Patent ID: 8673641
Filing Date: 2014-03-18
Classification: G01B,G01N

Abstract:
1. An on-line detection method to determine chromium-free coating film thickness on the surface of strip steel, the method comprising: (a) selecting a first and a second water-soluble chemical substance which contain elements P, Ca, Ti, Ba or Sr and do not react with a chromium-free coating liquid; (b) adding the two water-soluble chemical substances selected from step (a) into the chromium-free coating liquid and agitating them to be homogeneous, (c) fabricating a reference sample of the coating film on the surface of strip steel; (d) obtaining a correction function by using a ray emitted by an off-line film thickness detection instrument to excite the two water-soluble chemical substances so as to obtain a characteristic spectrum of the two water-soluble chemical substances where the correction function is obtained by: (e) adding the second water-soluble chemical substance having a weak characteristic spectrum into a chromium-free coating liquid, and using a ray emitted by an on-line coating film thickness instrument to excite the substance on the surface of strip steel to obtain the measured film thickness; and (f) using the correction function and measured film thickness of step (e) to obtain a thickness correction value, whereby the chromium-free coating film thickness on the surface of strip steel is obtained from the measured film thickness and thickness correction value.