1、Designation: B 695 04Standard Specification forCoatings of Zinc Mechanically Deposited on Iron and Steel1This standard is issued under the fixed designation B 695; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript 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. Scope1.1 This specification covers the requirements
3、for a coatingof zinc mechanically deposited on iron and steel basis metals.The coating is provided in several thicknesses up to andincluding 107 m. The seven thickest classes are usuallyreferred to as “mechanically galvanized.”1.2 This standard does not purport to address all of thesafety concerns,
4、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.NOTE 1The performance of this coating complies with the require-ments of Specification A
5、 153/A 153M and MIL-C-81562.1.3 The values stated in SI units are to be regarded as thestandard. The inch-pound equivalents of SI units are given forinformational purposes.2. Referenced Documents2.1 ASTM Standards:2A 153/A 153M Specification for Zinc Coating (HotDip)on Iron and Steel HardwareA 194/A
6、 194M Specification for Carbon and Alloy SteelNuts for Bolts for High Pressure or High TemperatureService, or BothA 325 Specification for Structural Bolts, Steel, HeatTreated, 120/105 ksi Minimum Tensile StrengthA 490 Specification for Heat-Treated, Steel StructuralBolts, 150 ksi Minimum Tensile Str
7、engthA 563 Specification for Carbon and Alloy Steel NutsB 117 Practice for Operating Salt Spray (Fog) ApparatusB 183 Practice for Preparation of Low-Carbon Steel forElectroplatingB 242 Practice for Preparation of High-Carbon Steel forElectroplatingB 322 Guide for Cleaning Metals Prior to Electroplat
8、ingB 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of aCross SectionB 499 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB 571 Practice for Qualitative Adhesion Testing of Meta
9、llicCoatingsB 602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB 697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB 762 Test Method of Variables Sampling of Metallic andInorganic CoatingsF 1470 Guide for Fastener Sampli
10、ng for Specified Mechani-cal Properties and Performance Inspection2.2 Military Standard:MIL-C-81562 Coating, Cadmium, Tin Cadmium and Zinc(Mechanically Deposited)32.3 AISC Standard:Specifications for Structural Joints Using ASTM A 325 orA 490 Bolts43. Classification3.1 ClassesZinc coatings are class
11、ified on the basis ofthickness, as follows:Class Minimum Thickness, m110 10780 8170 6965 6655 5350 5040 4025 2512 1288553.2 TypesZinc coatings are identified by types on thebasis of supplementary treatment required, as follows:1This specification is under the jurisdiction of ASTM Committee B08 onMet
12、allic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.08.04 on Light Metals.Current edition approved Aug. 1, 2004. Published August 2004. Originallyapproved in 1982. Last previous edition approved in 2000 as B 695 00.2For referenced ASTM standards, visit the ASTM website,
13、www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 1
14、9111-50984Available from American Institute of Steel Construction (AISC), One E.Wacker Dr., Suite 3100, Chicago, IL 60601-2001.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Type IAs coated, without supplementary treatment (Ap-pendi
15、x X2.1).Type IIWith colored chromate conversion treatment (Ap-pendix X2.2).4. Ordering Information4.1 Supplying the following information by the purchaser tothe seller in the purchase order or other governing documentwill make the application of this specification complete:4.1.1 Class, including a m
16、aximum thickness, if appropriate,type, and for Type II, color and need for supplemental lubricant(3.1, 3.2, and 6.2.5),4.1.2 Nature of substrate (for example, high-strength steel),need for stress relief (6.2.1), and cleaning precautions to befollowed (6.2.2 and 6.2.3),4.1.3 Significant surfaces (6.3
17、),4.1.4 Requirements for and methods of testing for one ormore of the following, if required: need for and type of testspecimens (8.1), thickness (6.3 and 8.3), adhesion (6.4 and8.4), corrosion resistance (6.5 and 8.5), absence of hydrogenembrittlement, and the waiting period before testing and test
18、ingloads (6.6 and 8.6),4.1.5 Inspection responsibility (Section 11) and samplingplan for each inspection criterion (Section 7), and4.1.6 Requirements for certified report of test results (Sec-tion 10).5. Workmanship5.1 The coating shall be uniform in appearance and free ofblisters, pits, nodules, fl
19、aking, and other defects that arecapable of adversely affecting the function of the coating. Thecoating shall cover all surfaces as stated in 6.3 including rootsof threads, thread peaks, corners, recesses, and edges. Thecoating shall not be stained or discolored throughout to anextent capable of adv
