1、Designation: B 780 98 (Reapproved 2004)Standard Specification for75 % Silver, 24.5 % Copper, 0.5 % Nickel Electrical ContactAlloy1This standard is issued under the fixed designation B 780; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specification
3、 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 This standard does not purport to address all the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of t
4、his standard to become familiar with all hazardsincluding those identified in the appropriate Material SafetyData Sheet for this product/material as provided by themanufacturer, to establish appropriate safety and health prac-tices, and determine the applicability of regulatory limitationsprior to u
5、se.2. Referenced Documents2.1 ASTM Standards:2B 476 Specification for General Requirements for WroughtPrecious Metal Electrical Contact Materials3. Ordering Information3.1 Refer to Specification B 476.4. Materials and Manufacture4.1 Raw materials shall be of such quality and purity thatthe finished
6、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
7、 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 t
8、able. 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. Mechanica
9、l 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 SpecificationB
10、476.6.3 All tests are to be conducted at room temperature, about68F (20C).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 appr
11、oved May 1, 2004. Published May 2004. Originallyapproved in 1987. Last previous edition approved in 1998 as B 780 98.2For 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
12、 the standards Document Summary page onthe ASTM website.TABLE 1 Chemical CompositionNOTE 1Analysis 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 b
13、emade to determine that the total of these “other” elements and the listedimpurities is not in excess of the total impurities limit.NOTE 2Refer to 5.2.Element Weight,%Silver 74.076.0Copper (23.5 min) report by differenceNickel 0.350.65ImpuritiesZinc 0.06 maxIron 0.05 maxCadmium 0.05 maxLead 0.03 max
14、Total of all impurities 0.15 max1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Inspection, Rejection and Rehearing, Certification,Product Marking, and Supplementary Requirements7.1 Material furnished to this specification shall m
15、eet therequirements listed in Specification B 476.8. Keywords8.1 arcing contacts; contacts; conductivity; electrical con-tacts; precious metals; silver alloy; silver-copper alloy; wireAPPENDIX(Nonmandatory Information)X1. Typical Property ValuesX1.1 Electrical Conductivity:Temper An-nealed14Hard12Ha
16、rdHard ExtraHardSpring ExtraSpringBandSNo. 01246810Electrical Conduc-tivity IACS,percent76 74 74 73 72 70 70MS/m 44.1 42.9 42.9 42.3 41.8 40.6 40.6X1.2 Density:Nominal 10.04 Mg/m3(5.29 troy oz/in.3)X1.3 Linear Coeffcient of Expansion:9.90 3 106in./in.-F17.82 3 106m/mCX1.4 Modulus of Elasticity:12.3
17、3 106psi (84.8 GPa)X1.5 Typical Mechanical Properties (Spring Temper.010inch diameter wire)(a.) Fatigue strength (Rotating Bending) at 108cycles40,000 psi (280 MPa)(b.) Proportional limit 65,000 psi (455 MPa)(c.) Microhardness 160 HK 100gASTM International takes no position respecting the validity o
18、f any patent rights asserted 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
19、 revision at any time 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.
20、Your comments will receive 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 c
21、opyrighted by ASTM International, 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
22、.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Mechanical Properties of Wire and RodArea Re-duction,%TemperDesignationB andS No.Tensile Strength % Elonga-tion in2 in. (51mm), minksi MPa0 annealed 0 4055 280380 101118 hard 5062 350430 52114 hard 1 5868 400470 43712 hard 2 6474 44051
23、0 460 hard 4 7080 480550 284 spring 8 8092 550630 1TABLE 3 Mechanical Properties of Sheet and StripThicknessReduction,%TemperDesig-nationB and SNo.Tensile Strength Elonga-tion%in 2 in.(51 mm),minHardnessRockwell30Tksi MPaannealed annealed 0 4557 310390 8 46581114 hard 1 5062 340430 4 56622112 hard 2 5567 370450 3 606637 hard 4 6375 430520 2 6470B 780 98 (2004)2
