1、Designation: B695 04 (Reapproved 2009)Standard Specification forCoatings of Zinc Mechanically Deposited on Iron and Steel1This standard is issued under the fixed designation B695; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 th
3、e requirements 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 thesa
4、fety 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.NOTE 1The performance of this coating complies with the require-ments of
5、Specification A153/A153M 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:2A153/A153M Specification for Zinc Coating (Hot-Dip) onIron and Steel Har
6、dwareA194/A194M Specification for Carbon and Alloy SteelNuts for Bolts for High Pressure or High TemperatureService, or BothA325 Specification for Structural Bolts, Steel, Heat Treated,120/105 ksi Minimum Tensile StrengthA325 Specification for Structural Bolts, Steel, Heat Treated,120/105 ksi Minimu
7、m Tensile Strength2.2 MIL Standard3MIL-C-81562 Coatings, Cadmium, TinCadium andZinc (Mechanically Deposited)3. Classification3.1 ClassesZinc coatings are classified on the basis ofthickness, as follows:Class Minimum Thickness, m110 10780 8170 6965 6655 5350 5040 4025 2512 1288553.2 TypesZinc coating
8、s are identified by types on thebasis of supplementary treatment required, as follows:Type IAs coated, without supplementary treatment (Ap-pendix X2.1).Type IIWith colored chromate conversion treatment (Ap-pendix X2.2).4. Ordering Information4.1 Supplying the following information by the purchaser t
9、othe seller in the purchase order or other governing documentwill make the application of this specification complete:4.1.1 Class, including a maximum 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 exampl
10、e, 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),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
11、.3), adhesion (6.4 and1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.08.04 on Soft Metals.Current edition approved Sept. 1, 2009. Published December 2009. Originallyapproved in 1982. Last previ
12、ous edition approved in 2004 as B695 04. DOI:10.1520/B0695-04R09.2For referenced ASTM standards, visit the ASTM website, 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 webs
13、ite.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-50981Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.4), corrosion resistance (6.5 and 8.5), absence of hy
14、drogenembrittlement, and the waiting period before testing and testingloads (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 sh
15、all be uniform in appearance and free ofblisters, pits, nodules, flaking, 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
16、 not be stained or discolored throughout to anextent capable of adversely 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
17、 process is such thatcoatings characteristically will not be as smooth 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
18、that have anultimate tensile strength of 1000 MPa and above and thatcontain 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 1
19、90 615C for a minimum of3hsothat maximum stress relief isobtained without 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 accordance
20、with Practice . In general, nonelectrolytic alkaline, anodic-alkaline, and some inhibited acid cleaners are preferred toavoid the risk of producing hydrogen embrittlement from thecleaning procedure.6.2.3 For low-carbon steels, see Practice . Useful guidelinesare also given in Guide .6.2.4 Mechanical
21、 deposition of zinc coatings shall consist,in general, 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
22、.4.2 Deposition of a thin metal coating, generally ofcopper, 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 contain
23、er with the following:(1) The zinc metal to be deposited, 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
24、 powder onto thesubstrate parts;(3) A “promoter” or “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 Colo
25、red Chromate Conversion Treatments (TypeII)Colored chromate 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 yello
26、w through bronze and olive-drab to brownand black and 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 coatin
27、gs are notprohibited from being used to improve lubricity, 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.
28、2.5.3 Lubrication of grade DH nuts processed in accor-dance with this specification and used with Specification A325high-strength bolts is a requirement of paragraph 6.5 ofSpecification A325 and paragraph 4.8 of Specification .NOTE 3Although not included in Specification A194/A194M, thisprovision sh
29、ould apply to mechanically galvanized Specification A194/A194M 2H nuts when supplied for use with Specification A325 bolts.NOTE 4Specifications for structural joints using Specification A325or A325 bolts references the use of lubricants on nuts to be used withSpecification A325 high-strength bolts a
30、nd is found in the commentary onthis RCSC (Research Council 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
31、 1985,page 30.46.2.6 Surface DefectsDefects and variations 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 re
32、jection.NOTE 5Applied finishes generally perform better 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
33、finisher can often remove defects through special treatments, suchas grinding, polishing, abrasive blasting, chemical treatments, and elec-tropolishing. However, these are not normal in the treatment steps4Available from American Institute of Steel Construction (AISC), One E.Wacker Dr., Suite 700, C
34、hicago, IL 60601-2001, http:/www.aisc.org.B695 04 (2009)2preceding 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 coating everywhere on thesignificant surfaces shall be at least that of the specified classas de
35、fined 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 position; or that are capable of providing the source ofcorrosion products that deface visible surface
36、s 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-deposited coatings varies frompoint-to-point on the surface of a product, characteristically tendi
37、ng 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 requirements.6.3.3 When significant surfaces are involved on which thespecified thickness of deposit can
38、not 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 recesses,bases of angles, and similar areas, the deposit thickness on themore accessible surfac
39、es 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 thickness everywhere on the significant surfaces.Variation in the coating thickness from point
40、 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 surfaces to ensure that the thickness equals orexceeds the specified value at all points. Hence, i
41、n 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 process.In addition, the average coating thickness on articles will vary fromarticle to articl
42、e 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 the averagenecessary to ensure that a single article meets the requirement.6.4 AdhesionThe zinc c
43、oating 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 distance at the end of thespecified test periods stated in Table 1 shall constitute failure,excep
44、t 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 exclusively a barrel-finishing pro-cess. It is recognized that mechanical deposition on parts may th
45、ereforeproduce 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 those on test panels. Saltspray requirements that are appropriate to indicate the technical quality
46、with 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 t
47、o corrosion inother media, because several factors that influence the progress ofcorrosion, such as the formation of protective films, vary greatly with theconditions encountered. The results obtained in the test should not,therefore, be regarded as a direct guide to the corrosion resistance of thet
48、ested materials in all environments where these materials may be used.Also, performance of different materials in the test cannot always be takenas a direct guide to the relative corrosion resistance of these materials inservice.6.5.2 On parts with Type II coatings, the greater number ofhours for ei
49、ther white corrosion products or rust shall apply.For example, for Type II, Class 8, the test shall be continueduntil the 72-h requirement is met for white corrosion products;similarly, for Type II, Class 25, if no white corrosion productsappear before 72 h, test shall be continued until the 192-hrequirement for basis metal corrosion is met (8.5.2).6.6 Absence of Hydrogen EmbrittlementSprings and otherhigh-strength parts subject to flexure shall be held for aminimum of 48 h at room temperature after coating beforebeing loaded, flexed, or used. Such high-stren
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1