JP2010265533A - Heating controller and heating control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating controller capable of more correctly determining that a metallic material is suitably heated, thereby controlling a heating furnace. <P>SOLUTION: The heating controller 10 controls a heating furnace 1 where a metallic material F is heated while being carried to a furnace length direction. The heating controller 10 includes: a plurality of temperature measuring devices 100 arranged along the carrying direction and measuring the temperature distribution in the surface of the metallic material; a position decision part 11 deciding a first position P1 in which temperature is discriminated to be a high one compared with the other position and to be controlled during the heating stage in the surface of the metallic material and a second position P2 in which temperature is discriminated to be a lower one compared with the other position and to be controlled during the heating stage; a temperature difference calculation part 12 calculating the temperature difference between the first position and the second position based on the measured temperature distribution; and a discrimination part 22 discriminating the completion of the heating of the metallic material based on the temperature difference. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heating control apparatus and a heating control method for controlling a heating furnace that heats a metal material while conveying the metal material in the furnace length direction.

  A heating furnace is used for processing various metal materials. For example, various heating furnaces such as continuous slab heating furnaces are used only in the field of steel industry. Heating in a continuous billet heating furnace is used in subsequent steel rolling mills to ensure a temperature that creates the properties required for the product, such as material, surface quality, dimensional accuracy such as width and thickness, etc. To be done. Therefore, it is very important to heat the steel slab to an appropriate temperature in the heating furnace.

  For example, in the case of a continuous hot-rolling factory that manufactures hot-rolled steel strip, it is necessary to complete the finish rolling at the Ar3 transformation point or higher in order to secure the material on the finish rolling mill exit side, The upper limit temperature is set for the purpose of preventing the generation of scale wrinkles due to blisters. Moreover, since these temperature conditions change with the components of steel etc., the temperature of the steel materials in a heating furnace also changes with the components of steel, etc. Accordingly, the heating furnace is required to accurately heat the metal material to a desired temperature corresponding to the change of the heating target.

JP-A-8-246058 JP 58-113327 A JP 61-292528 A JP-A-62-22089 JP 2005-134153 A

  On the other hand, the needs for metal materials in recent years have been diversified and advanced, and it is also required for the heating furnace to produce various materials and types of metal materials by changing the heating temperature in a short cycle. For example, in the case of the above continuous billet furnace, in order to continuously roll various steel types in subsequent rolling mills, it is necessary to frequently change the furnace temperature, which is the controlling factor of the heating temperature, It is necessary to change the heating time according to the heating / rolling efficiency of the steel, and it has become difficult to heat the steel material at a constant furnace temperature and a constant furnace time. Accordingly, there is a situation in which heating is required under conditions where the furnace temperature is changing, and it has become difficult to ensure the heating accuracy of the metal material to a desired temperature.

  Currently, for example, the temperature in a heating furnace of a metal material that is a material to be heated, such as steel, is measured by a thermocouple disposed in the furnace (also referred to as “furnace temperature”), and the in-furnace of the steel material. Predicting from time is generally done. In many cases, the heating control apparatus controls the heating furnace so that the prediction result falls within the range of variations allowable in material and quality with respect to the target temperature.

  However, as described above, when the heating temperature is changed in a short cycle, the temperature of the refractory in the heating furnace also changes at the same time. For example, when high-temperature heating is performed after performing low-temperature heating, the amount of fuel introduced into the furnace increases in order to raise the furnace temperature. Then, the furnace combustion gas temperature (also referred to as “gas temperature”) rises. As a result, since the radiant heat transfer from the gas increases, the inner surface temperature of the furnace refractory also increases, and the temperature of the metal material to be heated also increases due to the radiant heat transfer from the gas and the refractory inner surface. The measurement part at the tip of the thermocouple that measures the furnace temperature can be regarded as a minute point existing in the furnace in terms of radiant heat transfer, and the furnace temperature measured by the thermocouple is It can be considered that the temperature is determined by the balance of radiant heat transfer among the combustion gas, furnace wall inner surface, metal material, etc. at the point. Such a minute point, that is, a thermocouple, has a small heat capacity, and therefore easily fluctuates depending on the temperature of the combustion gas, the furnace wall inner surface, the metal material, and the like.

  Therefore, by using the furnace temperature that is easily affected by the temperature of the surrounding objects, the temperature of the metal material in the heating furnace and the temperature increase amount thereof are predicted to control the heating furnace as described above. In such a case, there is a drawback that the predicted value by the model tends to fluctuate more than the actual temperature of the metal material. In particular, when many varieties are to be heated and the frequency of changing the heating temperature is high, the estimated amount of temperature increase by the model often differs greatly from the actual temperature of the metal material.

  In a side burner type heating furnace in which a burner is installed on the side wall of the furnace, the flame is formed in the furnace width direction (in the case of a continuous slab heating furnace, the longitudinal direction of the steel material). In general, the flame length tends to increase as the burner combustion load increases, and the flame temperature distribution changes accordingly. As a result, for example, the temperature distribution of the metal material in the furnace width direction (longitudinal direction of the steel material) also changes. In general, it is necessary to always know the temperature distribution of the flame in the furnace width direction and predict the temperature distribution in the furnace width direction of the metal material based on the result. It is also difficult. Furthermore, as described above, when the combustion amount changes frequently, it is even more difficult to grasp the temperature distribution change in the furnace width direction of the metal material.

  As described above, it is difficult to predict the temperature of a metal material as a material to be heated in a heating furnace in which the heating temperature changes frequently or a side burner type heating furnace. As a result, the metal material in a subsequent process such as rolling is difficult. Led to variations in temperature. Such a variation in the temperature of the metal material during extraction from the heating furnace results in a variation in product characteristics such as dimensions, shape, and material, which is an operational problem in the subsequent process.

  While accurate heating is difficult in this way, various control methods for heating furnaces such as Patent Documents 1 and 2 have been developed in order to further improve heating accuracy.

  The control method of Patent Document 1 is for a continuous heating furnace capable of independently controlling the furnace temperature of each heating zone. In this control method, the temperature of the steel material is measured at an intermediate position of the heating zone, and the actual heat pattern obtained by the measured value is compared with the planned heat pattern. And when a track record is less than a plan, the temperature difference, the heating zone of a comparison position, or the furnace temperature of the next heating zone is raised. As a result, in this control method, the heat pattern of the steel material can be brought close to the planned heat pattern and heated to the target temperature with high accuracy. In this control method, the steel material temperature is measured in the heating furnace without using the steel temperature prediction model, and the target temperature is controlled based on the result.

  On the other hand, the control method of Patent Document 2 detects the temperature of a heated material that passes through the inside of a heating furnace having a heating zone and a soaking zone in a single upper and lower stage, and immediately detects the temperature of the heating material based on this detected temperature. The material to be heated is heated to a set temperature by adjusting the conveyance speed. As a result, in this control method, the heating efficiency is improved and the loss of heat energy is reduced.

  However, as described above, in a heating furnace in which the heating temperature changes frequently or in a side burner type heating furnace, the accurate temperature of the metal material to be heated is controlled even by the control method of Patent Documents 1 and 2 above. It is difficult to measure, and as a result, even if the control device side determines that the target temperature or the like has been reached, heating of the metal material may not actually be completed. In particular, in Patent Documents 1 and 2 described above, it is not possible to include a variation in the furnace temperature in the furnace width direction due to a change in heating temperature or a side burner. For example, a place where the temperature in a metal material is measured can be appropriately heated. On the other hand, there are cases where phenomena such as so-called “burning shortage” and “sideburning” occur, such as not reaching the target temperature in other places.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to more accurately determine that the metal material has been appropriately heated and control the heating furnace. It is in.

In order to solve the above problems, according to one aspect of the present invention, there is provided a heating control device that controls a heating furnace that heats the metal material while conveying the metal material in the furnace length direction,
A plurality of temperature measuring devices that are arranged at a plurality of locations along the conveying direction of the metal material and measure the temperature distribution of the surface of the metal material passing therethrough, and
On the surface of the metal material, it is expected that the temperature is higher than that at other positions and should be managed during the heating process, and the temperature is expected to be lower than that at other positions and is managed during the heating process. A position determining unit for determining a second position to be performed;
A temperature difference calculating unit that calculates a temperature difference between the first position and the second position determined by the position determining unit based on the temperature distribution measured by each of the plurality of temperature measuring devices for each of the plurality of locations; ,
Based on the temperature difference calculated by the temperature difference calculation unit, a determination unit that determines completion of heating of the metal material,
A heating control device is provided.

  The determination unit may determine completion of heating of the metal material when the temperature difference calculated by the temperature difference calculation unit is equal to or less than a predetermined target temperature difference.

  In addition, the determination unit, when the temperature difference calculated by the temperature difference calculation unit once exceeds the target temperature difference in at least one of the plurality of locations, and is below the target temperature difference, You may determine completion of a heating of the said metal material.

Further, based on the temperature difference in at least two of the plurality of locations calculated by the temperature difference calculation unit, the first position and the second position in the metal material at the time of extraction from the heating furnace. A temperature difference prediction unit for predicting the temperature difference;
The determination unit may determine that the heating of the metal material is completed at the time of extraction when the temperature difference predicted by the temperature difference prediction unit is equal to or less than the target temperature difference.

  Further, a furnace temperature control unit for controlling the furnace temperature of the heating furnace downstream of the temperature measuring device disposed in the at least two locations based on the temperature difference predicted by the temperature difference prediction unit. You may have.

  Further, based on the temperature difference predicted by the temperature difference prediction unit, a local heating device disposed downstream of the temperature measurement device disposed in the at least two locations in the transport direction is used, with a part of the metal material being used. You may further have a local heating control part controlled to carry out local heating.

  Moreover, you may further have a conveyance speed control part which controls the conveyance speed of the said metal material based on the temperature difference estimated by the said temperature difference prediction part.

  Further, the position determining unit determines the highest temperature position and the lowest temperature position in the surface of the metal material based on the temperature distribution measured by the temperature measuring device at one place close to the charging side of the heating furnace. You may determine to the said 1st position and the said 2nd position, respectively.

  The position determination unit may determine a maximum temperature position and a minimum temperature position at which an area occupying the surface of the metal material is a predetermined threshold value or more as the first position and the second position, respectively.

The temperature measuring device is
A luminance measuring unit that measures at least the radiant energy distribution of the metal material by monochromatic luminance having a wavelength at which absorption and emission by the furnace gas do not occur;
A temperature known object for correcting stray light in the heating furnace, disposed in the vicinity of the luminance measuring unit within the measurement range of the luminance measuring unit,
A calculation unit that obtains a temperature distribution of the metal material by correcting stray light of the monochromatic luminance distribution of the metal material and the temperature known object measured by the luminance measurement unit;
You may have.

In addition, the calculation unit is
When obtaining the temperature of the metal material, based on the radiant energy of the temperature known object and the temperature of the temperature known object, a stray light calculation unit that calculates the amount of stray light,
A temperature calculation unit that calculates a temperature distribution of the metal material based on the stray light amount calculated by the stray light calculation unit and a radiant energy distribution of the metal material;
You may have.

The luminance measurement unit is an imaging device that captures a monochrome luminance distribution of radiant energy of the metal material and the temperature known object as an image of a predetermined number of pixels.
The temperature known object may be arranged at a position where an area occupying in an image captured by the imaging device is 25 pixels or more.

  In addition, the temperature known object may be arranged at a position where an area occupying in an image captured by the imaging device is 100 pixels or more.

  Further, the emissivity of the temperature known object may be within the range of 0.1 before and after the emissivity of the metal material.

In addition, the brightness measurement unit further measures the radiant energy of the furnace inner wall of the heating furnace,
A storage unit in which a difference in radiant energy between the furnace inner wall and the temperature known object is recorded;
Based on the difference in the radiant energy recorded in the storage unit, an emissivity changing unit that grasps whether or not the emissivity of the temperature known object changes with time,
You may have.

In addition, the emissivity changing unit calculates the emissivity after the change with time when the elapse rate of the emissivity of the temperature known object occurs,
The calculation unit may perform the stray light correction using the emissivity after the change with time.

Moreover, the said temperature known object may be arrange | positioned in the position which satisfy | fills at least any one among the following conditions (A), (B), and (C).
(A) A position where the stray light amount in the furnace is substantially the same as the position of the metal material, and a position separated from the furnace wall by a distance where the amount of stray light is substantially the same. (B) The angle of the metal material with respect to the measurement surface is Position where the angle does not change or more (C) Position where no flame is sandwiched between the above metal materials

In order to solve the above problem, according to another aspect of the present invention, there is provided a heating control method for controlling a heating furnace that heats the metal material while conveying the metal material in the furnace length direction,
A temperature measuring step of measuring a temperature distribution of the surface of the metal material passing by a plurality of temperature measuring devices respectively disposed at a plurality of locations along the conveying direction of the metal material;
On the surface of the metal material, it is expected that the temperature is higher than that at other positions and should be managed during the heating process, and the temperature is expected to be lower than that at other positions and is managed during the heating process. A position determining step for determining a second position to be performed;
A temperature difference calculating step for calculating the temperature difference between the first position and the second position determined in the position determining step based on the temperature distribution measured by each of the plurality of temperature measuring devices, for each of the plurality of locations;
A determination step of determining completion of heating of the metal material based on the temperature difference calculated in the temperature difference calculation step;
A heating control method is provided.

  As described above, according to the present invention, the heating furnace can be controlled by more accurately determining that the metal material has been appropriately heated.

It is explanatory drawing for demonstrating the structure of the heating control apparatus which concerns on 1st Embodiment of this invention, and a heating furnace. It is explanatory drawing for demonstrating the structure of the heating control apparatus and heating furnace which concern on the same embodiment. It is explanatory drawing for demonstrating the example of a position determination by the position determination part which concerns on the embodiment. It is explanatory drawing for demonstrating the example of a temperature difference calculation by the temperature difference calculation part which concerns on the same embodiment. It is explanatory drawing for demonstrating operation | movement of the heating control apparatus which concerns on the same embodiment. It is explanatory drawing for demonstrating the structure of the heating control apparatus and heating furnace which concern on 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the structure of the heating control apparatus and heating furnace which concern on the same embodiment. It is explanatory drawing for demonstrating the structure of the heating control apparatus and heating furnace which concern on the same embodiment. It is explanatory drawing for demonstrating the temperature difference prediction by the heating control apparatus which concerns on the same embodiment, and a mature heat determination example. It is explanatory drawing for demonstrating the 1st example of the heating control method by the heating control apparatus which concerns on the same embodiment. It is explanatory drawing for demonstrating the 2nd example of the heating control method by the heating control apparatus which concerns on the embodiment. It is explanatory drawing for demonstrating the 3rd example of the heating control method by the heating control apparatus which concerns on the same embodiment. It is explanatory drawing for demonstrating operation | movement of the heating control apparatus which concerns on the same embodiment. It is explanatory drawing explaining the characteristic 2 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the characteristic 3 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the characteristic 3 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the characteristic 4 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the condition 1 of the characteristic 5 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the condition 2 of the characteristic 5 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the characteristic 5 which the temperature measurement method used for each embodiment of this invention has. It is explanatory drawing explaining the Example of the temperature measurement method used for each embodiment of this invention. It is explanatory drawing explaining the Example of the temperature measurement method used for each embodiment of this invention. It is explanatory drawing for demonstrating the temperature measuring apparatus which concerns on related technology. It is explanatory drawing for demonstrating the temperature measuring apparatus which concerns on related technology.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the following description, first, the first embodiment and the second embodiment of the present invention will be described in the order of the configuration, the operation, and the effect, respectively, in order to facilitate understanding of each embodiment of the present invention. On the other hand, the heating control device according to each embodiment of the present invention includes a temperature measuring device capable of measuring the temperature distribution on the surface of the metal material that is the material to be heated. As this temperature measuring device, various devices can be used as long as they can measure the temperature distribution on the surface of the metal material. However, in each embodiment of the present invention, the effect is particularly enhanced. In addition, a temperature measuring device and a temperature measuring method capable of accurately measuring the temperature distribution on the surface of the metal material are used. By using this temperature measuring device and temperature measuring method, the effect of each embodiment can be remarkably enhanced. Therefore, after explaining the above contents, the temperature measuring device will be described in detail.

That is, the following will be described in the following order so that each embodiment of the present invention can be easily understood.
1. First embodiment2. Second Embodiment 3. Temperature measuring apparatus and temperature measuring method used in each embodiment

  In the following, for convenience of explanation, a “continuous billet heating furnace (hereinafter simply referred to as a heating furnace)” will be described as an example of the heating furnace. Then, “steel pieces (also referred to as steel materials)” will be described as an example of the metal material to be heated. However, the heating furnace controlled by the present invention is not limited to the above continuous billet heating furnace, and is not limited to the steel industry. That is, the metal material may be various metal materials that require heat treatment, and the heating furnace itself may be various materials that are usually used for heating the metal material. .

