ASTM_C_886_-_98_2015.pdf

Designation:C88698(Reapproved 2015)An American National StandardStandard Test Method forScleroscope Hardness Testing of Carbon and GraphiteMaterials1This standard is issued under the fixed designation C886;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.1.Scope1.1 This test method covers the apparatus and procedure fordetermining the hardness of carbon and graphite materialsusing the Model C-2 scleroscope2with the hammer calibratedfor use on carbon and graphite materials with particles smallerthan 0.8 mm.31.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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:4E171 Practice for Conditioning and Testing Flexible BarrierPackagingE448 Practice for Scleroscope Hardness Testing of MetallicMaterials2.2 ANSI Standard:5ANSI C 64.1 Brushes for Electrical Machines3.Summary of Test Method3.1 The specimen is held in position,and the height ofrebound of a diamond-tipped hammer is observed and recordedas the hardness number.4.Significance and Use4.1 The scleroscope is a rebound hardness tester with a scaledivided into 140 equal parts.For carbon and graphite materials,there is no established correlation between the Scleroscopehardness scale and other hardness scales.The test is useful inthe evaluation and the manufacturing control of carbon andgraphite materials.5.Interferences5.1 Lack of alignment of the instrument,as specified inSection 10,will cause low readings.5.2 The specimen must be held firmly in position and musthave adequate support from the anvil on which the samplerests.Neglect of alignment,positioning,or support will resultin low readings.5.3 Rough surface finish,above 3175-nm AA,may causelow readings.5.4 Indentations that are superimposed or spaced too closelytogether(approximately 3 mm)will cause incorrect readings.6.Apparatus6.1 Table,or equivalent,firm,for support.6.2 Scleroscope,Model C-2,equipped with a hammercalibrated by the manufacturer for use on carbon and graphitematerials.7.Test Specimen7.1 The specimen may be of any convenient size,but testsurfaces smaller than 5 mm by 5 mm are not recommended.7.2 The recommended specimen shall have a minimumthickness of 5 mm.7.3 The test surface shall not exceed 3175 nmAAin surfacefinish.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 Oct.1,2015.Published December 2015.Originallyapproved in 1988.Last previous edition approved in 2010 as C886 98(2010)1.DOI:10.1520/C0886-98R15.2Registered trademark of the Shore Instrument and Manufacturing Co.,Inc.,80-A Commercial St.,Freeport,NY 11520,and available from Instron WorldwideHeadquarters,825 University Ave.,Norwood,MA 02062,.3This test method may be more readily understood by referring to the followingdocuments:Practice E448,ANSI C 64.1,Brushes for Electrical Machines,availablefromAmerican National Standards Institute,1430 Broadway,NewYork,NY10017,and Lysaght and DeBellis,Indentation Hardness Testing,American Chain and CableCorp.,Reinhold Publishing Co.,1969.4For 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.5Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.4 The test surface-to-opposite side parallelism shall bewithin 1%.For all specimens,the test surfaces must bemaintained normal to the axis of the scleroscope tube.8.Calibration and Standardization8.1 Check the calibration of the scleroscope with carbon testblocks obtained from the instrument manufacturer.8.2 Make a series of tests on carbon test blocks that coverthe range of hardness to be tested.8.3 Make at least five tests on each carbon test block.Do notmake any tests closer than 6 mm from the sides of the testblocks.8.4 Consider the instrument calibrated if 90%of the read-ings deviate no more than 64%,or 63 points,whichever islarger,from the mean of the hardness numbers stamped on thecarbon test blocks.9.Conditioning9.1 Allow the specimen to reach equilibrium with roomtemperature air,and t