1、Designation: D4705 00 (Reapproved 2010) D4705 12Standard Test Method forStitch Tear Strength of Leather, Double Hole1This standard is issued under the fixed designation D4705; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A 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
3、 use in determining the stitch tearing resistance of leather using a double hole tear. It isparticularly applicable to lightweight leathers. This test method does not apply to wet blue.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathe
4、maticalconversions to SI units that are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and he
5、alth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1610 Practice for Conditioning Leather and Leather Products for TestingD1813 Test Method for Measuring Thickness of Leather Test SpecimensD2209 Test Method for Tensile Str
6、ength of LeatherD2813 Practice for Sampling Leather for Physical and Chemical Tests3. Significance and Use3.1 This test method is designed to measure the load required to tear leather through two holes in the test specimen. Tannersand leather buyers have found that this test gives an indication of t
7、he resistance of leather to tearing. It is of particular value inestimating the durability of leather to withstand tearing stresses encountered in the manufacture of shoes, garments, andupholstered products. The thickness of the specimen and direction of tear relative to the backbone will affect the
8、 uniformity of thetest results. This test method may not apply when the conditions of the test employed differ widely from those specified in the testmethod.4. Apparatus4.1 Testing Machine, as described in Test Method D2209.4.2 Thickness Gage, a dead weight type of thickness gage as described in Met
9、hod D1813.4.3 Steel Die, to cut test specimens (as described in 5.1).4.4 Paper Clip, #1/Premium, with wire diameter 0.041 6 0.001 in. (1.04 6 0.0254 mm).5. Sampling Test Specimen5.1 Unless otherwise specified, sample the leather according to Practice D2813.5.2 The specimen shall be a rectangle of le
10、ather 2 in. (50.8 mm) in length and 1 in. (25.4 mm) in width with two holes (564in. (1.98 mm) in diameter on one end of the specimen. The centers of the holes shall be 14 in. (6.35 mm) from the end, 14 in.(6.35 mm) apart, and located equidistant from the center line (length wise) of the specimen. Se
11、e Fig. 1.1 This test method is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.07 on Physical Properties.Current edition approved Oct. 1, 2010Sept. 1, 2012. Published November 2010 October 2012. Originally approved in 1987. Last previous e
12、dition approved in 2005 asD4705 - 00 (2005).(2010). DOI: 10.1520/D4705-00R10.10.1520/D4705-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docume
13、nt Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM rec
14、ommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 The spec
15、imen shall be cut with the long dimension perpendicular to the backbone.6. Conditioning6.1 All specimen shall be conditioned for 48 h in an atmosphere maintained at 73.4 6 3.6F (23 6 2C) and 50 6 4 % relativehumidity and tested under the conditions as described in Practice D1610.7. Procedure7.1 Dete
16、rmine the thickness of the specimen to the nearest 0.5 oz (0.20.001 in. (0.01 mm) on the long axis near one end.7.2 Bend the wire into a “U” shape, preferably by bending over a 14 in. (6.35 mm) rod, and pass the ends through the holesin the specimen so that both ends project from the flesh side of t
17、he specimen. Clamp both ends of the wire in the testing machinegrip, the jaws of which have been covered. Clamp the free end of the specimen in the other grip of the testing machine.7.3 Operate the machine at 10 6 2 in. (254 6 50.8 mm) per minminute until the specimen tears. At the instant that the
18、specimenbegins to tear, note and record the load registered by the machine.8. Report8.1 Report the following:8.1.1 Thickness to the nearest 0.5 oz (0.20.001 in. (0.01 mm) reported for each specimen or averaged and reported as thethickness of the sample.8.1.2 The tearing strength of the specimen shal
19、l be reported to the nearest 1 lb (0.45 kg).9. Precision and Bias (or Reproducibility)9.1 This test method is adopted from the procedure of the American Leather Chemists Association where it has long been inuse and where it was approved for publication before the inclusion of precision and bias stat
20、ements was mandated. The originalinterlaboratory test data is no longer available. The user is cautioned to verify by the use of reference materials, if available, thatthe precision and bias (or reproducibility) of this test method is adequate for the contemplated use.FIG. 1 Test SpecimenD4705 12210
21、. Keywords10.1 leather; stitch tear; stitch tear strength; strength; tear strength; strength tearing 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
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