JP5907127B2 - Temperature measuring method and temperature measuring device - Google Patents

Description

  The present invention relates to a temperature measuring method and a temperature measuring device for measuring a surface temperature distribution of a slab during continuous casting in a continuous casting machine.

  In the continuous casting process, the surface temperature distribution of the slab during continuous casting is an important monitoring item for quality control, and measurement of the temperature distribution over the entire surface of the slab surface is required. As a method for measuring the surface temperature of a high-temperature object, a contact-type method in which a thermocouple or the like is brought into contact with the surface of the object and radiation energy (infrared rays) radiated from the object using a radiation thermometer or the like Two types are mainly known, a non-contact method that is performed by detecting. Of these, the contact-type method is difficult to apply when the object moves like a slab during continuous casting. For this reason, conventionally, measurement of the surface temperature of a slab is generally performed using a radiation thermometer.

  A thermography is mentioned as a typical radiation thermometer. Thermography can measure a two-dimensional temperature distribution easily and continuously. However, when such a radiation thermometer is used to measure the temperature of the slab surface, the cooling water used to cool the slab during the continuous casting process becomes mist (water smoke) and the optical path of the radiation thermometer. The cooling water adheres to the surface of the slab and forms a water paste, causing scattering and absorption of infrared rays, thereby reducing the measurement accuracy of the surface temperature.

  In order to solve this kind of problem, various proposals have been made so far. For example, in Patent Document 1, a water column as an optical waveguide is formed between a steel material to be measured and a radiation thermometer, and radiation light from the surface of the steel material to be measured is detected by the radiation thermometer through the water column. Thus, the accuracy of the temperature measurement value is improved by eliminating the influence of water, steam, etc. existing in the measurement visual field of the radiation thermometer by stably securing the optical path of the radiation light from the steel material. In Patent Document 2, a lens for condensing infrared light from a slab is brought closer to the vicinity of the slab through a fiber, and secondary cooling water or steam is injected by injecting a gas toward the slab. The measurement of the surface temperature that eliminates the influence of the is realized.

JP 2008-164626 A JP 2012-071330 A

  However, the technique of Patent Document 1 described above is not suitable for acquiring the temperature distribution on the slab surface because it measures the temperature at one point in the surface of the steel material. On the other hand, in patent document 2, since temperature measurement is performed while scanning a radiation thermometer along the width direction of a slab, it is possible to acquire a temperature distribution over the entire surface of the slab. However, when measuring a moving object like a slab using such a scanning radiation thermometer, if the scanning speed is slow relative to the moving speed of the object, the measurement may be lost. A large-scale facility is required to speed up the operation. Further, in the case of the configuration in which the lens is brought close to the vicinity of the slab as in the technique of Patent Document 2, there is a problem that the lens mistakenly contacts the object and causes a failure of the apparatus.

  This invention is made in view of the above, Comprising: It aims at providing the temperature measuring method and temperature measuring device which can measure the surface temperature distribution of the slab surface whole area from a remote simply and with high precision. To do.

  In order to solve the above-described problems and achieve the object, a temperature measurement method according to the present invention is a temperature measurement method for measuring a surface temperature distribution of a slab during continuous casting in a continuous casting machine, wherein the casting The upper and lower surfaces of the piece are supported by roll segments arranged at a predetermined interval along the conveyance direction of the slab, and the width direction end of the slab is perpendicular to the conveyance direction of the slab. An acquisition step of photographing an interval between predetermined roll segments to be photographed by at least one imaging device installed on the outside and acquiring image data of a surface area of the slab passing through the interval of the photographing object And a conversion step of converting luminance information of the image data into temperature information.

  In the temperature measurement method according to the present invention as set forth in the invention described above, the imaging device is located above the upper surface of the predetermined roll segment on the outside of the widthwise end of the slab, and 80% of the optical path. The above is characterized in that it is installed at a height position defined so as to pass through a position lower than the upper surface of the predetermined roll segment.

  Further, in the temperature measurement method according to the present invention, in the above invention, the imaging device includes a straight line connecting a viewpoint of the imaging device and an upper corner of the slab passing through the interval of the imaging target, and a vertical direction. It is characterized in that it is installed at an installation angle defined so that the angle formed by is not less than 40 degrees and not more than 65 degrees.

  Further, in the temperature measurement method according to the present invention, in the above invention, the imaging device includes two imaging devices arranged opposite to each other on both outer sides of the widthwise end of the slab, and the obtaining step includes The image data of the same surface area of the slab is acquired by each of the two imaging devices, and the conversion step selects the maximum value for each pixel from the luminance information of the same surface area of the slab. And converting into the temperature information.

  In the temperature measurement method according to the present invention as set forth in the invention described above, the detection wavelength of the imaging device is in the range of 0.85 μm to 1.0 μm.

Further, in the temperature measurement method according to the present invention, in the above invention, the acquisition step is performed while blowing gas at a flow rate of 30 m ³ / min or more toward the surface area of the slab passing through the interval of the imaging target. The photographing is performed.

In the temperature measurement method according to the present invention, in the above invention, a cold water pipe for supplying cooling water to the surface of the slab is provided above the roll segment along the conveyance direction of the slab. The acquisition step is characterized in that the imaging is performed while blowing gas at a flow rate of 30 m ³ / min or more toward the piping position of the cold water pipe above the interval of the imaging target.

  In the temperature measurement method according to the present invention as set forth in the invention described above, the conversion step calculates a maximum brightness value in the slab conveying direction as a representative value of each position in the slab width direction from the image data, and the representative value Including the step of setting the luminance information at each position in the slab width direction.

  Further, in the temperature measurement method according to the present invention as set forth in the invention described above, the conversion step is a slab as a representative value of each position in the slab width direction from a plurality of the image data continuously captured within a predetermined time. The method includes a step of calculating a maximum luminance value in the conveyance direction and using the representative value as luminance information at each position in the slab width direction.

  The temperature measuring device according to the present invention is a temperature measuring device for measuring a surface temperature distribution of a slab during continuous casting in a continuous casting machine, and the slab is along a conveying direction of the slab. The upper and lower surfaces are supported by roll segments arranged at a predetermined interval, and at least one image pickup device installed above the outer side in the width direction of the slab perpendicular to the conveying direction of the slab. And an acquisition unit that controls the operation of the imaging apparatus and performs imaging processing of an interval between predetermined roll segments to be imaged, and acquires image data of a surface area of the slab passing through the imaging object interval And conversion means for converting luminance information of the image data into temperature information.

