ASTM B635-2000(2009) Standard Specification for Coatings of Cadmium-Tin Mechanically Deposited《镉锡机械沉积镀层标准规范》.pdf

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1、Designation: B635 00 (Reapproved 2009)Standard Specification forCoatings of Cadmium-Tin Mechanically Deposited1This standard is issued under the fixed designation B635; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la

2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for a coatingthat is a mixture of cadmium and tin mechanically deposited onme

3、tal products. The coating is provided in various thicknessesup to and including 12 m.1.2 Mechanical deposition greatly reduces the risk of hy-drogen embrittlement and is suitable for coating bores andrecesses in many parts that cannot be conveniently platedelectrolytically. (See Appendix X1.)1.3 The

4、 values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priat

5、e safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardsstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray (Fog) ApparatusB183 Practice for Preparation of Low-Carbon Steel forE

6、lectroplatingB201 Practice for Testing Chromate Coatings on Zinc andCadmium SurfacesB242 Guide for Preparation of High-Carbon Steel for Elec-troplatingB322 Guide for Cleaning Metals Prior to ElectroplatingB487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examinati

7、on of CrossSectionB499 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB567 Test Method for Measurement of Coating Thicknessby the Beta Backscatter MethodB571 Practice for Qualitative Adhesion Testing of MetallicCoatingsB602 Tes

8、t Method for Attribute Sampling of Metallic andInorganic CoatingsB697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB762 Test Method of Variables Sampling of Metallic andInorganic CoatingsE87 Methods for Chemical Analysis of Lead, Tin, Anti-mo

9、ny, and Their Alloys (Photometric Methods)3E396 Test Methods for Chemical Analysis of CadmiumF1470 Practice for Fastener Sampling for Specified Me-chanical Properties and Performance Inspection2.2 U.S. Federal Standard:FED-STD-141 Paint, Varnish, Lacquer, and Related Mate-rials; Methods of Inspectio

10、n, Sampling and Testing42.3 U.S. Military Standard:MIL-L-7808J Lubricating Oil, Aircraft Turbine Engine,Synthetic Base43. Classification3.1 ClassesCadmium-tin coatings are classified on thebasis of thickness, as follows:Class Minimum Thickness, m12 1288553.2 TypesCadmium-tin coatings are identified

11、by types onthe basis of supplementary treatment required, as follows:3.2.1 Type IAs coated, without supplementary chromatetreatment (see X1.1).3.2.2 Type IIWith supplementary chromate treatment (seeX1.2).1This specification is under the jurisdiction of ASTM Committee B08 on and isthe direct responsi

12、bility of Subcommittee B08.08.04 on Soft Metals.Current edition approved Sept. 1, 2009. Published November 2009. Originallyapproved in 1978. Last previous edition approved in 2004 as B635 00(2004)1.DOI: 10.1520/B0635-00R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta

13、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NP

14、ODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Ordering Information4.1 To make the application of this specification complete,the purchaser needs to supply the following information to thesupplier in the purchase order or oth

15、er governing document:4.1.1 Class, including a maximum thickness, if appropriate,type, and need for supplemental lubricant (3.1, 3.2, and5.2.4.2).4.1.2 Nature of substrate, for example, high-strength steel,need for stress-relief, and cleaning precautions to be followed(5.2.2).4.1.3 Significant surfa

16、ces (5.3).4.1.4 Requirements and methods of testing for one or moreof the following requirements: need for and type of testspecimens (8.1), composition (8.2), thickness (8.4), adhesion(8.6), and absence of hydrogen embrittlement and the waitingperiod prior to testing and testing loads (8.8) and lubr

17、icatingresistance (S2).4.1.5 Sampling plan for each inspection criterion and re-sponsibility for inspection, if necessary (Section 6 and Supple-mentary Requirement S1).4.1.6 Requirements for certified report of test results (Sec-tion 10).5. Requirements5.1 Nature of FinishThe coating shall be 45 to

18、75 mass %cadmium, the remainder tin.5.2 Process:5.2.1 Stress Relief TreatmentAll steel parts that haveultimate tensile strength of 1000 MPa and above and thatcontain tensile stresses caused by machining, grinding,straightening, or cold forming operation shall be given a stressrelief heat treatment p

19、rior to cleaning and metal deposition.The temperature and time at temperature shall be 190 6 15Cfor a minimum of3hsothat maximum stress relief is obtainedwithout reducing the hardness below the specified minimum.5.2.2 High-strength steels that have heavy oxide or scaleshall be cleaned before applica

20、tion of the coating in accordancewith Guide B242. In general, non-electrolytic alkaline, anodic-alkaline, and some inhibited acid cleaners are preferred toavoid the risk of producing hydrogen embrittlement from thecleaning procedure.5.2.3 For preparation of low-carbon steels, see PracticeB183. For c

21、leaning, useful guidelines are also given in GuideB322.5.2.4 Supplementary Treatments:5.2.4.1 Chromate treatment for Type II shall be done in asolution containing hexavalent chromium. This solution shallproduce a bright or semi-bright continuous, smooth, protectivefilm. This film may have a slight y

22、ellowish or iridescent color.The absence of color shall not be considered evidence of theabsence of a Type II film or as a basis for rejection of the parts.Only post treatments that contain salts that yield films contain-ing hexavalent chromium are permitted as treatments forproducing Type II coatin

23、gs.5.2.4.2 Waxes, lacquers, or other organic coatings may beused to improve lubricity, and the need for them should besupplied in the purchase order or other governing document(4.1.1). Such supplemental lubrication treatments shall not beused to ensure conformance to the salt spray corrosion resista

