JP7414044B2 - Metal strip temperature measuring method, metal strip temperature measuring device, metal strip manufacturing method, metal strip manufacturing equipment, and metal strip quality control method - Google Patents

Description

The present invention relates to a metal strip temperature measuring method, a metal strip temperature measuring device, a metal strip manufacturing method, metal strip manufacturing equipment, and a metal strip quality control method.

BACKGROUND ART Conventionally, in the manufacturing process of steel strips such as thin steel sheets, temperature control of the steel strip is very important from the viewpoint of building up the material. In particular, in the annealing process, there is a need to measure the temperature of the steel strip during transportation in order to control the temperature of the steel strip to a target temperature in each process. A typical temperature measurement method includes radiation thermometry, which measures the radiance of a steel strip and converts the measured radiance into temperature. However, if the emissivity of the steel strip is not known, it is not possible to accurately measure the temperature, and there are problems in setting the emissivity of steel strips whose surface properties change significantly during the manufacturing process.

Methods that can measure temperature regardless of the emissivity of a metal strip, especially a steel strip include, for example, a method using a temperature measurement device using a multiple reflection type radiation temperature method as disclosed in Patent Document 1, Non-Patent Document 1 There are a method using a temperature measuring device of the temperature measuring roll type as disclosed in Japanese Patent Application Publication No. 2003-20002, and a method using a temperature measuring device equipped with a spectroscopic principal component radiation thermometer as disclosed in Patent Document 2. Can be mentioned. In a method using a multiple reflection radiation temperature measurement device, for example, as shown in FIG. By doing so, the temperature of the steel strip 110 is measured under a pseudo multiple reflection condition and the emissivity approaches 1.0. Furthermore, in a method using a temperature measuring roll type temperature measuring device, for example, as shown in FIG. The temperature of the steel strip 110 is measured by the thermocouple 131 by creating a condition in which the temperature of the roll 130 and the steel strip temperature are the same at a certain portion. Further, in a method using a temperature measuring device equipped with a spectral principal component radiation thermometer, the temperature of the steel strip is measured using the spectral radiation of the steel strip and learning by principal component analysis.

Special Publication No. 4-58568 Patent No. 5979065

Tetsu to Hagane, 1993, vol. 79, No. 7, p. 765-771 Proceedings of the Society of Instrument and Control Engineers, 1982, vol. 18, No. 7, p. 704-709 JIS C 1612, General rules for performance testing of radiation thermometers

The methods disclosed in Patent Document 1 and Non-Patent Document 1 are very effective methods for accurately measuring the temperature of a steel strip. However, it cannot be used unless the temperature of the roll and the steel strip are the same, and the steel strip must be sufficiently wrapped around the roll. The methods disclosed in Patent Document 1 and Non-Patent Document 1 cannot be used in a straight path between two arranged rolls. Furthermore, the method disclosed in Patent Document 2 also requires a contact thermocouple to obtain the true value of the steel strip temperature, making the device large-scale and requiring a large amount of data for learning. There are issues such as:

On the other hand, even in the straight path between rolls, there are processes that are extremely important for temperature control, such as immediately before the steel strip temperature changes suddenly, such as during water quenching, and there is a strong need for temperature measurement. In particular, the temperature of the steel strip immediately before water quenching is extremely important for the quality of the material, but due to equipment constraints, it is difficult to arrange rolls to wrap the steel strip immediately before water quenching. Temperature measurement cannot be applied.

The present invention has been made in view of the above-mentioned problems, and the object thereof is to provide a method for measuring the temperature of a metal band that can easily and accurately measure the temperature of the metal band between two rolls, and a method for measuring the temperature of a metal band between two rolls. An object of the present invention is to provide a measuring device, a method for manufacturing a metal strip, a manufacturing facility for the metal strip, and a quality control method for the metal strip.

In order to solve the above-mentioned problems and achieve the objects, a method for measuring the temperature of a metal strip according to the present invention is provided by measuring the temperature of two rolls around which the metal strip is wound, which are spaced apart from each other in the conveying direction of the metal strip. A method for measuring the temperature of the metal band between the two rolls, the method comprising: measuring the temperature of the metal band between the two rolls, using a thermocouple embedded in an upstream roll located upstream in the conveyance direction of the metal band; measuring the temperature of the upstream roll; measuring the portion of the metal band wrapped around the upstream roll with a first radiation thermometer to obtain radiance; and determining the temperature measured by the thermocouple. calculating the emissivity of the metal strip from the radiance; and calculating the surface temperature of the metal strip at a measurement position set between the two rolls using the emissivity using a second radiation thermometer. The method is characterized by comprising a step of measuring.

Moreover, in the above-mentioned invention, the method for measuring the temperature of a metal band according to the present invention is characterized in that the measurement position of the metal band surface by the first radiation thermometer and the metal band surface measurement position by the second radiation thermometer in the conveyance direction of the metal band are provided. The first radiation thermometer and the second radiation thermometer measure the same location on the metal strip surface using the distance from the measurement position on the strip surface and the conveyance speed of the metal strip or the rotation speed of the upstream roll. It is characterized by being measured by.