  According to the present invention, since the imaging device can be installed outside the width direction end of the slab perpendicular to the slab conveyance direction, the upper space of the roll segment is removed from the field of view of the imaging device and the object to be photographed. The interval between roll segments can be photographed. Therefore, image data of the surface area of the slab can be acquired while suppressing the influence of mist generated mainly above the roll segment. The luminance information of the acquired image data can be converted into temperature information. According to this, the surface temperature distribution of the entire surface of the slab can be measured remotely and simply with high accuracy.

FIG. 1 is a schematic diagram illustrating a configuration example of a continuous casting machine. Drawing 2 is an explanatory view explaining the composition of the temperature measuring device and roll segment of an embodiment. FIG. 3 is another explanatory diagram illustrating the configuration of the temperature measuring device and the roll segment according to the embodiment. FIG. 4 is a flowchart illustrating a processing procedure of temperature measurement processing performed by the image processing apparatus. FIG. 5 is an explanatory diagram for explaining the principle of extracting luminance information. FIG. 6 is an explanatory diagram for explaining another extraction principle of luminance information. FIG. 7 is a graph showing the correspondence between temperature and luminance. FIG. 8 is a diagram illustrating the relationship between the incident angle and the emissivity of a laser beam irradiated on a general steel material. FIG. 9 is a diagram illustrating the temperature obtained based on the slab surface image data photographed simultaneously by two cameras. FIG. 10 is an explanatory diagram illustrating the configuration of the temperature measurement device according to the first modification. FIG. 11 is an explanatory diagram for explaining the configuration of the temperature measurement device according to the second modification. FIG. 12 is another explanatory diagram illustrating the configuration of the temperature measurement device according to the second modification. FIG. 13 is another explanatory diagram illustrating the configuration of the temperature measurement device according to the third modification. FIG. 14 is a diagram illustrating a temperature measurement result by the temperature measurement device according to the embodiment. FIG. 15 is a diagram illustrating a temperature measurement result by the temperature measurement device of the first modification. FIG. 16 is a diagram illustrating a temperature measurement result by the temperature measurement device of the third modification. FIG. 17 is a diagram illustrating a result of comparison and verification of the temperature measurement result.

  Hereinafter, with reference to drawings, the form for implementing the temperature measuring method and temperature measuring device of this invention is demonstrated. Note that the present invention is not limited to the embodiments. Moreover, in description of drawing, the same code | symbol is attached | subjected and shown to the same part.

(Embodiment)
FIG. 1 is a schematic diagram illustrating a configuration example of a continuous casting machine 1 to which a temperature measuring device 20 (see FIG. 2 and the like) of the present embodiment is applied. First, the configuration of the continuous casting machine 1 will be described. In the continuous casting machine 1 shown in FIG. 1, a mold 4 is provided below a tundish 3 into which molten steel 2 is poured, and an immersion nozzle 5 serving as a molten steel supply port to the mold 4 is provided at the bottom of the tundish 3. Yes. Below the mold 4, a plurality of roll segments 60 (see FIG. 2 and the like) each provided with support rolls 6 a and 6 b are arranged and installed along the conveying direction (drawing direction) of the slab S. The slab S is drawn along the rolls 6a and 6b at a predetermined drawing speed.

  A plurality of divided cooling zones 7a to 15a and 7b to 15b are arranged in the slab conveying direction to constitute a secondary cooling zone. In each of the cooling zones 7a to 15a and 7b to 15b, a plurality of cooling nozzles (not shown) such as nozzles for spraying or air mist spraying are installed, and secondary from the cooling nozzles to the surface of the slab S. The secondary cooling of the target slab S is performed by spraying the cooling water.

  In FIG. 1, among the support rolls 6a and 6b, the support roll 6a is disposed on the side opposite to the reference surface (upper surface side), and the support roll 6b is disposed on the reference surface side (lower surface side). Yes. Similarly, of the cooling zones 7a to 15a and 7b to 15b, those arranged on the side opposite to the reference plane are referred to as cooling zones 7a to 15a, and those arranged on the reference plane side are referred to as cooling zones 7b to 15b. In FIG. 1, the total number of cooling zones constituting the secondary cooling zone is nine, but the number of zones is not limited to this. In an actual continuous casting machine, how many secondary cooling zones are divided (how many zones are used) varies depending on the length of the machine.

  Moreover, in the machine of the continuous casting machine 1, the camera 21 (21-1, 21-2; figure as an imaging device) which comprises the temperature measuring device 20 in the appropriate place in the secondary cooling zone along a slab conveyance direction. 2), and the surface of the slab S on the side opposite to the reference plane is photographed. The obtained image data is used for temperature measurement processing in an image processing device 23 (see FIG. 2 and the like) described later. In FIG. 1, the camera 21 is illustrated between the cooling zone 12a and the cooling zone 13a. However, in reality, the camera 21 is installed at an installation position corresponding to an imaging target described later.

  FIG. 2 shows a configuration of the temperature measuring device 20 of the present embodiment and a roll for supporting a slab S during continuous casting, which is a subject of the cameras 21-1 and 21-2 constituting the temperature measuring device 20. It is explanatory drawing which showed typically the structure of the segment 60 seeing from the slab conveyance direction (drawing direction), and has shown the slab S in the cross section of the width direction. FIG. 3 is a plan view of the periphery of the roll segment 60 including the camera 21 (21-1, 21-2) constituting the temperature measuring device 20, and is the longitudinal direction of the slab S (hereinafter referred to as the slab transport direction). The slab conveying direction is also referred to as “slab longitudinal direction”.) Two of the roll segments 60 arranged along the slab longitudinal direction are illustrated. In the following, the slab longitudinal direction (vertical direction in FIG. 2) is shown as the X direction, the width direction of the slab S as the Y direction, and the direction perpendicular to both the X direction and the Y direction as the Z direction.

