JPH0335149A - Method and instrument for measuring plating deposition and plating film composition of plated steel sheet - Google Patents

Abstract

PURPOSE:To make on-line measurement of a plating deposition and plating film compsn. by taking out the X-rays of the wavelength of large absorption by a plating and irradiating a plated steel sheet to be measured by using quadratic targets. CONSTITUTION:The theoretical calculation equation for the intensity or intensity ratio at the prescribed light receiving angle of the fluorescent X-rays of the element desired to be analyzed obtd. from the plated steel sheet in the case of irradiating steel sheet with the characteristic X-rays generated by irradiation of two kinds of the quadratic targets with the X-rays at respectively prescribed incident angles is determined in a stage (a). The conversion coefft. to convert the actually measured value under the same conditions as for the stage (a) to a theoretically calculated value is determined by using a standard sample of a known plating deposition and plating film compsn. in a stage (b). The fluoresent X-ray intensity, etc., obtd. from the plated steel sheet to be measured having an unknown plating deposition and plating film compsn. are measured under the same conditions and are converted to the theoretical intensity, etc., by using the conversion coefft. in a stage (c). The plating deposition and film compsn. which are most approximated to the theoretical intensity, etc., converted from the theoretical intensity, etc., obtd. from the theoretical calculation equation are determined as the plating deposition and plating film compsm. of the plated steel sheet to be measured in a stage (d).

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for measuring the coating weight and coating composition of a plated steel sheet by online measuring the coating weight and coating composition of a plated steel plate to be measured, and the method thereof. The present invention relates to a measuring device, and in particular to a method and device for measuring the amount of plating deposited on a plated steel sheet and the composition of the plating film, which is effective for analysis when the metal/sodium coating contains the same components as the underlying metal.

[Conventional technology]

Fluorescent X-ray analysis is used to measure the coating amount and coating composition of this type of plated steel sheet to be measured. This fluorescent X-ray analysis method irradiates the plated steel plate to be measured with X-rays, then measures the fluorescent X-rays emitted in proportion to the plating thickness, and compares this measured value with a calibration curve. Therefore, it is possible to measure the amount of plating and the composition of the plating film online for those whose plating film does not contain a base metal, such as a Zn-plated steel sheet or a Zn-Ni-plated steel sheet.

However, in recent years, Zn-Fe alloy plated steel sheets have attracted attention for their excellent properties such as corrosion resistance and workability. It is difficult to distinguish it from the fluorescent X-rays caused by Fe, which is the base metal, and therefore it is not only difficult to correlate the fluorescent X-ray intensity with the amount of plating deposited and the composition of the plating film, but it is also difficult to analyze it online. I can't.

Therefore, the following two analysis methods have been proposed as methods for improving the above-mentioned problems.

One of them had multiple wavelengths on a Zn-Fe alloy plated steel plate. After irradiating so-called white X-rays, the first measurement angle is such that the fluorescent X-rays from the base metal of the plated steel plate are virtually undetectable from the point of view of the X-ray penetration depth, and the fluorescent X-rays from the base metal are detected. This is an online analysis method that measures the fluorescence X-ray intensity of each series by arranging detectors for the second 1#1 constant angle and ζ, and determines the amount of plating and the composition of the plating film based on the constant values on both sides. (Unexamined Japanese Patent Publication No. 58-
223047).

The other method is to use the absorption by the coating on a Zn-Fe alloy plated steel plate to detect the diffraction of α-Fe in the base metal (X!). Find the plated tffi from I, and further calculate the Zn in the plated film.
- This is a method for determining the coating composition from the diffraction X-ray intensity of one or more phases selected from the Fe alloy phase and the η phase (Japanese Patent Laid-Open No.
0-169553).

[Problem to be solved by the invention]

However, as mentioned above, of the two analysis methods, the former fluorescent X-ray analysis method using two measurement angles uses white XvA as the incident X-ray, so the following problems have been pointed out. There is.

■-1 High energy X in white X-rays! ! ! has the property that the penetration depth is deep due to low attenuation in the coating of the plated steel sheet, and for this reason, the first measurement angle at which fluorescent X-rays from the underlying metal cannot be detected is extremely limited to within 5 degrees. It needs to be at a small angle.

