JP2919295B2 - Method of measuring the amount of annealed separator applied to grain-oriented electrical steel sheets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of grain-oriented electrical steel sheets mainly used for transformer cores, and more particularly to a method for measuring the amount of an annealing separator applied after decarburizing annealing.

[0002]

2. Description of the Related Art When producing grain-oriented electrical steel sheets, an annealing separator containing MgO as a main component is applied after decarburizing annealing. The purpose is roughly divided into the following two.

The first purpose is to prevent image sticking. That is, the grain-oriented electrical steel sheet after the decarburizing annealing is finish-annealed at a high temperature of about 1200 ° C. At this time, if the steel sheets are in direct contact with each other, they are seized, and this is prevented.

[0004] The second purpose is to form an insulating film. The grain-oriented electrical steel sheets are used in layers, but the steel sheets need to be insulated from each other. This insulating film is formed by an oxide layer formed by decarburizing annealing and Mg applied after decarburizing annealing.
This is performed by the reaction of O.

[0005] This insulating film has an effect of improving magnetic properties by applying tension to the steel sheet in addition to the above-mentioned insulating effect. In order to stably apply the tension, it is necessary that the insulating film be dense with good adhesion to the steel sheet.

[0006] Therefore, in order to obtain such a good quality insulating film, the mass of the oxide layer formed by decarburization annealing is made appropriate, and the various properties and coating amount of MgO are strictly controlled. Need to be managed.

The amount of metal plating on the surface of the steel sheet or the metal,
For measuring the amount of nonmetal applied, a measuring method using radiation is generally known (JP-A-53-42762).
This is because, as shown in FIG. 4, the radiation emitted from the radiation source 1 hits the steel sheet metal surface (Fe), and as a result, characteristic X-rays of Fe emitted from the surface are detected. Since the intensity of the characteristic X-ray is attenuated by the attached matter, the basic principle is to measure the thickness of the attached amount from the amount of attenuation.

Radiation emitted from the radiation source 1 at a constant intensity emits characteristic X-rays of Fe from the surface of the steel sheet metal.
This characteristic X-ray amount is detected by the detector 2 and converted into an electric signal by the converter 3. When the positional relationship between the steel plate and the detector 2 is constant, if there is a uniform deposit on the surface, the characteristic X-ray dose is attenuated by the characteristics of the substance, so that the electric signal and the amount of deposit on the surface are as shown in FIG. Functional relationship. That is, the amount of adhesion on the surface can be detected by detecting the electric signal.

[0009]

However, in the above detection method, when the positional relationship between the steel plate and the detector changes, this functional relationship also changes. In particular, the detection amount greatly changes with respect to the steel plate inclination in the rotation direction about a straight line perpendicular to the plan view of FIG. This change in the characteristic X-ray detection amount is mainly caused by a change in the thickness of the deposit of the characteristic X-ray radiated from the surface of the steel sheet before reaching the detector 2. It is expressed as Expression 1 by the steel plate inclination Δθ.

[0010]

(Equation 1) Here, I ₀ : the characteristic X-ray detection amount when the steel plate inclination is 0 I: the characteristic X-ray detection amount when the steel plate inclination is Δθ μ ₁ : the absorption coefficient of the attached substance of the radiation source (constant term) μ ₂ : the characteristic of the detection target Absorption coefficient of X-ray adhering substances (constant term) α: Angle between the line connecting the detector and the detection point on the steel sheet with respect to the vertical line on the steel sheet surface

[0011] The change in the characteristic X-ray detection amount may be, for example, up to about 20% of the characteristic X-ray attenuation by the annealing separator when there is a change of Δθ = 3 ° when measuring the steel sheet to which the annealing separator is attached. And accurate detection cannot be expected.

In order to eliminate such an error due to the inclination of the steel sheet, for a steel sheet to which an annealing separating agent has adhered, a method of using a contact roll or applying a tension to the steel sheet of the measuring unit is considered. This method cannot be adopted because the annealing separating agent peels off.

[0013] A method is also known in which the amount of adhesion is determined from the measured amount of coating at two points (plural points) on the steel sheet and the inclination of the steel sheet between the two points, but the inclination of the steel sheet is not always uniform. , Resulting in an error.

Therefore, at present, the amount of coating per unit area of a steel sheet is measured by a gravimetric method using cut samples, and accurate on-line measurement cannot be performed.

The problem to be solved by the present invention is to provide a method capable of measuring the amount of annealed separating agent with high accuracy even when the steel sheet is slightly inclined.

[0016]

In order to solve the above-mentioned problems, a method for measuring the amount of an annealing separator applied to a grain-oriented electrical steel sheet according to the present invention is as follows. Irradiates the surface of the steel sheet with radiation from a radiation source,
When detecting characteristic X-rays generated from a steel sheet by detecting them with a detector, the two detectors are arranged at symmetrical positions with respect to the radiation source, and the intensity of the X-rays detected by the two detectors is determined.
The application amount of the annealing separating agent is determined based on the arithmetic mean value of the degrees .

