JP2010265535A - Heating furnace and heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating furnace and a heating method by which the temperature of skid marks at the lower face of a metallic material can be more correctly measured in the heating furnace, where a metallic material is conveyed by the skids. <P>SOLUTION: In the heating furnace, a metallic material therein is heated while being conveyed by a plurality of skids. The heating furnace 1 comprises: a temperature measurement device 100 arranged between the skids, and measuring the temperature distribution in the lower face of the metallic material F; and a temperature calculation part 12 calculating skid mark quantity ΔT from the temperature distribution. The temperature measurement device 100 comprises: a luminance measurement part 110 measuring the radiation energy distribution in the metallic material by monochromatic luminance having wavelengths at which absorption and radiation by gas in the furnace do not occur; a temperature-known body 120 arranged in the vicinity of the luminance measurement part 110 within a measurement range of the luminance measurement part 110, and compensating stray light; and a calculation part 130 subjecting the monochromatic luminance distribution measured by the luminance measurement part 110 to stray light compensating and obtaining the temperature distribution of the metallic material F. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heating furnace and a heating method for heating a metal material in the furnace while supporting the metal material by a plurality of skids and transporting 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 strips, rail members called multiple skids, such as a walking beam type, are used to continuously heat metal materials in various fields. Thus, a heating furnace for conveying a metal material is used. In such a heating furnace, a metal material is conveyed in the furnace longitudinal direction by a plurality of skids. This skid includes a fixed skid that is formed to extend in the furnace length direction and is fixed to the hearth, and a movable skid that is formed to extend in the same direction between the fixed skids and is movable up and down and back and forth. And a movable skid moves back and forth with a vertical motion, and conveys a metal material.

Japanese Patent Laid-Open No. 10-140246 JP 61-292528 A JP-A-62-22089 JP 2005-134153 A

  However, in a heating furnace that transports a metal material using a skid such as a walking beam type heating furnace, for example, a lower temperature called a “skid mark” is formed on the lower surface of the metal material in contact with the water-cooled skid. Parts are generated. In general, when a metal material is transported in a heating furnace, the temperature drop amount of the skid mark on the lower surface of the metal material in contact with the fixed skid that has a long loading time tends to increase. This skid mark is produced by radiant heat transfer to the skid, which has become low temperature due to cooling, or when the metal material is locally cooled by direct contact with the skid. For example, a continuous production of a hot-rolled steel strip In the case of a hot-rolling factory, the product quality is lowered and the yield is lowered, for example, cracking due to a decrease in product thickness accuracy, strength, and insufficient elongation in subsequent rolling. Therefore, great efforts have been made to eliminate such skid marks.

  For example, Patent Document 1 discloses a skid mark heating apparatus that heats a skid mark. In this skid mark heating device, an auxiliary combustible gas is supplied in the direction of the tip of the skid to locally heat the skid mark.

  However, even if such a heating device is used, it is often unclear how much the skid mark can be eliminated by heating. As a result, the skid mark cannot be properly eliminated, or a part that is partially hot due to excessive heating may occur.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to increase the temperature of the skid mark on the lower surface of the metal material in a heating furnace that conveys the metal material by a plurality of skids. It is to measure accurately.

In order to solve the above problems, according to one aspect of the present invention, a heating furnace that heats the metal material while supporting the metal material in the furnace by a plurality of skids and transporting the metal material in the furnace length direction,
At least one or more between the plurality of skids, and a temperature measuring device for measuring the temperature distribution of the lower surface of the metal material;
A temperature calculation unit that calculates a skid mark amount that is a difference between a temperature at a position between the skids of the metal material and a temperature at a position corresponding to the skid of the metal material from a temperature distribution measured by the temperature measuring device. When,
Have
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;
There is provided a heating furnace characterized by comprising:

  Moreover, you may further have a heating furnace control part which controls at least one of the conveyance speed of the said metal material, and the furnace temperature in the said heating furnace based on the skid mark amount computed by the said temperature calculation part.

  Moreover, you may further have a skid mark heating apparatus which heats the skid mark which is the position corresponding to the said skid of the said metal material based on the skid mark amount computed by the said temperature calculation part.

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 the emissivity of the metal material. Position where the angle does not change or more (C) Position where the combustion frame is not sandwiched between the metal material

Moreover, in order to solve the said subject, according to another viewpoint of this invention, it supports by the heating furnace which heats this metal material, supporting the metal material in a furnace by several skids, and conveying in a furnace length direction. Heating method,
A temperature measuring step of measuring a temperature distribution of the lower surface of the metal material by means of a temperature measuring device arranged at least one of the plurality of skids;
A temperature calculating step for calculating a skid mark amount that is a difference between the maximum temperature between the skids of the metal material and the minimum temperature at the corresponding position of the skid of the metal material from the temperature distribution measured in the temperature measuring step. When,
Based on the skid mark amount calculated in the temperature calculation step, a heating control step for controlling at least one of the conveyance speed of the metal material and the furnace temperature in the heating furnace,
Have
In the above temperature and temperature measurement step,
A temperature known object for correcting stray light in the heating furnace is installed in the vicinity of the luminance measuring unit,
Using the luminance measurement unit, by measuring the radiant energy of the metal material and the temperature known object by monochromatic luminance having a wavelength at which absorption and emission by the furnace gas do not occur,
A heating method is provided, wherein the measured monochromatic luminance is corrected for stray light to obtain a temperature distribution of the metal material.

  As described above, according to the present invention, the temperature of the skid mark on the lower surface of the metal material can be measured more accurately in the heating furnace in which the metal material is conveyed by a plurality of skids.

It is explanatory drawing for demonstrating the structure of the heating furnace which concerns on 1st Embodiment of this invention. It is explanatory drawing for demonstrating the structure of the heating furnace which concerns on the same embodiment. It is explanatory drawing for demonstrating the skid mark heating apparatus which the heating furnace which concerns on the same embodiment has. It is explanatory drawing for demonstrating the temperature measuring apparatus which the heating furnace which concerns on the same embodiment has. It is explanatory drawing for demonstrating the temperature measuring apparatus which the heating furnace which concerns on the same embodiment has. It is explanatory drawing for demonstrating the temperature measuring apparatus which the heating furnace which concerns on the same embodiment has. It is explanatory drawing for demonstrating the example of the skid mark amount calculation by the skid mark amount calculation part which concerns on the same embodiment. It is explanatory drawing for demonstrating the example of skid mark amount prediction and determination by the heating furnace which concerns on the same embodiment. It is explanatory drawing for demonstrating the example of skid mark amount prediction and determination by the heating furnace which concerns on the same embodiment. It is explanatory drawing for demonstrating operation | movement of the heating furnace which concerns on the same embodiment. It is explanatory drawing explaining the characteristic 2 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the characteristic 3 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the characteristic 3 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the characteristic 4 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the condition 1 of the characteristic 5 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining Condition 2 of the characteristic 5 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the characteristic 5 which the temperature measurement method used for the embodiment has. It is explanatory drawing explaining the Example of the temperature measuring method used for the embodiment. It is explanatory drawing explaining the Example of the temperature measuring method used for the embodiment. It is explanatory drawing for demonstrating the temperature measuring method which concerns on related technology. It is explanatory drawing for demonstrating the temperature measuring method 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, first, the first embodiment of the present invention will be described in the order of configuration, operation, and effect so that the embodiment of the present invention can be easily understood. On the other hand, the heating furnace according to the first embodiment of the present invention is, for example, a walking beam heating furnace, and further includes a temperature measurement device capable of measuring the temperature distribution on the surface of the metal material that is the material to be heated. In this temperature measuring device, a temperature measuring method capable of accurately measuring the temperature distribution on the surface of the metal material is used. By using this temperature measuring method and apparatus, the heating furnace according to the first embodiment of the present invention can exhibit its effects. Therefore, after describing the configuration of the heating furnace according to the first embodiment, the temperature measuring device and the like will be described in detail. In the following, for convenience of explanation, a walking beam type heating furnace will be described as an example. However, the heating furnace according to the first embodiment of the present invention is not limited to this example, and may be various heating furnaces. May be.

