ASTM F2837-2011 Standard Test Method for Hot Compression Properties of Gasket Materials《衬垫材料的热压特性的标准试验方法》.pdf

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1、Designation: F2837 11Standard Test Method forHot Compression Properties of Gasket Materials1This standard is issued under the fixed designation F2837; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num

2、ber 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 a means of measuring the hotcompression properties of a gasket material by measuring itscreep under a constant loa

3、d at both room temperature and whileincreasing the temperature. Short term creep properties includ-ing both cold and hot creep, total creep and compression set ofa gasket material can be determined.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are f

4、or informationonly.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

5、use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodF104 Classification System for Nonmetallic Gasket Mate-rials3. Terminology3.1 Symbol

6、s:T0= original specimen thicknessT1= cold thickness under load (specimen thickness after a5-min hold under load at room temperature)T2= hot thickness under load (specimen thickness at maxi-mum test temperature under load)T3= final specimen thickness (after specimen has beenremoved from the machine a

7、nd cooled)Ts0= original calibration ring thicknessTs1= calibration ring thickness (after a 5-min hold underload at room temperature)Ts2= calibration ring thickness (at maximum test tempera-ture under load)Ts3= final calibration ring thickness (after specimen hasbeen removed from the machine and cool

8、ed)4. Summary of Test Method4.1 Specimens cut from gasket material are subjected to astress perpendicular to the flat surface of the specimen for aspecified time at room temperature, and then the temperature isincreased at a defined rate while the stress remains constant.The recommended maximum temp

9、erature limit for the test is300C (572F). The desired gasket load for the test is 25.5 MPa(3700 psi). Dimensional changes to the thickness are deter-mined while the gasket is under stress and after the stress hasbeen removed. Tests may be performed on a gasket material atvarious temperatures or stre

10、sses as agreed upon between theproducer and the user, to determine the relationship betweentemperatures at a constant stress.5. Significance and Use5.1 The hot compression properties of a gasket material,including creep resistance and compression set, are a majorfactor with regard to the selection o

11、f a given material for use ina particular sealing application. The significance of the testmethod is based, in part; on the assumption that if a materialexhibits too much creep at elevated temperature that it will nolonger function as effectively as a seal. This assumption canonly be used as a guide

12、; however, since exact yield or failurepoints are difficult to define for gasket materials (which are1This test method is under the jurisdiction of ASTM Committee F03 on Gasketsand is the direct responsibility of Subcommittee F03.40 on Chemical Test Methods.Current edition approved April 1, 2011. Pu

13、blished May 2011. Originallyapproved in 2010. Last previous edition approved in 2010 as F2837 10. DOI:10.1520/F2837-11.2For 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

14、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.usually viscoelastic in nature). Two or more materials can becompared to determine differences in their hot compressionproperti

15、es. A sample of material can be compared to anestablished standard or previously determined characteristicson original lots of the same material, for quality assurancepurposes.5.2 Samples are to be tested with a raised profile insert orcalibration ring described in 6.3 and Fig. 1 so that the area(20

16、42 mm2(3.17 in.2) remains constant during the test.6. Apparatus6.1 Testing Machine, for applying a known value of com-pressive stresses to specimens. The machine should be capableof applying a stress of up to 51.7 MPa (7500 psi) (tolerance of65 %), depending on the indent resistance of the steel pla

17、tensand the means of reading the applied load.6.2 Hardened Steel Platens, Two (Rockwell of C35 to 40 orequivalent), circular shape, larger than the specimen diameter.A suitable size is a diameter of approximately 152 mm (6 in.).The faces of the platens shall be plane parallel with a surfacefinish of

18、 0.25 to 0.50 m Ra (10 to 20 in Ra). Fig. 1 shows asuitable arrangement of steel platens and test specimen.6.3 Insert or Calibration RingA raised profile insert orcalibration ring with a minimum raised height of 1.6 mm(0.063 in.) having a 75 6 0.5 mm (2.953 6 0.02 in.) outsidediameter by 55 6 0.5 mm

19、 (2.165 6 0.02 in.) inside diametermade of the same material as the platens (Rockwell of C 35 to40 or equivalent) is required. The faces of the insert shall beplane parallel and have a surface finish of 0.25 to 0.50 m Ra(10 to 20 in Ra).6.4 Device for Applying Heat to Platens, sufficient toachieve a

