Micom offers ASTM D522 – Mandrel Bend Test – as part of its surface coating test services. ASTM D522 – Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings 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.
Mandrel Bend Test – Use 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
For coating elongation rating: cold-rolled steel strip 0.8 mm (1⁄32 in.) (22 gage) thick.
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: