1、Designation: D 6770 02e1Standard Test Method forAbrasion Resistance of Textile Webbing (Hex Bar Method)1This standard is issued under the fixed designation D 6770; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEFigure 1 was corrected editorially in May 2002.1. Scope1.1 This test method covers the determination of abrasionresistance of text
3、ile webbing using a hex bar abrasion tester.1.1.1 The resistance is expressed as a percentage of retainedbreak strength.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as the standard. Within the text,the inch-pound units are shown in parentheses. The values
4、stated in each system may not be exact equivalents; therefore,each system shall be used independently of the other. Combin-ing values from the two systems may result in nonconformancewith this test method.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wit
5、h 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 Standards:D 123 Terminology Relating to Textiles2D 1776 Practice for Condition
6、ing and Testing Textiles22.2 Other Standard:Federal Standard 191, Method 4108 “Strength and Elonga-tion, Breaking; Textile Webbing, Tape and BraidedItems”33. Terminology3.1 Definitions:3.1.1 abrasion, nthe wearing away of any part of amaterial by rubbing against another surface.3.1.2 abrasion cycle,
7、 none or more movements of anabradant across a material surface, or the material surfaceacross the abradant, that permits a return to its starting position.3.1.2.1 DiscussionThe abrasion cycle is dependent on theprogrammed motions of the abrasion machine and the teststandard used. It may consist of
8、one back-and-forth unidirec-tional movement or one circular movement, or a combinationof both. For the hex bar abrasion method a cycle is comprisedof two strokes.3.1.3 breaking force, nthe maximum force applied to amaterial carried to rupture. (Compare breaking point, breakingstrength.)3.1.4 standar
9、d atmosphere for preconditioning textiles,na set of controlled conditions having a temperature not over50C (122F), with respective tolerance of 61C (2F), and arelative humidity of 5 to 25 6 2 % for the selected humidity,so that drying can be achieved prior to conditioning in thestandard atmosphere f
10、or testing textiles.3.1.5 standard atmosphere for testing textiles,nlaboratory conditions for testing fibers, yarns, and fabrics inwhich air temperature and relative humidity are maintained atspecific levels with established tolerances.3.1.5.1 DiscussionTextile materials are used in a numberof speci
11、fic end-use applications that frequently require differenttesting temperatures and relative humidities. Specific condi-tioning and testing of textiles for end-product requirements canbe carried out as defined in Practice D 1776.3.1.6 stroke, nin hex bar abrasion testing, one-half of anabrasion cycle
12、 that consists of one forward or one backwardmotion.3.1.7 webbing, nin textiles, a stout narrow fabric with amass per unit area of at least 0.5 kg/m2(0.1 lb/ft2) for each 25.4mm (1 in.) of width. (Compare narrow fabric, ribbon, andtape.)3.2 For definitions of other textile terms used in this testmet
13、hod, refer to Terminology D 123.4. Summary of Test Method4.1 Abrasion resistance is measured by subjecting the speci-men to unidirectional reciprocal rubbing over a specific barunder specified conditions of tension, stroke length and time.Resistance to abrasion is evaluated by determining the percen
14、tretention of breaking force of an abraded specimen comparedto an unabraded specimen.5. Significance and Use5.1 The measurement of the resistance to abrasion of textile1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60
15、 on Fabrics, Specific.Current edition approved Feb. 10, 2002. Published March 2002.2Annual Book of ASTM Standards, Vol 07.01.3Available from Superintendent of Documents, Government Printing Office,Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohock
16、en, PA 19428-2959, United States.webbing is very complex. The resistance to abrasion is affectedby many factors that include the inherent mechanical propertiesof the fibers; the dimensions of the fibers; the structure of theyarns; the construction of the webbing; the type, kind, andamount of treatme
17、nt added to the fibers, yarns, or webbing; thenature of the abradant; the variable action of the abradant overthe specimen area abraded; the tension on the specimen; thepressure between the specimen and the abradant; and thedimensional changes in the specimen.5.2 The resistance of textile webbing to
18、 abrasion as mea-sured by this test method does not include all the factors whichaccount for wear performance or durability in actual use. Whilethe abrasion resistance stated in terms of the number of cyclesand durability (defined as the ability to withstand deteriorationor wearing out in use, inclu