1. 1st Embodiment FIG. 1A and FIG. 1B are explanatory drawings for demonstrating the structure of the heating control apparatus and heating furnace which concern on 1st Embodiment of this invention. Here, FIG. 1B has shown sectional drawing which cut | disconnected the heating furnace 1 in FIG. 1A by the AA line. In addition, as shown to FIG. 1A, each structure of the heating furnace 1 does not necessarily exist on the same plane (for example, the burner 2 and the temperature measurement apparatus 100). However, in FIG. 1B, for convenience of explanation, each main component is shown on the same sectional view. As above-mentioned, below, the case where the heating control apparatus which concerns on each embodiment of this invention is applied to the continuous billet heating furnace is mentioned as an example, and is demonstrated. First, the heating furnace will be described.

1-1. Heating furnace As shown in FIG. 1A, the heating furnace 1 heats a steel piece F while conveying a steel piece F, which is an example of a metal material, in the furnace length direction (also referred to as an x-axis direction or a conveyance direction). . That is, the slab F shown in FIG. 1A has one side of the heating furnace 1 (charging side, x-axis negative) so that the furnace width direction (also referred to as y-axis direction) is the longitudinal direction as shown in FIG. 1B. It is also charged from the charging inlet IN provided in the furnace wall at the end. And the steel slab F is extracted from the extraction port OUT provided in the furnace wall of the other side (extraction side, also called x-axis positive direction side) end part of the heating furnace 1 with a conveying apparatus.

  In addition, although it does not specifically limit as a conveying apparatus, The example which used the walking beam is shown in the heating furnace 1 which concerns on this embodiment. As shown in FIG. 1A, the walking beam type conveying apparatus has a skid beam 3 having a length approximately equal to the furnace length direction supported by a plurality of skid posts 4, and a steel piece on the skid beam 3. F is placed. The combination of the skid beam 3 and the skid post 4 is also called a skid. As shown in FIG. 1B, a plurality of skids are arranged in the furnace width direction. On the other hand, this skid is classified into a fixed skid and a movable skid, and the fixed skid and the movable skid are alternately arranged as shown in FIG. 1B. The movable skid moves back and forth in the furnace length direction (x-axis direction) while moving up and down in the furnace height direction (also referred to as the z-axis direction). As a result, the steel slab F is transported forward while the movable skid moves forward from the state supported by the skid beam 3 of the movable skid. Thereafter, when the movable skid moves downward, the steel piece F is supported by the fixed skid. Then, after the movable skid moves forward, the movable skid moves backward and then rises to support the steel piece F again. By repeating the operation of the movable skid, the steel slab F is sequentially conveyed in the furnace length direction.

  On the other hand, a plurality of burners 2 are arranged in the heating furnace 1, and the burners 2 are cooked. Accordingly, the steel slab F is heated by the frame (flame) ejected from the burner 2 while being transported to the transport device, that is, in the furnace. In the heating furnace 1 shown in FIGS. 1A and 1B, in the furnace width direction, the steel slab F is positioned opposite to both furnace walls in the furnace width direction as shown in FIG. A “side burner” that forms the frame is used. However, the arrangement position of the burner 2 is not particularly limited, and may be a so-called “axial burner” that is arranged on the furnace ceiling or the hearth and forms a frame in the conveying direction. The type of the burner 2 is not particularly limited, and various burners such as a gas fuel burner, a liquid fuel burner, and a regenerative burner can be used.

  In the heating furnace 1, the heating state of the steel slab F is controlled mainly by adjusting the conveying speed of the steel slab F by the conveying device and the combustion amount of each burner 2 by a control device (not shown). The

The heating furnace 1 according to the first embodiment of the present invention has been described above.
Next, the configuration of the heating control apparatus 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

1-2. Configuration of Heating Control Device As shown in FIGS. 1A and 1B, the heating control device 10 includes a temperature measurement device 100, a storage unit 142, a position determination unit 11, a temperature difference calculation unit 12, and a temperature difference storage unit 13. And a determination unit 14.

  The temperature measuring device 100 is disposed at a plurality of locations along the conveying direction of the steel slab F, that is, along the furnace length direction. And the temperature measuring apparatus 100 measures the temperature distribution of the surface of the steel slab F which passes the arrange | positioned location.

  In FIG. 1A, the case where the temperature measuring device 100 is arrange | positioned at each of five places along a conveyance direction is illustrated. Here, in order to distinguish each temperature measuring device 100, the temperature measuring device 100 arrange | positioned at each location is also called temperature measuring device 100A-100E, respectively. And when it says the temperature measuring apparatus 100, arbitrary temperature measuring apparatuses 100A-100E shall be shown.

  The number of the temperature measuring devices 100 arranged is not particularly limited, but at least two are arranged. The arrangement position of the temperature measuring device 100 is not particularly limited as long as the temperature measuring device 100 is arranged along the transport direction, but it is preferable that at least one temperature measuring device 100A is arranged in the vicinity of the charging inlet IN. .

  The temperature measuring device 100 is preferably a temperature measuring device that performs radiation temperature measurement, for example. However, as described above, the temperature measuring device 100 is not particularly limited as long as the temperature distribution on the surface of the steel slab F can be measured. However, the temperature measuring device 100 used in the present embodiment, which will be described in detail later, can accurately measure the temperature distribution on the surface of the steel slab F. Therefore, it is desirable to use the temperature measuring apparatus 100 described later in detail. 1A and 1B show an example in which a temperature measuring device 100 described later in detail is used. Therefore, the temperature measuring apparatus 100 mainly performs radiation temperature measurement. Therefore, the imaging device 110 of the temperature measuring device 100, the temperature known object 120, and the like are arranged at a position where the radiation light from the steel piece F can be imaged.

  The temperature measuring device 100 is controlled by the heating control device 10 and measures the temperature distribution of the steel slab F at a predetermined timing. That is, when the steel slab F enters the temperature measurement region Ar, the temperature measuring apparatus 100 images the radiance of the steel slab F and images the surface temperature distribution. Therefore, it is desirable that the heating control device 10 itself always keeps track of which position the steel slab F is being conveyed. Moreover, the temperature measuring devices 100A to 100E are controlled so as to sequentially measure the temperature of at least the same steel slab F. That is, when the temperature measuring device 100 </ b> A images one steel slab F, the temperature measuring devices 100 </ b> B to 100 </ b> E have the steel slab F passing through each placement location (temperature measurement region Ar). Measure temperature. As a result, the temperature of one steel slab F is measured at all points by all or two or more temperature measuring devices 100. In addition, although the steel slab F used as this temperature measurement object may be all the steel slabs F conveyed and heated, the 1 or more steel slabs F selected by the heating control apparatus 10 may be sufficient. .

  The temperature measurement result is recorded in the storage unit 142 by each temperature measurement device 100. At this time, it is desirable that the temperature measurement results for one steel piece F are recorded together in the storage unit 142. That is, the temperature measurement results obtained by the temperature measuring devices 100A to 100E are associated with each other or are all associated with one steel piece F that is a temperature measurement object. As a result, a plurality of temperature measurement results for one steel slab F and a plurality of temperature measurement results for another steel slab F are distinguished from each other. In addition, since this heating control apparatus 10 can control the heating degree for every steel slab F, below, operation | movement, a process, etc. with respect to one steel slab F are demonstrated, and with respect to the other steel slab F A description of similar operations and processes will be omitted as appropriate.

  The position determination unit 11 determines a reference 2 position on the surface of the steel slab F to be temperature-measured. These two positions are referred to as “first position P1” and “second position P2”. Both positions will be described with reference to FIG. FIG. 2 is an explanatory diagram for describing a position determination unit of the heating control apparatus according to the present embodiment.

  In the first embodiment, the first position P1 and the second position P2 are expected to be relatively high or low in temperature distribution compared to other positions during the surface temperature distribution of the steel slab F, respectively. Represents the position to be managed. In addition, the position which becomes high temperature or low temperature said here does not need to become high temperature or low temperature rather than all the other positions, and means that it becomes high temperature or low temperature rather than desired temperature. In other words, for example, a position that is desired to be at a temperature similar to that of another reference position may be a position that is higher or lower than the reference position. Furthermore, it is not always necessary that the temperature is actually high or low, and it may be a position where the temperature is high or low as expected. The first position P1 and the second position P2 are also referred to as “high temperature management point” and “low temperature management point”, respectively. The high temperature control point and the low temperature control point are desirably processed by a process after heating such as a rolling process and the like so that a temperature difference between them does not exceed a certain temperature. For example, in the case where it is desired to heat the steel slab F uniformly, if a part of the steel slab F is too low or too hot, unevenness may occur in molding or material adjustment at that position, resulting in deterioration of product quality. is expected. In addition, when it is desired to provide a temperature difference such as an inclination in the temperature distribution after heating the steel slab F, it is difficult to maintain product quality unless the desired temperature difference is realized. In this sense, the high temperature control point and the low temperature control point are both higher or lower than a desired temperature, and therefore can be said to be positions where the temperature is relatively higher or lower than other positions. Therefore, the position determination unit 11 specifies the position 2 that needs to be managed because it is predicted that the temperature will be high or low. In addition, although this 1st position P1 and 2nd position P2 may be determined based on the operation performance etc., for example, you may obtain | require from actual measurement by 100 A of temperature measuring apparatuses. The first position P1 and the second position P2 will be described for each of these determination methods.

First, the determination method based on the operation performance etc. in the heating furnace 1 is demonstrated.
It is rare that the steel slab F that has been charged in the heating furnace 1 and has not been heated until now becomes a heating target. Therefore, in this case, the position determination unit 11 determines the first position P1 and the second position P2 based on the past operation results. The operation results include, for example, product quality results such as a state before heating, a state during heating, a state after heating, a state after subsequent processing, and the like for the steel piece F that has been heated in the past. For example, when there is a track record in which the quality of the steel slab F has deteriorated after heating or subsequent processes such as rolling, the steel slab F is compared with other positions at least before, during or after heating. Then, the position where the temperature is high or low is specified, and the high temperature position and the low temperature position are recorded in advance as the operation results. According to the heating control device 10 according to the present embodiment, the position is specified based on the temperature distribution measurement result because the temperature measurement device 100 can measure the temperature distribution of the steel slab F. be able to. And the position determination part 11 sets this high temperature position and low temperature position to the position which should manage temperature in order to keep quality favorable. Since the data about the high temperature position and the low temperature position are different for each steel type, size, etc. of the steel slab F, the position determination unit 11 previously stores the high temperature position and the low temperature position for each steel type, size, etc. Are stored in advance. This database may be included in the position determination unit 11 itself, or may be recorded in another storage device (for example, the storage unit 142). And the position determination part 11 acquires characteristic information like identification information, a steel grade, size, etc. about the steel piece F which is a heating control object from the higher-order control apparatus which controls the heating furnace 1, for example. After that, the position determination unit 11 identifies one steel slab F from the database based on the characteristic information, and sets each of the high temperature position and the low temperature position associated with the steel slab F as the first position P1 or the second position. The position is determined as P2.

Next, a determination method based on actual measurement by the temperature measurement apparatus 100A will be described.
The temperature measuring device 100A is disposed on the charging side of the heating furnace 1, that is, at a location near the charging inlet IN. Therefore, the temperature measuring device 100 </ b> A measures the surface temperature distribution of the steel slab F when charged in the heating furnace 1. On the other hand, although depending on the heating performance by the heating furnace 1, the highest temperature position and the lowest temperature position on the surface of the charged steel slab F are located at other positions even during heating by the heating furnace 1. In comparison, it is expected that the temperature is relatively high or low, or the temperature is higher or lower than the desired temperature, and as a result, the temperature is higher or lower than other reference positions. Therefore, the position determination unit 11 is based on the temperature distribution measured by the temperature measuring device 100A on the charging side, and on the surface of the steel slab F, the highest temperature position (position that is the highest temperature) and the lowest temperature position (at the lowest temperature). A certain position) is determined as a first position P1 and a second position P2, that is, a high temperature control point and a low temperature control point, respectively. The maximum temperature position and the minimum temperature position mean positions where the maximum temperature and the minimum temperature of the steel slab F are charged in the heating furnace 1, and other positions during or after heating. It is not necessary to have the highest temperature and the lowest temperature than all the positions. As described above, the maximum temperature position and the minimum temperature position are relatively higher or lower than the other positions, or higher or lower than the desired reference temperature. It means the position that is expected to be.

  However, when performing position determination based on this actual measurement, an abnormal temperature position is generated in the surface temperature distribution measured by the temperature measuring device 100A, which is not suitable for determination as a reference point because the temperature is locally high or low due to some abnormality. It is also possible to do. In this case, in order to prevent such an abnormal temperature position from being determined as the first position P1 or the second position P2, the position determination unit 11 is the most based on the surface temperature distribution measured by the temperature measurement device 100A. The area (or the number of pixels) of the position where the temperature is high or the position where the temperature is the lowest is extracted. If the area is less than the predetermined threshold, the position determination unit 11 confirms whether the area is also equal to or greater than the threshold for the next highest temperature position or the next lowest temperature position. To do. As a result, the position determination unit 11 can determine the position having the highest temperature or the position having the lowest temperature where the area is equal to or greater than the threshold as the first position P1 or the second position P2. The abnormal temperature position has a smaller area than the area of the surface of other ordinary steel slab F, and the area varies depending on the use of the heating furnace 1, the characteristics of the steel slab F, the heating state, and the like. Therefore, it is desirable to previously obtain a threshold value (for example, the maximum area) for the area of the abnormal temperature position based on actual measurement.

  In determining the first position P1 and the second position P2, it is possible to appropriately set whether the operation is based on the actual operation value or the actual measurement value. For example, when the operation results for the steel slab F are in the database, the first position P1 and the second position P2 are determined based on the operation results, and when they are not in the database, based on the actual measurement values. It is also possible to decide. Or, for example, only when the credibility that the first position P1 and the second position P2 are determined based on the operation results or the like is preferable for maintaining the product quality is obtained based on the past operation results or control results, etc. It is also possible to make decisions based on operational results. The same applies to the case of actual measurement values. However, when the first position P1 and the second position P2 are determined based on the actual measurement value, that is, the measurement result by the temperature measuring device 100A, it is not necessary to prepare a database in advance, and the actual maximum temperature position and minimum Since the temperature position is determined, it is possible to determine the position more easily and reliably.

An example of determining the first position P1 and the second position P2 is shown in FIG.
FIG. 2 is an explanatory diagram for explaining an example of position determination by the position determination unit according to the present embodiment. In the following, for convenience of explanation, an example is given in which the position determination unit 11 determines the first position P1 and the second position P2 shown in FIG. 2 as points to be managed by the determination method based on the operation results and the like. Will be described.

The temperature difference calculation unit 12 calculates a temperature difference between the first position P1 and the second position P2 determined by the position determination unit 11 based on the temperature distribution measured by each of the plurality of temperature measurement devices 100A to 100E. The calculation is performed for each location where each of the plurality of temperature measuring devices 100A to 100E is disposed. That is, for example, the temperature measurement device 100C will be described as an example. The temperature difference calculation unit 12 stores the temperature distribution that is the measurement result of the temperature measurement device 100C and information indicating the first position P1 and the second position P2. Acquired from the unit 142 and the position determination unit 11. Then, the temperature difference calculation unit 12 extracts a temperature T1 corresponding to the first position P1 and a temperature T2 corresponding to the second position P2 in the temperature distribution, and calculates the temperature difference ΔT by the following formula A. To do.
ΔT = T1-T2 (Formula A)

  The temperature difference calculation unit 12 calculates the temperature difference ΔT for each of the plurality of temperature measuring devices 100A to 100E. And the temperature difference calculation part 12 makes the temperature difference (DELTA) T into at least one of the temperature measurement apparatus 100A-100E in which the calculation was performed, and the position (installation location of the temperature measurement apparatus 100) in the conveyance direction, and the steel slab F. And recorded in the temperature difference storage unit 13.

  FIG. 3 shows an example of the calculation result of the temperature difference ΔT by the temperature difference calculation unit 12 for each position. FIG. 3 is an explanatory diagram for explaining a temperature difference calculation example by the temperature difference calculation unit according to the present embodiment. In FIG. 3, in order to associate the temperature difference ΔT with the temperature measurement device 100 with respect to the temperature difference ΔT, reference numerals 100 </ b> A to 100 </ b> E are attached to the positions of the temperature measurement devices 100 </ b> A to 100 </ b> E (positions in the x-axis direction). Moreover, the furnace length of the heating furnace 1 in which the measurement and the measurement result example were performed was about 40 m, and the position of the charging inlet IN on the charging side was set to 0 m. As shown in FIG. 3, it can be seen that the temperature difference ΔT gradually increases to the positions of the temperature measuring devices 100 </ b> A to 100 </ b> C and then decreases. In addition, transition of the temperature difference (DELTA) T shown in FIG. 3 has shown the example when the steel slab F is heated appropriately.

