JPH0768318A - Method for foreseeing occurrence of scratch defect on surface of steel sheet - Google Patents

Abstract

PURPOSE:To foresee the occurrence of scratch defect on the surface of a steel sheet that is generated in a coiler. CONSTITUTION:The position in the width direction in the end part of the steel sheet 1 which is inserted into the coiler 2 for steel sheet in a rolling line is detected 3, a specific frequency compoment is extracted and the sheet shifting amount in the thickness direction in both end parts and its phase are detected. Or, the sheet shifting amount (moving amount) in the diameter increasing direction of coil in the end part of coil is detected, specific frequency compoment is extracted from it. The occurrence of scratch on the surface of the steel is foreseen based on the signal level of the frequency component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of predicting a flaw or flaw on a surface of a steel sheet in a steel sheet winding device.

[0002]

2. Description of the Related Art In a winding apparatus for a steel plate, a scratch defect that occurs on the surface of the steel plate when the steel plate is wound is a scratch that is caused by the overlapping of the steel plate and the steel plate when the steel plate is wound into a coil. As a conventional technique for preventing the occurrence of the scratches, there are those disclosed in, for example, JP-A-60-37222 and JP-A-4-415. In Japanese Patent Application Laid-Open No. 60-37222, a lubricant is applied to the surface of a steel sheet to prevent the occurrence of surface flaws between the steel sheets, but it could not be applied to a non-oil coated steel sheet. Further, in Japanese Utility Model Laid-Open No. 4-415, a vibration sensor is installed in a bearing portion of a reel shaft of a coil winding device, and vibration and displacement in the bearing portion are detected to prevent occurrence of steel plate surface scratches. However, since it detects the vibration of the bearing part of the reel shaft of the coil winding device, it does not detect the actual behavior and vibration of the steel plate, so the detection of scratches at the initial stage is delayed, and it is also detected. The precision was also low.

[0003]

In the conventional steel sheet winding device, as described above, there is no epoch-making technique for predicting scratches quickly and accurately, and when scratches are generated, scratch defects are detected. The coil with which it is sent is sent to the next process and is degraded, which causes a decrease in yield, and scratch defects are a major problem in quality control. In order to solve such problems, it is desirable to determine the presence or absence of occurrence of scratches at the early stage of coil winding and deal with it, and for that purpose it is necessary to elucidate the mechanism of occurrence of scratch defects. However, the situation has not been clarified yet.

The present invention has been made to solve the above-mentioned problems, and it is possible to predict the occurrence of scratch defects on the surface of a steel sheet that occurs in the winding device. It is an object of the present invention to provide a method for predicting the occurrence of scratch defects.

[0005]

A method for predicting a scratch defect on a surface of a steel sheet according to the present invention (claim 1) is directed to a position in the width direction of an end portion of the steel sheet inserted into a winding device for the steel sheet in a rolling line. Is detected, a frequency component that coincides with the rotation frequency of the winding device is extracted from the position detection signal, and the occurrence of scratches on the surface of the steel sheet is predicted based on the signal level of the frequency component. A method for predicting a scratch defect on a steel plate surface according to the present invention (claim 2) detects a plate runout amount and a plate runout phase in the plate thickness direction at both ends of a steel plate to be inserted into a steel plate winding device on a rolling line. , Predict a flaw defect on the surface of the steel plate based on the detected plate shake amount and the phase of the plate shake.
A method for predicting the occurrence of a scratch defect on the surface of a steel sheet according to the present invention (claim 3) is a deflection amount in a coil winding thick direction of an end portion of a coil (steel sheet) wound in a coil by a steel sheet winding device on a rolling line. Detects the amount of movement, extracts the frequency that matches the rotation frequency of the winding device from the detected amount of coil deflection or movement, and predicts the occurrence of scratches on the steel plate surface based on the signal level of that frequency component. To do.

