1、Designation: D 7107 04Standard Test Method forCreep Measurement of Self-Lubricating Bushings1This standard is issued under the fixed designation D 7107; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber 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 determines the amount of creep exhib-ited by self-lubricating bushings exposed to a high load for anextended period of
3、 time.1.2 This test method is designed to reproduce conditionstypical of those encountered by trunnion bushings in hydro-power applications and any other bushings subjected to highcontinuous loading and low-speed oscillating applications.1.3 This test method is conducted on cut segments of thebushin
4、gs.1.4 The values given in SI units are to be regarded as thestandard in all property and dimensional tables.NOTE 1There is no equivalent ISO standard.1.5 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
5、 standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Terminology2.1 Definitions:2.1.1 creep strain, ntotal strain, at any given time, pro-duced by the applied stress during a creep test.3. Summary of Test Method3.
6、1 Segments of the bushing are mounted in-line on the testapparatus such that when load is applied at one end of theapparatus, by means of a hydraulic cylinder, all specimens aresimultaneously loaded exactly the same.3.2 Bearing test pressure is maintained at 55 160 kPa 8000psi on the projected area
7、of the bushing specimen.3.3 Pressure is held constant by means of an automaticpumping system and an accumulator.3.4 The actual amount of creep is measured over an ex-tended period of time.4. Significance and Use4.1 Self-lubricating bushings with low creep rates are usedin hydropower turbines and oth
8、er applications in which bush-ing distortion could cause misalignment of shafts and linkages.4.2 An assumption is made that if the creep is satisfactory at55 160 kPa 8000 psi, it will also be satisfactory at lowerpressures.5. Apparatus5.1 The loading frame shall be capable of applying andmaintaining
9、 the required load on the specimens, despite anychange in the dimensions of the specimens.5.2 Bushing specimens are mounted in-line on the testapparatus such that when load is applied at one end of theapparatus (by means of a hydraulic cylinder) all specimensreceive the same load.5.3 Bearing test pr
10、essure is maintained at 55 160 kPa 8000psi on the projected area of the bushing specimen.5.4 Pressure is held (nearly) constant by means of anautomatic pumping system and an accumulator.5.5 A suitable test frame configuration is shown in AnnexA1.5.6 The creep-measuring device consists of an eddy-cur
11、rentsensor anchored to one end of a specimen group (four testsamples) directed at a target attached to the other end of thegroup.5.7 The overall change in lengths of the four specimens ismonitored to an accuracy of 2.54 m 0.0001 in.6. Test Specimens and Test Units6.1 Paragraph 6.2 and Fig. 1 define
12、the test sample configu-ration. The samples are clamped into sample supports asdescribed in Section 7.6.2 Each test shall use four identical bushing materialspecimens meeting the following requirements (reference Fig.1):6.2.1 Inside Radius of Tubular Form6.350 6 0.013 cm2.500 6 0.005 in.,6.2.2 Thick
13、ness0.952 6 0.005 cm 0.375 6 0.002 in.,6.2.3 Length6.98 + 0.000/-0.013 cm 2.75 + 0.000/-0.005in.,6.2.4 Angle of Arc (Each Finished Specimen)120 6 1.0,and6.2.5 Surface FinishRa3.2 m 125 in. minimum.7. Preparation of Apparatus7.1 Sample Spacer:7.1.1 Material and TemperAL 6061 T6 or T6511,7.1.2 Diamete
14、r2.700 6 0.005 cm 5.000 6 0.002 in.,1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.20 on Plastic Products.Current edition approved December 1, 2004. Published December 2004.1Copyright ASTM International, 100 Barr Harb
15、or Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.1.3 Length6.985 + 0.000/-0.025 cm 2.75 + 0.000/-0.010 in.,7.1.4 PerpendicularityEnds perpendicular with cylinderaxis within 50 m 0.002 in., and7.1.5 Surface FinishRa0.4 m 16 in. minimum.7.2 Sample Supports:7.2.1 Material and Te
