1、Designation:D221100(Reapproved 2015)Standard Test Method forElongation of Leather1This standard is issued under the fixed designation D2211;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 parenth
2、eses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of the elon-gation or stretch characteristics of leather produced by a tensileload.This test method is intended for
3、use on all types of leatherand with all of the breaking load tests.This test method doesnot 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
4、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 t
5、o use.2.Referenced Documents2.1 ASTM Standards:2D1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD2209 Test Method for Tensile Strength of Leather3.Terminology3.1 Definitions:3.1.1 elongation,or stretchthe increase in length of a spanof specimen under tension.4.Significance a
6、nd Use4.1 The elongation measurement may be made at anydesignated load and is expressed as a percentage of the originaldistance between the jaws or between bench marks of theunstretched specimen.The speed of the machine is important.Speeds under or more than 10 6 2 in./min(4.2 6 0.8 mm/s)will give v
7、ariables in the results,thus affecting the reproduc-ibility of the method.The direction relative to the backboneand the width of the test specimen determines the magnitude ofthe elongation.This test method is excellent for development,control,specification acceptance,and service evaluation ofleather
8、.This test method may not apply when the conditions ofthe test employed differ widely from those specified in the testmethod.5.Apparatus5.1 Testing Machine,as described in Test Method D2209.5.2 Dividers,having legs at least 4 in.(102 mm)long and anadjustable screw arrangement for fixing the distance
9、 betweenthem.5.3 Steel Scale,graduated to read in 0.02 in.(0.5 mm).6.Test Specimen6.1 The specimen shall be dumbbell in shape when the testis made with the tension test.It shall be cut from the test unitof leather by means of a die as shown in Fig.1 of Test MethodD2209.The direction of the long axis
10、 relative to the backboneshall be noted.6.2 The specimen for narrow strap,welting,lace,and roundbelting leathers shall be a piece of leather uniform in width and6 in.(152 mm)long.6.3 The specimen for the grab method of determiningbreaking load shall be 6 in.(152 mm)long and 3 in.(76 mm)wide.7.Condit
11、ioning7.1 All specimens shall be conditioned as prescribed inPractice D1610.Conditioning other than as prescribed shall benoted in the results.8.Procedure8.1 Mount the specimen symmetrically with the jaws sepa-rated a distance of 4 in.(102 mm).8.2 Operate the machine so that the movable grip travels
12、 ata speed of 10 6 2 in./min(4.2 6 0.8 mm/s).8.3 Follow the distance between the jaws or the differencebetween bench marks with the dividers until the load at which1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.07 on P
13、hysical Properties.Thistest method was developed in cooperation with the American Leather ChemistsAssn.Current edition approved May 1,2015.Published July 2015.Originally approvedin 1963.Last previous edition approved in 2010 as D2211 00(2010).DOI:10.1520/D2211-00R15.2For referenced ASTM standards,vi
14、sit 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.Unit
15、ed States1 the elongation is desired has been reached.Take all measure-ments between the inner edges of the jaws or between the inneredges of the bench marks.Measure the distance between thepoints of the legs of the dividers to the nearest 0.02 in.(0.5mm).An autographic attachment is preferred for d
16、eterminingthe elongation.With this arrangement the elongation may beobtained from the chart at any desired load.8.4 If the elongation is determined as a span shorter than thedistance between the jaws,use a 2-in.(51-mm)bench markeror its equivalent,as shown in Fig.1.Mark the specimen overthe span at which it is desired to make the elongationmeasurement.NOTE1In general,results obtained for elongation over a 2-in.(51-mm)span marked by the bench marker on the narrow section of thetension test specim