ASTM F1574-2003a Standard Test Method for Compressive Strength of Gaskets at Elevated Temperatures《高温下垫圈抗压强度的标准试验方法》.pdf

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1、Designation: F 1574 03aStandard Test Method forCompressive Strength of Gaskets at ElevatedTemperatures1This standard is issued under the fixed designation F 1574; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev

2、ision. 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 determination of compres-sive strength characteristics (crush-extrusion resistance) ofgasket mate

3、rials at elevated temperature.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

4、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:2F 104 Classification System for Nonmetallic Gasket Mate-rialsF 1315 Test Method for Density of a Sheet Gasket Material3. S

5、ummary of the Test Method3.1 Specimens cut from gasket material are subjected tovarious stresses perpendicular to the flat surface of the speci-mens for a specified time at 150C (302F). Dimensionalchanges to the thickness and in the plane of the specimen aredetermined while it is under stress and af

6、ter the stress has beenremoved. A graphical display of percent deformation plottedagainst the applied stress will enable determination of acompressive yield stress point beyond which the material willno longer decrease in thickness without also extruding in theplanar dimensions. This condition is al

7、so revealed by physicalmeasurements of the change in size of the specimens in theplanar dimensions. Tests may be performed at various tempera-tures, as agreed upon between the producer and the user, todetermine the relationship between temperature and compres-sive behavior.4. Significance and Use4.1

8、 The compressive strength or crush-extrusion resistanceof a gasket material is a major factor with regard to theselection of a given material for use in a particular sealingapplication. The significance of the test method is based, inpart, on the assumption that a material, once it has beencrushed o

9、r extruded, will no longer function as effectively as aseal. This assumption can only be used as a guide, however,since exact yield or failure points are difficult to define forgasket materials (which are usually viscoelastic in nature). Twoor more materials can be compared to determine differences

10、intheir resistance to compressive stress. A sample of material canbe compared to an established standard or previously deter-mined characteristics on original lots of the same material, forquality assurance purposes. See 6.2 for discussion of specimenarea and geometry effects.5. Apparatus5.1 Testing

11、 Machine3, for applying a known value of com-pressive stresses to specimens. The machine should be capableof applying a stress of up to 520 MPa (75 400 psi) (toleranceof 65 %), depending on the indent resistance of the steelplatens and the means of reading the applied load.5.2 Hardened Steel Platens

12、, Two (Rockwell of C35 to 40 orequivalent), circular shape, larger than the specimen diameter.A suitable size is a diameter of approximately 100 mm (3.94in.). The surface finish shall be RMS 0.25 to 0.50 m (10 to 20m). Fig. 1 shows a suitable arrangement of steel platens andtest specimen.5.3 Device

13、for Applying Heat to Platens sufficient toachieve a desired temperature at interface with gasket materialspecimens. An example of this device is also shown in Fig. 1,where a resistance heater surrounds the hardened platens. Insome cases, the loading device itself may be heated, such aswith a hot pre

14、ss. Any appropriate means is acceptable. Therecommended elevated temperature is 150 6 5C (302 6 9F).Other temperatures may be employed as desired, or as agreedupon between the producer and the user.1This test method is under the jurisdiction of ASTM Committee F03 on Gasketsand is the direct responsi

15、bility of Subcommittee F03.20 on Mechanical TestMethods.Current edition approved Oct. 1, 2003. Published October 2003. Originallyapproved in 1995. Last previous edition approved in 2003 as F 1574 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service

16、 at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Examples of such equipment include Baldwin-Southwark, Instron, Tinius-Olsen, MTS, or any type of pressing device which has been properly calibrated toapply a kno

17、wn force.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Temperature Measuring Device for use at interface,such as a thermocouple assembly and a means for recording thevoltage.5.5 DiesCutting dies for specimens of desired size an

18、dshape. The inside faces of the dies shall be polished and beperpendicular to the plane formed by the cutting 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

