ASTM F1276-1999(2003) Standard Test Method for Creep Relaxation of Laminated Composite Gasket Materials《复合密封材料的蠕变松弛试验方法》.pdf

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1、Designation: F 1276 99 (Reapproved 2003)Standard Test Method forCreep Relaxation of Laminated Composite Gasket Materials1This standard is issued under the fixed designation F 1276; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th

2、e year of last revision. 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 provides a means of measuring theamount of creep relaxation of a laminated composite gaske

3、tmaterial at a predetermined time after a compressive stress hasbeen applied.1.2 Creep relaxation is measured by means of a calibratedbolt with dial indicator.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standar

4、d 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

5、 Standards:A 193/A 193M Specification for Alloy-Steel and StainlessSteel Bolting Materials for High-Temperature Service2B 637 Specification for Precipitation-Hardening Nickel Al-loy Bars, Forgings, and Forging Stock for High-Temperature Service3E 691 Practice for Conducting an Interlaboratory Study

6、toDetermine the Precision of a Test Method4F 38 Test Methods for Creep Relaxation of a Gasket Mate-rial5F 104 Classification System for Nonmetallic Gasket Mate-rials5F 868 Classification for Laminated Composite Gasket Ma-terials52.2 ASTM Adjuncts:Relaxometer, Method B (Adjunct to Test Method F 38)63

7、. Summary of Test Method3.1 In this test method, the specimen is subjected to acompressive stress between two platens, with the stress appliedby a nut and bolt. Run at room or elevated temperatures, thestress is determined by measuring the change in length of thecalibrated bolt with a dial indicator

8、. The bolt length ismeasured at the beginning of the test and at the end of the test.The percent relaxation is calculated from this.4. Significance and Use4.1 This test method is designed to compare related mate-rials under controlled conditions and their ability to maintain agiven compressive stres

9、s as a function of time. A portion of thetorque loss on the bolted flange is a result of creep relaxation.Torque loss can also be caused by elongation of the bolts,distortion of the flanges, and vibration; therefore, the resultsobtained should be correlated with field results. This testmethod may be

10、 used as a routine test when agreed uponbetween the user and the producer.5. Apparatus5.1 Relaxometer,7composed of two platens, special drilledand calibrated bolt, washer and nut composed of SpecificationA 193/A 193M Grade B7 or B 637 Grade UNS N07718, orother alloys of construction that would satis

11、fy the calibrationProcedure (see Annex) for the test temperature specified and adial indicator assembly as shown in Fig. 1.5.2 Box End Wrench.5.3 Steel Blanking Die.6. Test Specimens6.1 Specimen size shall be 10.16 6 0.381 mm (0.400 60.015 in.) wide by 31.75 6 0.381 mm (1.250 6 0.015 in.) long.6.2 F

12、our specimens are required per test.6.3 A minimum of three tests shall be conducted.1This test method is under the jurisdiction of ASTM Committee F03 on Gasketsand is the direct responsibility of Subcommittee F03.20 on Mechanical TestMethods.Current edition approved Oct. 1, 2003. Published October 2

13、003. Originallyapproved in 1990. Last previous edition approved in 1999 as F 1276 99.2Annual Book of ASTM Standards, Vol 01.01.3Annual Book of ASTM Standards, Vol 02.04.4Annual Book of ASTM Standards, Vol 14.02.5Annual Book of ASTM Standards, Vol 09.02.6Detailed working drawings of this apparatus ar

14、e available from ASTMHeadquarters, 100 Barr Harbor Drive, West Conshohocken, PA 194282959 USA.Order Adjunct No. 12-600-381-00.7Dario P. Bernasconi, 40 Farrington St., Stoughton, MA 02072, and Donald G.Johnson, Metal Samples, P.O. Box 8, Munford, AL 36268, are suppliers of therelaxometer.1Copyright A