16、mperAL 6061 T6 or T6511,7.2.2 Radii7.302 6 0.025 cm 2.875 6 0.010 in.,7.2.3 Length6.985 + 0.000/-0.025 cm 2.75 + 0.000/-0.010 in., and7.2.4 Radii Surface FinishesRa0.8 m 32 in. mini-mum.7.3 Other Machined Parts and Sample Clamps:7.3.1 Material and TemperAL 6061 T6 or T6511 and7.3.2 FinishRa3.2 m 125
17、 in.7.4 AssemblyFIG. 1 Test Sample ConfigurationD71070427.4.1 The test specimens and the inside surface of thespecimen supports shall be cleaned with dishwashing detergentand water followed by a thorough rinse with water and dried.(Air dry thoroughly before assembly.)7.4.2 The specimen shall be plac
18、ed in the supports andclamped in place.7.4.3 The complete frame shall be assembled with speci-mens, spacers, and instrumentation.8. Calibration and Standardization8.1 Eddy-current probes are calibrated in accordance withmanufacturers recommendations.8.2 Thermocouples are calibrated in accorrdance wi
19、thmanufacturers recommendations.9. Conditioning9.1 All storage and testing of specimens shall be conductedat room temperature (18 to 25C).10. Procedure10.1 The test frames shall be set up in an area in whichtemperature changes are limited to 20 6 1C 68 6 2F.10.2 Each specimen shall be premounted in
20、the test blockand clamped in place.10.3 The four specimens for each material shall be preas-sembled as a group.10.4 Two groups of specimens shall be placed in the framebetween the tension rods.10.5 The hydraulic ram and loading block shall also be laidin the frame in alignment with the specimens.10.
21、6 The frame shall be inserted into a tank sufficiently largeto contain the entire frame.10.7 The tank shall be filled with distilled water completelycovering the test specimens.10.8 The eddy-current displacement probes shall bemounted on each group of specimens.10.9 A load of 4082 6 90 kg 9000 6 200
22、 lb is applied for24 h.NOTE 2This load is sufficient to provide pressure of 5171 kPa 750psi on the projected area of the bearing specimen.10.10 Start the recording device to log temperature anddisplacement once an hour every hour for 24 h.10.11 Apply a load of 43 200 6 227 kg 95 250 6 500 lb(that is
23、, 60.5 %) and maintain the load for 360 days.NOTE 3This load is sufficient to provide pressure of 55 160 kPa 8000psi on the projected area of the bearing specimen.10.12 Continue recording once every 4 h after the first 24h. After one month, record once a day.10.13 Monitor pressure on a weekly basis
24、and increase ifand when necessary.11. Calculation11.1 Plot displacement data (creep strain) versus elapsedtime.11.2 Determine elapsed time at which creep strain ceases.11.3 Calculate amount of creep per unit thickness of theproduct.12. Report12.1 Name of the product tested and the name and addressof
25、 the manufacturer.12.2 Displacement data (see 11.1).12.3 Observations made during test providing details of anyvariations of temperature, times when pressure (load) requiredadjustment, and details of unusual events that occurred.13. Precision and Bias13.1 Insufficient data are available at the prese
26、nt time todevelop repeatability data. The test is expensive and time-consuming (360 days). Data will be developed and addedwithin the earliest convenient timeframe.14. Keywords14.1 bushings; material creepD7107043ANNEX(Mandatory Information)A1. COMPRESSION FRAMEA1.1 The general configuration of a te
27、st frame capable ofholding two groups of four specimens is shown in Figs.A1.1-A1.3FIG. A1.1 Overview of Creep Test ApparatusD7107044FIG. A1.2 Parts Description of Creep ApparatusD7107045ASTM International takes no position respecting the validity of any patent rights asserted in connection with any
28、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 subject to revision at any time by the responsible technical c
29、ommittee 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
30、a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Dr
31、ive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. A1.3 Exploded View of Creep ApparatusD7107046