  Further, FIG. 2 shows a cooling water pipe (water cooling pipe) 50 that is piped into the continuous casting machine 1. The cooling water pipe 50 supplies cooling water to the cooling nozzle in the secondary cooling zone described above, and a slab is placed above both ends along the width direction of the slab S with a roll segment 60 interposed therebetween. Piped along the transport direction.

  As shown in FIG. 3, the roll segment 60 is installed with a predetermined interval 63 between adjacent roll segments 60. As shown in FIG. 2, each roll segment 60 includes a pair of frame members 61 a and 61 b arranged on the upper surface side that is the anti-reference surface side and the lower surface side that is the reference surface side of the slab S, and a frame member. Each of 61a and 61b is provided with support rolls 6a and 6b that are rotatably held via bearings, and upper and lower support rolls 6a and 6b are arranged to face each other with a predetermined gap (gap) therebetween. The The roll segment 60 supports the slab S by passing the slab S through the gap between the support rolls 6a and 6b, and guides it in the slab transport direction.

  The temperature measuring device 20 includes two cameras 21-1 and 21-2 that photograph the surface (upper surface) of the slab S supported by the roll segment 60 as described above from above, and these cameras 21-1 and 21-21. 2 and an image processing device 23 connected via a cable or the like. The upper part of the slab S is partially opened by the interval 63 between the roll segments 60 described above, and the cameras 21-1 and 21-2 take the interval 63 as an object to be photographed and pass the slab S passing therethrough. The surface area (hereinafter referred to as “inter-segment cast slab area”) A1 is taken from above. In addition, you may select suitably which the space | interval 63 between the roll segments 60 arranged along the slab conveyance direction is taken as the object of photographing. For example, the space between the roll segments 60 is selected according to the position in the secondary cooling zone suitable for measuring the surface temperature of the slab S.

  The cameras 21-1 and 21-2 are disposed opposite to each other across the slab S on both outer sides of the widthwise end of the slab S. It is installed so that the interval 63 between the segments 60 is looked down obliquely. Specifically, the cameras 21-1 and 21-2 are installed on the outer sides of the slab passing path so that the installation positions and the installation angles are the predetermined specified positions and specified angles. -2 is fixed by the tripods 40-1 and 40-2. The installation bases 30-1 and 30-2 may be provided exclusively at appropriate locations in the continuous casting machine 1, or use space on the passage provided for the operator's work outside the slab passage route. It is good.

  Here, the position in the slab longitudinal direction (X direction position), the position in the slab width direction (Y direction position), the height position (Z direction position) of the cameras 21-1 and 21-2 defined in advance, The installation angle will be described.

First, as shown in FIG. 3, the X-direction positions of the cameras 21-1 and 21-2 are defined as the X-direction position of the interval 63 between the roll segments 60 to be photographed. Further, the Y direction positions of the cameras 21-1 and 21-2 are substantially equal to the distances L _Y1 and L _{Y2 in} the Y direction between the viewpoint 211 and the corresponding side end surface of the slab S as shown in FIG. Each is defined as a position in the Y direction as a distance.

The positions of the cameras 21-1 and 21-2 in the Z direction are the upper surfaces of the two roll segments 60 that form the interval 63 to be imaged (outside the width direction end of the slab S). It is defined that 80% or more of the optical path passes through the Z direction position below the upper surface of the roll segment 60 above the Z direction position of the upper surface of the frame member 61a. The ratio of the optical path passing through the Z-direction position below the upper surface of the roll segment 60 can be calculated by the following equation (1). L _Z1 represents the distance between the Z direction position of the viewpoint 211 shown in FIG. 2 and the Z direction position of the slab surface, and L _Z2 represents the distance between the Z direction position of the viewpoint 211 and the Z direction position of the upper surface of the roll segment 60. Represents. In the present embodiment, for example, L _Z1 = 1.8 m and L _Z2 = 0.3 m define the positions of the cameras 21-1 and 21-2 in the Z-axis direction. In this case, the optical path length obtained by the above equation (1) is about 83%.
(L _Z1 -L _Z2 ) / L _Z1 (1)

The installation angles of the cameras 21-1 and 21-2 are indicated by alternate long and short dash lines in FIG. 2 connecting the viewpoint 211 and the upper corner of the slab S that passes through the position in the X direction of the viewpoint 211. An angle θ ₁ formed by a straight line and a vertical direction (a vertical line passing through the above-mentioned nearby upper corner) is not less than 40 degrees and not more than 65 degrees, and passes through the viewpoint 211 and the position of the viewpoint 211 in the X direction. An angle θ ₂ formed by a straight line indicated by a two-dot chain line in FIG. 2 that connects the upper corner portion of the slab S (the far side) and the vertical direction (a vertical line passing through the far upper corner portion) is formed. It is defined on the condition that it is 40 degrees or more and 65 degrees or less. In the present embodiment, for example, θ ₁ = 40 degrees and θ ₂ = 65 degrees define the installation angles of the cameras 21-1 and 21-2.

  The cameras 21-1 and 21-2 whose installation positions and installation angles are defined as described above are for detecting the intensity of radiant energy (infrared rays) radiated from the surface of the slab. This is realized using an image sensor such as a sensor. The detection wavelength used for detection is in the range of 0.85 μm to 1.0 μm. The cameras 21-1 and 21-2 continuously photograph images in the field of view (slab surface image) including the interval 63 between the roll segments 60 to be photographed, and the obtained image data (slab surface) Image data) is output to the image processing device 23.

  The image processing device 23 acquires the slab surface image data by controlling the operations of the cameras 21-1 and 21-2, and performs image processing on the slab surface image data to measure the temperature of the slab surface. (Temperature measurement processing) is performed. The image processing apparatus 23 includes an image data acquisition unit 231 as an acquisition unit, a luminance information extraction unit 233 and a temperature information conversion unit 235 as conversion units as main functional units. The image processing device 23 connects an arithmetic device such as a CPU, a main storage device, an auxiliary storage device such as a hard disk and various storage media, a communication device, an output device such as a display device and a printing device, an input device, and each unit. Alternatively, it can be realized by a known hardware configuration including an interface device for connecting an external input, for example, a general-purpose computer such as a workstation or a personal computer can be used.

