JPH07306096A - Method for measuring plate temperature in continuous heat treatment facility - Google Patents

Abstract

PURPOSE:To properly compensate only noise part by laying out thermometers while fully separating a downstream side in the direction for carrying a material to be treated and an upstream side and judging the generation and extinction of noise according to the change in the temperatures of plates measured by both thermometers. CONSTITUTION:It is judged that a noise is generated when the change of the temperature of a plate obtained by a first thermometer 2 at a downstream side becomes radical. On the other hand, it is judged that a noise was extinguished according to the change in the temperature of a plate by a second thermometer 3 for the upstream side from a part where noise occurs at the material to be treated, thus utilizing that a state without a drastic change in the temperature of the plate by the second thermometer 3 continues at the same time when the drastic change in the temperature of the plate by the first thermometer 2 disappears and hence instantly judging that noise is extinguished when the drastic change in the temperature of the plate by the first thermometer 2 disappears.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate in a continuous heat treatment facility for measuring a surface temperature (hereinafter, referred to as a plate temperature) of a material to be processed conveyed in a continuous heat treatment furnace of an iron mill or an aluminum manufacturing plant. Regarding temperature measurement method. The present invention is suitable for measuring the temperature of a material to be treated (hereinafter, referred to as a thin steel plate or a strip) in a continuous annealing facility (CAL) of an iron mill, and therefore will be described below as an example.

[0002]

2. Description of the Related Art A continuous annealing facility welds a tail end of a thin steel sheet wound in a coil shape and a leading end of a thin steel sheet following the welding, and anneales them while continuously conveying them as a series of strips in an annealing furnace. It is a facility for processing. In this continuous annealing, it is necessary to control the annealing treatment temperature within the upper and lower limits of the target temperature, which differs depending on the type of product, and for that purpose the plate temperature must be measured accurately.

Generally, in measuring the temperature of a thin steel sheet, a monochromatic radiation thermometer is used which assumes that the emissivity is constant. However, with this method using a monochromatic radiation thermometer, there is a portion of the surface of the thin steel sheet to be measured that significantly changes the emissivity, such as a welded part, or the thin steel sheet is meandering. When the measurement spot of the thermometer is significantly deviated from the center of the thin steel sheet, a large noise is generated in the temperature measurement value at that portion. FIG. 1 shows a typical example.

Controlling the plate temperature based on the temperature measurement value containing such noise may cause an erroneous control operation. In order to prevent such a situation, it is necessary to perform a correction process on the noise and obtain an appropriate correction value by removing the noise. A moving average method is known as a general method of correcting noise. The input value is the time-series data of the plate temperature shown in FIG. 2A, the input value is subjected to a correction process based on the definition of the moving average method, and the output value obtained by removing the noise (FIG. 2B). See)).

[0005]

However, in the moving average method, since the plate temperature measurement value around the plate temperature measurement value that needs to be corrected is used as the input data, the effect of noise is sufficiently reduced when the number of input data is reduced. Cannot be removed,
On the other hand, if the number of input data is large, the influence of noise can be reduced, but since the influence of input data is largely reflected in the corrected plate temperature, it is difficult to recognize the fluctuation of the actual measured value of plate temperature that is not noise. . That is, the degree of correction of the plate temperature measurement value to be corrected is highly dependent on the time-series input data, does not impair the actual variation of the plate temperature measurement value, and obtains an appropriate correction value. Is difficult.

In view of the above problems, the present invention recognizes a noise portion from the plate temperature measurement value, corrects only the noise portion, and affects the plate temperature measurement value other than the noise portion by the correction process. It is an object of the present invention to provide a plate temperature measuring method in a continuous annealing equipment that can obtain an appropriate correction value in real time without giving it.

[0007]

According to a first aspect of the present invention, there is provided a plate temperature measuring method in a continuous heat treatment equipment for measuring a surface temperature of a material to be processed conveyed in a continuous heat treatment furnace,
A noise occurrence recognition step of recognizing the occurrence of noise based on the plate temperature measurement value measured by the first thermometer;
Noise erasure that recognizes the disappearance of the noise based on the plate temperature measurement value of the upstream side of the noise occurrence point of the material to be processed, which is measured by the second thermometer provided upstream of the thermometer in the direction of conveyance of the material to be processed It is characterized by comprising a recognition step and a plate temperature correction processing step of performing a correction process for removing the noise on the measured value of the plate temperature of the portion where the noise is generated for a predetermined period after the noise is generated.

