阅读说明：本技术 热轧无头轧制生产线的钢板温度控制装置 (Steel plate temperature control device of hot rolling endless rolling production line ) 是由 下谷俊人 于 2018-10-19 设计创作，主要内容包括：提供一种热轧无头轧制生产线的钢板温度控制装置,该钢板温度控制装置在无头轧制中执行移动中变更钢板的板厚的移动板厚变更的情况下,通过适当地控制钢板的锥形部分的温度,能够实现提升锥形部分附近的产品品质。执行移动中变更钢板的板厚的移动板厚变更的情况下,执行锥形部分板厚计算处理和感应加热装置输出计算处理。锥形部分板厚计算处理中,计算根据粗轧机的板厚变更动作产生的钢板的锥形部分的板厚。感应加热装置输出计算处理使用规定了为了达成目标温度或目标升温量的钢板的板厚和感应加热装置的输出之间关系的图或函数,基于由锥形部分板厚计算处理计算出的锥形部分的板厚,计算锥形部分通过感应加热装置之时感应加热装置的输出。(Provided is a steel plate temperature control device for a hot rolling endless rolling line, which can improve the product quality near a tapered part by properly controlling the temperature of the tapered part of a steel plate when a moving plate thickness change is performed to change the plate thickness of the steel plate during endless rolling. When a moving plate thickness change is performed to change the plate thickness of the steel plate during movement, a tapered portion plate thickness calculation process and an induction heating device output calculation process are performed. In the tapered portion thickness calculation process, the thickness of the tapered portion of the steel sheet generated by the thickness change operation of the roughing mill is calculated. The induction heating device output calculation process uses a map or a function that specifies a relationship between the thickness of the steel sheet and the output of the induction heating device in order to achieve the target temperature or the target temperature rise amount, and calculates the output of the induction heating device when the tapered portion passes through the induction heating device, based on the thickness of the tapered portion calculated by the tapered portion thickness calculation process.)

1. A steel plate temperature control device of a hot rolling endless rolling production line is characterized in that,

In a hot rolling endless rolling line in which a steel sheet flows in the order of a roughing mill, an induction heating device, and a finishing mill, the temperature of the steel sheet entering the finishing mill is controlled by the output of the induction heating device,

When a moving plate thickness change is performed in which the plate thickness of the steel plate is changed during movement, the following processing is performed:

A tapered portion plate thickness calculation process of calculating a plate thickness of a tapered portion of the steel plate generated by a plate thickness change operation of the roughing mill; and

And an induction heating device output calculation process of calculating an output of the induction heating device when the tapered portion passes through the induction heating device, based on the thickness of the tapered portion calculated by the tapered portion thickness calculation process, using a map or a function that specifies a relationship between the thickness of the steel sheet and the output of the induction heating device to achieve a target temperature or a target temperature rise.

2. The apparatus for controlling the temperature of a steel sheet in a hot rolling endless rolling line according to claim 1,

In the induction heating device output calculation process, an output of the induction heating device when the tapered portion passes through the induction heating device is calculated based on a plate thickness at a start point of the tapered portion and a plate thickness at an end point of the tapered portion.

3. The apparatus for controlling the temperature of a steel sheet in a hot rolling endless rolling line according to claim 2,

In the induction heating device output calculation process, the output of the induction heating device when the tapered portion passes through the induction heating device is calculated based on plate thicknesses of a plurality of intermediate target points set in the rolling direction of the tapered portion.

4. The steel sheet temperature control apparatus of a hot rolling endless rolling line according to any one of claims 1 to 3,

In the induction heating device output calculation process, the output of the induction heating device is continuously changed from the output of the induction heating device corresponding to the plate thickness at the start point of the taper portion to the output of the induction heating device corresponding to the plate thickness at the end point of the taper portion.

5. the steel sheet temperature control apparatus of a hot rolling endless rolling line according to any one of claims 1 to 3,

In the induction heating device output calculation process, the output of the induction heating device is changed in stages from the output of the induction heating device corresponding to the plate thickness at the start point of the taper portion to the output of the induction heating device corresponding to the plate thickness at the end point of the taper portion.

6. The steel sheet temperature control apparatus of a hot rolling endless rolling line according to any one of claims 1 to 5,

In the induction heating device output calculation process, the inlet-side actual temperature or the inlet-side actual historical temperature increase amount of the steel sheet is collected from a thermometer provided on an upstream side of the induction heating device, and the output of the induction heating device is corrected in accordance with a deviation between the inlet-side planned temperature or the inlet-side planned temperature increase amount of the steel sheet and the inlet-side actual temperature or the inlet-side actual historical temperature increase amount, which is a premise of the map or the function.

