1、Designation: D 3854 90 (Reapproved 2005)Standard Test Method forRubber ThreadResistance to Dry Heat1This standard is issued under the fixed designation D 3854; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 t
3、hread 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
4、 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 a
5、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1349 Practice for RubberStandard Temperatures forTestingD 2433 Test Methods for Rubber ThreadE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Summary of Test Method3.1 The initi
6、al physical properties of the thread are deter-mined by the appropriate test method in accordance with TestMethods D 2433. 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 chan
7、ge reported.3.2 The physical property measured in the test may be anyof those described in Sections 18 to 37 of Test MethodsD 2433; 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 norma
8、lly 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 D 2
9、433.5.2 Masonite Forms or Other Suitable Holder, to maintainthe test specimens at 100 % elongation.5.3 Circulating Hot-Air Oven, as described in SpecificationE 145, capable of maintaining temperatures of 100 6 1C (2126 1.8F) and 150 6 2C (302 6 3.6F).6. Procedure6.1 Determine the initial selected ph
10、ysical property by theprocedure given in the appropriate section of Test MethodsD 2433, using the recommended number of test specimens.NOTE 1If the Schwartz value is used, it is advisable to restrict themaximum massaging extension to 300 % to avoid excessive test specimenbreakage during massaging af
11、ter aging.NOTE 2If the stress retention at 100 % elongation is used, massagethe thread to 300 % extension for six cycles before extending to 100 % forthe stress 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
12、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 D 1349 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 t
13、able. 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.Class of Test Temperature, C (F) Time, hA (normal)B (heat resisting)A100 6 1 (212 6 1
14、.8)150 6 2 (302 6 3.6)222ATest B is more severe and is intended for use with threads classified as “heatresistant.”1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.37 on Coated Fabrics andRubber Thread.Current edition app
15、roved June 1, 2005. Published June 2005. Originallyapproved in 1979. Last previous edition approved in 2000 as D 3854 90 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informatio
16、n, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.5 After removal from the oven, maintain the test specimenunder the conditions specified in 6.3 for a minimum of 16 h
17、.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 of the initial value of the selected physical property asfollows:SRH5PaPo3 100 % (1)where:SRH= percentage of initial value of any p
18、roperty retainedby the test specimen after dry oven heat treatment,Po = initial value of the selected physical property, andPa = value of that property after the aging period.8. Report8.1 Report the following information:8.1.1 Full description of the sample and its origin,8.1.2 Physical property sel
19、ected, the test method and appa-ratus used,8.1.3 Time and temperature of aging, and8.1.4 Percentage retention of the physical property and theinitial value.9. Precision9.1 The precision of this test method for measuring resis-tance to dry heat is as specified in Test Methods D 2433.10. Keywords10.1
20、dry heat resistance; rubber threadASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risko
21、f infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this
22、standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake yo
23、ur views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3854 90 (2005)2
