Cupping test method and acceptance criteria

       The cupping test method is to place a thin plate sample sprayed according to certain process parameters on the 33mm blank holder of the cupping test machine (the coating side is facing down), and then use a steel ball with a diameter of 20mm to press it under a certain pressure. A test method for evaluating the bonding strength of the coating according to the coating condition at the convex place after unloading a pit.



The size of the cupping sample is 75mmx44mm and 55mmx60mm, and the thickness is A3 steel plate of 1.3mm~1.5mm. When shearing the sample, it is necessary to ensure that the edge of the sample is flat and free of burrs, and that the sample is not subject to hammering and other cold work hardening, and the sample should not be heat treated.

The hard and brittle alloy spray coating has a thickness of 0.05mm~0.10mm; the alloy spray coating with good plasticity has a thickness of 0.10mm~0.15mm.

The determination of the thickness of the spray coating is extremely important. If it is less than or greater than the above requirements, there will be phenomena such as no cracking of the coating or all cracking and falling off, which often leads to wrong judgments.

Cupping test acceptance criteria:

The hard and brittle alloy spray coating has a depth of 5mm, and the alloy spray coating with good plasticity has a depth of 7.6mm.

After the cupping test is performed in practice, check the raised part of the coating according to the following criteria:

    Qualified status----the coating has no cracks or slight cracks, but the coating does not fall off;

The minimum qualified state - the coating is cracked but not peeled off;

Unqualified state----the coating cracks and falls off.