7. The steel sheet temperature control apparatus of a hot rolling endless rolling line according to any one of claims 1 to 6,

In the induction heating apparatus output calculation process, an outlet-side actual temperature or an outlet-side actual historical temperature increase amount of the steel sheet is collected from a thermometer provided on a downstream side of the induction heating apparatus, and an output of the induction heating apparatus is corrected based on a deviation between the target temperature or the target temperature increase amount and the outlet-side actual temperature or the outlet-side actual historical temperature increase amount.

Technical Field

The present invention relates to a steel sheet temperature control device for a hot rolling endless rolling line in which a steel sheet flows in the order of a roughing mill, an induction heating device, and a finishing mill, and more particularly, to a steel sheet temperature control device for controlling the temperature of a steel sheet entering a finishing mill based on the output of an induction heating device.

Background

In the hot rolling process, a steel plate blank heated to a high temperature by a plate blank heating furnace is conveyed to a production line and sequentially rolled, and finally, the steel plate blank is coiled by a coiling machine. In recent years, due to high demands and diversification of product specifications, the guaranteed ranges of target temperatures at various places on a rolling line, such as the finishing mill inlet side temperature, the finishing mill outlet side temperature, and the coiling temperature, have become more strict than ever before.

For temperature control of steel sheets of a hot rolling process, an induction heating apparatus is introduced. The heating by the induction heating device utilizes joule loss caused by eddy current flowing to cancel out magnetic flux linked with the steel sheet. The induction heating device is high in energy efficiency because it is directly heated, and can be expected to improve the yield because it is rapidly heated. The amount of heat generated from the steel sheet by the induction heating device varies depending on the thickness, width, and speed of the steel sheet. Therefore, in the temperature control of the steel sheet by the induction heating device, the output of the induction heating device is set in accordance with the thickness, width, and speed of the steel sheet in order to achieve a target temperature or heating temperature rise of the steel sheet.

In addition, endless rolling in a rolling line directly connected by a continuous caster and a mill is performed for the improvement of the yield of hot rolling and the stable rolling of thin articles. In the endless rolling, a high-temperature steel slab fed out from a continuous casting machine is conveyed to a production line, sequentially rolled, cut into a roll length in front of a coiler, and coiled. In such headless rolling, a moving plate thickness change may be performed in which the plate thickness of the steel plate is changed during movement. When the moving thickness is changed, a tapered portion in which the thickness continuously changes occurs between the start point and the end point of the change in the thickness.

the tapered portion of the steel plate is a portion that cannot be finally made into a product even if cut. However, temperature control of the tapered portion is not required, however. Since the tapered portion is naturally connected to the front and rear steel plates, if the temperature control of the tapered portion is not performed, the quality of the steel plates before and after the tapered portion, that is, the portion to be a product is adversely affected. In order to finally minimize the area to be cut, the temperature control in the tapered portion is also required to be as strict as the area to be the product.

Patent document 1 discloses a method for controlling the temperature of a steel sheet subjected to endless rolling for joining the trailing end of a leading material and the leading end of a trailing material. According to the method disclosed in patent document 1, the plate thickness in the vicinity of the joint is set based on the relationship between the heating efficiency and the plate thickness, and heating is performed by the induction heating device so that the target temperature on the outlet side of the finishing mill is achieved.

However, the method disclosed in patent document 1 is a method in which a tapered portion is not formed in the steel sheet before and after the change of the moving sheet thickness. In headless rolling in which a continuous casting machine and a mill are directly connected, when the thickness of the steel plate is changed to a tapered portion by moving the plate thickness change, the method disclosed in patent document 1 cannot be applied as it is.

[ Prior art documents ]

[ patent document 1 ] Japanese patent laid-open No. 2000-271607

Disclosure of Invention

In view of the above-described problems, an object of the present invention is to provide a steel sheet temperature control apparatus for a hot rolling endless rolling line, which can improve the product quality in the vicinity of a tapered portion by appropriately controlling the temperature of the tapered portion of a steel sheet when a traveling sheet thickness change is performed to change the sheet thickness of the steel sheet during traveling in endless rolling.

