scope:

All steel sheet whose bare surface is composed of Fe.

※ Bare surfaces of MG(Zn-Ni) steel sheet and organic coated steel are made not of Fe but of Zn-Ni and organic resin and no reaction takes place between their surface and ferro solution. As a consequence, their coating conditions cannot be identified with this test.

PURPOSE

This standard aims at specifying the method of checking conditions of coating on bare steel sheet surface that has passed through the pre-treatment process in the paint shop and describe specifically how to evaluate the coating condition based on presence and quantity of blue spots, which are created as a result of reaction between ferro solution and steel.