METHOD AND ADJUSTING COMPONENT OF COATING FILM OF CHROMIUM-FREE COATED STEEL PLATE

摘要

PROBLEM TO BE SOLVED: To provide a practical technique capable of quantitatively and quickly determining the optimum amount of a chromium-free pigment for providing excellent corrosion resistance for a coated steel plate. SOLUTION: The elution amount of an anti-rust pigment contained in a coated steel plate is quantitatively and quickly estimated by measuring the conductivity of an eluent obtained by eluting the anti-rust pigment to pure water and the correlation of the value of the conductivity and the corrosion resistance of the coated steel and the range of the conductivity in which a high corrosion resistance is given to the coated steel are investigated and then the proper compounding ratio of the pigment is calculated from such a range of the conductivity to adjust the components of the coating.