1、Designation: C695 15 An 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 yea
2、r 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 th
3、e 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 standa
4、rd.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. Reference
5、d 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 compressi
6、ve 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-beari
7、ngcapability 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 spherica
8、lsurfaces 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 o
9、f 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 mac
10、hine 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
11、. 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 0.001
12、in./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
13、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
14、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 A
15、STM 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 Consho
16、hocken, PA 19428-2959. United States1The recommended minimum test specimen size is38 in. (9.5mm) diameter by34 in. (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 specim
17、en 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 shock until ulti-mate fa
18、ilure. Choose the rate of movement so that averagerupture time is greater than 30 s.8.4 If the test machine is equipped with a load or strainpacing device, a constant load or strain rate may be used.9. Calculation9.1 Calculate the compressive strength of each specimen asfollows:C 5 W/Awhere:C = comp
19、ressive strength of specimen, psi (or MPa),W = total load on the specimen at failure, lbf (or N), andA = calculated area of the gage section of the specimen, in.2(or mm2).10. Report10.1 The report shall include the following:10.1.1 Type of testing machine, hydraulic or screw,10.1.2 Type and size of
20、contact blocks,10.1.3 General description of material being tested,10.1.4 Dimensions, location, and orientation of specimens,10.1.5 Details of specimen preparation,FIG. 1 Elements of Compressive Strength Load TrainFIG. 2 Compressive Test Arrangement with Spherical Blocks on BottomC695 15210.1.6 Rate
21、 of crosshead or platen movement, or load rate,or strain rate,10.1.7 Load at failure, failure mode, and compressivestrength of each specimen, and10.1.8 Mean compressive strength and standard deviationfor material tested.11. Precision and Bias311.1 PrecisionThe precision statements given in this sec-
22、tion are based on the comparison of the mean strength by theStudent “t” test and carrying out the statistical analysis of thedata obtained in a round robin as recommended by PracticeE691. The round robin was carried out on two materials.11.1.1 Comparison of the MeansThe comparison of themeans by the
23、 Student “t” test leads to the conclusion that theaverage strength values measured by each laboratory on eachmaterial can be considered statistically equal at 95 % confi-dence level.11.1.2 Repeatability (Single Instrument) The precisionwithin laboratory of two single values of measured strengthusing
24、 Practice E177 definition with the pooled standard devia-tion calculated using Practice E691:Repeatability within laboratory 5 2 Sr!jwhich yields a value for the materials used in the round robinof 469 psi (3.2 MPa) for one material and 522 psi (3.6 MPa) forthe other. These values convert into stren
25、gth percentages of 65for one material and 62.5 for the other.11.1.3 Repeatability (Multi-Instrument) The precision be-tween laboratories of two single values of measured strengthusing Practice E177 definition with the component of variancebetween laboratories calculated using Practice E691 is:Repeat
26、ability between laboratories 5 2 SL!jwhich yields a value for the materials used in this roundrobin of 347 psi (2.4 MPa) for one material and 135 psi (1MPa) for the other. This converts into strength percentages of63 for one material and 61 for the other.11.2 BiasNo true statement on bias can be mad
27、e becauseno reference carbon or graphite material exists.12. Keywords12.1 carbon; compressive strength; graphiteSUMMARY OF CHANGESSubcommittee D02.F0 has identified the location of selected changes to this standard since the last issue(C695 91 (2010) that may impact the use of this standard. (Approv
28、ed June 1, 2015.)(1) Revised Section 3.ASTM 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 expressly advised that determination of the validity of any such patent rights, and the
29、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 revised, either reapproved or withdrawn. Your comments are invited either for revision of
30、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 attend. If you feel that your comments have not received a fair hearing you shouldma
31、ke 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
32、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:/ data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:C05-1010.C695 153
