1、Designation: F2231 02 (Reapproved 2013) An American National StandardStandard Test Method forCharpy Impact Test on Thin Specimens of PolyethyleneUsed in Pressurized Pipes1This standard is issued under the fixed designation F2231; the number immediately following the designation indicates the year of
2、original 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 describes the specimen preparation andthe
3、method of measuring the impact energy of polyethyleneused in pressurized pipes.1.2 The test specimens are taken from compression moldedplaques of the resin from pellets or pipe.1.3 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thissta
4、ndard.1.4 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. Refere
5、nced Documents2.1 ASTM Standards:2D6110 Test Method for Determining the Charpy ImpactResistance of Notched Specimens of PlasticsF412 Terminology Relating to Plastic Piping Systems2.2 ISO Standard:ISO 13477 Small Scale Steady State S-4 Test33. Terminology3.1 GeneralDefinitions are in accordance with
6、Terminol-ogy F412 unless otherwise indicated.3.2 Definitions of Terms Specific to this Standard:3.3 ultimate critical temperature, (CT)for RCP in a pres-surized pipe, the temperature above which RCP is not possibleat any pressure based on ISO 13477.4. Summary of Test Method4.1 The Charpy specimen is
7、 3 mm thick and taken from acompression-molded plaque of the resin. The specimen isnotched precisely with a razor blade and tested between 19 Cand 27C.5. Significance and Use5.1 Brown and Lu4,5show the Charpy impact energy isrelated to the ultimate critical temperature of the rapid crackpropagation
8、RCP behavior as measured by the ISO 13477,S-4 test.65.2 The test method may be used to determine the impactenergy of polyethylene used in the manufacture of pipe . Thistest method involves the preparation of a small compressionmolded specimen of PE resin that is then notched in a specifiedmanner. Th
9、e specimen is then broken in a pendulum impactmachine. The impact energy is recorded in joules. The valueobtained is referred to as the Charpy impact energy.6. Apparatus6.1 Impact Tester, with input energy of 1 to 3 J and impactvelocity of about 3.0 s. The energy loss shall be measuredwith a precisi
10、on of 6 0.004 J.6.2 Notching Machine, shall be capable of notching with arazor blade with a precision of 6 0.01 mm and pressing therazor blade into the specimen.6.3 Details concerning pendulum impact machines are inTest Method D6110 section on Apparatus.7. Test Specimen7.1 The specimen is machined f
11、rom the compressionmolded plaque of the resin. The resin may come from pellets orfrom sections taken from a pipe.7.2 The specimen geometry is shown in Fig. 1.1This test method is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F1
12、7.40 on TestMethods.Current edition approved Aug. 1, 2013. Published October 2013. Originallyapproved in 2008. Last previous edition approved in 2002 as F223102(2008). DOI:10.1520/F2231-02R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
13、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Brown, N. and Lu, X., “Dependence of Rapi
14、d Crack Propagation in PE Pipeson the Plane Stress Fracture Energy of the Resin,” Polymer Engineering and ScienceVol 41, 2001, p. 1140.5Brown, N. and Lu, X., “A Simple Test to Prevent Rapid Crack Propagation,”Plastic Pipes XI, Munich, 2001, p. 583.6The critical temperature is also related to the dim
15、ensions of the pipe.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.3 The dimension tolerances are as follows: thickness = 36 0.2 mm; width = 10 6 0.2 mm; length = 80 6 1 mm; notchdepth = 2.50 6 0.02 mm. The notch is centered within
16、 adistance of 40 6 0.5 mm from the end.8. Preparation of the Compression Molded Plaque8.1 After the resin is heated to 140 to 160C, apply andremove the pressure three times. Increase the temperature to170 to 190C for 10 to 15 min without pressure. Then applyand remove the pressure three times. The s
17、pecific temperaturesthat are used depend on the melt index, a higher temperaturefor a lower melt index. The purpose of applying and removinghe pressure is to eliminate voids. Turn off the heat and applypressure. The time to cool between 130 and 190C shall begreater than 80 min. Alternatively the tim
18、e to cool from themolding temperature to room temperature shall be greater than5 h. During cooling the pressure is allowed to decreasenaturally.9. Procedure9.1 The span of the specimen on the impact machine shallbe 40 6 0.5 mm.9.2 The fracture energy shall be less than 85 % of the inputenergy. Choos
19、e the minimum input energy that satisfies thisrequirement.9.3 The pendulum impact machine shall be rigidly fixed inaccordance with Test Method D6110.9.4 The test temperature shall be between 19 and 27C, butthe impact testing of all specimens shall be conducted within arange of 6 0.5C.9.5 The notch s
20、hall be in the center of the span.9.6 Follow Test Method D6110 section 10.2 on MachinePreparation, and the sections 10.3.2 to 10.3.4 on SpecimenTesting.10. Test Results10.1 Test five specimens. Calculate the average value andthe standard deviation. Note intralaboratory repeatability is5.0% according
21、 to the precision statement in 12.1.11. Report11.1 Report the following information:11.1.1 Identify the resin by manufacturer, type, and grade,11.1.2 Thickness, width, and length of each specimen,11.1.3 Depth of notch,11.1.4 Impact energy of each specimen in joules,11.1.5 Average value and standard
22、deviation of the energiesin joules, and11.1.6 Temperature at the impact machine.12. Precision and Bias712.1 PrecisionA round robin was conducted by 6 labora-tories on 3 gas pipe resins. The intralaboratory repeatability is5.0 %. The interlaboratory reproducibility is 16.2 %.12.2 BiasNo statement on
23、bias can be made because thereis no established reference value.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 suc
24、h patent rights, and the 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 invite
25、d either for revision of 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
26、fair hearing you shouldmake 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
27、standard may be obtained 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 ASTM website (www.astm.org/COPYRIGHT/).7Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:F17-1048.FIG. 1 Geometry of Impact SpecimenF2231 02 (2013)2