That is, the following will be described in the following order so that each embodiment of the present invention can be easily understood.
1. 1. First embodiment 1-1. Configuration of the heating furnace according to the first embodiment 1-2. Operation of the heating furnace according to the first embodiment 1-3. 1. Examples of effects according to the first embodiment Temperature measuring method and apparatus used in the first embodiment

  In the following, for convenience of explanation, a walking beam type “continuous billet 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 which concerns on each embodiment of this invention is not restricted to the said continuous steel slab heating furnace, Furthermore, it is not limited to the steel industry. That is, the metal material may be various metal materials that require heat treatment. Also, the heating furnace itself is not limited to the one using the walking beam type as a transfer device, and has a transfer mechanism that transfers a metal material while supporting it with a plurality of skids, and heats the metal material. It may be various ones commonly used in

1-1. Configuration of Heating Furnace According to First Embodiment FIGS. 1 and 2 are explanatory diagrams for explaining the configuration of the heating furnace according to the first embodiment of the present invention. 2 shows a cross-sectional view of the heating furnace 1 in FIG. 1 cut along the line AA.

  As shown in FIG. 1, the heating furnace 1 according to the present embodiment has a configuration for actually heating the steel slab F and a configuration for controlling heating by the configuration for heating. Therefore, first, a configuration for actually heating the steel slab F will be described, and then a configuration for controlling heating by the configuration will be described.

1-1-1. Configuration for actually heating the steel slab The heating furnace 1 is configured to actually heat the steel slab F, as shown in FIG. 1, with a burner 2, a walking beam as a conveying device, and a skid mark heating. And a device 5.

  As shown in FIG. 1, the heating furnace 1 heats a steel piece F while conveying a steel piece F that 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 steel piece F shown in FIG. 1 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. 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.

A walking beam is used as the transfer device.
As shown in FIG. 1, the walking beam type conveying apparatus is configured such that a skid beam 3 having a length approximately equal to the furnace length direction is supported by a plurality of skid posts 4, and a steel piece is placed 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. 2, a plurality of skids are arranged in the furnace width direction.

  The skid is classified into a movable skid and a fixed skid, and the movable skid and the fixed skid are alternately arranged as shown in FIG. The skid beam 3 and the skid post 4 of each skid are called a skid beam 3A and a skid post 4A if they are movable skids, and are called a skid beam 3B and a skid post 4B if they are fixed skids. .

  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 conveyed forward as the movable skid moves forward from the state supported by the skid beam 3A of the movable skid. Thereafter, when the movable skid moves downward, the steel piece F is supported by the skid beam 3B of 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.

  The vertical movement of the movable skid is controlled by a higher-level control device (not shown) or a conveyance speed control unit 161 of the heating control unit 10 described later, and is mainly performed in accordance with a heating schedule or the like.

  On the other hand, a plurality of burners 2 are arranged in the heating furnace 1. As a result of the burner 2 being cooked, the steel slab F is heated by a frame (flame) ejected from the burner 2 while being transported to the transport device, that is, in the furnace.

  In addition, in the heating furnace 1 shown in FIG.1 and FIG.2, in the up-down direction of the conveyance position of the steel slab F, 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.

  The combustion flow rates and the like of the plurality of burners 2 are controlled by a higher-level control device (not shown) or a furnace temperature control unit 162 of the heating control unit 10 described later, and are adjusted mainly according to the heating schedule and the like.

  On the other hand, the heating furnace 1 which concerns on this embodiment has a walking beam as a conveying apparatus as above-mentioned, and the steel piece F is conveyed when the movable skid of the walking beam moves up and down. When the steel slab F is transported, as shown in FIG. 2, the skid beam 3A of the movable skid or the skid beam 3B of the fixed skid is in contact with the lower surface of the steel slab F, while the skid beam 3 is heat resistant. In many cases, it is cooled by water cooling or the like in order to ensure this. As a result, the temperature at the position where the skid beam 3 is in contact with the lower surface of the steel slab F (also referred to as “skid mark portion SM”) is lowered as compared with other portions. The amount of temperature drop in the skid mark portion SM is also referred to as “skid mark amount ΔT”. When this skid mark amount ΔT is large, the deformation resistance of the skid mark portion SM becomes large, so that the product quality such as cracking due to a decrease in product thickness accuracy, strength and lack of elongation occurs in subsequent rolling, etc. Lead to a decrease in yield and yield.

  As described above, the heating furnace 1 is mainly adjusted by the upper control device or the heating control unit 10 or the like so that the transport speed of the steel slab F by the transport device and the combustion amount of each burner 2 are adjusted. The heating state is controlled. Therefore, the heating furnace 1 according to the present embodiment can reduce the skid mark amount ΔT by adjusting the transport speed and the combustion amount by the furnace control unit 16 and the like which will be described later. In addition to controlling the heating state, the heating furnace 1 according to this embodiment includes a skid mark heating device 5 that performs auxiliary heating in order to reduce the skid mark amount ΔT.

The skid mark heating device 5 will be described with reference to FIGS.
FIG. 3 is an explanatory diagram for describing a skid mark heating apparatus included in the heating furnace according to the present embodiment. FIG. 3 shows a cross-sectional view of the heating furnace 1 in FIG. 1 cut along the line BB.

  As shown in FIG. 1, the skid mark heating device 5 is arranged on the extraction side with respect to one or more temperature measuring devices 100 (desirably two or more temperature measuring devices 100A to 100C) as will be described later. . On the other hand, when viewed in the furnace width direction, the skid mark heating device 5 locally places the skid mark portion SM at a position corresponding to the skid beam 3B (skid beam 3A) of the steel piece F as shown in FIG. It is arranged to be heatable. The skid mark heating device 5 locally heats the skid mark part SM by generating a frame (flame) with respect to the skid mark part SM.

