1、Designation: D6588/D6588M 11 (Reapproved 2016)Standard Test Method forFatigue of Tire Cords (Disc Fatigue Test)1This standard is issued under the fixed designation D6588/D6588M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of fatigue oftire cords in rubber due to compression or extension, or
3、 both,using a disc fatigue tester. The fatigue is measured as a loss instrength.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of th
4、e other. Combiningvalues from the two systems may result in nonconformancewith the standard.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 pract
5、ices to determine the applicabilityof regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD885 Test Methods for Tire Cords, Tire Cord Fabrics, andIndustrial Filament Yarns Made
6、from ManufacturedOrganic-Base FibersD1776 Practice for Conditioning and Testing TextilesD6477 Terminology Relating to Tire Cord, Bead Wire, HoseReinforcing Wire, and FabricsD7269 Test Methods for Tensile Testing of Aramid Yarns3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to
7、tire cord andfabrics, see Terminology D6477.3.1.2 For definitions of other terms related to textiles, seeTerminology D123.4. Summary of Test Method4.1 disc fatigue is a measure of the strength loss of a tirecord, which is subjected to repeated stresses. The stresses areaccomplished by subjecting the
8、 tire cords, after being cured inrubber, to repeated cycles of compression and extension.4.2 The specimen of interest is the cord after it has beenstressed and later removed from the rubber in which it wasimbedded. Cord specimens are placed between strips of rubbercompound and molded into blocks. Th
9、e specimen block is thenmounted between two rotating discs that are positioned in sucha way that the specimen will undergo compression orextension, or both, as the discs rotate. After a specified numberof cycles, the cords are removed from the blocks and theirbreaking force measured on a tensile tes
10、ting machine. Thefatigue, based on the unfatigued specimen strength, is ex-pressed as a percent strength loss in fatigued specimens.5. Significance and Use5.1 This test method is not recommended for acceptancetesting of commercial shipments in the absence of reliableinformation on between-laboratory
11、 precision.5.1.1 If there are differences of practical significance be-tween the reported test results for two laboratories (or more), acomparative test should be performed to determine if there is astatistical bias between them, using competent statistical assis-tance. As a minimum, test samples sh
12、ould be used that are ashomogeneous as possible, that are drawn from a material fromwhich the disparate test results were obtained, and that arerandomly assigned in equal numbers to each laboratory fortesting. Other fabrics with established test values may be usedfor this purpose. The test results f
13、rom the two laboratoriesshould be compared using a statistical test for unpaired data, ata probability level chosen prior to the testing series. If a bias isfound, either its cause must be found and corrected, or futuretest results must be adjusted in consideration of the knownbias.1This test method
14、 is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.19 on Industrial Fibers andMetallic ReinforcementsCurrent edition approved July 1, 2016. Published August 2016. Originallyapproved in 2000. Last previous edition approved in 2011 as D6588
15、11. DOI:10.1520/D6588_D6588M-11R16.2For 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.Copyright ASTM Internation
16、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus, Materials, and Reagents6.1 Disc Fatigue Tester (see schematic drawing in Fig. 1),with capacity for 12 specimens. For actual dimensions, seepatent US 2595069. Testers with different capacity are acce
17、pt-able.6.2 Displacement Transducer, with digital readout or dialgage for setting distance between disc fatigue flanges to thenearest 0.01 mm 0.004 in.6.3 Mold, top and bottom sections with cavities in each for12 or 24 specimens with the dimensions of 10.8 by 12.7 by76.2 mm 716 by12 by 3 in. (See sc
18、hematic drawing in Fig.2). All dimensions given require an accuracy of 0.1 mm 0.04in. The top of the mold may be coated with TFE-fluorocarbonto release the specimens easily. Molds with other numbers ofcavities may be used.6.4 Weights, having a mass of 50 6 5gor1006 10 g, orboth, for tensioning yarns
19、 or cords while building specimenblocks.6.5 Curing press, capable of maintaining a minimum pres-sure of 3.5 MPa 500 psi over the total area of the moldsurface, and capable of a platen temperature control within63C 65F of the temperature specified for curing therubber compound.6.6 Guillotine, Hand-op