Furthermore, the metal strip temperature measuring device according to the present invention measures the surface temperature of the metal strip between two rolls around which the metal strip is wound, which are spaced apart from each other in the conveyance direction of the metal strip. A temperature measuring device for a metal strip, the thermocouple being embedded in an upstream roll located upstream of the two rolls in the conveying direction of the metal strip to measure the temperature of the upstream roll; From the first radiation thermometer that measures the portion of the metal band wrapped around the upstream roll, the temperature measured by the thermocouple, and the radiance obtained from the measurement results of the first radiation thermometer, the The method includes: means for calculating the emissivity of the metal strip; and a second radiation thermometer that uses the emissivity to measure the surface temperature of the metal strip at a measurement position set between the two rolls. It is characterized by:

Further, in the above-described invention, the metal band temperature measuring device according to the present invention is characterized in that the measurement position of the metal band surface by the first radiation thermometer and the metal band surface measurement position by the second radiation thermometer in the conveyance direction of the metal band are provided. The first radiation thermometer and the second radiation thermometer measure the same location on the metal strip surface using the distance from the measurement position on the strip surface and the conveyance speed of the metal strip or the rotation speed of the upstream roll. It is characterized by being measured by.

Further, the method for producing a metal strip according to the present invention includes a step for producing a metal strip, and a temperature measurement step for measuring the temperature of the metal strip produced in the production step by the method for measuring the temperature of a metal strip according to the above-described invention. It is characterized by including the following.

Further, in the method for manufacturing a metal strip according to the present invention, in the above invention, the temperature measuring step measures the temperature of the metal strip during transportation, and the temperature measured in the temperature measuring step is used. The method is characterized in that, among the steps included in the manufacturing step, conditions of one or more steps subsequent to the temperature measurement step are controlled.

Further, the metal strip manufacturing equipment according to the present invention includes a manufacturing equipment for manufacturing a metal belt, a temperature measuring device for a metal belt according to the above invention that measures the temperature of the metal belt manufactured by the manufacturing equipment, The manufacturing equipment is characterized in that it includes a conveyance facility having rolls for conveying the metal strip, and the temperature measuring device is provided within the conveyance facility.

Further, the quality control method for a metal strip according to the present invention includes a temperature measurement step of measuring the temperature of the metal strip using the temperature measurement method for a metal strip according to the above-mentioned invention, and a temperature measurement result obtained by the temperature measurement step. , a quality control step of controlling the quality of the metal strip.

A metal strip temperature measuring method, a metal strip temperature measuring device, a metal strip manufacturing method, a metal strip manufacturing equipment, and a metal strip quality control method according to the present invention measure the temperature of a metal strip between two rolls. This has the effect that measurement can be performed easily and accurately.

FIG. 1 is a diagram showing a schematic configuration of a metal strip temperature measuring device (as an example, a steel strip temperature measuring device) provided in a manufacturing facility for a metal strip (as an example, a steel strip) according to an embodiment. FIG. 2 is a graph showing an example of the calibration results of the first radiation thermometer. FIG. 3 is an explanatory diagram of conventional feedback control. FIG. 4 is an explanatory diagram of feedforward control that can be performed in the steel strip manufacturing equipment according to the embodiment. FIG. 5 is a graph showing the temperature measurement results of the example. FIG. 6 is a diagram showing a schematic configuration of a temperature measurement device using a multiple reflection type radiation temperature method. FIG. 7 is a diagram showing a schematic configuration of a temperature measuring roll type temperature measuring device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a metal strip temperature measuring method, a metal strip temperature measuring device, a metal strip manufacturing method, a metal strip manufacturing facility, and a metal strip quality control method according to the present invention will be described below. Note that this embodiment will be described using a steel strip as an example of the metal strip. That is, the metal strip manufacturing equipment will be explained using a steel strip manufacturing facility as an example, and the temperature measuring device for a metal strip will be explained using a steel strip temperature measuring device as an example. Of course, the present invention is not limited to this embodiment unless the effects of the invention are impaired.

FIG. 1 is a diagram showing a schematic configuration of a steel strip temperature measuring device 1 provided in a steel strip manufacturing facility according to an embodiment.