  FIG. 3 illustrates the case where the skid mark heating device 5 heats the skid mark portion SM corresponding to the skid beam 3B of the fixed skid. This is because the steel slab F is generally supported by the fixed skid longer than the time supported by the movable skid, and as a result, the skid mark portion SM corresponding to the fixed skid This is because the skid mark amount ΔT is larger than that of the movable skid. However, the skid mark heating device 5 may be arranged so as to heat the skid mark part SM of the movable skid, or arranged so as to heat both the skid mark part SM of the movable skid and the fixed skid. Needless to say, you can.

  In this embodiment, an auxiliary local heating burner inserted from the hearth is used as the skid mark heating device 5. However, the type of the burner is not particularly limited. For example, a roof burner that is inserted from the furnace ceiling and that heats the upper surface of the steel piece F corresponding to the skid mark portion SM, a heating device described in Patent Document 1, and the like are used. It is also possible to use it. When using a roof burner, the upper surface side of the skid mark part SM is locally heated by this roof burner, and the temperature of the skid mark part SM on the lower surface is increased by conduction heat transfer inside the steel slab F, so that the skid mark amount ΔT is reduced. It is possible to reduce.

  Furthermore, in the present embodiment, two sets of three burners in the furnace width direction are arranged in the furnace length direction. However, the number of burners is not particularly limited, and can be set as appropriate.

  The skid mark heating device 5 is controlled by an SM heating control unit 163 of the heating control unit 10 described later. At this time, the SM heating control unit 163 controls the combustion amount of at least one skid mark heating device 5 based on the skid mark amount ΔT calculated by the skid mark amount calculation unit 12 described later. The combustion control of the skid mark heating device 5 by the SM heating control unit 163 will be described in detail later.

1-1-2. Configuration for Actually Heating Steel Bill On the other hand, the heating furnace 1 includes a temperature measuring device 100 and a heating control unit 10 as a configuration for controlling heating, as shown in FIG.

  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.

  FIG. 1 illustrates a case where temperature measuring devices 100 are arranged at each of five locations along the transport direction. 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 one is arranged. And the arrangement | positioning position of the temperature measuring device 100 is not specifically limited, either, Each temperature measuring device 100 is arrange | positioned so that the temperature distribution of the lower surface of the steel slab F may be measured.

  Although the detailed configuration of the temperature measuring device 100 will be described later, the temperature measuring device 100 performs radiation temperature measurement and accurately measures the temperature distribution on the surface of the steel slab F. 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 lower surface of the steel slab F can be imaged.

  The arrangement position of each temperature measuring device 100 will be described more specifically with reference to FIGS. 4-6 is explanatory drawing for demonstrating the temperature measuring apparatus which the heating furnace which concerns on this embodiment has.

  As shown in FIG. 4, each temperature measuring device 100 is disposed between the plurality of skids below the steel piece F. At this time, it is desirable that the temperature measuring device 100 be disposed between the fixed skid and the movable skid near the center in the furnace width direction. In addition, in the temperature distribution measuring range (also referred to as “temperature measuring region Ar”) in which each temperature measuring device 100 measures the temperature distribution, as shown in FIG. The temperature measuring device 100 is arranged so as to include at least one of the skid mark portions SM corresponding to the skid beams 3A and 3B. In addition, it is desirable that this temperature measurement region Ar includes at least the skid mark portion SM on the side heated by the skid mark heating device 5, that is, the skid mark portion SM corresponding to the fixed skid in this embodiment.

  Moreover, as shown in FIGS. 1 and 4 to 6, the temperature measuring device 100 is arranged in a cover 150 inserted from the hearth toward the inside of the furnace. The cover 150 is formed of a heat-resistant material and has a water-cooled structure inside, and protects each component, wiring, and the like disposed inside from the temperature inside the heating furnace 1. On the other hand, the cover 150 is provided with a window, and the imaging device 110 of the temperature measurement device 100 images the lower surface of the steel piece F through the window, or the imaging device 110 of the temperature measurement device 100 protrudes from the cover 150. The lower surface of the steel slab F is imaged. On the other hand, the temperature known object 120 of the temperature measuring device 100 is disposed so as to protrude from the cover 150 and at least a part thereof is included in the temperature measuring region Ar. Each component of the temperature measuring device 100 will be described in detail later.

  The temperature measuring device 100 is controlled by the heating control unit 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 unit 10 always keeps track of which position the steel piece 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 part 10 may be sufficient. .

  Further, the temperature measurement result is recorded in the storage unit 142 of the heating control unit 10 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 part 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.

Next, the heating control unit 10 will be described.
As shown in FIG. 1, the heating control unit 10 includes a storage unit 142, a position determination unit 11, a skid mark amount calculation unit 12, a skid mark amount storage unit 13, and a skid mark amount prediction unit 14. Unit 15 and furnace control unit 16.

  The position determination unit 11 determines a reference 2 position on the lower surface of the steel slab F that is a temperature measurement target. These two positions are referred to as “first position P1” and “second position P2”. Both positions will be described with reference to FIG.

  In this embodiment, since the first position P1 and the second position P2 are expected to be relatively high or low compared to other positions during the surface temperature distribution of the steel slab F, they are managed during the heating process. Represents the position to be done. 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 rather than desired temperature. That is, the first position P1 and the second position P2 are, for example, positions that are desired to have the same temperature as other reference positions, and are higher or lower in temperature than the reference positions. It may be a 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 low temperature control point is a position corresponding to the skid beams 3A and 3B, that is, a position on the lower surface of the steel piece F in contact with the skid beams 3A and 3B. Therefore, this low temperature control point is also referred to as “skid upper temperature control point”. The high temperature control point is a position on the lower surface of the steel piece F between the skid beams 3A and 3B. Therefore, this high temperature control point is also referred to as an “inter-skid temperature control point”.

  The temperature control point on the skid and the temperature control point between the skids are free from problems in the processing after the heating process such as the rolling process. Therefore, the skid mark amount ΔT, which is the temperature difference between them, is less than a certain temperature. It is hoped that 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 temperature control point on the skid and the temperature control point between skids are positions where the temperature is relatively higher or lower than other positions as a result of both being higher or lower than the desired temperature. I can say that. 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 between the skids based on the operation results so far, and determines the second position P2 at a portion corresponding to the skid. 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 (coordinates on the lower surface of the steel slab F, etc.) are recorded in advance as the operation results. According to the heating control unit 10 according to the present embodiment, the position is specified based on the temperature distribution measurement result because the temperature measurement apparatus 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. As you accumulate. 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. Thereafter, the position determination unit 11 identifies one steel slab F from the database based on the characteristic information, and each of the high temperature position between the skids and the low temperature position corresponding to the skid associated with the steel slab F. Is determined to be the first position P1 or the second position 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 port IN, as compared with the other temperature measuring devices 100B to 100E. On the other hand, although depending on the heating performance by the heating furnace 1 and the like, the position with the highest temperature and the position with the lowest temperature on the lower surface of the charged steel slab F are the positions between the skids and the positions corresponding to the skids, respectively. In the heating process, it is expected that the temperature will be relatively high or low compared to other positions, or may be higher or lower than the desired temperature, resulting in higher or lower temperatures than other reference positions. is expected. Therefore, the position determination unit 11 corresponds to the highest temperature position between the skids (the position that is the highest temperature) and the skids in the lower surface of the steel slab F based on the temperature distribution measured by the temperature measuring device 100A on the charging side. The lowest temperature position (the position that is the lowest temperature) at the location is determined as the first position P1 and the second position P2, that is, the high temperature management point and the low temperature management 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 obtained as a result of the temperature measurement by the temperature measuring apparatus 100A. It is not necessary to have the highest and lowest temperatures above all locations.