The steel plate temperature control device of a hot rolling endless rolling line according to the present invention is a steel plate temperature control device that controls the temperature of a steel plate entering a finishing mill by the output of an induction heating device in a hot rolling endless rolling line in which the steel plate flows in the order of a roughing mill, the induction heating device, and the finishing mill. The steel sheet temperature control device of the hot rolling endless rolling line according to the present invention is characterized in that, when a moving sheet thickness change for changing the sheet thickness of the steel sheet is performed during movement, the tapered portion sheet thickness calculation processing and the induction heating device output calculation processing described in detail below are executed.

The tapered portion thickness calculation process is a process of calculating the thickness of the tapered portion of the steel sheet generated by the thickness change operation of the roughing mill. For example, if the target thickness of the steel sheet before and after the change in the thickness and the set length of the tapered portion are moved and then the conveying speed of the steel sheet is known, the thickness of the tapered portion passing through the induction heating apparatus can be expressed as a function of time. In the tapered portion plate thickness calculation process, for example, a plate thickness that continuously changes from a start point to an end point of the tapered portion may be calculated. Alternatively, in the taper portion plate thickness calculation process, only the plate thicknesses at the start point and the end point of the taper portion may be calculated. In the taper portion thickness calculation process, a plurality of intermediate target points are set in the rolling direction of the taper portion, and the thickness of each intermediate target point may be calculated in addition to the thicknesses of the start point and the end point of the taper portion.

The induction heating device output calculation process is a process of calculating the output of the induction heating device while the tapered portion passes through the induction heating device. The calculation is performed based on the thickness of the taper portion calculated by the taper portion thickness calculation process using a graph or a function defining a relationship between the thickness of the steel sheet to achieve the target temperature or the target temperature rise amount and the output of the induction heating device. The output of the induction heating device calculated by the induction heating device output calculation processing is set with respect to an induction heating device control device that controls the induction heating device.

By performing the tapered portion thickness calculation process and the induction heating device output calculation process described above, the output of the induction heating device when the tapered portion of the steel sheet passes through the induction heating device can be appropriately controlled in accordance with the continuously changing tapered portion thickness.

In the induction heating device output calculation process, the output of the induction heating device when the tapered portion passes through the induction heating device may be calculated based on the plate thickness at the start point of the tapered portion and the plate thickness at the end point of the tapered portion. In addition to the plate thicknesses of the start point and the end point of the taper portion, the output of the induction heating apparatus when the taper portion passes through the induction heating apparatus may be calculated based on the plate thicknesses of a plurality of intermediate target points set in the rolling direction of the taper portion.

In the induction heating device output calculation process, the output of the induction heating device may be continuously changed from the output of the induction heating device corresponding to the plate thickness at the start point of the taper portion to the output of the induction heating device corresponding to the plate thickness at the end point of the taper portion. Alternatively, in the induction heating device output calculation process, the output of the induction heating device may be changed in stages from the output of the induction heating device corresponding to the plate thickness at the start point of the taper portion to the output of the induction heating device corresponding to the plate thickness at the end point of the taper portion.

In the induction heating device output calculation process, the output of the induction heating device may be corrected in accordance with the temperature condition of the steel sheet entering the induction heating device. For example, if the temperature control of the steel sheet is performed using the target temperature, the actual temperature on the inlet side of the steel sheet is collected from a thermometer provided on the upstream side of the induction heating device, and the output of the induction heating device is corrected according to the deviation between the planned temperature on the inlet side and the actual temperature on the inlet side of the steel sheet, which is an assumption of a graph or a function. If the temperature control of the steel sheet is performed using the target temperature rise amount, the actual historical temperature rise amount on the inlet side of the steel sheet may be collected from a thermometer provided on the upstream side of the induction heating apparatus, and the output of the induction heating apparatus may be corrected according to the deviation between the planned temperature rise amount on the inlet side of the steel sheet and the actual historical temperature rise amount on the inlet side, which is assumed to be a graph or a function.

in the induction heating device output calculation process, the output of the induction heating device may be corrected in accordance with the temperature condition of the steel sheet to be discharged from the induction heating device. For example, if the temperature control of the steel sheet is performed using the target temperature, the actual temperature of the steel sheet on the outlet side may be collected from a thermometer provided on the downstream side of the induction heating apparatus, and the output of the induction heating apparatus may be corrected in accordance with the deviation between the target temperature and the actual temperature on the outlet side. If the temperature control of the steel sheet is performed using the target temperature rise amount, the actual outlet-side history temperature rise amount of the steel sheet may be collected from a thermometer provided on the downstream side of the induction heating apparatus, and the output of the induction heating apparatus may be corrected in accordance with the deviation between the target temperature rise amount and the actual outlet-side history temperature rise amount.

