ASTM_B_780_-_16.pdf

Designation:B78016Standard Specification for75%Silver,24.5%Copper,0.5%Nickel Electrical ContactAlloy1This standard is issued under the fixed designation B780;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript 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 an electrical contact materialwith the nominal composition of 75%silver,24.5%copper,and 0.5%nickel in the form of rod,wire,strip,and sheet.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.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 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:2B476 Specification for General Requirements for WroughtPrecious Metal Electrical Contact Materials3.Ordering Information3.1 Refer to Specification B476.4.Materials and Manufacture4.1 Raw materials shall be of such quality and purity thatthe finished product will have the properties and characteristicsprescribed in this specification.4.2 The material shall be finished by such operations(coldworking,heat-treating,annealing,turning,grinding,or pick-ling)as are required to produce the prescribed properties.5.Chemical Composition5.1 Material produced under this specification shall conformto the chemical composition limits prescribed in Table 1.5.2 These specification limits do not preclude the possiblepresence of other unnamed elements,impurities,or additives.Analysis shall be regularly made only for the minor elementslisted in the table.However,if a user knows of elements thatmight be detrimental to their application or has other reasonsfor requiring analysis for specific elements,then agreementbetween manufacturer and purchaser for both limits andmethods of analysis should be required for elements notspecified.6.Mechanical Properties6.1 The material shall conform to the applicable mechanicalproperties prescribed in Table 2 or Table 3.6.2 All test specimens shall be the full thickness or diameteras the size supplied when practical.The test procedures shallfollow the ASTM specifications referred to in SpecificationB476.6.3 All tests are to be conducted at room temperature,about68F(20C).7.Inspection,Rejection and Rehearing,Certification,Product Marking,and Supplementary Requirements7.1 Material furnished to this specification shall meet therequirements listed in Specification B476.8.Keywords8.1 arcing contacts;contacts;conductivity;electrical con-tacts;precious metals;silver alloy;silver-copper alloy;wire1This 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 1987.Last previous edition approved in 2010 as B780 98(2010).DOI:10.1520/B0780-16.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 APPENDIX(Nonmandatory Information)X1.Typical Property ValuesX1.1 Electrical Conductivity:TemperAnnealed14Hard12HardHardExtraHardSpringExtraSpringB and S No.01246810ElectricalConductivity IACS,percent76747473727070MS/m44.142.942.942.341.840.640.6TABLE 1 Chemical CompositionNOTE1Analysis is regularly made for the elements for which specificlimits are listed.If however,the presence of“other”elements is suspectedor indicated in the course of routine analysis,further analysis shall bemade to determine that the total of these“other”elements and the listedimpurities is not in excess of the total impurities limit.NOTE2Refer to 5.2.ElementWeight,%Silver74.076.0Copper(23.5 min)report by differenceNickel0.350.65ImpuritiesZinc0.06 maxIron0.05 maxCadmium0.01 maxLead0.03 maxTotal of all impurities0.15 maxTABLE 2 Mechanical Properties of Wire and RodAreaReduction,%TemperDesignationB andS No.Tensile Strength%Elonga-tion in2 in.(51mm),minksiMPa0annealed04055280380101118hard506235043052114hard1586840047043712hard26474440510460hard47080480550284spring880925