  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 record for the billet F is in the database, the first position P1 and the second position P2 are determined based on the operation record, and when the operation record is not in the database, the determination is based on the actual measurement value. It is also possible to do. 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 to match the actual temperature distribution. Since the maximum temperature position and the minimum temperature position are 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.
As described above, the second position P2 is a position corresponding to the skid. Therefore, when the position of the lower surface of the steel piece F corresponding to both the movable skid and the fixed skid (both skid mark portions SM corresponding to both skids) is included in the temperature measuring region Ar of the temperature measuring device 100, The second position P2 is either the position of the lower surface of the steel piece F that contacts the skid beam 3A of the movable skid or the position of the lower surface of the steel piece F that contacts the skid beam 3B of the fixed skid.

  In the present embodiment, the skid mark heating device 5 manages the skid mark portion SM corresponding to the skid beam 3B of the fixed skid. As described above, the skid mark portion SM on the fixed skid side has a larger skid mark amount ΔT than the skid mark portion SM on the movable skid side. Therefore, the position determination unit 11 determines the second position P2 in the skid mark part SM of the fixed skid as described above, and thereby determines the second position P2 in the skid mark part SM on the side where the skid mark amount ΔT becomes larger. decide.

  The temperature measuring devices 100A to 100E sequentially perform temperature measurement at a timing at which the temperature at the position determined by the position determining unit 11 can be measured. That is, in the temperature measuring apparatuses 100A to 100E, when the second position P2 is determined on the skid mark portion SM of the fixed skid, the skid beam 3B of the fixed skid is not in contact with the lower surface of the steel piece F. Measure the temperature at the timing. On the other hand, in the temperature measuring apparatuses 100A to 100E, when the second position P2 is determined on the skid mark portion SM of the movable skid, the skid beam 3A of the movable skid is not in contact with the lower surface of the steel piece F. Measure the temperature at the timing. Therefore, it is desirable that each temperature measuring device 100A to 100E is input with information indicating the timing of the vertical movement of the movable skid from the control device of the transport device such as the transport speed control unit 161 described later.

The skid mark amount calculation unit 12 is an example of a temperature calculation unit, and the first position P1 and the first position 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. A skid mark amount ΔT, which is a temperature difference between the two positions P2, is calculated for each location where the plurality of temperature measuring devices 100A to 100E are arranged. For example, the temperature measurement device 100C will be described as an example. The skid mark amount calculation unit 12 stores a temperature distribution as a measurement result of the temperature measurement device 100C and information indicating the first position P1 and the second position P2. 142 and the position determination unit 11. Then, the skid mark amount 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 a temperature difference between them by the following formula A. Thus, the skid mark amount ΔT is obtained.
ΔT = T1-T2 (Formula A)

  The skid mark amount calculation unit 12 performs such calculation of the skid mark amount ΔT for each of the plurality of temperature measuring devices 100A to 100E. Then, the skid mark amount calculation unit 12 measures the skid mark amount ΔT with at least one of the temperature measuring devices 100A to 100E where the calculation is performed and the position in the transport direction (installation location of the temperature measuring device 100). It is recorded in the skid mark amount storage unit 13 in association with the steel piece F confidence.

  FIG. 7 shows an example of the calculation result of the skid mark amount ΔT by the skid mark amount calculation unit 12 for each position. FIG. 7 is an explanatory diagram for describing a skid mark amount calculation example by the skid mark amount calculation unit according to the present embodiment. In FIG. 7, the horizontal axis indicates the skid mark amount ΔT and the temperature measuring device 100 with respect to the skid mark amount ΔT, so that the positions of the temperature measuring devices 100A to 100E (positions in the x-axis direction) are given signs 100A to 100E. . 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. 7, it can be seen that the skid mark amount ΔT gradually increases to the position of the temperature measuring devices 100A and 100B and then decreases. The transition of the skid mark amount ΔT shown in FIG. 6 shows an example when the steel piece F is appropriately heated.

  The skid mark amount prediction unit 14 is an example of a temperature prediction unit, and predicts the skid mark amount ΔT of the steel slab F at the time of extraction. At this time, the skid mark amount prediction unit 14 predicts the skid mark amount ΔT at the time of extraction based on two or more skid mark amounts ΔT calculated by the skid mark amount calculation unit 12 from the measurement results of the temperature measuring devices 100A to 100E. To do.

  While the skid mark amount prediction unit 14 predicts the skid mark amount ΔT at the time of extraction, as shown in FIG. 6, the skid mark amount ΔT is expected to increase and then decrease. Therefore, it is often possible to improve the prediction accuracy by predicting the skid mark amount ΔT at the time of extraction based on the skid mark amount ΔT after starting to decrease. Therefore, it is desirable that the skid mark amount prediction unit 14 calculates the skid mark amount ΔT at the time of extraction based on the skid mark amount ΔT after the decrease.

  An example of a method of predicting the skid mark amount ΔT during extraction by the skid mark amount predicting unit 14 includes a method by extrapolation (extrapolation) based on two or more skid mark amounts ΔT other than during extraction. 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, if there is a track record of heating a steel slab F of the same or similar material and size at the same or similar conveying speed and combustion amount, the skid mark amount ΔT measured during the heating and the steel being heated By comparing the skid mark amount ΔT measured for the piece F, it is also possible to predict the skid mark amount ΔT at the time of extraction.

  Based on the skid mark amount ΔT calculated by the skid mark amount calculation unit 12 or the extraction-time skid mark amount ΔT predicted by the skid mark amount prediction unit 14, the determination unit 15 determines whether the heating of the steel piece F is performed during extraction. Determine if it is expected to be complete. That is, the determination unit 15 may perform determination based on the actually measured and calculated skid mark amount ΔT, or perform determination based on the skid mark amount ΔT at the time of extraction predicted from the measurement result. Also good.

