ASTM D6491-99
(Practice)Standard Practice for Evaluation of Aging Resistance of Prestressed Prepainted Metal In a Dry Heat Test
Standard Practice for Evaluation of Aging Resistance of Prestressed Prepainted Metal In a Dry Heat Test
SCOPE
1.1 This practice can be used to evaluate the resistance of a prestressed prepainted metal panel to cracking, or loss of adhesion, or both, after accelerated heat aging. Most coil coated products are formed and bent into specific shapes to produce a final product. These operations introduce stresses, which may be relieved by cracking of the coating afer aging.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation: D 6491 – 99
Standard Practice for
Evaluation of Aging Resistance of Prestressed Prepainted
Metal In a Dry Heat Test
This standard is issued under the fixed designation D 6491; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Test Specimens
1.1 This practice can be used to evaluate the resistance of a 4.1 Cut samples 75 mm (3 in.) wide (across the bend
prestressed prepainted metal panel to cracking, or loss of direction) by whatever length is necessary to make the appro-
adhesion, or both, after accelerated heat aging. Most coil priate number of bends. The direction of the bend may be
coated products are formed and bent into specific shapes to transverse or longitudinal to the “rolling direction” of the
produce a final product. These operations introduce stresses, metal—or as agreed upon between customer and vendor.
which may be relieved by cracking of the coating after aging.
5. Procedure
1.2 The values stated in SI units are to be regarded as the
5.1 Perform the fabrication at room temperature, 25 6 1°C
standard. The values given in parentheses are for information
only. (77 6 2°F). All test specimens should be equilibrated to the
same temperature before fabricating.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 5.2 Prepare three “T-bend” test specimens in accordance
with Test Method D 4145. The T-bend used should be agreed
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- upon between customer and vendor.
5.3 Examine the T-bend for cracking and tape pick-off in
bility of regulatory limitations prior to use.
accordance with Test Method D 4145 and record the results.
2. Referenced Documents
5.4 Place the formed test specimens in the 60 6 3°C (140 6
2.1 ASTM Standards: 5°F) oven for 16 h. Different times and temperatures may be
D 4145 Test Method for Coating Flexibility of Prepainted used if agreed upon between the customer and vendor.
Sheet 5.5 Remove the test specimens and allow them to cool to
room temperature.
3. Apparatus
5.6 Repeat the tape adhesion test.
3.1 Gravity or Forced Air Laboratory Oven, capable of
6. Report
maintaining a temperature of 60 6 3°C (140 6 5°F).
3.2 Bench Vise, with smooth jaws or inserts, 1
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