20、erated, capable of slicing thesample blocks (see 11.2.2).6.7 Tensile Testing Machine, CRE type, in accordance withSpecification D76.6.8 Clamps, air-actuated, flat, rubber-faced or bollard-type.6.9 Rubber Compound, with a thickness of 6.0 6 0.3 mm0.24 6 0.01 in., rolled up in polyethylene liner and f
21、ree frommoisture and contamination.NOTE 1The rubber type used, especially rubber modulus, will affectthe results.6.10 Gloves, neoprene or other solvent-resistant rubber.6.11 Solvent, 1.1.2.2 tetrachloroethylene, CHCl2CHCl2or1.1.1 trichloroethane CCl3CH3) for removing cords fromrubber.6.12 Tachometer
22、 or Stroboscope.6.13 Screwdriver, or other tightening device.7. Hazards7.1 The manufacturers material data sheets (MSDSs) shallbe used to obtain information on handling, storage, use, anddisposal of chemicals used in this test method.8. Sampling and Test Specimens8.1 Primary Sampling UnitConsider on
23、e roll of dippedtire cord fabric or a cord package as the primary sampling unit.8.2 Laboratory Sampling UnitAs a laboratory samplingunit, from each primary sampling unit prepare tabby samplesby taking a sample equal to the length of cord between theregular tabby woven at the end of the roll and a sp
24、ecial tabbywoven a short distance from the end when the roll of fabric ismanufactured. For rolls that do not have a special woven tabby,improvise a tabby by the use of gummed tape or strips ofcemented fabric applied across a section of the cord fabric togive a tabby sample length at least 0.5 m 18 i
25、n. long and atleast one tenth of the roll width wide.8.2.1 Preparation of Tabby SamplesThe handling of thesamples must be done with care. The person obtaining thesample should wear clean gloves. Cut the warp cords of thedipped fabric along the centerline of the special tabby for adistance equal to t
26、he width of the sample. If this distance is lessthan the full width of the fabric, cut the filling yarns of thesample and of the special and regular tabbies in the directionparallel with the warp cords. The resulting section of cordfabric is the tabby sample. Attach the tabby sample to a pieceof car
27、dboard or fiberboard, the length of which shall be equalto at least the length of the cord warp between tabbies. Fold thetabby portions of the sample over each end of the board, andFIG. 1 Schematic Top View of the Disc Fatigue Tester with Two SpecimensD6588/D6588M 11 (2016)2secure the sample to the
28、board with pressure-sensitive tape orstaples. Use care to avoid contact of tape or staples with thearea to be tested. Handle the sample carefully. Discard anyspecimen subjected to any bend with a diameter less than tentimes the yarn/cord thickness (or diameter). The board with thesample may be folde
29、d lengthwise and parallel with the warp forconvenience. Place the board with the fabric sample in a blackpolyethylene bag, or wrap it with several layers of blackpolyethylene film to protect the sample from ultraviolet (UV)and ozone.8.3 Test Specimens:8.3.1 Specimens Yarns or CordFrom the laboratory
30、sample, take the number of specimens needed for each block,multiplied by the number of blocks that have to be built asshown in Table 1. For Nylon, Polyester, and Rayon, take aduplicate number of specimens for unfatigued control testing.For Aramids, the unfatigued control testing is done on thelabora
31、tory sample.8.3.2 Number of Blocks for Fatigue and Control TestingPrepare the number of blocks to be fatigue tested as shown inTable 1. For Nylon, Polyester, and Rayon, take a duplicatednumber of blocks for unfatigued control testing. For Aramids,the unfatigued control testing is done on the laborat
32、ory sample.8.3.3 Label both yarn/cord specimens and block specimensto maintain specimen identity.8.4 Building Test Specimen BlocksPrepare test specimenblocks in accordance with the directions in 8.4.1 through 8.4.58.4.1 Cut a piece of rubber stock large enough to cut twostrips of 6.0 6 0.3 mm 0.24 6
33、 0.01 in. for each cavity in themold. Cut sufficient number of strips of the rubber stock.FIG. 2 Schematic View of the MoldTABLE 1 Number of Specimens (Cords) per BlockMaterial Nominal LinearDensity, DtexNumber ofSpecimens (Cords)per BlockNumberof BlocksNylon #220022005333Polyester #220022005333Rayo
34、n all 1 6Aramid all 1 6Twisted yarn ofany materialall 1 6D6588/D6588M 11 (2016)3Remove polyethylene backing from one side of rubber stripsjust prior to using. Place a strip in each of the cavities of thetwo halves of the mold with the polyethylene side up. Press therubber firmly into the cavities. A