At this time, various methods can be considered as the determination of the completion of heating.
As an example of determination based on actual measurement results, for example, the determination unit 15 determines that the skid mark amount ΔT measured and calculated on the extraction side is equal to or less than a predetermined target temperature difference (also referred to as an allowable limit temperature difference) ΔTc. In this case, the completion of heating of the steel slab F may be determined. In this embodiment, as shown in FIG. 7 etc., 25 degreeC is set as this target temperature difference (DELTA) Tc. Accordingly, the determination unit 15 determines that the heating of the steel slab F has been completed when the skid mark amount ΔT is 25 ° C. or less. For example, in the measurement example shown in FIG. 7, the skid mark amount ΔT at the time of extraction, that is, the skid mark amount ΔT corresponding to the temperature measuring device 100E is equal to or less than the target temperature difference ΔTc (25 ° C.). Determines that the steel slab F has been heated during extraction. On the other hand, unlike FIG. 7, when the skid mark amount ΔT corresponding to the temperature measuring device 100E exceeds the target temperature difference ΔTc (25 ° C.), the determination unit 15 has not completed heating (insufficient heating). Or overheating).

  As another example of the method for determining the completion of heating, as shown in FIG. 3, the determination unit 15 determines that the skid mark amount ΔT once exceeds the target temperature at least at one or more points, and then falls below the target temperature. In this case, it is possible to determine the completion of heating of the steel slab F. For example, the skid mark amount 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 herein, it is desirable to perform the heating completion determination based on the change state of the skid mark amount ΔT.

  The determination unit 15 can also make a determination based on the actually measured skid mark amount ΔT in this way, but can make a determination based on the skid mark amount ΔT of the prediction result by the skid mark amount prediction unit 14. Is also possible. In this case, the determination unit 15 determines that heating is completed during extraction when the predicted skid mark amount ΔT during extraction is equal to or less than the target temperature difference ΔTc.

  The prediction of the skid mark amount ΔT during extraction by the skid mark amount prediction unit 14 and the determination example by the determination unit 15 using the predicted skid mark amount ΔT will be described with reference to FIGS. 8 and 9. FIG. 8 and FIG. 9 are explanatory diagrams for explaining a skid mark amount prediction and determination example by the heating furnace according to the present embodiment.

  In FIG. 8, the steel piece at the time of extraction (when reaching the extraction port OUT) is determined by the skid mark amount prediction unit 14 based on the skid mark amount ΔT (black circle in FIG. 8) by the temperature measuring devices 100B to 100D. An example in which the skid mark amount ΔT of F (white circle in FIG. 8) is predicted is shown. In this example, the predicted skid mark amount ΔT (◯) is calculated to be higher than the target temperature difference ΔTc (for example, 25 ° C.). Therefore, in this case, the determination unit 15 determines that the steel piece F is not completely heated during extraction.

  In FIG. 9, based on the skid mark amount ΔT (black circle in FIG. 8) by the temperature measurement device 100 </ b> B and the temperature measurement device 100 </ b> C, the skid mark amount prediction unit 14 performs the extraction (when the extraction port OUT arrives). The example which estimated skid mark amount (DELTA) T (white circle in FIG. 8) of the steel piece F is shown. Also in this example, the predicted skid mark amount ΔT (◯) is calculated to be higher than the target temperature difference ΔTc (for example, 25 ° C.). Therefore, in this case, the determination unit 15 determines that the steel piece F is not completely heated during extraction.

  And when the determination part 15 determines with heating not being completed, it outputs the instruction | indication that the heating adjustment of the steel slab F is required to the furnace control part 16. FIG. In addition, the furnace control part 16 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 measurement apparatus 100E just before extraction. Therefore, it is desirable that the skid mark amount prediction unit 14 performs the same heating completion determination again based on the skid mark amount ΔT of the temperature measuring device 100E. The determination result by the determination unit 15 is preferably recorded in an external storage device or displayed on an external display device.

  The furnace control unit 16 adjusts the heating state of the steel slab F by the heating furnace 1 based on the skid mark amount ΔT predicted by the skid mark amount prediction unit 14 so that the determination result by the determination unit 15 indicates the completion of heating. To do. At this time, the furnace control unit 16 may determine how to adjust the heating state based on the temperature distribution in which the temperature measuring device 100 has completed the measurement. The furnace control unit 16 according to the present embodiment uses at least one of “furnace temperature adjustment by the burner 2”, “adjustment of the conveyance speed”, and “local heating by the SM heating control unit 163” as a heating adjustment method. Which of these three heating adjustments is performed is determined by the furnace controller 16 based not only on the predicted skid mark amount ΔT but also on the temperature distribution measured by each temperature measuring device 100, energy efficiency, heating deadline, and the like. It is desirable to decide. In order to perform each heating adjustment, the furnace control unit 16 includes a conveyance speed control unit 161, a furnace temperature control unit 162, and an SM heating control unit 163 as shown in FIG. Each heating adjustment method and adjustment examples will be described in each configuration, and these configurations will be described below.

  The transport speed control unit 161 controls the transport speed of the steel slab F by the transport device based on the skid mark amount ΔT predicted by the skid mark amount prediction unit 14. That is, the conveyance speed control unit 161 adjusts the in-furnace time in the soaking zone for each steel slab F. At this time, the conveyance speed control unit 161 may determine how much the conveyance speed is to be adjusted based on the predicted skid mark amount ΔT, but is further provided separately in each section of the heating furnace 1. You may also refer to the furnace atmosphere temperature measured by the ambient temperature measuring device (not shown). It is desirable that the adjustment amount of the conveyance speed is determined in accordance with the skid mark amount ΔT and the temperature distribution based on the operation results, the adjustment results, the experiment results, and the like.

  In the heating adjustment example shown in FIG. 8, since the predicted extraction skid mark amount ΔT exceeds the target temperature difference ΔTc, the transfer speed controller 161 determines the adjusted transfer speed from the difference or the like, The transfer device (movable skid or the like) is controlled so that the transfer speed (for example, 1/2 times) is obtained. As a result, the skid mark amount ΔT (black circle (●)) in the case where the heating adjustment is performed is reduced to the target temperature difference ΔTc or less immediately before the extraction, as compared with the case where the heating adjustment by the conveyance speed adjustment is not performed. . In the example shown in FIG. 8, the reason why the skid mark amount ΔT is reduced by adjusting the conveyance speed is that the in-furnace time becomes long and the temperature is high by decreasing the conveyance speed. Has a small difference from the furnace temperature and a slow heating rate, while the second position P2 has a large difference from the furnace temperature, so the heating speed is faster than the first position P1. This is probably because the temperature of the piece F has become uniform. The conveyance speed control unit 161 adjusts at least one of the time during which the steel slab F is supported by the fixed skid and the time during which the steel slab F is supported by the movable skid, and adjusts the ratio of both times. By doing so, it is also possible to perform heating adjustment.

  When heating adjustment by the conveyance speed control unit 161 is performed, it is not necessary to increase the fuel flow rate of the burner as compared with other heating adjustments, and thus an increase in energy consumption can be suppressed, and a skid mark heating device Therefore, the heating furnace 1 or the heating control device 20 can be configured easily and at low cost. Note that a lower limit is provided as the target temperature difference ΔTc, and when the predicted skid mark amount ΔT falls below the lower limit, the transport speed control unit 161 may control the transport device so that the transport speed increases.

  On the other hand, the amount of skid mark ΔT can be reduced by the furnace temperature control unit 162 adjusting the furnace temperature. The furnace temperature control unit 162 will be described as follows.

