ASTM_F_2231_-_02_2013.pdf

Designation:F223102(Reapproved 2013)Standard 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 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 describes the specimen preparation andthe 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 thisstandard.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.Referenced 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 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 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 Use5.1Brown and Lu4,5show the Charpy impact energy isrelated to the ultimate critical temperature of the rapid crackpropagation 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.The 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 precision of 60.004 J.6.2 Notching Machine,shall be capable of notching with arazor blade with a precision of 60.01 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 from 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 F17.40 on TestMethods.Current edition approved Aug.1,2013.Published October 2013.Originallyapproved in 2008.Last previous edition approved in 2002 as F2231 02(2008).DOI:10.1520/F2231-02R13.2For 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.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 Rapid 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 dimensions of the pipe.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.3 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 adistance of 40 6 0.5 mm from the end.8.Preparation of the Compression Molded Plaque8.1After 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 specific 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 time to cool from themolding t