NBN EN 13523-7:2014

This part of EN 13523 specifies the procedure for determining the resistance to cracking of an organic coating on a metallic substrate when bent through 135° to 180°. The degree of adhesion may also be evaluated.
Both folding and mandrel methods are considered. The folding method is more often used for practical purposes but where more precise determinations are required, the mandrel method is recommended.
The cylindrical bend method may also be used for a pass/ fail decision by using an agreed mandrel.
The choice of the appropriate test method is limited by the thickness and/ or the hardness of the substrate.
The feasibility of the test depends on the type and thickness of the substrate. During the procedure, the mandrel should not deform.