According to a second aspect of the present invention, in the noise generation recognizing step according to the first aspect, if the latest inclinations of the plurality of sheet temperature measurement values by the first thermometer are equal to or more than a predetermined threshold value, the noise is detected. The noise extinction recognition step is configured to recognize that the latest plurality of points of the plate temperature measurement value by the first thermometer are less than a predetermined threshold value, and the second thermometer. It is characterized in that it is configured to recognize that the noise disappears if the inclinations of the plurality of measured values of the plate temperature due to are less than a predetermined threshold value.

[0009]

As shown in the typical example in FIG. 1, noise shows a steep rise that is not seen in normal plate temperature changes. Therefore, it is necessary to recognize the occurrence of noise by using the latest measured value of plate temperature obtained by an appropriate numerical analysis method. It can be instantly judged by the change degree (slope) of several points at the maximum. However, the disappearance of noise is determined by the fact that the plate temperature does not largely change and the stable state continues, and therefore some elapsed time is required and cannot be determined instantaneously.

On the other hand, in the present invention, the first thermometer is arranged on the downstream side in the steel sheet conveying direction, and the second thermometer is arranged on the upstream side with a sufficient distance from each other. Since the occurrence and disappearance of noise is determined, not only the occurrence of noise but also disappearance can be instantly recognized. That is, regarding the occurrence of noise, it may be determined that the noise occurs when the change in the plate temperature measurement value by the first thermometer becomes sharp. On the other hand, for the disappearance of noise, since the change in the plate temperature measurement value of the second thermometer in the upstream side of the noise generation part of the material to be processed is used, the plate temperature measurement value of the first thermometer is used. It is possible to utilize that the plate temperature measurement value of the second thermometer continues to have no large change at the same time when the large change of the first thermometer disappears. It can be judged instantly when there is no significant change in the measured value of the plate temperature.

As described above, according to the present invention, two plate temperature measuring thermometers are provided at intervals in the conveying direction of the material to be processed, and the change of the plate temperature measurement value by the first thermometer installed downstream in the conveying direction. Since the occurrence of noise is determined based on the change in the plate temperature measurement value and the change in the plate temperature measurement value by the second thermometer installed upstream in the transport direction, the noise disappearance is determined. Occurrence and disappearance can be instantly recognized, correction processing can be performed only on the noise portion, and an appropriate correction value can be obtained in real time without affecting the plate temperature measurement value other than the noise portion due to the correction processing. .

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 3 to 5 are views for explaining a plate temperature measuring method of a continuous annealing equipment according to an embodiment of the present invention, and FIG. 3 is a configuration diagram of a continuous annealing furnace for carrying out the method of the present embodiment, FIG. 4 is a flowchart showing the processing procedure of the method of this embodiment, and FIG. 5 is a diagram for explaining the generation and disappearance of noise.

In FIG. 3, reference numeral 1 is a continuous annealing furnace (CAL).
, A heating zone is shown, and a large number of conveying rollers 1b are arranged above and below the furnace body 1a. Each roller 1
The thin steel plate 5 is stretched between b ... and is heat-treated while being conveyed in the direction of the arrow in the figure. The transport speed (line speed) of the thin steel plate 5 is obtained from the rotation speed and the roll diameter of the drive roll arranged outside the heating furnace for a certain period of time.

On the top wall of the furnace body 1a, there is a thin steel plate 5
Two monochromatic radiation thermometers for measuring the surface temperature of the sheet are arranged at two positions sufficiently separated from each other in the sheet steel conveyance direction.
The first thermometer arranged on the downstream side in the steel sheet conveying direction is the temperature control thermometer 2, and the second thermometer arranged on the upstream side is the plate temperature correcting thermometer 3.

Reference numeral 4 denotes a control device for controlling the operation of the continuous annealing furnace 1 of the present embodiment. The control device 4 controls the temperature values of the control and correction thermometers 2 and 3 and the speedometer 6 of the speedometer 6. The line speed is read at regular intervals (t), and various controls for performing heat treatment along the target heat treatment curve are performed based on the input value. In the measurement of the plate temperature, the control device 4 recognizes the occurrence of noise from the change in the plate temperature measurement value from the control thermometer (first thermometer) 2 and determines the plate temperature measurement value of the thermometer 2. Of the noise and the change of the plate temperature measurement value of the correction thermometer (second thermometer), the noise disappearance is recognized, and the plate temperature measurement value measured from the time when the noise is generated to the time when the noise disappears is predetermined. Correction processing is performed.

