ASTM D522-93a(2008)
(Test Method)Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings
Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings
SIGNIFICANCE AND USE
Coatings attached to substrates are elongated when the substrates are bent during the manufacture of articles or when the articles are abused in service. These test methods have been useful in rating attached coatings for their ability to resist cracking when elongated. They have been useful in evaluating the flexibility of coatings on flexible substrates.
SCOPE
1.1 These test methods cover the determination of the resistance to cracking (flexibility) of attached organic coatings on substrates of sheet metal or rubber-type materials.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D522 −93a(Reapproved 2008)
Standard Test Methods for
Mandrel Bend Test of Attached Organic Coatings
This standard is issued under the fixed designation D522; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 mandrel and the resistance to cracking of the coating is
determined. In Test Method A the coated panels are bent over
1.1 These test methods cover the determination of the
aconicalmandrel.InTestMethodBthecoatedpanelsarebent
resistance to cracking (flexibility) of attached organic coatings
over cylindrical mandrels of various diameters.
on substrates of sheet metal or rubber-type materials.
1.2 The values stated in SI units are to be regarded as the
4. Significance and Use
standard. The values given in parentheses are for information
4.1 Coatings attached to substrates are elongated when the
only.
substrates are bent during the manufacture of articles or when
1.3 This standard does not purport to address all of the
thearticlesareabusedinservice.Thesetestmethodshavebeen
safety concerns, if any, associated with its use. It is the
useful in rating attached coatings for their ability to resist
responsibility of the user of this standard to establish appro-
cracking when elongated. They have been useful in evaluating
priate safety and health practices and determine the applica-
the flexibility of coatings on flexible substrates.
bility of regulatory limitations prior to use.
5. Test Specimen
2. Referenced Documents
2 5.1 Substrates:
2.1 ASTM Standards:
5.1.1 Ifthepurposeofthetestistodeterminethepercentof
D823Practices for Producing Films of Uniform Thickness
elongation of the coating material, the substrate shall be
of Paint, Varnish, and Related Products on Test Panels
cold-rolled steel strip 0.8 mm ( ⁄32 in.) (22 gage) thick.
D1005Test Method for Measurement of Dry-Film Thick-
5.1.2 If the purpose of the test is to rate the coated material
ness of Organic Coatings Using Micrometers
for resistance to cracking, the substrate may be any type of
D1186Test Methods for Nondestructive Measurement of
sheet metal or rubber-type material (for example, steel,
Dry Film Thickness of Nonmagnetic CoatingsApplied to
3 aluminum, tinplate, or synthetic rubber). The thickness of the
a Ferrous Base (Withdrawn 2006)
sheetmetalmaybelessthan0.8mm( ⁄32in.)andthethickness
D1400TestMethodforNondestructiveMeasurementofDry
of the rubber-type materials may be as great as 13 mm ( ⁄2 in.).
Film Thickness of Nonconductive Coatings Applied to a
3 5.1.3 The recommended panel size is 100 mm (4 in.) in
Nonferrous Metal Base (Withdrawn 2006)
widthand150mm(6in.)inlength.Themaximumsizethatthe
conical mandrel can accommodate is 115 mm (4 ⁄2 in.) wide
3. Summary of Test Method
and 190 mm (7 ⁄2 in.) long.
3.1 The coating materials under test are applied at uniform
5.1.4 The surface preparation of the substrate shall be
thickness to panels of sheet metal or rubber-type materials.
agreed upon between the purchaser and the seller. Prior to the
After drying or curing the coated panels are bent over a
application of the coating, round slightly the edges of metal
panels to remove burrs in order to eliminate anomalous edge
These test methods are under the jurisdiction of ASTM Committee D01 on
effects.
Paint and Related Coatings, Materials, and Applications and are the direct
NOTE 1—If elongations are to be determined for coatings applied to
responsibility of Subcommittee D01.23 on Physical Properties of Applied Paint
Films. substrates other than 0.8 mm ( ⁄32 in.) thick cold-rolled steel, they must be
Current edition approved Feb. 15, 2008. Published February 2008. Originally measured with a special mandrel jig as described in Appendix X1.2.
approved in 1939. Last previous edition approved in 2001 as D522–93a(2001).
5.2 Coated Panels:
DOI: 10.1520/D0522-93AR08.
5.2.1 Apply uniform coatings of the materials under test to
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
thesubstratesinaccordancewithPracticesD823andairdryor
Standards volume information, refer to the standard’s Document Summary page on
bake under conditions mutually agreeable to the purchaser and
the ASTM website.
the seller. If percent elongation is to be measured, a minimum
The last approved version of this historical standard is referenced on
www.astm.org. thickness of 1.0 mil is required on 0.8 mm ( ⁄32 in.) thick
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D522 − 93a (2008)
cold-rolled steel. Perform a minimum of three determinations 8.2 Move the lever through about 180° at uniform velocity
of coating thickness on each of the specimens in accordance tobendthespecimenapproximately135°.Ifthepurposeofthe
with Test Methods D1005, D1186,or D1400. test is to measure elongation, the bend should be 15 s. To
5.2.2 From precoated sheets cut at least three specimens of determine crack resistance under more simulated use condi-
the size given in 5.1.3. Use only plane (flat) sheets and round tions, the bend time should be about 1 s unless an alternative
the edges of the panels slightly as in 5.1.4.The coating surface time is agreed upon between the producer and the user.
shall be free of oil and other foreign matter that might increase
8.3 Examine the bent surface of the specimen immediately
the flexibility of the coating or interfere with the observation
with the unaided eye for cracking. Having determined and
for cracking. Measure the film thickness as in 5.2.1.
suitably marked the end of the crack farthest from the small
endofthemandrel,whichshallbeconsideredastheendpoint,
6. Conditioning and Number of Tests
bringthedrawbartothestartingpositionandremovethepanel
6.1 Condition the test specimens for at least 24 h at 23
from the mandrel. Measure the distance from the farthest end
62°C(73.5 63.5°F)and50 65%relativehumidity,andtest
of the crack to the small end of the mandrel. This distance is
inthesameenvironmentorimmediatelyonremovaltherefrom
used to compute the elongation. The mandrel diameter at
unless otherwise specified by the purchaser and seller.
which cracking ceased is taken as the resistance to cracking
value.
6.2 Test at least three replicate specimens in Test MethodA
and at least two replicate specimens in Test Method B at each
NOTE 2—In some cases, the measured distance is used as a measure of
mandrel diameter of interest.
crack resistance.
TEST METHOD A—CONICAL MANDREL TEST
9. Calculation
7. Apparatus 9.1 When required, determine the elongation of the finish
from the plotted curve in Fig. 2. This curve represents the
7.1 Conical Mandrel Tester, consisting of a metal cone, a
relationshipbetweenthepercentelongationandthediameterof
rotating panel-bending arm, and panel clamps, all mounted on
the conical mandrel for a 1.0 mil coating thickness. The
a metal base as illustrated in Fig. 1.
relationbetweenthedistancealongtheconicalmandrelandthe
7.1.1 Cone, smooth steel, 8 in. (200 mm) in length, with a
corresponding diameter has also been plotted on this curve.
diameter of 3 mm ( ⁄8 in.) at one end and a diameter of 38 mm
(1 ⁄2 in.) at the other end. 9.2 Adjust the percent elongation value obtained from Fig.
2 for coating thickness by adding the correction obtained from
8. Procedure
Fig. 3.
8.1 With the operating lever of the apparatus in a horizontal
NOTE 3—Example—Suppose visual examination of the finish on the
position, slip the test spe
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