JP2022156276A - Device for measuring metal sheet surface temperature, annealing equipment, and method for measuring surface temperature - Google Patents

Abstract

To provide a device for measuring metal sheet surface temperature, annealing equipment, and a method for measuring surface temperature that is capable of simply and accurately measuring the temperature of a metal sheet in a straight pass between rolls where the metal sheet is not wound around the rolls.SOLUTION: A device 1 for measuring metal sheet surface temperature is for measuring metal sheet surface temperature in a straight pass between rolls. The device 1 includes a first radiation measuring mechanism 10 for measuring the radiance or temperature of a surface on a roll 3B side of a metal sheet of a wedge formed by the metal sheet and the roll 3B that changes the orientation of the metal sheet, a second radiation measuring mechanism 11 for measuring the radiance or temperature of a surface on the opposite side of the roll 3B of the metal sheet of the wedge, an emissivity calculation mechanism 12 for calculating emissivity from the radiance or temperature measured by the first radiation measuring mechanism 10 and the radiance or temperature measured by the second radiation measuring mechanism 11, and an emissivity calculation mechanism 13 for measuring the temperature of the surface of the metal sheet by using the calculated emissivity.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a surface temperature measuring device, annealing equipment, and surface temperature measuring method for a metal plate that is continuously conveyed via rolls.

In the process of manufacturing metal sheets, especially in the process of manufacturing thin steel sheets in the steel industry, temperature control is very important from the viewpoint of building materials. Especially in the annealing process, there is a need to measure the surface temperature of the steel sheet during transportation in order to control the temperature of the steel sheet so that it reaches the target temperature in each process. A representative temperature measurement method is radiation thermometry, which measures the radiance of an object and converts it into temperature. However, in radiation thermometry, the temperature cannot be measured correctly unless the emissivity of the object is known. If the surface properties of the object to be measured change greatly during the manufacturing process, there is a problem in setting the emissivity. there is

As a method that can measure temperature regardless of the emissivity of the object, as in Patent Document 1, a slight gap between the roll 80 and the surface of the steel plate 81 is set as a field of view of the radiation thermometer 82 to simulate multiple reflection conditions. A multi-reflection radiation thermometer system (see, for example, FIG. 1) capable of measuring temperature with an emissivity approaching 1.0 is disclosed. In addition, as in Non-Patent Document 1, a thermocouple 84 is embedded in a hollow roll 83, and a temperature measurement roll that measures the temperature by creating a condition where the temperatures of the thermocouple 84 and the steel plate 85 are the same at the portion where the steel plate is wound. A scheme (see, eg, FIG. 2) is disclosed. Furthermore, as in Patent Document 2, a spectral principal component radiation thermometer using target spectral radiation and learning by principal component analysis is also disclosed.

JP-A-60-78327 JP 2014-202528 A

Tetsu to Hagane 79(7), 765-771, 1993

The methods of Patent Document 1 and Non-Patent Document 1 are very powerful methods for correctly measuring the target steel plate temperature, but cannot be used unless the roll surface and the target plate temperature are the same. should be sufficiently wrapped around the Therefore, it cannot be used under straight pass conditions between rolls in which the thin steel sheet is not wound around the rolls. Moreover, the method of Patent Document 2 has problems such as a need for a contact-type thermocouple in order to obtain the true temperature value, which makes the device large-scale, and a large amount of data required for learning.

However, even in the straight pass between rolls, there are processes that are very important for temperature control, such as immediately before a sudden temperature change, and there is a strong need for temperature measurement. In particular, the steel sheet temperature immediately before water quenching is extremely important in terms of quality, but it is difficult to place a roll just before the water quenching due to equipment restrictions, and temperature measurement using rolls cannot be applied.
Conventionally, as a method for measuring the temperature of a steel plate in a straight path, a contact-type temperature measurement method or a radiation temperature measurement method assuming that the emissivity of the steel plate is a certain value has been used. However, the contact-type temperature measurement method cannot avoid scratches on the surface of the steel sheet, and there is a problem in the accuracy of the radiation temperature measurement assuming the emissivity.
In view of the above circumstances, the present invention proposes a method for simply and accurately measuring temperature in a straight path between rolls that are not wound around rolls.