24、ntrequirements or to enhance the test results of the lead acetatespot test (8.5.2).5.3 Thickness:5.3.1 The thickness of the coating everywhere on thesignificant surfaces shall be at least that of the specified classas defined in 3.1.5.3.2 Significant surfaces are defined as those normallyvisible (di

25、rectly or by reflection) that are essential to theappearance or serviceability of the article when assembled innormal position; or which can be the source of corrosionproducts that deface visible surfaces on the assembled article.When necessary, the significant surfaces shall be indicated onthe draw

26、ing of the article, or by the provision of suitablymarked samples.NOTE 1The thickness of mechanically-deposited 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 recesse

27、d areas, interior corners and holes, with such thinnerareas often being exempted from thickness requirement.5.3.3 When significant surfaces are involved on which thespecified thickness of deposit cannot readily be controlled, thepurchaser and manufacturer should recognize the necessity foreither thi

28、cker or thinner deposits. For example, to reducebuildup in thread roots, holes, deep recesses, bases of angles,and similar areas, the deposit thickness on the more accessiblesurfaces will have to be reduced proportionately.NOTE 2The coating thickness requirement of this specification is aminimum req

29、uirement; 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 to point on a coated articleis an inherent characteristic of mechanical deposition processes. There-fore, the coating th

30、ickness 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. Thus, in most cases, the averagecoating thickness on an article will be greater than the specified value;how much greater is larg

31、ely determined by the shape of the article and thecharacteristics of the deposition process. In addition, the average coatingthickness on articles will vary from article to article within a productionlot. Therefore, if all of the articles in a production lot are to meet thethickness requirement, the

32、 average coating thickness for the production lotas a whole will be greater than the average necessary to ensure that asingle article meets the requirement.5.4 AdhesionThe cadmium-tin coating shall be suffi-ciently adherent to the basis metal to pass the tests specified in8.6.5.5 Corrosion Resistanc

33、e:5.5.1 The presence of corrosion products visible to theunaided eye at normal reading distance at the end of thespecified test period as stated in Table 1 shall constitute failure,except that corrosion products at the edges of specimens shallnot constitute failure. Slight “wisps” of white corrosion

34、, asopposed to obvious accumulations, shall be acceptable.NOTE 3The hours given in Table 1 are the minimums required toguarantee satisfactory performance. Longer periods before the appearanceof white corrosion products and rust are possible, but salt spray resistancedoes not vary in exact proportion

35、 with increased plating thickness. Thehours given for Type II reflect the added protection of chromate treatmentswithout requiring impractical testing periods.B635 00 (2009)25.5.2 There are no requirements for corrosion of base metalsother than steels.NOTE 4Mechanical deposition is exclusively a bar

36、rel-finishing pro-cess. It is recognized that mechanical deposition on parts may thereforeproduce surfaces which have a different characteristic from those on partswhich are finished exclusively by racking. Similarly, corrosion testing ofactual parts may produce different results from those on test

37、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 should indicate his requirementson the purchase order (see 4.1.4).NOTE 5In many instances, there is n

38、o 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 encountered. The results obtained in the te

39、st should not,therefore, be regarded as a direct guide to the corrosion resistance of thetested 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 m

40、aterials inservice.5.6 Absence of Hydrogen Embrittlement Steel springs andother high-strength steel parts subject to flexure shall be heldfor a minimum of 48 h at room temperature after coating,before being loaded, flexed, or used. Such parts shall be freefrom hydrogen embrittlement. When specified

41、in the purchaseorder, freedom from embrittlement shall be determined by thetest specified herein (see 4.1.4 and 8.8).5.7 WorkmanshipThe coating shall be uniform in appear-ance and substantially free of blisters, pits, nodules, flaking andother defects that can adversely affect the function of thecoa

42、ting. The coating shall cover all surfaces as stated in 5.3,including thread roots, thread peaks, corners, recesses, andedges. The coating shall not be stained or discolored through-out to an extent that would adversely affect appearance as afunctional requirement. However, superficial staining that

43、 re-sults from rinsing or drying, and variations in color or lustershall not be cause for rejection.NOTE 6The nature of the mechanical plating process is such thatcoatings characteristically will not be as smooth or as bright as someelectroplated coatings.5.8 Surface DefectsDefects and variations in

44、 appearancein the coating that arise from surface conditions of the substrate(scratches, pores, roll marks, inclusions, etc.) and that persist inthe finish despite the observance of good metal finishingpractices shall not be cause for rejection.NOTE 7Applied finishes generally perform better in serv

45、ice 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 treatments, s

46、uchas 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 (see 4.1.2).6. Sampling6.1 The purchaser and producer are u

47、rged to employ statis-tical process control in the coating process. Properly per-formed, statistical process control will assure coated productsof satisfactory quality and will reduce the amount of accep-tance inspection. The sampling plan used for the inspection ofthe quality coated article shall b

48、e agreed upon between thepurchaser and producer.6.1.1 When a collection of coated articles (inspection lot,see 6.2) is examined for compliance with the requirementsplaced on the articles, a relatively small number of the articles(sample) is selected at random and is inspected. The inspectionlot is t

49、hen classified as complying with the requirements basedon the results of the inspection of the sample. The size of thesample and the criteria for compliance are determined by theapplication of statistics. The procedure is known as samplinginspection. Test Method B602, Guide B697, and Test MethodB762 contain sampling plans that are designed for samplinginspection of coatings.6.1.2 Test Method B602 contains four sampling plans, threefor use with tests that are nondestructive and one when they aredestructive. Test Method B602 provides a default plan if one isnot sp