[0006]

According to the method of predicting a scratch defect on the surface of a steel sheet according to the present invention (claim 1), the position in the width direction of the end portion of the steel sheet inserted into the winding device for the steel sheet is detected and the position detection signal is detected. The frequency component is analyzed to extract a predetermined frequency component, and based on the signal level of the frequency component, the steel plate and the steel plate overlap with each other while fluttering, and the state of the scratches with scratches is detected in advance to detect the scratch defect. It prevents the occurrence. The occurrence of a scratch defect occurs in the process of winding the steel plate into a coil in the coiling device for the steel plate. At the initial stage of winding (no occurrence of a scratch defect), the position detection signal at the end of the steel plate is detected. The signal level of the frequency component that matches the rotation frequency of the take-up device is low, the meandering and fluttering of the edge of the steel plate always show the same amount, and the operation amount is also small so that no scratches occur, and the steel plate There is also no flaw.

When the steel plate is wound into a coil and the coil is thickened at a certain point, the signal level of the frequency component of the position detection signal, which coincides with the rotation frequency of the winding device, gradually increases, and The amount of meandering and flapping gradually increases. When the amount of meandering and flapping at the edge of the steel sheet increases and scratches start to occur on the surface of the steel sheet, the signal level of the frequency component at this time also rises. Therefore, the occurrence of scratch defects on the surface of the steel sheet can be predicted based on this signal level.

The form and timing of the scratches generated on the steel plate differ depending on the plate thickness, plate width, and steel type.
Scratches tend to occur easily in materials with thick plate thickness and narrow plate width (occurrence occurs from a coil diameter that is small to some extent), and in materials with thin plate thickness and wide plate width, scratches are likely to occur. Although it occurs, the time of occurrence is late and the degree of scratches tends to be relatively light. Further, the form and timing of occurrence of scratches differ depending on the steel type of the plate, and the harder the material, the more likely it is to occur. As described above, since the occurrence state and timing of scratches differ depending on the thickness, width and steel type of the steel sheet, the threshold value indicating the timing of occurrence of scratches differs every time. here,
The method of determining the threshold value that indicates the occurrence of scratches depends on the winding device of the line.Be sure to fully understand the relationship between the form and timing of scratches and the thickness, width, and grade of the steel sheet. A threshold must be determined.

In the method for predicting steel plate surface flaw defects according to the present invention (Claim 2), the plate runout amount in the plate thickness direction of both ends of the steel plate inserted into the steel plate winding device is detected, and the plate runout amount is detected. And, based on the phase, the steel plate and the steel plate overlap with each other while fluttering, and the state of the scratches with scratches is detected in advance,
Prevents the occurrence of scratches. As described above, the occurrence of scratches occurs in the process of winding the steel plate into a coil in the winder for winding the steel plate, but at the initial stage of winding (without the occurrence of scratches), the runout of both ends of the steel plate The amount shows the same plate runout amount, and since both ends of the steel plate move in the same phase, scratches do not occur. Further, since the plate runout amount in the plate thickness direction at both ends of the steel plate is small, the steel plate is not scratched. When the steel sheet is wound into a coil and the coil becomes thicker, the amount of runout at the edge of the steel sheet gradually increases at some point, and the movement of the edge of the steel sheet changes from the in-phase state to the phase form. The phase gradually changes, and scratches start to occur at the time when the movements of the edges of the steel sheet in the thickness direction are completely opposite in phase. In this way, the occurrence of scratch defects on the surface of the steel plate is predicted by detecting when the amount of plate deflection in the thickness direction of the edge of the steel plate exceeds a certain threshold value and by detecting the state where the plate deflection is in the opposite phase. be able to.

In the method for predicting a scratch defect on the surface of a steel sheet according to the present invention (claim 3), the runout amount or the movement amount of the end portion of the coil (steel sheet) wound in a coil shape is detected by a steel sheet winding device. , A frequency that matches the rotation frequency of the winding device is extracted from the detected coil runout amount or movement amount, and based on the signal level of the frequency component, the steel plate and the steel plate overlap with each other while flapping and scratches The state of is detected in advance to prevent the occurrence of scratches. The occurrence of scratches occurs in the process of winding the steel plate into a coil in the winding device for the steel plate. At the beginning of winding (no occurrence of scratch defects), the runout amount of the coil end is The signal level of the frequency component that coincides with the rotation frequency of the device is low, the wobbling movement of the coil always shows the same amount, and since the amount of movement thereof is also small, no scratches occur and the steel plate is not scratched. At a certain point when the steel plate is wound into a coil and the coil is wound and thickened, as in the case described above,
The signal level of the frequency component that corresponds to the rotation frequency of the winding device of the amount of shake of the coil end gradually increases, and the amount of wobbling movement of the coil gradually increases. When the wobbling movement of the coil end portion becomes large and scratches start to occur on the surface of the steel sheet, the signal level of the frequency component at this time also becomes high. Therefore, the occurrence of scratch defects on the surface of the steel sheet can be predicted based on this signal level. Here again, the occurrence of flaws on the steel sheet varies depending on the thickness, width, and type of steel. Scratches tend to occur in materials with a large thickness and a narrow width (occurrence occurs from a coil diameter that is small to some extent), and in materials with a small thickness and a wide width, scratches Occurrence occurs, but the time of occurrence is slow and the degree of scratches tends to be relatively light. Further, the form and timing of occurrence of scratches differ depending on the steel type of the plate, and the harder the material, the more likely it is to occur. As described above, the form and timing of occurrence of scratches differ depending on the plate thickness, width and steel type of the steel sheet, so that the threshold value indicating the timing of occurrence of scratches differs every time. Here, the method of determining the threshold value that indicates the occurrence of scratches differs depending on the winding device of the line.Be sure to fully understand the relationship between the occurrence mode and timing of scratches and the thickness, width and grade of steel sheet. The threshold must be determined after that.

[0011]

【Example】

Example 1. FIG. 1 is a diagram showing the configuration of an apparatus for carrying out the method for predicting a scratch defect on the surface of a steel sheet according to an embodiment of the present invention.
The steel plate 1 is wound by the steel plate winding device 2 as shown in the figure, and the position of the end of the steel plate 1 in the plate width direction is detected by the position detector 3. The position detector 3 is arranged immediately before the final defrost 4 on the exit side, and detects the position in the plate width direction of the end of the steel plate 1 immediately before the final deflour 4. The position detection signal from the position detector 3 is sent to the calculator 5, and the calculator 5 frequency-analyzes the position detection signal, extracts a frequency component that matches the rotation frequency of the reel of the winding device, and determines its signal level. Ask.

2 to 4 show a plate thickness of 0.2 mm and a plate width of 850.
It is a timing chart showing the position detection signal of the position detector 3 when the steel plate of mm is wound on the winding device, the position detection amount of the position detector 3 is plotted on the vertical axis, and the time is plotted on the horizontal axis. Shows. Figure 2 shows a coil diameter of about 2200
It shows the state of the position detection signal of the position detector 3 when the steel plate is scratched when the distance is mm, and the position detection signal is about 0.4V in voltage (reel rotation frequency 0.8H
z). FIG. 3 shows the state of the position detection signal of the position detector 3 when there is no scratch on the steel plate when the coil diameter is about 1400 mm, and the position detection signal of the position detector 3 is a voltage of about 0. 08V (reel rotation frequency 1.25
Hz). In Figure 4, the coil diameter is about 19
The state of the position detection signal of the position detector 3 that appears immediately before the occurrence of scratches when the distance is 00 mm is shown. The position detection signal is about 0.15 V in voltage (rotation frequency 0.95 Hz).
Is. When the calculator 5 detects that the position detection signal of the position detector 3 changes to the level of the state of FIG. 4 (position detection signal: about 0.15 V), the occurrence of scratch defects on the surface of the steel plate Can be predicted. When the occurrence of a scratch defect on the surface of the steel sheet is predicted, an alarm is issued to call attention.

Example 2. FIG. 5 is a view showing an apparatus for carrying out a method for predicting a scratch defect on the surface of a steel sheet according to another embodiment of the present invention. The amount of plate shake in the plate thickness direction at both ends of the steel plate 1 immediately before being wound up by the steel plate winding device 2 is detected using displacement meters 6 and 7 such as a laser, and the amount of plate shake is output to the calculator 5. Then, the calculator 5 calculates the phase of the plate runout at both ends. Also in this embodiment, the displacement gauges 6 and 7 are arranged immediately after the final defrost 4 on the exit side to detect the plate runout amount at both ends immediately after the final deflor 4.