Therefore, the present invention has been made focusing on the above problems, and the temperature of the metal plate can be easily and accurately measured in a straight path between rolls in which the metal plate is not wound around the rolls. An object of the present invention is to provide a surface temperature measuring device, annealing equipment, and surface temperature measuring method for a metal plate.

According to one aspect of the present invention, there is provided a metal plate surface temperature measuring device for measuring the surface temperature of a metal plate in a linear path between rolls, the device being formed by a roll for changing the orientation of the metal plate and the metal plate. a first radiation measuring mechanism for measuring the radiance or temperature of the roll side surface of the metal plate of the wedge portion, and the radiance or temperature of the wedge portion on the surface opposite to the roll of the metal plate Radiation for calculating emissivity from a second radiation measurement mechanism for measuring temperature, radiance or temperature measured by the first radiation measurement mechanism, and radiance or temperature measured by the second radiation measurement mechanism A surface temperature measuring device for a metal plate is provided, comprising a rate computing mechanism and a radiation temperature measuring mechanism for measuring the temperature of the surface of the metal plate using the calculated emissivity.
According to one aspect of the present invention, there is provided a metal plate annealing facility having the above-described surface temperature measuring device.

According to one aspect of the present invention, there is provided a method for measuring the surface temperature of a metal plate in a linear pass between rolls, the method being formed by rolls that change the orientation of the metal plate and the metal plate. Measure the radiance or temperature of the wedge portion on the surface of the metal plate on the roll side, measure the radiance or temperature of the wedge portion on the surface of the metal plate opposite to the roll, and measure Emissivity is calculated from the measured radiance or temperature of the surface on the roll side and the measured radiance or temperature of the surface opposite to the roll, and using the calculated emissivity, the metal A method for measuring the surface temperature of a metal plate is provided, which measures the temperature of the surface of the plate.

ADVANTAGE OF THE INVENTION According to one aspect of the present invention, a surface temperature measuring device for a metal plate and an annealing facility capable of easily and accurately measuring the temperature of the metal plate in a straight pass between rolls in which the metal plate is not wound around the rolls. and a surface temperature measurement method are provided.

FIG. 4 is an explanatory diagram showing a temperature measurement method using a multiple reflection radiation thermometer system; FIG. 4 is an explanatory diagram showing a temperature measuring method using a temperature measuring roll system; BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the surface temperature measuring apparatus of the metal plate which concerns on one Embodiment of this invention. It is a graph which shows an example of a calibration result. FIG. 4 is a schematic diagram showing an example of using one radiation thermometer as the first radiation measurement mechanism and the radiation temperature measurement mechanism; It is a schematic diagram which shows the control mechanism using a temperature adjustment apparatus. It is a graph which shows the temperature measurement result in an Example.

The following detailed description describes embodiments of the invention with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals, and overlapping descriptions are omitted. Each drawing is schematic and may differ from the actual one. In addition, the embodiments shown below are examples of apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material, structure, arrangement, etc. of component parts. It is not specific to the following. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

<Surface temperature measuring device for metal plate>
A surface temperature measuring device 1 for a metal plate according to an embodiment of the present invention will be described. In the present embodiment, a thin steel plate 2, which is a steel plate, is used as an example of a metal plate, and the general outline of the surface temperature measuring device 1 will be described with reference to FIG.
In the manufacturing process of the thin steel sheet 2, the material is often refined by quenching after annealing, but there is only a straight path before this quenching. In the annealing process shown in FIG. 3, the thin steel sheet 2 that has passed through the rolls 3A and 3B is then conveyed to the next roll (not shown) in a straight path (conveyance path parallel to the vertical direction in FIG. 3). pass through In this straight pass, the thin steel plate 2 is rapidly heated or rapidly heated in the heat treatment device 4 . Further, in the straight path, the area on the upstream side of the transport path from the heat treatment apparatus 4 is called a temperature change zone 5 . Note that the temperature change zone 5 may be provided with a temperature adjustment device (not shown) for adjusting the temperature of the thin steel plate 2 conveyed to the heat treatment device 4 .

