JP2015147216A - temperature distribution prediction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature distribution prediction device capable of accurately predicting the temperature distribution in the plate width direction, of a material to be rolled.SOLUTION: The temperature distribution prediction device includes: central temperature measurement means 17 for measuring the surface temperature of a width-direction central part of a material to be rolled; and width directional temperature measurement means 20 for measuring the surface temperature of an optional width-direction point of the material to be rolled. The temperature distribution prediction device further includes: central temperature calculation means 18 for calculating the surface temperature of the width-direction central part of the material to be rolled; and width directional temperature calculation means for calculating the surface temperature of the optional width-direction point of the material to be rolled passing through a third position based on a measured value of a first position by the central temperature measurement means 17, a measured value of a second position by the central temperature calculation means 18 and a calculated value of the second position and a third position by the central temperature calculation means 18. Further, the third position is a position downstream of the first position and upstream of the second position.

Description

  The present invention relates to a temperature distribution prediction apparatus used in a rolling line.

  In recent years, specifications required by customers for products have become stricter. In particular, regarding rolled products, it is important to keep mechanical properties such as strength and ductility within an allowable range in addition to dimensions and shapes.

  In metal materials including iron and steel, mechanical properties change depending on not only the alloy composition but also heating conditions, processing conditions, and cooling conditions. The mechanical properties of the metal material include, for example, strength (yield stress, yield strength, hardness, etc.), toughness (brittle transition temperature, etc.), and formability (r value, etc.).

  Adjustment of the alloy composition is performed by controlling the amount of the component elements added. In addition, at the time of component adjustment, one lot unit is large, for example, a component adjustment furnace that can hold molten steel of about 100 tons is used. Each product is about 15 tons, and it is impossible to change the amount of component elements added for each product. In order to manufacture a rolled product of a material requested by a customer, it is important to build the material by appropriately controlling heating conditions, processing conditions, and cooling conditions.

  In recent years, various attempts have been made to create a structure material of a metal material according to usage. For example, when a metal material is cooled after hot rolling, there is a method in which the material is made by jetting a large amount of cooling water at a high pressure. In this method, the metal structure is changed by increasing the cooling rate. Thereby, desired tensile strength and ductility can be given to the product. In order to build such a material, a more advanced technique is required as compared with the prior art. For example, when building materials, advanced techniques such as large strain processing and high-precision management of material temperature are required.

  Conventionally, with regard to heating conditions, processing conditions, and cooling conditions, a target value for heating temperature, a target value for dimensions after processing, a target value for cooling rate, etc. are set for each product specification so that these target values are achieved. A method of performing temperature control and dimensional control has been generally adopted. In addition, about each target value, the value was determined based on experience over many years. However, in recent years, requirements for product specifications have become increasingly sophisticated and diversified, and it has become necessary to manage mechanical properties more strictly than the management performed in the conventional warranty range.

  Conventionally, as defined in JIS (Japanese Industrial Standard), the condition (allowable range) is that the mechanical properties exceed the reference value. For example, a tensile test was performed using a sample taken out from the product, and it was determined whether or not the measured value exceeded the reference value. Recently, however, higher precision is required in the process after product shipment. In the conventional tolerance range as described above, for example, it may not be sufficient in a molding process (drawing, bending, pressing, etc.) which is a lower process. Cases that are too hard to form, cases where the amount of spring back after pressing (elastic recovery amount) is too large and shape freezing properties are poor, and cases where edges break during molding may occur. For this reason, in the setting method based on experience and the management method of mechanical property, the above-mentioned each target value has not necessarily been controlled appropriately.

  In addition, as a conventional method for managing the rolling process step, the temperature of the entire rolling coil is managed using the output value of the thermometer arranged in the rolling line, and further, the mechanical properties closely related to the rolling temperature are managed. There is something. Specifically, thermometers are arranged on the heating furnace exit side, roughing mill entry side and exit side, finish rolling mill entry side and exit side, and coiler entry side of the rolling line, respectively. A thermometer measures the temperature of the center part in a sheet | seat width direction (henceforth only a "width direction") among to-be-rolled materials. Then, control is performed so that the output value from the thermometer matches the target temperature determined based on experience from the host computer.

  Thus, conventionally, when managing the rolling process steps, the mechanical properties in the width direction of the material to be rolled were not considered. In some special materials (for example, materials containing a large amount of Si), edge cracking may occur during rolling. Conventionally, the temperature of the width direction center part of a to-be-rolled material was directly managed based on experience, and as a result, the temperature of the width direction edge part of a to-be-rolled material was managed indirectly.

