1、Designation: D6075 00 (Reapproved 2010)Standard Test Method forCracking Resistance of Leather1This standard is issued under the fixed designation D6075; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber 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 Department of Defense.1. Scope1.1 This test method covers the determination of the resis-
3、tance of leather to cracking when the leather is bent or foldedwith the grain (or finish) surface on the outside of the bend.Heavy leathers (for example, harness, belt, strap, bag, case, andso forth) are usually bent around a mandrel using eithermechanical resistance (for example, clamp, vise, and s
4、o forth)or by hand. Lighter leathers (for example, shoe upper, uphol-stery, garment, glove, and so forth) are usually given a sharpdouble-fold (crosswise) bend after cooling to a low tempera-ture. This test method does not apply to wet blue.1.2 The values stated in SI units are to be regarded as the
5、standard. The values given in parentheses are for informationonly.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 app
6、lica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1517 Terminology Relating to LeatherD1610 Practice for Conditioning Leather and Leather Prod-ucts for Testing3. Terminology3.1 For definitions of general leather terms used in this testmethod, refer to Ter
7、minology D1517.3.2 Definitions:3.2.1 finish crackingthe appearance of cracks (that is,ruptures) in the finish of leather which may extend through thefinish layer to the surface of the crust leather or deeper.3.2.2 grain crackingthe appearance of cracks (that is,ruptures of the grain enamel) on the g
8、rain surface of the leatherwhich may even extend deeper into the leather cross section.4. Summary of Test Method4.1 A specimen of leather is conditioned and then bent byone of three procedures. The grain (or finish) surface of thebent specimen is then examined for the appearance of anycracks or rupt
9、ures in the area around the bend.4.1.1 One bending procedure for heavier leathers involves amandrel rod, a metal bar with thickness equal to the diameterof the mandrel, and a large clamp or vise to force and hold theleather in the bent configuration around the mandrel with themetal bar placed betwee
10、n the flesh surfaces of the bent leather.4.1.2 A second bending procedure for heavier leathersinvolves bending the leather around a mandrel by hand andforcing and holding the leather so the flesh surfaces of the bentleather are in contact.4.1.3 A third bending procedure for lighter leathers involves
11、cooling the leather specimen and then creating a sharp double(crosswise) fold while the specimen remains in the coldchamber.5. Significance and Use5.1 This test method is designed to determine the crackingresistance of the grain or finish surface of leather on a pass/failbasis. This test method atte
12、mpts to replicate the conditions thatmay be encountered by leather that is bent around a buckleframe or other anchoring device, folded over in seams or welts,and so forth. The cracking resistance of leather is influenced bymany factors such as quantity, location, and type of fatliquor-ing materials;
13、 moisture content; thickness; the presence ofdefects or scar tissue, or both; the presence of processingdamages to the skin or hide tissue; finish system formulation,and so forth. This test method is useful for manufacturingcontrol in the tannery, specification acceptance, and qualitycontrol in the
14、end product manufacturing plant.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. Thistest method is a combination of three methods (that is, Methods 4011, 4021,and 7211) that were part of Federal
15、 Test Method Standard No. 311. This test methodwas developed in cooperation with the U.S. Defense Personnel Support Center,Directorate of Clothing and Textiles, Philadelphia, PA and the U.S. Army NatickResearch, Development and Engineering Center Natick, MA.Current edition approved April 1, 2010. Pu
16、blished May 2010. Originallyapproved in 1997. Last previous edition approved in 2005 as D6075 00 (2005).DOI: 10.1520/D6075-00R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
17、on, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Vise or Clamp, shall have plain (that is, smooth and notknurled or roughened) jaws not less than 7 cm
18、 (234 in.) wide.6.2 Mandrel, shall be a rod approximately 15 cm (6 in.) inlength and shall have a diameter as specified in the materialspecification.6.3 Metal Bar, shall be approximately 15 cm (6 in.) inlength, 1.9 cm (34 in.) in width, and shall have a thicknessequal to the diameter of the mandrel
19、as specified in the materialspecification.6.4 Low-temperature Chamber, shall be capable of main-taining the required temperature (usually 0C) to within 6 1Cand equipped so as to permit insertion of hands to hold andmanipulate the leather specimen within the chamber.7. Test Specimens7.1 The test spec
20、imen for bending around a mandrel shall be150 mm (6 in.) long by 25 mm (1 in.) wide. The direction ofthe long dimension relative to the backbone shall be noted.7.2 The test specimen for low-temperature double-foldingshall be 50 6 2mm(26 0.08 in.) square.7.3 All test specimens shall be free from mech
21、anical dam-age and defects.8. Conditioning8.1 Condition all specimens in accordance with PracticeD1610. Conditioning other than that prescribed shall be notedin the results.9. Procedure9.1 Determine the thickness of the specimen (in the area thatwill be bent) to the nearest 0.025 mm (0.001 in.). See
22、 TestMethod D2813.9.2 Vise- or Clamp-aided BendingBend the specimen intoa loop with the grain or finish side of the leather out. Place themandrel of the specified diameter in the loop of the specimen.Place the metal bar having a thickness equal to the diameter ofthe mandrel on top of the mandrel. Pl
23、ace the whole assemblyin the vise with the loop downward as illustrated in Fig. 1.Bend the specimen around the mandrel and against the bar byslowly closing the vise jaws until the mandrel and bar cannotbe moved by hand. Examine the grain or finish side of thespecimen for cracks in the area around th
24、e bend.9.3 Hand BendingBend the specimen slowly by handover a mandrel of the specified diameter. Make the bendthrough an angle of 180 with the grain or finish side of theleather out. Examine the grain or finish side of the specimen forcracks in the area around the bend.9.4 Low-temperature Bending:9.
25、4.1 Expose the conditioned specimen to a temperature of0 6 1C for a period of 2 h 6 5 min, and then test at thattemperature. A testing temperature different than that pre-scribed shall be noted in the reported results.9.4.2 Place the specimen in the low-temperature chamberand maintain at the require
26、d temperature for the requiredperiod of time. While remaining in the cold chamber at thespecified temperature, fold the specimen crosswise sharplyupon itself with the grain or finish surface of the leather facingout. Then remove the folded specimen from the cold chamberand examine for cracks in the
27、area around the double-foldbend.10. Report10.1 Report the following information:10.1.1 The presence or absence of any cracks in the speci-men,10.1.2 The thickness of the leather specimen,10.1.3 If appropriate, the direction of the long dimension ofthe specimen relative to the backbone,10.1.4 If a ma
28、ndrel was used, the diameter of the mandrel,and10.1.5 If a low-temperature chamber was used, the tempera-ture at which the specimen was tested.11. Precision and Bias11.1 This test method is adopted from the Federal TestMethod Standard No. 311, Methods 4011, 4021, and 7211.These methods have long bee
29、n in use and were approved forpublication before the inclusion of precision and bias state-ments was mandated. The user is cautioned to verify by the useof reference materials, if available, that the precision and bias(or reproducibility) of this test method is adequate for thecontemplated use.12. K
30、eywords12.1 cracking; cracking resistance; finish cracking; graincracking; leather; leather crackingFIG. 1 Leather Specimen Bent in ViseD6075 00 (2010)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Us
31、ers 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 at any time by the responsible technical committee and must be reviewed ever
32、y 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 comments will receive careful consideration at a meeting of theresponsible techni
33、cal 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 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
34、n, 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 ASTM website (www.astm.org/COPYRIGHT/).D6075 00 (2010)3
