ASTM_B_663_-_B_663M_-_16.pdf

Designation:B663/B663M16Standard Specification forSilver-Tungsten Carbide Electrical Contact Material1This standard is issued under the fixed designation B663/B663M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers electrical contact componentsmade from silver-tungsten carbide materials by powder metal-lurgical processes.1.2 This specification covers compositions within the silver-tungsten carbide system normally specified by users of con-tacts.NOTE1Table X1.1 and Table X1.2 in Appendix X1 provide a list oftypical compositions used for various applications.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.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 become familiarwith all hazards including those identified in the appropriateSafety Data Sheet(SDS)for this product/material as providedby the manufacturer,to establish appropriate safety and healthpractices,and determine the applicability of regulatory limi-tations 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for Density,Oil Content,and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings(Withdrawn 2009)33.Significance and Use3.1 Proprietary methods for the manufacture of these mate-rials vary significantly among suppliers,and these methodsinfluence such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 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 the 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 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.4.Ordering Information4.1 Orders for this material under this specification shallinclude the following information:4.1.1 Dimensions(see Section 10),4.1.2 Chemical composition(see Table X1.1 and Table X1.2in Appendix X1 as a guideline),4.1.3 Physical properties(see Section 6 and Appendix X1 asa guideline),4.1.4 Certification(see Section 13),and4.1.5 Other features as agreed upon between the manufac-turer and purchaser.5.Chemical Composition5.1 The material shall conform to composition limits asagreed upon between the manufacturer and the purchaser.5.2 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 the manufacturer andthe purchaser.6.Physical Properties6.1 The manufacturer and the purchaser shall agree onqualification tests for determination of physical properties.1This 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 1,2016.Published May 2016.Originallyapproved in 1979.Last previous edition approved in 2012 as B663 94(2012).DOI:10.1520/B0663/B0663M-16.2For 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 website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 The tests shall be performed on production parts,wherever practical or applicable.(Small size contacts do notlend themselves to accurate conductivity measurement.)6.3 The tests shall be determined after consideration of thefunction of the part.6.4 The typical properties of three most common types ofsilver-tungsten carbide contacts are given in Appendix X1.7.Dimensions,Mass,and Permissible