  Further, the rolling line may be provided with means for increasing the temperature at the end in the width direction of the material to be rolled and means for preventing the temperature at the end in the width direction of the material to be rolled from decreasing. For example, an edge heater installed on the exit side of the finishing mill and an edge mask installed on the run-out table correspond to the above means. The edge mask is equipment for preventing cooling water from being applied to the widthwise end of the material to be rolled.

  Furthermore, in recent years, in order to verify the effect of the above means, a scan pyrometer may be installed before and after the above means. If a scan pyrometer is used, the temperature distribution in the width direction of the material to be rolled can be measured. In addition, a multi-gauge recently adopted in a rolling line also employs a scan pyrometer in order to use the temperature distribution in the width direction of the material to be rolled for correcting the measured value. The multi-gauge has a form in which a plurality of X-ray detectors are arranged in the width direction of the material to be rolled. If a multigauge is used, the thickness distribution in the width direction can be measured. That is, the multi-gauge is a composite measuring instrument that measures the plate thickness, crown, plate width, and the like with a single unit. The measurement accuracy of multigauges has improved significantly in recent years. Since it is cheaper to arrange one multi-gauge than to arrange a thickness gauge, crown gauge, and sheet width gauge, the introduction of multi-gauges into rolling lines is progressing.

  Thus, equipment for measuring the temperature distribution in the width direction of the material to be rolled is being introduced into the rolling line. Some attempts have been made to utilize the measured temperature distribution in the width direction of the rolled material for control. For example, Patent Document 1 discloses a method for controlling a cooling pattern in a runout table.

JP 2009-233724 A

  In the control method described in Patent Document 1, the temperature in the width direction of the material to be rolled is derived by calculation using a temperature model, and the derived value is used as it is. The temperature model is a model for calculating the heat balance per examination volume and predicting (estimating) the temperature. The boundary condition on the surface, which is one of the heat balances, is not always clear. For this reason, even if the temperature is predicted using a temperature model, the predicted value always includes a model error. The one described in Patent Document 1 has a problem that sufficient prediction accuracy cannot be maintained.

  The present invention has been made to solve the above-described problems. An object of the present invention is to provide a temperature distribution prediction apparatus capable of accurately predicting a temperature distribution in the sheet width direction of a material to be rolled.

  The temperature distribution predicting apparatus according to the present invention is based on the first central temperature measuring means for measuring the surface temperature of the center part in the width direction of the material to be rolled that passes through the first position, and the measurement value by the first central temperature measuring means. A first central temperature calculating means for calculating a surface temperature of the central portion in the width direction of the material to be rolled that passes through the second position downstream from the first position and the third position downstream from the first position and upstream from the second position; The first width direction temperature measuring means for measuring the surface temperature at the arbitrary point in the width direction of the material to be rolled that passes through the second position, the first measured value by the first central temperature measuring means and the first width direction temperature measuring means, and the first Width direction temperature calculation means for calculating the surface temperature of an arbitrary point in the width direction of the material to be rolled passing through the third position based on the calculated values of the second position and the third position by the central temperature calculation means. Is.

  With the temperature distribution prediction apparatus according to the present invention, the temperature distribution in the sheet width direction of the material to be rolled can be accurately predicted.

It is a figure which shows the structure of a rolling line. It is a figure which shows the structure of the temperature distribution prediction apparatus in Embodiment 1 of this invention. It is a figure for demonstrating the function of a center temperature calculation means. It is a figure for demonstrating the function of a center temperature calculation means. It is a figure for demonstrating each function of a central temperature calculation means and a central temperature correction means. It is a figure for demonstrating each function of the width direction temperature measurement means and a longitudinal direction temperature prediction means. It is a figure for demonstrating the function of a longitudinal direction temperature prediction means.

  The present invention will be described in detail with reference to the accompanying drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. The overlapping description will be simplified or omitted as appropriate.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a rolling line. FIG. 1 shows a hot rolling line for producing a steel plate as an example of a rolling line that can use the temperature distribution prediction apparatus according to the present invention. The hot rolling line shown in FIG. 1 is a line for producing a rolled product from a rolled material (hereinafter referred to as “slab”). The arrow shown in FIG. 1 represents the direction (rolling direction) through which the material to be rolled (hereinafter referred to as “rolled material”) flows. In the following, the expression “rolled material” is used to indicate a state in the process of being completed from a slab as a rolled product.

  In addition to the hot rolling line as shown in FIG. 1, the present temperature distribution prediction apparatus is used for a thick plate hot plate thickness line, a shape steel hot rolling line, a flat steel hot rolling line, and a steel bar hot rolling line. It can be used for such a rolling line.

  The hot rolling line consists of the heating furnace 1, HSB 2, rough edger 3, rough horizontal rolling mill 4, roughing side thermometer 5, edge heater 6a, bar heater 6b, finishing input side thermometer 7, FSB8, F1 edger from the upstream side. 9, a finishing mill 10, a multi-gauge 11, a finishing delivery thermometer 12, a run-out table 13, a coiler entry-side thermometer 14, and a downcoiler 15.

  A hot rolling line is provided with the conveyance table which conveys a to-be-rolled material. The transfer table is arranged so as to connect the devices indicated by reference numerals 1 to 15. Devices such as the rough horizontal rolling mill 4, the finish rolling mill 10, and the conveyance table provided in the hot rolling line are driven by an electric motor and / or a hydraulic device.

  The heating furnace 1 is a furnace for heating the slab.

  The HSB 2 is an apparatus for removing an oxide film (scale) formed on the surface of the slab. When the slab is heated by the heating furnace 1, an oxide film is formed on the surface thereof. The oxide film formed on the surface of the slab is removed by, for example, spraying high pressure water from the nozzle of HSB2.

  The rough edger 3 is an apparatus for reducing the material to be rolled in the width direction. The rough edger 3 is an apparatus for improving the width accuracy of the rolled product. The rough edger 3 is arranged on the upstream side of the rough horizontal rolling mill 4. The rough edger 3 has its rollers in contact with the material to be rolled from the side. The rough edger 3 deforms the material to be rolled so that the width of the material to be rolled becomes narrow.

  The rough horizontal rolling mill 4 is an apparatus for reducing the material to be rolled in the plate thickness direction. The rough horizontal rolling mill 4 deforms the material to be rolled so that the thickness of the material to be rolled becomes thin. The rough horizontal rolling mill 4 is provided with a single or a plurality of stands each having a set of rolling rollers. In rough rolling, a plurality of passes are required to obtain a desired thickness for the material to be rolled. For this reason, the rough horizontal rolling mill 4 often includes a reversible rolling mill. The pass means that the material to be rolled passes between the rolling rollers.

  The rough horizontal rolling mill 4 is provided with a device called a descaler. A descaler is an apparatus that applies high-pressure water to a material to be rolled, which is a semi-finished product, and removes an oxide film formed on the surface of the material to be rolled. Since rough rolling is performed at a high temperature, an oxide film is easily formed on the surface of the material to be rolled. When performing rough rolling, it is necessary to appropriately use an apparatus for removing an oxide film such as a descaler.

  The roughing side thermometer 5 measures the temperature of the surface (for example, the upper surface) of the material to be rolled. The roughing side thermometer 5 is arranged on the outlet side (downstream side) of the rough horizontal rolling mill 4. When the rough rolling is completed and the material to be rolled passes through the rough horizontal rolling mill 4, the surface temperature is measured by the roughing side thermometer 5. The position where the roughing side thermometer 5 measures the temperature is set in advance in the center in the width direction of the material to be rolled. When the material to be rolled passes below the roughening side thermometer 5, the surface temperature of the central portion in the width direction is measured by the roughening side thermometer 5 from the tip to the tail end.

  The edge heater 6a is a device for raising the temperature of the material to be rolled. After the material to be rolled is extracted from the heating furnace 1, the temperature gradually decreases while being conveyed by the conveyance table. In particular, the temperature of the end portions (one side portion and the other side portion) in the width direction of the material to be rolled tends to be lower than that in the center portion in the width direction. The edge heater 6a raises the temperature of the width direction edge part of a to-be-rolled material by induction heating of electromagnetic force, for example.

  The bar heater 6b is a device for raising the temperature of the material to be rolled. After the material to be rolled is extracted from the heating furnace 1, the temperature gradually decreases while being conveyed by the conveyance table. The bar heater 6b raises the temperature of the material to be rolled over the width direction by induction heating of electromagnetic force. In addition, since the tail end part of the longitudinal direction of a to-be-rolled material is rolled from a front-end | tip part, the temperature at the time of actually rolling with the finishing mill 10 tends to fall. The output of the bar heater 6b is appropriately changed according to the position in the longitudinal direction of the material to be rolled. Thereby, the temperature of the material to be rolled is controlled so as to rise to a desired value in the longitudinal direction.

  The finishing entry thermometer 7 measures the temperature of the surface (for example, the upper surface) of the material to be rolled. The finishing entry thermometer 7 is disposed on the entry side of the finishing mill 10. A relatively long distance is provided between the rough horizontal rolling mill 4 and the finish rolling mill 10. The finish entry temperature of the material to be rolled is closely related to the prediction of the deformation resistance of the material. For this reason, the surface temperature of the material to be rolled is measured by the finishing entry thermometer 7 immediately before being rolled by the finishing mill 10. The position at which the finishing entry thermometer 7 measures the temperature is set in advance in the center in the width direction of the material to be rolled. When the material to be rolled passes under the finishing entry thermometer 7, the surface temperature of the central portion in the width direction is measured by the finishing entry thermometer 7 from the front end to the tail end.

  In addition, when the roughing side thermometer 5 is provided in the hot rolling line, based on the measured value of the roughing side thermometer 5, you may obtain | require the finishing input side temperature of a to-be-rolled material by calculation. In such a case, it is necessary to perform highly accurate temperature prediction in consideration of the conveyance time from the installation position of the roughing-side thermometer 5 to the predetermined position on the entry side of the finishing mill 10.

  The FSB 8 is an apparatus for removing an oxide film formed on the surface of the slab. The FSB 8 is used to improve the surface condition of the material to be rolled after finish rolling. The FSB 8 is disposed on the entry side of the finishing mill 10. A relatively long distance is provided between the rough horizontal rolling mill 4 and the finish rolling mill 10. For this reason, while the material to be rolled is conveyed from the rough horizontal rolling mill 4 to the finishing mill 10, an oxide film is easily formed on the surface thereof. The material to be rolled is sprayed with high-pressure water from the nozzle of the FSB 8 so that the oxide film formed on the surface is removed immediately before finishing rolling by the finishing mill 10 is started.

  The F1 edger 9 is an apparatus for reducing the material to be rolled in the width direction. The F1 edger 9 is an apparatus for improving the width accuracy of the rolled product. The F1 edger 9 is arranged on the entry side of the finishing mill 10. As for F1 edger 9, the roller contacts a material to be rolled from the side. The F1 edger 9 deforms the material to be rolled as long as the width of the material to be rolled is not buckled.

  The finish rolling mill 10 is an apparatus for reducing the material to be rolled in the plate thickness direction. The finish rolling mill 10 deforms the material to be rolled so that the thickness (sheet thickness) of the material to be rolled falls within the target product accuracy of the rolled product. The finish rolling mill 10 is composed of, for example, a tandem rolling mill in which a plurality of rolling mills called stands are arranged.

  The multigauge 11 is a composite measuring instrument that can perform various measurements with a single device. The multigauge 11 has, for example, a form in which a plurality of X-ray detectors are arranged in the width direction of the material to be rolled. The multigauge 11 measures, for example, the plate thickness distribution in the width direction of the material to be rolled. By preparing one multigauge 11, the plate thickness, crown, and plate width of the material to be rolled can be measured.

  As described above, in recent years, the measurement accuracy of the multigauge 11 has been greatly improved. For this reason, it is cheaper to arrange one multi-gauge 11 than to arrange a thickness gauge, a crown gauge, and a sheet width gauge, and the introduction of the multi-gauge 11 to the hot rolling line is progressing. The multigauge 11 includes a thermometer and a thermal image device therein. The multigauge 11 measures the temperature of the material to be rolled, and uses the measured value for correcting the detection value of the X-ray detector.

  The finishing delivery thermometer 12 measures the temperature of the surface (for example, the upper surface) of the material to be rolled. The finishing delivery thermometer 12 is disposed on the delivery side of the finishing mill 10. The temperature of the material to be rolled is closely related to the formation of metal structure of the product and the material (tensile strength, yield stress, elongation, etc.). For this reason, the temperature of a to-be-rolled material needs to be managed appropriately. When finish rolling is completed and the material to be rolled passes through the finish rolling mill 10, the surface temperature is measured by the finish delivery thermometer 12. The position where the finishing delivery thermometer 12 measures the temperature is set in advance in the center in the width direction of the material to be rolled. When the material to be rolled passes under the finishing delivery thermometer 12, the surface temperature of the central portion in the width direction is measured by the finishing delivery thermometer 12 from the front end to the tail end.

  The runout table 13 is a device for cooling the material to be rolled. The run-out table 13 is disposed on the exit side of the finishing mill 10. The run-out table 13 supplies cooling water to the surface of the material to be rolled from, for example, a nozzle in order to control the temperature of the material to be rolled. The run-out table 13 includes a number of nozzles in the longitudinal direction of the material to be rolled (conveying direction of the conveying table). These nozzles are divided into a plurality of banks. Control of the nozzles is performed for each bank. That is, water cooling is performed in the bank that supplies the cooling water, and air cooling is performed in the bank that is not supplied with the cooling water. The supply of cooling water may be controlled for each nozzle.

  The runout table 13 may be provided with an edge mask (not shown). The edge mask is for preventing the temperature at the end in the width direction of the material to be rolled from decreasing. An edge mask is arrange | positioned so that the width direction edge part of a to-be-rolled material may be covered. The edge mask prevents the cooling water from the nozzle from being directly applied to the widthwise end of the material to be rolled.