The steel strip manufacturing facility is equipped with steel strip conveyance equipment described below. As shown in FIG. 1, the conveyance equipment for the steel strip 10 according to the embodiment is provided with a lower conveyance roll 20, an upper conveyance roll 30, and a conveyance roll 80 for changing the conveyance direction of the steel strip 10 up and down. ing. The lower conveyance roll 20 is rotating counterclockwise in FIG. 1, and conveys the steel strip 10 wound around the lower conveyance roll 20 while changing the conveyance direction from sideways to upward. The upper conveyance roll 30 is rotating clockwise in FIG. 1, and is conveyed upward from the lower conveyance roll 20, while changing the conveyance direction of the steel strip 10 wound around the upper conveyance roll 30 downward. . On the downstream side of the upper conveyance roll 30 in the conveyance direction of the steel strip 10, for example, a quenching device 60 for rapidly cooling the steel strip 10 after annealing in an annealing furnace with cooling water is provided. In addition, in the manufacturing equipment for the steel strip 10 according to the embodiment, depending on the type of the steel strip 10 to be manufactured, etc., the quenching device 60 is installed downstream of the upper conveyance roll 30 in the conveyance direction of the steel strip 10. A heating device for heating the steel strip 10 may be provided. Further, on the downstream side of the quenching device 60 in the conveyance direction of the steel strip 10, a conveyance roll 80 around which the steel strip 10 is wound and conveyed is provided. In addition, in this embodiment, the upper conveyance roll 30 and the conveyance roll 80 are two rolls of this invention, Comprising: The upper conveyance roll 30 corresponds to an upstream roll, and the conveyance roll 80 corresponds to a downstream roll.

Here, as can be seen from FIG. 1, immediately before the quenching device 60, there is only a straight path 50 in the vertical direction in which the steel strip 10 after being transported by the upper transport roll 30 is not wrapped around the transport roll. In addition, there is a factor in which the temperature of the steel strip 10 changes due to air cooling or the like during transportation in this straight path 50. Therefore, the manufacturing equipment for the steel strip 10 according to the embodiment includes a steel strip temperature measuring device 1, which is a temperature measuring device for measuring the temperature of the steel strip 10 immediately before the quenching device 60, in the steel strip 10 conveyance facility. We are prepared. The steel strip temperature measuring device 1 includes an upper conveying roll 30 in which a plurality of thermocouples 31 are embedded, a first radiation thermometer 41, a second radiation thermometer 42, a control device 70, and the like.

A plurality of thermocouples 31 are embedded inside the upper conveyance roll 30 along the circumferential direction, and the upper conveyance roll 30 has a function as a temperature measuring roll. In addition, in the steel strip temperature measuring device 1 according to the embodiment, one or more thermocouples 31 may be embedded inside the upper conveyance roll 30. Further, due to the nature of the upper conveying roll 30, the temperature of the upper conveying roll 30, which is heated by heat transfer from the steel strip 10, and the steel strip temperature need to be the same. It is desirable that the band 10 is wrapped around half the circumference or more.

The first radiation thermometer 41 is arranged so as to be able to measure the surface temperature of the portion of the steel strip 10 wound around the upper conveyance roll 30. Note that the measurement position _PA of the first radiation thermometer 41 is not particularly limited as long as it is a portion of the steel strip 10 wrapped around the upper conveyance roll 30. Moreover, in the steel strip temperature measurement device 1 according to the embodiment, one or more first radiation thermometers 41 may be provided to measure the portion of the steel strip 10 wound around the upper conveyance roll 30.

The second radiation thermometer 42 is arranged so as to be able to measure the surface temperature of the steel strip 10 at a position immediately before the quenching device 60 in the conveyance direction of the steel strip 10. Note that the measurement position _PB of the second radiation thermometer 42 is preferably as close to the quenching device 60 as possible. Moreover, in the steel strip temperature measuring device 1 according to the embodiment, one or more second radiation thermometers 42 that measure the surface temperature of the steel strip 10 may be provided at a position immediately before the quenching device 60.

The first radiation thermometer 41 and the second radiation thermometer 42 are arranged at a predetermined distance from the surface of the steel strip so as not to come into contact with the steel strip 10 being transported. At this time, the distance between the first radiation thermometer 41 and the second radiation thermometer 42 and the surface of the steel strip is such that the distance between the first radiation thermometer 41 and the second radiation thermometer 42 is such that the steel strip As long as the target location on the surface is fixed, it is not limited to a specific location. Further, the first radiation thermometer 41 and the second radiation thermometer 42 are not limited to being arranged so as to be able to measure at a position perpendicular to the steel strip surface, as shown in FIG. It may be arranged such that it can be measured at a position inclined within a range of 60[°] or less from a position perpendicular to the upstream side or downstream side in the conveyance direction of the steel strip 10.

The control device 70 calculates the emissivity ε using the measurement results of the first radiation thermometer 41 and the upper conveyance roll 30, applies the calculated emissivity ε when measuring the second radiation thermometer 42, The temperature of the steel strip immediately before the quenching device 60 is calculated. Note that since the emissivity ε has wavelength dependence, it is desirable that the first radiation thermometer 41 and the second radiation thermometer 42 have the same wavelength characteristics.

In addition, in the manufacturing equipment for the steel strip 10 according to the embodiment, the surface properties of the steel strip 10 change as much as possible between the measurement position _PA of the first radiation thermometer 41 and the measurement position P _B of the second radiation thermometer 42. It is preferable not to do so.

Here, in the steel strip temperature measuring device 1 according to the embodiment, the first radiation thermometer 41 has two specifications: one that outputs radiant temperature as a measurement result, and the other that outputs radiance as a measurement result. , both are applicable. Therefore, first, a case will be described in which the first radiation thermometer 41 is designed to output radiation temperature as a measurement result.

The first radiation thermometer 41, which is designed to output radiation temperature, measures the temperature of the steel strip 10 by setting a certain emissivity ε. At this time, any emissivity ε may be set as long as it is known, but for convenience, it is set to 1.0. Then, the portion of the steel strip 10 wrapped around the upper conveyor roll 30 is measured by the first radiation thermometer 41 with the emissivity ε set in this manner, and the radiation temperature T _A of the steel strip 10 is determined by the first radiation thermometer 41. Output as measurement results. At this time, the temperature value measured by the thermocouple 31 of the upper conveyance roll 30 is set as T _r . In order to calculate the emissivity ε of the steel strip 10, it is necessary to compare the radiance when the emissivity ε is 1.0 (blackbody condition) and the actual radiance, so the obtained temperature It is necessary to convert the value into a brightness value. Note that the conversion formula used at this time is calculated in advance by calibration before installing the first radiation thermometer 41. The equation used for calibration may be a general polynomial, but if you are looking for accuracy, use Sakuma Hattori's equation (see Non-Patent Document 2), which is expressed by the following equation (1), which closely approximates Planck's equation. ), etc., and the Sakuma Hattori equation is also used in this embodiment. As a method for calibrating the first radiation thermometer 41, for example, the calibration method disclosed in Non-Patent Document 3 can be applied, and an example of the calibration result of the first radiation thermometer 41 is shown in FIG. As shown in FIG. 2, by calibrating the first radiation thermometer 41, a correlation is obtained between the temperature T and the output signal voltage V output from the first radiation thermometer 41. I understand. At this time, parameters A, B, and C specific to the first radiation thermometer 41 are obtained, and the emissivity ε of the steel strip 10 is calculated using these parameters. In addition, in the following mathematical formula (1), _c2 is the second constant of radiation.

Using the above formula (1), the measured temperature value T _r is converted into the radiance S _r (T _r ), and the result is shown in the following formula (2), and the radiant temperature T _A is converted into the radiance S _A (T _A ). The converted result is shown in the following formula (3). Note that when measuring the radiation temperature _TA with the first radiation thermometer 41, if the emissivity ε is not set to 1.0, the radiation is measured at the emissivity _ε set when measuring the radiation temperature TA. The radiance S _A (T _A ) is corrected by dividing the brightness S _A (T _A ).

Since the emissivity ε is the ratio of the radiance S _r (T _{r ) under the blackbody condition (the result of converting the temperature measurement value T r )} to the actual radiance S _A (T _A ), the following formula is used. It can be calculated using (4).

This time, we used Sakuma Hattori's formula to convert the measured temperature value T _r and radiant temperature T _A to the radiance S _r (T _r ), S _A (T _A ), but the formula used for conversion is The equation is not limited to Sakuma Hattori's equation, but other equations can be used to calculate the relationship between the measured temperature value T _r and the radiant temperature T _A and the radiance S _r (T _r ) and S _A (T _A ). Similar results can be obtained by performing conversion. Which formula to select for converting the measured temperature value T _r and radiation temperature T _A to the radiance S _r (T _r ), S _A (T _A ) depends on the amount of calculation, accuracy, and radiation thermometer. An appropriate formula may be selected in consideration of the wavelength characteristics of .

Next, a case will be described in which the first radiation thermometer 41 is designed to output radiance as a measurement result. In the first radiation thermometer 41 that is designed to output radiance as a measurement result, there is no need to convert the radiant temperature _TA into the radiance S _A ( _TA ) using the above equation (3). Therefore, the radiance S _A (T _A ) which is the output result of the first radiation thermometer 41 is directly substituted into the above formula (4), and the radiance _S The emissivity ε can be calculated by substituting _r (T _r ).

Then, by measuring the temperature of the steel strip 10 with the second radiation thermometer 42 using the calculated emissivity ε, the radiation temperature T _B of the steel strip surface at the measurement position P _B of the second radiation thermometer 42 is determined. can be obtained.