According to the steel sheet temperature control device of the hot rolling endless rolling line according to the present invention, the output of the induction heating device when the tapered portion of the steel sheet passes through the induction heating device can be appropriately controlled in accordance with the continuously changing thickness of the tapered portion. Thus, the product quality in the vicinity of the tapered portion can be improved by achieving the target temperature or the target temperature rise in the tapered portion of the steel sheet entering the finishing mill.

Drawings

Fig. 1 is a diagram showing an example of the structure of a hot rolling endless rolling line.

Fig. 2 is a schematic view showing a case where the thickness of the steel sheet is changed by changing the moving thickness of the endless rolling.

Fig. 3 is a diagram showing a configuration of a steel sheet temperature control device common to the embodiments of the present invention.

Fig. 4 is a diagram illustrating an output calculation process of an induction heating apparatus according to embodiment 1 of the present invention.

Fig. 5 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 2 of the present invention.

Fig. 6 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 3 of the present invention.

Fig. 7 is a diagram illustrating an output calculation process of an induction heating apparatus according to embodiment 3 of the present invention.

Fig. 8 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 4 of the present invention.

Fig. 9 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 5 of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the embodiments shown below, the number of each element, the number, the amount, the range, and the like are mentioned, and the mentioned number is not a limitation of the present invention unless the number is specifically indicated or clearly specified in principle. The structure described in the embodiments shown below is not necessarily essential to the present invention unless otherwise explicitly indicated or clearly and conceptually defined.

1. Structure of hot-rolling endless rolling production line

First, a hot rolling endless rolling line to which the steel sheet temperature control device according to the present invention is applied will be described. Fig. 1 is a diagram showing an example of the structure of a hot rolling endless rolling line. The steel sheet 6 drawn out from the continuous casting machine 1 is heated by the slab heating furnace 2 and drawn out from the rolling line. In the rolling line, the steel sheet 6 passed through the edge trimmer 3 is stretched and thinned to a desired thickness in the roughing mill 4 and the finishing mill 9, and is processed to a desired width.

The roughing mill 4 is constituted by 1 or more rolling stands, and rolls the steel sheet 6 in a direction from the upstream to the downstream so that the sheet thickness or the sheet width of the steel sheet 6 approaches the product size. The roughing mill 4 is also provided with a roughing exit side thermometer 5 for measuring the temperature of the steel sheet. The induction heating device 7 is installed in a production line between the roughing mill 4 and the finishing mill 9, and heats the steel sheet 6 passing through the induction heating device 7.

The finishing mill 9 is composed of a plurality of rolling stands, rolls the steel sheet 6 in a direction from upstream to downstream, and determines final quality regarding dimensions such as a sheet thickness and a sheet width of the steel sheet. The temperature of the steel sheet after finish rolling is measured by a finish rolling mill outlet thermometer 10. Further, it is also possible that a finishing mill inlet side thermometer 8 is provided between the induction heating device 7 and the finishing mill 9.

Downstream of the finishing mill 9, a cooling stand 11 is provided. The cooling table 11 injects water into the steel plate 6 to lower the temperature of the steel plate 6. The steel sheet 6 passing through the cooling table 11 is cut into a roll length by a flying shear 12 before the coiler and is wound into a roll shape by a coiler 13.

When the plate thickness of the steel plate 6 is changed during the movement, the plate thickness is changed without stopping the operation by changing the distance between the rolls of the rolling stages of the roughing mill 4 in stages or by changing the distance between the rolls of the rolling stages of the roughing mill 4 and the finishing mill 9 in stages. Fig. 2 is a schematic view showing a state in which the thickness of the steel plate 6 is changed by changing the moving thickness of the endless rolling. As shown in fig. 2, during the change of the moving plate thickness, a portion where the plate thickness of the steel plate 6 continuously changes occurs between the stages according to the plate thickness changing operation of the roughing mill 4. The portion remaining from this portion to the exit side of the final stage becomes the tapered portion 6a of the steel plate 6.

