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ASTM C565-15(R2021) pdf free download

ASTM C565-15(R2021) pdf free download.Standard Test Methods for Tension Testing of Carbon and Graphite Mechanical Materials
1. Scope
1.1 These test methods cover the apparatus, specimen, and procedures for the tension testing of carbon and graphite mechanical materials with a grain size smaller than 0.79 mm. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.2.1 Exception—All of the figures are dimensioned in inches in accordance with the original standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 These test methods may be used for quality control testing of established grades of carbon and graphite materials, in the development of new grades, and for other purposes where relative strength levels are the primary quantities of interest. This test method may be applicable only if the ratio of specimen diameter to grain size, or flaw size, is greater than 5. 4.2 These test methods do not substitute for that described in Test Method C749, but are useful where less sophisticated data and less expensive techniques are sufficient. 4.3 Carbon and graphite materials exhibit significant physi- cal property differences within parent materials. Exact sam- pling patterns and grain orientations must be specified in order to make meaningful tensile strength comparisons.
5. Apparatus
5.1 Testing Machine—The machine used for tension testing shall conform to the requirements of Practices E4. The testing machine shall have a capacity that the breaking load of the test specimen falls between 10 % and 90 % of the scale capacity. 5.2 Gripping Devices—Gripping devices that conform to the principles of those illustrated in Fig. 1 shall be used (dimensions that reflect the use of SI units are permissible). These gripping devices shall be attached to the heads of the testing machine through chain connectors. Fig. 2 shows the gripping device connected to the heads. Extreme care shall be taken that the axis of the test specimen is located on the center line of the head of the testing machine.
10. Precision and Bias
10.1 These test methods are intended to be less sophisti- cated than the method described in Test Method C749. For this reason an interlaboratory test program was not performed, but rather a direct comparison of the two tensile-test techniques was made. Two graphite grades of low variability were tested by two different laboratories, one with extensive experience with Test Method C749, the other in the technique of this standard. 10.2 The details of the experiments, the data base, and the statistical analyses may be obtained from ASTM. 3 10.3 Precision—Approximately 20 specimens of the two materials were supplied for testing under these test methods and ten specimens for testing under Test Method C749. The resulting data were examined for outliers by the Dixon Test, Grubb’s T-Test, and skewness. The data sets were examined for normality by the Kolmogorov-Smirnov Test and for skew- ness and kurtosis. No outliers were found and only kurtosis for the two ten-specimen sets was found to be significant. This does not invalidate a test on means. 10.3.1 By the approximate T-test, the means for the two techniques were found to be the same for any significance level α equal to or less than 0.60 (two sided) corresponding to an observed difference in means of 0.9 %. An F-test on variance ratios between the two tests showed a significant difference at α equal to or greater than 0.025 (one sided) for the observed variance ratio of about five. 10.3.2 It is concluded that these test methods will quite satisfactorily produce mean values of tensile strengths, but are not satisfactory for producing good estimates for variance (standard deviation) unless proven by other measurement techniques for the material in question.

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