  FIG. 4 is a flowchart showing the processing procedure of the temperature measurement process performed by the image processing apparatus 23. In the present embodiment, the cameras 21-1 and 21-2 are installed so that the installation position and the installation angle are the above-described predetermined specified position and specified angle, and the image processing apparatus 23 is shown in FIG. The temperature measurement method is implemented by executing the temperature measurement process.

  As shown in FIG. 4, in the temperature measurement process, the image data acquisition unit 231 controls the operations of the cameras 21-1 and 21-2 during the operation of the continuous casting machine 1 and continuously performs the imaging process. The slab surface image data is acquired (step s1; acquisition step). Specifically, the image data acquisition unit 231 performs the imaging processing of the two cameras 21-1 and 21-2 in synchronization, and acquires the two slab surface image data at one imaging timing. At this time, the image data acquisition unit 231 assigns a shooting sequence number to the obtained slab surface image data sequentially for subsequent processing. The same shooting order number is assigned to two slab surface image data having the same shooting timing. Through the above processing, a series of slab surface image data obtained by continuously capturing the inter-segment slab region A1 passing through the interval 63 between the roll segments 60 to be imaged is obtained. Although only a part of the slab surface can be seen from the interval 63 between the roll segments 60, the slab S passes through the interval 63 in the process of being pulled out along the slab conveying direction. By continuously photographing the inter-segment cast slab region A1, the region corresponding to the entire length and the entire width of the slab surface (the entire slab surface) can be photographed.

  Thereafter, the luminance information extraction unit 233 repeatedly performs the processing of steps s5 and s7 to process the slab surface image data acquired in step s1 by two for each photographing order number. After extracting the information, the temperature information conversion unit 235 converts the luminance information in the entire surface of the slab surface into temperature information (conversion step).

  Here, the principle of extracting luminance information will be described. In order to simplify the description, attention is paid here to a series of slab surface image data photographed by one camera 21. The luminance information extraction unit 233 obtains luminance information of the entire slab by extracting the luminance information of the inter-segment slab region A1 from a series of slab surface image data and sequentially arranging them on the time axis.

  FIG. 5 is an explanatory diagram for explaining the principle of extracting luminance information, and also shows a part of a series of slab surface image data I11 and I12 acquired sequentially with the passage of time. In the individual slab surface image data, an inter-segment slab area A1 is shown at the center as in the slab surface image data I11 shown in FIG. The luminance information extraction unit 233 performs image processing on such a series of slab surface image data in the shooting order (in the order of shooting order numbers), and sets the pixel value of the center inter-segment slab area A1 in the slab width direction. The brightness information (brightness value) of each pixel is extracted with reference to FIG. Since the slab surface image data is captured by the cameras 21-1 and 21-2 whose installation position and installation angle are fixed by the tripods 40-1 and 40-2 as described above, the slab surface image is obtained. The position of the inter-segment cast slab area A1 shown in the data can be specified in advance.

  For example, the luminance information extracting unit 233 performs luminance information D11 of each pixel on the extraction line L1 indicated by a broken line in FIG. 5 from the slab surface image data I11 in the process of performing image processing on a series of slab surface image data in the order of photographing. To extract. Next, the luminance information D12 of each pixel on the same extraction line L1 is extracted from the slab surface image data I12 with the next shooting order number. Then, the luminance information extraction unit 233 arranges the luminance information D11 and D12 extracted from the slab surface image data in this way in the time axis direction in the order of the photographing order numbers. If the same processing is repeated up to the slab surface image data with the last photographing sequence number, luminance information D1 over the entire surface of the slab surface is extracted.

  FIG. 6 is an explanatory diagram for explaining another extraction principle of luminance information. As shown in FIG. 6, the luminance information extraction unit 233 replaces the pixel values of the pixels on the extraction line L1 of the slab surface image data I11 and I12 as the luminance information D11 and D12 as described above. The maximum brightness value in the slab conveyance direction in the inter-segment slab area A1 of the slab surface image data I11 and I12 may be used as the brightness information D11 and D12. That is, the luminance information extraction unit 233 calculates the maximum luminance value in the slab conveyance direction in the inter-segment slab region A1 as a representative value of each position in the slab width direction of each slab surface image data I11 and I12. A set of calculated maximum luminance values (representative values) at each position in the slab width direction is set as luminance information D11 and D12. In other words, the brightness information extraction unit 233 uses the slab surface image data including the maximum brightness value in the slab transport direction in the slab S imaged from the interval 63 of the segment roll 60 from each slab surface image data I11 and I12. And the luminance information D11 and D12 of each pixel on the extraction line L1 is extracted from the slab surface image data of the calculated maximum luminance value.

  As one of the factors that reduce the accuracy of temperature measurement, there is water that is generated when cooling water adheres to the surface of the slab S. At the location where the water paste adheres, this water paste absorbs infrared rays and reduces the accuracy of temperature measurement. According to the method shown in FIG. 6, even if water glue is attached on the slab S, if this water glue is smaller than the interval 63 of the segment roll 60, the slab conveyance direction in which no water glue is attached. Since the luminance value at the position is reflected, the influence of water is reduced.

  Further, the water on the slab S is heated by the high-temperature slab S, and the side in contact with the slab S boils to form a vapor film. Since the water paste is present on the vapor film, it has a high fluidity, and it has been confirmed that it tends to deviate from the field of view in about 1-2 seconds. Therefore, the luminance information extraction unit 233 applies the method shown in FIG. 6 and transfers the slab from a plurality of slab surface image data I11 and I12 that are continuously photographed within a predetermined time of about 1 to 3 seconds. The slab surface image data composed of the maximum brightness value in the direction is calculated, and the slab surface image data I11 and I12 are replaced with the slab surface image data having the maximum brightness value, and the brightness information of each pixel on the extraction line L1 is calculated. D11 and D12 are extracted. Thereby, it is possible to easily eliminate the influence of almost all water without changing the configuration of the temperature measuring device 20.

  As an actual process, as shown in FIG. 4, the luminance information extraction unit 233 first sets a shooting order number to be processed (step s3). When step s3 is performed first, the first shooting order number is set as an initial value. Subsequently, the luminance information extraction unit 233 extracts an extraction line L1 that traverses the inter-segment slab area A1 along the slab width direction from each of the two slab surface image data to which the imaging order numbers to be processed are assigned. Luminance information of each upper pixel is extracted (step s5). Then, the luminance information extraction unit 233 compares the luminance information extracted from the two slab surface image data for each pixel at the same position, and selects the larger one (maximum value) as luminance information for each pixel. (Step s7).