A surface temperature measuring device 1 is provided in an annealing facility for thin steel plates 2 and includes a first radiation measuring mechanism 10 , a second radiation measuring mechanism 11 , an emissivity computing mechanism 12 , and a radiation temperature measuring mechanism 13 .
The first radiation measuring mechanism 10 is a roll at a roll winding position immediately before the linear pass, and is a wedge portion roll formed by the thin steel plate 2 and the roll 3B that changes the direction of the thin steel plate 2 immediately before the linear pass. The radiance or temperature of the thin steel plate 2 on the side of 3B is measured. The first radiation measurement mechanism 10 is configured by, for example, a radiation thermometer. The wedge portion is a wedge-shaped region where the roll 3B and the thin steel plate 2 are adjacent to each other, just before the position where the roll 3B and the thin steel plate 2 contact each other. The first radiation measuring mechanism 10 is provided on the roll 3B side of the thin steel plate 2 so as to look at this wedge portion.

The second radiation measuring mechanism 11 measures the radiance or temperature of the surface of the thin steel plate 2 of the wedge portion opposite to the roll 3B. In this embodiment, the second radiation measuring mechanism 11 is provided on the side of the thin steel plate 2 opposite to the roll 3B, and measures the temperature or brightness of the surface of the thin steel plate 2 on the side where it is provided. The second radiation measurement mechanism 11 is composed of, for example, a radiation thermometer. In addition, in the measurement by the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11, it is preferable to measure the tip side of the wedge portion.
The emissivity calculation mechanism 12 calculates the emissivity based on the radiance or temperature measured by the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11 . A method of calculating the emissivity by the emissivity calculation mechanism 12 will be described later.

The radiation temperature measuring mechanism 13 is provided immediately before the heat treatment device 4, and uses the emissivity calculated by the emissivity calculating mechanism 12 to measure the temperature of the surface of the thin steel plate 2 moving in a straight path. The radiation temperature measuring mechanism 13 is provided downstream of the temperature change zone 5 in the conveying direction. Moreover, the radiation temperature measuring mechanism 13 preferably measures the temperature of the surface of the thin steel plate 2 on the side where the second radiation measuring mechanism 11 measures the radiance or temperature. The radiation temperature measuring mechanism 13 is composed of, for example, a radiation thermometer.
Here, the emissivity of the second radiation measuring mechanism 11 and the radiation temperature measuring mechanism 13 preferably have the same wavelength characteristic in order to have wavelength dependence. Moreover, it is preferable that the surface properties of the thin steel plate 2 to be measured do not change as much as possible between the installation position of the second radiation measurement mechanism 11 and the installation position of the radiation temperature measurement mechanism 13 .

<Method for measuring surface temperature of metal plate>
In such a surface temperature measuring device 1, the emissivity calculating mechanism 12 calculates the emissivity from the radiance or temperature obtained by the first radiation measuring mechanism 10 and the second radiation measuring mechanism 11, and the radiation temperature measuring mechanism 13 Radiation temperature measurement is performed by the radiation temperature measurement mechanism 13 using the emissivity calculated at the time of temperature measurement.
Then, the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11 output temperature measurement results or luminance values according to their specifications.

(Output of temperature measurement results)
A case where the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11 output temperature measurement results will be described. When outputting the temperature measurement result, the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11 are set to have a certain emissivity, and the temperature is measured. This emissivity may be any known value, but the emissivity of the first radiation measuring mechanism 10 and the second radiation measuring mechanism 11 is assumed to be 1.0 for convenience. The radiation temperature of the first radiation measuring mechanism 10 thus obtained is _Tr , and the radiation temperature of the second radiation measuring mechanism 11 is _TA . In order to calculate the emissivity, it is necessary to compare the actual radiance with the radiance (black body radiance) when the emissivity is 1.0 (blackbody condition). Therefore, it is necessary to convert the obtained temperature value into a luminance value, and the conversion formula is calculated in advance by calibration before installing the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11 . The equation used for calibration may be a general polynomial equation, but if accuracy is to be sought, Sakuma Hattori's equation (equation (1) below), which closely approximates Planck's equation, is preferable. Hattori's formula is used (Transactions of the Society of Instrument and Control Engineers, 18(7), 704-709, (1982)). A method for calibrating a thermometer is described in "JIS C 1612 General Rules for Performance Test Methods for Radiation Measurement Mechanisms", and an example of calibration results using this calibration method is shown in FIG. At this time, parameters A, B, and C unique to the radiation measuring mechanism are obtained, and the emissivity is calculated using these parameters. In equation (1), _C2 is the second Planck's constant, and V is the output voltage (V) in the radiation measurement mechanism.