As a result, fluctuations in the measurement distance and measurement angle due to vertical movement of the plated steel plate surface, that is, flapping, are likely to occur.
There is a problem that measurement accuracy decreases.

■-2 In addition, the amount of plating deposited and the composition of the plating film are calculated by comparing the measured strength obtained by actually irradiating the plated steel plate with X-rays and the theoretical strength obtained by applying it in advance to a well-known theoretical strength calculation formula. However, when calculating the theoretical intensity, there is a problem in that the measurement accuracy decreases because it is affected by spectral fluctuations of incident X-rays due to changes in the X-ray tube over time.

■-3 In addition, when calculating the analytical value by comparing the above-mentioned measured intensity with the theoretical intensity calculated from the well-known theoretical intensity calculation formula, the calculation time is longer because wavelength integration is required when calculating the theoretical intensity. It is undeniable that the measurement time will increase.

■-4 Furthermore, there is a method of using a calibration curve to avoid the problem pointed out in ■-2 above, but this method requires 20 to 30 types of standard samples to create a model that takes matrix effects into consideration. However, this is a very complicated analysis method.

On the other hand, in the latter analysis method using diffraction X-rays,
The diffraction X-ray intensity of α-Fe in the base metal depends not only on the coating amount but also on the different textures and plating film compositions caused by the steel type and thickness of the steel sheet, the manufacturing conditions of the plated steel sheet, etc., and therefore the measurement accuracy is affected. There is a problem in terms of

■-2 On the other hand, the diffraction X-ray intensity of the alloy phase differs depending on the plating conditions, and the structure and composition of the alloy differ between hot-dip plated materials and electroplated materials, so sufficient measurement accuracy cannot be obtained in this case as well. .

The present invention has been made in view of the above circumstances, and it is possible to measure the amount of plating and the composition of the plating film online while reducing the influence of fluctuations on the surface of the plated steel sheet, and also to improve the accuracy of analysis and shorten the analysis time. It is an object of the present invention to provide a method for measuring the amount of plating deposit and the composition of the plating film on a plated steel sheet, which can reliably measure the amount of plating deposit and the composition of the plating film using a small number of standard samples.

In addition, the purpose of the measuring device, which is another invention, is to
The object of the present invention is to accurately measure the amount of plating coating and the composition of the plating film online using a simple configuration.

[Means and effects for solving the problem] Therefore, in order to solve the above problem, the invention corresponding to claim 1 irradiates two types of secondary targets with X-rays generated from an X-ray generator, and The characteristic X generated from the secondary target of
A theoretical formula for the intensity or intensity ratio of the target element to be analyzed generated from the plated steel plate when the beam is irradiated onto the plated steel plate at a predetermined angle of incidence is determined in advance, and the amount of plating deposited and the intensity ratio are determined in advance. The fluorescent X-ray intensity or intensity ratio is actually measured using a standard sample whose plating film composition is known under the same conditions as those used to obtain the theoretical calculation formula, and the actual value is converted to the theoretical calculation value based on this actual measurement value and the theoretical calculation formula. The conversion coefficient for converting to is determined in advance.

After determining the theoretical calculation formula and conversion coefficient as described above, use the same measurement conditions as those used to determine the theoretical calculation formula for a plated steel sheet to be measured whose coating weight and coating film composition are unknown. The fluorescent X-ray intensity or intensity ratio obtained from the plated steel plate to be measured is measured, and then this fluorescent X-ray intensity or intensity ratio is converted into a theoretical intensity or intensity ratio using a conversion coefficient. Then, the plated steel plate to be measured is determined using the plating coating amount and the plating film composition, which are parameters in the theoretical calculation formula, to bring the theoretical strength or strength ratio obtained from the theoretical calculation formula closest to the converted theoretical strength or strength ratio. The amount of plating deposited and the composition of the plating film are as follows.

Next, the invention corresponding to claim 2 irradiates two types of secondary targets with X-rays generated from an X-ray generator, and transmits characteristic X-rays generated from each secondary target at a predetermined angle of incidence. Fluorescence Xl of the series of analysis target elements generated from the plated steel plate when irradiated with the plated steel plate! A calibration curve of the intensity or intensity ratio at a predetermined acceptance angle is determined using the plating amount and the plating film composition as parameters, and then the calibration curve is calculated for the plated steel sheet to be measured whose plating amount and plating film composition are unknown. The fluorescent X-ray intensity or intensity ratio obtained from the plated steel sheet to be measured is measured under the same measurement conditions as those used to obtain the calibration curve. Further, the measured plating is determined using the plating coating amount and plating film composition, which are parameters in the calibration curve, which bring the fluorescent X-ray intensity or intensity ratio obtained from the calibration curve closest to the measured fluorescent X-ray intensity or intensity ratio. The amount of plating deposited on the steel plate and the composition of the plating film.

