JP4950711B2 - Temperature distribution measuring device for hot rolled material in the plate width direction - Google Patents

Description

  The present invention relates to a plate width direction temperature distribution measuring device for measuring a temperature distribution of a hot rolled material.

  For example, in the process of manufacturing a thin steel plate product by hot rolling, the temperature of both ends of the material to be rolled to be rolled by a finish rolling mill is lower than that of the central portion. Due to the difference in temperature, the rolled material has edge extension and poor flatness. Moreover, since the edge part of the rolling roll of the rolling mill is hardened due to the temperature difference in the sheet width direction of the rolled material, the roll wear of the contact part is more intense than the central part, the roll life is shortened, and the frequency of roll replacement Will increase. For this reason, an edge heater is installed on the entrance side of the finish rolling mill, and the temperature drop is compensated by heating both ends of the plate width.

  In order to heat the both ends of the plate width where the temperature is lowered with an edge heater and raise the temperature accurately, it is necessary to measure an accurate temperature distribution in the plate width direction.

  Further, when manufacturing a thick steel plate product by hot rolling, quality determination such as strength of the rolled material is often performed using a temperature measurement value of the rolled material. For example, in the production of a pressed steel sheet, water cooling is performed immediately after hot finish rolling, and then the temperature of the rolled material is measured. If the measured value is within an allowable range, it is determined that the quality is good. In the manufacture of thick steel plates, not only the plate longitudinal direction but also the plate width direction is subject to quality control, and therefore it is necessary to accurately measure the temperature distribution in the plate width direction (see, for example, Patent Document 1).

  In order to measure the temperature distribution in the plate width direction, a rotating mirror type scanning radiation thermometer is used. That is, the line scan is repeatedly performed in the width direction of the rolled material by the rotation of the mirror, and the temperature distribution pattern in the width direction is repeatedly measured in the longitudinal direction of the plate along with the movement of the rolled material. The distribution state can be known. The temperature distribution data in the plate width direction measured by this thermometer shows a waveform that rises and falls gently in the vicinity of both ends of the plate width, as schematically shown in FIG. For this reason, a threshold temperature value for defining both ends of the plate width is set, and the position of the temperature data matching the threshold temperature value at each of the rising and falling portions of the temperature distribution data is defined as the plate width end portion. Generally, the temperature data between the both ends of the plate width determined in this way is generally recognized as the temperature distribution in the plate width direction.

  However, in temperature measurement with a scanning radiation thermometer, it is affected by radiant heat from the rolled material, reflected heat from the roll, etc., so a sudden temperature change at the end of the plate width, that is, a portion where there is no rolled material Cannot sufficiently follow the rise of the temperature from the plate end to the end of the plate and the fall of the temperature from the plate end to the portion where no rolled material exists, resulting in a response delay. For this reason, as schematically shown in FIG. 15, the measurement temperature deviates from the actual temperature of the rolled material at the end of the sheet width, resulting in a measurement error. As shown in the figure, at the falling edge of the temperature, the temperature of the rolled material decreases from the high temperature of the rolled material to the ambient temperature. This side does not deviate so much from the actual temperature and remains a relatively small measurement error, but at the rising edge of the temperature, it takes a long time to reach the hot rolled material temperature from the low ambient temperature. In the vicinity of the end of the sheet width, the measured temperature greatly deviates from the actual rolled material temperature, resulting in a very large measurement error.

  Therefore, in the temperature measurement with a conventional scanning radiation thermometer, the position of the plate width end and its temperature vary greatly depending on the setting of the threshold temperature value. There was a problem that could not be measured.

  Therefore, as means for solving the above problems, a temperature detector for measuring the temperature distribution in the width direction of the hot-rolled material, a lower light source type CCD camera for measuring the width of the rolled material, and a scanning temperature detector The width direction temperature distribution of the hot rolled material comprising a signal processing device for calculating and processing the rolled material width direction temperature distribution signal inputted from the CCD and the rolled material plate width value signal inputted from the CCD camera in correspondence with the width direction distance of the rolled material A measuring device is disclosed (see Patent Document 2).

  By combining the temperature detector of the rolled material and the edge position detection mechanism using a CCD camera, the temperature distribution in the width direction of the rolled material can be detected with higher accuracy and accuracy than the conventional measurement method using only the scanning radiation thermometer. It is said.

However, using this measuring apparatus, even if the positions of both ends of the plate width can be accurately specified by the CCD camera, the temperature distribution data itself measured by the scanning radiation thermometer as described above, Since data having a measurement error due to a response delay in the vicinity of the portion (particularly the temperature rising portion) is inevitably included, there is still a problem that the temperature at the end of the plate width cannot be measured with high accuracy.
JP 2006-177779 A JP 59-29805

  SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature measuring device that can measure a temperature distribution in the sheet width direction of a rolled material easily and with high accuracy while utilizing a conventional scanning radiation thermometer.

  As a result of diligent research, the present inventors have found that the position of the end of the plate width can be accurately identified by simple data processing using only the temperature distribution data from the scanning radiation thermometer, and completed the following invention. It came to do.

The invention according to claim 1 is a temperature distribution measuring means for measuring the temperature distribution in the sheet width direction of the hot rolled material by scanning two scanning radiation thermometers in the opposite directions, and each of the scanning radiation temperatures. From the temperature distribution data measured in the plate width direction, the position of the inflection point at the temperature falling part (hereinafter referred to as “inflection point position”) and the temperature gradient at this inflection point (hereinafter referred to as “inflection point temperature gradient”). Inflection point information calculation means for calculating)) and a large number of plate width direction temperature distribution data having the same inflection point temperature gradient are extracted from a large number of plate width direction temperature distribution data measured in the past in advance. The temperature variation at each position of the temperature falling part is calculated from a large number of plate width direction temperature distribution data having almost the same inflection point temperature gradient to obtain the plate width direction distribution of the temperature variation. Based on the distribution of variation in the plate width direction Estimate the width end position, by inflection point temperature gradient operation for estimating the plate width edge positions is repeated a number for the case where different, the inflection point position and inflection point temperature gradient and the plate width edge position The inflection point information versus end position relationship recording means for recording the relationship, the inflection point position and the inflection point temperature gradient calculated by the inflection point information calculation means, Inflection point information vs. end position positional relationship Using the relationship recorded in the recording means, a plate width end position determining means for determining the plate width end position, and the plate width end position determining means for determining the plate width end position A sheet width direction temperature distribution data creating means for synthesizing two sheet width direction temperature distribution data determined in position and creating one sheet width direction temperature distribution data; It is a board width direction temperature distribution measuring apparatus of a hot rolled material.

  According to the present invention, after using the temperature data at the falling portion of the temperature distribution data respectively measured by the two scanning radiation thermometers, after accurately determining the positions of both ends of the plate width by simple data processing, By combining the two temperature distribution data, it is possible to easily and accurately measure the plate width temperature distribution.

Embodiment
The configuration of the plate width direction temperature distribution measuring apparatus according to the present invention is shown in the block diagram of FIG. As shown in the figure, the plate width direction temperature distribution measuring device according to the present invention includes (1) temperature distribution measuring means, (2) inflection point information calculating means, and (3) inflection point information versus end position relationship. Recording means, (4) plate width end position determining means, and (5) plate width direction temperature distribution data creating means. Hereinafter, each component will be sequentially described.

(1) Temperature distribution measuring means In this means, two scanning radiation thermometers are scanned in opposite directions to measure the temperature distribution in the plate width direction of the hot rolled material. As the scanning radiation thermometer, a rotating mirror type generally used for measuring the temperature distribution in the sheet width direction of the hot rolled material may be used. Two scanning radiation thermometers 2, 2 are arranged side by side in the plate width direction above the rolled material 1, for example, as shown in FIG. What is necessary is just to set so that it may scan in a mutually reverse direction.

  In this way, two scanning radiation thermometers were used, and both were configured to scan in opposite directions from the central portion of the plate width toward the end portion. By eliminating the temperature distribution data of the part that has a large measurement error due to the response delay, and specifying the plate width end position using only the temperature distribution data of the temperature falling part with a relatively small measurement error, as will be described later. This is to increase the measurement accuracy.