20、ersely affecting appearance as a func-tional requirement. However, superficial staining, that resultsfrom rinsing or drying, and variations in color or luster shallnot be cause for rejection.NOTE 2The nature of the mechanical plating process is such thatcoatings characteristically will not be as smo
21、oth or as bright as someelectroplated coatings.6. Requirements6.1 AppearanceThe coating as deposited shall have auniform silvery appearance, and a matte to medium-brightluster.6.2 Process:6.2.1 Stress-Relief TreatmentAll steel parts that have anultimate tensile strength of 1000 MPa and above and tha
22、tcontain tensile stresses caused by machining, grinding,straightening, or cold-forming operation shall be given astress-relief heat treatment prior to cleaning and metal deposi-tion. The temperature and time at temperature shall be 190 615C for a minimum of3hsothat maximum stress relief isobtained w
23、ithout reducing the hardness below the specifiedminimum.6.2.2 High-strength steels (which become embrittled whencharged with hydrogen) and that have heavy oxide or scaleshall be cleaned before application of the coating in accordancewith Practice B 242. In general, nonelectrolytic alkaline,anodic-al
24、kaline, and some inhibited acid cleaners are preferredto avoid the risk of producing hydrogen embrittlement from thecleaning procedure.6.2.3 For low-carbon steels, see Practice B 183. Usefulguidelines are also given in Guide B 322.6.2.4 Mechanical deposition of zinc coatings shall consist,in general
25、, of all of the steps listed below, and in the sequenceas shown:6.2.4.1 Preparation of the surface of the parts to be coated,by chemical (generally acidic) procedure to an extent thatpermits uniformly satisfactory results from subsequent steps.6.2.4.2 Deposition of a thin metal coating, generally of
26、copper, by immersion in appropriate chemical solutions, with-out the use of electric current. There are no thickness require-ments for this coating.6.2.4.3 Tumbling of the parts that have been treated accord-ing to 6.2.4.1 and 6.2.4.2 in a container with the following:(1) The zinc metal to be deposi
27、ted, in powder form;(2) Impact media, which includes glass, for example, orother substances that are essentially inert to the chemicals ofthe deposition process. The function of this media is to aid inproviding mechanical forces to drive the metal powder onto thesubstrate parts;(3) A “promoter” or “
28、accelerator” which aids in theuniform deposition of the metal powder; and(4) A liquid medium, generally water.6.2.4.4 Separation of the parts from the solid and liquidmedia.6.2.4.5 Rinsing.6.2.4.6 Drying.6.2.5 Supplementary Treatments:6.2.5.1 Colored Chromate Conversion Treatments (TypeII)Colored ch
29、romate conversion treatment for Type II shallbe done in a solution containing hexavalent chromium ions.This solution shall produce a bright or semi-bright continuous,smooth, protective film with a uniform color that is capable ofranging from yellow through bronze and olive-drab to brownand black and
30、 that are capable of being dyed to a desired color.Bright dips that do not contain salts that yield films containinghexavalent chromium ions are precluded as treatments forproducing Type II coatings.6.2.5.2 Waxes, lacquers, or other organic coatings are notprohibited from being used to improve lubri
31、city, and the needfor them shall be supplied in the purchase order or othergoverning document (see 4.1.1). Supplemental lubricationtreatments shall not be used to ensure conformance to the saltspray corrosion resistance requirements (see 8.5.4).6.2.5.3 Lubrication of grade DH nuts processed in accor
32、-dance with this specification and used with Specification A 325high-strength bolts is a requirement of paragraph 6.5 ofSpecification A 325 and paragraph 4.8 of Specification A 563.NOTE 3Although not included in Specification A 194/A 194M, thisprovision should apply to mechanically galvanized A 194
33、2H nuts whensupplied for use with Specification A 325 bolts.NOTE 4Specifications for structural joints using Specification A 325or A 490 bolts references the use of lubricants on nuts to be used withSpecification A 325 high-strength bolts and is found in the commentary onB695042this RCSC (Research C
34、ouncil on Structural Connections of the Engineer-ing Foundation) Specification, within the paragraphs entitled “Effect OfGalvanizing Upon Torque Involved In Tightening” and “Shipping Re-quirements For Galvanized Bolts and Nuts,” published November 1985,page 30.46.2.6 Surface DefectsDefects and varia