Next, the invention corresponding to claim 3 includes an X-ray generator that generates X-rays, and a method for irradiating the X-rays generated from the X-ray generator to make the characteristic X-rays generated to be incident on a plated steel plate to be measured. A reflective secondary target part that emits X-rays, and XI! A slit system that determines a pass line and projects the light onto the plated steel plate to be measured at a predetermined incident angle and receives the light at a predetermined reception angle, and a series fluorescence intensity of the target element to be analyzed generated from the plated steel plate to be measured at a predetermined value. Two detectors that measure angles, a means for storing theoretical calculation formulas for the theoretical intensities or intensities and ratios that should be obtained with these measurement systems, and a means for storing the actually measured fluorescent X-ray intensities or intensity ratios as the theoretical intensities. or a means for converting it into an intensity ratio, and a means for determining the plating coating amount and plating film composition that minimize the difference between the converted theoretical strength or strength ratio and the theoretical strength or strength ratio obtained from the theoretical calculation formula. It is prepared.

Therefore, by taking the above measures, the characteristic X-rays obtained by irradiating the secondary target with X-rays generated from the X-ray generator are incident on the plated steel plate to be measured at a predetermined incident angle, As a result, the series fluorescent X-ray intensity of the analysis target element generated from the plated steel plate to be measured is detected at a predetermined acceptance angle using two detectors.

Then, the fluorescent X-ray intensity or intensity ratio measured by these two detectors is converted to the theoretical intensity or intensity ratio, and the plated H
The theoretical strength or strength ratio is calculated using a theoretical calculation formula using m and the plating film composition as variable parameters, and this calculated value is used to obtain the plating adhesion amount and plating film composition of the plated steel sheet to be measured from the parameters based on the converted values.

Further, the invention corresponding to claim 4 is a configuration in which a transmission type secondary target is provided in place of the reflective type secondary target section described in the invention corresponding to claim 3.

Furthermore, the invention corresponding to claim 5 includes a measurement system consisting of an X-ray generator, a reflective secondary target section, a slit system, two detectors, etc., as well as the theoretical intensity or a storage means for storing a calibration curve of intensity ratio;
This apparatus is equipped with means for determining the amount of plating deposited and the plating film composition that minimizes the difference between the actually measured fluorescent X-ray intensity or intensity ratio and the fluorescent X-ray intensity or intensity ratio obtained from a calibration curve.

In this apparatus, the amount of plating deposited and the plating film composition of the plated steel sheet to be measured are measured by using a calibration curve instead of the theoretical calculation formula and by using almost the same signal processing means as described above.

Furthermore, the invention corresponding to claim 6 provides a transmissive type secondary target section in place of the reflective secondary target section of the invention corresponding to claim 5.
This configuration includes a second target section.

〔Example〕

Hereinafter, prior to a detailed explanation of the present invention, it is assumed that the present invention is constructed with a measurement system that satisfies the following conditions in order to be suitable for on-line measurement.

(b) Incident X-rays are collected using a commercially available X-ray tube to generate sufficient fluorescent X-rays.
Obtain line strength.

(b) Measurement angles such as the X-ray incident angle and the fluorescent

Further, the intensity of fluorescent X-rays generated from the plated steel plate is measured using a radiation detector, preferably using a semiconductor detector.

Next, an example of a method for measuring the coating amount and coating film composition (Fe%) of a Zn--Fe alloy plated steel sheet will be described.

That is, this measurement method uses the characteristic X@1. .

■2 is the incident angle φ1. The intensity of the Feka wire and Znka generated from the plated steel plate 11 to be measured at this time is irradiated with φ2.
The intensity of the line is determined by the acceptance angle ψ1. Measure at ψ2. Therefore, the Feka line intensity and Znka line intensity measured under the conditions of this measurement angle (φ1.ψ, ) are respectively I'P#J I'za
and F measured under the conditions of measurement angle (φ2゜ψ2)
eka line intensity.

