1、Designation: D2211 00 (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
2、parentheses 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 i
3、ntended for 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 informatio
4、n 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 li
5、mitations prior to 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 tens
6、ion.4. Significance and 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
7、 6 0.8 mm/s)will give variables 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
8、service evaluation ofleather. 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 a
9、rrangement for fixing the distance 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 Met
10、hodD2209. The direction of the long axis 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
11、in. (152 mm) long and 3 in. (76 mm)wide.7. Conditioning7.1 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
12、Operate the machine so that the movable grip travels 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
13、the direct responsibility of Subcommittee D31.07 on Physical 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
14、). DOI:10.1520/D2211-00R15.2For 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
15、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1the 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 t
16、he nearest 0.02 in. (0.5mm). An autographic attachment is preferred for determiningthe 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
17、 markeror its equivalent, as shown in Fig. 1. Mark the specimen overthe span at which it is desired to make the elongationmeasurement.NOTE 1In general, results obtained for elongation over a 2-in.(51-mm) span marked by the bench marker on the narrow section of thetension test specimen will be greate
18、r than that obtained by determining theaverage elongation over the entire span between the jaws.8.5 If an autographic recorder is used, read the elongation tothe nearest 0.1 in. (2.5 mm).9. Calculation9.1 Calculate the elongation to the nearest 0.1 % of theoriginal distance over the span as follows:
19、Elongation, % 5D22 D1!/D1#3100 (1)where:D1= span of the original unstretched specimen, in. (mm),andD2= span of the stretched specimen, in. (mm), when therequired load has been applied.10. Report10.1 The report shall include the following:10.1.1 Percentage elongation reported for each specimen oraver
20、age and reported as the elongation of the sample, and10.1.2 Direction of the long axis of the specimen relative tothe backbone.11. Precision and Bias11.1 The following criteria may be used to judge theacceptability of the results if at least 15 units have been tested:11.1.1 One Operator, Duplicate S
21、pecimens, Same Skin orSame UnitResults by the same operator on duplicate adjacentspecimens in a skin taken from the official sampling position orfrom the same unit in another form should not be consideredsuspect unless the coefficient of variations exceeds:Shoe upper 9 %CalfskinA7%Upholstery 10 %Gar
22、ment 8 %Laces (Note 2) 14 %Welting (Note 3) 17 %A3 1 oz, 0.0468 0.0156 in. (1.189 0.396 mm).NOTE 2Lace samples were taken at random from the bundles offinished laces. The location on side and direction of testing is unknown sothe comparison should be between and within bundles.NOTE 3Welting samples
23、were taken at random from the finishedwelting. The location on the side and direction of testing is unknown, sothe comparisons should be between and within hanks.11.1.2 Two Laboratories, Duplicate Specimens, Same Skinor Same UnitResults submitted on leather of the type listedin 11.1.1 by each of two
24、 laboratories on duplicate adjacentspecimens in a skin taken from the official sampling position orfrom a unit in a different form should not be considered suspectunless the averages of the two results differ by more than 5 %.(See Note 4, Note 5, and Note 6).NOTE 4The reproducibility reported in 11.
25、1.2 is based on dataobtained at two laboratories, each with a different type of testing machineand a different operator. One machine is a load-cell type and the other apendulum type. The results show very close correlation between labora-tories.NOTE 5The results are based on tests on 30 sides of lea
26、ther and do notapply to findings and cut parts except for laces and welting.NOTE 6The precision data for between skins are not given because theresults were based on different skins of several production lots. Thevariables in leather for between skins will give higher variation of theMetric Equivale
27、ntsin.(mm)0.002(0.05)0.003(0.08)38(9.5)34(19)1(25.4)1.997(50.72)2.003(50.88)FIG. 1 Bench MarkerD2211 00 (2015)2results, but this factor should not affect the precision of the method.12. Keywords12.1 elongation; leather; stretchASTM International takes no position respecting the validity of any paten
28、t 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 responsibility.This standard is subject to revision a
29、t 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 International Headquarters. Your commen
30、ts 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 shown below.This standard is copyrighted
31、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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 00 (2015)3
