1、Designation:D674522Standard Test Method forLinear Thermal Expansion of Electrode Carbons1This standard is issued under the fixed designation D6745;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in
2、parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the determination of the coef-ficient of linear thermal expansion(CTE)for carbon anodesand cathodes used in the aluminum ind
3、ustry,in baked form,byuse of a vitreous silica dilatometer.1.2 The applicable temperature range for this test methodfor research purposes is ambient to 1000 C.The recom-mended maximum use temperature for product evaluation is500 C.1.3 This test method and procedure is based on Test MethodE228,which
4、is a generic all-encompassing method.Specificsdictated by the nature of electrode carbons and the purposes forwhich they are used are addressed by this procedure.1.4 Electrode carbons in the baked form will only exhibitprimarily reversible dimensional changes when heated.1.5 The values stated in SI
5、units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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 establish appro-priate safety,health,and envir
6、onmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standar
7、ds,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2E228 Test Method for Linear Thermal Expansion of SolidMaterials With a Push-Rod DilatometerE691 Practice for Conducting an Interlaboratory Study to
8、Determine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 linear thermal expansion,nthe change in length perunit length resulting from a temperature change.Linear ther-mal expansion is symbolically represented by L/L0,where Lis the length change of the specimen(L1L0),L0and L1are the
9、specimens lengths at reference temperature T0and test tem-perature T1,respectively.Linear thermal expansion is oftenexpressed as a percentage or in parts per million(such as m/mor 106m/m).3.1.1.1 mean coeffcient of linear thermal expansion(CTE),nThe linear thermal expansion per change in temperature
10、;the mean coefficient of linear thermal expansion is representedby:T15L/L0T51L0LT51L0L12 L0T12 T0(1)The coefficient of thermal expansion is expressed in partsper million per degree Kelvin(such as m/mK or 106m/mK).3.1.1.1 DiscussionThis has to be accompanied by thevalues of the two temperatures to be
11、 meaningful;the referencetemperature(T0)is 20 C,and the notation may then onlycontain a single number,such as 200,meaning the meancoefficient of linear thermal expansion between 20 C and200 C.3.2 Definitions of Terms Specific to This Standard:3.2.1 reference specimen,na particularly identified orped
12、igreed material sample,with well-characterized behaviorand independently documented performance.3.2.2 specimen,na representative piece of a larger body(anode,cathode,and so forth)that is considered to be fairlytypical of a portion or of the entire piece.3.2.3 vitreous silica dilatometer,na device us
13、ed to deter-mine linear thermal expansion,by measuring the difference inlinear thermal expansion between a test specimen and thevitreous silica parts of the dilatometer.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direc
14、t responsibility ofSubcommittee D02.05 on Properties of Fuels,Petroleum Coke and Carbon Material.Current edition approved May 1,2022.Published June 2022.Originallyapproved in 2001.Last previous edition approved in 2015 as D6745 11(2015).DOI:10.1520/D6745-22.2For referenced ASTM standards,visit the A
15、STM 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbo
16、r Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.14.Summary of Test Method4.1 Arepresentative specimen is placed into a vitreous silicadilatometer and heated,while its li