  The determination unit 14 acquires the temperature difference ΔT calculated by the temperature difference calculation unit 12 from the temperature difference storage unit 13, and determines the completion of heating of the steel slab F based on the temperature difference ΔT. The determination unit 14 according to the present embodiment determines completion of heating at the temperature difference ΔT, that is, completion of heating of the steel slab F when positioned in the temperature measurement region Ar of the temperature measurement device 100 corresponding to the temperature difference ΔT. To do. However, the determination unit 14 is not necessarily required to determine the completion of heating at the positions of all the temperature measurement devices 100A to 100E, and is at the time of extraction, that is, the temperature measurement region of the temperature measurement device 100E arranged at a position close to the extraction port OUT. It is desirable to determine the completion of heating of the steel slab F when positioned at Ar. Therefore, below, for convenience of explanation, a case will be described in which the completion of heating of the steel slab F when positioned in the temperature measuring region Ar of the temperature measuring device 100E is described.

At this time, various methods can be considered as the determination of the completion of heating.
For example, the determination unit 14 may determine the completion of heating of the steel slab F when the temperature difference ΔT is equal to or less than a predetermined target temperature difference (also referred to as an allowable limit temperature difference) Tc. As shown in FIG. 3, in this embodiment, 15 degreeC is set as this target temperature difference Tc. Therefore, the determination unit 14 determines that the heating of the steel slab F is completed when the temperature difference ΔT is 15 ° C. or less. For example, in the measurement example shown in FIG. 3, the temperature difference ΔT at the time of extraction, that is, the temperature difference ΔT corresponding to the temperature measuring device 100E is equal to or less than the target temperature difference Tc (15 ° C.). It is determined that the steel slab F has been heated during extraction. On the other hand, unlike FIG. 3, when the temperature difference ΔT corresponding to the temperature measuring device 100E exceeds the target temperature difference Tc (15 ° C.), the determination unit 14 has not completed the heating (whether the heating is insufficient). Overheating). The completion of heating is also referred to as “mature heat”, and the determination of completion of heating is also referred to as “mature heat determination”.

  As another example of the method for determining the completion of heating, as shown in FIG. 3, the determination unit 14 determines that the target temperature difference after the temperature difference ΔT once exceeds the target temperature difference at least at one or more locations. It is also possible to determine the heat of maturation of the steel slab F when: For example, the temperature difference ΔT may be expected to increase once during the heating process due to the characteristics of the heating furnace 1 and the properties of the steel slab F. In such a case, as described here, it is desirable to perform the mature heat determination based on the change state of the temperature difference ΔT.

  Further, in the above-described mature heat determination example, the case where the upper limit value of the temperature difference ΔT at the completion of heating is set as the target temperature difference Tc is described, but in addition to or instead of this upper limit value, It is also possible to provide a value. That is, when the temperature difference ΔT is equal to or greater than the target temperature difference that is the lower limit value, it may be determined that the steel slab F has matured. The use of the lower limit value as the target temperature difference in this way is particularly effective when, for example, it is desired to perform heating with a non-uniform temperature difference, such as gradient heating.

  Further, in the above-described determination example of the ripe heat, a case will be described in which the ripe heat determination of the steel slab F is performed at the time of extraction, that is, when positioned in the temperature measurement region Ar of the temperature measurement device 100E arranged at a position close to the extraction port OUT. However, the position where the determination of the mature heat is performed may be the position of the other temperature measuring devices 100A to 100D.

  The determination result by the determination unit 14 is preferably recorded in an external storage device or displayed on an external display device.

The configuration of the heating control apparatus 10 according to the first embodiment of the present invention has been described above.
Next, the operation of the heating control apparatus 10 according to the first embodiment of the present invention will be described with reference to FIG. Hereinafter, a case where the position determination unit 11 determines the first position P1 and the second position P2 based on actual measurement values will be described as an example. Changes in the case where the first position P1 and the second position P2 are determined based not on actual measurement values but on operation results or the like will be sequentially described.

1-3. Operation of Heating Control Device FIG. 4 is an explanatory diagram for explaining the operation of the heating control device according to the present embodiment.
As shown in FIG. 4, when the steel slab F to be controlled is charged into the heating furnace 1 from the charging inlet IN, first, step S01 is processed.

  In step S01 (an example of a temperature measurement step), the temperature measurement device 100A arranged in the vicinity of the charging inlet IN measures the temperature distribution of the steel slab F. The measured temperature distribution is sequentially recorded in the storage unit 142 as described above. Then, the process proceeds to step S03.

  In step S03 (an example of a position determination step), the position determination unit 11 acquires the measurement result by the temperature measurement device 100A recorded in the storage unit 142, and extracts the maximum temperature position and the minimum temperature position from the temperature distribution. These are determined as the first position P1 and the second position P2, respectively. Note that when the determination of the first position P1 and the second position P2 is performed based on the operation record or the like, step S01 can be omitted, and the temperature measurement by the temperature measuring device 100A is included in step S09 described later. It will be. Further, in this case, in step S03, the position determination unit 11 accesses the database representing the operation results and the like, specifies the high temperature position and the low temperature position corresponding to the steel slab F, and sets them as the first position P1. And the second position P2. After the process of step S03, the process proceeds to step S05.

  In step S05 (an example of a temperature difference calculation step), the temperature difference calculation unit 12 acquires a temperature distribution for which the temperature difference ΔT is to be calculated, and calculates the temperature difference ΔT between the first position P1 and the second position P2 in the temperature distribution. , Based on the above formula A. That is, in this step S05, a temperature difference ΔT is calculated for each of the temperature distributions measured in step S01 or step S09 described later (temperature distributions measured by any of the temperature measuring devices 100A to 100E). The calculated temperature difference ΔT is recorded in the temperature difference storage unit 13 for each steel slab F as described above. After the process of step S05, the process proceeds to step S07.

  In step S07, the heating control apparatus 10 checks whether or not there is a temperature measurement apparatus 100 that has not yet been subjected to temperature measurement. This confirmation can also be said to confirm whether or not there are temperature measuring devices 100A to 100E for which the temperature difference ΔT is not calculated. If such a temperature measuring device 100 exists, the process proceeds to step S09, and if not, the process proceeds to step S11. That is, in the case of this embodiment, since the steel slab F passes through the temperature measurement region Ar of the temperature measurement device 100E located closest to the extraction side, the temperature measurement device 100E finally measures the temperature. Therefore, in step S07, the process proceeds to step S09 until the measurement of the temperature measurement device 100E is performed, the measurement of the temperature measurement device 100E is performed, and the temperature difference ΔT of the measurement result is calculated. Proceed to S11. In this operation example, a case is described in which it is determined that the temperature has been matured when the temperature difference ΔT during extraction is equal to or less than the target temperature difference Tc, but it is assumed that the temperature difference ΔT is based on the temperature difference ΔT at another position. In step S07, it is confirmed whether or not the temperature measurement at that position is completed.

  In step S09 (an example of a temperature measurement step), the temperature measuring device 100 in which the steel slab F has reached the temperature measurement region Ar measures the temperature distribution of the steel slab F in the same manner as in step S01, and the temperature distribution is stored in the storage unit 142. Will be recorded. And the process after step S05 is repeated.

  On the other hand, in step S11 (an example of a determination step), whether the determination unit 14 has matured the steel slab F based on the temperature difference ΔT recorded in the temperature difference storage unit 13, that is, whether the heating has been completed. Determine whether or not. More specifically, the determination unit 14 compares the temperature difference ΔT of the temperature measurement device 100E disposed near the extraction port OUT with a preset target temperature difference Tc (for example, 15 ° C.). Then, if the temperature difference ΔT is equal to or less than the target temperature difference Tc, it is determined that the heat has matured, and if it exceeds the target temperature difference Tc, it is determined that the heat has not matured. The determination result is recorded on an external recording device or displayed on an external display device.

1-4. Effects and the like according to this embodiment The configuration and operation of the heating control apparatus 10 according to the first embodiment of the present invention have been described above. According to the heating control device 10, from the temperature distribution of the steel slab F in the temperature measurement region Ar of each of the temperature measuring devices 100A to 100E, the first position P1 that is the high temperature management point and the second position P2 that is the low temperature management point. Each temperature T1, T2 is detected, and the temperature difference ΔT is obtained. Based on the temperature difference ΔT and the target temperature difference Tc, it is possible to determine the mature heat of the steel slab F, that is, the completion of heating.

  The determination of the ripe heat based on the temperature difference ΔT between the first position P1 and the second position P2 as described above is based on the actual measurement values by the temperature measuring devices 100A to 100E. Compared with the determination of ripe heat based on the ambient temperature, the ripe heat of the steel slab F can be determined more accurately.

  Further, for example, it is conceivable that the temperature distribution on the surface of the steel slab F constantly changes, such as temporarily becoming locally high or low due to the characteristics of the heating furnace 1. However, the temperature inside the steel slab F does not always change following the surface temperature distribution, and it is very difficult to determine whether or not the inside is heated at a desired temperature. However, the heating control apparatus 10 according to the present embodiment is not merely based on the temperature distribution, but performs the determination of the ripe heat using the temperature difference ΔT between the two points serving as a reference, and thus a temporary change in the surface temperature. This makes it possible to make a more objective determination of ripeness that is not affected by

  Moreover, in the position determination part 11 which determines two points used as a reference | standard, the determination based on the operation performance etc. or the determination based on actual measurement is performed as mentioned above. Therefore, when based on actual measurements, there is a possibility that locally hot or cold places as described above may be determined as reference points, and in that case, it may be difficult to perform stable cram school heat determination. There is. However, when the position determining unit 11 according to the present embodiment determines the first position P1 or the second position P2 serving as a reference, the position of the highest temperature position or the lowest temperature position of which the area is equal to or greater than a predetermined threshold is determined. The first position P1 or the second position P2 can be determined. Therefore, it is possible to prevent a location where the temperature is locally high or low due to some abnormality from being determined as the reference point, and it is possible to further improve the accuracy of the determination of the ripe heat. In addition, as an example of such a cause of locally high temperature, a blister scale is used when the object to be heated is a steel piece F. The surface of the steel slab F is heated and heated to raise the temperature, and is covered with an oxide scale generated by the oxidation. The surface temperature of the steel slab F in the present embodiment usually indicates the temperature of the scale surface, but is not limited to the scale surface temperature. A part of this scale may swell locally due to a difference in thermal expansion from the ground iron, and may be lifted from the ground iron. This swollen state is called a blister. In the lifted state, the heat received by the scale from the surroundings becomes difficult to be taken away by the ground iron, and becomes higher in temperature than the scale surface in contact with the ground iron. Therefore, if the highest temperature position is simply determined as the first position P1, the blister scale may be selected as the reference point, which may reduce the accuracy of the determination of ripe heat. On the other hand, such a blister scale has a smaller area than other scale surfaces. Therefore, by excluding abnormal temperature positions such as this blister scale by a predetermined area (threshold value), it is possible to prevent the accuracy of the ripe heat determination from being lowered.

  In order to accurately determine the completion of heating in this way, it is very important that each of the temperature measuring devices 100A to 100E can measure an accurate surface temperature distribution. Therefore, it is desirable to use the temperature measuring device 100 using the principle of radiation temperature measurement, which will be described in detail later, as this temperature measuring device 100. When this temperature measuring device 100 is used, the accuracy of the determination of ripe heat is further improved. It is possible to make it.

  The heating control apparatus 10 according to the first embodiment has been described above. In addition, in this 1st Embodiment, the case where it was determined whether the heating with respect to the steel piece F was completed at the time of extraction was demonstrated. That is, in this 1st Embodiment, the steel slab F which has not completed heating will also be extracted from the heating furnace 1 in the state of insufficient heating. Therefore, as a second embodiment of the present invention, a second embodiment capable of preventing the steel piece F under-heated from being extracted from the heating furnace 1 will be described.

2. Second Embodiment A heating control device 20 according to a second embodiment of the present invention is based on the temperature difference ΔT calculated from the measurement results of the temperature measuring devices 100A to 100D, that is, the temperature difference ΔT during extraction, that is, temperature measurement. The temperature difference ΔT calculated from the measurement result of the device 100E is predicted in advance. And the heating control apparatus 20 controls the heating state by the heating furnace 1 grade | etc., Based on the prediction result. Various methods are conceivable as a method for controlling the heating state by the heating furnace 1 or the like, and at least one control method is adopted. Therefore, for convenience of explanation, a configuration capable of implementing a plurality of control method examples will be described below. However, any one of the examples described below or a combination thereof can be adopted as the control method. Hereinafter, the heating control apparatus 20 according to the second embodiment will be described in detail.

  However, the heating control apparatus 20 according to the second embodiment described below also has the same configuration as the heating control apparatus 10 according to the first embodiment. Therefore, the following description will focus on differences from the first embodiment of the heating control device 20.

2-1. Heating Furnace First, the heating furnace 1 will be described with reference to FIGS. 5A to 5C with respect to differences from the case shown in FIGS. 1A and 1B. FIG. 5A to FIG. 5C are explanatory diagrams for explaining the configuration of the heating control device and the heating furnace according to the second embodiment of the present invention. Here, FIG. 5B and FIG. 5C have shown sectional drawing which cut | disconnected the heating furnace 1 in FIG. 5A by the AA line and the BB line, respectively. As shown in FIG. 5A, the components of the heating furnace 1 do not necessarily exist on the same plane (for example, the burner 2 and the temperature measuring device 100). However, in FIG. 1B, for convenience of explanation, each main component is shown on the same sectional view.

  As shown in FIG. 5A, the heating furnace 1 further includes a partition wall 5 and a local heating device 6 in addition to the configuration shown in FIG. 1A.

  As shown in FIG. 5A, the partition wall 5 is formed to protrude from a plurality of locations on the furnace ceiling of the heating furnace 1, and divides the heating furnace 1 into a plurality of sections. Each section corresponds to the pre-tropical zone, the first heating zone, the second heating zone, and the soaking zone from the loading inlet IN side. Here, since the case where it divides into these sections is illustrated, three partition walls 5 are arranged in heating furnace 1.

  The number of the partition walls 5 is not particularly limited. For example, when the partition wall 5 is divided into three sections, ie, the pretropical zone, the heating zone, and the soaking zone, it may be two. Depending on the above, an appropriate number is appropriately arranged. Moreover, since the conveying apparatus of the heating furnace 1 which concerns on this embodiment is a walking beam type, although the partition wall 5 protrudes from a furnace ceiling, it protrudes from a hearth and a furnace wall as needed. Is also possible. Furthermore, the partition wall 5 is not always necessary and may not be arranged. However, in the case of the present embodiment, the heating furnace 1 is divided into a plurality of sections so that the prediction of the temperature difference ΔT during extraction, which is one of the features, and the subsequent heating control are easily understood. The case where temperature difference (DELTA) T of the piece F is measured is illustrated.

  That is, in the heating furnace 1 according to the present embodiment, at least one or more temperature measuring devices 100 of the heating control device 20 are arranged in each section (that is, each band). Although it is about the heating control apparatus 20, it will be as follows if the arrangement position of the temperature measuring apparatus 100 is demonstrated more concretely. That is, in the pretropical zone, one temperature measuring device 100A is arranged immediately after the inlet IN that is upstream, and one temperature measuring device 100B is further arranged immediately before the partition wall 5 that is downstream in the pretropical zone. Is done. And in each of the 1st heating zone and the 2nd heating zone, one temperature measuring device 100C and 100D are arranged near the middle position of each section. Finally, in the soaking zone, the temperature measuring device 100E is disposed downstream, that is, in the vicinity of the extraction port OUT. Thus, by arranging one or more temperature measuring devices in each section, it is possible to accurately grasp the heating status of each section. However, in the case of the present embodiment, if it is not necessary to determine whether the steel slab F is actually ripe based on the temperature difference ΔT immediately before extraction as in the first embodiment, the soaking zone temperature measuring device 100E. Is not necessarily required. However, based on the temperature difference ΔT immediately before extraction, whether the steel slab F is actually matured is determined as in the first embodiment, the quality is controlled, and the processing contents in the processing such as the subsequent rolling step It is very important to arrange the temperature measuring device 100E in the soaking zone in the sense that it is possible to change the temperature. Similarly to the first embodiment, when the position determination by the position determination unit 11 is determined based on the operation results or the like, the temperature measuring device 100A in the vicinity of the charging inlet IN is not necessarily required. However, it can be used in combination with a determination method based on actual measurement values and the like, and is very important for grasping the temperature change of the steel slab F in the heating furnace 1.

  The local heating device 6 is disposed on the soaking furnace roof, and is preferably disposed further downstream of the burner 2 which is the main side burner of the heating furnace 1. And the local heating apparatus 6 is comprised by the some burners 61-67 provided side by side in the furnace width direction, as shown to FIG. 5C, for example, and each burner 61-67 is cooked independently, and a flame | frame ( By generating Fl toward the steel slab F, a part of the steel slab F in the longitudinal direction (y-axis direction, furnace width direction) (part corresponding to the skid beam 3; see FIG. 5C) is locally localized. Can be heated. This local heating device 6 is controlled by a heating control device 20 (local heating control unit 233), as will be described later.