  The coiler entry side thermometer 14 measures the temperature of the surface (for example, the upper surface) of the material to be rolled. The coiler inlet side thermometer 14 is arranged on the inlet side of the down coiler 15. After the material to be rolled passes through the run-out table 13, the surface temperature is measured by the coiler entry-side thermometer 14 immediately before being wound by the downcoiler 15. The position where the coiler inlet side thermometer 14 measures the temperature is set in advance in the center in the width direction of the material to be rolled. When the material to be rolled passes below the coiler inlet side thermometer 14, the surface temperature of the central portion in the width direction is measured by the coiler inlet side thermometer 14 from the front end to the tail end.

  The downcoiler 15 is an apparatus for winding up the material to be rolled. The material to be rolled is wound up by the downcoiler 15 to become a product (including a semi-finished product for the next process) and is transported by a transport device.

The hot rolling line includes a thermal imaging device 16 in addition to the devices indicated by reference numerals 1 to 15.
The thermal image device 16 measures the temperature of the surface of the material to be rolled (for example, the upper surface or the upper surface and the lower surface) at least at a plurality of locations in the width direction of the material to be rolled. When the material to be rolled passes between the thermal imaging devices 16, the surface temperature at a plurality of locations in the width direction is measured by the thermal imaging device 16 from the front end to the tail end.

  The thermal image device 16 is preferably arranged before and after the device for improving the temperature of the material to be rolled. For example, the thermal imaging device 16 is disposed on the entry side and / or exit side of the device. As an example, FIG. 1 shows a case in which the thermal imaging devices 16 are installed before and after the edge heater 6 a and the bar heater 6 b and before and after the run-out table 13. A thermal imaging device 16 disposed on the entry side of the runout table 13 is provided inside the multigauge 11.

  For example, a near infrared camera is used as the thermal image device 16. By using a near-infrared camera as the thermal image device 16, the temperature distribution in the width direction of the material to be rolled can be captured as an image. That is, the surface temperature can be measured over the entire width direction of the material to be rolled. Further, the surface temperature can be continuously measured in the longitudinal direction of the material to be rolled. For this reason, the temperature of the whole surface of a material to be rolled can be measured.

  The arrangement of the thermal image device 16 is not limited to the example shown in FIG. The arrangement of the thermal image device 16 is determined as necessary. For example, the thermal image device 16 may be installed only before and after the runout table 13. Further, the thermal image device 16 may be installed only before and after the edge heater 6a and the bar heater 6b. The thermal imaging device 16 may be installed before and after another device (for example, the finishing mill 10).

FIG. 2 is a diagram showing the configuration of the temperature distribution predicting apparatus according to Embodiment 1 of the present invention.
The temperature distribution prediction apparatus includes, for example, a central temperature measuring unit 17, a central temperature calculating unit 18, a central temperature correcting unit 19, a width direction temperature measuring unit 20, a longitudinal direction temperature predicting unit 21, and a temperature using unit 22.

  Central temperature measuring means 17 measures the temperature of the surface of the material to be rolled. The position where the central temperature measuring means 17 measures the temperature is set in advance at the center in the width direction of the material to be rolled. The center temperature measuring means 17 continuously measures the surface temperature of the center part in the width direction of the material to be rolled over the length of the material to be rolled, that is, from the front end to the tail end of the material to be rolled.

  The central temperature measuring means 17 is composed of a radiation thermometer, for example. In the example shown in FIG. 1, the roughing-side thermometer 5, the finishing-inside thermometer 7, the finishing-outside thermometer 12, and the coiler-inside thermometer 14 correspond to the central temperature measuring means 17. Further, the temperature in the vicinity of the center part may be taken out using the function of measuring the surface temperature of the center part in the width direction of the material to be rolled in the thermal image device 16 and used as the center temperature measuring means 17.

  The arrangement of the central temperature measuring means 17 is determined as necessary from the viewpoint of cost and the necessity of temperature management. In addition, arrangement | positioning of the center temperature measurement means 17 is not limited to the example shown in FIG. The installation location of the central temperature measurement means 17 may be limited to a location where temperature management is a minimum requirement. For example, the central temperature measuring means 17 may be installed only on the finishing delivery side (FDT) and the coiler entry side (CT).

  The center temperature calculation means 18 calculates the temperature distribution in the plate thickness direction at the center in the width direction of the material to be rolled. In the temperature control (CTC: Coiling Temperature Control) and the technology for predicting the material in the runout table 13, it is necessary to calculate the temperature transition of the material to be rolled. For example, in CTC, the temperature transition of the material to be rolled when passing through the runout table 13 is required. Based on the temperature of the material to be rolled measured by the central temperature measuring means 17, the central temperature calculating means 18 performs the above calculation using boundary conditions such as water cooling and air cooling, a heat conduction coefficient, and the like.