19、ding the effects of abrasion) arefrequently related, the relationship varies with different enduses. Different factors may be necessary in any calculation ofpredicted durability from specific abrasion data.5.3 Laboratory tests may be reliable as an indication ofrelative end use in cases where the di
20、fference in abrasionresistance of various materials is large, but they should not berelied upon where differences in laboratory test findings aresmall. In general, the results should not be relied upon forprediction of performance during actual wear life for specificend uses unless there are data sh
21、owing the specific relationshipbetween laboratory abrasion tests and actual wear in theintended end use.5.4 While there has not been extensive interlaboratorytesting prior to development of this standard, there has beensome quality control testing by manufacturers. An intralabora-tory test was condu
22、cted to initiate this test method, using asingle product. This data will be used to determine a prelimi-nary statement on precision and bias. Subsequent to approvalof this standard, a formalized interlaboratory procedure will beinitiated under the direction of a professional statistician andwill pro
23、duce a research report. Samples used in this controlledtest will be representative of end use applications.5.5 These general observations apply to most webbings thatare used in automotive, aerospace, industrial, and militaryapplications.5.6 This test method can be used for acceptance testing ofcomme
24、rcial shipments but comparisons should be made withcaution because estimates of between-laboratory precision areincomplete.5.7 If there are differences of practical significance betweenreported test results for two laboratories (or more), compara-tive tests should be performed to determine if there
25、is astatistical bias between them, using competent statistical assis-tance. As a minimum, use samples for such comparative teststhat are as homogenous as possible, drawn from the same lot ofmaterial as the samples that resulted in disparate results duringinitial testing, and randomly assigned in equ
26、al numbers to eachlaboratory. The test results from the laboratories involvedshould be compared using a statistical test for unpaired data, asa probability level chosen prior to the testing series. If bias isfound, either its cause must be found and corrected, or futuretest results must be adjusted
27、in consideration of the knownbias.6. Apparatus6.1 Webbing Abrasion TesterThe webbing abrasion testerconsists of a suitable mechanism that will provide a recipro-cating motion of the webbing over a standardized hex bar. Oneend of each specimen is attached to the mechanism and theother end passing ove
28、r a hexagonal steel rod is attached to aweight. The hexagonal rod is so fixed as to subject the webbingspecimen to abrasion on two adjacent edges as the drum movesthe specimen across the rod. One example of such a mecha-nism is a reciprocating drum as illustrated in Fig. 1.6.1.1 Mass “B” shall be 90
29、0 6 60g(2lb6 2 oz) forwebbing with breaking strengths up to 4500 N (1000 lb), 18006 60g(4lb6 2 oz) for breaking strengths of 4500 to 13 500N (1000 to 3000 lb) and 2400 6 60 g (5.2 6 2 lb) for breakingstrengths over 13 500 N (3000 lb).6.1.2 Steel hexagonal rods “C” shall be 6.35 6 0.03 mm(0.250 6 0.0
30、01 in.) when measured across opposite flat sidesand the radius shall be 0.5 6 0.2 mm (0.020 6 0.008 in.). Thesteel shall have a cold drawn finish and a Rockwell Hardnessof B-91 to B-101. The edges of the hexagonal rods shall nothave any burrs, nicks or scale.6.1.3 The mechanism “D” shall have a nomi
31、nal outsidediameter of 400 mm (16 in.) or be some mechanism able toFIG. 1 Webbing Abrasion TesterD 67702produce a reciprocating motion of at least 300 mm (12 in.) overthe hex rod with a suitable means for attaching the specimen tobe tested without damage to the specimen.6.1.4 The crank-arm “F” shall
32、 be attached to the mechanism“D” and to the driver disk “E” in such a manner that when thespecimen is attached to the mechanism, the specimen duringthe test will oscillate over the hexagonal rod the requireddistance during each stroke and at the required rate (see 10.4).6.1.5 The hexagonal rod shall
33、 be so placed that specimen“A” with the weight attached to one end and the other endpassing over the hexagonal rod and attached to the drivemechanism will form an angle of 85 6 2 “H”.6.2 Tensile Testing Machine, CRE-Type equipped with split-drum webbing clamps as described in Federal Test Method191b
34、, Method 4108.7. Sampling and Test Specimens7.1 Lot SampleTake a lot sample as directed in theapplicable material specification. In absence of such a specifi-cation randomly select five rolls or pieces to constitute the lotsample.7.2 Laboratory Sampling UnitAs a laboratory samplingunit take from eac
