ASTM D522-93a

Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings

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.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.23 - Physical Properties of Applied Paint Films

Relations

• Replaced By: ASTM D522-93a(2001) - Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM F1178-11(2022) - Standard Specification for Performance of Enameling System, Baking, Metal Joiner Work and Furniture
• Effective Date: 01-Jan-2001
• Referred By: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D7270-07(2021) - Standard Guide for Environmental and Performance Verification of Factory-Applied Liquid Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D5146-10(2019) - Standard Guide to Testing Solvent-Borne Architectural Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D2485-22 - Standard Test Methods for Evaluating Coatings For High Temperature Service
• Effective Date: 01-Jan-2001
• Referred By: ASTM D3322-23 - Standard Practice for Testing Primers and Primer Surfacers Over Preformed Metal
• Effective Date: 01-Jan-2001
• Referred By: ASTM D5324-16(2022) - Standard Guide for Testing Water-Borne Architectural Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D333-01(2021) - Standard Guide for Clear and Pigmented Lacquers
• Effective Date: 01-Jan-2001
• Referred By: ASTM D2454-23 - Standard Practice for Determining the Effect of Overbaking on Organic Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D6763-16(2022) - Standard Guide for Testing Exterior Wood Stains and Clear Water Repellents
• Effective Date: 01-Jan-2001
• Referred By: ASTM D3794-22 - Standard Guide for Testing Coil Coatings
• Effective Date: 01-Jan-2001
• Referred By: ASTM D6905-20 - Standard Practice for Impact Flexibility of Organic Coatings
• Effective Date: 01-Jan-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 522 – 93a
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Mandrel Bend Test of Attached Organic Coatings
This standard is issued under the fixed designation D 522; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope the flexibility of coatings on flexible substrates.
1.1 These test methods cover the determination of the
5. Test Specimen
resistance to cracking (flexibility) of attached organic coatings
5.1 Substrates:
on substrates of sheet metal or rubber-type materials.
5.1.1 If the purpose of the test is to determine the percent of
1.2 This standard does not purport to address all of the
elongation of the coating material, the substrate shall be
safety problems, if any, associated with its use. It is the
cold-rolled steel strip ⁄32 in. (0.8 mm) (22 gage) thick.
responsibility of the user of this standard to establish appro-
5.1.2 If the purpose of the test is to rate the coated material
priate safety and health practices and determine the applica-
for resistance to cracking, the substrate may be any type of
bility of regulatory limitations prior to use.
sheet metal or rubber-type material (for example, steel, alumi-
2. Referenced Documents num, tinplate, or synthetic rubber). The thickness of the sheet
metal may be less than ⁄32 in. (0.8 mm) and the thickness of the
2.1 ASTM Standards:
rubber-type materials may be as great as ⁄2 in. (13 mm).
D 823 Practices for Producing Films of Uniform Thickness
5.1.3 The recommended panel size is 4 in. (100 mm) in
of Paint, Varnish, and Related Products on Test Panels
width and 6 in. (150 mm) in length. The maximum size that the
D 1005 Test Methods for Measurement of Dry-Film Thick-
conical mandrel can accommodate is 4 ⁄2 in. (115 mm) wide
ness of Organic Coatings Using Micrometers
and 7 ⁄2 in. (190 mm) long.
D 1186 Test Methods for Nondestructive Measurement of
5.1.4 The surface preparation of the substrate shall be
Dry Film Thickness of Nonmagnetic Coatings Applied to
2 agreed upon between the purchaser and the seller. Prior to the
a Ferrous Base
application of the coating, round slightly the edges of metal
D 1400 Test Method for Nondestructive Measurement of
panels to remove burrs in order to eliminate anomalous edge
Dry Film Thickness of Nonconductive Coatings Applied to
effects.
a Nonferrous Metal Base
NOTE 1—If elongations are to be determined for coatings applied to
3. Summary of Test Method
substrates other than ⁄32 in. (0.8 mm) thick cold-rolled steel, they must be
measured with a special mandrel jig as described in Appendix X1.2.
3.1 The coating materials under test are applied at uniform
thickness to panels of sheet metal or rubber-type materials.