[0017]

The relationship between the inclination of the steel sheet Δθ and the error from the true value of the measured value of the amount of adhesion of the steel sheet surface obtained by the calibration curve when Δθ = 0 is almost symmetrical and linear in the range of small inclination of the steel sheet. Become a target. Therefore, by arranging the two detectors at positions symmetrical with respect to the radiation irradiation surface and averaging the detection results of the adhesion amounts of the two detectors, it is possible to eliminate an error due to the steel plate inclination Δθ. As a result, even for an object such as an annealing separator in which the pass line cannot be stabilized by the contact roll, it is possible to detect the attached amount accurately online.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments. FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention. In the figure, 1 is a radiation source, 2A and 2B are X
Line detectors, 3A and 3B are signal converters for converting the detected amount into electric signals, 4A and 4B are adhesion amount converters containing a calibration curve for converting the X-ray detection amount to the adhesion amount on the steel sheet surface, and 5 is the adhesion amount converter. An arithmetic unit 6 for averaging the information of the adhesion amounts converted by the amount converters 4A and 4B, and 6 denotes a display / recording device.

FIG. 3 shows the relationship between the steel sheet inclination Δθ and the error from the true value of the measured value of the steel sheet surface adhesion amount obtained from the calibration curve when Δθ = 0. In a small range of the steel plate inclination, for example, in the range of | Δθ | ≦ 3 °, the origin is almost symmetric. That is, as shown in FIG. 1, the detectors 2A and 2B are arranged at positions that are line-symmetric with respect to the radiation irradiation surface. According to equation (1), the detection outputs of the detectors 2A and 2B are as follows.

When the detector is configured as a normal detector, equation (1)
In the above, a wavelength satisfying μ ₁ << μ ₂ is selected. Therefore, the first term of equation (1) may be ignored. That is, the amount detected by one of the detectors is expressed by equation (2).

(Equation 2) Here, I _{1 is} the characteristic X-ray detection amount when the steel plate inclination is Δθ.

When a detector is installed on the opposite side across the radiation source as shown in FIG. 1, the amount of detection by the detector has a slope Δθ
Acts in the opposite direction, and is therefore expressed by equation (3).

(Equation 3) Here, I _{2 is} the characteristic X-ray detection amount when the steel plate inclination is Δθ.

Taking the average of I ₁ and I ₂ , equation (4) holds under the condition of Δθ << α.

(Equation 4)

Equation (4) is not affected by Δθ. That is, the detected amount is constant even if Δθ fluctuates.

As described above, by taking the average of the detection results of the adhesion amounts of the two, an error due to the steel plate inclination Δθ can be eliminated. As a result, even for an object such as an annealing separator in which the pass line cannot be stabilized by the contact roll, it is possible to detect the attached amount accurately online.

[0025]

As described above, according to the present invention, two detectors are arranged symmetrically with respect to the X-ray source, and characteristic X-rays from the surface of the steel sheet are detected and averaged. As a result, the error caused by the inclination of the steel sheet is offset, and a high-precision amount of the applied annealed separating agent is obtained. Therefore, high-precision measurement, which was conventionally difficult online, can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a characteristic X-ray detection amount and a surface adhesion amount.

FIG. 3 is a graph showing the relationship between the inclination of a steel sheet and an error in detection of the amount of adhesion.

FIG. 4 is an explanatory diagram of the principle of a method for detecting the amount of attached matter using X-rays.

FIG. 5 is a graph showing a tilt angle of a steel sheet and a variation characteristic of a detected X-ray dose.

[Explanation of symbols]

1 radiation source, 2A, 2B X-ray detector, 3A, 3B
Signal converter, 4A, 4B adhesion amount converter, 5 arithmetic unit, 6
Display and recording device

──────────────────────────────────────────────────続 き Continuing from the front page (72) Osamu Sekiguchi 1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi Nippon Steel Corporation Yawata Works (72) Inventor Naoki Matsuura 14-8 Akaoji-cho, Takatsuki-shi, Osaka No. Rika Denki Kogyo Co., Ltd. (56) References JP-A-1-242908 (JP, A) JP-A-59-222586 (JP, A) JP-A-2-250980 (JP, A) JP-A-60 -133308 (JP, A) JP-A-64-59044 (JP, A) JP-A-53-42762 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 23/22- 23/227 C23C 22/00 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. The amount of an annealing separator applied to a decarburized annealed grain-oriented electrical steel sheet is determined by irradiating radiation from a radiation source onto the steel sheet surface and detecting characteristic X-rays generated from the steel sheet by a detector. In the calculation, two detectors were arranged at symmetrical positions with respect to the radiation source, and detected by the two detectors.
A method for measuring the amount of an annealing separator applied to a grain-oriented electrical steel sheet, wherein the amount of an annealing separator applied is determined based on an arithmetic mean value of X-ray intensities .