts,and Special Threaded Fasteners [Metric]
3.Terminology
3.1The following terms and definitions are specific to this specification.Terminology A902contains other terms and definitions relating to metallic-coated steel products.Terminol-ogy F1789contains other terms and definitions relating to mechanical fasteners.
30万车
3.2Definitions of Terms Specific to This Standard:
3.2.1thermo-diffusion coating—a process where the steel product is heated in clo contact with zinc powder or zinc mixture.
3.2.2thermo-diffusion coating—a coating made by thermo-diffusion coating process,consisting of zinc/iron alloys.
3.2.3zinc powder—the coating material ud to provide corrosion protection to steel.
1This specification is under the jurisdiction of ASTM Committee A05on
Metallic-Coated Iron and Steel Products and is the direct responsibility of
Subcommittee A05.13on Structural Shapes and Hardware Specifications.
光村Current edition approved Nov.15,2008.Published December2008.DOI:
10.1520/A1059_A1059M-08.
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
3.2.4zinc mixture—a combination of zinc powder and other metallic materials to be ud as a coating material in the TDC process.
4.Ordering Information
4.1Orders for coatings provided under this specification shall include the following:
4.1.1Quantity(number of pieces to be coated)and total weight.
4.1.2Description(type and size of products)and weight.
4.1.3ASTM specification designation and year of issue.
4.1.4Material identification(e
白端
5.1)and surface condition or contamination.
4.1.5Sampling plan,if different from Section8.
4.1.6Special test requirements,if different from Section9 (e9.1).
4.1.7Special requirements(special stacking,heavier coat-ing weight,etc.).
4.1.8Tagging or piece identification method.
4.2Additional Information—Additional information may be required in certain circumstances.In the cas the purchar will furnish the applicator with the following additional infor-mation:
4.2.1Any likely effects on the metallurgical properties of the ba material caud by processing temperatures of up to 1092°F[500°C].
4.2.2Determination of areas considered as significant sur-faces.This should be done by drawings or by providing samples with suitable markings.
4.2.3Any critical thickness tolerances,such as when bolts and nuts are ud.This should be done on the product’s drawing or on the purcha order.
4.2.4Any special pre-treatment requirements or the exis-tence of other materials,lubricants,stripping materials,pre-existing corrosion,etc.
4.2.5Whether quality certificate is required or not.
5.Materials and Manufacture
5.1Requirements to design of the products to be coated with zinc are detailed in Practice A385.The following provi-sions are necessary to produce a high quality coating.
5.1.1The products to be coated with zinc include parts and asmblies of various sizes:presswork,forged,cast,machined products(nuts,washers,bolts,nails,chains,small round billets,blanks for plumbingfixtures,etc.).When coating is applied to long-length parts(pipes,rods),the appropriate production equipment is required.
5.1.2The products shall have neither pockets nor clod cavities.All cavities shall be available for applying the coating of diffusion mixture.Should it be impossible to apply the coating to individual portions of surface of the article,the documents shall specify if the coating is allowed to be abnt in the cavities.
5.1.3The fasteners to be coated with zinc shall meet the requirements of standards in force,for the fasteners,and accompanied with certificates from manufacturers.
5.1.4The products(parts)containing soft solder or resins can not be coated with zinc.
5.1.5For Fasteners—The maximum deviations of threads prior to application of the coating shall comply with the standards for threads.An additional gap for the coating for external and internal threads parately or for both threads at the same time,is to be provided,if the coating with incread thickness is to be applied.Requirements for fasteners to be thermal diffusion coated with zinc are found in Specifications F2329and F2674.
5.2Requirements for material and surface of substrate: 5.2.1This is applied to products of standard-quality carbon steel,high-quality structural carbon and low-carbon steel,as well as low-alloyed steel,stainless steels,pig iron and copper.
5.2.2The following defects are not allowed on the surfaces of the parts:
5.2.2.1Rolled-in scale,burrs;
5.2.2.2Separation into layers and cracks including tho arising from pickling,polishing and other tre
atment;
5.2.2.3Corrosion damages,pores,and holes.
5.2.3The surfaces of cast and forged products shall be free of blow and shrink holes,slag,andflux contamination.
