1、Designation:D627217Standard Test Method forFlexural Properties of Unreinforced and Reinforced Plasticsand Electrical Insulating Materials by Four-Point Bending1This standard is issued under the fixed designation D6272;the number immediately following the designation indicates the year oforiginal ado
2、ption 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.Scope*1.1 This test method covers the determination of flexuralproperties of unreinforc
3、ed and reinforced plastics,includinghigh-modulus composites and electrical insulating materials inthe form of rectangular bars molded directly or cut from sheets,plates,or molded shapes.These test methods are generallyapplicable to rigid and semirigid materials.However,flexuralstrength cannot be det
4、ermined for those materials that do notbreak or that do not fail in the outer fibers.This test methodutilizes a four point loading system applied to a simplysupported beam.1.2 This test method describes two procedures(ProcedureAand Procedure B),the selection of which depends on thebehavior of the sa
5、mple to be tested as explained below:1.2.1 Procedure A,designed principally for materials thatbreak at comparatively small deflections.It shall be used formeasurement of flexural properties,particularly flexuralmodulus,unless the material specification states otherwise.1.2.2 Procedure B,designed par
6、ticularly for those materialsthat undergo large deflections during testing.It is suitable formeasurement of flexural strength.1.3 Comparative tests are permitted to be run according toeither procedure,provided that the procedure is found satisfac-tory for the material being tested.1.4 The values sta
7、ted in SI units are to be regarded as thestandard.The values provided in parentheses are for informa-tion only.1.5 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
8、and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1This test method is similar to ISO 14125,Method B.However,ISO 14125,Method B specifies only a load span of13thesupport span whereas D6272 also permits a load span of12the supportspan.For this reason and
9、 other differences in technical content,exerciseextreme care if attempting to compare results between the two testmethods.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD790 Test Methods for Flexural Pro
10、perties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-alsD883 Terminology Relating to PlasticsD4000 Classification System for Specifying Plastic Materi-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE4 Practices for Force Verification of Testing Mac
11、hinesE83 Practice for Verification and Classification of Exten-someter SystemsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:3ISO14125(MethodB)Fibre-ReinforcedPlasticCompositesDetermination of Flexural Properties3.Terminology3.1 Defin
12、itions:3.1.1 Definitions of terms applying to these test methodsappear in Terminology D883 and Annex A2 of Test MethodD638.4.Summary of Test Method4.1 A bar of rectangular cross section rests on two supportsand is loaded at two points(by means of two loading noses),each an equal distance from the ad
13、jacent support point.Thedistance between the loading noses(the load span)is either onethird or one half of the support span(see Fig.1).A support1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Propertie
14、s.Current edition approved March 1,2017.Published March 2017.Originallyapproved in 1998.Last previous edition approved in 2010 as D6272-10.DOI:10.1520/D6272-17.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of AST
15、MStandards 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM Inter
16、national,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.1 span-to-depth ratio of 16:1 shall be used unless there is reasonto suspect that a larger span-to