  Then, the luminance information extraction unit 233 determines whether or not the processing in steps s5 and s7 has been performed on all shooting order numbers as processing targets. If processing has not been performed up to the last shooting order number (step s9: No), the luminance information extraction unit 233 returns to step s3, moves the processing target to the next shooting order number, and then performs steps s5 and s7. Process. On the other hand, when the process is performed up to the last shooting order number (step s9: Yes), the process proceeds to step s11.

  In step s11, the temperature information conversion unit 235 converts the luminance information selected in step s7 into temperature information. The conversion from the luminance information to the temperature information performed here is performed according to a correspondence relationship between temperature and luminance set in advance. The correspondence between temperature and luminance is set by measuring the luminance corresponding to the temperature using, for example, a black body furnace.

FIG. 7 is a graph showing the relationship between temperature and luminance measured using a black body furnace as described above, with the horizontal axis representing temperature and the vertical axis representing luminance. The relationship between the temperature and the brightness shown in FIG. 7 is expressed by the following simplified formula (2). In the following equation (2), T is temperature, X is luminance, and A and B are predetermined constants. The temperature information conversion unit 235 calculates the corresponding temperature information by sequentially substituting the luminance information in the entire area of the slab surface selected in step s7 into the following equation (2), so that the temperature information in the entire area of the slab surface is calculated. That is, the surface temperature distribution over the entire slab surface is measured.
T = A × Ln (X) + B (2)

  As described above, in the present embodiment, the surface temperature distribution of the entire slab surface is measured using the slab surface image data captured by the cameras 21-1, 21-2, but the accuracy of this temperature measurement is reduced. Another factor to be caused is mist existing above the gap 63 between the roll segments 60. As a result of verifying the occurrence of mist around the roll segment 60, the inventors of the present invention have found that most of the mist is generated in the vicinity of the cooling water pipe 50 piped above the roll segment 60. I confirmed.

  Here, the mist is formed by very small water droplets in the air when water vapor is cooled or saturated, and is similar to a cloud or fog. The reason why many mists are generated in the vicinity of the cooling water pipe 50 is considered as follows. That is, first, the cooling water sprayed on the surface of the slab in order to cool the slab S is evaporated by the heat of the slab S. Since the water vapor generated thereby is present in the vicinity of the slab S at this time, the high temperature state is maintained by the heat of the slab S. Therefore, the generated water vapor gradually moves upward. Here, even if it is away from the vicinity of the slab S, the space below the upper surface of the roll segment 60 is a narrow space and its temperature is maintained at a relatively high temperature. And move on. And if it moves further upwards and leaves | separates from the space | interval 63 between the roll segments 60 upwards rather than the upper surface of the roll segment 60, water vapor | steam will change to mist with the fall of ambient temperature. In the upper space on the upper surface of the roll segment 60, the temperature is particularly low in the vicinity of the cooling water pipe 50, and it is considered that mist is easily formed.

  In order to deal with such a problem, in the present embodiment, the cameras 21-1 and 21-2 are opposed to each other on both outer sides of the width direction end portion of the slab S, and the width direction end portions of the slab S are respectively disposed. The interval 63 between the roll segments 60 to be imaged is set so as to be looked down obliquely from above the outside. Here, since the cooling water pipe 50 is arranged along the slab conveying direction above both side ends of the slab S with the roll segment 60 interposed therebetween, the width direction of the slab S as described above. If the cameras 21-1 and 21-2 are installed so that the interval 63 between the roll segments 60 to be photographed is obliquely looked down from the upper outside of the end portion, the periphery of the cooling water pipe 50 around which the water vapor is likely to be mist as described above. The interval 63 between the roll segments 60 to be photographed can be photographed outside the field of view range. Therefore, it is possible to photograph the inter-segment cast slab area A1 while suppressing the influence of the mist described above.

  However, in some cases, the mist generated as described above drifts above the interval 63 between the roll segments 60 to be imaged to block the optical paths of the cameras 21-1 and 21-2. Causes infrared scattering and reduces the accuracy of temperature measurement.

  In order to cope with such a problem, in the present embodiment, most of the optical paths of the cameras 21-1 and 21-2, specifically, 80% or more of the optical paths are positioned in the Z direction below the upper surface of the roll segment 60. The positions of the cameras 21-1, 21-2 in the Z direction are defined so as to pass, and the optical path of the cameras 21-1, 21-2 passing above the upper surface of the roll segment 60 where a lot of mist exists is less than 20% of the whole. It was decided to. According to this, it becomes possible to image | photograph the segment slab area | region A1, suppressing the above-mentioned influence of mist.

  The mist described above does not exist uniformly above the interval 63 between the roll segments 60. Therefore, even if the optical path of one camera 21 is blocked by mist, the optical path of the other camera 21 is not necessarily affected by this mist. Actually, it has been confirmed that the mist tends to exist on one side end side of the slab S under the influence of the external environment such as wind generated in the continuous casting machine 1 and the temperature inside the machine.

  In order to cope with such a problem, in the present embodiment, the slab surface image data is synchronized with the photographing timing by the two cameras 21-1 and 21-2 arranged to face each other across the slab S passage route. Decided to get. Then, luminance information on the extraction line L1 that traverses the inter-segment slab region A1 along the slab width direction is extracted from each of the two slab surface image data obtained at the same photographing timing, and each pixel is extracted. The maximum value (the larger value) was selected and converted to temperature information. Therefore, it is possible to select and use the luminance information with less influence of mist and water from the luminance information on the extraction line L1 extracted from the two slab surface image data, and measure the surface temperature distribution.

Further, when the installation angles of the cameras 21-1, 21-2, that is, θ ₁ and θ ₂ shown in FIG. ₂ are large, there arises a problem that the emissivity is lowered. This is because when θ ₁ and θ ₂ are increased, the influence of the surface roughness of the slab S is reduced and the reflectance is increased. For an object such as the slab S that does not transmit, reflectance + radiation. Since the relationship of rate = 1 is established, when θ ₁ and θ ₂ are increased, the reflectance is increased and the emissivity is lowered. Although the specific values of θ ₁ and θ ₂ vary depending on the substance, in general, the emissivity is not significantly decreased in the range of 0 to 60 degrees, and the values within a certain range can be maintained. Are known.