Znka line intensity is 12P @ l I2Z respectively
m, and X t ”I'P-/I'Z.

Perform the calculation (Sl): In this case, the theoretical value is the fluorescence X-ray intensity obtained when measuring under the same incident X-ray and geometric conditions as the measurement conditions, calculated using a theoretical formula using the coating amount of the plated steel sheet and the coating film composition as parameters. Based on this value, the values corresponding to X t and X 2 are determined.Actual measured values may differ from these theoretical intensities due to the sensitivity characteristics of the detector, the influence of the slit system, etc. .

Therefore, in the method of the present invention, the measured values Xl and X2 are converted into theoretical values Y, Y2 using the following conversion formula (S2).

Y, -al x1 + bl Yz = a2 X2 + b2 In addition, in the above formula, a l + a 2 r b
l + b2 is a conversion coefficient, which is obtained by actually measuring the fluorescent X-ray intensity or intensity ratio under the same conditions as those used to obtain the theoretical calculation formula using a standard sample whose plating coating amount and plating film composition are known in advance. It is determined by converting the actual measured value of the strength into a theoretical intensity or intensity ratio using the above-mentioned theoretical calculation formula. In other words, the above formula holds between Y, Y2, which is calculated using the theoretical calculation formula using the plating deposition amount and plating film composition of the standard sample, and X,, I2, which is calculated from the actually measured fluorescent X-ray intensity. As such, the conversion coefficient al is determined by regression analysis or the like.

a2. bl and b2 are determined in advance.

In this way, we used a theoretical calculation formula and adopted a method of configuring the differences with the actual measurement system using standard samples. A relational expression of intensity or intensity ratio can be obtained.

Next, if the theoretical values Ys and Yz are found in S2,
Subsequently, using the parameter Pk (k-1) in which the plating adhesion amount and Fe% are varied, Y, , Y2 corresponding to the above Yl, Y2 are determined from the existing fluorescent X-ray intensity calculation formula (
93. S4). After that, the process moves to S5, where the calculation (Y+ Yl ) 2+ (Y2 +Y2 ) 2 is performed, and the same calculation is performed by changing the parameter Pk (S6.S4.S5), and these calculation values are Determine the value of the parameter when the calculated value is the smallest in ψ (S7), and use this determined parameter value to select H1 with plating.
By setting t and Fe%, the plated steel plate 1 to be measured
This results in a plating coating weight and a plating film composition of 1.

Next, analysis results obtained using the above measurement method will be specifically explained. Now, the measurement conditions for Xl are incident X-ray 11 and measurement angle (φ1.ψ1), and the measurement conditions for I2 are incident X-ray I2 and measurement angle (φ2.ψ2).

In addition, in order to satisfy the condition (a) mentioned above, a tungsten filament X-ray tube and a tungsten plate are used as the X-ray tube and the secondary target, for example, to obtain the incident X-rays 11. A tungsten filament X-ray tube and a molybdenum plate are used to obtain I2. If such an X-ray tube and secondary target are used, the measurement angle on the low angle side (φ1 (≦φ2)ψ, (≦φ2
)) can be set to 15° or more, and the condition (b) above can be fully satisfied. As a result, the influence of fluctuations in the measurement distance and measurement angle due to the fluttering of the surface of the plated steel plate 11 can be reduced.

Note that the accuracy improves as there is a difference between Xl and I2 in the characteristics with respect to the amount of plating and Fe%, so I2 is set to 1.
The incident X-rays have a smaller attenuation to the plating film compared to 1, and the measurement angle (φ2.φ2) is also larger than (φ1.ψ1〉), and the maximum depth at which fluorescent Furthermore, in order to reduce measurement distance fluctuations, the beam diameter of the incident X-rays must be made small, and
The field of view of the detector is enlarged, and the incident x
It is desirable to detect vA. Therefore, the incident side is φ2
A pinhole collimator of ~5■ can be realized by opening the window of the detector on the light receiving side.

Next, as another method of the invention, when it is possible to use a large number of standard samples, the standard samples are used instead of the theoretical calculation formula to determine the amount of plating, the composition of the plating film, and the fluorescent X-rays. The amount of plating deposited and the composition of the plating film on the plated steel sheet 11 to be measured may be determined using a relational expression of the strength or the strength ratio, that is, a calibration curve.