(2) Inflection point information calculation means By this means, the position of the inflection point at the temperature falling portion (hereinafter referred to as “inflection point position”) is obtained from the temperature distribution data in the plate width direction measured by each scanning radiation thermometer. And a temperature gradient at the inflection point (hereinafter referred to as “inflection point temperature gradient”). Hereinafter, the inflection point position and the inflection point temperature gradient are collectively referred to as “inflection point information”.

  That is, as described above, since the measurement error due to the response delay is very large at the temperature rising portion, only the temperature distribution data at the temperature falling portion with a relatively small measurement error is used without using the temperature distribution data at the temperature rising portion. use.

  Then, the position of the inflection point of the temperature distribution curve at the temperature falling portion is determined by performing numerical differentiation on the temperature distribution data of the temperature falling portion sampled and digitized at regular intervals, and the inflection point is further determined. Calculate the slope of the tangent at the point. Specifically, for example, the position of the inflection point and the gradient of the tangent may be calculated as follows.

  That is, in the plate width direction temperature distribution data schematically shown in FIG. 3, the temperature data value at the point a corresponding to an arbitrary measurement position in the plate width direction is f (a), and the tangent gradient is f ′ (a ), F ′ (a) = f (a + 1) −f (a). Further, it is defined as f ″ (a) = f ′ (a) −f ′ (a−1). Then, the point a is shifted one by one in the direction of the plate width end portion from the plate width central portion side to f ″. As the value of (a) is calculated, a point where the value of f ″ (a) changes from negative to positive is searched. This positively changed point is an inflection point, and this point is set as X. In addition, the gradient of the tangent at the point X, which is the inflection point, is f ′ (X) = f (X + 1) −f (X).

(3) Inflection point information versus edge position relationship recording means By using this means, a number of plate width direction temperature distribution data measured in the past in advance, the plate width direction temperature distribution having substantially the same inflection point temperature gradient. For each data, the temperature variation at each position of the temperature falling part is calculated to obtain the plate width direction distribution of the temperature variation, and the plate width end position is estimated based on the plate width direction distribution of the temperature variation. The relationship between the inflection point information (inflection point position and inflection point temperature gradient) and the plate width end position is obtained, and this relationship is recorded in a table, for example. Hereinafter, a more detailed description will be given using specific examples.

  That is, first, from a large number of past temperature distribution data measured with a scanning radiation thermometer, a large number of temperature distribution data in which the waveform of the rolling material temperature in the central portion of the sheet width and the waveform of the temperature falling portion are substantially equal are extracted and collected. . FIG. 4 shows a superposition of these many temperature distribution data. Next, a temperature variation (standard deviation) at each position of the temperature falling portion is calculated from the large number of temperature distribution data to obtain a plate width direction distribution of the temperature variation. FIG. 5 shows the distribution of the obtained temperature variation in the plate width direction.

  From FIG. 4, it is presumed that the plate width end position exists at any measurement position between 10 and 18 around the high temperature side of the temperature falling part. Further, from FIG. 5, the temperature variation from the measurement position (any measurement position between the measurement positions 10 to 18) estimated to have the plate width end to the measurement position 22 which is the inflection point position. It can be seen that (standard deviation) is monotonically increasing. That is, it is assumed that the temperature variation (standard deviation) increases monotonously at the measurement position where no rolled material exists.

  Next, a large number of temperature distribution data having different temperatures at the central portion of the sheet width, but different in the waveform of the temperature falling portion, are extracted and collected. The temperature variation (standard deviation value) at each position is calculated to obtain the plate width direction distribution of the temperature variation. FIG. 6 shows these temperature distribution data superimposed on each other, and FIG. 7 shows the distribution of temperature variations in the plate width direction.