15、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Nominal thickness of specimens shall be that of thelaminated composite gasket.7. Conditioning7.1 When all nonmetallic layers of the laminated compositeare the same type, condition in accordance

16、 with that type asshown in Table 1.7.2 When the nonmetallic layers of the laminated compositeare of different types, the specimen shall be conditioned for 22h in a controlled-humidity room or in a closed chamber of airat 21 to 30C (70 to 85F) and 50 to 55 % relative humidity. Inall cases where testi

17、ng is conducted outside the area ofspecified humidity, specimens shall be removed from thechamber one at a time as needed.7.3 Other conditioning may be as agreed upon between theproducer and the user.8. Procedure8.1 Clean all surfaces and lightly lubricate the washer andbolt threads; graphite and mo

18、lybdenum disulfide have beenfound to be acceptable lubricants.8.2 Place the specimens between the platens in accordancewith Fig. 1 making sure they are no closer than 2 mm (0.078in) to the other pieces and the edge of the platens.8.3 Place the washer in position and screw on the nut, fingertight.8.4

19、 Screw on the dial indicator assembly, finger tight, andset the dial indicator at the zero reading.8.5 Apply stress to the specimens by tightening the nut witha wrench until the desired dial indicator reading is reached;record the reading (Do). Apply the stress in one continuousmotion with a maximum

20、 loading time of 3 s. A bolt elongationof 0.1222 to 0.1270 mm (0.00481 to 0.00500 in.) is typical fora compressive force of 26.7 kN (6000 lbf). Remove the dialindicator assembly. (The calibration procedure is outlined inAnnex A1.)NOTE 1When testing materials thicker than 0.8 mm (0.03 in.), thetime t

21、o tighten the nut may be extended to 5 s maximum to allow for thelonger arc required to apply the test load.8.6 Place the specimen unit in a hot air-circulating oven for22hat1006 2C (212 6 3.6F), unless otherwise specified.The maximum test temperature for Specification A 193/A 193M Grade B7 shall no

22、t exceed 204C (400F). Themaximum test temperature for Grade UNS N07718 shall notexceed 482C (900F).FIG. 1 Relaxometer and Dial Indicator AssemblyTABLE 1 Test Method for Creep Relaxation of LaminatedComposite Materials Conditioning for Laminated CompositeGasket MaterialsType of GasketMaterial in theN

23、onmetallic LayersClassificationF 104IdentificationFirst TwoNumeralsof Six-DigitNumberConditioningProcedureCompressed asbestos sheet;asbestos beater sheet;flexible graphiteF11, F12,F51, F521hat1006 2C (212 6 3.6F)Cool in desiccator overanhydrous calcium chloride21 to 30C (70 to 85F)Asbestos paper and

24、 millboard F13 4 h at 100 6 2C (212 6 3.6F)Cool as in Procedure A ofClassification F 104Cork compositionCork and cellular rubberF21, F23 At least 46 h at 21 to 30C(70 to 85F) and 50 to 55 %relative humidityCork and rubber F22 At least 46 h at 21 to 30C(70 to 85F) and 50 to 55 %relative humidityTreat

25、ed and untreated papersfrom cellulose or otherorganic fibersF31, F32,F33, F344 h at 21 to 30C (70 to 85F)over anhydrous calciumchloride followed immediatelyby at least 20 h at 21 to 30C(70 to 85F) and 50 to 55 %relative humidityCompressed nonasbestossheet; nonasbestos beatersheetF71, F72 1 h at 100

26、6 2C (212 6 3.6F)Cool in desiccator overanhydrous calcium chloride21 to 30C (70 to 85F)Nonasbestos paper andmillboardF73 4 h at 100 6 2C (212 6 3.6F)Cool as in Procedure A ofClassification F 104F 1276 99 (2003)28.7 Remove from the oven and cool to room temperature.8.8 Replace the dial indicator asse

