DETERMINING METHOD OF PLATING FILM OF TWO-LAYER PLATED STEEL PLATE

摘要

PURPOSE:To determine the plating film of each layer with high precision from a previously obtained relational curve by measuring the intensities of fluorescent X rays at takeout angles corresponding to the 1st excitation incidence angle at which no fluorescent X rays from a steep plate blank base are detected in a two-layer plated steel plate and the 2nd excitation incidence angle at which fluorescent X rays are detected. CONSTITUTION:The intensity of fluorescent X rays E is measured at the takeout angle psi of the incidence angle phi of the 1st exciting rays (e) at which no fluorescent X rays are detected in the plated steel plate A formed by forming an Ni-Zn plating layer 2 and an Fe plating layer 3 for improving coating property on the steel plate blank base 1 and the sticking amount of FE of the layer 3 is determined by a calibration line obtained previously as to the sticking amount. Then, the X-ray intensity ratio of Ni and Zn of the layer 2 and the intensity of Fe are detected from the fluorescent X-ray intensity at the takeout angle psi corresponding to the 2nd excitation incidence angle phi at which fluorescent X rays from the base 1 are detected. The plating sticking of the layer 2 is determined from the relational curve between the X-ray intensity of Fe of the layer 3 and the plating sticking amount of the layer 3. The sticking amounts of Ni and Zn are known from said sticking amount by using the intensity ratio of Ni and Zn. Thus, the high-precision determination is performed nondestructively.