  In addition, in this embodiment, although the case where it comprises with the burners 61-67 as the local heating apparatus 6 is demonstrated, as the local heating apparatus 6, it is not limited to this example, The steel slab F is made into a longitudinal direction. Various heating devices that can be heated locally in the direction can be used. Further, the arrangement position of the local heating device 6 is not limited to the soaking hearth, but may be, for example, a soaking hearth, a furnace ceiling or a hearth in another section. However, this local heating device 6 is used as one heating control method for locally adjusting the temperature distribution when the predicted temperature difference ΔT, which is one of the features of the present embodiment, does not reach ripe heat. It is desirable to arrange downstream of two or more temperature measuring devices 100 where the difference ΔT is predicted. Moreover, although this local heating apparatus 6 is demonstrated as being provided in the heating furnace 1 in this embodiment, the heating control apparatus 20 may have.

The heating furnace 1 according to the second embodiment of the present invention has been described above.
Next, the configuration of the heating control device 20 according to the second embodiment of the present invention will be described with reference to FIGS. 5A to 5C.

2-2. Configuration of Heating Control Device As shown in FIGS. 5A to 5C, the heating control device 20 includes a temperature measurement device 100, a storage unit 142, a position determination unit 11, a temperature difference calculation unit 12, and a temperature difference storage unit 13. And a temperature difference prediction unit 21, a determination unit 22, an atmospheric temperature measurement device 200, and a furnace control unit 23. That is, the heating control device 20 includes a determination unit 22 instead of the determination unit 14 in the configuration of the heating control device 10 according to the first embodiment, and further includes a temperature difference prediction unit 21 and an ambient temperature measurement device. 200 and a furnace control unit 23. About the structure demonstrated in 1st Embodiment, since it is comprised similarly, detailed description is abbreviate | omitted and it demonstrates centering on a different point from 1st Embodiment.

  The temperature difference prediction unit 21 predicts a temperature difference ΔT between the first position P1 and the second position P2 of the steel slab F at the time of extraction. At this time, the temperature difference prediction unit 21 predicts the temperature difference ΔT during extraction based on two or more temperature differences ΔT calculated by the temperature difference calculation unit 12 from the temperature distribution measured by the temperature measuring devices 100A to 100E. To do. More specifically, the temperature difference predicting unit 21 extracts the temperature difference ΔT based on the two or more temperature measurement devices 100 from the extraction port OUT side and / or the temperature measurement device 100E in the vicinity of the extraction port OUT. It is desirable to predict the temperature difference ΔT at the time of extraction based on the temperature difference ΔT based on two or more temperature measuring devices 100 positioned on the OUT side. While the temperature difference prediction unit 21 predicts the temperature difference ΔT at the time of extraction, as shown in FIG. 3, the temperature difference ΔT is expected to temporarily increase and then decrease. Therefore, it is often possible to improve the prediction accuracy by predicting the temperature difference ΔT at the time of extraction based on the temperature difference ΔT after turning to decrease. Therefore, it is desirable to perform temperature difference prediction using the temperature difference ΔT based on two or more temperature measuring devices 100 from the extraction port OUT side. In addition, when the heating control is performed so that the steel slab F at the time of extraction is matured by the furnace control unit 23 described later, this heating adjustment is performed immediately before the extraction in order to suppress the influence on other steel slabs F. It is desirable to be performed in the soaking zone. Therefore, when performing such heating adjustment, it is desirable to predict the temperature difference ΔT during extraction even upstream of the soaking zone where this heating adjustment is performed.

  As a method for predicting the temperature difference ΔT during extraction by the temperature difference prediction unit 21, for example, a method by extrapolation (extrapolation) based on two or more temperature differences ΔT other than during extraction may be mentioned. Various methods such as linear approximation and nonlinear approximation can be used as the extrapolation method, but are not particularly limited, and thus detailed description thereof is omitted here. In addition, as another prediction method, a method based on the heating record can be cited. For example, for a steel slab F of the same or similar material and size, if there is a past record of heating at the same or similar conveying speed and combustion amount, the skid mark temperature ΔT measured during the heating and the steel being heated By comparing the skid mark temperature ΔT measured for the piece F, it is also possible to predict the skid mark temperature ΔT at the time of extraction.

  The determination unit 22 also determines the completion of heating of the steel slab F based on the same operation as the determination unit 14 according to the first embodiment, that is, based on the actual temperature difference ΔT calculated by the temperature difference calculation unit 12. Is possible. The detailed operation of this determination is the same as that of the determination unit 14. However, the determination unit 22 can perform not only a posteriori determination but also a prior determination. That is, the determination unit 22 further determines whether or not the heating of the steel slab F is expected to be completed at the time of extraction based on the temperature difference ΔT during extraction predicted by the temperature difference prediction unit 21. It is possible. As a determination method in the determination of the ripe heat, a method similar to that of the determination unit 14 can be used except that the temperature difference ΔT used for the determination is not based on actual measurement but is the predicted temperature difference ΔT. . Here, a case will be described as an example where it is determined that heating is complete, that is, when the predicted temperature difference ΔT during extraction is equal to or less than the target temperature difference Tc.

  A prediction of the temperature difference ΔT during extraction by the temperature difference prediction unit 21 and a determination example by the determination unit 22 based on the predicted temperature difference ΔT will be described with reference to FIG. FIG. 6 is an explanatory diagram for explaining an example of temperature difference prediction and mature heat determination by the heating control apparatus according to the present embodiment.

  In FIG. 6, based on the temperature difference ΔT by the temperature measuring device 100D in the second heating zone and the temperature difference ΔT by the soaking zone temperature measuring device 100E immediately before extraction, the temperature difference prediction unit 21 performs the extraction (extraction An example in which the temperature difference ΔT (white circle in FIG. 6) of the steel slab F at the time of arrival at the mouth OUT is predicted is shown. In the case of this example, the predicted temperature difference ΔT (◯) is calculated to be lower than the target temperature difference Tc (for example, 15 ° C.). Accordingly, in this case, the determination unit 22 determines that the steel piece F is matured during extraction. In this case, as compared with the case where the determination is made based on the temperature difference ΔT of the temperature measurement device 100E immediately before extraction, the amount of heating performed while the distance between the temperature measurement device 100E and the extraction port OUT is conveyed is also taken into consideration. Therefore, it is possible to more accurately determine the ripe heat of the steel piece F.

  On the other hand, FIGS. 7 to 9 show examples in which the predicted temperature difference ΔT does not satisfy the mature heat determination condition. 7-9 is explanatory drawing for demonstrating the 1st example-3rd example of the heating control method by the heating control apparatus which concerns on this embodiment, respectively.

  7 to 9 also show changes in the temperature difference ΔT (●) after the heating adjustment by the furnace control unit 23 described later. However, the temperature difference ΔT in the case where such adjustment is not performed is shown. The data points are shown as black squares (■).

  FIG. 7 shows a temperature difference ΔT by the temperature measuring device 100C in the first heating zone and a temperature difference ΔT by the temperature measuring device 100D in the second heating zone upstream of the soaking zone temperature measuring device 100E immediately before extraction. Based on this, an example is shown in which the temperature difference prediction unit 21 predicts the temperature difference ΔT (white square □ in FIG. 7) of the steel piece F at the time of extraction (when the extraction port OUT arrives). In this example, the predicted temperature difference ΔT (□) is calculated to be higher than the target temperature difference Tc (for example, 15 ° C.). Therefore, in this case, the determination unit 22 determines that the steel slab F is expected not to be fully heated during extraction. Therefore, the determination unit 22 instructs the furnace control unit 23 that the heating adjustment of the steel slab F is necessary, and the furnace control unit 23 indicates the temperature distribution immediately before the soaking season (measurement result by the temperature measuring device 100D). Will be output.

  In addition, the furnace control part 23 which received this output adjusts the heating state by the heating furnace 1, and the adjustment result is reflected also in the measurement result by the temperature measuring apparatus 100E. Therefore, the temperature difference prediction unit 21 predicts the temperature difference ΔT at the time of extraction again based on the temperature difference ΔT of the temperature measurement device 100E and other temperature differences ΔT, and the determination unit 22 indicates the prediction result. It is desirable to perform the same mature heat determination again based on the temperature difference ΔT.

  Based on the temperature difference ΔT predicted by the temperature difference prediction unit 21, the furnace control unit 23 adjusts the heating state of the heating furnace 1 in the soaking zone so that the determination result by the determination unit 22 indicates the completion of heating. At this time, the furnace control unit 23 may determine how to adjust the heating state based on the temperature distribution measured by the temperature measuring device 100D immediately before soaking. As the method for controlling the heating state, various methods can be used as described above. However, in the present embodiment, a case will be described in which at least one of “furnace temperature adjustment by the burner 2”, “local heating by the local heating device 6”, and “adjustment of the conveyance speed” is used as a control method. Which of the three heating adjustments is to be performed is preferably determined by the furnace control unit 23 based not only on the predicted temperature difference ΔT but also on the temperature distribution immediately before soaking, the energy efficiency, the heating deadline, and the like. . In order to perform each heating adjustment, the furnace control unit 23 includes a furnace temperature control unit 231, a conveyance speed control unit 232, and a local heating control unit 233 as shown in FIG. 5A. Each heating adjustment method and characteristic examples will be described in each configuration, and these configurations will be described below.

  The furnace temperature control unit 231 is transported more than the temperature measurement device 100 (for example, temperature measurement devices 100C and 100D) that measures the temperature distribution used for the prediction based on the temperature difference ΔT predicted by the temperature difference prediction unit 21. The furnace temperature of the heating furnace 1 (that is, soaking zone) downstream in the direction is controlled. Then, the furnace temperature control unit 231 determines how much the atmospheric temperature needs to be adjusted based on the predicted temperature difference ΔT and the atmospheric temperature in the furnace, and adjusts the atmospheric temperature by the determined amount. Therefore, the fuel flow rate of the soaking zone burner 2 is adjusted. At this time, the furnace temperature control unit 231 may also refer to the furnace atmosphere temperature measured by the atmosphere temperature measuring apparatus 200 arranged in each section of the heating furnace 1. The adjustment amount of the combustion flow rate is preferably determined in advance corresponding to the temperature difference ΔT and the temperature distribution based on the operation results, the adjustment results, the experimental results, and the like.

  In the first example of the heating control shown in FIG. 7, since the predicted extraction temperature difference ΔT exceeds the target temperature difference Tc, the furnace temperature control unit 231 determines the adjusted ambient temperature from the difference that exceeds, Adjustments are made to reduce the fuel flow rate so that the ambient temperature is reached. As a result, the furnace temperature (atmosphere temperature) when the heating adjustment is performed is lower in the soaking zone than when the heating adjustment is not performed. Then, the temperature difference ΔT (black circle (●)) when the furnace temperature adjustment is performed is reduced in the soaking zone compared to the case where the furnace temperature adjustment is not performed by the decrease, and the temperature difference prediction unit 21 The temperature difference ΔT predicted by (white circle (◯)) also decreases to the target temperature difference Tc or less. In the example shown in FIG. 7, the reason why the temperature difference ΔT in the actual steel slab F is reduced by the furnace temperature control unit 231 lowering the ambient temperature is that the effect of the ambient temperature is reduced by lowering the ambient temperature. This is because the temperature increase rate at the first position P1 that is likely to increase is lowered, and as a result, the difference between the temperature T2 at the second position P2 and the temperature T1 at the first position P1, which is less sensitive to the ambient temperature, is reduced. .

  When the heating adjustment by the furnace temperature control unit 231 is performed, the conveyance speed is not lowered as compared with other heating adjustments, so that not only the productivity is not lowered but also the local heating device 6 is not required to be arranged. Therefore, the heating furnace 1 or the heating control device 20 can be configured easily and at low cost. In addition, when the lower limit is provided as the target temperature difference Tc and the predicted temperature difference ΔT is lower than the lower limit, the furnace temperature control unit 231 controls the burner 2 so that the ambient temperature rises. .

  The conveyance speed control unit 232 controls the conveyance speed of the steel slab F by the conveyance device based on the temperature difference ΔT predicted by the temperature difference prediction unit 21. That is, the conveyance speed control unit 232 adjusts the in-furnace time in the soaking zone for each steel piece F. At this time, the conveyance speed control unit 232 may determine how much the conveyance speed is to be adjusted based on the predicted temperature difference ΔT, and further, the ambient temperature disposed in each section of the heating furnace 1. The furnace atmosphere temperature measured by the measuring apparatus 200 may also be referred to. It is desirable that the adjustment amount of the conveyance speed is determined in advance corresponding to the temperature difference ΔT and the temperature distribution based on the operation results, the adjustment results, the experimental results, and the like.

  In the second example of heating control shown in FIG. 8, since the predicted extraction temperature difference ΔT exceeds the target temperature difference Tc, the conveyance speed control unit 232 determines the adjusted conveyance speed from the difference that exceeds, The transfer device (movable skid or the like) is controlled so that the transfer speed (for example, 10% reduction) is achieved. As a result, the temperature difference ΔT (black circle (●)) in the case where the heating adjustment is performed is reduced in the soaking zone and is predicted by the temperature difference prediction unit 21 as compared with the case where the heating adjustment by the conveyance speed adjustment is not performed. Temperature difference ΔT (white circle (◯)) also decreases to the target temperature difference Tc or less. In the example shown in FIG. 8, the reason why the temperature difference ΔT is reduced by adjusting the conveyance speed is that the temperature T1 at the first position P1 has a small difference from the furnace temperature and is difficult to raise. Since the temperature T2 at the second position P2 has a large difference from the furnace temperature, the rate of temperature increase is fast. Therefore, the temperature T2 at the second position P2 and the temperature at the first position P1 can be increased by extending the soaking time in the soaking zone. This is because the difference from T1 has decreased.

  When the heating adjustment by the transport speed control unit 232 is performed, it is not necessary to increase the fuel flow rate of the burner as compared with other heating adjustments, so that an increase in energy consumption can be suppressed, and the local heating device 6 Therefore, the heating furnace 1 or the heating control device 20 can be configured easily and at low cost. Note that when a lower limit is provided as the target temperature difference Tc and the predicted temperature difference ΔT is less than the lower limit, the transport speed control unit 232 controls the transport device so that the transport speed increases. .

  The local heating control unit 233 is transported more than the temperature measurement device 100 (for example, the temperature measurement devices 100C and 100D) that measures the temperature distribution used for the prediction based on the temperature difference ΔT predicted by the temperature difference prediction unit 21. The local heating device 6 disposed downstream in the direction is controlled so as to locally heat a part of the steel slab F. At this time, the local heating control unit 233 may determine how much of which position is to be heated based on the predicted temperature difference ΔT, but further, the atmosphere arranged in each section of the heating furnace 1 The furnace atmosphere temperature measured by the temperature measuring device 200 may also be referred to. It is desirable that how much of which position is heated is determined in advance corresponding to the temperature difference ΔT and the temperature distribution based on operation results, adjustment results, experimental results, and the like.

  In the third example of the heating control shown in FIG. 9, since the predicted temperature difference ΔT during extraction exceeds the target temperature difference Tc, the local heating control unit 233 determines that the skid beam in the vicinity of the second position P2 is based on the difference. The position corresponding to 3 is locally heated. As a result, the temperature difference ΔT (black circle (●)) in the case where the heating adjustment is performed is reduced in the soaking zone compared with the case where the heating adjustment by the local heating is not performed, and is predicted by the temperature difference prediction unit 21. The temperature difference ΔT (white circle (◯)) also decreases to the target temperature difference Tc or less.

  When the heating adjustment by the local heating control unit 233 is performed, it is possible to locally heat only the target steel slab F as compared to other heating adjustments, and thus the influence on the other steel slab F is affected. Less. In addition, when the lower limit value is provided as the target temperature difference Tc and the predicted temperature difference ΔT is lower than the lower limit value, the local heating control unit 233 sets the position corresponding to the skid beam 3 in the vicinity of the first position P1 locally. Will be heated.

The configuration of the heating control device 20 according to the second embodiment of the present invention has been described above.
Next, operation | movement of the heating control apparatus 20 which concerns on 2nd Embodiment of this invention is demonstrated, referring FIG. In the following, detailed description of operations similar to those of the first embodiment shown in FIG. 4 is omitted.

2-3. Operation of Heating Control Device FIG. 10 is an explanatory diagram for explaining the operation of the heating control device according to the present embodiment.
As shown in FIG. 10, step S101 is processed instead of step S07 in FIG.

  In step S <b> 101, whether or not the temperature difference prediction unit 21 has recorded in the temperature difference storage unit 13 the number of data for which the temperature difference ΔT at the time of extraction can be predicted (that is, for example, the temperature difference ΔT of the temperature measuring devices 100 </ b> A to 100 </ b> D). To check. If the number of data necessary for temperature difference prediction is not complete, the process proceeds to step S09. If the necessary number of data is complete, the process proceeds to step S103.

  In step S103 (an example of a temperature difference prediction step), the temperature difference prediction unit 21 calculates a temperature difference ΔT during extraction based on two or more temperature differences ΔT recorded in the temperature difference storage unit 13. Then, the process proceeds to step S105.

  In step S105 (an example of a determination step), the determination unit 22 checks whether or not the heating of the steel slab F is predicted based on the temperature difference prediction result by the temperature difference prediction unit 21. When it is predicted that the heating has been completed, that is, when the steel slab F will be matured, the process proceeds to step S109. The determination result prediction may be recorded on an external recording device or displayed on an external display device.