5.2 Coated Panels:
After drying or curing the coated panels are bent over a
5.2.1 Apply uniform coatings of the materials under test to
mandrel and the resistance to cracking of the coating is
the substrates in accordance with Practices D 823 and air dry or
determined. In Test Method A the coated panels are bent over
bake under conditions mutually agreeable to the purchaser and
a conical mandrel. In Test Method B the coated panels are bent
the seller. If percent elongation is to be measured, a minimum
over cylindrical mandrels of various diameters.
thickness of 1.0 mil is required on ⁄32 in. (0.8 mm) thick
cold-rolled steel. Perform a minimum of three determinations
4. Significance and Use
of coating thickness on each of the specimens in accordance
4.1 Coatings attached to substrates are elongated when the
with Test Methods D 1005, D 1186, or D 1400.
substrates are bent during the manufacture of articles or when
5.2.2 From precoated sheets cut at least three specimens of
the articles are abused in service. These test methods have been
the size given in 5.1.3. Use only plane (flat) sheets and round
useful in rating attached coatings for their ability to resist
the edges of the panels slightly as in 5.1.4. The coating surface
cracking when elongated. They have been useful in evaluating
shall be free of oil and other foreign matter that might increase
the flexibility of the coating or interfere with the observation
1 for cracking. Measure the film thickness as in 5.2.1.
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint
and Related Coatings, Materials, and Applications and is the direct responsibility of
6. Conditioning and Number of Tests
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Sept. 15, 1993. Published November 1993. Originally
6.1 Condition the test specimens for at least 24 h at 73.5 6
published as D 522 – 39. Last previous edition D 522 – 93.
3.5°F (23 6 2°C) and 50 6 5 % relative humidity, and test in
Annual Book of ASTM Standards, Vol 06.01.
D 522
the same environment or immediately on removal therefrom end of the mandrel, which shall be considered as the end point,
unless otherwise specified by the purchaser and seller. bring the drawbar to the starting position and remove the panel
6.2 Test at least three replicate specimens in Test Method A from the mandrel. Measure the distance from the farthest end
and at least two replicate specimens in Test Method B at each of the crack to the small end of the mandrel. This distance is
mandrel diameter of interest. used to compute the elongation. The mandrel diameter at
which cracking ceased is taken as the resistance to cracking
TEST METHOD A—CONICAL MANDREL TEST
value.
7. Apparatus
NOTE 2—In some cases, the measured distance is used as a measure of
crack resistance.
7.1 Conical Mandrel Tester , consisting of a metal cone, a
rotating panel-bending arm, and panel clamps, all mounted on
9. Calculation
a metal base as illustrated in Fig. 1.
7.1.1 Cone, smooth steel, 8 in. (200 mm) in length, with a 9.1 When required, determine the elongation of the finish
1 1
from the plotted curve in Fig. 2. This curve represents the
diameter of ⁄8 in. (3 mm) at one end and a diameter of 1 ⁄2 in.
(38 mm) at the other end. relationship between the percent elongation and the diameter of
the conical mandrel for a 1.0 mil coating thickness. The
8. Procedure
relation between the distance along the conical mandrel and the
8.1 With the operating lever of the apparatus in a horizontal corresponding diameter has also been plotted on this curve.
position, slip the test specimen between the mandrel and the
9.2 Adjust the percent elongation value obtained from Fig.
drawbar with the finish side towards the drawbar. Rigidly
2 for coating thickness by adding the correction obtained from
clamp the specimen in a vertical position adjacent to the
Fig. 3.
mandrel by placing the long edge behind the clamping bar in
NOTE 3—Example—Suppose visual examination of the finish on the
such a manner that the panel is always set up to the narrow end
bent cold-rolled steel specimens ⁄32 in. (0.8 mm) in thickness shows that
of the mandrel. Slip two sheets of No. 1 brown kraft wrapping
the end of the first crack in the coating is at a distance of 3 in. (75 mm)
paper, substrate 30, thoroughly lubricated on each side with
from the small end of the cone. From Fig. 2 determine the percent
talc, between the specimen and the drawbar and hold in
elongation of the film from the measured crack distance, in this
...