ASTM_C_695_-_15.pdf

Designation:C69515An American National StandardStandard Test Method forCompressive Strength of Carbon and Graphite1This standard is issued under the fixed designation C695;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the com-pressive strength of carbon and graphite at room temperature.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 compressive strength,nproperty of solid materialthat indicates its ability to withstand a uniaxial compressiveload.4.Significance and Use4.1 Carbon and graphite can usually support higher loads incompression than in any other mode of stress.This test,therefore,provides a measure of the maximum load-bearingcapability of carbon and graphite objects.5.Apparatus5.1 Test Machine,conforming to Practice E4 and to therequirements for speed of testing prescribed in Section 8 of thistest method.5.2 Spherical Bearing Blocks attached to the upper or lowerhead of the machine in such a manner that the sphericalsurfaces are in full contact when not loaded.The center ofcurvative of the spherical surface shall lie on the surface thatcontacts the specimen and on the machine axis.The sphericalsurfaces shall be well-lubricated.The radius of the sphericalsurface shall be equal to or greater than the radius of the testspecimen.5.3 Steel Contact Blocks may be used above or below thespecimen,or both,to protect fixture and test machine surfacesfrom damage,as illustrated in Fig.1 and Fig.2.Contact blocksurfaces shall be plane and parallel to within 0.0005 in./in.(0.0005 mm/mm).5.4 All load-bearing machine and fixture surfaces shall havea minimum hardness of 45 HRC and surface finish of 16 in.(0.4 m)rms maximum.Surfaces in contact with the specimenshall be flat to less than 0.0005 in./in.(0.0005 mm/mm).5.5 Examples of arrangements of the load train are shownschematically in Fig.1 and Fig.2.6.Sampling6.1 Samples may be taken from locations and orientationsthat satisfy the objectives of the test.7.Test Specimen7.1 The test specimen shall be a right cylinder with endsmachined to yield planar and parallel faces.These faces shallbe perpendicular to the cylindrical surface to within 0.001in./in.(0.001 mm/mm)of diameter total indicator reading.Allsurfaces shall have a surface finish visually comparable to 32in.(0.8 m)rms or better.Reasonable care should beexercised to assure that all edges are sharp and without chips orother flaws.7.2 The diameter of the test specimen shall be greater thanten times the maximum particle size of the carbon or graphite.The ratio of height to diameter may vary between 1.9 and 2.1.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved June 1,2015.Published July 2015.Originally approvedin 1971.Last previous edition approved in 2010 as C695 91(2010).DOI:10.1520/C0695-15.2For 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 Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 The recommended minimum test specimen size is38in.(9.5mm)diameter by34in.(19 mm)high.8.Procedure8.1 Center the specimen in the machine between the contactsurfaces.The deviation of the specimen axis from the machineaxis shall be less than 5%of the specimen diameter.Centeringcan be assisted by appropriate circles marked on the contactsurfaces.8.2 Place an appropriate guard around the specimen todeflect flying fragments at failure.8.3 Apply the load continuously,at a constant rate ofcrosshead or platen movement,and without s