ASTM D522

Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings

ASTM D522 is a standard test method for mandrel bend test of attached organic coatings. It is used to qualify the coating resistance to cracking, upon bending, once they were applied and cured on sheet metal or on other flexible materials. Micom offers ASTM D522 as part of its surface coating test services.

Uses and Factors to Be Considered

Fully cured coated panels are bent over a mandrel and the resistance to cracking of the coating is determined. In Test Method A the coated panels are bent over a conical mandrel. In Test Method B the coated panels are bent over cylindrical mandrels of various diameters.

Coatings on panels are elongated when the panels are bent upon manufacturing or when abused in service. This elongation, if the coating/curing process is not adequate can lead to cracking causing problems ranging from poor appearance to premature corrosion of the panel substrate.  ASTM D522 is used in rating the coatings for their ability to resist cracking when this happens.

Typical Experimental Parameters for ASTM D522 Mandrel Testing

• Number of specimens/product: method A: 3, method B: 2
• Substrate thickness:
  • For coating elongation rating: cold-rolled steel strip 0.8 mm (1⁄32 in.) (22 gauge) thick.
    or
  • For rating coated material: sheet metal less than 0.8 mm (1⁄32 in.) or rubber-type materials less than 13 mm (1⁄2 in.).
• Specimen dimensions: 4” X 6”
• Conditioning and testing Temperature: 23 ± 2 °C
• Conditioning and testing relative humidity: 50 ± 5%
• Other related test methods:

When testing as per ASTM D522, additional procedures are often used to evaluate coatings.  For a complete list of coating test services, we invite you to read more on Coating testing and Accelerated Aging.

If you have any other questions about the ASTM D522 test or if you would like to speak to a testing professional at Micom Laboratories to discuss a custom test for your specific product, we invite you to contact us today. It will be our pleasure to talk to you and help you with the ASTM D522 test.

The following video shows how the ASTM D522 Standard Test Method for Mandrel Bend Test of Attached Organic Coatings is applied to a finished piece of metal to evaluate its coating resistance to cracking.