1、Designation: F1276 99 (Reapproved 2016)Standard Test Method forCreep Relaxation of Laminated Composite Gasket Materials1This standard is issued under the fixed designation F1276; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number 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 provides a means of measuring theamount of creep relaxation of a laminated composite gasketma
3、terial 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 standard d
4、oes 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 St
5、andards:2A193/A193M Specification for Alloy-Steel and StainlessSteel Bolting for High Temperature or High PressureService and Other Special Purpose ApplicationsB637 Specification for Precipitation-Hardening and ColdWorked Nickel Alloy Bars, Forgings, and Forging Stockfor Moderate or High Temperature
6、 ServiceE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodF38 Test Methods for Creep Relaxation of a Gasket MaterialF104 Classification System for Nonmetallic Gasket Materi-alsF868 Classification for Laminated Composite Gasket Mate-rials2.2 ASTM Adjuncts
7、:Relaxometer, Method B (Adjunct to Test Method F38)33. 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
8、in length of thecalibrated bolt with a dial indicator. 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 a
9、nd their ability to maintain agiven compressive stress as a function of time.Aportion 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 co
10、rrelated with field results. This testmethod may be used as a routine test when agreed uponbetween the user and the producer.5. Apparatus5.1 Relaxometer,4composed of two platens, special drilledand calibrated bolt, washer and nut composed of SpecificationA193/A193M Grade B7 or Specification B637 Gra
11、de UNSN07718, or other alloys of construction that would satisfy thecalibration Procedure (see Annex) for the test temperaturespecified and a dial 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 60.01
12、5 in.) wide by 31.75 6 0.381 mm (1.250 6 0.015 in.) long.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, 2016. Published October 2016. Originallyapproved in
13、1990. Last previous edition approved in 2009 as F1276 99 (2009).DOI: 10.1520/F1276-99R16.2For 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 Summ
14、ary page onthe ASTM website.3Detailed working drawings of this apparatus are available from ASTMHeadquarters, 100 Barr Harbor Drive, West Conshohocken, PA 194282959 USA.Order Adjunct No. 12-600-381-00.4Dario P. Bernasconi, 40 Farrington St., Stoughton, MA 02072, and Donald G.Johnson, Metal Samples,
15、P.O. Box 8, Munford, AL 36268, are suppliers of therelaxometer.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Four specimens are required per test.6.3 A minimum of three tests shall be conducted.6.4 Nominal thickness of specimens
16、 shall be that of thelaminated composite gasket.7. Conditioning7.1 When all nonmetallic layers of the laminated compositeare the same type, condition in accordance with that type asshown in Table 1.7.2 When the nonmetallic layers of the laminated compositeare of different types, the specimen shall b
17、e 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 testing is conducted outside the area ofspecified humidity, specimens shall be removed from thechamber one at a time as needed.7.3 Other condi
18、tioning 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 molybdenum disulfide have beenfound to be acceptable lubricants.8.2 Place the specimens between the platens in accordancewith Fig. 1 making
19、 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 Screw on the dial indicator assembly, finger tight, andset the dial indicator at the zero reading.8.5 Apply stress to the specimens by t
20、ightening 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 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
21、 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 to tighten the nut may be extended to 5 s maximum to allow for thelonger arc required to apply the test load.FIG. 1 Relaxometer and Dial I
22、ndicator AssemblyTABLE 1 Test Method for Creep Relaxation of LaminatedComposite Materials Conditioning for Laminated CompositeGasket MaterialsType of GasketMaterial in theNonmetallic LayersClassificationF104IdentificationFirst TwoNumeralsof Six-DigitNumberConditioningProcedureCompressed asbestos she
23、et;asbestos beater sheet;flexible graphiteF11, F12,F51, F521hat1002C(2123.6F)Cool in desiccator overanhydrous calcium chloride21 to 30C (70 to 85F)Asbestos paper and millboard F13 4 h at 100 2C (212 3.6F)Cool as in Procedure A ofClassification F104Cork compositionCork and cellular rubberF21, F23 At
24、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 humidityTreated and untreated papersfrom cellulose or otherorganic fibersF31, F32,F33, F344 h at 21 to 30C (70 to 85F)over anhydrous calciumchloride foll
25、owed 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 2C (212 3.6F)Cool in desiccator overanhydrous calcium chloride21 to 30C (70 to 85F)Nonasbestos paper andmillboardF73 4 h at 100 2C (212 3.6F
26、)Cool as in Procedure A ofClassification F104F1276 99 (2016)28.6 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 A193/A193MGrade B7 shall not exceed 204C (400F). The maximum testtemperature
27、for Grade UNS N07718 shall not exceed 482C(900F).8.7 Remove from the oven and cool to room temperature.8.8 Replace the dial indicator assembly, finger tight, and setthe dial indicator at the zero reading. Loosen the nut, withoutdisturbing the dial indicator assembly, and record the dialreading (Df).