  In step S107, the furnace control unit 23 adjusts the heating state in the soaking zone in the heating furnace 1. At this time, which of the three adjustment examples (combination or all of them) may be used is determined by the furnace control unit 23 based on the predicted temperature difference ΔT, energy efficiency, heating time limit, and the like. And also about the adjustment amount in the selected adjustment example, each of the furnace temperature control unit 231, the conveyance speed control unit 232 and the local heating control unit 233 of the furnace control unit 23 is determined based on the predicted temperature difference ΔT, etc. Heating adjustment is performed. After the process of step S107, the process proceeds to step S109.

  In step S109 (an example of a temperature measurement step), the soaking zone temperature measurement apparatus 100E immediately before extraction measures the temperature distribution of the steel slab F in the same manner as in steps S01 and S09, and records the temperature distribution in the storage unit 142. To do. Then, the process proceeds to step S111.

  In step S111 (an example of a temperature difference calculation step), the temperature difference calculation unit 12 calculates the temperature difference ΔT between the first position P1 and the second position P2 from the temperature distribution measured by the temperature measurement device 100E, as in step S05. , Based on the above formula A. Then, the process proceeds to step S113.

  In step S113 (an example of a temperature difference prediction step), the temperature difference prediction unit 21 is based on two or more temperature differences ΔT recorded in the temperature difference storage unit 13 including the one for the temperature measurement device 100E, as in step S103. Thus, the temperature difference ΔT during extraction is calculated. Then, the process proceeds to step S115.

  In step S115, the determination unit 22 determines whether or not the heating of the steel slab F is predicted to be completed based on the temperature difference prediction result by the temperature difference prediction unit 21 in step S113. The determination result is recorded on an external recording device or displayed on an external display device.

2-4. Effects and the like according to this embodiment The configuration and operation of the heating control device 20 according to the second embodiment of the present invention have been described above. According to this heating control device 20, of course, it is possible to achieve the effects and the like that can be achieved by the heating control device 10 according to the first embodiment. In addition, according to the heating control device 20, the temperature difference ΔT at the time of extraction is predicted from the temperature differences ΔT corresponding to the plurality of temperature measuring devices 100, and the aging of the steel slab F is determined based on the prediction result. It is possible to determine the degree of heat. Therefore, the determination accuracy can be further improved as compared with the determination of the mature heat in the first embodiment.

  In addition, this maturity determination is performed in advance before soaking, and if the determination result is predicted to be insufficient heating or overheating of the steel slab F, it is possible to perform heating adjustment by the furnace control unit 23. It is. As a result, it is possible to eliminate the expected underheating and overheating. Therefore, it is possible to greatly improve the heating accuracy of the steel slab F in the heating furnace 1.

  The heating control device 10 according to the first embodiment and the heating control device 20 according to the second embodiment may be configured by, for example, a general purpose or dedicated computer. And the heating control apparatus 10 or the heating control apparatus 20 can be comprised by making this computer run the program which implement | achieves the function of said each structure. The computer includes a CPU (Central Processing Unit), a recording device such as an HDD (Hard Disk Drive), a ROM (Read Only Memory), a RAM (Random Access Memory), and a LAN (Local Area Network). Communication devices connected to the computer, input devices such as a mouse / keyboard, magnetic disks such as flexible disks, optical disks such as various CDs (Compact Discs), MOs (Magneto Optical) disks, DVDs (Digital Versatile Discs), and semiconductors Drives that read and write to removable storage media such as memory, display devices such as monitors, speakers, headphones, etc. And an output device such as an audio output device. And this computer implement | achieves the function of each structure of the heating control apparatus 10 or the heating control apparatus 20 by running the program recorded on the recording device and the removable storage medium, or the program acquired via the network. Can do.

3. Next, a temperature measuring device and a temperature measuring method used in each embodiment of the present invention will be described. As described above, in each embodiment of the present invention, various temperature measuring devices and methods can be used as long as they measure the temperature distribution on the surface of the steel slab. The temperature measuring device and the temperature measuring method to be described can measure the temperature distribution very accurately as compared with other temperature measuring devices and temperature measuring methods. By accurately measuring the surface temperature distribution in this manner, the heating control device and method according to each embodiment of the present invention further enhances the above-described effects and more accurately determines the heat of maturation of the billet. It becomes possible. Therefore, in the following, the temperature measuring device and the temperature measuring method will be described in detail with reference to FIGS.

  In the following, it will be easier to understand how the temperature measurement device and the temperature measurement method can measure the temperature distribution more accurately than other temperature measurement devices and temperature measurement methods according to the related art. First, a related technique will be described, and then a temperature measurement method used in each embodiment of the present invention will be described. And after explaining the temperature measuring device for realizing this method, the example by the temperature measuring device and temperature measuring method used for each embodiment is explained. Furthermore, an example of the effect of the temperature measurement device and the temperature measurement method used in each of the embodiments will be described in comparison with Patent Documents 3 to 5.

That is, the following will be described in the following order so that each embodiment of the present invention can be easily understood. 3-1. Related technology 3-2. Outline of temperature measurement method used in each embodiment 3-3. Example of temperature measuring device used in each embodiment 3-4. Measurement example by temperature measuring device used in each embodiment 3-5. Examples of effects of temperature measuring devices used in each embodiment

3-1. Related Technology A related technology will be described with reference to FIGS. FIG.20 and FIG.21 is explanatory drawing for demonstrating the temperature measuring apparatus which concerns on related technology.

  When measuring the surface temperature of a steel slab in a heating furnace in a non-contact manner, a method of measuring thermal radiant energy from an object surface such as a radiation thermometer is generally used. However, in the heating furnace, there is radiant energy from the inner wall of the furnace or flame. This radiant energy is reflected by the surface of the steel slab and enters a sensor such as a radiation thermometer. Therefore, a radiation thermometer displays the temperature corresponding to the sum of the thermal radiant energy from the steel slab and the reflected energy reflected from the surface of the steel slab by the radiant energy from the inner wall or flame. Corresponding temperature errors occur. This reflected energy is called by various names such as stray light, reflected light, external light, back light, stray light noise, etc., all of which are the same, and is hereinafter referred to as “stray light”.

  For example, in measurement under outdoor air conditions or room temperature conditions, the radiant energy emitted from the atmosphere or indoor walls is smaller than the radiant energy of high-temperature steel slabs, so stray light errors do not become a problem. However, in a heating furnace having a high-temperature flame or a furnace wall, errors due to stray light are large, and therefore accurate temperature measurement is difficult.

  Therefore, a method for correcting the influence of stray light and obtaining a true object temperature has been developed. According to the method related to this related art, as shown in FIG. 20, first, a temperature known object 912 is placed in a heating furnace 911, and is calculated by the heat radiation theory from the known temperature of the object 912 by the calculation means 918. Based on the difference between the surface brightness and the measured value of the apparent brightness of the object 912, the amount of stray light in the heating furnace 911 is quantified. And further, the arithmetic means 918 subtracts the stray light amount in the heating furnace 911 from the apparent luminance of the steel slab 913 measured by the optical surface temperature measuring means 914 such as a radiation thermometer having a camera, and the true slab of the steel slab is obtained. Calculate the radiant energy to obtain the temperature. The temperature is displayed by the temperature display unit 919. As such a related technique, for example, Patent Document 5 is cited.

  In this method, an easily conceivable form is to place an object having a known temperature near the steel slab in order to reduce the stray light correction error.

However, such a form has the following problems.
Problem 1: When a steel slab moves, it is difficult to place an object with a known temperature in the vicinity thereof.
Problem 2: When an object having a known temperature is placed near the steel piece, that is, away from the camera, the number of pixels of the object having a known temperature in the image is reduced.

The problem 1 will be described.
When the billet moves, for example, in a walking beam type heating furnace or the like, there is a possibility that an object whose temperature is known is damaged by the movement of the billet. As a countermeasure, if a mechanism for moving the shielding plate according to the movement of the steel slab is provided, the measurement system itself becomes complicated, which is not practical.

The problem 2 will be described.
For example, in order to measure the temperature of a steel slab, the steel slab is arranged at a distant position, or to measure the temperature of a relatively small steel slab, it is necessary to use an imaging device having a certain degree of resolution so that the steel slab can be imaged. For example, when a 400,000-pixel camera is used as the imaging device, the viewing angle of one pixel is a small region having a width of 0.08 degrees and a height of about 0.08 degrees. If a temperature-known object is placed at a position away from the camera, the area of the temperature-known object that occupies the image becomes very small, so the output of one pixel is affected by spatial and temporal fluctuations, signal processing system disturbances, etc. It causes some variation.

  FIG. 21 shows an example of output variations in units of one pixel. As shown in FIG. 21, there is a large variation in output of one pixel unit, and this variation may cause a decrease in measurement accuracy. Therefore, in order to obtain high measurement accuracy, it is necessary to define an area instead of a single pixel and take the average value of the pixels in the area, and at least 5 × 5 pixels, preferably an average of 10 × 10 pixels or more Should be taken.

  However, considering a case where an object having a known temperature is arranged in the vicinity of a steel piece 6 meters away from the camera, for example, the width corresponding to a viewing angle of 0.08 degrees per pixel is about 10 millimeters. In order to take an average of 10 × 10 pixels, an area of 100 × 100 millimeters must be averaged.

  On the other hand, as the temperature known object 912, as shown in FIG. 20, it is practical to use a thermocouple thermometer 916 with a protective tube 917, which usually has a diameter of about 20 to 30 millimeters. As such, it is impractical to install a large temperature known object of 100 × 100 millimeters.

  As a result of earnest research on the conventional temperature measuring device and the temperature measuring device related to this related art, the present inventors have come up with the problems 1 and 2 as described above. In response to this problem, the inventors further installed the object having a known temperature, for example, a thermocouple with a protective tube, in the vicinity of the imaging piece, not in the vicinity of the steel piece, by the means described below, thereby further affecting the influence of stray light. Inventing a temperature measurement method that can be effectively corrected, and when used in the heating control device and method according to each of the above embodiments, it has also been found that the effect can be remarkably improved. Completed the invention.

3-2. Outline of Temperature Measuring Method Used in Each Embodiment Hereinafter, an outline of a temperature measuring apparatus according to each embodiment of the present invention will be described.
This temperature measuring method has the following features 1 to 3 broadly on the premise of the temperature measuring device according to the related art described above.

Feature 1: When a temperature-known object for correcting stray light is installed in the vicinity of the imaging device and the radiation energy of the steel slab is measured, a wavelength at which absorption and emission by the furnace gas do not occur is selected. The monochromatic luminance distribution is measured, and the obtained monochromatic luminance distribution is corrected for stray light to obtain the temperature.
Feature 2: The temperature-known object is arranged at a position where the size is at least 25 pixels, preferably 100 pixels or more, in terms of the number of pixels of the imaging device.
Characteristic 3: The material whose temperature is known uses a material whose emissivity is in the range of 0.1 before and after the emissivity of the steel piece.

  The temperature measuring device according to each embodiment will be described while sequentially explaining these features.

3-1-1. Feature 1
Feature 1: When a temperature-known object for correcting stray light is installed in the vicinity of the imaging device and the radiation energy of the steel slab is measured, a wavelength at which absorption and emission by the furnace gas do not occur is selected. The monochromatic luminance distribution is measured, and the obtained monochromatic luminance distribution is corrected for stray light to obtain the temperature.

  In this feature 1, “the wavelength at which absorption and emission by the furnace gas do not occur” does not mean that absorption and emission do not occur completely, but a wavelength at which absorption and emission are less likely to occur compared to other wavelengths. means. Further, “monochromatic luminance” and “single wavelength” mean that they are not all wavelengths, and include, for example, luminance of a wavelength having a predetermined width depending on wavelength selection accuracy. The temperature measurement process by the feature 1 and the temperature measuring device according to each embodiment will be described as follows.

  For example, when the temperature known object and the steel slab are close to each other, the stray light amount incident on both is almost equal, so the stray light amount obtained from the measurement result of the temperature known object is also irradiated to the steel slab. What is necessary is just to correct | amend the radiant energy of the measured steel piece. However, when the two are separated as in each embodiment, the equality of stray light amounts is not necessarily guaranteed.

  Therefore, in the temperature measuring device according to each embodiment, the following means are roughly used in order to ensure the equality of the stray light quantity between the temperature known object and the steel piece.

Means 1: Select a wavelength at which absorption and emission by the gas in the furnace do not occur, and measure a single wavelength.
Mean 2: The stray light correction calculation formula is created by strictly applying the theory of radiant heat transfer in order to enable theoretical evaluation of errors due to temperature distribution in the furnace.

(Means 1)
Each means will be specifically described below.
Carbon dioxide, water vapor, and the like generated by the combustion of fuel exist in the combustion furnace, and these gas bodies absorb radiant energy in the furnace and radiate energy corresponding to their own temperature. Since the gas temperature varies depending on the position in the furnace, the amount of stray light in the furnace varies depending on the position. However, the absorption and emission of gases such as carbon dioxide and water vapor are limited to some specific wavelength ranges in the spectrum. Therefore, stray light correction that does not include the influence of the gas in the furnace is possible by measuring the wavelength that avoids both the absorption / radiation wavelength region of carbon dioxide and the absorption / radiation wavelength region of water vapor.

  Therefore, in each embodiment, by measuring a wavelength satisfying the above conditions, for example, a single wavelength of 1 μm, it is possible to correct stray light under a condition in which the position of the temperature known object and the steel piece are separated. In addition, as in each embodiment, there is no precedent for an example in which the single wavelength condition is essential for the purpose of stray light correction.

(Means 2)
The calculation for correcting stray light in accordance with the use of a single wavelength uses the Plank equation for calculating radiant energy of a single wavelength, not the Stefan-Bolzmann equation used in general radiant heat transfer calculation. Specifically, the calculation is performed according to the following procedures 1 to 7.

  Procedure 1: In advance, an off-line blackbody standard furnace is used to create a relational expression between the output of the imaging device and the blackbody luminance.

  First, the temperature of the blackbody standard furnace is maintained at T [K]. The black body luminance E at the temperature T is calculated according to Planck's law (the following formula 1).

…（式１）

... (Formula 1)

Here, each constant of the above-mentioned formula 1 is as follows.
E: Black body luminance of wavelength λ [W / m ³ ]
λ: wavelength [m]
T: Temperature [K]
C1: Constant 3.74 × 10 ⁻¹⁶ [W / m ² ]
C2: Constant 0.014387 [μm · K]

  Next, the standard temperature point of the blackbody standard furnace is measured by the imaging device, and the output L of the imaging device is obtained. The same measurement is sequentially performed by changing the temperature T, and a relational expression between E and L is created by the least square method or the like. Here, the relational expression between E and L is represented by the following expression 2.

…（式２）

... (Formula 2)

  The relational expression expressed by Expression 2 means a characteristic expression specific to each imaging apparatus, and therefore needs to be created for each imaging apparatus when a new imaging apparatus is introduced. However, since this is a characteristic unique to the imaging apparatus, once this procedure 1 is performed, it is not necessary to perform it again thereafter. In each embodiment, for example, a wavelength of 1 μm is used as the measurement wavelength λ, and an optical filter can be used for selecting the wavelength. However, the measurement wavelength λ may be other wavelengths, and the wavelength selection method may be, for example, using an imaging element that captures only a specific wavelength in addition to the optical filter, or a specific wavelength included in the imaging device Needless to say, various methods can be used, such as extraction by image analysis.

Procedure 2: In an actual furnace, black body luminance E ₁ is calculated from Planck's law from the temperature T ₁ [K] of an object with a known temperature, for example, a thermocouple with a protective tube, as shown in Equation 3 below.

…（式３）

... (Formula 3)

Step 3: The image pickup device measures the temperature known object, obtaining an output L _1. The luminance corresponding to the output L ₁ is calculated by the above characteristic formula (formula 2) created off-line.

The luminance calculated in this procedure 3 is an apparent luminance including reflection of stray light, and corresponds to a quantity called emissivity in the field of radiant heat transfer. This is represented as _{G 1.} That is, the luminance _{G 1} is represented by the following formula 4.

…（式４）

... (Formula 4)

Procedure 4: The stray light amount J is calculated from E ₁ and G _{1 according} to the following formula 5.

…（式５）

... (Formula 5)

In Equation 5, ε ₁ is the emissivity of an object with a known temperature.
Here, the derivation process of Equation 5 will be described. The monochromatic radiation amount A radiated from the object surface at the temperature T is obtained by multiplying the black body luminance E calculated from Planck's law by the emissivity ε of the object surface. That is, the monochromatic radiation amount A is expressed by the following formula 6.

…（式６）

... (Formula 6)

  Further, the amount B of the in-furnace stray light (external irradiation) J reflected from the object surface is expressed by the following formula 7 from the radiation heat transfer theory.

…（式７）

... (Formula 7)

  Since the “apparent luminance” G measured by the imaging apparatus is the sum of the above A and B, it is expressed by the following formula 8.

