1、Designation: B635 00 (Reapproved 2015)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 ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby 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 Test
8、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 ChemicalAnalysis of Lead,Tin,Antimony,and
9、 Their Alloys (Photometric Methods) (Withdrawn1983)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
10、Inspection, Sampling and Testing42.3 U.S. Military Standard:MIL-L-7808J Lubricating Oil,AircraftTurbine Engine, Syn-thetic Base43. Classification3.1 ClassesCadmium-tin coatings are classified on thebasis of thickness, as follows:Class Minimum Thickness, m12 1288553.2 TypesCadmium-tin coatings are id
11、entified 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 onMetallic and Inor
12、ganic Coatings and is the direct responsibility of SubcommitteeB08.06 on Soft Metals.Current edition approved March 1, 2015. Published April 2015. Originallyapproved in 1978. Last previous edition approved in 2009 as B635 00(2009). DOI:10.1520/B0635-00R15.2For referenced ASTM standards, visit the AS
13、TM 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 website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from Stand
14、ardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Ordering Information4.1 To make the application of this specification com
15、plete,the purchaser needs to supply the following information to thesupplier in the purchase order or other 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-stre
16、ngth steel,need for stress-relief, and cleaning precautions to be followed(5.2.2).4.1.3 Significant surfaces (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
17、absence of hydrogen embrittlement and the waitingperiod prior to testing and testing loads (8.8) and lubricatingresistance (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 cert
18、ified report of test results (Sec-tion 10).5. Requirements5.1 Nature of FinishThe coating shall be 45 to 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 ma
19、chining, grinding,straightening, or cold forming operation shall be given a stressrelief heat treatment prior 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 s
20、pecified minimum.5.2.2 High-strength steels that have heavy oxide or scaleshall be cleaned before application 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 emb
21、rittlement from thecleaning procedure.5.2.3 For preparation of low-carbon steels, see PracticeB183. For cleaning, 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 soluti
22、on shallproduce a bright or semi-bright continuous, smooth, protectivefilm. This film may have a slight yellowish 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
23、 that yield films contain-ing hexavalent chromium are permitted as treatments forproducing Type II coatings.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 suppl
24、emental lubrication treatments shall not beused to ensure conformance to the salt spray corrosion resistantrequirements 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
25、 the specified classas defined in 3.1.5.3.2 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 which can be the source of corrosionproducts that deface visible
26、 surfaces on the assembled article.When necessary, the significant surfaces shall be indicated onthe drawing 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
27、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 requirement.5.3.3 When significant surfaces are involved on which thespecified thickness of deposit
28、 cannot readily be controlled, thepurchaser and manufacturer should recognize the necessity foreither thicker 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
29、 be reduced proportionately.NOTE 2The 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 to point on a c
30、oated articleis an inherent characteristic of mechanical deposition processes.Therefore, the coating thickness will have to exceed the specified value atsome points on the significant surfaces to ensure that the thickness equalsor exceeds the specified value at all points. Thus, in most cases, theav
31、erage coating thickness on an article will be greater than the specifiedvalue; how much greater is largely determined by the shape of the articleand the characteristics of the deposition process. In addition, the averagecoating thickness on articles will vary from article to article within aproducti
32、on lot. Therefore, if all of the articles in a production lot are tomeet the thickness requirement, the average coating thickness for theproduction lot as a whole will be greater than the average necessary toensure that a single article meets the requirement.5.4 AdhesionThe cadmium-tin coating shall
33、 be suffi-ciently adherent to the basis metal to pass the tests specified in8.6.5.5 Corrosion Resistance: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 corr
34、osion products at the edges of specimens shallnot constitute failure. Slight “wisps” of white corrosion, 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 whi
35、te corrosion products and rust are possible, but salt spray resistancedoes not vary in exact proportion with increased plating thickness. Thehours given for Type II reflect the added protection of chromate treatmentswithout requiring impractical testing periods.B635 00 (2015)25.5.2 There are no requ
36、irements for corrosion of base metalsother than steels.NOTE 4Mechanical deposition is exclusively a barrel-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
37、 racking. Similarly, corrosion testing ofactual parts may produce different results from those 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 purchase
38、r should indicate his requirementson the purchase order (see 4.1.4).NOTE 5In 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 for
39、mation 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 thetested materials in all environments where these materials may be used.Also, performance of different materi
40、als in the test cannot always be takenas a direct guide to the relative corrosion resistance of these materials 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,bef
41、ore being loaded, flexed, or used. Such parts shall be freefrom hydrogen embrittlement. When specified 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 fre
42、e of blisters, pits, nodules, flaking andother defects that can adversely affect the function of thecoating. 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 exten
43、t that would adversely affect appearance as afunctional requirement. However, superficial staining that 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 n
44、ot be as smooth or as bright as someelectroplated coatings.5.8 Surface DefectsDefects and variations in 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 fini
45、shingpractices shall not be cause for rejection.NOTE 7Applied 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 p
46、rovide limits for these defects.Ametal 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 stepspreceding the application of the finish. When desired, t
47、hey must bespecified on the purchase order (see 4.1.2).6. Sampling6.1 The purchaser and producer are urged to employ statis-tical process control in the coating process. Properlyperformed, statistical process control will assure coated prod-ucts of satisfactory quality and will reduce the amount ofa
48、cceptance inspection. The sampling plan used for the inspec-tion of the quality coated article shall be agreed upon betweenthe purchaser 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 relative
49、ly small number of the articles(sample) is selected at random and is inspected. The inspectionlot is then 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 nond
