1、Designation: B 662 94 (Reapproved 2006)Standard Specification forSilver-Molybdenum Electrical Contact Material1This standard is issued under the fixed designation B 662; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、.1.2 This specification covers compositions within the silver-molybdenum system normally specified by users of contacts.1.3 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 become familiarwit
4、h all hazards including those identified in the appropriateMaterial Safety Data Sheet (MSDS) for this product/materialas provided by the manufacturer, to establish appropriatesafety and health practices, and determine the applicability ofregulatory limitations prior to use.2. Referenced Documents2.1
5、 ASTM Standards:2B 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings3. Ordering Information3.1 Orders for this material under this specification shallinclude the following information:3.1.1 Dimensions (see Section 10
6、),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 Section 13), and3.1.5 Other features as agreed upon between the manufac-turer and purchaser.4. Chemical Composition4.1 The materia
7、l 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 prescribed in the newest edition of Volume 01.02of the Annual Book of ASTM Standards or by any otherapproved method agreed upon between
8、 the manufacturer andthe purchaser.5. Physical Properties5.1 The manufacturer and the purchaser shall agree onqualification tests for determination of physical properties.5.2 The tests shall be performed on production parts,wherever practical or applicable. (Small size contacts do notlend themselves
9、 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 ofsilver-molybdenum contacts are given in the appendix.6. Finishing of Contacts6.1 The material shall be finished by such operat
10、ions asnecessary to meet requirements agreed upon between themanufacturer and the purchaser of the contacts (braze alloybacking, tumbling to polish surfaces, special surface finish,silver-rich surface layer, cleaning, etc.).7. Dimensions, Mass and Permissible Variations7.1 Permissible variations in
11、dimensions shall be within thelimits specified on drawings describing the contacts andaccompanying the order; or shall be within the limits specifiedin the purchase order.8. Workmanship, Finish, and Appearance8.1 The parts shall be free of defects in material or process-ing that would seriously affe
12、ct their performance.9. Significance and Use9.1 Proprietary methods for the manufacture of these mate-rials vary significantly among suppliers, and these methodsinfluence such properties as arc erosion, contact resistance, andthe tendency to weld in service. Since the performance ofcontacts in a dev
13、ice 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 the application.As part of the qualification oninitial
14、 samples, it is recommended that the user functionally1This 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 June 1, 2006. P
15、ublished June 2006. Originallyapproved in 1979. Last previous edition approved in 2000 as B 662 94 (2000).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 standa
16、rds Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and electrically test the materials for all devices applicable tothe materials use. This specification will provide a means forthe contact m
17、anufacturer and contact user to reach agreementon the 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 l
18、ot shall consist ofparts of the same form and dimensions, 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.
19、A representative sample of chips may beobtained by milling, 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 B 328 if necessary.10.2.2 These specifica
20、tion limits do not preclude the pos-sible presence of other 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
21、 analysis for specific elements, thenagreement between 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 m
22、icrostructure.11. Inspection11.1 Unless otherwise specified, 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
23、the receipt of shipment.13. Certification13.1 A certification, 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 q
24、uotation and at the time of order placement.14. Keywords14.1 arcing contacts; contacts; electrical contacts; molyb-denum; molybdenum silver; powder metallurgy; silver; silvermolybdenumAPPENDIX(Nonmandatory Information)X1. TYPICAL PROPERTY VALUESX1.1 The following information provides guidelines foru
25、sers and manufacturers of silver-molybdenum contact mate-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 ofmolyb
26、denum, homogeneity, impurities or additives, and othermanufacturing 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
27、as frequency of operation of the device, and how crucial 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
28、are available,care should be taken to ensure that production lots are the samein all respects as samples, and that if a seller change is made,noticeable property or performance variations are possible.B 662 94 (2006)2ASTM International takes no position respecting the validity of any patent rights a
29、sserted in connection with any item mentionedin this standard. 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
30、 by the responsible technical committee and must be reviewed 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 re
31、ceive careful consideration at a meeting of theresponsible 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 In
32、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, 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 thr
33、ough the ASTM website(www.astm.org).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 0.5Cobalt or nickel, max 0.5 0.5 0.5Total impurities, max
34、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 BModulus of rupture:Bpsi 135 000 110 000MPa 931 758Youngs m
35、odulus: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 regularly made for the elements for which specific limits are li
36、sted.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
37、for engineering calculations in contact designbut are not specified.TABLE X1.2 Typical Chemical Ranges Press, Sintered,and Repressed Silver-Molybdenum ContactsComposition,Aweight, %Class A Class BSilver 38 to 42 48 to 52Molybdenum balance balanceNickel, cobalt, or copper, max 0.5 0.5Total impurities
38、, 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 8300MPa 68 57Theoretical density, min, % 95 95AAnalysis is r
39、egularly 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.B 662 94 (2006)3