6 to 8 show a plate thickness of 0.2 mm and a plate width of 850.
It is a timing chart showing the plate runout amount of the steel plate edge when a steel plate of mm is wound around the winding device, the vertical axis shows the plate runout amount, and the horizontal axis shows the time. In these figures, the plate displacement (Op) is the measurement result by the displacement gauge 7, and the plate displacement (Dr) is the measurement result by the displacement gauge 6. Fig. 6 shows the steel plate 1 when the coil diameter is about 2200 mm.
The figure shows the state of plate runout when scratches are generated. The plate runout amount is about 2.0 mm, and the phase of the plate runout is completely opposite. FIG. 7 shows a coil diameter of about 1400.
It shows the state of plate runout when there is no occurrence of scratches on the steel plate 1 in mm, the plate runout amount is about 0.7 mm, and the plate runout runs in the same phase. Figure 8 shows a coil diameter of about 190
The plate run-out state that appears immediately before the occurrence of scratches at 0 mm is shown, and a state in which the phase of the steel plate 1 is changing from the same phase to the opposite phase is observed, and the plate run-out amount is about 1 mm. When the calculator 5 detects the change of the steel sheet from the state of FIG. 7 to the state of FIG. 8 (phase change / plate deflection amount of 1 mm), it is possible to predict the occurrence of scratch defects on the steel plate surface. In addition, in FIG. 8, (b) is an enlarged display of the time axis of (a).

Example 3. FIG. 9 is a diagram showing the configuration of an apparatus for carrying out the method for predicting a scratch defect on the surface of a steel sheet according to one embodiment of the present invention. The steel plate 1 is wound by the steel plate winding device 2 as shown in the drawing to form a coil, and the amount of movement (movement amount) of the end of the coil (steel plate) is detected by the eddy current type distance detector 3a. This detector is arranged in the vicinity of the reel shaft of the steel plate winding device, and detects the shake amount (movement amount) of the end of the coil (steel plate) being wound. The distance signal from the shake amount (movement amount) of the end of the coil (steel plate) is sent to the calculator 5, and the calculator 5 performs frequency analysis on the distance signal, and based on the detected shake amount (movement amount) of the coil. A frequency component corresponding to the rotation frequency of the winding device is extracted and its signal level is obtained. In this embodiment, in order to detect the deflection of the coil in the coil thickening direction while keeping the measurement distance constant, the eddy current type distance detector 3a is moved in the direction of arrow A at a constant speed corresponding to the coil winding thickening speed. Move with.

10 to 12 show a plate thickness of 0.2 mm and a plate width of 8
It is a timing chart showing a distance signal which detects the deflection amount of the end portion of the coil (steel plate) when winding a 50 mm steel sheet around the winding device, and the deflection amount of the coil end portion on the vertical axis,
The horizontal axis shows time. In Fig. 10, the coil diameter is about 22.
It shows the amount of deflection at the end of the coil when the steel plate is scratched at 00 mm, and the amount of deflection is about 2.1 m.
m (reel rotation frequency 0.8 Hz). FIG. 11 shows the deflection amount of the coil end when the coil diameter is about 1400 mm and no scratches are generated on the steel plate, and the deflection amount is about 0.7 mm (reel rotation frequency 1.25 Hz). Fig. 12 shows the amount of deflection of the coil end that appears immediately before the occurrence of scratches when the coil diameter is about 1900 mm, and the amount of deflection is about 1.0 mm (reel rotation frequency 0.9
5 Hz). By detecting that the distance signal of the deflection amount of the coil end portion changes to the level in the state of FIG. 12, the arithmetic unit can predict the occurrence of scratch defects on the steel plate surface. When the occurrence of a scratch defect on the surface of the steel sheet is predicted, an alarm is issued to call attention.