20、 desired temperature at interface with gasket materialspecimens. In some cases, the loading device itself may beheated, such as with a hot press. Any appropriate means isacceptable. The device shall be capable of increasing thetemperature at a constant rate of 8C (14F) per minute. Thetemperature dif

21、ference between the two platens shall notexceed 5C (9F) at any time. The recommended elevatedtemperature is 300C (572F). Other temperatures may beemployed as desired, or as agreed upon between the producerand the user.6.5 Temperature Measuring Device, for use at interface,such as a thermocouple asse

22、mbly and a means for recording thevoltage.6.6 Dial or Thickness Measuring DeviceAn indicatingdial, or dials, graduated in 0.025 mm (0.001 in.), or a digitaldevice, to show or record the thickness of the specimen duringthe test. Readings shall be estimated to the nearest 0.002 mm(0.0001 in.).6.7 Shie

23、ldA safety shield for protection from severeoutgassing that may occur during the test.6.8 DiesCutting dies for specimens of desired size andshape. The inside faces of the dies shall be polished and beperpendicular to the plane formed by the cutting edges for aFIG. 1 Test Assembly for Determining Hot

24、 CompressionF2837 112depth sufficient to prevent any bevel on the edge. The die shallbe sharp and free of nicks in order to prevent ragged edges onthe specimen. The bore and outside diameter shall be concen-tric.6.9 Micrometer, for making specimen thickness measure-ments in accordance with Classific

25、ation F104.6.10 Water-Cooled DiscA metal disc cooled by water thatacts as a heat exchanger that can be placed between the platensto lower the temperature between tests, is recommended toshorten the cycle time between tests. Water-cooled platens maybe used as well.6.11 Metal Foil (for example, Incone

26、l, nickel, stainlesssteel), capable of low creep at the desired maximum testtemperature may be used to prevent the sample from stickingto the platens. Recommended thickness is 0.025 mm (0.001in.).7. Test Specimen7.1 Sheet-Type Gasketing (see Classification F104)Thegasket shall be die cut in the shap

27、e of an annulus with cleansmooth edges. The bore and outside diameter shall be concen-tric.7.1.1 The recommended annular specimen size is 90 6 0.5mm (3.55 6 0.02 in.) outside diameter by 50 6 0.5 mm (1.976 0.02 in.) inside diameter. Three specimens should beprepared for each material that is to be e

28、valuated.7.1.2 The recommended test specimen thickness may varydepending on the type of testing machine employed, type ofmaterial being evaluated, and the application to which theresults are directed. The exact effect of specimen thickness onthe test results is not being addressed in this test metho

29、d, otherthan to acknowledge it will most likely influence the resultsand should be a part of the report as specified in Section 12.See Table 3 in Classification F104 for recommended thick-nesses for different types of materials.7.2 Solid Form-in-Place Gasketing (see ClassificationF104):7.2.1 A 211-m

30、m (8.30-in.) long piece of standard sizematerial between 3.18 and 4.76 mm (0.125 and 0.1875 in.)nominal size or width, shall be formed into a circle of 65 mm(2.56 in.) mean diameter. The ends of the Type 4 material shallbe so laid as to have a 6.35 6 1.59 mm (0.25 6 0.0625 in.)overlap to complete th

31、e specimen. The Type 5 material shallhave an overlap of 1.59 6 0.79 mm (0.0625 6 0.0313 in.) tocomplete the specimen. Three specimens should be preparedfor each material that is to be evaluated.8. Calibration and Standardization8.1 Since accurate thickness measurements depend on theeffects of therma

32、l and mechanical characteristics on the fixture,in addition to the effect produced by the test gasket, it isnecessary that the fixture be calibrated in accordance withSection 10 using only the raised profile insert or calibrationring to obtain the values Ts0, Ts1, Ts2, and Ts3, (whichcorrespond to T

33、0, T1, T2, and T3in 10.1-10.10).8.2 If a test machine performs calibration automatically as apart of its program, the procedures in this section are notnecessary and inclusion of the values Ts0, Ts1, Ts2, and Ts3inSection 10 are not required.8.3 It is recommended that the test machine be calibrateda

34、pproximately every 100 cycles and between these periods thecalibration results from the previous test be used in Section 10.9. Conditioning9.1 Condition the cut specimens in accordance with theappropriate procedure specified in Classification F104 withrespect to the type of gasket material from whic