…（式８）

... (Formula 8)

By transforming this equation, Equation 9 for calculating the stray light amount J is obtained. Therefore, by substituting _E 1, _{G 1} and epsilon ₁ in this equation 9, the equation 5 is derived.

…（式９）

... (Formula 9)

Step 5: The image pickup device measures the billet to obtain an output L _2. Then, the above characteristic equation (Equation 2), to calculate the luminance corresponding to the output L _2. This is the apparent luminance including reflection of stray light. This is represented as _{G 2.} That is, the luminance _{G 2} is expressed by the following equation 10.

…（式１０）

... (Formula 10)

The output L ₂ as measured by the imaging device here is expressed as a distribution to the surface of the steel strip. In other words, the output L ₂ for a predetermined location in the captured image of the imaging device reaches the predetermined location of the steel piece captured in the captured image, and the output L ₂ has a different value for each position in the captured image. Possible. Therefore, the luminance G ₂ calculated from the output L _{2 is} also distributed with respect to the steel slab. Incidentally, for convenience of explanation, the luminance G ₂ is, be described as the average luminance of the luminance or more points of one point in the luminance distribution. However, the subsequent calculation or the like for the luminance G _2, by performing each position corresponding to the steel strip in the captured image, in this temperature measuring method, it is needless to say that can measure the temperature distribution.

Procedure 6: Calculate the black body luminance E ₂ of the steel piece from the G ₂ and the stray light amount J (Equation 5) calculated in the procedure 4 by the following equation 11.

…（式１１）

... (Formula 11)

epsilon ₂ is the emissivity of the steel strip.
Here, the derivation process of this equation will be described.
Using the following equation 12 (the above equation 8) derived in the above step 4 and modifying this equation to obtain the black body luminance E, the above equation 11 is obtained.

…（式１２）

... (Formula 12)

Procedure 7: From this E ₂ , the temperature T ₂ [K] of the steel slab is obtained using the inverse function (equation 13) of the following Planck's law.

…（式１３）

... (Formula 13)

Here, Log is a natural logarithm.
By using the stray light correction method (procedure 1 to procedure 7) described here, the temperature of the steel slab can be obtained even when the temperature known object and the steel slab are separated. The reason will be described below.

  The radiant energy from the object of known temperature and the steel slab is the sum of the amount of radiation from the object itself and the amount of reflection of stray light received from the inside of the furnace. And each of steel slab is represented by the following formula 14 and formula 15.

…（式１４）

…（式１５）

... (Formula 14)

... (Formula 15)

  Here, the subscript 1 represents a temperature known object, and the subscript 2 represents a steel piece. The first term on the right side of each equation is the amount of radiation from the object itself, and the second term is the amount of reflection of stray light from the furnace on the object surface.

In the related art, correction is performed by adding / subtracting the difference ΔG (= G ₂ −G ₁ ) of the radiant energy, and the relationship between the apparent luminance G and the black body luminance E in the two formulas 14 and 15 above. Is obtained to obtain the brightness E and obtain the temperature of the steel slab. Therefore, in the method of the related art, it is necessary that ε ₁ and ε _{2 in} the above two expressions are equal, and (1-ε ₁ ) J ₁ and (1-ε ₂ ) J ₂ are equal. That is, since it is a requirement that the emissivity of the object of known temperature and the steel slab is equal, and the total of the stray light amounts J over the measurement wavelength band is the same, it is necessary to place both in the vicinity where the stray light is clearly equal. is necessary. On the other hand, in the temperature measurement method of each embodiment, as shown in the description of the correction calculation procedure, the equality of both types is not a requirement. That is, since a single wavelength with a small difference in stray light amount is used in the furnace, the second term (1-ε ₁ ) J ₁ and (1-ε ₂ ) J _{2 in} the above equation do not need to be equal, and the emissivity Even if ε and stray light J differ depending on the position, the measurement error can be reduced.

In general, the material heated in the heating furnace has a high emissivity because the surface is oxidized in the case of a metal material, and the emissivity of the material itself is high in the case of a nonmetallic material. Usually, the emissivity of the object to be heated is a value exceeding 0.8. Therefore, (1-ε) is smaller than ε, and the second term (1-ε) J is smaller than the first term εE in the above equation. Therefore, even if there is little difference in the stray J ₂ of the stray light J ₁ and steel strip position of the temperature known object position, the difference in the second term relatively value is small is only generated, the expression of the calculation result The impact of is small. In each embodiment, the measurement wavelength λ is set to a wavelength with little absorption / radiation by the furnace gas. Therefore, it is possible to very small difference between the stray J ₂ of the stray light J ₁ and steel strip position of the temperature known object position. Therefore, in each embodiment, it is possible to calculate as J ₁ = J ₂ without arranging the temperature known object and the steel piece close to each other. Even if the difference between J ₁ and J ₂ is different by about 10%, there is no significant effect on the error. This is because if the emissivity is about 0.8 and the difference in J is about 0.2, the difference on the right side of the above equation is only about (1−0.8) × 10% = 2%. It is.

  For the above reasons, if the temperature measurement method of each embodiment that performs single wavelength measurement is used, temperature measurement can be performed without greatly reducing accuracy even if a temperature known object is placed at a position where there is a slight difference in stray light. is there. That is, it is not necessary to place an object with a known temperature in the vicinity of the steel slab.

3-1-2. Feature 2
Feature 2. The temperature-known object is arranged at a position where the size is at least 25 pixels, preferably 100 pixels or more, in terms of the number of pixels of the imaging device.

The feature 2 will be described as follows.
As shown in Problem 2 above, in the related technology, since the area occupied by one pixel of the imaging device is small, the output of one pixel is affected by, for example, spatial and temporal fluctuations, disturbance of the signal processing system, etc. This causes variation. FIG. 11 shows the actual measurement value of the output of one pixel unit of the temperature known object.

  When the standard deviation of the actually measured values shown in FIG. 11 was calculated, σ = 11 ° C. Therefore, it is clear that if the stray light correction is performed using the measurement value of only one pixel, the error is large and it is not practical. Therefore, in the temperature measurement method of each embodiment, such a problem can be solved by taking an average value of a plurality of pixels and performing correction calculation using the average value.

Hereinafter, specific conditions will be described based on the considerations of the inventors who have derived this feature 2.
As described above, the standard deviation of one pixel unit was 11 ° C. According to the law of statistics, the standard deviation when taking n average values is inversely proportional to the square root of the number, so if the average of 25 pixels is taken, the standard deviation is about 1/5 of about 2 ° C. It becomes. If the average value of 100 pixels is taken, it is inversely proportional to the square root 10 of 100, so it is about 1/10 of 1/10.

  In the temperature measurement in the furnace, a standard deviation of 2 ° C. is almost practical, and 1 ° C. is sufficient. Therefore, it is necessary to place a temperature known object at a position where the number of pixels of at least 25 pixels (for example, 5 × 5 pixels), preferably 100 pixels (for example, 10 × 10 pixels) or more can be obtained.

  For example, it is appropriate to use a thermocouple with a protective tube as a known temperature object. Since the outer diameter of the thermocouple with a protective tube used in the heating furnace is about 20 to 30 mm, the measurement range is about 10 mm in the vertical and horizontal directions and about 10 mm in the circular shape.

  On the other hand, for example, in a commonly used CCD camera having about 400,000 pixels, the viewing angle of one pixel is about 0.08 degrees × 0.08 degrees. Therefore, the viewing angle when viewing 5 × 5 = 25 pixels is 0.4 ° × 0.4 °. Since tan 0.4 degree = 0.070, in order to capture a range of 10 mm × 10 mm at a viewing angle of 0.4 degree × 0.4 degree, it should be placed closer to the camera than 10 mm / 0.0070 = 1400 mm. I must.

  Although the calculation is performed for the case where the measured portion of the temperature-known object is 10 mm, if the same calculation is performed when the size is different, the position where the temperature-known object is to be placed is the size Y of the measured portion. On the other hand, it is desirable that the distance X from the imaging device satisfies the following expression 16.

…（式１６）

... (Formula 16)

  Based on such considerations, the present inventors have derived Feature 2 described above. Therefore, in each embodiment, the temperature-known object has a position where the size is at least 25 pixels (for example, 5 × 5 pixels), preferably 100 pixels (for example, 10 × 10 pixels) or more in the number of pixels of the imaging device. Placed in. In other words, for a temperature known object, if the size of the measured part of the temperature known object is Y and the distance from the imaging device is X, X is set to satisfy Equation 16 above. More specifically, X is set to a value smaller than 1400 mm when a CCD camera having about 400,000 pixels is used as the imaging device and Y is 10 mm. As a result, in the temperature measurement device according to each embodiment, the measurement error of the imaging device can be reduced and the temperature measurement accuracy can be improved.

3-1-3. Feature 3
Feature 3. The object whose temperature is known uses a material whose emissivity is in the range of 0.1 to the emissivity of the steel piece.

The feature 3 will be described as follows.
The inventors of the present invention theoretically examined the measurement results when the measurement conditions were variously changed, that is, the error in the temperature after stray light correction, with respect to the temperature measurement method of each embodiment.

  The examination conditions were as follows: in a combustion furnace having a length of 12 m and a height of 2.5 m, the furnace inner wall temperature was 1200 ° C., the temperature of the steel piece placed on the hearth was 900 ° C., and the emissivity of the steel piece was 0.86. The theoretical value of the amount of radiant heat transfer and the amount of reflected stray light on each surface under the conditions satisfying the above characteristics 1 and 2 was obtained. The calculation method is described by Yoshio Kato, “Introduction to Heat Transfer” (Yokendo) p. 377-p. The procedure shown in 382 was used.

  By applying the stray light correction calculation method described in the above feature 1 to the calculation result, the position of the temperature known object is set to the left wall position in the furnace in the furnace width direction as the origin 0 m point, and from the 0 m point to the right 12 m point The stray light correction value when changed every 2 m was calculated. The position of the imaging device was the left 0 m point, and the position of the steel slab was the center in the furnace width direction, that is, the 6 m point. The calculation results are shown in FIG. The emissivity ε shown in FIG. 12 is the emissivity of an object whose temperature is known, and the emissivity of the steel slab is fixed at 0.86.

  As shown in FIG. 12, according to this calculation result, for example, when the emissivity of a known temperature object is equal to the emissivity 0.86 of a steel slab, no matter where the known temperature object is, The temperature falls within a difference of 3 ° C. or less with respect to the true temperature of the billet 900 ° C.

  However, when there is a difference in the emissivity ε between the billet and the temperature known object, it can be seen that the temperature difference becomes large. When the emissivity of an object having a known temperature is in the range of 0.81 to 0.91, that is, about 0.05 to around 0.05 with respect to the emissivity ε = 0.86 of the billet, it is ± 6 ° C with respect to the true temperature of 900 ° C However, the emissivity of an object having a known temperature is about ± 13 ° C. in the range of 0.76 to 0.96, that is, in the range of about 0.1.

  If an error up to about 10 ° C is allowed in consideration of practicality, the emissivity of an object with a known temperature varies slightly depending on the temperature and emissivity level, but the material is within about 0.1 before and after the slab emissivity. The measurement error can be further reduced if it is preferably within about 0.05.

  On the other hand, in the related technology, a method of correcting stray light based on the luminance of an object whose temperature is known is adopted. In this related technology, the positional relationship between the steel slab and the temperature known object is not clearly shown, but in FIG. 1 illustrated as an example, the temperature known object is placed in the vicinity of the steel slab. It is thought that it is assumed to be placed in the vicinity.

  According to the knowledge of the inventors, as described above, when there is a large difference between the temperature of the steel slab and the furnace inner wall, for example, the temperature of the steel slab is 900 ° C. and the temperature of the furnace inner wall is 1200 ° C., the furnace Near the wall, it is strongly affected by stray light from the furnace wall. However, when the emissivity of an object with a known temperature and the emissivity of a steel slab are approximately the same, the effect is reduced. This is shown in FIG. FIG. 13 shows the calculation result when the emissivity ε of the known temperature object in FIG. 12 is 0.86, which is equal to that of the steel slab, and the calculation result when the emissivity ε is 0.76 away from the value. . That is, in FIG. 13, the ● plot is an example in the case where the emissivity of the steel slab and the known temperature object are approximately the same, and the x plot is an example in which the emissivity of the known temperature object is different from that of the steel slab. is there. Again, the steel slab was placed in the center of the furnace, i.e. 6 m.

  As shown in FIG. 13, when the emissivity is different, not only the temperature error increases, but also the difference between the vicinity of the furnace wall and the center increases. For this reason, in the related art, the emissivity is not stipulated. Therefore, although it is not clearly shown, it is considered that, as an embodiment, a temperature known object has to be placed in the vicinity of the steel piece.

  However, in each embodiment, by limiting the emissivity of the temperature known object, as shown in the ● plot of FIG. 13, even if the temperature known object is placed at a position away from the steel piece at the point of 6 m, the error is small. Measurement is possible.

  The features 1 to 3 included in the temperature measurement device according to each embodiment of the present invention have been described above. In addition to the features 1 to 3 described above, the temperature measuring device according to each embodiment further has the following features 4 and 5 in order to maintain and improve the measurement accuracy.

Feature 4: Dealing with time-dependent changes in emissivity Feature 5: Position of an object with a known temperature defined by the stray light quantity distribution in the furnace

  Next, features 4 and 5 will be described.

3-1-4. Feature 4
Feature 4: Dealing with changes in emissivity over time

The feature 4 will be described as follows.
When a thermocouple with a metal protective tube is used as a known temperature object, the emissivity of the known temperature object may change slightly due to the effect of oxidation due to long-term use or the like. Further, when a thermocouple with a ceramic protective tube is used, there is no fear of oxidation, but the possibility of emissivity change due to adhesion of soot and furnace dust cannot be excluded. Therefore, in the temperature measuring device according to each embodiment, such a change with time of the emissivity of the known temperature object can be dealt with by the following means.

Means 1: Method for grasping change in emissivity with time In general, in order to measure the emissivity on the surface of an object, it is necessary to measure the temperature and luminance of the object under conditions without stray light. Therefore, it is difficult to grasp the emissivity if it is installed in the furnace. However, if the operating conditions of the furnace are constant, the stray light quantity distribution in the furnace does not change, and the relationship between the radiance from an object with a known temperature and the radiance from the inner wall of the furnace is considered to be constant. Using this phenomenon, the difference between the furnace inner wall brightness in the field of view of the imaging device and the temperature known object brightness is recorded over a long period of time, and the presence or absence of emissivity changes with time is grasped by managing the trend under the same temperature conditions. Can be managed. For example, it can be determined that the emissivity of the temperature known object has changed when the change in the difference between the furnace inner wall brightness and the temperature known object brightness exceeds a predetermined threshold. And when emissivity changes, in order to maintain temperature measurement precision, the countermeasure by the following means 2 can be taken.

Mean 2: How to cope with change in emissivity with time. The best means is to replace an object having a known temperature with a new one. When the exchange is impossible and the change value of the emissivity can be estimated from the trend management data of the means 1, the following method may be used for correction. That is, in the following equation 17 (the above equation 5) for calculating the stray light amount J derived by the means 2 of the above feature 1, the equation 18 using the emissivity ε _x after change with time instead of the standard emissivity ε. Thus, the amount of stray light J is calculated.

…（式１７）

…（式１８）

... (Formula 17)

... (Formula 18)

  After calculating the stray light amount J, the procedure 5 and subsequent items of the above feature 1 are calculated according to the above-described calculation procedure, and the temperature after the stray light correction is calculated. FIG. 14 shows an example in which the correction calculation for the emissivity change with time is performed by this method. As shown in FIG. 14, when the emissivity of an object having a known temperature increases with time with respect to the reference emissivity of 0.86, the corrected temperature decreases. However, according to the temperature measurement device according to each embodiment, a correct output of 900 ° C. can be obtained by calculating using the above feature 4.

  That is, the temperature measuring device according to each embodiment has the feature 4, thereby reducing the influence of the emissivity of the temperature known object with the passage of time, etc., and improving the temperature measurement accuracy even for long-term use. Can be maintained.

Emissivity after change over time ε _x
It should be noted that the emissivity ε _x after time change used here can be derived as follows.
As described above, the means 1 records the difference between the furnace inner wall luminance and the temperature known object luminance in the field of view of the imaging device over a long period of time. At this time, the difference between the brightness of the part of the furnace where the change in emissivity with time is considered to be relatively stable and hardly changed, for example, the brightness of the furnace wall that has not been repaired or repaired for a long time, and the known temperature of the object is also included. Record. Hereinafter, this site is also referred to as “comparison site”. When the furnace inner wall is a comparison part, the furnace inner wall brightness recorded by the means 1 can be set as the brightness of the comparison part.

Here, the apparent luminance of the comparison portion is Gw, and the temperature known object luminance is Gt. That is, a change in the difference ΔG (= Gt−Gw) between the comparison site luminance Gw and the temperature-known object luminance Gt is recorded for a long period. Since the “apparent luminance G” measured by the imaging apparatus is expressed by the above equation 8, the initial temperature known object (Gt ₁ ), the initial comparison site (inner wall, etc.) (Gw ₁ ), and long-term elapsed The apparent luminances of the later known temperature object (Gt ₂ ) and the comparison part (Gw ₂ ) after a long period of time are as follows.

