1、Designation: D 2208 00 (Reapproved 2005)Standard Test Method forBreaking Strength of Leather by the Grab Method1This standard is issued under the fixed designation D 2208; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 covers the determi
3、nation of the break-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 test
4、ed by Test Method D 2209. 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 parenthe
5、ses are forinformation 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
6、prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1517 Terminology Relating to LeatherD 1610 Practice for Conditioning Leather and LeatherProducts for TestingD 1813 Test Method for Measuring Thickness of LeatherTest SpecimensD 2209 Test Method for Tensile Strength of LeatherD 2211 Test Metho
7、d for Elongation of Leather3. Terminology3.1 For definitions of leather terms used in this standard,refer to Terminology D 1517.4. Summary of Test Method4.1 The leather specimen is clamped in the test machine asdescribed in Test Method D 2209. The force required to rupturethe leather at a jaw separa
8、tion of 10 6 2 in./min 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, n
9、arrow strap, welt, lace and round belt leathers aswell as others that cannot be accurately tested by Test MethodD 2209.6. Apparatus6.1 Testing Machine, as described in Test Method D 2209.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 mea
10、sure 1 by 112 (25.4 by38 mm) or more for testing specimens wider than the jaws only.6.2 Thickness GageA dead-mass type of thickness gageas described in Test Method D 1813.6.3 Steel Scale, graduated to read in 0.02 in. (0.5 mm).7. Test Specimen7.1 For testing specimens wider than the jaws, the specim
11、enfor 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 leatherssha
12、ll be a piece of leather 6 in. (152 mm) long.8. Conditioning8.1 All samples shall be conditioned for 48 h in standardatmospheric conditioning and tested under these conditions asdescribed in Practice D 1610.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct
13、 responsibility of D31.05 on Upholstery. This test method wasdeveloped in cooperation with the American Leather Chemists Assn. (StandardsMethod E 161965).Current edition approved Sept. 1, 2005. Published September 2005. Originallyapproved in 1963 as as D 220863T. Last previous edition approved in 20
14、00 as D220800.2For 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.1Copyright ASTM International, 100 Barr Harbor
15、Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.9. Procedure9.1 For Testing Specimens Wider than the Jaws:9.1.1 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.
16、2 The distance between the grips at the start of the testshall be 3 618 in. (76 6 3.2 mm).9.1.3 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 clamplight
17、ly. Distribute the material of the specimen uniformly andhang flat between the jaws before tightly clamping the speci-men.9.1.5 Determine the elongation of the specimen in accor-dance with Test Method D 2211.9.1.6 Operate the machine so that the movable clamp travelsat a uniform speed of 10 6 2 in./
18、min (254 6 50 mm/min) whenrunning free.9.1.7 Record the load required to rupture the specimen 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 Spe
19、cimens Cut from Narrow Strips:9.2.1 Measure the thickness of a flat specimen or thediameter 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 t
20、he direction of the applied force.9.2.3 The distance between the grips at the start of the testshall be 3 618 in. (76 6 3.2 mm).9.2.4 Determine the elongation of the specimen in accor-dance with Test Method D 2211.9.2.5 Operate the machine so that the movable clamp travelsat a uniform speed of 10 6
21、2 in./mm (254 6 50 mm/min) whenrunning free.9.2.6 Record the load required to rupture the specimen 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
22、 the sample, and10.1.2 Breaking strength to the nearest 1 lbf (or 1 N),reported for each specimen 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 teste
23、d:11.1.1 One Operator, Duplicate Specimens, Same SkinResults by the same operator on duplicate 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 %Specime
24、ns Narrower than JawsLaces (Note 3)27Welting (Note 4 4NOTE 3Lace samples are taken at 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
25、thefinished welting. The location of side and direction of testing is unknown,so the comparison 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 adjacentspeci
26、mens from the same skin taken from the official samplingposition should not be considered 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
27、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 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 s
28、kins are not given becausethe results were based on different skins of several production 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; strength
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32、ee on Standards, at the address shown below.This standard is copyrighted 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).D 2208 00 (2005)2