In addition, the second radiation thermometer 42 does not need to be a spot measurement, but can be measured in the width direction of the steel strip surface by applying the emissivity ε calculated using an optical element having a two-dimensional field of view or in the width direction of the steel strip surface. Temperature distribution may also be measured. Further, instead of using an optical element having a field of view in the width direction of the steel strip surface, a spot thermometer may be scanned to measure the width direction temperature distribution of the steel strip surface. At this time, the surface texture and emissivity ε may vary in the width direction of the steel strip surface due to variations in operating conditions in the width direction of the steel strip surface. If one specific emissivity ε is applied when the emissivity ε differs in the width direction of the steel strip surface, there will be a region where the emissivity ε cannot be corrected correctly, leading to an error in the measured temperature. Therefore, it is possible to measure the temperature distribution in the width direction of the steel strip surface by using the first radiation thermometer 41 as an optical element or spot thermometer with a two-dimensional field of view and scanning the first radiation thermometer 41. good. Furthermore, by embedding a plurality of thermocouples in the width direction of the roll, the emissivity distribution in the width direction of the steel strip surface may be calculated from the radiance and thermocouple temperature values at corresponding positions. By calculating the temperature distribution in the width direction of the steel strip surface using the emissivity distribution in the width direction of the steel strip surface, it is possible to calculate the temperature distribution in the width direction of the steel strip surface regardless of all measurement positions, even if there is variation in emissivity ε in the width direction of the steel strip surface. It becomes possible to measure temperature with high accuracy.

Note that in the conveyance direction of the steel strip 10, the measurement position _PA of the first radiation thermometer 41 and the measurement position _PB of the second radiation thermometer 42 are apart. At this time, if a steel strip surface whose surface texture and emissivity ε are significantly different in the conveying direction of the steel strip 10 passes, such as before and after a weld point where two steel strips 10 are welded and connected in the conveying direction, There is a condition in which the emissivity ε is different between the measurement position _PA of the first radiation thermometer 41 and the measurement position _PB of the second radiation thermometer 42. If the emissivity ε calculated by the first radiation thermometer 41 is used under such conditions and the temperature is measured by the second radiation thermometer 42 at the same time, the emissivity ε itself due to the change in the surface properties of the steel strip 10 Since the values are different, this may cause temperature measurement errors. Therefore, the position on the steel strip surface where the temperature is measured at the measurement position _PA of the first radiation thermometer 41 and the position on the steel strip surface where the temperature is measured at the measurement position P _B of the second radiation thermometer 42 are approximately the same. It is preferable to perform alignment so that they are the same. For example, assuming that the conveyance speed of the steel strip 10 is v [m/s], the measurement position P A of the first radiation thermometer 41 and the measurement position P _B of the second radiation thermometer 42 in the conveyance direction of the steel strip _{10 are} Let the distance between the two be L [m]. In this case, at the timing when the same point on the steel strip surface passes the measurement position PA of the first radiation thermometer 41 and the measurement position P _B of the second radiation thermometer 42, the measurement position P _B of the first radiation thermometer 41 is There is a delay of L/v [ _{s] at the measurement position P B of} the second radiation thermometer 42 with respect to the measurement position PA. Therefore, the emissivity ε used to calculate the radiation temperature T _B measured by the second radiation thermometer 42 is equal to the radiation temperature T _A or the radiance S measured by the first radiation thermometer 41 L/v [s] before. The emissivity ε calculated using _A (T _A ) and the temperature value T _r measured by the thermocouple 31 of the upper conveyance roll 30 may be used.

On the other hand, when the distance traveled by the same point on the surface of the steel strip is calculated using the conveyance speed of the steel strip 10 and alignment is performed, the temperature is measured at the measurement position P _A of the first radiation thermometer 41. There is a possibility that a positional shift occurs between the position on the steel strip surface and the position on the steel strip surface where the temperature is measured at the measurement position _PB of the second radiation thermometer 42. The reason for this is that when the conveyance speed of the steel strip 10 is constant, accurate positioning is possible, but the same point on the surface of the steel strip is different from the measurement position P A of the first radiation thermometer 41 to the measurement position P _A of the second radiation thermometer 42. Even if the conveying speed of the steel strip 10 changes before reaching the measurement position _PB , the conveying speed of the steel strip 10 and This is to calculate the distance traveled by the same point on the steel strip surface by multiplying by time. Therefore, if you want to control it more precisely, consider changes in the conveyance speed of the steel strip 10 and integrate the conveyance speed of the steel strip 10 over time to calculate the distance traveled by the same point on the surface of the steel strip. , the position on the steel strip surface where the temperature is measured at the measurement position _PA of the first radiation thermometer 41 and the position on the steel strip surface where the temperature is measured at the measurement position P _B of the second radiation thermometer 42 are approximately the same. It is more preferable to align so that Furthermore, when the position on the steel strip surface is tracked by the rotation speed of the upper conveyance roll 30, the same location on the steel strip surface is measured by the first radiation thermometer 41 and the second radiation thermometer 42. _As shown in _FIG . It is also possible to perform alignment with the position and directly calculate the distance traveled by the same point on the surface of the steel strip. In this way, the position on the steel strip surface measured at the measurement position _PA of the first radiation thermometer 41 and the position on the steel strip surface measured at the measurement position P _B of the second radiation thermometer 42 are aligned. By performing this, it is possible to correct the emissivity ε for the same location on the steel strip surface, without being affected by emissivity fluctuations on the steel strip surface that may occur in the conveying direction of the steel strip 10. , it becomes possible to measure temperature with high accuracy.