Next, an embodiment of the device of the present invention will be described using FIG. 3. In the figure, 11 is a plated steel plate to be measured,
A measurement system 12 is installed above the plated steel plate 11. This measurement system 12 includes two systems that generate X-rays in a predetermined direction.
X-ray tubes 21.31 and pinhole collimators 22.32 that function as slits from the X-ray tubes 21.31.
A reflective secondary target 23.33 generates characteristic X-rays from white X-rays incident through the target and makes the generated characteristic X-rays incident on the plated steel plate 11 to be measured at a desired angle of incidence It. , a detector 25, and a detector 25, which measures the fluorescence X-ray intensity obtained from the plated steel plate 11 to be measured through a flat plate slit 24, 34 whose width is variable.

26.36 is a pinhole collimator. In addition, these X-ray tubes 21.31, reflective secondary targets 23.33
, slit 22.24.32,34, detector 25°35
etc. can be adjusted in position using a drive control signal from the drive control section 13.

14 is a signal processing means, which includes two detectors 25
．． Theoretical value conversion means 1 for converting the fluorescent X-ray intensity or intensity ratio measured in 35 into a theoretical intensity or intensity ratio, that is, a theoretical value.
5. Theoretical value calculation means 16 that calculates a theoretical value using an existing fluorescent X-ray intensity calculation formula using the plating adhesion amount and Fc% as variable parameters, and the theoretical value calculated by the theoretical value conversion means 15 and the theoretical value calculation means 16. The parameter value determining means 17 determines a parameter that is equal to the obtained theoretical value, and by using this parameter value as the plating amount and plating film composition, the plating amount and plating film composition of the plated kohan to be measured are determined. The composition is obtained.

Next, the operation of the apparatus configured as above will be explained.

White X-rays generated from the two X-ray tubes 21.31 pass through a pinhole collimator 22.32 and further strike a reflective secondary target 23.33 to generate characteristic X-rays.

The characteristic X-rays generated from the secondary targets 23 and 33 have an incident angle of φ3.
It is irradiated at an angle of φ2. Note that the reflective secondary target 23 is irradiated with white X-rays generated from the X-ray tube 21,
From now on, the incident x will have a large attenuation against the plating film! II
+ is taken out and used as the incident X-ray to the plated steel plate 11 to be measured, and on the other hand, the white X-ray generated on the X-ray tube 31 side is taken out from the reflective type 2
Next, the target 33 is irradiated, and incident X-rays I2, which are much less attenuated with respect to the plating film than the incident X-rays 11, are taken out and used as incident X-rays on the plated steel plate 11 to be measured.

After irradiating the incident X-rays I, , 12, the α-ray intensity of Zn and Fe generated from the plated steel plate 11 to be measured is measured at the acceptance angle ψ1. It is detected by the detector 25.35 at an angle of ψ2. Thereafter, it is obtained by the rain detector 25.35 using the theoretical value conversion means 15.

After determining the XI and X2 based on the fluorescent X-ray intensity etc. obtained, the values are converted to theoretical values and the parameter value determining means 17
Send to. On the other hand, the theoretical value calculation means 16 sequentially uses the plating deposition amount and Fe% as variable parameters and sends the theoretical values to the parameter value determination means 17 while calculating them using the existing fluorescent X-ray intensity calculation formula. Therefore, this parameter value determining means 17 executes a predetermined calculation using the theoretical value sent from the theoretical value converting means 15 and the theoretical value obtained by sequentially changing the parameters in the theoretical value calculating means 16, and Parameter values at which the theoretical values become equal are determined, and from these parameter values, the amount of plating deposited and the composition of the plating film on the steel plate 11 to be measured are obtained.

Incidentally, FIGS. 4 and 5 are diagrams showing analysis results obtained using the apparatus shown in FIG. 3. Of these, FIG. 4 shows the amount of plating deposited, and FIG. 5 shows the composition of the plating film. As is clear from these figures, even though this is an actual line that includes measurement distance fluctuations, measurement angle fluctuations, temperature and humidity fluctuations, etc., highly accurate measurements can be made in a short measurement time of 10 seconds. In addition, this analysis value was obtained from the intensity ratio of Fe and Zn fluorescent X-rays rather than the fluorescent X-ray intensity of Fe or Zn, but by taking this intensity ratio, it is possible to reduce the effects of temperature/humidity fluctuations and changes over time. .