2. Structure of steel plate temperature control device

Next, in each embodiment of the present invention, the configuration of a common steel sheet temperature control device will be described with reference to fig. 3. Fig. 3 is a diagram showing an example of the structure of the steel sheet temperature control device. The hot rolling endless rolling line is provided with a rolling setting device 15 for setting various parameters relating to rolling. The rolling setting device 15 is, for example, a computer including at least one processor and at least 1 memory. The program stored in the memory is executed by a processor, and the rolling setting device 15 functions as a computer and a steel plate temperature control device.

The rolling setting device 15 as a steel sheet temperature control device includes a sheet thickness setting calculation unit 17 and an induction heating device output calculation unit 19. The plate thickness setting calculation section 17 includes a moving plate thickness change calculation section 16. These calculation units 16, 17, and 19 are not provided as hardware, but are realized by software using a program stored in a memory of the rolling setting device 15. The functions of the calculation units 16, 17, and 19 constituting the rolling setting device 15 as a steel sheet temperature control device will be described below.

The rolling setting device 15 communicates with the upper computer 30. The upper computer 30 includes a target plate thickness setting unit 31 that sets a target plate thickness of the steel plate 6 and a target temperature setting unit 32 that sets a target temperature of the steel plate. The target plate thickness and the target temperature are set based on the specification and required quality of the product. However, the target temperature setting unit 32 may set the target temperature rise amount instead of the target temperature. The temperature rise means a relative temperature to a reference temperature.

The plate thickness setting calculation unit 17 of the rolling setting device 15 receives the target plate thickness from the target plate thickness setting unit 31, and calculates a plate thickness setting value based on the received target plate thickness. When the moving plate thickness is changed, the plate thickness setting calculation section 17 receives the target plate thickness after the plate thickness change from the target plate thickness setting section 31, and the moving plate thickness change calculation section 16 calculates the plate thickness change amount of each stage to which the moving plate thickness is changed. Then, a rolling table is prepared based on the amount of change in the plate thickness on each stage, and the rolling table is transmitted to the rolling mill control device 21. The rolling mill control device 21 controls the operation of each of the stages of the roughing mill 4 and the finishing mill 9 in accordance with the rolling schedule.

further, the sheet thickness setting calculation section 17 transmits the sheet thickness setting value to the induction heating apparatus output calculation section 19. When the moving plate thickness is changed, the moving plate thickness change calculation section 16 performs a tapered portion plate thickness calculation process of calculating the plate thickness of the tapered portion 6a of the steel plate 6 generated in accordance with the moving plate thickness change, and transmits plate thickness information on the plate thickness of the tapered portion 6a to the induction heating device output calculation section 19. The plate thickness information of the taper portion 6a transmitted from the moving plate thickness change calculation unit 16 includes, for example, the position and plate thickness of the start point of the taper portion 6a and the position and plate thickness of the end point of the taper portion 6 a.

The induction heating device output calculation unit 19 receives the target temperature or the target temperature rise amount from the target temperature setting unit 32 and the target plate thickness from the plate thickness setting calculation unit 17. When the moving sheet thickness is changed, the sheet thickness information of the tapered portion 6a is received from the moving sheet thickness change calculation section 16. The induction heating device output calculation unit 19 calculates the output (power) of the induction heating device 7 using a map or a function that defines the relationship between the thickness of the steel sheet 6 and the output of the induction heating device 7 to achieve the target temperature or the target temperature rise amount. When the moving sheet thickness is changed, the output of the induction heating device 7 when the tapered portion 6a passes through the induction heating device 7 is calculated based on the sheet thickness information of the tapered portion 6a received from the moving sheet thickness change calculation section 16. The induction heating device output calculation unit 19 sets the calculated output of the induction heating device 7 to the induction heating device control device 22.

In each of the embodiments described below, details of the induction heating apparatus output calculation process executed by the induction heating apparatus output calculation unit 19 will be described.

3. Output calculation processing for induction heating device according to embodiment 1

Fig. 4 is a diagram illustrating an output calculation process of an induction heating apparatus according to embodiment 1 of the present invention. In the upper graph of fig. 4, a change with time of the sheet thickness h at a predetermined position in the induction heating apparatus 7 when the tapered portion 6a of the steel sheet 6 passes through the induction heating apparatus 7 is described, and in the lower graph, a change with time of the output p of the induction heating apparatus 7 is described.