Further, in this embodiment, the second radiation thermometer 42 is arranged downstream in the conveyance direction of the steel strip 10 with respect to the first radiation thermometer 41 and the upper conveyance roll 30, but the first radiation thermometer Even if the second radiation thermometer 42 is placed upstream of the steel strip 10 and the upper conveyance roll 30 in the conveyance direction of the steel strip 10, similar temperature measurement is possible. However, in this case, the emissivity ε used by the second radiation thermometer 42 is obtained when the same point on the surface of the steel strip 10 whose temperature is measured by the second radiation thermometer 42 is the first This is after passing the measurement position _PA of the radiation thermometer 41. Therefore, for example, in the second radiation thermometer 42, the temperature is measured using a temporary emissivity ε, or the radiance is acquired, and the emissivity ε obtained later is used to obtain the correct temperature measurement result. Convert.

Furthermore, even when the second radiation thermometer 42 is placed upstream of the first radiation thermometer 41 and the upper conveyance roll 30 in the conveyance direction of the steel strip 10, the same effect can be applied to the surface of the steel strip as described above. It is desirable to align the measurement position _PA of the first radiation thermometer 41 and the measurement position _PB of the second radiation thermometer 42 with respect to the steel strip surface.

Here, in conventional steel strip manufacturing equipment, as shown in FIG. The control device 170 performs feedback control to feed back the difference from the target temperature of the steel strip 10 to the output of the quenching device 160 (for example, the amount of liquid injected toward the steel strip 10 per unit time). The temperature of the band 10 is controlled. However, in feedback control, the output of the quenching device 160 is adjusted by the control device 170 after actually measuring the temperature of the steel strip 10 after quenching, so the responsiveness inevitably decreases compared to feedforward control. Therefore, when manufacturing steel strips with different manufacturing conditions such as temperature and thickness, the responsiveness decreases before and after the manufacturing conditions change, which leads to an increase in temperature failure areas in the steel strip after quenching, resulting in a reduction in yield. decrease.

Therefore, in the manufacturing equipment for the steel strip 10 according to the embodiment, as shown in FIG. ], the control device 70 uses heat transfer calculation to predict the temperature change at the same point on the surface of the steel strip whose temperature was measured by the first radiation thermometer 41 until it reaches the quenching device 60. Then, based on the predicted temperature change, the control device 70 performs feedforward control to adjust the output of the quenching device 60 (for example, the amount of liquid injected toward the steel strip 10 per unit time), and 10 temperature controls are carried out.

In order to improve the responsiveness of temperature control of the steel strip 10, feedforward control based on temperature prediction is effective, but in high temperature ranges such as those in the steel strip manufacturing process, heat transfer is calculated using the following formula (5). Radiation was dominant, as expressed by , and emissivity ε was particularly important.

Therefore, as in the steel strip temperature measuring device 1 according to the embodiment, by estimating the emissivity ε with high accuracy, the accuracy of the heat transfer model is improved, and by introducing feedforward control, the steel strip temperature measurement device 1 can be The temperature of the band 10 can be controlled. Further, the feedforward control and the feedback control may be combined to control the temperature of the steel strip 10 to achieve more accurate temperature control.

Next, examples showing the effects of the invention will be described. In this embodiment, the arrangement of each component constituting the steel strip temperature measuring device 1, such as the first radiation thermometer 41, the second radiation thermometer 42, and the upper conveyance roll 30, is the same as that in FIG. 1. Furthermore, in this embodiment, the first radiation thermometer 41 and the second radiation thermometer 42 are equipped with InGaAs elements. In this embodiment, immediately after the measurement position _PB of the second radiation thermometer 42, there is a water quenching step in which the steel strip 10 is water quenched by a quenching device 60, and the temperature of the steel strip 10 immediately before quenching is Management is extremely important.

In this example, first, the first radiation thermometer 41 was calibrated in advance. Next, the emissivity ε of the steel strip 10 was calculated from the measurement results of the first radiation thermometer 41 and the upper conveyance roll 30. Note that the conversion formula used in calculating the emissivity ε was the formula of Hattori Sakuma. Further, in this embodiment, the measurement position _PA of the first radiation thermometer 41 and the measurement position _PB of the second radiation thermometer 42 are separated by 30 [m] in the conveyance direction of the steel strip 10. Therefore, in this embodiment, the conveyance speed v [m/s] of the steel strip 10 is acquired from the rotation speed of the upper conveyance roll 30, etc., and the first radiation thermometer 41 measures the conveyance speed v [m/s] before 30/v [s]. The emissivity ε calculated using the radiant temperature T _A or the radiant brightness S _A (T _A ) and the temperature value T _r measured by the thermocouple 31 of the upper conveyance roll 30 is calculated using the emissivity ε of the second radiation thermometer 42. This was applied when calculating the radiant temperature _TB . FIG. 5 shows the temperature measurement results of the steel strip 10 of this example.

