ASTM_D_2240_-_15.pdf

Designation:D224015Standard Test Method forRubber PropertyDurometer Hardness1This standard is issued under the fixed designation D2240;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 covers twelve types of rubber hardnessmeasurement devices known as durometers:Types A,B,C,D,DO,E,M,O,OO,OOO,OOO-S,and R.The procedure fordetermining indentation hardness of substances classified asthermoplastic elastomers,vulcanized(thermoset)rubber,elas-tomeric materials,cellular materials,gel-like materials,andsome plastics is also described.1.2 This test method is not equivalent to other indentationhardness methods and instrument types,specifically thosedescribed in Test Method D1415.1.3 This test method is not applicable to the testing ofcoated fabrics.1.4 All materials,instruments,or equipment used for thedetermination of mass,force,or dimension shall have trace-ability to the National Institute for Standards and Technology,or other internationally recognized organizations parallel innature.1.5 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.Many of the stated dimensions in SI are direct conver-sions from the U.S.Customary System to accommodate theinstrumentation,practices,and procedures that existed prior tothe Metric Conversion Act of 1975.1.6 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prior to use.2.Referenced Documents2.1 ASTM Standards:2D374 Test Methods for Thickness of Solid Electrical Insu-lation(Withdrawn 2013)3D618 Practice for Conditioning Plastics for TestingD785 Test Method for Rockwell Hardness of Plastics andElectrical Insulating MaterialsD1349 Practice for RubberStandard Conditions for Test-ingD1415 Test Method for Rubber PropertyInternationalHardnessD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesF1957 Test Method for Composite Foam Hardness-Durometer Hardness2.2 ISO Standard:4ISO/IEC 17025:1999 General Requirements for the Com-petence of Testing and Calibration Laboratories3.Summary of Test Method3.1 This test method permits hardness measurements basedon either initial indentation or indentation after a specifiedperiod of time,or both.Durometers with maximum readingindicators used to determine maximum hardness values of amaterial may yield lower hardness when the maximum indi-cator is used.3.2 The procedures for Type M,or micro hardnessdurometers,accommodate specimens that are,by their dimen-sions or configuration,ordinarily unable to have their durom-eter hardness determined by the other durometer types de-scribed.Type M durometers are intended for the testing ofspecimens having a thickness or cross-sectional diameter of1.25 mm(0.050 in.)or greater,although specimens of lesserdimensions may be successfully accommodated under theconditions specified in Section 6,and have a Type M durometerhardness range between 20 and 90.Those specimens whichhave a durometer hardness range other than specified shall useanother suitable procedure for determining durometer hard-ness.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 Aug.1,2015.Published January 2016.Originallyapproved in 1964.Last previous edition approved in 2010 as D2240 05(2010).DOI:10.1520/D2240-15.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from International Organization for Standardization(ISO),1 rue deVaremb,Case postale 56,CH-1211,Geneva 20,Switzerland.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Significance and Use4.1 This test method is based on the penetration of a specifictype of indentor when forced into the material under specifiedconditions.The indentation hardness is inversely related to thepenetration and is dependent on the elastic modulus andviscoelastic behavior of the material.The geometry of theindentor and the applied force influence the measurementssuch that no simple relationship exists between the measure-ments obtained with one type of durometer and those