FIG. 8 is a diagram illustrating the relationship between the incident angle and the emissivity using the relationship between the reflectance and emissivity of laser light irradiated on a general steel material. The reflectivity was calculated by measuring the total reflected light of the laser beam, and the emissivity was obtained from the relationship of emissivity = 1−reflectance. As shown in FIG. 8, if the incident angle is 60 degrees or less, a decrease in emissivity can be suppressed to 0.003. From this, it can be seen that if θ ₁ and θ ₂ are 60 degrees or less, temperature measurement can be performed with high accuracy. Moreover, if the incident angle is 65 degrees or less, the emissivity decrease is suppressed to 0.01 or less. From this, it can be seen that if θ ₁ and θ ₂ are 65 degrees or less, temperature measurement can be performed with sufficient accuracy.

The inventors of the present invention further verify the relationship between θ ₁ , θ ₂ and the decrease in emissivity in the case of the slab S, and if θ ₁ , θ ₂ is within the range of 40 degrees to 65 degrees, radiation is performed. It was found that the effect of the rate drop on temperature measurement can be tolerated. In this embodiment, θ ₁ = 40 degrees and θ ₂ = 65 degrees are used to define the installation angles of the cameras 21-1 and 21-2. According to this, the fall of emissivity can be prevented and temperature measurement can be performed accurately.

  FIG. 9 is a diagram illustrating the temperature obtained based on the slab surface image data taken at the same timing by the two cameras 21-1 and 21-2. The angle formed by the camera 21-1 and the vertical direction of the slab S changes from 65 degrees to 40 degrees as the position in the slab width direction changes from left to right (from a negative value to a positive value). To do. The angle formed by the camera 21-2 and the vertical direction of the slab S changes from 40 degrees to 65 degrees as the position in the slab width direction changes from left to right. As shown in FIG. 9, the temperature calculated | required based on each slab surface image data image | photographed with these two cameras 21-1 and 21-2 is substantially in agreement. From this, in this Embodiment, it turns out that an emissivity does not fall in the range of 40 degree | times-65 degree | times, but temperature measurement can be performed accurately.

  Further, in the present embodiment, the inter-segment slab region in which the influence of the above-mentioned water is reduced by setting the detection wavelengths of the cameras 21-1 and 21-2 within the range of 0.85 μm to 1.0 μm. A1 shooting can be realized.

  As described above, according to the present embodiment, the cameras 21-1 and 21-2 are installed at a pre-set installation angle at a pre-set installation location, and between the roll segments 60 to be photographed. The inter-slab slab region A1 passing through the interval 63 can be photographed. And the surface temperature distribution of the slab surface whole area | region can be measured by converting brightness | luminance information into temperature information using the obtained slab surface image data. According to this, the slab surface image data while suppressing the influence of the scattering and absorption of infrared rays by the gap 63 between the roll segments 60 to be imaged and the mist existing above the roll segment 60 or the water adhering to the slab surface. And the luminance information of the inter-segment cast slab region A1 can be converted into temperature information. Therefore, the surface temperature distribution over the entire surface of the slab can be measured remotely and simply with high accuracy.

  In the above-described embodiment, the two cameras 21-1 and 21-2 are installed at a predetermined specified position and specified angle. Of these two cameras 21-1 and 21-2, It is also possible to configure a temperature measuring device with only one of these cameras and measure the surface temperature distribution over the entire surface of the slab surface using the slab surface image data captured by this single camera.

(Modification 1)
FIG. 10 is an explanatory diagram for explaining the configuration of the temperature measurement device 20A in the first modification, and schematically shows the configuration of the temperature measurement device 20A and the roll segment 60 as seen from the slab conveying direction, similarly to FIG. Yes. In the first modification, the same reference numerals are given to the same configurations as those in the above-described embodiment.

As shown in FIG. 10, the temperature measurement device 20 </ b> A of the first modification includes blowers 25 </ b> A- 1 and 25 </ b> A- 2 installed on the installation bases 30-1 and 30-2 of the cameras 21-1 and 21-2. . Each of the blowers 25A-1 and 25A-2 supplies air dried at a flow rate of 30 m ³ / min or more toward the cooling water pipe 50 on the same side end side of the slab S. Further, the image processing apparatus 23A according to the first modification includes an image data acquisition unit 231, a luminance information extraction unit 233, a temperature information conversion unit 235, and a side blower control unit 237A.

  The temperature measurement apparatus 20A of the first modification is similar to the temperature measurement apparatus 20A in the procedure of the temperature measurement method illustrated in FIG. 4 described in the above embodiment while the image data acquisition unit 231 performs the photographing process of step s1. The direction blower control unit 237A performs control to drive the blowers 25A-1 and 25A-2.

  The inventors of the present invention further verified the occurrence of mist around the roll segment 60 described above, and as a result, a part of the mist generated in the vicinity of the cooling water pipe 50 above the roll segment 60 is spaced between the roll segments 60. It was confirmed that it was flowing into 63. According to the first modification, the mist generated in the vicinity of the cooling water pipe 50 above the roll segment 60 is blown from the blowers 25A-1 and 25A-2 so that the mist does not flow into the interval 63 between the roll segments 60 to be photographed. The inter-segment cast slab area A1 can be photographed while forcibly blowing off with the supplied air. According to this, it is possible to efficiently suppress the influence of the interval 63 between the roll segments 60 to be imaged and the presence of mist on the roll segment 60 on the temperature measurement. Moreover, it is only necessary to install the blowers 25A-1 and 25A-2 on the installation bases 30-1 and 30-2 of the cameras 21-1 and 21-2, and a complicated configuration is not required. Therefore, it is possible to measure the surface temperature distribution over the entire surface of the slab easily and more accurately from a remote location.

(Modification 2)
FIG. 11 is an explanatory diagram for explaining the configuration of the temperature measurement device 20B in the second modification, and schematically shows the configuration of the temperature measurement device 20B and the roll segment 60 as seen from the slab conveying direction, similarly to FIG. Yes. FIG. 12 is a plan view of the roll segment 60 including the cameras 21-1 and 21-2 constituting the temperature measuring device 20B. In the second modification, the same reference numerals are assigned to the same components as those in the above-described embodiment.