35、 cold press may be used.Remove the polyethylene backing from the top of the rubber,leaving the rubber surface free of contamination and finger-prints.8.4.2 For packages, discard the outer layer of cord. Cutapproximately1m1ydofdipped cord. Simultaneously loadtwo adjacent cavities in the bottom mold b
36、y one end of a singlecord at the first clamp. Position the cord in the center of the firstcavity, loop it through the second clamp at the end of the mold(hang a tensioning mass on the loop to ease loading) then downthe center of the second cavity and back through the firstclamp. Tighten the first cl
37、amp on the two cord ends. Tensioneach cord with a tensioning mass of 50 g by hanging 100 g onthe loop end. Examine rear and front cord slots to be certainthat all cords are properly aligned. Adjust cords as necessarythen hold in position with masking tape at the ends of eachblock. Once the cords hav
38、e been tensioned and aligned, closethe second clamp and remove the mass. Put an identificationtag on the ends of each cord. Continue filling the remainingcavities in the bottom of the mold (see schematic drawing inFig. 2). Place top half of the mold on the bottom half.8.4.3 Place the mold assembly i
39、n the press, preheated to thespecified temperature and apply a minimum pressure of 3.5MPa 500 psi over the total area of the mold surface.Vulcanize for the specified time at the temperature.8.4.4 Reduce the pressure and remove the mold.8.4.5 Open the mold and remove the specimen blocks. Markeach blo
40、ck with identification. Trim the rubber overflow andcut the cords so that the total length in rubber and lengthextending on each side will be not less than 150 mm 6 in.Condition the specimen blocks for at least 16 h at ambientroom temperature9. Preparation of Apparatus9.1 Disc Fatigue Tester:9.1.1 S
41、et disc in the tester parallel and 25.40 6 0.02 mm 16 0.001 in. apart. Do this by setting the angle of the right discat 0 rad 0 and adjusting the left disc to the proper distance.9.1.2 Set the tester for compression and extension condi-tions using Table 2 or Eq 1 or Eq 2.M 5 DOE 2 C!/2 (1)Dt5 DO1M (
42、2)where:M = change of the original distance, mm in., if M isnegative, the distance is decreased by that amount andif M is positive, the distance is increased,DO= original distance, (25.4 mm) 1 in.,Dt= parallel testing distance of the discs,E = percent elongation/100, andC = percent compression/100.9
43、.1.3 Make the appropriate M change in the distance be-tween each pair of discs by moving the left disc in a straightline toward, or away from, the right disc until the specifiedparallel distance between the two discs has been achieved.9.1.4 Next, set the left disc to the required compression andexte
44、nsion settings as obtained from Table 2, Eq 1 , Eq 2 or bychanging the angle of the left disc. Read (and record) themaximum and minimum distances between the discs.9.2 Tensile Testing Machine Setup:9.2.1 Set the gage length at 30 mm 1.2 in., except foraramid where a gage length of 250 mm 10.0 in. is
45、 required.9.2.2 For nylon, polyester, and rayon, use flat or bollard typeclamps and set the crosshead speed at 100 % of the gage lengthper minute (Test Methods D885). For aramid, use suitablebollard type clamps and set the crosshead speed at 50 % of thegage length per minute (Test Methods D7269).10.
46、 Conditioning10.1 Rubber compound properties are best maintained bystorage in a cool, dry atmosphere. Excessive rubber compoundmoisture may lower adhesion of some fiber/rubber composites.10.2 Store samples (tabbies) or adhesive-treated cord inmoisture-proof, UV, and ozone protective bags (aluminum-c
47、oated or black polythene bags may be sufficient) at tempera-tures below 24C 75F.10.3 Condition fatigued cords and non-fatigued controlcords for at least 16 h in the standard atmosphere for testingtextiles, as described for tire cords (see Practice D1776) priorto determining breaking force.11. Proced
48、ure11.1 Flexing Specimen Blocks:11.1.1 Determine the 25.4-mm 1.0-in. position (loadingposition) for the discs and load the specimens (blocks) in thisposition. Distribute blocks of one sample evenly between bothends of the testing device. Place the specimens in slots in thediscs and slip ends of cord
49、s under the disc enclosure. Do notallow the ends to become damaged during tester operation.TABLE 2 Values for Compression and Elongation of the Different CordsFiber Compression C, (%) Elongation E, (%) Compression, (mmin.)Extension, (mm in.) Correction M, (mmin.)Parallel, Dt(mm in.)Nylon 12.5 6.3 3.18 0.875 1.60 1.063 .79 0.031 24.61 0.969Polyester 12.5 6.3 3.18 0.875 1.60 1.063 .79 .031 24.61 0.969Rayon 12.5 6.3 3.18 0.875 1.60 1.063 .79 .031 24.61 0.969Aramid 14 2 3.56 0.86 .51 1
