1、Designation: B662 94 (Reapproved 2012)Standard Specification forSilver-Molybdenum Electrical Contact Material1This standard is issued under the fixed designation B662; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 electrical contact componentsmade from silver-molybdenum by powder metallurgical pro-cedures.1.
3、2 This specification covers compositions within the silver-molybdenum system normally specified by users of contacts.1.3 The values stated in inch-pound units are to be regardedas standard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all o
4、f thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet (MSDS) for this product/materialas provided by the manufacturer, to establish appropr
5、iatesafety and health practices, and determine the applicability ofregulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings33. Ordering Informa
6、tion3.1 Orders for this material under this specification shallinclude the following information:3.1.1 Dimensions (see Section 10),3.1.2 Chemical composition (see tables in the appendix as aguideline),3.1.3 Physical properties (see Section 5 and the appendix asa guideline),3.1.4 Certification (see S
7、ection 13), and3.1.5 Other features as agreed upon between the manufac-turer and purchaser.4. Chemical Composition4.1 The material shall conform to composition limits asagreed upon between the manufacturer and the purchaser.4.2 The chemical analysis shall be made in accordance withthe methods prescr
8、ibed in the newest edition of Volume 01.02of the Annual Book of ASTM Standards or by any otherapproved method agreed upon between the manufacturer andthe purchaser.5. Physical Properties5.1 The manufacturer and the purchaser shall agree onqualification tests for determination of physical properties.
9、5.2 The tests shall be performed on production parts,wherever practical or applicable. (Small size contacts do notlend themselves to accurate conductivity measurement.)5.3 The tests shall be determined after consideration of thefunction of the part.5.4 The typical properties of two most common types
10、 ofsilver-molybdenum contacts are given in the appendix.6. Finishing of Contacts6.1 The material shall be finished by such operations asnecessary to meet requirements agreed upon between themanufacturer and the purchaser of the contacts (braze alloybacking, tumbling to polish surfaces, special surfa
11、ce finish,silver-rich surface layer, cleaning, etc.).7. Dimensions, Mass, and Permissible Variations7.1 Permissible variations in dimensions shall be within thelimits specified on drawings describing the contacts andaccompanying the order; or shall be within the limits specifiedin the purchase order
12、.8. Workmanship, Finish and Appearance8.1 The parts shall be free of defects in material or process-ing that would seriously affect their performance.9. Significance and Use9.1 Proprietary methods for the manufacture of these mate-rials vary significantly among suppliers, and these methodsinfluence
13、such properties as arc erosion, contact resistance, and1This specification is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.05 on Precious Metals and Electrical Contact Materials.Current edition approved May 1, 2012. P
14、ublished May 2012. Originallyapproved in 1979. Last previous edition approved in 2006 as B662 94 (2006).DOI: 10.1520/B0662-94R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
15、on, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the tendency to weld i
16、n service. Since the performance ofcontacts in a device depends on numerous factors outside thecontact itself (opening speed, closing speed, contact pressure,contact bounce, environmental variations, assembly techniqueand variations, etc.), this specification cannot ensure perfor-mance control in th
17、e application.As part of the qualification oninitial samples, it is recommended that the user functionallyand electrically test the materials for all devices applicable tothe materials use. This specification will provide a means forthe contact manufacturer and contact user to reach agreementon the
18、details of the material to be supplied for a specific use,and reasonable assurance that future lots will be similar inproperties and microstructure to the initial test or samplecontacts supplied.10. Sampling10.1 LotUnless otherwise specified, a lot shall consist ofparts of the same form and dimensio
19、ns, made of powders of thesame particle size range and composition, processed under thesame conditions, and submitted for inspection at one time.10.2 Chemical Analysis:10.2.1 At least one sample for chemical analysis shall betaken from each lot. A representative sample of chips may beobtained by mil
20、ling, drilling, or crushing at least two pieceswith dry tools, without lubrication. In order to obtain oil-freechips, the parts selected for test shall have the oil extracted inaccordance with Test Method B328 if necessary.10.2.2 These specification limits do not preclude the pos-sible presence of o