The process of recognizing the occurrence and disappearance of the noise and the process of correcting the noise will be described with reference to FIGS. 4 and 5. FIG. 5 (a) shows the plate temperature measurement values by the control and correction thermometers 2 and 3 at constant intervals t, and FIG. 5 (b) shows the relationship between the thin steel plate 5 and the thermometers 2 and 3. Shown respectively. In the figure, X indicates a noise occurrence site, and a to e indicate plate temperature measurement sites. The noise generation site X passes directly below the upstream thermometer 3 from time t3 to t5, and from time t7 to t.
In FIG. 9, it is assumed that it passes directly below the downstream thermometer 2.

As described above, the line speed is constantly input to the control device 4, and the measured values of the plate temperature from the plate temperature control thermometers 2 and the correction thermometers 3 are set at constant intervals t. For example, as shown in FIG. 5, it is input at times t1, t2 ... T11. The portion measured by the upstream thermometer 3 is measured by the downstream thermometer 2 after four cycles.

First, whether there is noise in the plate temperature measured by the plate temperature controlling thermometer (first thermometer) 2 one cycle before the current measurement time in step S1 by the control device 4 described above. Is judged. If no noise is present in the plate temperature, it is determined in step S2 whether or not noise is generated according to the current degree of change (steepness) of the plate temperature.

The steepness of the change of the plate temperature is judged in the following manner. Regarding the plate temperature measured by the plate temperature control thermometer 2 for each cycle t, two-point gradient gra between the latest measured value and the measured value one cycle before is obtained according to the following equation. grad = (Tsn-Tso) / t where Tsn: the latest plate temperature measured by the plate temperature control thermometer 2 Tso: plate temperature one cycle before measured by the plate temperature control thermometer 2 and the slope gra The absolute value is compared with a threshold value TH1 prepared in advance, and if the absolute value of the slope is equal to or more than the threshold value, it is recognized that noise has occurred (beginning), and if it is less than the threshold value, noise is detected. Recognized as a nonexistent plate temperature measurement.

As shown in FIG. 1, the recognition of the occurrence of noise shows a steep rise which is not seen in the normal change of the plate temperature, so that it can be easily judged by catching this change by the above method. For example, at time t7 in FIG. 5, the absolute value of the slope between the plate temperature at time t7 and the plate temperature at time t6 one cycle before becomes equal to or greater than the threshold value, and the occurrence of noise is recognized (step S3). The correction process is performed in step S4.

It is assumed that the above correction process changes from the measured value one cycle before (time t6) with the inclination of the plate temperature at several points (for example, time t5, t4, t3) immediately before noise.
This is performed by correcting the plate temperature measurement value at time t7 and setting this as the actual plate temperature measurement value.

If the inclination is less than the threshold value in the step S2, it is recognized as a plate temperature measurement value in which noise is not generated (step S5), and the correction process (S4) is not performed, and the normal plate temperature in the next cycle is performed. Is measured.

If it is determined in the step S1 that there is noise in the measured value of the plate temperature one cycle before, it is determined in step S6 whether or not the degree of change in the plate temperature has become gentle. It is determined in the same manner as described above, and when it is not moderate, it is recognized that noise is continuing, and the correction process is performed by the same method as in step S4 (steps S7 and S8).

The recognition of the disappearance of noise is performed when the following conditions 1 to 4 are satisfied. First, in step S1, it is determined that the plate temperature measurement value obtained by the control thermometer 2 one cycle before has noise (in the case of time t10 in FIG. 5), and then in step S6, the plate temperature gradient gra is determined. Since it is less than the threshold value TH1, it is determined that the change in plate temperature has become gradual (time t11), and step S
When the following conditions are satisfied in 9, it is recognized that the noise has disappeared.

That is, the portion of the thin steel plate measured by the plate temperature control thermometer 2 at time t11 (time t1 in FIG. 5B).
1-line-shaped part a) is a plate temperature measurement value of the correction thermometer 3 at a time point (time t7) immediately below the correction thermometer 3 and upstream of the part a. Location b
~ E plate temperature measurement value by the correction thermometer 3 (time t8 ~ t
When the degree of change locus (measurement value at 11 points) (absolute value of inclination) is gentle, noise disappearance is recognized.