  The furnace temperature control unit 162 is based on 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 skid mark amount ΔT predicted by the skid mark amount prediction unit 14. Also controls the furnace temperature of the heating furnace 1 (that is, soaking zone) downstream in the conveying direction. Then, the furnace temperature control unit 162 determines how much the atmospheric temperature needs to be adjusted based on the predicted skid mark amount ΔT and the atmospheric temperature in the furnace, and adjusts the atmospheric temperature by the determined amount. Therefore, the fuel flow rate of the burner 2 is adjusted. At this time, the furnace temperature control unit 162 may also refer to the furnace atmosphere temperature measured by a separate atmosphere temperature measurement device (not shown) arranged in each section of the heating furnace 1. The adjustment amount of the combustion flow rate is desirably determined in accordance with the skid mark amount ΔT and the temperature distribution based on the operation results, the adjustment results, the experimental results, and the like.

  In addition, as an example of the heating adjustment by the furnace temperature control unit 162, for example, in the section where the furnace temperature is adjusted, the combustion amount of the burner 2 below the steel slab F is lowered to lower the furnace temperature of the lower belt. Can be considered. When the furnace temperature of the lower belt is lowered in this way, the temperature of the steel slab F between the skids that is easily affected by the furnace temperature is lowered. As a result, the skid mark amount ΔT can be reduced.

  When the heating adjustment by the furnace temperature control unit 162 is performed, the conveyance speed is not reduced compared to other heating adjustments, so that not only the productivity is not reduced but also the skid mark heating device 5 is not required to be cooked. Therefore, the skid mark amount ΔT can be reduced easily and at low cost.

  Furthermore, the skid mark amount ΔT can be reduced by directly heating the skid mark portion SM by the SM heating control unit 163. The SM heating control unit 163 will be described as follows.

  The SM heating control unit 163 is transported more than the temperature measurement device 100 (for example, the temperature measurement device 100C) that measures the temperature distribution used for the prediction based on the skid mark amount ΔT predicted by the skid mark amount prediction unit 14. The skid mark heating device 5 disposed downstream in the direction is controlled so as to locally heat the skid mark part SM on the lower surface of the steel slab F. At this time, the SM heating control unit 163 may determine how much to heat based on the predicted skid mark amount ΔT, but further, an atmospheric temperature measuring device arranged in each section of the heating furnace 1. You may also refer to the furnace atmosphere temperature measured by (not shown). It is desirable that the amount of heating is determined in accordance with the skid mark amount ΔT and the temperature distribution based on the operation results, adjustment results, experimental results, and the like.

  In the heating adjustment example shown in FIG. 9, the predicted extraction skid mark amount ΔT exceeds the target temperature difference ΔTc. The part SM is locally heated. As a result, the skid mark amount ΔT (black circle (●)) in the case where the heating adjustment is performed decreases to a value equal to or less than the target temperature difference ΔTc immediately before the extraction, as compared with the case where the heating adjustment by the local heating is not performed. To do.

  When the heating adjustment by the SM heating control unit 163 is performed, it is possible to locally heat only the skid mark part SM of the target steel piece F compared to other heating adjustments, and thus other steel pieces. Less influence on F.

The configuration of the heating furnace 1 according to the first embodiment of the present invention has been described above.
Next, the operation of the heating furnace 1 according to the first embodiment of the present invention will be described with reference to FIG.

1-2. Operation of Heating Furnace According to First Embodiment FIG. 10 is an explanatory diagram for explaining the operation of the heating furnace according to the present embodiment.
As shown in FIG. 10, when the steel slab F is charged into the heating furnace 1 from the charging inlet IN, first, step S101 is processed.

  In step S101 (an example of a temperature measurement step), the temperature measurement device 100A arranged on the loading inlet IN side 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 S103.

  In step S103 (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 from the temperature distribution, the maximum temperature position between skids, and the skid mark The lowest temperature position in the part SM is extracted and determined as the first position P1 and the second position P2, respectively. In addition, when the determination of the 1st position P1 and the 2nd position P2 is performed based on the operation performance etc., said step S101 is omissible. In this case, in step S103, the position determination unit 11 accesses a 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 each of them is the first position P1. And the second position P2. After the process of step S103, the process proceeds to step S105.

  In step S105 (an example of a temperature calculation step), the skid mark amount calculation unit 12 acquires a temperature distribution for which the skid mark amount ΔT is to be calculated, and the temperature between the first position P1 and the second position P2 in the temperature distribution. The skid mark amount ΔT, which is the difference, is calculated based on the above equation A. That is, in this step S105, the skid mark amount ΔT is calculated for each of the temperature distributions measured in step S101 or step S109 described later (temperature distributions measured by any of the temperature measuring devices 100A to 100E). The calculated skid mark amount ΔT is recorded in the skid mark amount storage unit 13 for each steel piece F as described above. After the process of step S105, the process proceeds to step S107.

  In step S107 (an example of a temperature prediction step), the skid mark amount prediction unit 14 determines that the number of data that can be predicted for the skid mark amount ΔT at the time of extraction (that is, the skid mark amount ΔT of the temperature measuring devices 100A to 100C, for example) It is confirmed whether or not it is recorded in the mark amount storage unit 13. If the number of data necessary for temperature prediction is not complete, the process proceeds to step S109. If the necessary number of data is complete, the process proceeds to step S111.

  In step S109 (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 S101, and the temperature distribution is stored in the storage unit 142. Will be recorded. And the process of step S105-step S109 is repeated.

  On the other hand, in step S111 (an example of a determination step), whether or not the determination unit 15 is predicted to complete heating of the steel slab F based on the prediction result of the skid mark amount ΔT by the skid mark amount prediction unit 14. To check. When it is predicted that the heating is completed, that is, the extraction skid mark amount ΔT is equal to or less than the target temperature difference ΔTc, the operation is terminated without performing the heating adjustment in step S115. On the other hand, when the extraction skid mark amount ΔT exceeds the target temperature difference ΔTc, the process proceeds to step S115. The determination result prediction may be recorded on an external recording device or displayed on an external display device.

  In step S115, the furnace control unit 16 adjusts the heating state of the heating furnace 1. At this time, the furnace control unit 16 determines which of the three adjustment examples (combination or all of them) is used based on the predicted skid mark amount ΔT, energy efficiency, heating time limit, and the like. The adjustment amount in the selected adjustment method is also determined by each of the conveyance speed control unit 161, the furnace temperature control unit 162, and the SM heating control unit 163 of the furnace control unit 16 based on the predicted skid mark amount ΔT and the like. Heating adjustment is performed. After the process of step S115, the operation ends.

1-3. Examples of Effects According to First Embodiment The configuration and operation of the heating furnace 1 according to the first embodiment of the present invention have been described above.
According to the heating furnace 1, the skid mark amount ΔT can be obtained from the temperature distribution of the lower surface of the steel slab F in the temperature measuring region Ar of each of the temperature measuring devices 100A to 100E. The temperature measuring devices 100A to 100E can measure an accurate temperature distribution as will be described later. Therefore, the heating furnace 1 according to the present embodiment can calculate a more accurate skid mark amount ΔT.