In the example shown in fig. 4, the thickness h of the plate at a predetermined position in the induction heating device 7 is set to be h₀Change is h₁. The thinner the plate thickness h is, the smaller the output p of the induction heating device 7 that can achieve the target temperature or the target temperature rise amount is. In the example shown in FIG. 4, the plate thickness h before the plate thickness change is shifted₀Corresponding output p₀Moving the plate thickness h after the plate thickness change₁Corresponding output p₁. Corresponding to the time t when the plate thickness h begins to change₀Is the starting point of the tapered portion 6a and stops changing at a time t corresponding to the plate thickness h₁Is the end point of the tapered portion 6 a. The plate thickness h of the tapered portion 6a is from h₀To h₁Continuously changing.

In the output calculation process of the induction heating apparatus of the present embodiment, the plate thickness h based on the starting point of the taper portion 6a₀And the plate thickness h of the end point of the tapered portion 6a₁The output p of the induction heating device 7 at the time when the tapered portion 6a passes through the induction heating device 7 is calculated. Specifically, the plate thickness h from the starting point of the corresponding tapered portion 6a₀Output p of₀Initially, the plate thickness h toward the end point of the corresponding tapered portion 6a₁Output p of₁The output p of the induction heating device 7 is continuously changed at a constant speed. Further, there is a response delay from the time when the output of the induction heating device 7 is changed to the time when the temperature of the steel sheet 6 changes. The start timing of changing the output of the induction heating device 7 is determined based on the running position of the tapered portion 6a on the production line and the response delay.

4. Output calculation processing for induction heating device according to embodiment 2

Fig. 5 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 2 of the present invention. The upper graph of fig. 5 shows the change with time of the sheet thickness h at a predetermined position in the induction heating device 7 when the tapered portion 6a of the steel sheet 6 passes through the induction heating device 7, and the lower graph shows the change with time of the output p of the induction heating device 7.

In the example shown in fig. 5, the plate thickness h at a predetermined position in the induction heating device 7 is set to be from h, as in the example shown in fig. 4₀To h₁Continuously changing. In the output calculation process of the induction heating apparatus of the present embodiment, the plate thickness h excluding the starting point of the taper portion 6a₀And the plate thickness h of the end point of the tapered portion 6a₁The output p of the induction heating device 7 at the time when the tapered portion 6a passes through the induction heating device 7 is also calculated based on the plate thicknesses set at a plurality of intermediate target points in the rolling direction of the tapered portion 6 a.

The intermediate target point corresponds to the start time t from the conical portion 6a₀To the end time t₁At any number of times t between_c0，t_c1the location of (1). Calculating the time t of each intermediate target point_c0，t_c1Thickness h of the plate_c0，h_c1The output p of the induction heating device 7 capable of achieving the target temperature or the target temperature rise amount is calculated using the map or the function described above_c0，p_c1. The output p of the induction heating device between the starting point of the tapered portion 6a and the intermediate target point, between the intermediate target points and the end point of the tapered portion 6a is calculated by linear fitting.

5. Induction heating device output calculation processing according to embodiment 3

Fig. 6 and 7 are diagrams for explaining the output calculation processing of the induction heating apparatus according to embodiment 3 of the present invention. In the upper graphs of fig. 6 and 7, a change with time of the plate thickness h at a predetermined position in the induction heating device 7 when the tapered portion 6a of the steel plate 6 passes through the induction heating device 7 is described, and in the lower graphs, a change with time of the output p of the induction heating device 7 is described.

In the examples shown in fig. 6 and 7, the plate thickness h at a predetermined position in the induction heating device 7 is set to be from h, as in the example shown in fig. 4₀To h₁Continuously changing. In the output calculation process of the induction heating apparatus of the present embodiment, the plate thickness h from the starting point of the corresponding tapered portion 6a₀Output p of the induction heating device 7₀Plate thickness h toward the end point of the corresponding tapered portion 6a₁Output p of the induction heating device 7₁The output p of the induction heating device 7 is changed stepwise.

In the example shown in fig. 6, at the start time t of the tapered portion 6a₀The output p of the induction heating device 7 is adjusted from the corresponding plate thickness h₀Output p of₀The change is initiated. Thereafter, the output p of the induction heating device 7 is changed stepwise at the end time t of the tapered portion 6a₁The induction heating device 7 is made to correspond to the plate thickness h₁Output p of₁But may vary. In the example shown in FIG. 7, the plate thickness h corresponding to the starting point of the tapered portion 6a is maintained₀Output p of₀Until a start time t later than the tapered portion 6a₀The time of day. Thereafter, the output p of the induction heating device 7 is changed stepwise earlier than the end time t of the tapered portion 6a₁At the time point (2), the induction heating device 7 is made to correspond to the plate thickness h at the end point of the tapered portion 6a₁output p of₁And (4) changing. The number of stages in which the output p of the induction heating device 7 is changed stepwise is not limited. However, the smaller the number of stages, the more likely the temperature distribution of the tapered portion 6a becomes uneven, and the larger the number of stages is, the better.

