ASTM D2794-93(2010)
(Test Method)Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)
Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)
SIGNIFICANCE AND USE
Coatings attached to substrates are subjected to damaging impacts during the manufacture of articles and their use in service. In its use over many years, this test method for impact resistance has been found to be useful in predicting the performance of organic coatings for their ability to resist cracking caused by impacts.
SCOPE
1.1 This test method covers a procedure for rapidly deforming by impact a coating film and its substrate and for evaluating the effect of such deformation.
1.2 This test method should be restricted to testing in only one laboratory when numerical values are used because of the poor reproducibility of the method. Interlaboratory agreement is improved when ranking is used in place of numerical values.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 This standard does not purport to address 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2794 − 93 (Reapproved 2010)
Standard Test Method for
Resistance of Organic Coatings to the Effects of Rapid
Deformation (Impact)
This standard is issued under the fixed designation D2794; 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 (´) 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. Scope 3. Terminology
1.1 This test method covers a procedure for rapidly deform- 3.1 Definitions of Terms Specific to This Standard:
ingbyimpactacoatingfilmanditssubstrateandforevaluating 3.1.1 impact resistance, of a coating, n—the number of
the effect of such deformation.
inch-pounds (kilogram-metres) required to produce cracking in
the deformed coating.
1.2 This test method should be restricted to testing in only
one laboratory when numerical values are used because of the
4. Summary of Test Method
poor reproducibility of the method. Interlaboratory agreement
is improved when ranking is used in place of numerical values.
4.1 The organic coatings under test are applied to suitable
thin metal panels. After the coatings have cured, a standard
1.3 The values stated in inch-pound units are to be regarded
weight is dropped a distance so as to strike an indenter that
as standard. The values given in parentheses are mathematical
deforms the coating and the substrate. The indentation can be
conversions to SI units that are provided for information only
either an intrusion or an extrusion. By gradually increasing the
and are not considered standard.
distance the weight drops, the point at which failure usually
1.4 This standard does not purport to address the safety
occurs can be determined. Films generally fail by cracking,
concerns, if any, associated with its use. It is the responsibility
which is made more visible by the use of a magnifier, by the
of the user of this standard to establish appropriate safety and
application of a copper sulfate (CuSO ) solution on steel, or by
health practices and determine the applicability of regulatory
the use of a pin hole detector.
limitations prior to use.
5. Significance and Use
2. Referenced Documents
5.1 Coatings attached to substrates are subjected to damag-
2.1 ASTM Standards:
ing impacts during the manufacture of articles and their use in
D609 Practice for Preparation of Cold-Rolled Steel Panels
service. In its use over many years, this test method for impact
for Testing Paint, Varnish, Conversion Coatings, and
resistance has been found to be useful in predicting the
Related Coating Products
performance of organic coatings for their ability to resist
D823 Practices for Producing Films of Uniform Thickness
cracking caused by impacts.
of Paint, Varnish, and Related Products on Test Panels
D1186 Test Methods for Nondestructive Measurement of
6. Apparatus
Dry Film Thickness of Nonmagnetic Coatings Applied to
6.1 Tester, consisting of a vertical tube to guide a cylindrical
a Ferrous Base (Withdrawn 2006)
weight that is dropped on a punch resting on the test panel.
6.1.1 Guide Tube, 24 to 48 in. (0.6 to 1.2 m) long mounted
vertically in a base plate. A slot is cut lengthwise on one side
This test method is under the jurisdiction of ASTM Committee D01 on Paint
of the tube to act as a guide for a cylindrical weight that fits
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
inside the tube. Graduations are marked in inch-pounds along
Current edition approved Dec. 1, 2010. Published December 2010. Originally
the slot. The base is constructed so that a thin flat panel can be
approved in 1969. Last previous edition approved in 2004 as D2794 – 93 (2004).
inserted at 2 in. (50 mm) below the tube.
DOI: 10.1520/D2794-93R10.
6.1.2 Weight, metal cylinder, made to fit inside the guide
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
tube.Apin is fitted into one side of the weight to act as a guide
Standards volume information, refer to the standard’s Document Summary page on
by riding in the slot of the tube and to serve as a handle by
the ASTM website.
which the weight can be raised and released and serve as the
The last approved version of this historical standard is referenced on
www.astm.org. indicator of inch-pounds (kilogram-metres).
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D2794 − 93 (2010)
6.2 Indenter—A steel punch with a hemispherical head 10.3 Examine the impacted areas for cracking by one of the
having a diameter of either 0.500 in. (12.7 mm) or 0.625 in. following methods:
(15.9 mm). The head rests on the test panel and the punch is 10.3.1 Use a magnifier to examine the area for cracks.
held vertically by a guide ring. 10.3.2 Hold a white flannel-type cloth saturated with the
acidified copper sulfate (CuSO ) solution (7.1) over the im-
6.3 Panel Support—A steel fixture with a 0.64-in. (16.3-
pacted areas for at least 15 min. Remove the cloth and examine
mm) diameter cylindrical hole centered under the indenter for
both the test areas and cloth for evidence of copper deposition
supporting the test panel.
or iron-rust staining respectively.
6.4 Magnifier.
NOTE 3—The copper sulfate solution will not perform prope
...
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