ASTM_D_395_-_14.pdf

Designation:D39514Standard Test Methods forRubber PropertyCompression Set1This standard is issued under the fixed designation D395;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 These test methods cover the testing of rubber intendedfor use in applications in which the rubber will be subjected tocompressive stresses in air or liquid media.They are applicableparticularly to the rubber used in machinery mountings,vibra-tion dampers,and seals.Two test methods are covered asfollows:Test MethodSectionACompression Set Under Constant Force in Air710BCompression Set Under Constant Deflection in Air11141.2 The choice of test method is optional,but considerationshould be given to the nature of the service for whichcorrelation of test results may be sought.Unless otherwisestated in a detailed specification,Test Method B shall be used.1.3 Test Method B is not suitable for vulcanizates harderthan 90 IRHD.1.4 The values stated in SI units are to be regarded as thestandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1349 Practice for RubberStandard Temperatures forTestingD3182 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 ManufacturingIndustriesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Summary of Test Methods3.1 A test specimen is compressed to either a deflection orby a specified force and maintained under this condition for aspecified time and at a specified temperature.3.2 The residual deformation of a test specimen is measured30 min after removal from a suitable compression device inwhich the specimen had been subjected for a definite time tocompressive deformation under specified conditions.3.3 After the measurement of the residual deformation,thecompression set,as specified in the appropriate test method,iscalculated according to Eq 1 and Eq 2.4.Significance and Use4.1 Compression set tests are intended to measure the abilityof rubber compounds to retain elastic properties after pro-longed action of compressive stresses.The actual stressingservice may involve the maintenance of a definite deflection,the constant application of a known force,or the rapidlyrepeated deformation and recovery resulting from intermittentcompressive forces.Though the latter dynamic stressing,likethe others,produces compression set,its effects as a whole aresimulated more closely by compression flexing or hysteresistests.Therefore,compression set tests are considered to bemainly applicable to service conditions involving staticstresses.Tests are frequently conducted at elevated tempera-tures.5.Test Specimens5.1 Specimens from each sample may be tested in duplicate(Option 1)or triplicate(Option 2).The compression set of thesample in Option 1 shall be the average of the two specimensexpressed as a percentage.The compression set of the sample1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.10 on PhysicalTesting.Current edition approved July 1,2014.Published August 2014.Originallyapproved in 1934.Last previous edition approved in 2008 as D395 03(2008).DOI:10.1520/D0395-14.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 in Option 2 shall be the median(middle most value)of thethree specimens expressed as a percentage.5.2 The standard test specimen shall be a cylindrical diskcut from a laboratory prepared slab.5.2.1 The dimensions of the standard specimens shall be:Type1A2BThickness,mm(in.)12.5 0.5(0.49 0.02)6.0 0.2(0.24 0.01)Diameter,mm(in.)29.0 0.5(1.14 0.02)13.0 0.2(0.51 0.01)AType 1 specimen is used in Test Methods A and B.BType 2 specimen is used in Test Method B.5.2.2 When cutting the standard specimen,the circular diehaving the required inside dimensions specified in 5.2.1 shallbe rotated in a drill press or similar device and lubric