1、Designation: B 702 93 (Reapproved 2004)Standard Specification forCopper-Tungsten Electrical Contact Material1This standard is issued under the fixed designation B 702; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers electrical contact componentsmade from copper tungsten by powder metallurgical proce-dures.1.2
3、 This specification covers compositions within the cop-per tungsten 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 familiarwith all
4、 hazards including those identified in the appropriateMaterial Data Safety Sheet for this product/material as pro-vided by the manufacturer, to establish appropriate safety andhealth practices, and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Stan
5、dards:2B 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings3. Significance and Use3.1 Proprietary methods for manufacture of these materialsvary significantly among suppliers and these methods influencesuch properties
6、 as arc erosion, contact resistance, and tendencyto weld in service. Since the performance of contacts in adevice depends on numerous factors outside the contact itself(opening speed, closing speed, contact pressure, contactbounce, environmental variations, assembly technique andvariations, etc.) th
7、is specification cannot ensure performancecontrol in the application. As part of the qualification on initialsamples it is recommended that the user functionally electri-cally test the materials for all devices applicable to thematerials use. This specification will provide a means for thecontact ma
8、nufacturer and contact user to reach agreement onthe details of material to be supplied for a specified use andreasonable assurance that future lots will be similar in proper-ties and microstructure to the initial test or sample contactssupplied.4. Ordering Information4.1 Orders for this material un
9、der this specification shallinclude the following information:4.1.1 Dimensions (see Section 8),4.1.2 Chemical composition (see reference tables in RelatedMaterial as possible guideline),4.1.3 Physical properties (see Section 6 and reference tablesas guideline),4.1.4 Certification (see Section 11), a
10、nd4.1.5 Other features as agreed upon between the vendor andthe user.5. Chemical Requirements5.1 The material shall conform to composition limits asagreed upon between the manufacturer and the user.5.2 The chemical analysis shall be made in accordance withthe methods prescribed in the newest edition
11、 of Annual Book ofASTM Standards, or by any other approved method agreedupon between the manufacturer and the purchaser.6. Other Properties6.1 The manufacturer and the purchaser shall agree onqualification tests for determination of physical properties.6.2 The tests shall be performed on production
12、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 five most common types ofcopper-tungsten contacts are given in Appen
13、dix X1.7. Dimensions 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.1This specification is under the jurisdiction of AST
14、M 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, 2004. Published May 2004. Originallyapproved in 1982. Last previous edition approved in 1993 as B 702 93 (1998).2F
15、or 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C7
16、00, West Conshohocken, PA 19428-2959, United States.8. Workmanship, Finish, and Appearance8.1 The parts shall be free of defects in material or process-ing, which would seriously affect their performance.9. Sampling and Inspection9.1 LotUnless otherwise specified, a lot shall consist ofparts of the
17、same form, and dimensions, made of powders ofthe same particle size range and composition, processed underthe same conditions, and submitted for inspection at one time.9.2 Chemical AnalysisAt least one sample for chemicalanalysis shall be taken from each lot. A representative sampleof chips may be o
18、btained by milling, drilling, or crushing atleast two pieces with dry tools, without lubrication. In order toobtain oil-free chips, the parts selected for test shall have theoil extracted in accordance with Method B 328, if necessary.9.2.1 These specification limits do not preclude the possibleprese
19、nce 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 agreementb
20、etween manufacturer and purchaser for both limits andmethods of analysis should be required for elements notspecified.9.3 Physical TestsThe manufacturer and the purchasershall agree on a representative number of specimens forphysical tests including microstructure.10. Rejection and Rehearing10.1 Unl
21、ess otherwise specified, rejections based on testsmade in accordance with the specification shall be reported tothe manufacturer within 30 days of the receipt of shipment.11. Certification11.1 A certification, when requested by the user, based onthe manufacturers quality control, that the material c
22、onformsto the 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.12. Keywords12.1 contacts; copper; coppertungsten; powder metallurgy;tungsten; tungstencopperAPPENDIX(Nonmand
23、atory Information)X1. TYPICAL PROPERTY VALUESX1.1 ScopeX1.1.1 The following information provides guidelines forusers and manufacturers of copper-tungsten contact material.Typical ranges of chemistry and properties are given for therange of compositions available. Some manufacturers offerspecific com
24、positions other than those listed. Properties areinfluenced by the particle size, shape, and distribution of thetungsten as well as by the presence of additives or othermanufacturing process variables. The best choice for a givenapplication should be mutually decided between the purchaserand the sup
25、plier using their mutual experience and applicationengineering knowledge.X1.1.2 With the knowledge that several types of materialare available, care should be taken to ensure that productionlots are the same in all respects as samples and that if a vendorchange is made, noticeable property or perfor
26、mance variablesare possible. See Table X1.1 X1.1.B 702 93 (2004)2ASTM International takes no position respecting the validity of 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 su
27、ch 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 reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invit
28、ed 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 theresponsible technical committee, which you may attend. If you feel that your comments have not received a
29、 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 Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this
30、 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).TABLE X1.1 Chemical RequirementsAClass A Class B Class C Class D Class ECopper, % 4852 3842 2832 2327 1822Tungsten,
31、% balance balance balance balance balanceAdditives (Individual or total), max,% 1.00 1.00 1.00 1.00 1.00Physical PropertiesBClass A Class B Class C Class D Class EHardness, Rockwell B 6983 7790 8598 89102 94106Density, Mg/m3at 96 % theoretical 11.7 12.7 13.7 14.3 15.0Electrical conductivity,C% IACS
32、5664 4957 4452 4148 3845Electrical conductivity,D% IACS 3856 3449 2943 2741 2537NoteHardness and density values cover both types.Physical PropertiesEClass A Class B Class C Class D Class ETensile Strength, ksi MPa 506034441355653794487585516585859558565490100620689Modulus of Rupture, ksi MPa 7585517
33、586110120758827130140896965140150965103415016010341103Coefficient of Expansion, in./in.F m/mK7.2 3 10613 3 1066.6 3 10611.9 3 1065.7 3 10610.3 3 1065.3 3 1069.5 3 1064.9 3 1068.8 3 106AAnalysis is regularly made for the elements for which specific limits are listed. If, however, the presence of“ oth
34、er” elements is suspected or indicated in the course ofroutine analysis, further analysis shall be made to determine that the total of these “other” elements and the listed impurities are not in excess of the total impurities limit.BThese data do not constitute a part of the specifications. They ind
35、icate to the purchaser the properties that may be expected from a given particle size of powder. Thevalues will vary to some degree with the size of part, configuration of part, composition, and microstructure. Certain specific applications may require modification of thesebasic materials. In such case, the properties required are determined by agreement between the purchaser and the supplier.CTypical values for infiltrated type.DTypical values for liquid phase sintered type.EItems that are normally useful for engineering calculations in contact design but are not specified.B 702 93 (2004)3