Note that the apparatus of the present invention was performed using a theoretical calculation formula, or may be performed using a calibration curve in place of this theoretical calculation formula.

Further, in FIG. 3, a two-tube system is used, but since a normal X-ray tube has a plurality of X-ray extraction windows, it is also possible to use a one-tube system.

In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

〔Effect of the invention〕

As explained above, according to the present invention, various effects can be achieved as described below.

First, in the inventions of claims 1 and 2, by using a secondary target, X-rays with wavelengths that are largely absorbed by the plating film are extracted and irradiated onto the plated steel plate to be measured, so that fluorescence can be detected at a larger measurement angle than in the past. It is possible to measure X-ray intensity, reduce the influence of measurement distance fluctuations and measurement angle fluctuations due to fluttering of the plated steel plate to be measured, and enter t4. IX
The influence of line spectrum fluctuations can be reduced. Further, since characteristic X-rays generated from the secondary target are used as incident X-rays, wavelength integration is not required, and measurement accuracy can be improved and measurement time can be shortened.

Further, several types of standard samples are required for measurement in order to obtain conversion parameters from actual measured values to theoretical values, and the standard sample can be suitable for online measurement.

Next, the inventions of claims 3 to 6 can be realized with a very simple configuration, and the coating amount and coating composition of the plated steel sheet to be measured can be measured with high precision online, which improves the quality of plated products. It can make a big contribution.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between X-rays and a plated steel plate to be measured when using the method of the present invention, Fig. 2 is a diagram illustrating the analysis operation by the method of the present invention, and Fig. 3 is a diagram of the apparatus of the present invention. A configuration diagram showing one embodiment, and FIGS. 4 and 5 are diagrams of analysis results obtained using the apparatus of the present invention. 11... Plated steel plate to be measured, 12... Measurement system, 21
゜31...X-ray tube (X-ray generator), 23.33...
・Secondary target, 25.35...detector, 13...
- Drive control section, 14... Signal processing means, 15... Theoretical value conversion means, 16... Theoretical value calculation means, 17...
Parameter value determination means.

Claims (6)