  Unlike the case of FIG. 5, the temperature variation shown in FIG. 7 rapidly rises on the side near the center of the plate width of the temperature falling portion to show a maximum value, and then gradually decreases to show a minimum value. Thereafter, it increases monotonously as in the case of FIG. In this way, the temperature variation rapidly increases on the side near the center of the plate width at the temperature falling part, for example, when water droplets remaining in the vicinity of the end of the plate width when water is cooled on the surface of the rolled material. It is assumed that the amount fluctuates. Therefore, it is estimated that at least the rolled material is present up to the measurement position 16 where the influence of temperature variation remains. On the other hand, as discussed above with reference to FIG. 5, the temperature variation (standard deviation) is assumed to increase monotonously at the measurement position where there is no rolled material. It is presumed that no rolled material exists from the measurement position 17 at which measurement starts to the measurement position 21 that is the inflection point position. Therefore, from these, it can be estimated that the plate width end position corresponds to the measurement position 16 indicated by the point A in FIG.

  Therefore, when the inflection point position and the inflection point temperature gradient are obtained for each temperature distribution data of the large number of temperature distribution data shown in FIG. 6, the inflection point position is collected at the measurement position 21 for any temperature distribution data. It was found that the inflection point temperature gradient is concentrated in the range of −50 ° C. or more and less than −40 ° C. From these results, when the inflection point temperature gradient of the temperature distribution data is in the range of −50 ° C. or more and less than −40 ° C., the plate width end position is measured from the inflection point position (measurement position 21 in this example). It can be estimated that it corresponds to the measurement position (measurement position 16 in this example) returned to the center of the plate width by 5 positions.

  8 to 11 are examples in the case where the inflection point temperature gradient is different from those in FIGS. 4 to 7, and from these results, the inflection point temperature gradient of the temperature distribution data is −40 ° C. or more and less than −30 ° C. In this range, the end position of the plate width is the measurement position (measurement position 17 in this example) that is returned to the center of the plate width by 4 measurement positions from the inflection point position (measurement position 21 in this example). It can be estimated that it corresponds.

By repeating the same operation as described above many times when the inflection point temperature gradient is different, the inflection point information (inflection point position and inflection point temperature gradient) of the temperature distribution data as illustrated in Table 1 below, and Since a relationship with the plate width end position is required, this relationship may be recorded in a predetermined storage area of the arithmetic unit.

  Depending on the installation height of the radiation thermometer from the rolled material, the scanning speed, etc., the degree of influence and response delay due to the radiant heat from the rolled material and the reflected heat from the roll, etc. change, and the temperature distribution data changes. Therefore, the relationship between the inflection point information (the inflection point position and the inflection point temperature gradient) of the temperature distribution data and the plate width end position does not necessarily match the results shown in Table 1 above.

(4) Plate width end position determining means By this means, the inflection point information (inflection point position and inflection point temperature gradient) calculated by the inflection point information calculation means and the gradient-to-position relation recording means are recorded. The plate width end position is determined using the recorded relationship (in this example, the relationship shown in Table 1 above).

  For example, when the inflection point position of certain temperature distribution data is the measurement position 21 and the inflection point temperature gradient is −37 ° C., the plate width end position is the inflection point position from the relationship shown in Table 1 above. The measurement position 17 is determined to be returned to the center of the plate width by four measurement positions from the measurement position 21.

(5) Plate width direction temperature distribution data creation means In this means, two plate width direction temperature distribution data whose plate width end portion position is determined by the plate width end position determination means are combined into one Create plate width direction temperature distribution data.

  When synthesizing the temperature distribution data, there is usually an instrumental difference between the two radiation thermometers. Therefore, as schematically shown in FIG. Occurs. For this reason, for example, in order to match the temperature data of the overlapping part of the two plate width direction temperature distribution data (that is, the temperature data at the same measurement position), the other one with the one plate width direction temperature distribution data as the reference What is necessary is just to synthesize | combine, after correcting only the plate | board width direction temperature distribution data only for a device difference.

  The temperature distribution data in the plate width direction created in this way uses only the temperature data of the temperature falling part with relatively little measurement error due to response delay, and the positions of both ends of the plate width are accurate by simple data processing. Accordingly, the temperature at the end of the plate width is estimated with high accuracy, and the measurement of the plate width temperature distribution can be realized easily and with high accuracy.

