ASTM_D_4704_-_13.pdf

Designation:D470413Standard Test Method forTearing Strength,Tongue Tear of Leather1This standard is issued under the fixed designation D4704;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year 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 U.S.Department of Defense.1.Scope1.1 This test method is intended for determining the tearingstrength of leather by measuring the force required to tear aspecimen cut perpendicular to the surface.This test methoddoes not apply to wet blue.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 information 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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD1813 Test Method for Measuring Thickness of LeatherTest SpecimensD2209 Test Method for Tensile Strength of LeatherD2813 Practice for Sampling Leather for Physical andChemical Tests3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 tongue tear strengththe load required to tear theleather between two tongues formed by splitting the leatherperpendicular to its surface.4.Significance and Use4.1 Knowledge of the strength of the sample can be adetermining factor for the end use of the product.5.Apparatus5.1 Testing Machine,as described in Test Method D2209.5.2 Thickness Gage,a dead weight type of thickness gage asdescribed in Test Method D1813.5.3 Steel Die,to cut test specimens.6.Sampling and Test Specimens6.1 Unless otherwise specified,sample the leather accordingto Practice D2813.6.2 The specimen shall be a rectangular piece of leather,1 4 in.(25.4 101.6 mm)by the full thickness of the unit.Itshall have a316in.(4.76 mm)hole located on the long axis 1in.(25.4 mm)from one end and shall be split along its axisfrom the hole to the other end to form two tongues.Thedirection of the long axis of the specimen relative to thebackbone shall be noted.See Fig.1.7.Conditioning7.1 All specimens shall be conditioned and tested in anatmosphere as described in Practice D1610.8.Procedure8.1 Determine the thickness of the specimen to the nearest0.001 in.(0.01 mm)on the long axis between the hole and theunsplit end of the specimen.The gage foot shall be adjacent to,but shall not overlap,the hole.8.2 Clamp one of the tongues on the specimen in each of thetesting grips so that the long axis of the tongue is in thedirection of the motion of the movable grip.The faces of thegrips shall be approximately 2 in.(50.8 mm)from the commonbase of the tongues(from the hole).8.3 Operate the machine at 10 6 2 in.(254 6 50.8 mm)perminute until the specimen starts to tear.At the instant of theinitial tear,note and record the load registered by the machine.9.Report9.1 The thickness measurement of all specimens tested shallbe averaged to the nearest 0.001 in.(0.01 mm)and reported asthe thickness of the sample.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.07 on Physical PropertiesCurrent edition approved May 1,2013.Published May 2013.Originallyapproved in 1987.Last previous edition approved in 2012 as D4704 12.DOI:10.1520/D4704-13.2For 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 International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 9.2 The load required to tear the specimens shall be aver-aged to the nearest pound and reported as the tongue tearstrength of the sample.9.3 The direction of the long axis of the specimen relative tothe backbone shall be reported.10.Precision and Bias(or Reproducibility)10.1 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 was mandated.Theoriginal inter-laboratory test data is no longer available.Theuser is cautioned to verify by the use of reference materials,ifavailable,that the precision and bias(or reproducibility)of thistest method is adequate for the contemplated use.11.Keywords11.1 leather;tear strength;tearing strength;tongue tear;tongue tear strength;strengthASTM International takes no position