27、mbly, finger tight, and setthe dial indicator at the zero reading. Loosen the nut, withoutdisturbing the dial indicator assembly, and record the dialreading ( Df).8.9 Calculate the percent relaxation as follows:relaxation, % 5 Do2 Df!/Do# 3 100 (1)9. Report9.1 Report the following information:9.1.1

28、Identification and designation number of the materialtested,9.1.2 Test temperature,9.1.3 Length of the test, in hours,9.1.4 “Initial stress” used and the specimen thickness,9.1.5 Percent stress loss for each specimen, and9.1.6 Average of all the results recorded in 9.1.5.10. Precision and Bias810.1

29、Table 2 is based on a round robin test conducted in1987 in accordance with Practice E 691, involving six materi-als tested by five laboratories. For each material, the sampleswere blanked at two independent sources. Data analysisdetected a statistically significant difference in the resultsobtained

30、for each blanking source. This difference biases theresults by adding variation but reflects a realistic test situation.10.1.1 Each test result was the average of three individualdeterminations. Each laboratory obtained two test results foreach material, a test result on material from Blanking Sourc

31、e 1,and a test result on material from Blanking Source 2.10.2 Five laboratories tested the following six laminatedcomposite gasket materials (Classifications F 868 and F 104material designations) for creep relaxation:Material9FMF1 (F = Type 1, Class 1) A9FMF1 (F = Type 5, Class 1) B9FMF2 (F = Type 1

32、, Class 2) C9FMF2 (F = Type 7, Class 2) D9FMF1 (F = Type 1, Class 2) E9FMF1 (F = Type 7, Class 2) F10.2.1 Table 2 conditioning was used by all laboratories.Test specimens were prepared from laminated compositegasket sheets by cutting them to size with a steel blanking die.Tests were conducted in acc

33、ordance with this test method, withan initial stress of 20.68 MPa (3000 psi) applied on a 1290mm2(2 in.2) sample area, total of 26.7 kN (6000 lb) compres-sive force. The tests were conducted for 22 h at 100C (212F).The test was conducted in triplicate on each material.10.3 The precision results are

34、given in Table 2.11. Keywords11.1 creep relaxation; deflection; gasket material; platens;relaxometer; strain; stress; temperature; torque bolt; torque loss8Supporting data are available from ASTM Headquarters. Request RR: F03-1012.TABLE 2 Precision and Bias DataFORMAT A Precision of Creep Relaxation

35、 Test of Laminated Composite Gasket Materials Using Coefficient of VariationMethod of Presenting Results on a Percentage BasisNOTES = standard deviation, CV = % coefficient of variation = (S 3 100)/(average), LSD = % least significant difference between two individual testresults, and based on a 95

36、% confidence level = 2 =2(CV).MaterialRelaxationValues,% AverageRepeatability(Within Laboratories)Reproducibility(Between Laboratories)SCV,% LSD,% SCV,% LSD,%A 25.4 2.01 7.92 22.4 2.49 12.6 35.6B 8.05 0.90 11.2 31.6 1.70 23.9 67.6C 23.9 1.85 7.73 21.9 1.08 8.95 25.3D 20.5 1.11 5.44 15.4 1.15 7.84 22

37、.2E 30.5 1.52 4.98 14.1 2.93 10.8 30.6F 29.0 0.87 3.01 8.5 1.32 5.46 15.4FORMAT B Precision and Bias Table for Creep Relaxation of Laminated Composite Gasket Materials Based on Actual Units of MeasureNoteS = standard deviation, CV = coefficient of variation = (S)/(average), LSD = least significant d

38、ifference between two individual test results, and based on a95 % confidence level = 2.8 (S).Table Mat Range AverageRepeatability ReproducibilityS CV LSD S CV LSDA 19.5731.85 25.44 2.01 0.079 5.63 2.49 0.098 6.97B 4.7811.02 8.05 0.90 0.112 2.52 1.70 0.211 4.76C 18.2429.74 23.91 1.85 0.077 5.18 1.08