(Modification)
In the above-described embodiment, the example in which the two scanning radiation thermometers 2 and 2 are arranged side by side in the plate width direction has been shown. However, as shown in FIG. Also in this case, it is necessary to set so as to scan in opposite directions, as is apparent from the measurement principle of the present invention described above.

It is a block diagram which shows the structure of the board width direction temperature distribution measuring apparatus which concerns on embodiment. It is a perspective view which shows the example of arrangement | positioning (example arrange | positioned in the board width direction) of the two scanning radiation thermometers which concern on embodiment. It is a graph for demonstrating the calculation method which calculates | requires the inflection point position and inflection point temperature gradient in a temperature falling part from board width direction temperature distribution data. It is the graph which superimposed and displayed many temperature distribution data in which the waveform of a rolling-material temperature in a sheet | seat width center part and the waveform of a temperature falling part are substantially equal. It is a graph which shows the board width direction distribution of the temperature dispersion | variation in the temperature falling part obtained from many temperature distribution data shown in FIG. It is the graph which superimposed and displayed many temperature distribution data from which the rolled material temperature in a plate | board width center part is substantially equal, but the waveform of a temperature falling part differs. It is a graph which shows the board width direction distribution of the temperature dispersion | variation in the temperature falling part obtained from many temperature distribution data shown in FIG. FIG. 5 is a graph in which a large number of temperature distribution data is superimposed and displayed, in which the inflection point temperature gradient is different from that of FIG. 4 and the rolled material temperature in the central portion of the sheet width is substantially equal to the waveform of the temperature falling portion. It is a graph which shows the board width direction distribution of the temperature dispersion | variation in the temperature falling part obtained from many temperature distribution data shown in FIG. FIG. 7 is a graph in which a large number of temperature distribution data is superimposed and displayed, in which the inflection point temperature gradient is different and the rolled material temperature in the central portion of the sheet width is substantially equal, but the waveform of the temperature falling portion is different. It is a graph which shows the board width direction distribution of the temperature dispersion | variation in the temperature falling part obtained from many temperature distribution data shown in FIG. It is a schematic diagram for demonstrating the synthetic | combination method of two board width direction temperature distribution data. It is a perspective view which shows another example of arrangement | positioning (example arrange | positioned in a plate longitudinal direction) of the two scanning radiation thermometers which concern on embodiment. It is a schematic diagram for demonstrating the method of determining the board width edge part position from the board width direction temperature distribution data measured with the conventional scanning radiation thermometer. It is a schematic diagram for demonstrating the difference between the temperature distribution data measured with the scanning radiation thermometer and the actual rolling material temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rolled material 2 ... Scanning type radiation thermometer

Claims (1)

Temperature distribution measuring means for scanning two scanning radiation thermometers in opposite directions to measure the temperature distribution in the sheet width direction of the hot rolled material;
From the temperature distribution data in the plate width direction measured by each scanning radiation thermometer, the position of the inflection point at the temperature falling portion (hereinafter referred to as “inflection point position”) and the temperature gradient at the inflection point (hereinafter referred to as “inflection point position”). Inflection point information calculation means for calculating "inflection point temperature gradient"),
In advance, a large number of plate width direction temperature distribution data having substantially the same inflection point temperature gradient are extracted and collected from a large number of plate width direction temperature distribution data measured in the past. The temperature variation at each position of the temperature falling part is calculated from the temperature distribution data in the plate width direction to obtain the plate width direction distribution of the temperature variation, and the plate width end position is determined based on the plate width direction distribution of the temperature variation. Estimate and repeat the operation of estimating the plate width end position many times when the inflection point temperature gradient is different , to obtain the inflection point position and the relationship between the inflection point temperature gradient and the plate width end position, Inflection point information to record this relationship versus end position relationship recording means,
The inflection point position and the inflection point temperature gradient calculated by the inflection point information calculation means and the relationship recorded in the inflection point information versus end position relationship recording means, Plate width end position determining means for determining the position;
The plate width direction temperature distribution data is created by synthesizing two plate width direction temperature distribution data whose plate width end position is determined by the plate width end position determining means to create one plate width direction temperature distribution data. Means,
An apparatus for measuring a temperature distribution in the plate width direction of a hot-rolled material.

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