Here, when the emissivity ε was kept constant, the temperature measurement results of the steel strip 10 by the second radiation thermometer 42 varied widely. On the other hand, in this embodiment, the temperature of the steel strip 10 is measured by the second radiation thermometer 42 by calculating the emissivity ε every moment and constantly correcting the fluctuations in the emissivity ε. 5, it can be seen that the variation in temperature measurement results of the steel strip 10 is reduced. In this way, in this embodiment, the temperature of the steel strip 10 can be easily and accurately measured by the second radiation thermometer 42 using the correct emissivity ε on the straight path 50 immediately before the quenching device 60. .

Furthermore, the present invention may be applied as a temperature measuring device constituting metal strip manufacturing equipment, and the temperature of a metal strip manufactured by known or existing manufacturing equipment may be measured using the temperature measuring device according to the present invention. good. In this case, as already explained, the manufacturing equipment for manufacturing the metal strip includes a conveyance facility having rolls for conveying the metal strip. The temperature measuring device according to the present invention will be installed within this transport facility. Furthermore, the temperature measuring device according to the present invention is most preferably installed between two rolls that transport the metal strip within this transport facility.

Further, the present invention may be applied as a temperature measurement step included in a method for manufacturing a metal strip, and the temperature of the metal strip may be measured in a known or existing manufacturing step. In this case, as already explained, it is desirable to provide a temperature measurement step in the middle of a known or existing manufacturing step in which the temperature of the metal strip being manufactured is measured using the temperature measurement method according to the present invention.

Specifically, it is desirable to provide a temperature measurement step before and after a sudden change in temperature during the manufacturing process of the metal strip. In the manufacturing process of metal strips, rapid cooling using water cooling or air cooling, rapid heating using induction heating furnaces (abbreviated as IH heating furnaces), and direct-fired furnaces are extremely important methods for building the desired material. Accurate temperature measurement before and after temperature changes greatly contributes to the quality of the product material. However, immediately before or after such rapid cooling equipment, or immediately before or after rapid heating equipment, it is often between rolls, and it is difficult to apply highly accurate temperature measurement methods such as multiple reflection type or temperature measuring roll. Have difficulty. By measuring the temperature according to the present invention, it is possible to precisely measure the temperature before and after rapid cooling and rapid heating, thereby making it possible to manufacture a metal strip of the desired material with high precision.

In addition, when feedforward control is used to increase the responsiveness of temperature control, reduce the transient response period, and minimize the temperature unsteady region, the temperature measurement step may be performed in addition to the above metal strip manufacturing method. shall measure the temperature of the metal strip during transportation, and use the temperature measured in the temperature measurement step to perform one or more steps subsequent to the temperature measurement step among the steps included in the manufacturing step. Control process conditions.

Some specific examples of feedforward control will be described using steel strip manufacturing technology as an example. In a heating zone where heating is controlled from the entrance temperature of the steel strip to the target temperature using a radiant heater, due to some change in operating conditions from a steady state, the entrance temperature and the emissivity of the steel strip change, causing the temperature after heating to change. Consider changing from the target temperature. At this time, since the emissivity is equal to the absorption rate, the amount of heat absorbed from the radiant heater depends on the emissivity. In the case of feedback control using the measured temperature value after heating, the output of the radiant heater does not change until it reaches the temperature after heating, and control starts only after it reaches the temperature after heating. The error becomes larger. Using the emissivity calculated by the present invention, the amount of heat absorbed from the radiant heater is simulated at the input side, the temperature after heating is predicted, and the output of the radiant heater is controlled in advance by feedforward. The steel strip temperature can be brought close to the target temperature, and as a result, the area of defective materials can be reduced.

Next, in the heating zone where heating is controlled from the entrance temperature of the steel strip to the target temperature using an IH heating furnace, etc., the entrance temperature and the emissivity of the steel strip change due to some change in operating conditions from the steady state. Consider that the temperature after heating changes from the target temperature. At this time, there is radiant heat removed from the steel strip, but the amount of heat removed depends on the emissivity. In the case of feedback control using the measured temperature value after heating, the output of the IH heating furnace, etc. does not change until the temperature value is reached after heating, and control starts only after reaching the temperature value after heating. The error from temperature increases. Using the emissivity calculated by the present invention, the amount of radiation heat extracted from the steel strip is simulated at the time of entry, the temperature after heating is predicted, and the output of the IH heating furnace is controlled in advance by forward forward control. The subsequent steel strip temperature can be brought closer to the target temperature, and as a result, it is possible to reduce the area of defective materials. In this specific example, fluctuations in the amount of heat removed due to changes in emissivity during heating by IH are predicted, but it is also possible to perform feedforward control of heat removed during air cooling and heat retention in the same way.

According to such metal strip manufacturing equipment and metal strip manufacturing method, metal strips can be manufactured with high yield. In particular, when the metal strip is a steel strip, that is, in the case of steel strip manufacturing equipment and steel strip manufacturing method, the advantage of feedforward control can be maximized, so it is particularly preferable.