Equations (2) and (3) show the results of converting T _r and T _A into radiances S _r and S _A using Equation (1). Since the emissivity ε is the ratio of the radiance Sr under the black body condition to the actual _radiance S _A , it can be calculated by the equation (4). That is, in the present embodiment, the blackbody radiance corresponding to the temperature measured by the second radiation measurement mechanism 11 is calculated from the previously calculated relationship between the blackbody radiance and the temperature. Then, the emissivity ε is calculated by using the black body radiance calculated according to the temperature as the radiance measured by the second radiation measurement mechanism 11 .

In the present embodiment, conversion between temperature and radiance is performed using Sakuma Hattori's equation, but similar results can be obtained using other equations. Which formula should be selected for the conversion between temperature and radiance should be selected in consideration of the amount of calculation, accuracy, and wavelength characteristics of the radiation measurement mechanism. Further, the conversion between temperature and radiance described above may be performed by the emissivity calculation mechanism 12, or may be performed by the first radiation measurement mechanism 10 and the second radiation measurement mechanism 11, respectively.

(output of luminance value)
Next, the case where the second radiation measuring mechanism 11 outputs the radiance _SA will be described. In this case, since it is not necessary to convert the temperature value T _A to the radiance S _A by the equation (3), the same result can be obtained by directly substituting the output result S _A for S _A in the equation (4). be done. The same applies when the first radiation measurement mechanism 10 directly outputs the radiance _Sr. That is, the emissivity ε is calculated as the ratio (S _A /S _r ) of the radiance S _A measured by the second radiation measurement mechanism 11 to the radiance S _r measured by the first radiation measurement mechanism 10 . .
Using the emissivity ε obtained in this way, the temperature is measured by the radiation temperature measuring mechanism 13, and the temperature _Tb at the measurement position can be obtained.

Regarding the first radiation measuring mechanism 10 and the radiation temperature measuring mechanism 13, there is a problem that the equipment is large and the introduction and maintenance costs are high. Therefore, as shown in FIG. 5, one radiation thermometer 14 having a long longitudinal field of view may be used as the first radiation measurement mechanism 10 and the radiation temperature measurement mechanism 13 . In this case, among the temperature measurement results of the radiation thermometer 14, the location (14a in FIG. 5) with the maximum brightness or the maximum temperature is the measurement result of the first radiation measurement mechanism 10, and the stable location (14a in FIG. 5) of the thin steel plate 2 is By using the luminance or temperature of 14b) as the measurement result of the radiation thermometry mechanism 13, the equipment can be simplified.
The first radiation measuring mechanism 10 must be precisely adjusted to ensure that the wedge between the roll 3 and the thin steel plate 2 is in the field of view. However, this embodiment also has the advantage that it is easy to adjust, and even if the alignment changes during operation, any element in the longitudinal direction will serve as a wedge, improving robustness.

Since the position of the radiation temperature measuring mechanism 13 is preferably different from the positions of the second radiation measuring mechanism 11 and the roll 3B whose temperature is to be measured, it is better to align these measurement positions. For example, when the conveying speed of the thin steel plate 2 is v (m/s) and the distance between the two radiation measuring mechanisms is L (m), the timing at which the same point of the thin steel plate 2 passes both positions is L/ There is a delay of v(s). Therefore, it is preferable to use the emissivity before L/v(s) in the radiation temperature measuring mechanism 13 . Further, when the position on the thin steel plate 2 is tracked by the number of revolutions of the roll 3B, alignment may be performed from the tracking information. That is, in this alignment, the radiation used for measurement by the radiation temperature measuring mechanism 13 is determined based on the positional relationship between the second radiation measuring mechanism 11 and the radiation temperature measuring mechanism 13 and the conveying speed of the metal plate or the number of rotations of the rolls. rate is determined. At this time, the emissivity is determined so that the surface position of the thin steel plate 2 whose emissivity is calculated and the surface position of the thin steel plate 2 measured by the radiation temperature measuring mechanism 13 are the same. The alignment can be performed by the emissivity calculation mechanism 12, the radiation temperature measurement mechanism 13, or another calculation mechanism (not shown).

