1、Designation: D 4831 00 (Reapproved 2005)Standard Test Method forBuckle Tear Strength of Leather1This standard is issued under the fixed designation D 4831; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 o
3、fleather to determine the load required to tear a leather strapfastened in a buckle. This test method does not apply to wetblue.1.2 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
4、appro-priate safety and health practices and determine the applica-bility of regulatory 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
5、 an indication ofthe resistance of leather to tearing.2.2 This test method should be suitable 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 th
6、e test results. This test method may not apply when theconditions of the test employed differ 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
7、 diameter and a flat anvil 0.4 60.025 in. in diameter. The spring shall exert a force of 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
8、.005-in. (4.4 6 0.1-mm) diameter tongue. It shall be attachedto a strong strap, 1.25 in. 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
9、dial, scale, or chart. The load indicator shallrecord or indicate the maximum load at the 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. Th
10、e gripping surfaces shall be at least 1 by 112 in.(25.4 by 38 mm). The grips shall be mounted 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 err
11、or of the machine up to a load of 50 lbf (222 N)shall not exceed 2 %; at loads of more than 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 thebackbo
12、ne.5. Procedure5.1 Punch a316-in. (4.76-mm) hole on the long axis of thespecimen 3 in. (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
13、Fit the specimen in the buckle with the tongue of thebuckle in the hole and the short end of the specimen under thekeeper. Clamp the other end of the specimen in one of thetesting machine grips so that the hole is approximately 3 in. (76mm) from the grip. Clamp the free end of the buckle strap inthe
14、 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:1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is
15、 the direct responsibility of Subcommittee D31.01 on Vegetable LeatherCurrent edition approved Sept. 1, 2005. Published September 2005. Originallyapproved in 1988. Last previous edition approved in 2000 as D 4831 00.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
16、, PA 19428-2959, United States.6.1.1 The thickness of the sample 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 thenear
17、est 1 lb (0.45 kg), and6.1.3 The direction of the long axis relative 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 preci
18、sion and bias statements were mandated. Theoriginal interlaboratory 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;
19、 strength; tear; tear strengthASTM International takes no position 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 in
20、fringement of such rights, are entirely their own responsibility.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 stan
21、dard or for additional standardsand should be addressed to ASTM 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 v
22、iews known to the ASTM Committee on Standards, at the address shown 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).D 4831 00 (2005)2
