1、Designation: C 783 85 (Reapproved 2005)An American National StandardStandard Practice forCore Sampling of Graphite Electrodes1This standard is issued under the fixed designation C 783; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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.1. Scope1.1 This practice was developed for electric-arc furnacegraphite electrodes, and covers a procedure and equ
3、ipment forobtaining core samples from electrodes in a manner that doesnot destroy the electrode nor prevent its subsequent use asoriginally intended. However, the minimum electrode diam-eter, for which extraction of a core sample using this practicedoes not influence subsequent use, is influenced by
4、 the par-ticular application and must be determined by the user.Graphite electrodes for use in electric arc furnaces are usuallysolid cylinders of graphite with threaded sockets machined ineach end.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its u
5、se. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1The followingASTM standards are noted as sources of usefulinformation: Test Methods C 559, C611, C 651, C 747,
6、C 1025, andC 1039.2. Referenced Documents2.1 ASTM Standards:2C 559 Test Method for Bulk Density by Physical Measure-ment of Manufactured Carbon and Graphite ArticlesC611 Test Method for Electrical Resistivity of Manufac-tured Carbon and Graphite Articles at Room TemperatureC 651 Test Method for Flex
7、ural Strength of ManufacturedCarbon and Graphite Articles Using Four-Point Loading atRoom TemperatureC 747 Test Method for Moduli of Elasticity and Fundamen-tal Frequencies of Carbon and Graphite Materials by SonicResonanceC 1025 Test Method for Modulus of Rupture in Bending ofElectrode GraphiteC 10
8、39 Test Methods for Apparent Porosity, Apparent Spe-cific Gravity, and Bulk Density of Graphite Electrodes3. Terminology3.1 Definitions:3.1.1 core sample the portion of graphite obtained froman electrode by use of a sampling device such as described in4.1.3.1.2 test specimenan article prepared from
9、a coresample.4. Significance and Use4.1 Core sampling is an acceptable way of obtaining a testspecimen without destroying the usefulness of the electrode.4.1.1 Test specimens obtained by this practice can be usedby producers and users of graphite electrodes for the purpose ofconducting the tests in
10、Note 1 to obtain comparative physicalproperties.4.2 This practice may not provide a test specimen of theappropriate size (with respect to particle size/sample dimensionratios) to allow the determination of absolute property values.5. Apparatus5.1 Core Drill Bit, similar to that shown in Fig. 1, driv
11、en bysuitable equipment.6. ProcedureNOTE 2When core sampling a machined electrode, use caution toprevent damage to the socket threads and remove all dust from the threadswhen the coring operation is finished.6.1 The core sample shall be taken from either end of theelectrode as close to the center of
12、 the diameter as feasible.6.2 The core drill bit dimensions shall be such that a coresample with a minimum diameter of 50 mm (2 in.) and aminimum finished length of 191 mm (7.5 in.) can be obtained.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and
13、 is the direct responsibility of Subcommittee D02.F0 onManufactured Carbon and Graphite Products.Current edition approved June 1, 2005. Published August 2005. Originallyapproved in 1974. Last previous edition approved in 2000 as C 78385(2000).2For referenced ASTM standards, visit the ASTM website, w
14、ww.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 C700, West Conshohocken, PA 19428-2959, United States.6.3
15、 Place the core drill bit firmly against the graphite.6.4 Take care to maintain the bit level and true. Do not stopuntil the bit is embedded its full length.6.5 To remove the bit, pull and twist it by hand. Do notremove the bit while it is rotating.6.6 To remove the core sample, insert a wedge betwe
16、en itand the electrode until the core sample snaps.7. Keywords7.1 carbon; core; electrodes; graphite; sample; testspecimensASTM 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 expr
17、essly 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 years andif not revise
18、d, 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 committee, which you may
19、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 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).FIG. 1 Typical Core Drill BitC 783 85 (2005)2
