1、Designation: B692 90 (Reapproved 2012)B692 18Standard Specification for75 % Silver-25 % Graphite Sliding Contact Material1This standard is issued under the fixed designation B692; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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.1. Scope1.1 This specification defines the criteria for composition and other requirements for brushes with a nominal sil
3、ver content of75 weight % with the balance being substantially graphite.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.3 This st
4、andard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety DataSheet (MSDS)(SDS) for this product/material as pr
5、ovided by the manufacturer, to establish appropriate safety safety, health, andhealthenvironmental practices, and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizati
6、onestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B613 Guide for Preparing Specifications for Miniature Br
7、ushes of Composite Materials for Sliding Electric ContactsE18 Test Methods for Rockwell Hardness of Metallic Materials2.2 ANSINEMA Standard:C64.1CB-1 Brushes for Electrical Machines33. Requirements3.1 Chemical Composition shall be as follows:Silver 75 3 % (weight)Graphite balanceTotal metal impuriti
8、es 1 % maxPercent ash in graphite (ANSI C64.1) 5 % maxPercent ash in graphite (NEMA CB-1) 5 % max3.2 Physical PropertiesThe following lot average properties must be met. Unless otherwise agreed between the producer andthe user, the number of samples shall be five.3.2.1 DensityThe minimum acceptable
9、density shall be 4.6 g/cm 3 as determined by the measurement and weight methoddefined by ANSI C64.1.NEMA CB-1.3.2.2 Shear Strength:3.2.2.1 The shear strength for the normal and transverse directions shall be measured for rectangular parallelepipeds and shallbe 2000 psi (14 MPa), minimum.3.2.2.2 The
10、shear strength for the longitudinal shear direction shall be measured for cylinders and shall be 1000 psi (6.9 MPa),minimum.1 This specification is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.05 onPrecious Metals a
11、nd Electrical Contact Materials.Current edition approved May 1, 2012Nov. 1, 2018. Published May 2012January 2019. Originally approved in 1981. Last previous edition approved in 20062012 asB692 90 (2006).(2012). DOI: 10.1520/B0692-90R12.10.1520/B0692-18.2 For referencedASTM standards, visit theASTM w
12、ebsite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave.
13、 Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.National Electrical Manufacturers Association (NEMA), 1300 N. 17th St., Suite 1752, Rosslyn, VA 22209, http:/www.nema.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what
14、changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the o
15、fficial document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3 MicrostructureParts shall be visually free of structural defects, cracks, etc., upon examination at 50. The press direction,as evidenced by laminations, shall be as
16、defined by the purchase order. Also the brush material shall not contain abrasive particlesthat will sliver a metal-alloy ring with a hardness 110 HK100 when the brush force is equal to 30 g or that necessary for 5.0 psi(34 kPa) pressure, whichever is greater. A sliver is defined as a loose wear par
17、ticle with one dimension 50 the next smallerdimension. Although slivering can be caused by coarse abrasive particles, other parameters can contribute to slivering (forexample, very high brush force).3.4 Source or Grade of Raw Materials (for example, graphite) or methods of manufacture shall not be c
18、hanged withoutnotifying users.4. Reference Properties4.1 Because of their size, the following properties can not always be determined. However, these properties are typical for largerparts.4.1.1 Superficial HardnessThe typical superficial hardness for this material is Rockwell 15W50 as determined by
19、 TestMethods E18 with a 18-in. (3.2-mm) steel ball.4.1.2 Specific ResistanceThe typical specific resistance for the material is 6 106 -in. (1.5 107 -m) as determinedby the method detailed in ANSI C64.1. NEMA CB-1.5. Certification5.1 Material supplied under this specification shall be certified as me
20、eting the requirements of this specification by the producerof the material.6. Keywords6.1 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
21、 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 revision at any time by the responsible technical committee and must be reviewed every five
22、 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. Your comments will receive careful consideration at a meeting of theresponsible technical com
23、mittee, 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 copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
24、9428-2959,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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 182