19、concen-tric.5.6 Lead Pellets, Solder Plugs, or Similar Soft MetallicParticles, approximately 1.6 mm 0.063 in. in diameter.5.7 Micrometer, for making specimen thickness measure-ments in accordance with Classification F 104.5.8 Micrometer, for measuring metallic particle thickness.5.9 Vernier Calipers

20、 or other suitable device for makinglinear dimensional measurements in the plane of the speci-mens, capable of reading to the nearest 0.025 mm (0.001 in.) orless.6. Test Specimens6.1 The gasket shall be die cut in the shape of an annulus,which may be considered indicative of an area of a gasket. The

21、area shall be sufficiently small as to allow an applied stress ofup to 520 MPa (75 400 psi) (65 %). Three specimens shouldbe prepared for each applied stress at which the material is tobe evaluated.6.2 The recommended annular specimen size is 23.8 6 0.5mm (0.937 6 0.02 in.) outside diameter by 12.7

22、6 0.5 mm(0.500 6 0.02 in.) inside diameter. Therefore, this size willhave an annular width of approximately 5.5 mm (0.219 in.),where the annular width is the difference between the outer andinner radius. The area will be approximately 323 mm2(0.5in.2). If, because of loading capacity or agreement be

23、tween theproducer and the user, a specimen of different area is tested, itis recommended that the annulus width be kept constant at 5.5mm (0.219 in.) so as not to introduce additional variation to thetest. If comparisons between two or more laboratories are to bemade, the specimen area and annulus w

24、idth should be thesame.6.3 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 thi

25、s test method, otherthan to acknowledge it will most likely influence the resultsand should be a part of the report as specified in Section 10.See Table 3 in Classification F 104 for recommended thick-nesses for different types of materials.7. Conditioning7.1 Condition the cut specimens in accordanc

26、e with theappropriate procedure specified in Classification F 104 withrespect to the type of gasket material from which the specimensare cut.8. Procedure8.1 Determine applied stress at which the gasket materialwill be evaluated. It should be representative of typicaloperating conditions for the gask

27、ets made of the material, andshould include additional higher and lower stress conditionswhen a full range evaluation of the material is desired. Severaldifferent stresses should be selected to cover the entire range.A series of stresses in increments of 70 MPa (10 152 psi) isrecommended, to a maxim

28、um of 520 MPa (57 400 psi) or untilextrusion has obviously occurred. Smaller steps may be re-quired for some materials to more accurately define theextrusion range. The tolerance for each stress employed shouldbe no more than 65%.8.2 Prepare the testing machine by arranging the steelplatens to accom

29、modate the test specimens. Verify that thetemperature of the platen interface is at 150 6 5C (302 69F), as required for the test.FIG. 1 Device for Testing Gasket for Compressive Strength at Elevated TemperatureF 1574 03a28.3 Measure and record the original thicknesses of eachspecimen, in accordance

30、with the method described in Classi-fication F 104 for the particular type of material. Weigh eachspecimen, calculate and record the density in accordance withTest Method F 1315 to the nearest 0.001 g. The density of allsamples used should be within 1 % of each other.8.4 Measure the initial annulus

31、width of the test specimen atfour locations 90 apart, taking the average, and record this asthe initial annulus width. For materials of the same composi-tion, and cut with the same die, the measurement on one or twospecimens can be considered representative of all specimensprior to testing. The annu

32、lus width can best be determined witha set of vernier calipers which can be used to measure thedifference between the outer and inner radii. For materials ofthe same composition and cut with the same die, the measure-ments made on one or two specimens can be consideredrepresentative of all specimens

33、 prior to testing.8.5 Open the testing device and place a test specimen on thecenter of the lower platen. Place four lead pellets or solderplugs (approximately 1.6 mm (0.063 in.) in diameter) on theplaten approximately 6 mm (0.24 in.) from the outer edge ofthe specimen, 90 apart.8.6 Close the testin