Further, in the present embodiment, the radiation temperature measuring mechanism 13 exists downstream of the second radiation measuring mechanism 11 and the rolls, but the radiation temperature measuring mechanism 13 exists upstream of the second radiation measuring mechanism 11 and the rolls. A similar temperature measurement is also possible. However, in this case, the emissivity of the radiation temperature measuring mechanism 13 is obtained after passing through the second radiation measuring mechanism 11. It is necessary to devise a method such as acquiring the luminance in advance and then converting it into a correct temperature measurement result using the emissivity obtained later. In this case as well, it is desirable to perform the above-described alignment.

Furthermore, as shown in FIG. 6, temperature control in many facilities measures the temperature of the thin steel plate 2 with the radiation temperature measuring mechanism 13, and the difference from the target temperature is measured in the previous process of the thermometer installation position (upstream side in the conveying direction). ) is controlled by feedback to the output of the temperature adjustment device 6 at . The temperature control device 6 heats or cools the thin steel plate 2 . A controller 7 controls the temperature adjustment device 6 based on the measurement result of the radiation temperature measuring mechanism 13 . However, in the feedback control, the gain of the controller 7 is manipulated after actually measuring the plate temperature, so the responsiveness inevitably decreases compared to the feedforward control. A decrease in responsiveness leads to an increase in the temperature failure region before and after the plate having different manufacturing conditions such as temperature and plate thickness, thereby lowering the yield.

In order to improve the responsiveness, feedforward control based on temperature prediction is necessary, but in the high temperature range, radiation as described in equation (5) is dominant in heat transfer, and emissivity is particularly important. In equation (5), E is the total energy of radiation, c1 is the _first Planck constant, λ is the wavelength, and σ is the Stefan Boltzmann constant.

In this embodiment, correct estimation of the emissivity improves control of the heat transfer model, and introduction of feedforward control enables control of the target plate temperature with high responsiveness. Also, feedforward control and feedback control may be combined to achieve more precise control.
Furthermore, the radiation thermometry mechanism 13 that actually measures the temperature may have a field of view in the width direction. Specifically, a line scan sensor, an area scan sensor, or the like that scans the field of view can be used. The line scan sensor and area scan sensor described here refer to sensors that have a one-dimensional or two-dimensional arrangement of light receiving sections and can acquire one-dimensional temperature distribution and two-dimensional temperature distribution in a single imaging. .

<Modification>
Although the invention has been described with reference to particular embodiments, it is not intended that the invention be limited by these descriptions. Along with the disclosed embodiments, other embodiments of the invention, including various modifications, will be apparent to persons skilled in the relevant art(s) upon reference to the description of the invention. Therefore, the embodiments of the invention set forth in the claims should be construed to cover the embodiments that include these variations described herein singly or in combination.

For example, in the above embodiment, the thin steel plate 2, which is a steel plate, is described as an example of the metal plate, but the present invention is not limited to this example. The metal plate is not limited to a steel plate, and may be a plate made of other metals.
Further, in the above embodiment, in the example shown in FIG. 3, the wedge portion to be measured is the wedge portion on the upstream side in the conveying direction of the thin steel plate 2 in the roll 3B, but the present invention is not limited to such an example. . The wedge portion to be measured may be the wedge portion on the downstream side of the roll 3B in the conveying direction of the thin steel plate 2 .
Furthermore, in the above embodiment, the surface temperature device 1 is provided in the annealing equipment for the thin steel plate 2, but the present invention is not limited to such an example. The surface temperature device 1 can be applied to other equipment as long as the metal plate such as the thin steel plate 2 is conveyed in a straight pass between rolls and one of the rolls forming the straight pass changes the direction of the metal plate. be able to.