As shown in FIGS. 11 and 12, the temperature measuring device 20 </ b> B according to Modification 2 includes two blowers 27 </ b> B installed above a space 63 between roll segments 60 to be photographed by the cameras 21-1 and 21-2. -1,27B-2. These two blowers 27B-1 and 27B-2 are fixed above the interval 63 between the roll segments 60, for example, by being fixed to a structure (not shown) constituting the continuous casting machine 1. Each of the blowers 27B-1 and 27B-2 supplies air dried at an air volume of 30 m ³ / min or more toward the interval 63 between the roll segments 60. Note that the number of blowers to be installed is not limited to two, and may be one or three or more. Further, the image processing device 23B of Modification 2 includes an image data acquisition unit 231, a luminance information extraction unit 233, a temperature information conversion unit 235, and an upper blower control unit 239B.

  The temperature measuring device 20B according to the second modified example has an upper portion while the image data acquiring unit 231 executes the photographing process of step s1 in the procedure of the temperature measuring method described with reference to FIG. 4 in the above embodiment. The blower control unit 239B performs control to drive the blowers 27B-1 and 27B-2.

  According to the second modification, the inter-segment slab region A1 can be photographed while forcibly removing the water adhering to the slab surface with the air supplied from the blowers 27B-1 and 27B-2. According to this, the influence which the presence of the water paste on the slab surface has on the temperature measurement can be efficiently suppressed. Further, it is only necessary to install the blowers 27B-1 and 27B-2 above the interval 63 between the roll segments 60 to be photographed, and a complicated configuration is not required. Therefore, it is possible to measure the surface temperature distribution over the entire surface of the slab easily and more accurately from a remote location.

(Modification 3)
FIG. 13 is an explanatory diagram for explaining the configuration of the temperature measurement device 20C in the third modification, and schematically shows the configuration of the temperature measurement device 20C and the roll segment 60 as seen from the slab conveying direction, as in FIG. Yes. In the third modification, the same reference numerals are given to the same components as those in the above-described embodiment.

  As illustrated in FIG. 13, the temperature measurement device 20 </ b> C according to the third modification includes the blowers 25 </ b> A- 1 and 25 </ b> A- on the installation bases 30-1 and 30-2 of the cameras 21-1 and 21-2 described in the first modification. 2 and the blowers 27B-1 and 27B-2 above the interval 63 between the roll segments 60 to be photographed by the cameras 21-1 and 21-2 described in the second modification. Further, the image processing device 23B of Modification 2 includes an image data acquisition unit 231, a luminance information extraction unit 233, a temperature information conversion unit 235, a side blower control unit 237A, and an upper blower control unit 239B.

  The temperature measurement device 20C according to the third modification is similar to the temperature measurement device 20C in the procedure of the temperature measurement method illustrated in FIG. 4 described in the above embodiment while the image data acquisition unit 231 performs the photographing process of step s1. The side blower control unit 237A performs control to drive the blowers 25A-1 and 25A-2, and the upper blower control unit 239B performs control to drive the blowers 27B-1 and 27B-2.

  According to the third modification, the mist generated near the cooling water pipe 50 above the roll segment 60 is blown from the blowers 25A-1 and 25A-2 so that the mist does not flow into the interval 63 between the roll segments 60 to be photographed. The inter-slab slab area A1 is photographed while forcibly blowing off by the supplied air and additionally removing the water adhering to the slab surface by the air supplied from the blowers 27B-1 and 27B-2. can do. According to this, it is possible to efficiently suppress the influence on the temperature measurement due to the presence of the mist above the interval 63 between the roll segments 60 to be imaged and the presence of mist on the slab surface. Also, the blowers 25A-1 and 25A-2 are installed on the installation bases 30-1 and 30-2 of the cameras 21-1 and 21-2, and the blower 27B- is disposed above the interval 63 between the roll segments 60 to be photographed. It is only necessary to install 1 and 27B-2, and a complicated configuration is not required. Therefore, the surface temperature distribution over the entire slab surface can be measured from a remote location easily and with higher accuracy.

  Actually, the temperature measurement device 20 of the above embodiment, the temperature measurement device 20A of the first modification example, and the temperature measurement device 20C of the third modification example are separately configured, and the interval 63 between the same roll segments 60 was photographed as a photographing object. The surface temperature distribution on the surface of the slab surface was measured based on the slab surface image data, and at the same time, the occurrence of mist and the adhesion of water glue during photographing were confirmed visually. FIG. 14 is a diagram showing a temperature measurement result by the temperature measuring device 20 of the above embodiment, in which the horizontal direction is the slab width direction, the vertical direction is the slab longitudinal direction, the slab width direction is 2 m, and the slab length The surface temperature distribution measured about the object range in the slab surface whose hand direction is 1 m is shown. 15 is a diagram showing a temperature measurement result by the temperature measurement device 20A of the first modification, and FIG. 13 is a diagram showing a temperature measurement result by the temperature measurement device 20C of the third modification, and FIG. The surface temperature distribution of the target range within the slab surface of the same size is shown.

  Moreover, the temperature measurement result by the temperature measurement apparatus 20 of the said embodiment shown in FIGS. 14-16, the temperature measurement apparatus 20A of the modification 1, and the temperature measurement apparatus 20C of the modification 3 was compared and verified. FIG. 17 is a diagram showing the verification results, and a temperature change curve L51 in which the surface temperature distribution along the slab longitudinal direction on the line L2 indicated by the broken line in FIG. 14 is graphed is indicated by a two-dot chain line. A temperature change curve L52 in which the surface temperature distribution on the line L3 indicated by a broken line in the graph is graphed is indicated by a one-dot chain line, and a temperature change curve L53 in which the surface temperature distribution on the line L4 indicated by a broken line in FIG. Is shown. The positions within the slab surface where the surface temperature distributions indicated by the temperature change curves L51 to L53 are not the same, and thus the temperatures themselves do not match, but the measurement accuracy can be compared. In addition, in FIG. 17, each surface temperature distribution is shown by making the upper end of each line L2-L4 of FIGS. 14-16 into a base point (distance = 0), and the distance along a slab longitudinal direction from a base point as a horizontal axis. ing.