5.2.4The surfaces of the parts of hot-rolled metal shall be cleaned from scale,pickling sludge,products of corrosion of the ba metal,and other contamination.
5.2.5After machining,the surfaces of the parts shall be free of visible layer of grea,emulsion,metallic chips,burrs,dust and products of corrosion,and implantation of foreign metal particles.
5.2.6Sharp corners and edges of the products except for tho required for technological reasons shall be machined to a radius of at least0.001in.[0.3mm].
5.2.7After heat treatment,the surfaces of the parts shall be free of blow holes,corrosion centers,paration into layers, and buckling.
5.2.8Welds,soldered and brazed joints on the parts shall be scraped bright and continuous over the whole perimeter.
5.2.9Prior to applying the coating,the surface of the part shall be degread(chemically or thermally),cleaned by pickling or abrasive blasting.
5.2.10The degree of cleanness of the surface shall be in accordance with Practice D638
6.
5.2.11The term for storage of the parts with the surface prepared for coating with zinc shall not exceed24hours under conditions excluding the precipitation of a condensate.
5.2.12For applying coatings,the zinc powder with humid-ity of not more than1.5%in accordance with Test Methods D521shall be ud.
6.Chemical Composition
6.1The method described results in the formation of iron-zinc compound layers known as Gamma(Solid Zn ions inside Fe substrate),Delta(Fe11Zn40),and Zeta(FeZn7),excluding the external Eta layer of pure free zinc.
6.2The zinc mixture ud in the thermo-diffusion coating process shall contain a mass fraction not less than94%of metallic zinc and total impurities(other than Zinc oxide)of not more than2%mass
fraction.
6.3It should be noted that there is evidence this coating is subject to premature red staining in atmospheric and acceler-ated test environments;however,this staining has been found not to be associated with corrosion of the substrate steel,but rather superficial oxidation of the zinc/iron ions prent on the surface.
7.Workmanship,Finish,and Appearance家常肉末茄子
7.1Appearance of the coating:
7.1.1The coating shall be flat gray,smooth,and reasonably uniform.Smoothness of surface is a relative term.Minor roughness that does not interfere with the intended u of the part,or roughness t
hat is related to the as-received (un-coated)surface condition of the part,shall not be grounds for rejection.7.1.2The coating shall be free of swellings,blow holes,cuts,flaking,and embedded quartz sand.
7.1.3The prence of dark gray spots (variation in the color of the coating without variation in its thickness)not more than 5%of the total surface of the product is allowed on the coating.
7.1.4The prence of surface scratches,marks from contact of the part with one another,contact with measuring tools,etc.,without damage to the coating,which would cau exposure of the ba metal,is allowed.
7.1.5The prence of residual process mixture on the surface of the part is not allowed.
7.1.6The thickness of the coating depending on the condi-tions of operations of the product shall be specified in the standards of specification for the product in accordance with Table 1.8.Sampling
8.1Test specimens shall be lected randomly from each inspection lot.
8.2The method of lection and sample size shall be agreed upon between the applicator and the purchar.Otherwi,the sample size lected from each lot shall be as follows:
Batch Size (Pieces)Sample Size 1to 3All 4to 5003501to 120051201to 320083201to 1000013Above 10000
20
9.Number of Tests and Retests
9.1The zinc coating applied shall be tested for appearance and thickness.
9.2Each lot of parts coated with zinc shall be prented for testing.A lot shall be considered as a group of articles of the same type and size coated with zinc within the same production cycle.
9.3Approximately 10%of articles per lot and each article in ca of single-unit production shall be examined for appear-ance.
9.4At least three articles per lot shall be tested for thickness of the coating.
9.5When using the metallographic (arbitration)method,it is allowed to test the coating thickness on one part per lot.9.6The coating thickness shall be tested prior to the additional treatment of the coating (applying prervation lubricants,etc.).This measurement shall be taken on a non-threaded ction of the part.
9.7The coating thickness on the threaded portion of a bolt shall not be tested but shall be ensured by the correctness of the coating application technology.When developing the coating process it is recommended to take into account the ISO requirements for threaded fasteners.
9.8The checked thickness of the coating shall be accepted as an arithmetical mean of the measured values.
9.9Should the results of the measuring of the test control be unsatisfactory,the test shall be repeated on double quantity of parts.