21、ther unnamed elements, impurities, oradditives. Analysis shall be regularly made only for the minorelements listed in the table. However, if a user knows ofelements that might be detrimental to their application or hasother reasons for requiring analysis for specific elements, thenagreement between
22、manufacturer and purchaser for both limitsand methods of analysis should be required for elements notspecified.10.3 Physical TestsThe manufacturer and the purchasershall agree on a representative number of specimens forphysical tests including microstructure.11. Inspection11.1 Unless otherwise speci
23、fied, inspection of parts suppliedon contract shall be made by the purchaser.12. Rejection12.1 Unless otherwise specified, rejections based on testsmade in accordance with the specification shall be reported tothe manufacturer within 30 days of the receipt of shipment.13. Certification13.1 A certifi
24、cation, when requested by the user, based onthe manufacturers quality control that the material conforms tothe requirements of this specification, shall be furnished uponrequest of the purchaser, provided the request is made at thetime of cost quotation and at the time of order placement.14. Keyword
25、s14.1 arcing contacts; contacts; electrical contacts; molybde-num; molybdenum silver; powder metallurgy; silver; silvermolybdenumAPPENDIX(Nonmandatory Information)X1. TYPICAL PROPERTY VALUESX1.1 The following information provides guidelines forusers and manufacturers of silver-molybdenum contact mat
26、e-rial. Typical ranges of chemistry and properties are given forthe two most popular compositions, 40 % silver/60 % molyb-denum and 50 % silver/50 % molybdenum. These propertiesare influenced by the particle size, shape, and distribution ofmolybdenum, homogeneity, impurities or additives, and otherm
27、anufacturing process variables.NOTE X1.1Table X1.1 and Table X1.2 represent the major manufac-turing techniques used in industry. The size and shape of the part isimportant in choosing the optimum technique as well as other consider-ations such as frequency of operation of the device, and how crucia
28、l is itsapplication.X1.1.1 The best choice for a given application should bemutually decided between the purchaser and the manufacturerusing their mutual experience and application engineeringknowledge.X1.2 With the knowledge that several types are available,care should be taken to ensure that produ
29、ction lots are the samein all respects as samples, and that if a seller change is made,noticeable property or performance variations are possible.B662 94 (2012)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this sta
30、ndard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be revi
31、ewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsib
32、le technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
33、nshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights t
34、o photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE X1.1 Typical Chemical Ranges Infiltrated Silver-Molybdenum ContactsComposition,Aweight, %Class A1 Class A Class BSilver 33 to 37 38 to 42 48 to 52Molybdenum balance balance balanceCopper, max 0.5 0.5 0
35、.5Cobalt or nickel, max 0.5 0.5 0.5Total impurities, max 1 1 1Typical PropertiesClass A1 Class A Class BHardness, Rockwell B 80 to 100 72 to 92 60 to 85Density, Mg/m310.3 10.3 10.3Electrical conductivity, % IACS 35 to 45 45 to 50 50 to 55Theoretical density, min, % 96 96 96PropertiesClass A Class BM
36、odulus of rupture:Bpsi 135 000 110 000MPa 931 758Youngs modulus:Bpsi 36.4 3 10632 3 106GPa 250 220Tensile strength:Bpsi 55 000 45 000MPa 379 310Coefficient of expansion:Bin./in.F 7.75 3 1066.9 3 106m/mK 13.95 3 10612.4 3 106Thermal conductivity:BBtuin./hft2F 2664 2988W/mK 384 431AAnalysis is regular
37、ly made for the elements for which specific limits are listed.If, however, the presence of “other” elements is suspected or indicated in thecourse of routine analysis, further analysis shall be made to determine that thetotal of these “other” elements and the listed impurities are not in excess of t
38、he totalimpurities limit.BItems that are normally useful for engineering calculations in contact designbut are not specified.TABLE X1.2 Typical Chemical Ranges Press, Sintered, andRepressed Silver-Molybdenum ContactsComposition,Aweight, %Class A Class BSilver 38 to 42 48 to 52Molybdenum balance bala
39、nceNickel, cobalt, or copper, max 0.5 0.5Total impurities, max 1 1Typical PropertiesClass A Class BRockwell B: 60 to 75 60 to 75Hardness of repressed part 50 to 70 40 to 70Hardness after annealing 10.3 10.3Density, Mg/m340 to 50 45 to 55Electrical conductivity, % IACSModulus of rupture:Bpsi 9800 830
40、0MPa 68 57Theoretical density, min, % 95 95AAnalysis is regularly made for the elements for which specific limits are listed.If, however, the presence of “other” elements is suspected or indicated in thecourse of routine analysis, further analysis shall be made to determine that thetotal of these “other” elements and the listed impurities are not in excess of the totalimpurities limit.BItems that are normally useful for engineering calculations in contact designbut not specified.B662 94 (2012)3
