ASTM_D_3854_-_90_2010.pdf

Designation:D385490(Reapproved 2010)Standard Test Method forRubber ThreadResistance to Dry Heat1This standard is issued under the fixed designation D3854;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.1.Scope1.1 This test method covers the extent of deterioration ofrubber threads by measuring the reduction in physical proper-ties when a thread is maintained at a constant elongation underconditions more severe than those encountered in service.Thistest method is a comparative indication only;it may not bepossible to correlate the results with the actual duration of lifein service.1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.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ASTM Standards:2D1349 Practice for RubberStandard Temperatures forTestingD2433 Test Methods for Rubber Thread(Withdrawn 2012)3E145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Summary of Test Method3.1 The initial physical properties of the thread are deter-mined by the appropriate test method in accordance with TestMethods D2433.The same test pieces,maintained at 100%elongation,are subjected to aging in a circulating air oven.Theresidual physical properties are then measured and the percent-age change reported.3.2 The physical property measured in the test may be anyof those described in Sections 18 to 37 of Test Methods D2433;however,the most suitable are the Schwartz value(Section 23)or stress retention(Section 33).4.Significance and Use4.1 Conventional rubber aging tests that are normally car-ried out on unstretched test specimens are of limited use inassessing the life of rubber threads since these are usually keptextended in use.5.Apparatus5.1 Suitable test apparatus for the measurement of theselected physical property is described in Sections 19,30,and35 of Test Methods D2433.5.2 Masonite Forms or Other Suitable Holder,to maintainthe test specimens at 100%elongation.5.3 Circulating Hot-Air Oven,as described in SpecificationE145,capable of maintaining temperatures of 100 6 1 C(2126 1.8 F)and 150 6 2 C(302 6 3.6 F).6.Procedure6.1 Determine the initial selected physical property by theprocedure given in the appropriate section of Test MethodsD2433,using the recommended number of test specimens.NOTE1If the Schwartz value is used,it is advisable to restrict themaximum massaging extension to 300%to avoid excessive test specimenbreakage during massaging after aging.NOTE2If the stress retention at 100%elongation is used,massage thethread to 300%extension for six cycles before extending to 100%for thestress to be measured.6.2 Transfer the test specimen,maintained at 100%exten-sion,to the Masonite form or other suitable holder.6.3 Allow the test specimen to rest on the form for 60 6 10min in a relaxed state,in the dark,in the standard atmospheresdescribed in Section 3 of Practice D1349 for not less than 16h before the test.6.4 Place the test specimen in the circulating air oven for theperiod and temperature stated in the following table.Stabilizethe oven temperature at the desired value before placing theforms in the oven;the heat capacity must be sufficient to ensurethat the temperature is not lowered significantly when theforms are put in.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.37 on Coated Fabrics,RubberThreads and Seals.Current edition approved June 1,2010.Published December 2010.Originallyapproved in 1979.Last previous edition approved in 2005 as D3854 90(2005).DOI:10.1520/D3854-90R10.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Class of TestTemperature,C(F)Time,hA(normal)B(heat resisting)A100 1(212 1.8)150 2(302 3.6)222ATest B is more severe and is intended for use with threads classified as“heatresistant.”6.5 After removal from the oven,maintain the test specimenunder the conditions specified in 6.3 for a minimum of 16 h.6.6 Redetermine the selected property by the method usedfor the initial value in 6.1.7.Calculation7.1 Express the performance of the thread as the percentageretention