…（式Ａ１）

... (Formula A1)

In this formula A1, Et is the black body luminance of the temperature known object, Jt is the stray light amount of the temperature known object, ε _w , the emissivity of the comparison part, Ew is the black body luminance of the comparison part, and Jw is the comparison part. Is the amount of stray light. Here, since the comparison site is a site where the change in emissivity with time is relatively stable and considered almost unchanged, the emissivity of the comparison site becomes constant at ε _w before and after the elapse of the period. Further, by making the temperature at the time of measurement constant, the black body luminance Et of the known object does not change before and after the lapse of the period. Furthermore, since the in-furnace stray light condition is rarely changed, the stray light amount Jt of the known object and the stray light amount Jw of the comparison part do not change before and after the passage of the period.

From this equation A1, the initial luminance difference ΔG ₁ and the luminance difference ΔG ₂ after the elapse of the period are expressed by the following equations A2 and A3.

…（式Ａ２）

…（式Ａ３）

... (Formula A2)

... (Formula A3)

Therefore, the temporal change amount (ΔG ₂ −ΔG ₁ ) of the luminance difference ΔG can be calculated as in the following formula A4.

…（式Ａ４）

... (Formula A4)

From this formula A4, it can be seen that the amount of change in emissivity (ε _x −ε) of an object whose temperature is known is proportional to the amount of change in apparent luminance over time (ΔG ₂ −ΔG ₁ ).

Here, if the proportionality constant between (ε _x −ε) and (ΔG ₂ −ΔG ₁ ) is K (= Et−Jt), the proportionality constant K can be obtained as follows.

  Since Et is the black body luminance of an object whose temperature is known, it can be calculated from the known temperature value according to the above Equation 3. On the other hand, Jt is the amount of stray light received by an object whose temperature is known, and therefore can be calculated from the output L of the imaging apparatus using the above equations 4 and 5. Therefore, the proportionality constant K (= Et−Jt) can be obtained by performing these measurements and calculations in advance. Further, the equation A4 can be calculated as the following equation A5.

…（式Ａ５）

... (Formula A5)

Therefore, by substituting the calculated proportionality constant K and the temporal change amount of the apparent luminance difference (ΔG ₂ −ΔG ₁ ) into the equation A5, the emissivity ε _x of the temperature known object after the temporal change is obtained. Can do. In addition, since the comparison calculation after a long period of time is performed under the in-furnace condition for which the proportional constant K is calculated, Et and Jt can be kept unchanged. It can be used until it is exchanged.

Note that the emissivity ε _x of the temperature-known object after the change with time needs to be calculated using data in which the conditions in the furnace (temperature and stray light amount) are equivalent. Therefore, of the long-term data measured and recorded, the known thermometer temperature and the temperature of the comparison site (furnace wall inner surface, etc.) are almost the same as the initial stage, and the furnace operating conditions (furnace stray light conditions) are It is desirable to extract a large number of data in time zones that are substantially the same, and calculate the emissivity ε _x using the average value. It is also possible to test the certainty of the results by statistical methods based on the variance of the data.

3-1-5. Feature 5
Feature 5: Position of an object with a known temperature defined by the stray light quantity distribution in the furnace

The feature 5 will be described as follows.
As described above, in each embodiment, an object having a known temperature does not need to be disposed in the vicinity of the steel slab by using a wavelength that does not cause reflection / absorption by the furnace gas or the like. The stray light inside has a distribution according to the position. Therefore, in the temperature measurement device according to each embodiment, in order to further improve the measurement accuracy, the temperature known object is placed at a position where the stray light amount is equivalent to the stray light amount at the steel piece position. The restriction of the position of the temperature known object due to the stray light distribution or the like is defined by the following three conditions.

Condition 1: Position where the stray light amount is substantially the same as the position of the steel slab in the distribution of stray light in the furnace Condition 2: Position where the angle of the steel slab with respect to the measurement surface is not less than the angle at which the emissivity of the steel slab does not change Condition 3: Position where no flame is caught between the steel pieces

  Each condition will be described below.

Condition 1: A position where the stray light amount is almost the same as the position of the steel piece in the stray light distribution in the furnace. When there is a temperature distribution on the inner wall of the furnace, the vicinity of the inner wall of the furnace is strongly affected by the temperature of the nearby inner wall of the furnace. The amount of stray light may be different from the general part in the furnace. FIG. 15 shows the result of calculating the stray light amount based on the data of the inventors when some of the furnace wall temperatures are different. This is the stray light distribution when a part of the inner walls of the furnace is 1100 ° C. in a furnace maintained at a furnace inner wall temperature of 1200 ° C. The horizontal axis in FIG. 15 is the distance from the furnace wall at 1100 ° C. The amount of stray light in an area less than 0.25 m from the furnace inner wall is significantly different from the amount of stray light at other positions. Therefore, in the temperature measuring device according to each embodiment, the temperature known object is arranged at a position away from the furnace inner wall by 0.25 m or more, thereby reducing the influence of the stray light distribution in the furnace due to the temperature distribution of the furnace inner wall, Measurement accuracy can be further improved.

Condition 2: The position where the angle of the steel slab with respect to the measurement surface is equal to or greater than the angle at which the emissivity of the steel slab does not change. Generally, depending on the substance, the surface emissivity may vary depending on the radiation direction. This is illustrated, for example, in Figure 2.81 of the Chemical Engineering Handbook 3rd edition. On the other hand, in the temperature measurement device according to each embodiment, the temperature known object and the steel piece are placed in the same field of view of the imaging device, and correction calculation is performed by comparing the luminance. Therefore, in order to prevent the emissivity of the billet from changing with respect to the emissivity of the object with known temperature, the known temperature object is placed at a position where the angle of the billet with respect to the measurement surface is within the range where the emissivity does not change. Both must be within the field of view of the imaging device.

  The inventors who have come up with such problems use steel slabs (steel materials), place temperature-known objects at various angles, measure the temperature of the steel slabs by the method described above, and determine the size of the error. The angle limit was determined. As a result, as shown in FIG. 16, it was concluded that this angle should be 13 degrees or more.

  Therefore, in the temperature measuring device according to each embodiment, by placing a temperature known object at a position where the angle of the steel slab with respect to the measurement surface exceeds 13 degrees, the influence on the temperature measurement due to the change in the emissivity of the steel slab. The temperature measurement accuracy can be further improved.

Condition 3: A position where no flame is sandwiched between the steel pieces In each embodiment, since monochromatic light, for example, radiation having a wavelength of 1 μm, which avoids the emission spectrum of carbon dioxide and water vapor, which are thermal radiation gases in the combustion gas, is measured, Compared to a full-wavelength radiation type thermometer, it is less susceptible to flames. However, since the flame contains heat-radiating free radicals or the like, stray light correction errors may occur if the flame is interposed between the steel pieces. Therefore, in the temperature measurement device according to each embodiment, the influence of the flame is reduced by maintaining a positional relationship in which the flame is not sandwiched between the steel piece, the temperature known object, and the imaging device. This positional relationship is defined by the positional relationship between the slab of the furnace to which the present technology is applied and the flame. Specifically, as shown in FIG. 17, the horizontal distance from the measurement point (steel) to the end of the flame is X ₁ , the height from the measurement point to the flame bottom is Y ₁ , and the temperature from the measurement point to the temperature. When the horizontal distance to the known object is X ₀ and the height is Y ₀ , the position of the temperature known object is set so as to satisfy the following Expression 19.

…（式１９）

... (Formula 19)

  As described above, the position of the temperature known object, which is defined by the stray light distribution in the furnace, by combining the conditions 1 to 3, is shown as follows.

In other words, this position is
Condition 1: The distance from the inner wall of the furnace is 0.25 m or more,
Condition 2: The angle formed between the measured point and the temperature known object is 13 degrees or more with respect to the surface of the measured point,
Condition 3: The horizontal distance from the measured point to the end of the flame is X ₁ , the height from the measured point to the flame is Y ₁ , the horizontal distance from the measured point to the temperature known object is X ₀ , and the height is Y When it is set to ₀ , it is set so as to satisfy the above equation 19.

  An example of the position of this temperature known object is the shaded area in FIG. The temperature measurement device according to each embodiment can further improve the temperature measurement accuracy of the steel slab by arranging the temperature known object within this range.

The temperature measuring method used in each embodiment of the present invention has been described above.
Next, an example of a temperature measuring apparatus according to each embodiment that actually executes such a method will be described.

3-3. Example of Temperature Measuring Device Used in Each Embodiment As shown in FIG. 17, the temperature measuring device 100 measures the temperature of the steel slab F arranged in the heating furnace 1. In FIG. 17, the furnace which heats with the burner 2 is illustrated as the heating furnace 1, However, The heating furnace 1 which can apply the temperature measuring apparatus 100 which concerns on each embodiment is not limited to this example. . When the temperature measuring device 100 is used in each of the embodiments of the present invention, it is desirable to insert the imaging device 110 and the temperature known object 120 from the furnace side wall or the furnace ceiling. That is, in this case, the horizontal direction shown in FIG. 17 corresponds to the furnace width direction.

  As shown in FIG. 17, the temperature measurement device 100 includes an imaging device 110, a temperature known object 120, a calculation unit 130, a display unit 141, and a storage unit 142.

  The imaging device 110 is an example of a luminance measurement unit, and is arranged so that the steel piece F and the temperature-known object 120 can be captured in the same visual field. Although FIG. 17 shows a case where the imaging device 110 is inserted into the heating furnace 1, in this case, the imaging device 110 has a heat resistant structure. The imaging device 110 only needs to be able to image the inside of the heating furnace 1. For example, the imaging device 110 may be disposed outside the heating furnace 1 by providing a window in the heating furnace 1 with heat-resistant glass or the like. Is possible.

  In addition, the imaging device 110 includes, for example, a wavelength selection filter (not shown) so as to be able to capture the luminance of a predetermined wavelength so as to satisfy the above feature 1. This wavelength selection filter is an example of a wavelength selection unit, and transmits light of a predetermined wavelength. The wavelength selection unit is not limited to the wavelength selection filter. For example, the imaging device 110 can capture the luminance of all wavelength bands (or a predetermined wavelength band) that can be imaged, and the image analysis unit 131 can extract only light of a predetermined wavelength. In this case, the image analysis unit 131 also serves as a wavelength selection unit. In addition, as an image pickup element of the image pickup apparatus 110, an element that picks up only a single color luminance of a predetermined wavelength can be used. In this case, the imaging device 110 also serves as a wavelength selection unit.

  As such an imaging device 110, for example, a camera using an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used. For example, an IP (imaging plate) can be used. As long as the luminance value in the captured image can be accumulated, any configuration may be used. And from such an imaging device 110, the luminance value received by each pixel in the captured image is output as an electrical signal.

  On the other hand, the temperature-known object 120 is disposed at a position satisfying the above-described features 1, 2, and 5, and includes, for example, a protective tube and a thermometer inserted inside the protective tube. The protective tube is made of, for example, a material that satisfies the emissivity defined in the above feature 3. When the metal material is a steel slab F, examples of such a material include ceramic materials such as alumina, alumina / silica, silicon carbide, and quartz, and metal materials such as Inconel, Hastelloy, and stainless steel. Moreover, as a thermometer, contact-type thermometers, such as a thermocouple thermometer and a resistance thermometer, can be used, for example. Examples of the thermocouple thermometer include a platinum-platinum rhodium thermocouple, and examples of the resistance thermometer include a platinum resistance thermometer. However, these thermometers are appropriately changed according to the temperature of the heating furnace 1 and the temperature band to be measured. The temperature of the known temperature object 120 is output to the calculation unit 130 (stray light calculation unit 22).

  The calculation unit 130 analyzes the image captured by the imaging device 110 and calculates the temperature of the steel slab F from the monochromatic luminance of the steel slab F. At that time, the calculation unit 130 corrects this temperature as described above. Therefore, as shown in FIG. 17, the calculation unit 130 includes an image analysis unit 131, a stray light calculation unit 132, a stray light correction unit 133, a temperature calculation unit 134, an emissivity change unit 135, and a storage unit 136. Have

  The image analysis unit 131 analyzes a captured image (an image including a luminance value of a single wavelength) captured by the imaging device 110 and corresponds to an output value corresponding to the luminance value of the temperature known object 120 and a luminance value of the steel slab F. Output value to be calculated. Then, each of the image analysis units 131 outputs an output value for the temperature known object 120 to the stray light calculation unit 132, and outputs an output value for the brightness value of the steel piece F to the stray light correction unit 133. At this time, the image analysis unit 131 calculates the output value corresponding to the luminance value of the temperature known object 120 from the average value of a plurality of pixels, because the temperature known object 120 is arranged at the position having the characteristics 1 and 2. Similarly, an average value can be used for the steel slab F. Therefore, temperature calculation accuracy errors can be reduced.

  The stray light calculation unit 132 calculates the stray light amount J by executing the procedure 2 to the procedure 4 of the feature 1 based on the output value corresponding to the luminance value of the temperature known object 120. Note that the procedure 1 has already been processed, and the above formulas 1 and 2 are already recorded in the stray light calculation unit 132. The stray light calculation unit 132 uses the recorded formulas 1 and 2. Then, Step 2 to Step 4 are executed.

  The stray light correction unit 133 executes Step 5 and Step 6 of the above feature 1 based on the output value corresponding to the luminance value of the temperature-known object 120 and the stray light amount J calculated by the stray light calculation unit 132 to correct stray light. Then, the black body luminance of the steel slab F is calculated.

  Based on the black body luminance of the steel piece F calculated by the stray light correction unit 133, the temperature calculation unit 134 calculates the temperature of the steel piece F that has been subjected to stray light correction by executing the procedure 7 of the above feature 1. The calculation result is displayed on the display unit 141 or recorded in the storage unit 142. The display unit 141 includes, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display (PDP), a field emission display (FED), and an organic display. An electroluminescence display (organic EL, OELD: Organic Electroluminescence Display), a video projector, or the like can be used.

  On the other hand, the image analysis unit 131 further extracts an output value corresponding to the brightness of the furnace inner wall of the heating furnace 1 and outputs it to the emissivity changing unit 135. Then, the emissivity changing unit 135 calculates the furnace inner wall luminance from the output value, and records the difference between the furnace inner wall luminance and the temperature known object luminance in the storage unit 136. The emissivity changing unit 135 and the storage unit 136 execute the above feature 4 by using these pieces of information, and appropriately update the radiance of the temperature known object 120 used by the stray light calculation unit 132.

  Note that the arithmetic unit 130 may be configured by, for example, a general-purpose or dedicated computer. The computing unit 130 can be configured by causing the computer to execute a program that realizes the functions of the above-described configurations. The computer includes a CPU (Central Processing Unit), a recording device such as an HDD (Hard Disk Drive), a ROM (Read Only Memory), a RAM (Random Access Memory), and a LAN (Local Area Network). Communication devices connected to the computer, input devices such as a mouse / keyboard, magnetic disks such as flexible disks, optical disks such as various CDs (Compact Discs), MOs (Magneto Optical) disks, DVDs (Digital Versatile Discs), and semiconductors Drives that read and write to removable storage media such as memory, display devices such as monitors, speakers, headphones, etc. And an output device such as an audio output device. And this computer can implement | achieve the function of each structure of the calculating part 130 by running the program recorded on the recording device and the removable storage medium, or the program acquired via the network.

3-4. Example of Measurement by Temperature Measuring Device Used in Each Embodiment Next, the metal material is placed in a combustion furnace (an example of the heating furnace 1) by a temperature measuring device and a temperature measuring method according to each embodiment of the present invention. The example which measured the steel slab F surface temperature is shown. The combustion furnace used here has a length of 8 m (corresponding to the furnace width direction in the case of the heating furnace 1), a width of 2 m, and a height of 2 m, and the steel slab F is heated by LNG (Liquid Natural Gas). The steel piece F is approximately 5 m and has a thickness of 50 mm. The imaging device 110 used a CCD camera with 380,000 pixels. The CCD camera has a wavelength filter function, and using this wavelength filter function, single-wavelength radiation having a wavelength of 1.0 ± 0.2 μm was measured. At this time, since the wavelength filter function has a width of about ± 0.2 μm, the imaging device 110 actually measures only the radiated light having a wavelength of 0.8 to 1.2 μm. However, a wavelength having such a width can be regarded as a single wavelength for practical use and industrial use. Therefore, the imaging device 110 does not need to capture strict single-wavelength light, and only needs to capture light having a wavelength that can be regarded as an industrially single wavelength.

  A radiation thermometer tester was commissioned to test the relationship between the temperature of the thermometer test blackbody furnace and the output value of the CCD camera. The verification temperature range is 900 ° C to 1250 ° C. Using the obtained test data, fitting calculation is performed by the method of least squares, and the following expression 21 is obtained as a specific form of the characteristic expression 20 (the above expression 2) of the imaging device 110 in the stray light correction calculation procedure. It was.