39、0.045 3.02D 16.8024.59 20.47 1.11 0.054 3.11 1.15 0.056 3.22E 23.3338.64 30.51 1.52 0.050 4.26 2.93 0.096 8.20F 24.6932.44 29.00 0.87 0.030 2.44 1.32 0.046 3.70F 1276 99 (2003)3ANNEX(Mandatory Information)A1. TEST METHOD B CREEP RELAXATON APPARATUS: BOLT CALIBRATION PROCEDUREA1.1 PurposeA1.1.1 To pr

40、econdition (strain relieve) the bolts at elevatedtemperature prior to calibration.A1.1.2 To calibrate the bolts after preconditioning, and on aperiodic basis after use. Bolts used at temperatures greater than205C (401F) should be recalibrated more often than boltsused at lower test temperatures.A1.1

41、.3 To ensure that the bolt is functioning properly.Should the calibration of a bolt result in an elongation of lessthan 0.114 mm (0.00450 in.) or more than 0.140 mm (0.00550in.) at 26.7 kN (6000 lbf), the bolt should be discarded.A1.2 ApparatusA1.2.1 Relaxometer, in accordance with 7.1 of Test Meth-

42、ods F 38, modified so that each platen can accept a pair of steeldowel pins.A1.2.2 Spacer, washer-shaped, 0.80 6 0.13 mm (0.031 60.005 in.) thick.A1.2.3 Tensile Testing Machine, capable of obtaining andrecording a load of 26.7 kN (6000 lbf). The maximumallowable system error equals 0.5 % of the appl

43、ied load.A1.2.4 Calibration Apparatus, to connect the relaxometerto the tensile machine. See Fig. A1.1.A1.3 ProcedureA1.3.1 If the bolts to be calibrated are new, they must bepreconditioned using the following procedure. Assemble therelaxometer without gaskets. Load the bolt to obtain a deflec-tion

44、of 0.13 6 0.0013 mm (0.00500 6 0.00005 in.) and recordthis value as the original deflection. Place the fixture in acirculating air oven preheated to 50F above the intendedmaximum test temperature. After 22 h, remove the fixture fromNOTEParts with an asterisk are referred to as relaxometer.FIG. A1.1

45、Schematic of Bolt Calibration ApparatusF 1276 99 (2003)4the oven, cool to room temperature, and remove the load fromthe bolt, measuring the deflection to the nearest 0.0013 mm(0.00005 in.). Record this deflection as the final deflection.Repeat this cycle until the original and final deflection diffe

46、r bya value that does not show a trend to decrease further from onecycle to the next. Typically, the bolts will stabilize at 3 % orless difference between the original and final deflection.NOTE A1.1Normally, seven cycles or less are sufficient to precondi-tion bolts.A1.3.2 with the steel washer in p

47、lace of the gasket, andtighten the nut only finger tight. Mount the fixture in thecalibration apparatus as shown in Fig. A1.1. Adjust the span sothat no tensile load is applied to the relaxometer bolt and set thedial indicator at zero. Apply the tensile force until a load of4.45 kN (1000 lbf) is att

48、ained. Maintain this load and recordthe bolt elongation by estimating to the nearest 0.0013 mm(0.00005 in.) on the dial indicator. Continue loading the bolt,recording the elongation at 4.45-kN increments up to 26.7 kN(6000 lbf).A1.3.3 Remove the tensile load from the relaxometer bolt.If the dial ind

49、icator does not read zero (within 0.0025 mm(0.0001 in.), reject the data. Reset the dial indicator to zeroand reload the bolt in accordance with A1.3.2, recording theelongations. Apply the loads to the relaxometer bolt threeconsecutive times, recording the elongation at the 4.45-kN(1000-lbf) increments.A1.3.4 Prepare a bolt calibration curve by plotting theaverage bolt elongation against the bolt loads on linear graphpaper. The curve must be a straight line.ASTM International takes no position respecting the validity of any patent rig