PURPOSE: To judge highly the degree of the stain caused in handling the steel plate by applying onto the surface of the steel plate the artificial fingerprint liquid prepared by adding fatty acid to a sweat constituent.
CONSTITUTION: The artifical fingerprint liquid is prepared by adding about 1W 10wt% of fatty acid such as lauric acid to a water solution containing the sweat constituents such as NaCl, lactic acid, urea, etc. A fixed quantity of this artificial fingerprint liquid is applied onto the surface of the steel plate subjected to the surface processing by a method of dripping, transfer or the like. By inspecting the state of the stain on the surface of the steel plate thus treated, the degree of the stain caused in actual handling can be judged, and thereby a high level of quality control of products becomes possible.
SAKAMOTO YASUHEI
TANDA TOSHIKUNI
YAMATO KOUJI
TANAMI JIYUNICHIROU
