1、Designation: D4831 00 (Reapproved 2010)Standard Test Method forBuckle Tear Strength of Leather1This standard is issued under the fixed designation D4831; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method is intended for use on all types ofle
3、ather to determine the load required to tear a leather strapfastened in a buckle. This test method does not apply to wetblue.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for informat
4、ion onlyand are not considered 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 practices and determine the applica-bility of regulatory
5、limitations prior to use.2. Significance and Use2.1 This test method is designed to measure the loadrequired to tear a leather strap fastened in a buckle. Tanners andleather buyers have found that this test gives an indication ofthe resistance of leather to tearing.2.2 This test method should be sui
6、table for specificationacceptance, design purposes, manufacturing control, develop-ment, and research. The thickness of the specimen and direc-tion of tear relative to the backbone will affect the uniformityof the test results. This test method may not apply when theconditions of the test employed d
7、iffer widely from thosespecified in this test method.3. Apparatus3.1 Gage, spring-type, for measuring thickness of units,graduated in 0.5 oz or 0.1 mm having a flat pressure foot 0.4 60.025 in. (10.2 6 0.6 mm) in diameter and a flat anvil 0.4 60.025 in. in diameter. The spring shall exert a force of
8、 1 lbf(4.45 N) on the foot when the gage reads 2 oz and 2 lbf (8.9 N)when the gage reads 12 oz.3.2 Steel Punch, which will make a316 in. (4.8 mm)diameter hole.3.3 Harness Buckle, 1.25 in. (4.7 mm) with a 0.175 60.005-in. (4.4 6 0.1-mm) diameter tongue. It shall be attachedto a strong strap, 1.25 in.
9、 wide and at least 5 in. (127 mm) long.The strap shall be equipped with a keeper located approxi-mately 0.75 in. (19 mm) from the buckle.3.4 Testing Machine, power-driven. The applied load shallbe indicated on a dial, scale, or chart. The load indicator shallrecord or indicate the maximum load at th
10、e time of rupture ofthe specimen. The machine shall be equipped with a set ofgrips for clamping the specimens. The faces of the grips shouldbe knurled or otherwise roughened to prevent slipping of thespecimen. The gripping surfaces shall be at least 1 by 112 in.(25.4 by 38 mm). The grips shall be mo
11、unted with the longerdimension perpendicular to the direction of the application ofthe load. The speed of the power-activated grip shall be auniform speed of 10 6 2 in. (254 6 50 mm)/min when runningfree. The error of the machine up to a load of 50 lbf (222 N)shall not exceed 2 %; at loads of more t
12、han 50 lbf the errorshall not exceed 1 %.4. Sampling, Test Specimens, and Test Units4.1 The specimen shall be a piece of leather 1 by 8 in. (25by 200 mm). Note the direction of the long axis relative to thebackbone.5. Procedure5.1 Punch a316-in. (4.76-mm) hole on the long axis of thespecimen 3 in. (
13、76.2 mm) from one end.5.2 Measure the thickness of the specimen to the nearest 0.5oz (0.2 mm) of the long axis between the hole and the shortend. Place the gage foot adjacent to, but not overlapping, thehole.5.3 Fit the specimen in the buckle with the tongue of thebuckle in the hole and the short en
14、d of the specimen under thekeeper. Clamp the other end of the specimen in one of the1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable LeatherCurrent edition approved April 1, 2010. Published May 2010. Orig
15、inallyapproved in 1988. Last previous edition approved in 2005 as D4831 00 (2005).DOI: 10.1520/D4831-00R10.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.testing machine grips so that the hole is approximately 3 in. (76mm) from the
16、grip. Clamp the free end of the buckle strap inthe other grip. Operate the machine at 10 6 2 in. (254 6 50mm)/min until the specimen begins to tear. At that instant, noteand record the load registered by the machine.6. Report6.1 The report shall include the following:6.1.1 The thickness of the sampl
17、e which shall be the averageof the thickness measurements of the specimens, reported tothe nearest 0.5 oz (0.2 mm),6.1.2 The buckle tear strength of the sample which shall bethe average of the loads for the specimens, reported to thenearest 1 lb (0.45 kg), and6.1.3 The direction of the long axis rel
18、ative to the backbone.7. Precision and Bias7.1 This test method is adopted from the procedures of theAmerican Leather ChemistsAssociation where it has long beenin use and where it was approved for publication before theinclusion of precision and bias statements were mandated. Theoriginal interlabora
19、tory test data is no longer available. Theuser is cautioned to verify by the use of reference material, ifavailable, that the precision and bias of this test method isadequate for the contemplated use.8. Keywords8.1 buckle tear; leather; strength; tear; tear strengthASTM International takes no posit
20、ion respecting the validity of any patent rights asserted in connection with any 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 responsibilit
21、y.This standard is subject to revision at any time by the responsible technical committee 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
22、 International Headquarters. Your comments will receive careful consideration at 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 s
23、hown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4831 00 (2010)2
