Mandrel bend test

The mandrel bend test enables assessment of the resistance of a coating to cracking and/or flaking from a metallic substrate.

This involves coated and scored sheets of metal being bent over a conical mandrel with the aid of a test device. The coating at the thin end of the cone is stretched or compressed the most. The size of the bend radius in which no cracks or flaking is to be seen is an indication of how well a coating adheres or the extent to which it can be stretched or compressed.

The mandrel bend test is not the only important tensile test for sheet coatings. The Erichsen cupping test is also often used. The major difference between the two tests: In the mandrel bend test sheets are bent rapidly in one dimension, in the Erichsen cupping test slowly in two dimensions.