35、h the specimensare cut.10. Procedure10.1 Original Thickness Measurement, T0Measure thethickness of the conditioned gasket specimen according toClassification F104, section 9.1. The specimen thickness ismeasured with the micrometer at three equally spaced placesapproximately 120 apart, the result is

36、averaged and recordedas the thickness T0.10.2 The test shall begin with the platens and specimen atroom temperature. For subsequent tests the platens shall becooled to room temperature.10.3 If sticking is a problem the specimen may be placedbetween new pieces of metal foil. Center the specimen or th

37、especimen and foil combination if used, between the platenswith the raised profile insert or calibration ring. Place theassembled platens in the test fixture described in Fig. 1.10.4 Close the testing device with the upper platen inposition over the specimen and lower the platen, using minimalcontac

38、t force. Some testing machines automatically record theinitial thickness, while some testing machines only record thedifference in thickness. Depending on equipment capability,some materials will compress significantly at the lowest stresssetting of the stand. If this happens, or if the test machine

39、 onlyrecords the difference in thickness, the thickness data collectedduring the test can be adjusted using T0from 10.1 after the testis completed.10.5 Increase the pressure on the platens to the desiredgasket load (typical 25.5 MPa or 3700 psi, 65 %). Thisconstant load is to be maintained throughou

40、t the test period.After a 5-min hold at the desired gasket load, record thespecimen cold thickness under load as T1.10.6 Start the temperature program to increase the platentemperature by 8C (14F) per minute to the desired maximumtest temperature, typically 300 6 5C (572 6 9F), whilemaintaining a co

41、nstant load on the gasket throughout theduration of the test (tolerance 65C). Record the change inthickness every 8C (14F). If desired this data can be used toprovide a thickness versus temperature plot for the specimen.10.7 At the test maximum temperature, record the specimenhot thickness under loa

42、d as T2.10.8 Upon Completion of the Test:10.8.1 Sheet-Type GasketingRemove the load, separatethe platens and remove the specimen from the fixture and allowthe fixture to cool to room temperature. A water cooled disc orwater cooled platens described in 6.10 may be used.10.8.2 Solid Form-in-Place Gask

43、etingBefore removingthe load and separating the platens allow the gasket to cool inthe platens to prevent curling. After removing the specimen, awater cooled disc or water cooled platens described in 6.10may be used.F2837 11310.8.3 After each test, clean the platens appropriately torestore them to t

44、heir original condition. Wipe the surfaces witha solvent, such as acetone, using a soft cotton cloth to ensurethat the surface is clean.10.9 Repeat the thickness measurement in accordance with10.1 to obtain the final thickness and record as T3.10.10 If the data must be adjusted for T0as described in

45、10.4, do so and record the adjusted values for T1, T2, and T3.10.11 Repeat the test procedure on two additional speci-mens of the same material and the same thickness beingevaluated.11. Calculation11.1 Thickness Decrease Cold, % =T0 T1T03 10011.2 Thickness Decrease Hot, % =T1 T2! Ts1 Ts2!T13 10011.3

46、 Thickness Decrease Total, % =T0 T2! Ts0 Ts2!T03 10011.4 Total Compression Set, % =T0 T3! Ts0 Ts3!T03 10011.5 Record the results for each of the given calculations forthe three specimens tested and determine the average values.12. Report12.1 Report the following information for each materialtested:1

47、2.1.1 Material identification,12.1.2 Maximum temperature of test,12.1.3 Gasket load used for test,12.1.4 Original gasket thickness,12.1.5 Cold thickness under load,12.1.6 Hot thickness under load,12.1.7 Final gasket thickness,12.1.8 Thickness decrease cold results,12.1.9 Thickness decrease hot resul

48、ts,12.1.10 Thickness decrease total results, and12.1.11 Total compression set results, and12.1.12 Graphical display of results if desired.12.1.12.1 A plot of thickness versus temperature resultsindicating original thickness of specimen at T0, T1, and each8C (14F) interval, T2, and T3. Give specific

49、thickness of thespecimen and gasket stress.13. Precision and Bias313.1 The precision of this test method is based on anintralaboratory study conducted in 2008. Nine laboratoriestested a single type of gasketing material. Every “test result”represents an individual determination. Each laboratory wasasked to submit triplicate test results, from a single operator,for the material. Except for the analysis of only a singlematerial, Practice E691 was followed for the design andanalysis of the data.13.1.1 Repeatability Limit (r)Two test