[0017]

As described above, according to the present invention, the position in the plate width direction of the end portion of the steel plate to be inserted into the steel plate winding device is detected, and a specific frequency component is extracted therefrom to extract the plate at both ends. The amount of plate runout in the thickness direction and its phase are detected, or the amount of movement (runout amount) of the coil end in the coil winding thickening direction is detected and a specific frequency component is extracted from it, causing the occurrence of scratches on the steel plate surface. Since it is possible to predict, it is possible to reliably predict scratches on the surface of the steel plate, which was a chronic defect that occurs in the steel sheet winding device, and the deterioration due to scratches is reduced, leading to improved yield. .

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an apparatus for carrying out a method for predicting a scratch defect on a surface of a steel plate according to an embodiment of the present invention.

FIG. 2 is a timing chart showing a position detection signal in the plate width direction of an end part of a steel plate inserted into the winding device when a scratch defect is generated on the steel plate surface.

FIG. 3 is a timing chart showing a position detection signal in the plate width direction of the end part of the steel plate inserted into the winding device when no scratch defect is generated on the steel plate surface.

FIG. 4 is a timing chart showing a position detection signal in the plate width direction of the end part of the steel plate inserted into the winding device immediately before the occurrence of a scratch defect on the steel plate surface.

FIG. 5 is a diagram showing a configuration of an apparatus for carrying out a method for predicting a scratch defect on the surface of a steel plate according to another embodiment of the present invention.

FIG. 6 is a timing chart showing the state of plate runout in the plate thickness direction at both ends of the steel plate inserted into the winding device when a scratch defect is generated on the surface of the steel plate.

FIG. 7 is a timing chart showing the state of plate runout in the plate thickness direction at both ends of the steel plate inserted into the winding device when no scratch defects are generated on the steel plate surface.

FIG. 8 is a timing chart showing plate runout in the plate thickness direction at both ends of a steel plate inserted into a winding device immediately before a scratch defect occurs on the steel plate surface.

FIG. 9 is a diagram showing a configuration of an apparatus for carrying out a method for predicting a scratch defect on the surface of a steel sheet according to another embodiment of the present invention.

FIG. 10 is a timing chart showing the deflection amount of the coil end portion wound around the winding device when a scratch defect is generated on the steel plate surface.

FIG. 11 is a timing chart showing the amount of deflection of the end portion of the coil wound by the winding device when no scratch defect is generated on the surface of the steel sheet.

FIG. 12 is a timing chart showing a deflection amount of a coil end portion wound around a winding device immediately before a scratch defect occurs on a surface of a steel sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel plate 2 Steel plate winding device 3 Position detector 3a Eddy current type distance detector 4 Deflector roll 6,7 Laser type displacement meter

Front Page Continuation (72) Inventor Akihiko Murakami 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Tokio Wakabayashi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Pipe Incorporated (72) Inventor Ryuto Enomoto Marunouchi 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Yasuo Orido Marunouchi 1-21-2 Marunouchi, Chiyoda-ku, Tokyo In-house (72) Inventor Yutaka Horiuchi Marunouchi 1-2-2 Nihon Steel Pipe Co., Ltd. in Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Isao Kobayashi 1-2-1 Marunouchi Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (3)

[Claims] 1. A position in the plate width direction of an end of a steel sheet inserted into a steel sheet winding device on a rolling line is detected, and a frequency component matching the rotation frequency of the winding device is extracted from the position detection signal. , A method for predicting the occurrence of a flaw on the surface of a steel sheet, which predicts the occurrence of a flaw on the surface of the steel sheet based on the signal level of the frequency component. 2. A plate runout amount in the plate thickness direction and a plate runout phase at both ends of a steel plate inserted into a steel plate winding device on a rolling line are detected, and the detected plate runout amount and the phase of the plate runout are detected. A method for predicting occurrence of scratch defects on a steel sheet surface, which comprises predicting scratch defects on the surface of a steel sheet based on the above. 3. A deflection amount or movement amount of a coil end portion wound in a coil shape in a coil winding direction by a coiling device for a steel plate in a rolling line is detected, and the detected deflection amount or movement amount of the coil is detected. A method for predicting the occurrence of flaws on a steel plate surface, which comprises predicting the occurrence of a flaw on the surface of the steel sheet by extracting a frequency that matches the rotation frequency of the winding device and based on the signal level of the frequency component.