[Claims] (1) A method for measuring the coating amount and coating composition of a plated steel sheet to be measured, which comprises the following steps (a) to (d). (a) When two types of secondary targets are irradiated with X-rays generated from an X-ray generator, and the characteristic X-rays generated from each secondary target are irradiated onto the plated steel plate at a predetermined angle of incidence, K of the target element for analysis obtained from
a step of predetermining a theoretical calculation formula for the intensity or intensity ratio of a series of fluorescent X-rays at a predetermined acceptance angle; (b) determining the theoretical calculation formula using a standard sample with a known plating amount and plating film composition; Under the same conditions as
a step of actually measuring the fluorescent X-ray intensity or intensity ratio and calculating in advance a conversion coefficient for converting this measured value into a theoretically calculated value using the theoretical calculation formula; (c) under the same conditions as those used to calculate the theoretical calculation formula; a step of measuring the fluorescent X-ray intensity or intensity ratio obtained from a plated steel sheet to be measured whose coating amount and coating film composition are unknown, and converting it into a theoretical intensity or intensity ratio using the conversion coefficient; (d) theory The theoretical strength or strength ratio obtained from the calculation formula,
A step of setting the coating amount and coating composition, which are parameters in the theoretical calculation formula, that are closest to the converted theoretical strength or strength ratio, as the coating coating amount and coating coating composition of the plated steel sheet to be measured. (2) A method for measuring the coating amount and coating composition of a plated steel sheet to be measured, which comprises the following steps (a) and (b). (a) Two types of two targets are irradiated with X-rays generated from an X-ray generator, and the characteristic X-rays generated from each secondary target are applied at a predetermined angle of incidence, and the amount of plating deposited and the composition of the plating film are known. K-series fluorescence X of the target element for analysis obtained from the standard sample when irradiated with
(b) determining the amount of plating and the amount of plating and the composition of the plating film under the same conditions as those used to determine the calibration curve; (c) measuring the fluorescent X-ray intensity or intensity ratio obtained from a plated steel sheet to be measured whose plating film composition is unknown; (c) measuring the fluorescent X-ray intensity or intensity ratio obtained from a calibration curve;
A step of setting the plating coating amount and plating film composition, which are parameters in the calibration curve, which are closest to the measured fluorescent X-ray intensity or intensity ratio, as the plating coating amount and plating film composition of the plated steel sheet to be measured. (3) An X-ray generator that generates X-rays, and a reflection-type secondary system that uses the characteristic X-rays generated by irradiating the X-rays generated by this X-ray generator as the incident X-rays on the plated steel plate to be measured. A target part, a slit system that determines the path line of the X-rays, projects them onto the plated steel plate to be measured at a predetermined angle of incidence, and receives the light at a predetermined acceptance angle, and the K-series fluorescence of the target element for analysis generated from the plated steel plate to be measured. Two detectors that measure the X-ray intensity at predetermined angles, a means for storing the theoretical intensity or the theoretical calculation formula for the intensity ratio that should be obtained by these measurement systems, and the actually measured fluorescent X-ray intensity. or a means for converting the strength ratio into a theoretical strength or strength ratio, and a plating coating amount and a plating film composition that minimize the difference between the converted theoretical strength or strength ratio and the theoretical strength or strength ratio obtained by a theoretical calculation formula. A measuring device for measuring the amount of plating deposited on a plated steel sheet and the composition of the plating film, comprising a means for determining the coating amount and the composition of the plating film on a plated steel sheet. (4) An X-ray generator that generates X-rays, and a transmission-type secondary system that uses the characteristic X-rays generated by irradiating the X-rays generated from this X-ray generator as the incident X-rays on the plated steel plate to be measured. A target section, a slit system that determines the X-ray pass line and projects it onto the plated steel plate to be measured at a predetermined incident angle and receives the light at a predetermined acceptance angle, and K-series fluorescent X-rays of the target element to be analyzed generated from the plated steel plate. Two detectors each measuring the intensity at a predetermined angle, means for storing the theoretical intensity or the theoretical calculation formula for the intensity ratio that should be obtained with these measurement systems, and the actually measured fluorescent X-ray intensity or intensity. Plating coverage and plating film of a plated steel sheet, comprising means for converting the ratio into theoretical strength or strength ratio, and means for determining plating adhesion and plating film composition that minimize the difference between the converted theoretical strength or strength ratio. Composition measuring device. (5) An X-ray generator that generates X-rays, and a reflection-type secondary system that uses the characteristic X-rays generated by irradiating the X-rays generated from this X-ray generator as the incident X-rays on the plated steel plate to be measured. A target section, a slit system that determines the para-line of the X-rays and projects them onto the plated steel plate to be measured at a predetermined angle of incidence and receives the light at a predetermined acceptance angle, and a K-series fluorescent X-ray of the element to be analyzed generated from the plated steel plate to be measured. Two detectors each measuring the line intensity at a predetermined angle, means for storing a calibration curve of the theoretical intensity or intensity ratio to be obtained with these measurement systems, and fluorescent X-ray intensity or intensity actually measured. A measuring device for measuring the coating amount and coating composition of a plated steel sheet, comprising means for determining the coating coating amount and coating coating composition that minimize the difference between the fluorescent X-ray intensity or the intensity ratio obtained from the ratio and the calibration curve. (6) An X-ray generator that generates X-rays, and a transmission type secondary system that uses the characteristic X-rays generated by irradiating the X-rays generated from this X-ray generator as the incident X-rays on the plated steel plate to be measured. A target part, a slit system that determines the path line of the X-rays, projects them onto the plated steel plate to be measured at a predetermined angle of incidence, and receives the light at a predetermined acceptance angle, and the K-series fluorescence of the target element for analysis generated from the plated steel plate to be measured. Two detectors each measure X-ray intensity at a predetermined angle, a means for storing a calibration curve of the theoretical intensity or intensity ratio to be obtained with these measurement systems, and a means for storing a calibration curve of the theoretical intensity or intensity ratio to be obtained with these measurement systems, and a means for storing the fluorescent A measuring device for measuring the coating amount and coating composition of a plated steel sheet, comprising means for determining the coating coating amount and coating coating composition that minimize the difference between the intensity ratio and the fluorescent X-ray intensity or intensity ratio obtained from a calibration curve.