1、Designation: B 692 90 (Reapproved 2006)Standard Specification for75 % Silver-25 % Graphite Sliding Contact Material1This standard is issued under the fixed designation B 692; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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.1. Scope1.1 This specification defines the criteria for compositionand other requirements for brushes with a nominal silverco
3、ntent of 75 weight % with the balance being substantiallygraphite.1.2 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 approp
4、riateMaterial 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 ASTM Standards:2B 613 Guide for Preparing Specificati
5、ons for MiniatureBrushes of Composite Materials for Sliding Electric Con-tactsE18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic Materials2.2 ANSI Standard:C64.1 Brushes for Electrical Machines33. Requirements3.1 Chemical Composition shall be as follows:Silver 75 6 3
6、 % (weight)Graphite balanceTotal metal impurities 1 % maxPercent ash in graphite (ANSI C64.1) 5 % max3.2 Physical PropertiesThe following lot average proper-ties must be met. Unless otherwise agreed between the pro-ducer and the user, the number of samples shall be five.3.2.1 DensityThe minimum acce
7、ptable density shall be4.6 g/cm3as determined by the measurement and weightmethod defined by ANSI C64.1.3.2.2 Shear Strength:3.2.2.1 The shear strength for the normal and transversedirections shall be measured for rectangular parallelepipedsand shall be 2000 psi (14 MPa), minimum.3.2.2.2 The shear s
8、trength for the longitudinal shear direc-tion shall be measured for cylinders and shall be 1000 psi (6.9MPa), minimum.3.3 MicrostructureParts shall be visually free of structuraldefects, cracks, etc., upon examination at 503. The pressdirection, as evidenced by laminations, shall be as defined bythe
9、 purchase order. Also the brush material shall not containabrasive particles that will sliver a metal-alloy ring with ahardness$110 HK10 0when the brush force is equal to 30 g orthat necessary for 5.0 psi (34 kPa) pressure, whichever isgreater. A sliver is defined as a loose wear particle with onedi
10、mension $503 the next smaller dimension. Although sliv-ering can be caused by coarse abrasive particles, other param-eters can contribute to slivering (for example, very high brushforce).3.4 Source or Grade of Raw Materials (for example, graph-ite) or methods of manufacture shall not be changed with
11、outnotifying users.4. Reference Properties4.1 Because of their size, the following properties can notalways be determined. However, these properties are typicalfor larger parts.4.1.1 Superficial HardnessThe typical superficial hard-ness for this material is Rockwell 15W50 as determined byTest Method
12、s E18with a18-in. (3.2-mm) steel ball.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 June 1, 2006. Published June 20
13、06. Originallyapproved in 1981. Last previous edition approved in 2000 as B 692 90 (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 standards Document Sum
14、mary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.2 Specific ResistanceThe
15、typical specific resistancefor the material is 6 3 106V-in. (1.5 3 107V-m) asdetermined by the method detailed in ANSI C64.1.5. Certification5.1 Material supplied under this specification shall be cer-tified as meeting the requirements of this specification by theproducer of the material.6. Keywords
16、6.1 electrical contacts; graphite; silver; sliding contactsASTM 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 such pat
17、ent 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 invited eit
18、her 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 fair
19、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 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).B 692 90 (2006)2