Furthermore, the present invention may be applied to a method for controlling the quality of a metal strip, and the quality of the metal strip may be controlled by measuring the temperature of the metal strip. That is, the temperature history of the metal strip during the manufacturing process greatly affects the surface quality and material quality of the final product. Therefore, it is very important for quality control to control the temperature to a predetermined value in each manufacturing process. Specifically, in the present invention, the temperature of the metal strip is measured in the temperature measurement step, and the quality of the metal strip can be controlled from the measurement results obtained in the temperature measurement step. In the next quality control step, based on the measurement results obtained in the temperature measurement step, it is determined whether the temperature measured in each step satisfies pre-specified temperature control standards for the manufactured metal strip, Control the quality of metal strips. According to such a metal strip quality control method, a high quality metal strip can be provided. It is particularly preferable when the metal strip is a steel strip, that is, in the case of a quality control method for steel strips.

1 Steel strip temperature measurement device 10, 110 Steel strip 20 Lower conveyance roll 30 Upper conveyance roll (upstream roll)
31,131 Thermocouple 41 First radiation thermometer 42 Second radiation thermometer 50 Straight path 60,160 Rapid cooling device 70,170 Control device 80 Conveyance roll (downstream roll)
120,130 Roll 140,142 Radiation thermometer

Claims (8)

A method for measuring the temperature of a metal band, the method comprising: measuring the temperature of the metal band in a straight line between two rolls around which the metal band is wound, which are spaced apart in the conveying direction of the metal band ;
Of the two rolls, measuring the temperature of the upstream roll with a thermocouple embedded in the upstream roll located on the upstream side in the conveyance direction of the metal strip;
The metal band is wrapped around the upstream roll for more than half a circumference, and a step of measuring the portion of the metal band wrapped around the upstream roll with a first radiation thermometer to obtain radiance;
calculating the emissivity of the metal band from the temperature measured by the thermocouple and the radiance;
measuring the surface temperature of the metal strip at a measurement position set between the two rolls with a second radiation thermometer using the emissivity;
has
Between the two rolls, there is only the straight path in which no other roll is wrapped around the metal strip,
A method for measuring the temperature of a metal band characterized by the following. a distance between a measurement position of the metal band surface by the first radiation thermometer and a measurement position of the metal band surface by the second radiation thermometer in the conveyance direction of the metal band;
the conveyance speed of the metal band or the rotation speed of the upstream roll;
Using,
2. The method for measuring the temperature of a metal strip according to claim 1, wherein the same location on the surface of the metal strip is measured by the first radiation thermometer and the second radiation thermometer. A metal band temperature measuring device that measures the surface temperature of the metal band in a straight path between two rolls around which the metal band is wound, which are arranged at intervals in the conveying direction of the metal band,
Between the two rolls , there is only the straight path in which no other roll is wrapped around the metal strip,
a thermocouple embedded in an upstream roll located upstream in the conveyance direction of the metal strip among the two rolls, and measuring the temperature of the upstream roll;
a first radiation thermometer in which the metal band is wrapped around the upstream roll for more than half a circumference, and a first radiation thermometer that measures a portion of the metal band wrapped around the upstream roll;
means for calculating the emissivity of the metal band from the temperature measured by the thermocouple and the radiance obtained from the measurement result of the first radiation thermometer;
a second radiation thermometer that measures the surface temperature of the metal strip at a measurement position set between the two rolls using the emissivity;
A metal band temperature measuring device comprising: a distance between a measurement position of the metal band surface by the first radiation thermometer and a measurement position of the metal band surface by the second radiation thermometer in the conveyance direction of the metal band;
the conveyance speed of the metal band or the rotation speed of the upstream roll;
Using,
4. The temperature measuring device for a metal strip according to claim 3, wherein the first radiation thermometer and the second radiation thermometer measure the same location on the surface of the metal strip. manufacturing steps of the metal strip;
A temperature measuring step of measuring the temperature of the metal band in the manufacturing step by the method for measuring the temperature of the metal band according to claim 1 or 2;
A method for manufacturing a metal strip, comprising: The temperature measuring step measures the temperature of the metal band during transportation,
6. The temperature measured in the temperature measuring step is used to control the conditions of one or more steps subsequent to the temperature measuring step among the steps included in the manufacturing step. A method of manufacturing metal strips. manufacturing equipment for manufacturing metal strips;
The metal strip temperature measuring device according to claim 3 or 4, which measures the temperature of the metal strip manufactured by the manufacturing equipment;
Equipped with
The manufacturing equipment includes transport equipment having rolls that transport the metal strip,
A manufacturing facility for metal strips, wherein the temperature measuring device is provided within the conveying facility. A temperature measuring step of measuring the temperature of the metal band by the metal band temperature measurement method according to claim 1 or 2;
a quality control step of controlling the quality of the metal strip from the temperature measurement results obtained in the temperature measurement step;
A method for quality control of a metal strip, comprising:

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