1、Designation: F2837 10Standard 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:2F104 Classification System for Nonmetallic Gasket Mate-rials3. Terminology3.1 Symbols:T0= original specimen thicknessT1= cold thickness under load (specimen thickness after a5-min hold under load at room temperature)T2= hot thickness under load (specime
6、n thickness at maxi-mum test temperature under load)T3= final specimen thickness (after specimen has beenremoved from the machine and cooled)Ts0= original calibration ring thicknessTs1= calibration ring thickness (after a 5-min hold underload at room temperature)Ts2= calibration ring thickness (at m
7、aximum test tempera-ture under load)Ts3= final calibration ring thickness (after specimen hasbeen removed from the machine and cooled)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
8、 temperature, and then the temperature isincreased at a defined rate while the stress remains constant.The recommended maximum temperature 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 gask
9、et is under stress and after the stress hasbeen removed. Tests may be performed on a gasket material atvarious temperatures or stresses as agreed upon between theproducer and the user, to determine the relationship betweentemperatures at a constant stress.5. Significance and Use5.1 The hot compressi
10、on properties of a gasket material,including creep resistance and compression set, are a majorfactor with regard to the selection of 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 muc
11、h creep at elevated temperature that it will nolonger function as effectively as a seal. This assumption canonly be used as a guide; however, since exact yield or failurepoints are difficult to define for gasket materials (which areusually viscoelastic in nature). Two or more materials can becompare
12、d to determine differences in their hot compressionproperties. 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 orcalib
13、ration ring described in 6.3 and Fig. 1 so that the area(2042 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 o
14、f65 %), depending on the indent resistance of the steel platensand the means of reading the applied load.1This 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 May 1, 2010.
15、Published August 2010. DOI: 10.1520/F2837-10.2For 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.1Copyright ASTM
16、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 pl
17、atens shall be plane parallel with a surfacefinish of 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
18、 mm (2.953 6 0.02 in.) outsidediameter by 55 6 0.5 mm (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
19、 for Applying Heat to Platens, sufficient toachieve a 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 con
20、stant rate of 8C (14F) per minute. Thetemperature difference 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 Dev
21、ice, for use at interface,such as a thermocouple assembly 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 e
22、stimated to the nearest 0.002 mm(0.0001 in.).6.7 ShieldA 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 cuttin
23、g edges for adepth 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 Classification F1
24、04.6.10 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, Inconel, nicke
25、l, stainlesssteel), capable of low creep at the desired maximum testFIG. 1 Test Assembly for Determining Hot CompressionF2837 102temperature 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 Class
26、ification F104)Thegasket shall be die cut in the shape 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 specimen
27、s should beprepared for each material that is to be evaluated.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 t
28、est results is not being addressed in this test method, 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-P
29、lace Gasketing (see ClassificationF104):7.2.1 A 211-mm (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 6.3
30、5 6 1.59 mm (0.25 6 0.0625 in.)overlap to complete the 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
31、thickness measurements depend on theeffects of thermal 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
32、 values Ts0, Ts1, Ts2, and Ts3, (whichcorrespond to T0, 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 I
33、t is recommended that the test machine be calibratedapproximately 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
34、 withrespect to the type of gasket material from which 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
35、 spaced placesapproximately 120 apart, the result is 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 placedbetwee
36、n new pieces of metal foil. Center the specimen or thespecimen 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 t
37、he specimen and lower the platen, using minimalcontact 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
38、of the stand. If this happens, or if the test machine 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, 6
39、5 %). Thisconstant load is to be maintained throughout 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,
40、 typically 300 6 5C (572 6 9F), whilemaintaining a constant 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 te
41、mperature, record the specimenhot thickness under load 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 describe
42、d in 6.10 may be used.10.8.2 Solid Form-in-Place GasketingBefore 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.10.8.3 After each test, clean t
43、he platens appropriately torestore them to their 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
44、 data must be adjusted for T0as described in10.4, 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.F2837 10311. Calculation11.1 Thickness Decrease Cold, % =T0 T1T03 10011.2
45、Thickness Decrease Hot, % =T1 T2! Ts1 Ts2!T13 10011.3 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 Repor
46、t the following information for each materialtested:12.1.1 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 decr
47、ease cold results,12.1.9 Thickness decrease hot results,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,
48、and each8C (14F) interval, T2, and T3. Give specific thickness of thespecimen and gasket stress.13. Precision and Bias13.1 PrecisionThe precision of the test method is beingdetermined.13.2 BiasSince there is no accepted reference materialsuitable for determining the bias for this test method, nostat
49、ement on bias is available.14. Keywords14.1 cold creep; compression; compression set; creep; gas-ket; gasket compression; hot compression; hot creep; strain;stress; thickness changeASTM 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 riskof infringement of such rights, are entirely their own responsibility.This standard is sub
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