JPH062051A - Method for detecting condition of metal strip travelled in horizontal furnace - Google Patents

Abstract

PURPOSE:To detect the meandering quantity, catenary quantity and strip shape at the same time regardless of the width size, etc., by applying laser beam to the travelled metal strip from a detecting instrument reciprocatively shifted in the width direction of a furnace and calculating from this reflected beam and the position. CONSTITUTION:In the horizontal furnace travelling the steel strip S in the furnace 1 through carrying rolls 2, slit 3 is arranged in the width direction at the upper part of the furnace 1. Above this slit, the detecting instrument 4 providing a laser beam oscillator 5 and a beam receiver 6 is arranged and reciprocatively shifted along the slit 3 in the center position between the carrying rolls in the furnace through a screw shaft 7 rotated by a driving motor 8. The laser beam irradiates the steel strip S in the furnace from this detecting instrument 4 through the slit 3 to detect the reflected beam. From this detected signal and a positional signal in the width direction of the furnace with a positional detector 9 fitted to the motor 8, the meandering quantity, catenary quantity and strip shape S are detected by calculation in an arithmetic device 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the state of a metal strip which can simultaneously detect the meandering amount, the catenary amount and the plate shape of a metal strip running in a horizontal furnace.

[0002]

2. Description of the Related Art In a horizontal heat treatment furnace in a magnetic steel sheet manufacturing process line, it is required to pass a sheet with a low tension from the viewpoint of preventing creep rupture and the like, and in order to manage a steel strip in such an appropriate low tension sheet passing state. Needs to know the meandering amount of steel strip in the furnace, the amount of catenary, plate shape, etc. Conventionally, as a method for detecting the amount of meandering and the amount of catenary of a steel strip running in a horizontal furnace, a method disclosed in JP-A-63-221208 is known.

According to this method, as shown in FIGS. 6 and 7, both edges of the steel strip S which is passed through the heat treatment furnace 11 are
Laser oscillator 1 through opening 12 provided at the top of the furnace
The laser beam is irradiated from 3 and the reflected light is captured by the TV camera 15 through the opening 14 also provided in the upper part of the furnace, and the distance to the steel strip S and the edge position obtained by image-processing this Then, the amount of catenary and the amount of meandering are calculated from, respectively.

[0004]

However, in this method, since the field of view of the detector in the width direction of the steel strip is limited, there is no problem in detecting the meandering amount of a material having the same width, but the width of the steel strip passed through the furnace. All materials of different sizes (eg 400-100
There was a problem that it could not cover up to 0 mm). Further, detection of the plate shape is indispensable in order to secure stable passage of the plate in the furnace, but conventionally, there is no example in which the situation of the plate shape in the furnace is directly detected quantitatively.

The present invention has been made in view of the above-mentioned conventional problems. The present invention has been made in view of the meandering amount, the catenary amount, and the plate shape of a metal strip running in a horizontal furnace at the same time and regardless of the width size of the metal strip. It is intended to provide a method capable of detecting.

[0006]

According to the method of the present invention for achieving such an object, a detection device provided with a laser oscillator and a photodetector is provided in the width direction of the upper part of the furnace body at the center position between the transfer rolls in the furnace. It is reciprocally moved along the slit provided, the laser oscillator of the moving detection device irradiates the inside of the furnace with laser light through the slit, and the reflected light is detected by the light receiver, and this detection signal and the furnace of the detection device are detected. A method for detecting the state of a metal strip running in a horizontal furnace, which is characterized by detecting the meandering amount, categorical amount and plate shape of the metal strip by the following operations (a) to (c) from the position signal in the width direction. Is. (B) The running center position of the metal belt is obtained from the detection signal when the detector passes through each edge of the metal belt and detects the hearth and the position signal in the furnace width direction of the detector, and the running center of the metal belt is obtained. The deviation between the position and the pass line center position is obtained as the amount of meandering of the metal strip. (B) A plurality of metal strip height values detected in one movement of the detector in the furnace width direction are averaged to obtain an average metal strip height, and the average metal strip height and the pass line height are calculated. The deviation is calculated as the amount of metal band catenary. (C) The metal band height values at a plurality of measurement points detected in one movement of the detector in the furnace width direction are averaged to obtain an average metal band height, and the average metal band height and The deviation from the height of the metal strip at the measurement point is determined, and the deviation at each measurement point is averaged over the number of times the detector moves, and the plate shape is based on the averaged deviation at each measurement point in the metal strip width direction. To detect.

[0007]

1 to 3 show an embodiment of the method of the present invention, in which 1 is a furnace body and 2 is a conveyer roll in the furnace. A slit 3 is formed along the furnace width direction in the upper part of the furnace body at a central position between the transfer rolls 2, and a detection device 4 is provided above the slit 3 so as to be movable in the slit longitudinal direction. In this embodiment, a cover a having a water cooling structure made of a transparent member is attached to the upper portion of the slit 3, and a purge gas (nitrogen gas) is supplied to the inside of the cover a to keep the inner surface of the cover clean. There is.