  First, according to the temperature measurement device 20 of the above-described embodiment, as shown in the temperature change curve L51 of FIGS. 14 and 17, temperature measurement is performed in almost the entire range although some portions where the temperature is not measured are seen. It was found that temperature measurement can be realized while suppressing the influence of the presence of mist and water on temperature measurement. However, the temperature is greatly reduced locally at the portions P511, P513 and the like surrounded by a broken line in FIG. 17, and with reference to FIG. 14, the portions including these portions P511, P513 cover the entire area in the slab width direction. There are some places where the temperature drops. Actually, when the position in the target slab width direction within the target range is imaged, the occurrence of mist is confirmed at the interval 63 between the roll segments 60 to be imaged and above, and infrared rays are scattered by this mist. It is thought that the brightness value decreased and the measured temperature decreased.

  On the other hand, according to the temperature measuring device 20A of the first modified example, as shown in the temperature change curve L52 of FIG. 15 and FIG. 17, the temperature is changed as indicated by the portions P511 and P513 in FIG. It has been found that temperature measurement can be realized without effectively reducing the effect of mist, compared to the temperature measurement device 20 of the above embodiment. However, the temperature is finely reduced in the parts P521, P523 and the like surrounded by a broken line in FIG. 17, and referring to FIG. 15, the temperature is lowered in a relatively small range in addition to these parts P521, P523. A place can be seen. Actually, adhesion of water glue has been confirmed at the relevant position within the target range, and the brightness value decreased due to the absorption of infrared rays by the liquid phase (water) that forms the water glue, and the measured temperature was considered to have decreased. It is done.

  On the other hand, according to the temperature measuring device 20C of the third modification, as shown in the temperature change curve L53 in FIG. 16 and FIG. 17, the temperature is increased as indicated by the portions P511 and P513 in FIG. The temperature measurement can be realized without greatly decreasing the temperature due to the presence of water or water, unlike the portions P521 and P523 in FIG. Thus, according to the modification 3, it turned out that temperature measurement can be performed with higher accuracy than the temperature measurement device 20A of the modification 1.

DESCRIPTION OF SYMBOLS 1 Continuous casting machine 60 Roll segment 6a, 6b Support roll 50 Cooling water pipe 20, 20A, 20B, 20C Temperature measuring device 21-1, 21-2 Camera 25A-1, 25A-2, 27B-1, 27B-2 Blower 23, 23A, 23B, 23C Image processing device 231 Image data acquisition unit 233 Luminance information extraction unit 235 Temperature information conversion unit 237A Side blower control unit 239B Upper blower control unit S Slab

Claims (9)

A temperature measurement method for measuring the surface temperature distribution of a slab during continuous casting in a continuous casting machine,
The slab has upper and lower surfaces supported by roll segments arranged at a predetermined interval along the conveying direction of the slab,
The interval between predetermined roll segments to be imaged is photographed by two imaging devices arranged opposite to each other on both sides outside the widthwise end of the slab perpendicular to the conveyance direction of the slab, Obtaining the image data of the surface area of the slab passing through the interval;
Converting the luminance information of the image data into temperature information ,
The obtaining step obtains image data of the same surface area of the slab by each of the two imaging devices,
The said conversion step selects and uses the maximum value for every pixel from the luminance information of the same surface area | region of the said slab, and converts it into the said temperature information, The temperature measuring method characterized by the above-mentioned .   The imaging device is located above the upper surface of the predetermined roll segment on the outside of the widthwise end of the slab, and 80% or more of the optical path passes through a position lower than the upper surface of the predetermined roll segment. The temperature measuring method according to claim 1, wherein the temperature measuring method is installed at a specified height position.   The imaging device is defined such that an angle formed by a straight line connecting a viewpoint of the imaging device and an upper corner portion of the slab passing through the interval of the imaging target and a vertical direction is not less than 40 degrees and not more than 65 degrees. The temperature measurement method according to claim 1, wherein the temperature measurement method is installed at a set installation angle. Temperature measuring method according to any one of claims 1-3, wherein the detection wavelength of the imaging device is in the range of 0.85Myuemu～1.0Myuemu. The acquisition step, according to claim 1-4, characterized in that performing the imaging while blowing gas at a set air volume level of more than 30 m ³ / min toward the surface region of the slab passing through the interval between the imaging target The temperature measurement method according to any one of the above. Above the roll segment, a cold water pipe for supplying cooling water to the surface of the slab is provided along the conveying direction of the slab,
The obtaining step, any claim 1-5, characterized in that performing the imaging while blowing gas at a set air volume level of more than 30 m ³ / min toward the pipe position in the cold water pipe in the interval above the imaging target The temperature measuring method as described in any one. The converting step calculates a maximum luminance value in the slab conveying direction as a representative value of each position in the slab width direction from the image data, and sets the representative value as luminance information of each position in the slab width direction. temperature measuring method according to any one of claims 1-6, characterized in that it comprises. The conversion step calculates a maximum brightness value in the slab conveyance direction as a representative value of each position in the slab width direction from a plurality of the image data continuously captured within a predetermined time, and the representative value is calculated by casting. temperature measuring method according to any one of claims 1-7, characterized in that it comprises the step of the brightness information of each position in the strip width direction. A temperature measuring device for measuring the surface temperature distribution of a slab during continuous casting in a continuous casting machine,
The slab has upper and lower surfaces supported by roll segments arranged at a predetermined interval along the conveying direction of the slab,
Two imaging devices disposed opposite to each other on both outer sides of the widthwise end of the slab perpendicular to the slab conveyance direction;
An acquisition unit that controls the operation of the imaging device to perform imaging processing of an interval between predetermined roll segments to be imaged, and acquires image data of a surface area of the slab that passes through the interval of the imaging object;
Conversion means for converting luminance information of the image data into temperature information ,
The acquisition means acquires image data of the same surface area of the slab by each of the two imaging devices,
The said conversion means selects and uses the maximum value for every pixel from the luminance information of the same surface area | region of the said slab, and converts it into the said temperature information, The temperature measuring device characterized by the above-mentioned .