10.Specimen Preparation
10.1Specimens for testing should not go through any cleaning process and should be tested as is after the final coating process (including passivation and or other top coats).11.Test Methods
11.1Coating appearance check:The coating appearance shall be checked visually with an unaided eye from the distance of 10in.[25cm]from the surface.The luminance shall be at least 300Lx.
11.2Coating thickness testing:
TABLE 1Thickness or Weight [Mass]of Zinc Coating for Various Coating Class
Coating Class Weight [Mass]of Coating,oz/ft 2(g/m 2)of Surface,Minimum Coating Thickness,mils (µm),Minimum 130 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)400.91(278) 1.57(40)250.57(174)0.98(25)12
0.27(84)
0.47
(12)
11.2.1Magnetic Method:
11.2.1.1The method is bad on the registration of variation in the magnetic resistance depending on the coating thickness in accordance with Practice E376.The magnetic thickness gauges shall be ud as measuring instruments.
11.2.1.2The arithmetic mean of at least three measured values at edges and center of the surface of one article to be controlled shall be considered as the result of the coating thickness measurement.
11.2.2Metallographic Method(Arbitration)—The method is bad on the measurement of the coating thickness on the cross-ction metallographic specimen using metallographic microscopes of various types in accordance with Test Method B487.The specimen shall be cut from a coated article.The thickness of the zinc coating shall be measured on the specimen at least atfive point located at equal distances within a linear area with the length of about0.4in.[1cm].The arithmetic mean of all measured values shall be considered as the result.
11.2.3Gravimetric Method—The gravimetric method shall be ud for determining the mean thickness of the coating.The method consists of weighing the reprentative specimens before and after applying the coating and then before and removing the coating in accordance with Test Method A90/ A90M.
12.Certification
12.1When specified in the purcha order or contract,the purchar shall be furnished certification that samples repre-nting each inspection lot have been either tested or inspected as directed by th
is specification and the requirements have been met.When specified in the purcha order or contract,a report of the test results shall be furnished.
13.Packaging and Package Marking
擦肩而过歌词13.1Unless specified otherwi by the customer in the purcha order,the coated products shall be packaged,trans-ported and stored in accordance with Practices A700.
14.Keywords
14.1coatings,zinc;fasteners,zinc coated;iron products, zinc coated;steel hardware,zinc coated;steel products,metal-lic coated;zinc coatings,steel products
APPENDIX
(Nonmandatory Information)
X1.COATING CHARACTERISTICS
授课方式X1.1The thermo diffusion zinc coating is anodic in relation to ferrous metals and provides for electrochemical protection of steel against corrosion.
X1.2Thermo diffusion results in a hard surface,usually exceeding35Rockwell C,depending on coating parameters.
X1.3Thermo diffusion does not create hydrogen embrittle-ment
X1.4Due to some porosity on the surface of the coating, thermo diffusion coated parts have excellent bonding charac-teristics with various topcoats and paint system.
X1.5The thermo-diffusion zinc coating is obtained by heating the parts in a container with the diffusion mixture consisting of zinc powder and some alloying elements.The working temperatures of applying the coating normally range between710°F to1092°F[320°C to500°C].
X1.6Since the coating application process has a sufficiently long duration,the thermo diffusion coating with zinc can be ud for parts made of materials that do not change their properties at the temperatures.
X1.7The coating obtained shall follow exactly the contours of the article,its thickness shall be very uniform over the whole surface of the part including complex-shaped articles(threaded connections,etc.).
X1.8When applying the coating,the part shall be placed in a container.Since the size of the parts is restricted by the size of the container,the appropriate size container must be ud. X1.9The coating has strong adhesion to ba metal due to mutual diffusion of zinc and iron.Zinc penetrates the ba metal to about1⁄3of the coating thickness.
X1.10The coating consists mainly of the iron-zinc d1-pha containing4to10%of iron.
X1.11Due to the prence of iron in the coating,red stains or brown spots may appear on the surface of the coated article under the influence of incread humidity or condensate.It is caud by the relea of iron ions from the coating.The ions are washed away easily by water
X1.12Should it be impossible to distinguish the corrosion products of the coating and that of ba metal,the prence of the coating shall be checked by metallographic method and mass loss
testing.
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