An example conducted by the present inventors will be described. In the example, the arrangement of the apparatus was the same as that shown in FIG. First, the second radiation measurement mechanism 11 was calibrated in advance. Next, the emissivity was calculated from the measurement results of the second radiation measurement mechanism 11 and the first radiation measurement mechanism 10 . Sakuma-Hattori's formula was used for the emissivity calculation model. At this time, since the positions of the second radiation measuring mechanism 11 and the radiation temperature measuring mechanism 13 were separated by about 30 m, the conveying speed (sheet threading speed) v (m/s) was constantly obtained from the roll 3, and 30/v ( s) The previous emissivity was used when calculating the temperature of the radiation thermometer 13;
FIG. 7 shows the results of temperature measurement. It was confirmed that the temperature of the metal plate can be measured even between the rolls where the metal plate is not wound around the roll 3 by constantly correcting the emissivity fluctuation. That is, by using the evaluation technique of the present invention, it becomes possible to measure temperature with correct emissivity in a vertical pass between rolls as described in the examples.

1 Surface Temperature Measuring Device 10 First Radiation Measuring Mechanism 11 Second Radiation Measuring Mechanism 12 Emissivity Calculating Mechanism 13 Radiation Temperature Measuring Mechanism 14 Radiation Thermometer 2 Thin Steel Plates 3, 3A, 3B Roll 4 Heat Treatment Apparatus 5 Temperature Change Zone 6 Temperature Adjustment Apparatus 7 controller 80, 83 rolls 81, 85 steel plate 82 radiation thermometer 84 thermocouple

Claims (7)

A metal plate surface temperature measuring device for measuring the surface temperature of a metal plate in a straight path between rolls,
a first radiation measuring mechanism for measuring the radiance or temperature of a surface of the metal plate facing the roll of a wedge formed by the metal plate as a roll for changing the direction of the metal plate;
a second radiation measurement mechanism for measuring the radiance or temperature of the surface of the wedge opposite the roll of the metal plate;
an emissivity calculation mechanism for calculating emissivity from the radiance or temperature measured by the first radiation measurement mechanism and the radiance or temperature measured by the second radiation measurement mechanism;
a radiation temperature measuring mechanism that measures the temperature of the surface of the metal plate using the calculated emissivity;
A surface temperature measuring device for a metal plate. 2. The apparatus for measuring the surface temperature of a metal plate according to claim 1, wherein said first radiation measuring mechanism and said radiation temperature measuring mechanism are composed of one radiation thermometer having a long field of view in the longitudinal direction of said metal plate. The emissivity used for temperature measurement by the radiation temperature measuring mechanism is such that the surface position of the metal plate for which the emissivity is calculated is the same as the surface position of the metal plate for which temperature is measured by the radiation temperature measuring mechanism. The metal according to claim 1 or 2, which is determined based on the positional relationship between the second radiation measurement mechanism and the radiation temperature measurement mechanism and the conveying speed of the metal plate or the rotation speed of the roll so that Plate surface temperature measuring device. 4. The emissivity calculation mechanism according to any one of claims 1 to 3, wherein the emissivity is calculated as a ratio of the radiance measured by the second radiation measurement mechanism to the radiance measured by the first radiation measurement mechanism. 1. A surface temperature measuring device for a metal plate according to claim 1. at least one of the first radiation measurement mechanism and the second radiation measurement mechanism measures the temperature of the metal plate;
The emissivity calculation mechanism calculates the temperature of the metal plate measured by at least one of the first radiation measurement mechanism and the second radiation measurement mechanism from the relationship between the black body radiance and the temperature calculated in advance. calculating the blackbody radiance, and calculating the emissivity by using the blackbody radiance calculated according to the temperature as the radiance measured by at least one of the first radiation measurement mechanism and the second radiation measurement mechanism; The surface temperature measuring device for a metal plate according to claim 4. A metal plate annealing facility comprising the metal plate surface temperature measuring device according to any one of claims 1 to 5. A method for measuring the surface temperature of a metal plate, which measures the surface temperature of the metal plate in a straight path between rolls,
measuring the radiance or temperature of the surface of the metal plate on the roll side of the wedge formed by the roll that changes the direction of the metal plate and the metal plate;
measuring the radiance or temperature of the surface of the wedge opposite the roll of the metal plate;
Emissivity is calculated from the measured radiance or temperature of the surface on the roll side and the measured radiance or temperature of the surface opposite to the roll,
A method for measuring the surface temperature of a metal plate, wherein the temperature of the surface of the metal plate is measured using the calculated emissivity.

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