1、Designation: D2208 16Standard Test Method forBreaking Strength of Leather by the Grab Method1This standard is issued under the fixed designation D2208; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber 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 covers the determination of the br
3、eak-ing strength of leather by the grab method. It is intended for useon light, soft leathers; boarded, sueded, or embossed leatherstested on a specimen in the form of a rectangle piece; narrowstrap, welt, lace, and round belt leathers; or other leathers thatcannot be accurately tested by Test Metho
4、d D2209. This testmethod does not apply to wet blue.1.2 The test method is not recommended for breaking loadsover 500 lbf (2200 N) because of slippage of the specimen inthe jaws.1.3 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinform
5、ation only.1.4 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. R
6、eferenced Documents2.1 ASTM Standards:2D1517 Terminology Relating to LeatherD1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD1813 Test Method for Measuring Thickness of LeatherTest SpecimensD2209 Test Method for Tensile Strength of LeatherD2211 Test Method for Elongation of
7、Leather3. Terminology3.1 For definitions of leather terms used in this standard,refer to Terminology D1517.4. Summary of Test Method4.1 The leather specimen is clamped in the test machine asdescribed in Test Method D2209. The force required to rupturethe leather at a jaw separation of 10 6 2 in./min
8、 is measured,along with the percent elongation at rupture.5. Significance and Use5.1 The measurement of the strength of leather is oftennecessary in order to determine its suitability for its intendedapplication. This test method is recommended for use on light,soft leathers, narrow strap, welt, lac
9、e and round belt leathers aswell as others that cannot be accurately tested by Test MethodD2209.6. Apparatus6.1 Testing Machine, as described in Test Method D2209.NOTE 1The face of one jaw of each clamp shall measure 1 by 1 in.(25.4 by 25.4 mm) and that of the other shall measure 1 by 112 (25.4 by38
10、 mm) or more for testing specimens wider than the jaws only.6.2 Thickness GageAdead-mass type of thickness gage asdescribed in Test Method D1813.6.3 Steel Scale, graduated to read in 0.02 in. (0.5 mm).7. Sampling, Test Specimens, and Test Units7.1 For testing specimens wider than the jaws, the speci
11、menfor wide, flat leathers shall be a small piece of leather 6 in. (152mm) long and 3 in. (76 mm) wide. The direction of the longdimension relative to the backbone shall be noted.7.2 For testing specimens cut from narrow strip, the speci-men for narrow strap, welting, lace, and round belt leatherssh
12、all be a piece of leather 6 in. (152 mm) long.8. Conditioning8.1 Conditions as described in Practice D1610.9. Procedure9.1 For Testing Specimens Wider than the Jaws:1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of D31.05 on Upholstery. T
13、his test method wasdeveloped in cooperation with the American Leather Chemists Assn. (StandardsMethod E161965).Current edition approved Sept. 1, 2016. Published October 2016. Originallyapproved in 1963. Last previous edition approved in 2010 as D220800 (2016).DOI: 10.1520/D2208-16.2For referenced AS
14、TM 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 Conshoho
15、cken, PA 19428-2959. United States19.1.1 Measure the thickness of the specimen to the nearest0.001 in. (0.025 mm) in three places: at the center and on thelong axis 1 in. (25.4 mm) each side of the center.9.1.2 The distance between the grips at the start of the testshall be 3 618 in. (76 6 3.2 mm).9
16、.1.3 The face of one jaw of each clamp shall measure 1 by1 in. (25.4 by 25.4 mm).9.1.4 Place the specimen in the testing machine with its longaxis parallel to the direction of the applied force, and clamplightly. Distribute the material of the specimen uniformly andhang flat between the jaws before
17、tightly clamping the speci-men.9.1.5 Determine the elongation of the specimen in accor-dance with Test Method D2211.9.1.6 Operate the machine so that the movable clamp travelsat a uniform speed of 10 6 2 in./min (254 6 50 mm/min) whenrunning free.9.1.7 Record the load required to rupture the specime
18、n asthe breaking strength.NOTE 2In a test of this type, many of the specimens will rupture at thejaws of the testing machines. The load should be recorded regardless ofthe place of rupture.9.2 For Testing Specimens Cut from Narrow Strips:9.2.1 Measure the thickness of a flat specimen or thediameter
19、of a round specimen to the nearest 0.001 in. (0.025mm) in three places: at the center and 1 in. (25.4 mm) each sideof the center.9.2.2 Place the specimen in the testing machine with its longaxis parallel to the direction of the applied force.9.2.3 The distance between the grips at the start of the t
20、estshall be 3 618 in. (76 6 3.2 mm).9.2.4 Determine the elongation of the specimen in accor-dance with Test Method D2211.9.2.5 Operate the machine so that the movable clamp travelsat a uniform speed of 10 6 2 in./mm (254 6 50 mm/min) whenrunning free.9.2.6 Record the load required to rupture the spe
21、cimen asthe breaking strength.10. Report10.1 The report shall include the following:10.1.1 Thickness to the nearest 0.001 in. (0.025 mm),reported for each specimen or averaged and reported as thethickness of the sample, and10.1.2 Breaking strength to the nearest 1 lbf (or 1 N),reported for each spec
22、imen or averaged and reported as thebreaking strength of the sample.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 Specimens, Same SkinResults by the same operator on duplicat
23、e adjacent specimensin a skin taken from the official sampling position should not beconsidered suspect unless the coefficient of variation exceeds:Specimens Wider than JawsUpholstery 16 %Garment 11 %Specimens Narrower than JawsLaces (Note 3) 27 %Welting (Note 4) 24 %NOTE 3Lace samples are taken at
24、random from the bundles offinished laces. The location of die and direction of testing is unknown, sothe comparisons should be between and within bundles.NOTE 4Welting samples are taken at random from the hanks of thefinished welting. The location of side and direction of testing is unknown,so the c
25、omparison should be between and within hanks.11.1.2 Two Laboratories, Duplicate Specimens, SameSkinResults submitted on leathers of the type mentioned in11.1.1 by each of two laboratories on duplicate adjacentspecimens from the same skin taken from the official samplingposition should not be conside
26、red suspect unless the average ofthe two results differs by more than 5 %.NOTE 5The reproducibility reported in 11.1.2 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. Th
27、e results show very close correlation between labora-tories.NOTE 6The results in Section 11 are based on tests on 30 sides ofleather and do not apply to findings and cut parts.NOTE 7The precision data for between skins are not given because theresults were based on different skins of several product
28、ion lots. Thevariables in leather for between skins will give higher variation of theresults, but this factor should not affect the precision of the test method.12. Keywords12.1 breaking strength; leather; strengthASTM International takes no position respecting the validity of any patent rights asse
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