  The function of the central temperature calculation means 18 will be specifically described below with reference to FIGS. 3 and 4 are diagrams for explaining the function of the central temperature calculation means 18. 3 and 4 show cross sections obtained by cutting the material to be rolled in a direction perpendicular to the longitudinal direction thereof.

  The central temperature calculation means 18 calculates the temperature distribution in the plate thickness direction by a calculation method using a difference method, for example. N shown in FIGS. 3 and 4 is the number of elements obtained by dividing the material to be rolled. In the calculation method using the difference method, the area from the surface of the material to be rolled to the center of the material to be rolled is divided into N elements, and heat input / output between the elements is considered.

  N is a number that divides half the thickness of the material to be rolled. For this reason, the total number of divisions from the upper surface to the lower surface of the material to be rolled is 2N-1 as shown in FIG.

  Let the space step representative width be Δx. First, an element is taken in the shape of a square ring at the outermost side of the material to be rolled, with a width Δx / 2 that is half the representative width of the space. That is, this element is a portion that enters the inside of the material to be rolled by a distance Δx / 2 from the top surface, the bottom surface, one side surface, and the other side surface of the material to be rolled. Next, an element is taken in a square ring shape with a space step representative width Δx immediately inside the element. That is, this element is a portion that enters the inside of the material to be rolled by a distance Δx from the outermost element. Thereafter, the elements are divided in the same manner, and the elements are formed in a square ring shape with a space step representative width Δx immediately inside the formed elements. When the (N-1) th division is completed, a central element is formed inside. Further, the ring-shaped element excluding the central element is divided into an upper half and a lower half so that later calculations can be performed separately on the upper surface side and the lower surface side of the material to be rolled. Thereby, a to-be-rolled material is divided | segmented into the element of the total number 2N-1.

Next, the volume and boundary area of each element divided into the total number 2N−1 are calculated.
In the following calculation, the unit length is taken in the longitudinal direction of the material to be rolled, the plate thickness of the material to be rolled is H, and the plate width is B. Further, the element on the uppermost side of the material to be rolled is the first element, the element immediately below the first element is the second element,..., The element at the center of the material to be rolled is the Nth element,. The element on the lowermost side of the material to be rolled is defined as the second N-1 element.
The volume and boundary area of each element can be calculated as follows.

第２要素の体積：

第３要素の体積：

第Ｎ要素（中心要素）の体積：

第２Ｎ−３要素の体積：

第２Ｎ−２要素の体積：

第２Ｎ−１要素の体積：

Volume of the first element:

Volume of the second element:

Third element volume:

Volume of Nth element (central element):

Volume of 2nd N-3 element:

Volume of the second N-2 element:

Volume of 2nd N-1 element:

第１要素と第２要素との間の境界面面積：

第２要素と第３要素との間の境界面面積：

第Ｎ−１要素と第Ｎ要素との間の境界面面積：

第２Ｎ−３要素と第２Ｎ−２要素との間の境界面面積：

第２Ｎ−２要素と第２Ｎ−１要素との間の境界面面積：

第２Ｎ−１要素と周囲との間の境界面面積：

Interface area between the first element and the surrounding area:

Interface area between the first element and the second element:

Interface area between the second element and the third element:

Interface area between the (N-1) th element and the Nth element:

Interface area between the second N-3 element and the second N-2 element:

Interface area between 2nd N-2 element and 2nd N-1 element:

Interface area between the second N-1 element and the surrounding area:

Next, the inflow / outflow heat amount between each element in the time step Δt is calculated. FIG. 4 shows the amount of heat input and output between the elements. In hot rolling, the material to be rolled is subjected to various inflow and outflow processes while being conveyed on the line. This process includes, for example, radiation, cooling, processing frictional heat generation, roll heat transfer, and the like.
About the element arrange | positioned at the outermost side among the elements of a to-be-rolled material, inflow heat amount can be expressed as follows.

ここで、

here,

  Regarding the elements arranged inside the elements of the material to be rolled, that is, the second to the (2N-2) elements, the inflow heat quantity can be expressed as follows. The inflow / outflow heat of each element arranged inside the material to be rolled is heat conduction due to a temperature difference from an adjacent element, and processing heat generation in the rolling zone.