34、g device with the upper platen in positionover the specimen and lower the platen, using minimal contactforce. When performing tests at elevated temperature, hold inthis position for 30 s to enable heating of the specimen.8.7 Apply the desired load at a rate of 45 000 N (10 116lb)/min until the desir

35、ed load is achieved; then remove the loadfrom the test specimen within 5 s. (See 8.1 for description ofdesired stress.)8.8 Remove the test specimen from the device, and measureand record the final thickness in the same manner as was donefor the original thickness.8.9 Measure the final annulus width

36、of the test specimen atfour locations 90 apart, taking the average, and record this asthe extruded annulus width.8.10 Measure the thickness of the lead pellets or solderplugs, take the average of the four plugs, and record this as thespecimen thickness under stress, as it will be equivalent to thatc

37、haracteristic since the metal particles will not recover inthickness when the applied stress is removed.8.11 After each test, clean the platens appropriately torestore them to their original condition. Wipe the surfaces witha solvent, such as acetone, using a soft cotton cloth to ensurethat the surf

38、ace is clean.8.12 Repeat the test procedure on two additional specimensof the same material at the same applied stress, until thesespecimens have been so evaluated at each selected stress.8.13 Repeat the test procedure on three new specimens ofthe material being evaluated, at each additional level o

39、f appliedstress to be studied. A series of stresses in steps of 70 MPa(10 152 psi) is recommended, to a maximum of 520 MPa(75 400 psi) or until extrusion has obviously occurred. Smallersteps may be required for some materials to more accuratelydefine the extrusion range. The tolerance for each repor

40、tedstress should be no more than 65%.9. Calculation9.1 Determine the percent deformation (thickness reduc-tion) under applied stress for each specimen, as follows:Ds5 To2 Ts(1)% Ds5To2 TsTo3 100 % (2)where:Ds= deformation under applied stress,To= original thickness, andTs= thickness under stress.9.2

41、 Determine the percent final deformation for each speci-men as follows:Df5 To2 Tf(3)% Df5To2 TfTo3 100 % (4)where:Df= final deformation,To= original thickness, andTf= final thickness.9.3 Determine the percent annular deformation for eachspecimen as follows:AD 5 Wf2 Wo(5)% AD 5Wf2 WoWo3 100 % (6)wher

42、e:AD = annular deformation,Wo= original annulus width, andWf= final annulus width.9.3.1 Record the results for each of the given calculationsfor the three specimens tested at a given stress, and determinethe average values.9.4 Repeat the calculations on the specimens tested at eachadditional stress,

43、 again determining the average figures.9.5 If a graphical display of test results is desired, plot theapplied stress on the x-axis. The y-axis may include: (1) thepercent deformation under stress; (2) the percent final defor-mation, or (3) the percent annular deformation. The compres-sive yield stre

44、ss point will be observed on the graph as thepoint where there is a change in slope of the line. This changemay be large or small, depending on the nature of the gasketmaterial.10. Report10.1 Report the following information for each materialtested:10.1.1 Material identification,10.1.2 Size, shape,

45、and density of the specimens, and10.1.3 Temperature of the test.10.2 Report the following for each applied stress at whichmaterial was tested:10.2.1 Applied stress,10.2.2 Original thickness,10.2.3 Thickness under stress,F 1574 03a310.2.4 Final thickness,10.2.5 Percent deformation under stress,10.2.6

46、 Percent final deformation,10.2.7 Percent annular deformation,10.2.8 Graphical display of results if desired, and10.2.9 Compressive yield stress point determined fromplotted curves.10.3 Tested specimens may be mounted on a display sheetto illustrate the degree of extrusion.11. Precision and Bias11.1

47、 PrecisionThe precision of this test method is beingdetermined.11.2 BiasSince there is no accepted reference materialsuitable for determining the bias for this test method, nostatement on bias is available.12. Keywords12.1 annulus; compression; compressive strength; compres-sive yield; crush-extrusi

48、on; deformation; failure; gasket mate-rial; stressASTM 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 right

49、s, and the riskof 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 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 n