ASTM_D_624_-_00_2012.pdf

Designation:D62400(Reapproved 2012)Standard Test Method forTear Strength of Conventional Vulcanized Rubber andThermoplastic Elastomers1This standard is issued under the fixed designation D624;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method describes procedures for measuring aproperty of conventional vulcanized rubber and thermoplasticelastomers called tear strength.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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:2D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD1349 Practice for RubberStandard Conditions for Test-ingD3182 Practice for RubberMaterials,Equipment,and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3183 Practice for RubberPreparation of Pieces for TestPurposes from ProductsD3767 Practice for RubberMeasurement of DimensionsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries2.2 ISO Standard:ISO/34 Rubber,Vulcanized Determination of TearStrength(Trouser,Angle,and Crescent Tear Pieces)33.Terminology3.1 The tear of rubber is a mechanical rupture processinitiated and propagated at a site of high stress concentrationcaused a cut,defect,or localized deformation.The followingdefinitions define different techniques for measuring the resis-tance to tear,i.e.the tear strength,required for use with thisstandard.3.2 Definitions of Terms Specific to This Standard:3.2.1 Type A tear strengththe maximum force required tocause a nick or cut in a Type A(nicked crescent)test piece togrow by tearing the rubber,divided by the thickness of the testpiece.3.2.2 Type B tear strengththe maximum force required tocause a nick or cut in a Type B(nicked tab end)test piece togrow by tearing the rubber,divided by the thickness of the testpiece.3.2.3 Type C tear strengththe maximum force required tocause a rupture of a Type C(right angle)test piece,divided bythe thickness of the test piece.3.2.4 Type T or trouser tear strengththe mean or medianforce,calculated in accordance with procedures in this method,required to propagate a tear in a Type T(trouser)test piece,divided by the thickness of the test piece.3.2.5 Type CP or constrained path tear strengththe meanor median force,calculated in accordance with procedures inthis method,required to propagate a tear in a type CP(constrained path)test piece,divided by the thickness of thetorn section.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.10 on Physical Testing.Current edition approved Jan.1,2012.Published March 2012.Originallyapproved in 1941.Last previous edition approved in 2007 as D624 00(2007).DOI:10.1520/D0624-00R12.2For 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,11 West 42ndSt.,13thFloor,New York,NY 10036.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.6 complete tracethe section of a graphical plot offorce versus jaw separation distance between the point at whichthe first peak occurs and the point at which the test isterminated.3.2.7 peaka point at which the slope of a trace changesfrom positive to negative.3.2.8 rangethe difference between the greatest and thesmallest observed test values.3.2.9 valleya point at which the slope of a trace changesfrom negative to positive.4.Summary of Test Method4.1 Atearing strain(and stress)is applied to a test specimenby means of a tensile testing machine operated withoutinterruption at a constant rate of crosshead traverse until thespecimen is completely torn.4.2 This test method measures the force per unit thicknessrequired to rupture,initiate,or propagate a tear through a sheetof rubber in the form of one of several test piece geometries:4.2.1 Type A,a razor-nicked test piece with a crescentshape,as shown in Fig.1,Die A.The force in this test pieceFIG.1 Type A,B and C Tear Test Specimen Cutting DiesD624 00(2012)2 acts in a direction substantially along the major axis(length)and perpend