ここで、

here,

ここで、

Next, the temperature of each element is calculated. The temperature change amount of each element can be expressed as follows.

here,

ここで、

The temperature of each element at time step (j + 1) can be calculated by the following equation. The time step (j + 1) is the time after the time step Δt has elapsed from the time step j.

here,

  The central temperature calculation means 18 calculates the inflow heat amount, temperature change amount, and temperature of each element for each time step. The central temperature calculation means 18 performs the above calculation for each element from the first element to the (2N-1) th element from the start to the end of conveyance of the material to be rolled. Thereby, the temperature distribution (including surface temperature) in the plate thickness direction and its transition at the center in the width direction of the material to be rolled can be obtained.

  FIG. 5 is a diagram for explaining the functions of the central temperature calculation means 18 and the central temperature correction means 19. A broken line A in FIG. 5 indicates the temperature of the central portion in the width direction of the material to be rolled, calculated by the central temperature calculation means 18. For example, the broken line A is the calculated temperature at the measurement position of the finishing delivery thermometer 12.

  In addition, in the said description, the case where the temperature inside a to-be-rolled material was calculated was demonstrated by carrying out the element division | segmentation of the to-be-rolled material annularly from the outer side to the inner side. The central temperature calculating means 18 may calculate the internal temperature by dividing the material to be rolled into other elements. For example, the material to be rolled may be divided into a plate thickness direction and a plate width direction. That is, the material to be rolled may be divided into two-dimensional meshes. However, in the case of the above-described division method, for example, even for a thick material to be rolled such as a slab, the temperature prediction calculation is performed by the differential method in consideration of the temperature and boundary conditions of the side surface of the material to be rolled. be able to. Further, the number of divisions can be reduced, and the computer load can be reduced when online control calculation is performed in actual operation.

  The temperature at the center in the width direction of the material to be rolled (temperature distribution in the thickness direction) calculated by the center temperature calculation means 18 includes errors due to boundary conditions and model parameters. The central temperature correction means 19 corrects the calculation result (predicted temperature) by the central temperature calculation means 18. The central temperature correction means 19 performs the above correction based on the surface temperature (actual value) of the material to be rolled measured by the central temperature measurement means 17.

  For example, the center temperature correcting means 19 is a plate thickness at the center in the width direction of the material to be rolled so that the surface temperature of the material to be rolled calculated by the center temperature calculating means 18 matches the actual measurement value by the center temperature measuring means 17. Recalculate the temperature in the direction. For example, the central temperature correcting means 19 obtains a solid line B by translating the broken line A so as to pass an actual measurement value obtained by the finishing delivery thermometer 12. That is, the solid line B indicates the temperature in the plate thickness direction at the center in the width direction of the material to be rolled after being corrected by the center temperature correcting means 19. Thereby, it is possible to obtain a more reliable temperature distribution of the material to be rolled, that is, a temperature distribution in the thickness direction at the center in the width direction.

  The width direction temperature measuring means 20 measures the surface temperature at an arbitrary point in the width direction of the material to be rolled. The position where the width direction temperature measuring means 20 measures the temperature is preset in at least a plurality of locations in the width direction of the material to be rolled. The width direction temperature measuring means 20 continuously measures the surface temperature of the material to be rolled over the length of the material to be rolled, that is, from the front end to the tail end of the material to be rolled. In the example shown in FIG. 1, the thermal image device 16 corresponds to the width direction temperature measuring means 20.

  The arrangement of the width direction temperature measuring means 20 is determined as necessary from the viewpoint of cost and the necessity of temperature management. In addition, arrangement | positioning of the width direction temperature measurement means 20 is not limited to the example shown in FIG. The installation location of the width direction temperature measurement means 20 may be limited to a location where temperature management is a minimum requirement. In the following, a specific description will be given by taking as an example a case where the thermal imaging device 16 is installed on the entry side and the exit side of the runout table 13.

  FIG. 6 is a diagram for explaining the functions of the width direction temperature measurement means 20 (thermal image device 16) and the longitudinal direction temperature prediction means 21. FIG. 7 is a diagram for explaining the function of the longitudinal temperature predicting means 21.

  The thermal imager 16 can measure the surface temperature over the entire width direction of the material to be rolled. A solid line C in FIG. 6 indicates the surface temperature of a certain portion of the material to be rolled, which is measured by the thermal image device 16 provided on the entry side of the runout table 13. A solid line D in FIG. 6 indicates the surface temperature of the same portion of the material to be rolled, which is measured by the thermal imaging device 16 provided on the exit side of the runout table 13.

  The material to be rolled has a high temperature at the center in the width direction, and the temperature decreases as it approaches the end in the width direction. For example, the temperature at point E is higher than the temperature at the corresponding point F on both the entry side and exit side of the runout table 13. Further, the material to be rolled is cooled by the runout table 13. In the water-cooled region of the runout table 13, the cooling rate is fast, and in the air-cooled region, the cooling rate is slow. FIG. 6 shows such a state.