Here, the gradient gra 'of the change locus is obtained by the following equation. grad ′ = (Tt11 −Tt7) / 4t where Tt11: latest (time t11) plate temperature measured by the plate temperature correction thermometer 3 Tt7: 4 cycles before (time at the plate temperature correction thermometer 3
When the plate temperature of t7) and the above conditions (1) to (4) are satisfied, it is recognized that the noise disappears (step S10), and the correction processing for removing the noise is interrupted until the generation of the noise is newly recognized. The plate temperature measurement including the series of correction processes for removing noise is performed until the annealing process of the thin steel plate is completed.

The present invention is not limited to the above-mentioned embodiment, but various modifications are possible. Further, as a method of recognizing the disappearance of noise, a method of judging only from the plate temperature measurement value from one thermometer can be considered. For example, if the absolute value of the difference between the immediately preceding plate temperature measurement value of the recognized noise and the latest plate temperature measurement value is less than the predetermined threshold value TH3 after simultaneously satisfying the conditions in the above embodiment. Also, it is possible to develop applications such as recognizing that noise has disappeared.

[0028]

According to the plate temperature measuring method in the continuous heat treatment equipment of the first aspect of the present invention, two plate temperature measuring thermometers are provided at intervals in the carrying direction of the material to be processed, and the thermometers are provided downstream in the carrying direction. The occurrence of noise is judged from the change in the plate temperature measurement value by the installed first thermometer, and both the change in the plate temperature measurement value and the change in the plate temperature measurement value by the second thermometer installed upstream in the conveying direction. Since the disappearance of the noise is determined from the above, it is possible to instantly determine the occurrence and disappearance of the noise, and it is possible to perform the correction processing only on the noise portion, and the effect of the correction processing on the plate temperature measurement value other than the noise portion is affected. It is possible to obtain an appropriate correction value in real time without giving it, and there is an effect that the accuracy of the plate temperature automatic control in the actual operation can be improved.

According to the second aspect of the invention, if the latest inclinations of the plate temperature measured by the first thermometer are more than a predetermined threshold value, it is recognized that noise has occurred, and the inclination is predetermined. Is less than the threshold value and the slopes of the multiple values of the plate temperature measured by the second thermometer are less than the predetermined threshold value, it is recognized that the noise disappears. There is an effect that an instant recognition method can be provided more specifically.

[Brief description of drawings]

FIG. 1 is a diagram showing a typical example of noise in plate temperature measurement.

FIG. 2 is a diagram for explaining a conventional noise correction processing method.

FIG. 3 is a schematic view of a continuous annealing furnace for carrying out a plate temperature measuring method according to an embodiment of the present invention.

FIG. 4 is a flow chart for explaining the method of the above embodiment.

FIG. 5 is a diagram for explaining the method of the embodiment.

[Explanation of symbols]

 1 Continuous Annealing Furnace (Continuous Heat Treatment Furnace) 2 Plate Temperature Control Thermometer (1st Thermometer) 3 Plate Temperature Correction Thermometer (2nd Thermometer) 4 Plate Temperature Control Calculator 5 Thin Steel Plate (Workpiece)

Claims (2)

[Claims] 1. A method of measuring plate temperature in a continuous heat treatment facility for measuring the temperature of a material to be processed conveyed in a continuous heat treatment furnace, comprising: measuring a noise of a noise based on a plate temperature measurement value measured by a first thermometer. Noise generation recognition step for recognizing generation, and plate temperature measurement of a portion upstream of the noise generation portion of the processed material measured by a second thermometer provided upstream of the first thermometer in the processing material conveyance direction A noise disappearance recognition step of recognizing the disappearance of the noise based on a value, and a plate temperature correction processing step of performing a correction process of removing the noise on the measured value of the plate temperature of the noise occurrence portion for a predetermined period after the noise occurrence. And a plate temperature measuring method in a continuous heat treatment facility. 2. The noise generation recognizing step according to claim 1, wherein the noise is recognized if the latest inclinations of the plurality of plate temperature measurement values by the first thermometer have a predetermined threshold value or more. In the noise disappearance recognition step, the latest inclinations of the plate temperature measured value by the first thermometer are less than a predetermined threshold, and the plate temperature measured value by the second thermometer is configured. A method for measuring plate temperature in a continuous heat treatment facility, wherein: if the inclination of a plurality of points is less than a predetermined threshold value, it is recognized that noise disappears.