The detection device 4 has a laser oscillator 5 and a photodetector 6, so that the laser oscillator 5 irradiates the inside of the furnace through the slit 3 and the reflected light can be received by the photodetector 6. There is. This detection device 4 can detect the distance to the steel strip S or the hearth that passes through the furnace by detecting the image formation position of the laser light. Reference numeral 7 denotes a screw shaft 7 that holds the detecting device 4, and the screw shaft 7 is rotationally driven by a drive motor 8 and the rotation causes the detecting device 4 to rotate.
Moves along the slit 3. A position detector 9 (pulse generator) for detecting the position of the detector 4 in the furnace width direction is connected to the drive motor 8.

In the method of the present invention, the detector 4 is reciprocally moved along the slit 3, laser light is emitted from the laser oscillator 5 into the furnace during the movement, and the reflected light is detected by the light receiver 6. This detection signal and the position signal in the furnace width direction of the detection device 4 by the position detector 9 are sent to the arithmetic device 10 to detect the meandering amount, categorical amount and plate shape of the steel strip S.

This will be described with reference to FIGS. 4 and 5. The detector 4 irradiates and receives laser light at a plurality of measurement points during one movement in the furnace width direction, and the steel strip position by this is obtained. Further, from the detection of the height (distance) of the steel strip and the position detection of the detection device 4 by the position detector 9, the meandering amount, categorical amount and plate shape of the steel strip S are detected by the following calculation.

First, as shown in FIG. 4, the detection signals x ₂ and x ₃ when the detector 4 passes through each edge of the steel strip S and detects the hearth and the position signal of the detector in the furnace width direction are shown. from, prompts the steel strip traveling center position x _c, the steel strip traveling center position x _c
And the pass line center position x _p are determined as the meandering amount of the steel strip S. Further, a plurality of steel strip height values y _i detected in one movement of the detector 4 in the furnace width direction are averaged to obtain an average steel strip height y _c , and the average steel strip height y _c is calculated. The deviation between _c and the height of the pass line y _p is determined as the amount of catenary of the steel strip S.

Further, as shown in FIG. 5, a plurality of measurement points x detected in one movement of the detector 4 in the furnace width direction.
₁ ... The strip height values y at x _j are averaged, and this averaging process is performed for each of the k movements of the detector 4 in the strip width direction, and the average strip height mean− y ₁ ...... mean−
y _k is accumulated (I in the figure). This average strip height mean
-Y ₁ ... mean-y _k and the height y of the strip at each measurement point x ₁ ... x _j at each movement of k times are compared to obtain the deviation, and each measurement point x ₁ …… The deviation at x _j is the above k
The movements are averaged for the number of times, and the deviation λx ₁ ... λx _j is obtained (formula II in the figure). Then, the plate shape is detected based on the averaged deviations λx ₁ ... λx _j at the respective measurement points in the width direction of the steel strip. For example, it is determined that the portion where the deviation λx is large in the width direction of the steel strip has significant elongation.

[0013]

According to the present invention described above, the meandering amount, the catenary amount, and the plate shape of the metal strip running in the horizontal furnace are determined by moving the detecting device along the slit provided in the furnace body. At the same time, it can be detected regardless of the width size of the metal strip.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention in a state in which a furnace body is cross-sectioned.

FIG. 2 is an explanatory view showing an embodiment of the present invention in a state in which a furnace body is longitudinally sectioned.

FIG. 3 is an explanatory perspective view showing a detection situation by the detection device in the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a calculation processing flow in the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a calculation processing flow in the embodiment of the present invention.

FIG. 6 is an explanatory view showing a conventional method for detecting the meandering amount and the catenary amount of a steel strip in a state in which the furnace is cross-sectioned.

7 is an explanatory diagram showing detection positions in the conventional method shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Furnace body, 2 ... In-furnace conveyance roll, 3 ... Slit, 4 ... Detection device, 5 ... Laser transmitter, 6 ... Light receiver, 7 ... Screw shaft, 8 ... Drive motor, 9 ... Position detector, 10 ... Computing device, S ... Steel strip

Claims (1)

[Claims] 1. A detection device equipped with a laser oscillator and a light receiver is reciprocated along a slit provided in the width direction of the upper part of the furnace body at the central position between the in-furnace conveying rolls, and the laser of this moving detection device is moved. Laser light is emitted from the oscillator through the slit into the furnace, and the reflected light is detected by the light receiver. From this detection signal and the position signal in the furnace width direction of the detector, the following (a) to (c) A method for detecting the state of a metal strip running in a horizontal furnace, which comprises detecting the meandering amount, categorical amount and plate shape of the metal strip by calculation. (B) The running center position of the metal belt is obtained from the detection signal when the detector passes through each edge of the metal belt and detects the hearth and the position signal in the furnace width direction of the detector, and the running center of the metal belt is obtained. The deviation between the position and the pass line center position is obtained as the amount of meandering of the metal strip. (B) A plurality of metal strip height values detected in one movement of the detector in the furnace width direction are averaged to obtain an average metal strip height, and the average metal strip height and the pass line height are calculated. The deviation is calculated as the amount of metal band catenary. (C) The average metal band height is obtained by averaging the metal band height values at a plurality of measurement points detected in one movement of the detector in the furnace width direction, and the average metal band height and The deviation from the height of the metal strip at the measurement point is determined, and the deviation at each measurement point is averaged over the number of times the detector moves, and the plate shape is based on the averaged deviation at each measurement point in the metal strip width direction. To detect.