35、h roll or piece one piece of webbing that is2.8 m (3.0 yd) in length.7.3 Test SpecimensFrom each laboratory sampling unit,cut 2 test specimens 1.4 m (1.5 yd) in length. Mark onespecimen “A” for abraded and the other “U” for unabraded.7.3.1 When the lot or shipment consists of less than 5 rollsor pie
36、ces, randomly select 5 test specimens that represent allrolls or pieces in the lot or shipment.7.4 Ensure specimens are free of folds, creases, or wrinkles.Avoid getting oil, water, grease, and so forth, on the specimenswhen handling.8. Conditioning8.1 Condition the test specimens to moisture equili
37、brium fortesting in the standard atmosphere for testing textiles inaccordance with Practice D 1776 or, if applicable, in thespecified atmosphere in which the testing is to be performed.8.2 In the event of dispute concerning the results of teststhat may be affected by the moisture content, test speci
38、men(s)shall be preconditioned by bringing them to approximatemoisture equilibrium in the standard atmosphere for precondi-tioning textiles in accordance with Practice D 1776.9. Preparation and Calibration of Test Apparatus9.1 Ensure the test machine is on a level, sturdy surface andfree from vibrati
39、on.9.2 For hexagonal rods a manufacturers certificate of com-pliance shall be acceptable as to the requirements as describedin 6.1.2.10. Procedure10.1 Condition the “A” test specimens in the standardatmosphere for testing textiles, in accordance with Section 8.10.2 Attach the required mass (6.1.1) t
40、o one end of the testspecimen, pass the other end over the hexagonal rod and attachto the drum. The length of the test specimen(s) shall beadjusted, without altering the original length, so that the testspecimen(s) will oscillate across the hexagon rod and each endof the abraded area will be equidis
41、tant from the ends of the testspecimen(s).10.3 The edges of each new hexagonal rod shall be identi-fied as 1 through 6, and rotated after each use so that noabrading edges are used more than once. Use edge 1 and twofor one test specimen, edge 3 and 4 for a second test specimen,edges 5 and 6 for a th
42、ird test specimen, and then discard therod.10.4 Oscillate the mechanism so that the test specimen(s)are given a 300 6 25 mm (12 6 1 in.) traverse over the rod atthe rate of 1 6 .03 strokes (0.5 cycles) per second for 5000strokes (2500 cycles). One single stroke is 300 6 25 mm (126 1 in.) in one dire
43、ction only.10.5 After the machine has stopped at the predeterminednumber of cycles remove the test specimen(s) from theabrading machine.10.6 Continue as directed in 10.210.5 until all the requiredspecimens have been abraded for each laboratory samplingunit.10.7 Determine the breaking force of the ab
44、raded specimens(A) and the unabraded specimens (U) for each laboratorysampling unit in the lot to the nearest 1 % as directed inFed-Std-191, Method 4108 set as follows:10.7.1 Attach the split drum webbing clamps in the tensiletester and set the distance between them to 250 mm (10 in.)center to cente
45、r.10.7.2 Set the testing speed to 75 6 25 mm (3 6 1 in./min).11. Calculation11.1 Calculate the average breaking force for the lot of theabraded test specimens from the results of the laboratorysampling units.11.2 Calculate the average breaking force for the lot of theunabraded test specimens from th
46、e results of the laboratorysampling units.11.3 Calculate the percentage of retained breaking force tothe nearest 1 % for the lot using Eq 1:AR 5100AU(1)where:AR = abrasion resistance, %,A = average breaking force of the abraded specimens, N(lb), andU = average breaking force of the unabraded specime
47、ns,N (lb).11.3.1 When data are automatically computer processed,calculations are generally contained in the associated software.It is recommended that computer-processed data be verifiedagainst known property values and its software described in thereport.12. Report12.1 Report that the abrasion resi
48、stance was determined inaccordance with Test Method D6770. Describe the material orproduct sampled.12.2 Report the following information for the laboratorysampling unit and for the lot as applicable to a materialD 67703specification or contract order:12.2.1 Abrasion resistance, percent retained in b
49、reakingforce.12.2.2 Breaking force of abraded test specimens.12.2.3 Breaking force of unabraded test specimens.12.2.4 For computer-processed data, identify the program(software) used.13. Precision and Bias13.1 An intralaboratory test was conducted for the determi-nation of precision and bias of this test method. The results ofthe test are attached as Table 1.NOTE 1Because the intralaboratory test included less than the recom-mended five laboratories, estimates of precision data may be eitherunderestimated or overestimated to a considerable extent and should beused wit
