1、Designation: D6491 09 (Reapproved 2016)Standard Practice forEvaluation of Aging Resistance of Prestressed PrepaintedMetal In a Dry Heat Test1This standard is issued under the fixed designation D6491; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice can be used to evaluate the resistance of aprestressed prepainted metal pan
3、el to cracking, or loss ofadhesion, or both, after accelerated heat aging. Most coilcoated products are formed and bent into specific shapes toproduce a final product. These operations introduce stresses,which may be relieved by cracking of the coating after aging.1.2 The values stated in SI units a
4、re to be regarded as thestandard. 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 practic
5、es and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4145 Test Method for Coating Flexibility of PrepaintedSheet3. Apparatus3.1 Gravity or Forced Air Laboratory Oven, capable ofmaintaining a temperature of 60 6 3C (140 6 5F).3.2 Bench
6、 Vise, with smooth jaws or inserts, 130 mm (5 in.)permanently mounted on a work table or bench, or alternativeequipment capable of making the appropriate bends.3.3 Bending Dies or Test Shims, (optional).3.4 10X magnifier, (optional).3.5 Adhesive Tape.4. Test Specimens4.1 Cut samples 75 mm (3 in.) wi
7、de (across the benddirection) by whatever length is necessary to make the appro-priate number of bends. The direction of the bend may betransverse or longitudinal to the “rolling direction” of themetalor as agreed upon between customer and vendor.5. Procedure5.1 Perform the fabrication at room tempe
8、rature, 25 6 1C(77 6 2F). All test specimens should be equilibrated to thesame temperature before fabricating. Different fabricationtemperatures may be used, when needed, to meet customer orvendor requirements, or both.5.2 Prepare three “T-bend” test specimens in accordancewith Test Method D4145. Th
9、e T-bend used should be agreedupon between customer and vendor.5.3 Examine the T-bend for cracking and tape pick-off inaccordance with Test Method D4145 and record the results.5.4 Place the formed test specimens in the 60 6 3C (140 65F) oven for 16 h. Different times and temperatures may beused if a
10、greed upon between the customer and vendor.5.5 Remove the test specimens and allow them to cool toroom temperature.5.6 Repeat the tape adhesion test.6. Report6.1 Report the following information:6.1.1 Reexamine the test specimens for cracking and tapepick-off.6.2 The degree of cracking and tape pick
11、-off allowed shouldbe agreed upon between the customer and the vendor. Reportsubstrate, coating system, production or preparation date, thetape used, cracking and tape pick-off noted before heat aging,the heat aging time and temperature and cracking, and tapepick-off noted after heat aging.7. Keywor
12、ds7.1 aging; coil; cracking; dry heat; fabrication; flexibility;heat aging; prepaint; pick-off; stresses; t-bend1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coat
13、ed Metal.Current edition approved Dec. 1, 2016. Published December 2016. Originallyapproved in 1999. Last previous edition approved in 2009 as D6491 09. DOI:10.1520/D6491-09R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. F
14、or 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. United StatesThis international standard was developed in accordance with internatio
15、nally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1ASTM International takes no position respecting the v
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18、uarters. Your comments 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 stan
19、dard 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). 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:/ 09 (2016)2