  Further, the heating furnace 1 according to the present embodiment can determine whether or not the steel piece F can be extracted based on the skid mark amount ΔT. When determining whether or not extraction is possible based on the accurately measured skid mark amount ΔT, it is based on actual measurement values by the temperature measuring devices 100A to 100E, and compared with determination based on simulation or determination based on the atmospheric temperature of the heating furnace 1, Whether or not the steel piece F can be extracted can be determined more accurately.

  Furthermore, the heating furnace 1 according to the present embodiment predicts the skid mark amount ΔT at the time of extraction from the skid mark amounts ΔT corresponding to the plurality of temperature measuring devices 100, and based on the prediction result, the skid mark at the time of extraction Heating adjustments can be made so that the amount ΔT is reduced. Therefore, it is possible to prevent the occurrence of defects due to the skid mark, and to improve the yield while maintaining the product quality.

  Note that the heating control unit 10 of the heating furnace 1 according to the first embodiment may be configured by, for example, a general-purpose or dedicated computer. And the heating control part 10 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 can implement | achieve the function of each structure of the heating control part 10 by running the program recorded on the recording device and the removable storage medium, or the program acquired via the network.

2. Temperature measuring method and apparatus used in the first embodiment Next, a temperature measuring method and apparatus used in the first embodiment of the present invention will be described. As described above, the temperature measurement method and apparatus described here can measure the temperature distribution very accurately compared to other temperature measurement methods and apparatuses. By accurately measuring the surface temperature distribution in this way, the heating control method and apparatus according to the first embodiment of the present invention can achieve the effects described above. Therefore, the temperature measuring method and apparatus will be described in detail below with reference to FIGS.

  In the first embodiment of the present invention, the temperature measurement device is disposed between the skids on the lower surface side of the steel slab F. Here, the temperature measurement is performed so that the temperature measurement device can be easily understood. A case where the apparatus is arranged on the furnace side wall will be described as an example. Basically, if the temperature measuring device arranged on the furnace side wall described below is arranged between the skids, it can be applied to the first embodiment of the present invention.

  In the following, in order to make it easier to understand how this temperature measurement method and apparatus can measure the temperature distribution more accurately than other temperature measurement methods and apparatuses according to related technology, The related technique will be described, and then the temperature measurement method used in the first embodiment of the present invention will be described. Then, after describing the configuration and the like of the temperature measurement device for realizing this method, an example of the temperature measurement method and device used in the first embodiment will be described. Furthermore, an example of the effect of the temperature measuring method and apparatus used in the first embodiment will be described in comparison with Patent Documents 2 to 4.

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

2-1. Related Technology A related technology will be described with reference to FIGS. 20 and 21 are explanatory diagrams for explaining a temperature measurement method according to the related art.

  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 4 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 finding that the effect can be remarkably improved when used in the heating furnace and method according to the first embodiment. Completed the invention.

2-2. Outline of Temperature Measuring Method Used in First Embodiment Hereinafter, an outline of the temperature measuring method according to the first embodiment of the present invention will be described.
This temperature measuring method has the following features 1 to 3 roughly based on the temperature measuring method 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 measurement method according to the present embodiment will be described while sequentially explaining these features.

2-1-1. 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 measurement method according to the present 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 both are separated as in the present embodiment, the equality of stray light amounts is not necessarily guaranteed.

  Therefore, in the method of the present embodiment, the following means are roughly used in order to ensure the equality of the stray light amount 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 the present 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 is separated. As in this 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 this embodiment, for example, a wavelength of 1 μm is used as the measurement wavelength λ, and an optical filter can be used to select 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 the present 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 the present embodiment, the measurement wavelength λ is set to a wavelength with less 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 this 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 this embodiment that performs single wavelength measurement is used, even if a temperature known object is placed at a position where there is a slight difference in stray light, temperature measurement can be performed without greatly reducing accuracy. is there. That is, it is not necessary to place an object with a known temperature in the vicinity of the steel slab.

2-1-2. 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 this 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 this 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 method according to the present embodiment, the measurement error of the imaging apparatus can be reduced and the temperature measurement accuracy can be improved.

2-1-3. 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 the present 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 technique, the positional relationship between the steel slab and the known temperature object is not clearly shown, but in the figure # illustrated as an example, the known temperature object is placed near 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 this embodiment, by regulating 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 6 m point, the error is small. Measurement is possible.

  The features 1 to 3 included in the temperature measurement method according to the first embodiment of the present invention have been described above. The temperature measurement method according to this embodiment has the following features 4 and 5 in addition to the above features 1 to 3 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.

2-1-4. 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 measurement method according to the present 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 method according to the present embodiment, an output with a correct temperature of 900 ° C. can be obtained by calculating using the above feature 4.

  That is, the temperature measurement method according to the present embodiment has the feature 4 to reduce the influence of the emissivity of the temperature known object over time, etc., and improve 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.

2-1-5. 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 this embodiment, the object whose temperature is known does not need to be arranged in the vicinity of the steel slab by using a wavelength that does not cause reflection or absorption by the gas in the furnace or the like. The stray light inside has a distribution according to the position. Therefore, in the temperature measurement method according to the present embodiment, 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 in order to further increase the measurement accuracy. 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 measurement method according to the present embodiment, the influence of the stray light distribution in the furnace due to the temperature distribution of the furnace inner wall is reduced by arranging the temperature known object at a position separated by 0.25 m or more from 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 method according to this embodiment, a temperature-known object and a steel piece are placed in the same field of view of the imaging apparatus, 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 measurement method according to the present embodiment, by placing a temperature known object at a position where the angle with respect to the measurement surface of the steel slab 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: Position where no flame is sandwiched between the steel pieces In this embodiment, since monochromatic light, for example, radiation having a wavelength of 1 μm, which avoids the radiation 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 method according to the present 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 known temperature 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 method according to the present embodiment can further improve the temperature measurement accuracy of the steel slab by arranging the temperature known object within this range.

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

2-3. Example of Temperature Measuring Device Used in First 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 heating furnace 1 is exemplified by a furnace that performs heating with a burner 2 (an example of various burners such as a regenerative burner, a side burner, a roof burner, and an axial flow burner). The heating furnace 1 to which the measuring apparatus 100 can be applied is not limited to this example. When the temperature measuring device 100 is used in the first embodiment 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.

2-4. Example of Measurement Using Temperature Measuring Device Used in First Embodiment Next, in the combustion furnace (an example of the heating furnace 1) as a metal material by the temperature measuring method and the temperature measuring device according to the first embodiment of the present invention. The example which measured the arranged 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 measurement method according to the present embodiment 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 method according to the present 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 measurement method according to the present embodiment can accurately measure the temperature of the steel slab F. In addition, the temperature measurement method according to the present 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.