6. Output calculation processing for induction heating device according to embodiment 4

Fig. 8 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 3 of the present invention. In embodiment 1, the map or function used for calculating the output of the induction heating device 7 is created on the premise of the planned temperature of the steel sheet 6 (referred to as an entrance-side planned temperature) at the time of entering the induction heating device 7. However, the actual temperature of the steel sheet 6 (referred to as the inlet-side actual temperature) at the time of entering the induction heating device 7 does not necessarily coincide with the inlet-side planned temperature due to factors such as individual differences or changes over time of the equipment, variations in the operating state, and variations in the environmental conditions.

In the induction heating device output calculation process of the present embodiment, the output of the induction heating device 7 is controlled using the inlet-side actual temperature during online work. Specifically, the inlet-side actual temperature T of the steel sheet 6 is collected from the rough outlet-side thermometer 5 provided on the upstream side of the induction heating device 7^AFComparing the inlet side actual temperature T^AFAnd inlet side planned temperature T^CAL. Then, based on the inlet side actual temperature T^AFAnd inlet side planned temperature T^CALThe deviation therebetween, the correction output Δ p of the induction heating device 7 is calculated_FF. Corrected output Δ p_FFAt the inlet side actual temperature T^AFSpecific inlet side planned temperature T^CALhigher is set to a negative value, and the actual temperature T on the inlet side^AFSpecific inlet side planned temperature T^CALLow is set to a positive value. By outputting the corrected output Δ p_FFThe output p of the induction heating device 7 in the setting calculation is added to obtain the final output.

in the present embodiment, the inlet-side actual temperature is collected from the rough outlet-side thermometer 5, but if the temperature control of the steel sheet is performed with the target temperature rise amount, the inlet-side actual temperature rise amount may be collected instead of the inlet-side actual temperature. In this case, the inlet-side planned temperature rise amount and the inlet-side actual historical temperature rise amount are compared, and the correction output of the induction heating device 7 may be calculated in accordance with the deviation.

7. Output calculation processing for induction heating device according to embodiment 5

Fig. 9 is a diagram for explaining an output calculation process of an induction heating apparatus according to embodiment 5 of the present invention. In embodiment 1, the map or function used for calculating the output of the induction heating device 7 is created such that the temperature of the steel sheet 6 after passing through the induction heating device 7 becomes the target temperature. However, the actual temperature of the steel sheet 6 after passing through the induction heating device 7 (referred to as the outlet-side actual temperature) does not necessarily match the target temperature due to factors such as individual differences or changes over time of the apparatus, variations in the working state, and variations in the environmental conditions.

In the induction heating device output calculation process of the present embodiment, the output of the induction heating device 7 is controlled using the outlet-side actual temperature during the inline work. Specifically, the outlet-side actual temperature T of the steel sheet 6 is collected from a finishing mill inlet-side thermometer 8 provided on the downstream side of the induction heating device 7^ACTComparing the target temperature T^TGTAnd the actual temperature T of the outlet side^ACT. Then, based on the target temperature T^TGTAnd the actual temperature T of the outlet side^ACTThe deviation therebetween, the correction output Δ p of the induction heating device 7 is calculated_FB. Corrected output Δ p_FBAt the outlet side the actual temperature T^ACTSpecific target temperature T^TGTSet to a negative value in the higher case, and the actual temperature T at the outlet side^ACTSpecific target temperature T^TGTLow is set to a positive value. Corrected output Δ p_FBThe final output is obtained by adding the calculated output p of the induction heating device 7 to the setting.

In the present embodiment, the outlet-side actual temperature is collected from the finish rolling mill inlet-side thermometer 8, but if the temperature control of the steel sheet is performed with the target temperature rise amount, the outlet-side actual temperature rise amount may be collected instead of the outlet-side actual temperature. In this case, the actual historical temperature rise on the inlet side and the target temperature rise may be compared, and the correction output of the induction heating device 7 may be calculated in accordance with the deviation.

8. Others