  The longitudinal temperature predicting means 21 has a function of calculating the surface temperature at an arbitrary point in the width direction of the material to be rolled and a function of calculating a temperature distribution in the thickness direction at an arbitrary point in the width direction of the material to be rolled. First, with reference to FIG. 7, the function which calculates the surface temperature of the arbitrary points of the width direction of a to-be-rolled material among the functions of the longitudinal direction temperature prediction means 21 is demonstrated.

  In CTC, in general, feedforward control using actual temperature values in FDT is often performed. In such a case, for example, the central temperature calculation means 18 calculates the temperature pattern of the material to be rolled on the runout table 13 from the actual temperature value in the FDT. And the longitudinal direction temperature prediction means 21 calculates the surface temperature of the width direction arbitrary point of the to-be-rolled material in a certain position on the runout table 13 based on the actual temperature value and the calculated value in CT. A specific calculation method is shown in Formula 1.

である。 here,

It is.

  Next, a calculation method in a case where correction is performed using the actual temperature value in FDT and the actual temperature value in CT from the calculated value obtained by the setting calculation will be described. In such a case, the central temperature calculation means 18 performs the calculation of the following formula 2 in addition to the calculation of the above formula 1.

である。 here,

It is.

  Further, the longitudinal temperature predicting means 21 is based on the surface temperature at an arbitrary point in the width direction of the rolled material obtained by the above calculation and the temperature distribution in the plate thickness direction of the rolled material calculated by the central temperature calculating means 18. Then, the temperature distribution in the plate thickness direction at an arbitrary point in the width direction of the material to be rolled is calculated. For example, when the temperature distribution calculated by the central temperature calculation means 18 is the broken line A shown in FIG. 5, the longitudinal direction temperature prediction means 21 passes the value obtained from Expression 1 (or Expression 1 and Expression 2). Thus, the broken line A is translated to obtain a temperature distribution in the plate thickness direction at an arbitrary point in the width direction of the material to be rolled.

  The temperature distribution in the width direction and the plate thickness direction of the material to be rolled obtained in this way is used for phase transformation calculation occurring on the runout table 13, quality control, and the like.

  In addition, although CTC was demonstrated in the said example, it cannot be overemphasized that the same control can be performed also in the temperature control in the other part on a rolling line. For example, the temperature distribution can be obtained with the entrance side of the edge heater 6a and the bar heater 6b as the first position and the exit side as the second position.

  1 Heating furnace, 2 HSB, 3 Coarse edger, 4 Coarse horizontal rolling mill, 5 Coarse side thermometer, 6a Edge heater, 6b Bar heater, 7 Finishing input side thermometer, 8 FSB, 9 F1 edger, 10 Finishing mill, DESCRIPTION OF SYMBOLS 11 Multi gauge, 12 Finishing side thermometer, 13 Runout table, 14 Coiler inlet side thermometer, 15 Downcoiler, 16 Thermal imaging device, 17 Central temperature measurement means, 18 Central temperature calculation means, 19 Central temperature correction means, 20 Width Direction temperature measurement means, 21 Longitudinal temperature prediction means, 22 Temperature use means

Claims (4)

A first central temperature measuring means for measuring the surface temperature of the central portion in the width direction of the material to be rolled that passes through the first position;
Based on the measurement value by the first central temperature measurement means, the material to be rolled that passes through the second position downstream from the first position and the third position downstream from the first position and upstream from the second position. First central temperature calculating means for calculating the surface temperature of the central portion in the width direction;
A first width direction temperature measuring means for measuring a surface temperature at an arbitrary point in the width direction of the material to be rolled that passes through the second position;
Based on the measured values by the first central temperature measuring means and the first width direction temperature measuring means and the calculated values of the second position and the third position by the first central temperature calculating means, the third position is determined. A width direction temperature calculating means for calculating a surface temperature at an arbitrary point in the width direction of the material to be rolled passing therethrough;
A temperature distribution predicting device.

A second width direction temperature measuring means for measuring a surface temperature at an arbitrary point in the width direction of the material to be rolled that passes through the first position;
A second central temperature calculating means for calculating a surface temperature of a center portion in the width direction of the material to be rolled that passes through the first position and the third position;
A second central temperature measuring means for measuring the surface temperature of the central portion in the width direction of the material to be rolled that passes through the second position;
Further comprising
The width direction temperature calculation means includes a measurement value by the second width direction temperature measurement means and the second center temperature measurement means, and a calculation value of the first position and the third position by the second center temperature calculation means. The temperature distribution prediction apparatus according to claim 1, wherein the surface temperature at an arbitrary point in the width direction of the material to be rolled that passes through the third position is calculated based on the above.

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