2-5. Example of Effect by Temperature Measuring Device Used in First Embodiment Finally, it is advantageous over the above Patent Documents 2 to 4 so that the effect by the temperature measuring method used in the first embodiment of the present invention can be easily understood. Examples of various effects 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 method according to the present embodiment.

2-5-1. Patent Document 2
In the temperature measurement method described in Patent Document 2, a shielding plate is provided on the surface of the temperature measurement object to block the 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 2, 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 this embodiment, there is no need to place a structure near the steel piece. Therefore, the temperature measurement method and the like described in the present embodiment do not require the use of a shielding plate, a water cooling device, a complicated measurement system, or the like with respect to Patent Document 2, and measures 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. .

2-5-2. Patent Document 3
In the temperature measurement method described in Patent Document 3, the surface temperature T corrected from the apparent temperature S of the radiation thermometer is obtained by the following expression 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 3, stray light sources in the furnace are mainly a flame and a furnace wall. However, in this patent document 3, although the influence of the stray light from the furnace wall can be corrected to some extent, it is difficult to correct when the radiation 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 3 to a heating furnace using a flame.

  On the other hand, in the temperature measurement method and the like described in the present 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 described in the present embodiment, it is possible to appropriately correct the fluctuation of the radiant energy of the flame.

2-5-3. Patent Document 4
Patent Document 4 is as described in the related art, and the effects and the like according to the first embodiment of the present invention have been described in detail in the above description. However, the temperature measurement device according to the first embodiment of the present invention is Furthermore, by installing a known temperature object in the vicinity of the camera away from the steel slab, and imaging the monochromatic luminance at a wavelength at which absorption and emission by the furnace gas do not occur, the steel slab described in Patent Document 2 is moved. While avoiding various 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 the 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.

  For example, in the above embodiment, the case where one temperature measuring device 100 is arranged in the furnace width direction as shown in FIG. 4 has been described. However, it is also possible to provide the temperature measuring device 100 in the furnace width direction and measure the temperature distribution in the entire lower surface of the steel slab F and obtain the skid mark amount ΔT from the measurement result. At this time, it is also possible to calculate the skid mark amount ΔT of the plurality of skid mark portions SM over the longitudinal direction of the steel slab F, and to perform the extraction determination and the heating adjustment based on the plurality of skid mark amounts ΔT. is there. In this case, it is possible to further improve the accuracy in the longitudinal direction of the steel slab F for the extraction possibility determination and the heating adjustment.

  Moreover, in the said embodiment, the case where the local heating burner inserted from the hearth and the roof burner was used as the skid mark heating apparatus 5 was demonstrated. However, the skid mark heating device 5 is not particularly limited to these burners. For example, it is possible to use a local heating device arranged in each skid or a heating device that heats the skid itself.

  Moreover, in the said embodiment, the case where the furnace control part 16 performed a heating adjustment based on skid mark amount ΔT at the time of extraction predicted by the skid mark amount prediction unit 14 was described. However, the furnace control unit 16 can also perform the heating adjustment based on the skid mark amount ΔT actually measured without performing temperature prediction, for example. In this case, the furnace control unit 16 acquires the skid mark amount ΔT corresponding to each temperature measuring device 100 recorded in the skid mark amount storage unit 13, and appropriately determines the transport speed according to the value of the skid mark amount ΔT. -It is possible to control the furnace temperature, local heating to the skid mark part SM, and the like. In this case, the skid mark amount prediction unit 14 and the determination unit 15 are not necessarily required.

  In the above embodiment, the features of the temperature measurement method and the like according to the first embodiment of the present invention have been described separately from the 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 first embodiment of the present invention, and the features of the first embodiment of the present invention are described in detail in each of the features 1 to 5. Needless to say, each described 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, 3A, 3B Skid beam 4, 4A, 4B Skid post 5 Skid mark heating apparatus 10 Heating control part 11 Position determination part 12 Skid mark quantity calculation part 13 Skid mark quantity storage part 14 Skid mark quantity prediction part DESCRIPTION OF SYMBOLS 15 Determination part 16 Furnace control part 100 Temperature measurement apparatus 100A, 100B, 100C, 100D, 100E Temperature measurement apparatus 110 Imaging apparatus 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 unit 136 storage unit 141 display unit 142 storage unit 150 cover 161 transport speed control unit 162 furnace temperature control unit 163 SM heating control unit F billet IN loading port OUT extraction port Ar temperature measurement region P1 first position P2 second position

Claims (11)

A heating furnace that heats the metal material while supporting the metal material in the furnace with a plurality of skids and transporting it in the furnace length direction,
At least one or more between the plurality of skids, and a temperature measuring device for measuring a temperature distribution on a lower surface of the metal material;
A temperature calculation unit that calculates a skid mark amount that is a difference between a temperature at a position between the skids of the metal material and a temperature at a position corresponding to the skid of the metal material from a temperature distribution measured by the temperature measuring device. When,
Have
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;
A heating furnace characterized by comprising:   2. The heating furnace control unit for controlling at least one of a conveying speed of the metal material and a furnace temperature in the heating furnace based on a skid mark amount calculated by the temperature calculation unit. The heating furnace described in 1.   2. The apparatus according to claim 1, further comprising a skid mark heating device that locally heats a skid mark at a position corresponding to the skid of the metal material based on the skid mark amount calculated by the temperature calculation unit. Or the heating furnace of 2. 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 furnace according to any one of claims 1 to 3, 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 furnace according to any one of claims 1 to 4, 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 furnace according to claim 5, wherein the temperature known object is arranged at a position where an area occupied in an image captured by the imaging device is 100 pixels or more.   The heating furnace according to any one of claims 1 to 6, wherein the 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 furnace according to any one of claims 1 to 7, 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 furnace according to claim 8, 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 any one of Claims 1-9 characterized by the above-mentioned. Heating furnace.
(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. Position where the angle is not changed (C) Position where the combustion frame is not sandwiched between the metal material A heating method using a heating furnace that heats the metal material while supporting the metal material in the furnace with a plurality of skids and transporting it in the furnace length direction,
A temperature measuring step of measuring a temperature distribution of the lower surface of the metal material by a temperature measuring device disposed at least one between the plurality of skids;
A temperature calculation step for calculating a skid mark amount, which is a difference between a maximum temperature between the skids of the metal material and a minimum temperature at a corresponding position of the skid of the metal material, from the temperature distribution measured in the temperature measurement step. When,
Based on the skid mark amount calculated in the temperature calculation step, a heating control step for controlling at least one of the conveying speed of the metal material and the furnace temperature in the heating furnace,
Have
In the temperature and temperature measurement step,
A temperature known object for correcting stray light in the heating furnace is installed in the vicinity of the luminance measuring unit,
Using the luminance measurement unit, by measuring the radiant energy of the metal material and the temperature known object by monochromatic luminance having a wavelength at which absorption and emission by the furnace gas do not occur,
A heating method, wherein the measured monochromatic luminance is corrected for stray light to obtain a temperature distribution of the metal material.

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