28、8.9 Calculate the percent relaxation as follows:relaxation, % 5Do2 Df!/Do#3100 (1)9. Report9.1 Report the following information:9.1.1 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 thi
29、ckness,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 Bias510.1 Table 2 is based on a round robin test conducted in1987 in accordance with Practice E691, involving six materialstested by five laboratories. For each material, the s
30、amples wereblanked at two independent sources. Data analysis detected astatistically significant difference in the results obtained foreach blanking source. This difference biases the results byadding variation but reflects a realistic test situation.10.1.1 Each test result was the average of three
31、individualdeterminations. Each laboratory obtained two test results foreach material, a test result on material from Blanking Source 1,and a test result on material from Blanking Source 2.10.2 Five laboratories tested the following six laminatedcomposite gasket materials (Classifications F868 and F1
32、04material designations) for creep relaxation:Material9FMF1 (F = Type 1, Class 1) A9FMF1 (F = Type 5, Class 1) B9FMF2 (F = Type 1, 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
33、were prepared from laminated compositegasket sheets by cutting them to size with a steel blanking die.Tests were conducted in accordance 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 t
34、ests were conducted for 22 h at 100C (212F).The test was conducted in triplicate on each material.10.3 The precision results are given in Table 2.11. Keywords11.1 creep relaxation; deflection; gasket material; platens;relaxometer; strain; stress; temperature; torque bolt; torque loss5Supporting data
35、 have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:F03-1012.TABLE 2 Precision and Bias DataFORMAT A Precision of Creep Relaxation Test of Laminated Composite Gasket Materials Using Coefficient of VariationMethod of Presenting Results on a Percenta
36、ge BasisNOTE 1S = standard deviation, CV = % coefficient of variation = (S 100) (average), LSD = % least significant difference between two individualtest results, and based on a 95 % confidence level 522 sCVd.MaterialRelaxationValues,% AverageRepeatability(Within Laboratories)Reproducibility(Betwee
37、n 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 22.2E 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 Rel
38、axation of Laminated Composite Gasket Materials Based on Actual Units of MeasureNoteS = standard deviation, CV = coefficient of variation = (S)/(average), LSD = least significant difference between two individual test results, and based on a95 % confidence level = 2.8 (S).Table Mat Range AverageRepe
39、atability 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 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.
40、44 29.00 0.87 0.030 2.44 1.32 0.046 3.70F1276 99 (2016)3ANNEX(Mandatory Information)A1. TEST METHOD B CREEP RELAXATON APPARATUS: BOLT CALIBRATION PROCEDUREA1.1 PurposeA1.1.1 To precondition (strain relieve) the bolts at elevatedtemperature prior to calibration.A1.1.2 To calibrate the bolts after pre
41、conditioning, and on aperiodic basis after use. Bolts used at temperatures greater than205C (401F) should be recalibrated more often than boltsused at lower test temperatures.A1.1.3 To ensure that the bolt is functioning properly.Should the calibration of a bolt result in an elongation of lessthan 0
42、.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 MethodsF38, 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.
43、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 applied load.A1.2.4 Calibration Apparatus, to connect the relaxometerto the tensile machine. See Fig. A1.1.NOTE 1Parts with an a
44、sterisk are referred to as relaxometer.FIG. A1.1 Schematic of Bolt Calibration ApparatusF1276 99 (2016)4A1.3 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
45、 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 fromthe oven, cool to room temperature, and remove the load fromthe bolt
46、, 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 differ bya value that does not show a trend to decrease further from onecycle to the next. Typically, the bolts will stabilize at
47、 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 place of the gasket, andtighten the nut only finger tight. Mount the fixture in thecalibration apparatus as shown in Fig.A1.1
48、.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 attained. Maintain this load and recordthe bolt elongation by estimating to the nearest 0.0013 mm(0.00005 in.) on the dial indica
49、tor. 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 indicator 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 b
