ASTM_D_746_-_20.pdf

Designation:D74620Standard Test Method forBrittleness Temperature of Plastics and Elastomers byImpact1This standard is issued under the fixed designation D746;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.Scope*1.1 This test method covers the determination of the tem-perature at which plastics and elastomers(as defined byTerminology D883)exhibit brittle failure under specifiedimpact conditions.Two routine inspection and acceptanceprocedures are also provided.NOTE1When testing rubbers for impact brittleness use Test MethodD2137.When testing plastic sheeting for impact brittleness,use TestMethod D1790.1.2 The values stated in SI units are to be regarded as thestandard.1.3 Due to the potential safety and environmental hazardsassociated with mercury-filled thermometers,the use of alter-native temperature measuring devices(such as thermocouplesand RTDs)is encouraged.WarningMercury has been designated by many regula-tory agencies as a hazardous material that can cause seriousmedical issues.Mercury,or its vapor,has been demonstrated tobe hazardous to health and corrosive to materials.Cautionshould be taken when handling mercury and mercury contain-ing products.See the applicable product Safety Data Sheet(SDS)for additional information.Users should be aware thatselling mercury and/or mercury containing products into yourstate or country may be prohibited by law.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE2This test method and ISO 974 address the same subjectmatter,but differ in technical content.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD832 Practice for Rubber Conditioning For Low Tempera-ture TestingD883 Terminology Relating to PlasticsD1790 Test Method for Brittleness Temperature of PlasticSheeting by ImpactD2137 Test Methods for Rubber PropertyBrittleness Pointof Flexible Polymers and Coated FabricsE1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometersE608/E608M Specification for Mineral-Insulated,Metal-Sheathed Base Metal ThermocouplesE1137/E1137M Specification for Industrial Platinum Resis-tance Thermometers2.2 ISO Standard:ISO 974 PlasticsDetermination of the Brittleness Tem-perature by Impact33.Terminology3.1 GeneralThe definitions of plastics used in this testmethod are in accordance with Test Method D883 unlessotherwise specified.3.2 brittleness temperaturethat temperature,estimatedstatistically,at which 50%of the specimens would probablyfail.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Proper-ties.30.07).Current edition approved June 1,2020.Published June 2020.Originallyapproved in 1943.Last previous edition approved in 2014 as D746 14.DOI:10.1520/D0746-20.2For 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.3ISO Standards Handbook 21,Vol 1.ISO Standards are available fromAmericanNational Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.3.3 failed specimenthe division of a specimen into two ormore completely separated pieces or as any crack in thespecimen which is visible to the unaided eye.4.Summary of Test Method4.1 To determine the brittleness temperature,specimens aresecured to a specimen holder using a torque wrench.Thespecimen holder is immersed in a bath containing a heat-transfer medium,which has been c