35、tions in appear-ance in the coating that arise from surface conditions of thesubstrate (scratches, pores, roll marks, inclusions, etc.) and thatpersist in the finish despite the observance of good metalfinishing practices shall not be cause for rejection.NOTE 5Applied finishes generally perform bett
36、er in service when thesubstrate over which they are applied is smooth and free of torn metal,inclusions, pores, and other defects. It is recommended that the specifi-cations covering the unfinished product provide limits for these defects. Ametal finisher can often remove defects through special tre
37、atments, suchas grinding, polishing, abrasive blasting, chemical treatments, and elec-tropolishing. However, these are not normal in the treatment stepspreceding the application of the finish. When desired they must bespecified on the purchase order (4.1.2).6.3 Thickness:6.3.1 The thickness of the c
38、oating everywhere on thesignificant surfaces shall be at least that of the specified classas defined in 3.1.6.3.2 Significant surfaces are defined as those normallyvisible (directly or by reflection) that are essential to theappearance or serviceability of the article when assembled innormal positio
39、n; or that are capable of providing the source ofcorrosion products that deface visible surfaces on the as-sembled article. When necessary, the significant surfaces shallbe indicated on the drawing for the article, or by the provisionof suitably marked samples.NOTE 6The thickness of mechanically-dep
40、osited coatings varies frompoint-to-point on the surface of a product, characteristically tending to bethicker on flat surfaces and thinner at exposed edges, sharp projections,shielded or recessed areas, interior corners and holes, with such thinnerareas often being exempted from thickness requireme
41、nts.6.3.3 When significant surfaces are involved on which thespecified thickness of deposit cannot readily be controlled, it isincumbent upon the purchaser and manufacturer to recognizethe necessity for either thicker or thinner deposits. For ex-ample, to reduce buildup in thread roots, holes, deep
42、recesses,bases of angles, and similar areas, the deposit thickness on themore accessible surfaces will have to be reduced proportion-ately.NOTE 7The coating thickness requirement of this specification is aminimum requirement; that is, the coating thickness is required to equal orexceed the specified
43、 thickness everywhere on the significant surfaces.Variation in the coating thickness from point to point on a coated articleis an inherent characteristic of mechanical deposition processes. There-fore, the coating thickness will have to exceed the specified value at somepoints on the significant sur
44、faces to ensure that the thickness equals orexceeds the specified value at all points. Hence, in most cases, the averagecoating thickness on an article will be greater than the specified value;how much greater is largely determined by the shape of the article and thecharacteristics of the deposition
45、 process.In addition, the average coating thickness on articles will vary fromarticle to article within a production lot. Therefore, if all of the articles ina production lot are to meet the thickness requirement, the average coatingthickness for the production lot as a whole will be greater than th
46、e averagenecessary to ensure that a single article meets the requirement.6.4 AdhesionThe zinc coating shall be sufficiently adher-ent to the basis metal to pass the tests specified in 8.4.6.5 Corrosion Resistance:6.5.1 The presence of corrosion products visible to theunaided eye at normal reading di
47、stance at the end of thespecified test periods stated in Table 1 shall constitute failure,except that corrosion products at edges of specimens shall notconstitute failure. Slight “whisps” of white corrosion, asopposed to obvious accumulations, shall be acceptable.NOTE 8Mechanical deposition is exclu
48、sively a barrel-finishing pro-cess. It is recognized that mechanical deposition on parts may thereforeproduce surfaces that have a different characteristic from those on partsthat are finished exclusively by racking. Similarly, corrosion testing ofactual parts may produce different results from thos
49、e on test panels. Saltspray requirements that are appropriate to indicate the technical qualitywith which a process is carried out may be impractical for acceptance ofactual parts. In such cases the purchaser shall indicate his requirements onthe purchase order (4.1.4).NOTE 9In many instances, there is no direct relation between theresults of an accelerated corrosion test and the resistance to corrosion inother media, because several factors that influence the progress ofcorrosion, such as the formation of protective films, vary greatly with theconditions encount
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