…（式２０）

…（式２１）

... (Formula 20)

... (Formula 21)

  Here, G is the gain setting value of the CCD camera, SS is the shutter speed setting value, L is the output of the CCD camera, E is the luminance corresponding to the temperature of the black body furnace, and the temperature at which the test was performed , 900 ° C., 1000 ° C., 1100 ° C., 1200 ° C., and 1250 ° C., the values calculated by the Planck equation described above. As a specific calculation method, five coefficients in the equation were determined by a nonlinear least square method with E as a dependent variable and G, SS, and L as independent variables. This characteristic formula is specific to the CCD camera used in this embodiment, and must be created individually when the CCD camera model is different or when the imaging device 110 other than the CCD camera is used.

  As shown in FIG. 18, the CCD camera was inserted obliquely downward from the measurement port opened in the side wall of the furnace. The horizontal distance from the farthest measurement point (position 1) of the billet F to the camera is 6 m, and the height from the horizontal plane where the billet F is placed to the CCD camera is 1.6 m. This is a positional relationship in which no flame enters a line connecting the tip of the CCD camera and the farthest measurement point (position 1) of the steel piece F. The center line of the CCD camera is directed toward the center (position 2) of the steel slab F, specifically, the depression angle is 21 degrees. This dip angle is selected in order to keep the entire surface of the steel slab F, that is, from position 1 to position 3 in the field of view of the camera, and may be appropriately determined in consideration of the shape of the furnace and the position where the steel material is placed. Thus, the temperature measuring device 100 can measure the temperature distribution of the entire surface of the steel slab F by keeping the entire surface of the steel slab F within the field of view.

  The temperature known object 120 uses a thermocouple with a protective tube and has an outer diameter of 17 mm. This thermocouple with a protective tube is inserted horizontally at a position 0.2 m below the CCD camera tip, protrudes 0.3 m from the inner surface of the furnace wall into the furnace, and the tip is within the field of view of the CCD camera. . If the positional relationship is within the visual field of the CCD camera, it is not always necessary to insert it horizontally. Depending on the structure of the furnace, it may be advantageous in terms of strength to open the ceiling and insert it vertically. Since this thermocouple works as an object having a known temperature, the protective tube covering the outside must have a known emissivity. In this embodiment, an alumina / silica ceramic protective tube having an emissivity of 0.85 was used.

  In this example, since the emissivity of the steel slab F was 0.86, it is almost the same as the emissivity of the thermocouple protective tube, but the emissivity is different as long as it is within the range satisfying the above feature 3. It may be. The type of thermocouple used was a JISB type thermocouple. The type of thermocouple may be appropriately selected depending on the temperature used. Further, instead of the thermocouple, another temperature sensor such as a platinum resistance thermometer may be used.

  The viewing angle of the CCD camera is sufficiently large at 60 degrees on the left and right and 45 degrees on the top and bottom. The brightness of the inner wall of the furnace and the brightness of the surface of the thermocouple protection tube are stored for a long time by the storage unit 136 connected to the thermocouple, and the trend of the difference is managed to change the emissivity of the thermocouple protection tube over time. If the change is detected, the temperature known object emissivity used for the stray light calculation is corrected so that the difference in luminance is equal. In this correction, among the stored data, the furnace temperature is a certain temperature (in this embodiment, a range of 1190 ° C. to 1210 ° C.), and the temperature of the known temperature object is a certain temperature (this implementation). In the example, only the data in the range of 1170 ° C. to 1190 ° C. was extracted, and the heat radiation conditions in the furnace were equivalent.

  The luminance measurement range of the object having a known temperature in the CCD camera was a circular portion having a surface of about 10 mm in diameter, and an average value of about 200 pixels was measured. The temperature of the billet F is in the range from 900 ° C to 1250 ° C. Three points of position 1, position 2, and position 3 shown in FIG. 18 were measured. Position 1 is about 6 m in horizontal distance from the CCD camera, position 2 is about 4 m, and position 3 is about 2 m away.

  FIG. 19 shows the result of performing the stray light correction calculation by the temperature measuring device according to each of the above embodiments and comparing it with the temperature measured by the thermocouple thermometer embedded in each position of the steel slab F. In FIG. 19, the vertical axis represents the measured temperature obtained by performing the stray light correction calculation by the temperature measuring device according to each embodiment, and the horizontal axis represents the embedded thermocouple measured temperature. In addition, the solid line in FIG. 19 represents a line (horizontal axis = vertical axis) where the measured temperature by this method (after stray light correction) matches the measured temperature of the embedded thermocouple. As shown in FIG. 19, the measurement points at the respective positions 1 to 3 are located on the solid line, and the embedded thermocouple measured temperature and the measured temperature (after correction of stray light) by this method showed good agreement. Therefore, it can be seen that the temperature measuring device according to each embodiment can accurately measure the temperature of the steel slab F. In addition, the temperature measuring device according to each embodiment further measures the surface temperature distribution of the steel slab F by measuring the temperature at each location in the captured image of the steel slab F as in the positions 1 to 3. It is possible to measure with high accuracy.

3-5. Example of Effect by Temperature Measuring Device Used in Each Embodiment Finally, advantageous effect on Patent Documents 3 to 5 so that the effect by the temperature measuring method used in each embodiment of the present invention can be easily understood. An example will be described. However, it is needless to say that the effects described here are merely examples and do not limit the effects of the temperature measurement device according to each embodiment.

3-5-1. Patent Document 3
In the temperature measurement method described in Patent Document 3, a shielding plate is provided on the surface of the temperature measurement object to block stray light in the furnace. The shielding plate is cooled with water to prevent thermal radiation from the shielding plate itself. The error due to the radiation emitted by the shielding plate is obtained by actually measuring the temperature T _{2 of the} shielding plate and obtaining a corrected true temperature T ₁ from the apparent radiation energy G _{1 according} to the following equation 22. Eb (T) represents radiant energy at temperature T.

…（式２２）

... (Formula 22)

  In Patent Document 3, it is necessary to place a shielding plate near the steel piece. However, when the steel slab moves, the shielding plate may be damaged by the movement of the steel slab, for example, in a walking beam heating furnace. If a mechanism for moving the shielding plate according to the movement of the steel piece is provided, the measurement system itself becomes complicated. In addition, it is difficult to completely block stray light with the light shielding plate, and the accuracy may decrease depending on the path of stray light.

  On the other hand, in the temperature measurement method and the like described in each embodiment, there is no need to place a structure near the steel piece. Therefore, the temperature measurement method and the like described in each embodiment does not require the use of a shielding plate, a water cooling device, a complicated measurement system, or the like with respect to Patent Document 3, and measures the temperature with a simple device configuration. be able to. Further, in this temperature measurement method and the like, the amount of stray light is calculated and stray light correction is performed, so that the influence of stray light that cannot be blocked by the light shielding plate can be reduced, and high-precision temperature measurement is possible. .

3-5-2. Patent Document 4
In the temperature measurement method described in Patent Document 4, the surface temperature T corrected from the apparent temperature S of the radiation thermometer is obtained by the following equation representing the luminance L using the measured temperature Tw and the effective temperature Tw ′ of the furnace wall. .

…（式２３）

... (Formula 23)

  At this time, the furnace wall effective temperature Tw ′ is calculated by the primary expression 24 of the brightness of the actually measured temperatures Tw1, Tw2,... Twn of two or more thermometers installed on the furnace wall.

…（式２４）

... (Formula 24)

Coefficients a _1, a 2 of the linear expression, _... a _n is previously set to a value adapted to the dimensions of the pre-furnace body shape and steel by experiments or the like.

In Patent Document 4, stray light sources in the furnace are mainly a flame and a furnace wall. However, in this patent document 4, although the influence of the stray light from the furnace wall can be corrected to some extent, it is difficult to correct when the radiant energy from the flame changes. Stray temperature and size of the furnace or flame emanating always from the flame if constant heating furnace without using a flame, the coefficients a _1, a 2, _... is included as a constant value to a _n, if flame fluctuation The coefficients a ₁ , a ₂ ,... _An are considered to change. In general, in a heating furnace, the amount of combustion in the combustion device is appropriately adjusted in order to appropriately control the temperature in accordance with the amount of the object to be heated and the reached temperature, so that the flame state changes with time. On the other hand, Patent Document 2 does not show a correction means corresponding to a change in flame. Therefore, it is difficult to apply this Patent Document 4 to a heating furnace using a flame.

  On the other hand, in the temperature measurement method and the like described in each embodiment, the temperature known object is arranged in the furnace space so that both the stray light emitted from the furnace wall and the stray light emitted from the flame are irradiated to the temperature known object. Further, the positional relationship between the flame, the steel slab, and the temperature known object is defined as shown in the feature 5 above. Therefore, in the temperature measurement method and the like described in each embodiment, it is possible to perform appropriate correction even with respect to fluctuations in the radiant energy of the flame.

3-5-3. Patent Document 5
Patent Document 5 is as described in the related art, and the effects and the like according to each embodiment of the present invention have been described in detail in the above description, but the temperature measurement device according to each embodiment of the present invention further includes: An object having a known temperature is installed in the vicinity of the camera away from the steel slab, and imaging of monochromatic luminance at a wavelength at which absorption and emission by the furnace gas do not occur. While avoiding obstacles, it is possible to obtain a sufficient number of pixels by increasing the angle of view of a temperature known object, which is usually a small object, and to improve stray light correction accuracy.

  As mentioned above, although preferred embodiment of this invention was described in detail, referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  In the above-described embodiment, the features of the temperature measurement device and the like according to each embodiment of the present invention have been described separately from features 1 to 5 so that the features can be easily understood. However, these features 1 to 5 do not limit the features of the embodiments of the present invention, and the features of the embodiments of the present invention are described in detail in the features 1 to 5 described above. Needless to say, each feature is also included.

  In this specification, the steps described in the flowcharts are executed in parallel or individually even if they are not necessarily processed in time series, as well as processes performed in time series in the described order. Including processing to be performed. Further, it goes without saying that the order can be appropriately changed even in the steps processed in time series.

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Burner 3 Skid beam 4 Skid post 5 Partition wall 6 Local heating apparatus 10,20 Heating control apparatus 11 Position determination part 12 Temperature difference calculation part 13 Temperature difference memory | storage part 14,22 Judgment part 21 Temperature difference prediction part 23 Furnace Control unit 61, 62, 63, 64, 65, 66, 67 Burner 231 Furnace temperature control unit 232 Conveyance speed control unit 233 Local heating control unit 100 Temperature measurement device 100A, 100B, 100C, 100D, 100E Temperature measurement device 110 Imaging device DESCRIPTION OF SYMBOLS 120 Temperature known object 130 Calculation part 131 Image analysis part 132 Stray light calculation part 133 Stray light correction part 134 Temperature calculation part 135 Emissivity change part 136 Storage part 141 Display part 142 Storage part 200 Ambient temperature measuring device F Billet IN Inlet OUT Extraction Mouth Ar Temperature measurement area P1 1st position P2 2nd position

Claims (18)

A heating control device that controls a heating furnace that heats the metal material while conveying the metal material in the furnace length direction,
A plurality of temperature measuring devices that are arranged at a plurality of locations along the conveying direction of the metal material and measure the temperature distribution of the surface of the metal material passing therethrough,
On the surface of the metal material, it is expected that the temperature is higher than other positions and should be managed during the heating process, and the temperature is expected to be lower than other positions and managed during the heating process. A position determining unit for determining a second position to be performed;
A temperature difference calculating unit that calculates a temperature difference between the first position and the second position determined by the position determining unit based on the temperature distribution measured by each of the plurality of temperature measuring devices for each of the plurality of locations; ,
A determination unit that determines completion of heating of the metal material based on the temperature difference calculated by the temperature difference calculation unit;
A heating control device comprising:   The determination unit determines completion of heating of the metal material when the temperature difference calculated by the temperature difference calculation unit is equal to or less than a predetermined target temperature difference. The heating control device described.   The determination unit, when the temperature difference calculated by the temperature difference calculation unit once exceeds the target temperature difference in at least one of the plurality of locations and then becomes less than the target temperature difference, the metal difference The heating control apparatus according to claim 2, wherein the heating completion of the material is determined. Based on the temperature difference in at least two of the plurality of places calculated by the temperature difference calculation unit, the temperature difference between the first position and the second position in the metal material at the time of extraction from the heating furnace is calculated. It further has a temperature difference prediction unit for prediction,
The determination unit determines that heating of the metal material is completed at the time of extraction when the temperature difference predicted by the temperature difference prediction unit is equal to or less than the target temperature difference. Item 4. The heating control device according to Item 2 or 3.   The apparatus further includes a furnace temperature control unit that controls the furnace temperature of the heating furnace downstream of the temperature measurement devices arranged in the at least two locations based on the temperature difference predicted by the temperature difference prediction unit. The heating control device according to claim 4, wherein   Based on the temperature difference predicted by the temperature difference prediction unit, a local heating device arranged downstream of the temperature measuring device arranged in the at least two locations in the conveying direction is used, and a part of the metal material is locally heated. The heating control apparatus according to claim 4, further comprising a local heating control unit that controls the heating control unit to control the heating.   The heating control according to any one of claims 4 to 6, further comprising a conveyance speed control unit that controls a conveyance speed of the metal material based on the temperature difference predicted by the temperature difference prediction unit. apparatus.   The position determination unit is configured to determine the highest temperature position and the lowest temperature position in the surface of the metal material based on the temperature distribution measured by the temperature measurement device at one place close to the charging side of the heating furnace, respectively. The heating control apparatus according to claim 1, wherein the heating control apparatus determines the first position and the second position.   The position determining unit determines a maximum temperature position and a minimum temperature position at which an area occupying the surface of the metal material is a predetermined threshold or more as the first position and the second position, respectively. The heating control apparatus according to 8. The temperature measuring device is
A luminance measurement unit that measures at least the radiant energy distribution of the metal material by monochromatic luminance having a wavelength at which absorption and emission by the furnace gas do not occur;
A temperature known object for correcting stray light in the heating furnace, disposed in the vicinity of the luminance measuring unit within the measurement range of the luminance measuring unit,
A calculation unit that obtains a temperature distribution of the metal material by correcting stray light of the monochromatic luminance distribution of the metal material and the temperature known object measured by the luminance measurement unit;
The heating control apparatus according to claim 1, wherein: The computing unit is
When obtaining the temperature of the metal material, based on the radiant energy of the temperature known object and the temperature of the temperature known object, a stray light calculation unit that calculates the amount of stray light,
A temperature calculation unit that calculates a temperature distribution of the metal material based on the stray light amount calculated by the stray light calculation unit and a radiant energy distribution of the metal material;
The heating control device according to claim 10, characterized by comprising: The luminance measurement unit is an imaging device that captures a monochrome luminance distribution of radiant energy of the metal material and the temperature known object as an image of a predetermined number of pixels,
The heating control device according to claim 10 or 11, wherein the temperature known object is arranged at a position where an area occupying in an image captured by the imaging device is 25 pixels or more.   The heating control device according to claim 12, wherein the temperature known object is arranged at a position where an area occupying in an image captured by the imaging device is 100 pixels or more.   The heating control apparatus according to any one of claims 10 to 13, wherein an emissivity of the temperature known object is in a range of 0.1 before and after the emissivity of the metal material. The brightness measurement unit further measures the radiant energy of the inner wall of the heating furnace,
A storage unit in which a difference in radiant energy between the furnace inner wall and the temperature known object is recorded;
Based on the difference in the radiant energy recorded in the storage unit, an emissivity changing unit that grasps whether or not the emissivity of the temperature-known object changes with time,
The heating control apparatus according to any one of claims 10 to 14, characterized by comprising: The emissivity changing unit calculates the emissivity after the change with time when the elapse rate of the emissivity of the temperature known object occurs,
The heating control device according to claim 15, wherein the calculation unit performs the stray light correction using the emissivity after the change with time. The said temperature known object is arrange | positioned in the position which satisfy | fills at least any one among the conditions of the following (A), (B), and (C), It is characterized by the above-mentioned. Heating control device.
(A) In the stray light distribution in the furnace, the position away from the furnace wall by a distance where the stray light amount is substantially the same as the position of the metal material. (B) The angle of the metal material with respect to the measurement surface is the emissivity of the metal material. Position where angle does not change or more (C) Position where no flame is sandwiched between the metal materials A heating control method for controlling a heating furnace that heats the metal material while conveying the metal material in the furnace length direction,
A temperature measuring step of measuring a temperature distribution of the surface of the metal material passing by a plurality of temperature measuring devices respectively disposed at a plurality of locations along the conveying direction of the metal material;
On the surface of the metal material, it is expected that the temperature is higher than other positions and should be managed during the heating process, and the temperature is expected to be lower than other positions and managed during the heating process. A position determining step for determining a second position to be performed;
A temperature difference calculating step for calculating a temperature difference between the first position and the second position determined in the position determining step based on the temperature distribution measured by each of the plurality of temperature measuring devices for each of the plurality of locations;
A determination step of determining completion of heating of the metal material based on the temperature difference calculated in the temperature difference calculation step;
A heating control method characterized by comprising:

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