JP6477400B2 - Strip temperature estimation apparatus and strip temperature estimation method for annealing furnace - Google Patents

Description

  The present invention relates to a strip temperature estimation device and a strip temperature estimation method for an annealing furnace. In particular, in an annealing furnace, the temperature of a metal steel strip (hereinafter referred to as a strip) is estimated without using a temperature sensor such as a thermocouple, a resistance temperature detector, and a radiation thermometer, and a temperature measurement auxiliary device. The present invention relates to a strip temperature estimation device and a strip temperature estimation method.

  As shown in FIG. 9, the annealing furnace includes a heating furnace HF for heating the strip, a soaking furnace SF for keeping the temperature constant, and a cooling furnace CF for cooling. By passing the strip through the annealing furnace at a desired time, heat treatment for the purpose of adjusting the physical property value, crystal structure, etc. of the strip is performed. For this reason, the strip temperature is measured, and feedback control of the heating furnace temperature based on the result is performed. Conventionally, as a sensor for measuring a strip temperature, it is known to install a thermocouple, a resistance temperature detector, or a radiation thermometer in a furnace and measure the temperature with or without contact with the strip. .

  As a contact-type temperature measuring method, there is a method in which a thermocouple or a resistance temperature detector is brought into contact with a strip for measurement. However, the method of measuring the strip temperature by contacting a thermocouple or resistance temperature detector is subject to scratches on the strip surface, the contact portion is easily damaged, and is inferior in durability. It becomes a problem to occur. Therefore, the method of measuring the temperature by bringing a thermocouple or a resistance temperature detector into contact with the strip is limited to applications such as temporary temperature confirmation.

  In order to measure the strip surface temperature in a non-contact manner using a thermocouple or a resistance temperature detector, the ambient temperature in the vicinity of the temperature sensor and the strip surface temperature must be equal. Therefore, in Japanese Patent Application Laid-Open No. 2009-145255 (Patent Document 1), a reflection member for reflecting radiant heat transfer from a strip is installed so as to face the strip, and is formed between the strip and the reflection member. A method of replacing the strip surface temperature by measuring the temperature of a space close to a soaking state has been proposed.

  Another method for measuring the temperature without contact includes a method using a radiation thermometer. However, in the method using a radiation thermometer, measurement noise (hereinafter referred to as background noise) due to radiation generated from a furnace wall or the like other than the strip to be temperature-measured, or changes in the surface state such as oxidation of the strip surface The change in emissivity associated with this hinders accurate temperature measurement.

  In recent years, in particular, the demand for high value-added steel sheets such as high-tensile steel and electromagnetic steel sheets is increasing by controlling the physical property values and crystal structures of materials with high precision by alloying and heat treatment. However, high-value-added steel sheets realized by alloying make the measurement of strip temperature with a radiation thermometer more difficult because the emissivity varies depending on the alloy composition.

  Therefore, in the non-contact temperature measurement using the radiation thermometer, it is necessary to remove the influence of the change in the radiation rate due to the background noise, the change in the surface state, and the change in the alloy composition.

  For example, in Japanese Patent Application Laid-Open No. 2014-130074 (Patent Document 2), in a radiation thermometer installed in the center of a concave cavity and a cavity concave portion, the temperature of the cavity inner wall is controlled to make the radiation rate constant, and multiple reflection is performed on the cavity inner wall. Thus, a temperature measurement method for setting the effective emissivity to 1 has been proposed. Further, by controlling the temperature of the cavity inner wall by feedback control of the distance between the cavity opening and the strip, it is possible to reduce the influence of background noise that enters the cavity as the strip vibrates.

  In JP-A-2005-233790 (Patent Document 3), radiation reflected by the wedge between the strip and the roll, radiation emitted by the roll, and radiation emitted by the strip are measured by different radiation thermometers. A method of calculating the strip temperature from the measured value and calculating the strip temperature based on the calculation result and the measured value of the radiation emitted from the strip has been proposed.

JP 2009-145255 A JP 2014-130074 A JP 2005-233790 A

  In the non-contact temperature measurement method described above, it is necessary to use a plurality of temperature sensors or to install a temperature measurement auxiliary tool such as a reflecting member or a cavity in addition to the temperature sensor in order to measure a certain temperature. .

  Further, strictly speaking, the method of measuring using a radiation thermometer merely measures the surface temperature of the strip, and cannot measure the temperature inside the strip.

  In addition, in order to control the metal crystal structure with high accuracy in the annealing furnace, it is required to control the heating and cooling rates at the time of heating and cooling to desired values in addition to the temperature. That is, it is required to measure the temperature gradient of the strip from the heating furnace to the cooling furnace, so that the strip temperature can be measured throughout the annealing furnace. It is necessary to arrange a large number of strip thermometers.

  The present invention has been made to solve the above-described problems, and an annealing furnace that can estimate the average temperature of each strand of a strip in an annealing furnace without using a temperature sensor and a temperature measuring auxiliary tool. An object of the present invention is to provide a strip temperature estimation device and a strip temperature estimation method.

  In order to achieve the above object, a strip temperature estimation device according to the present invention is configured as follows.

  The strip temperature estimation device according to the present invention is a strip temperature estimation device for an annealing furnace that conveys strips alternately placed on a plurality of helper rolls. The annealing furnace includes a motor that individually drives a plurality of helper rolls, and a speed sensor that outputs a signal corresponding to the rotational speed of the motor.

  The strip temperature estimation device includes resonance frequency measurement means, Young's modulus estimation means, and strand temperature estimation means. The resonance frequency measuring means measures the resonance frequency of a portion that contributes to the strip tension in the torque generated by the motor, based on the output signal of the speed sensor. The Young's modulus estimator estimates the Young's modulus of the strand that is a part of the strip that is spanned between the plurality of helper rolls based on the resonance frequency. The strand temperature estimation means estimates the average temperature of the strands based on the Young's modulus estimated by the Young's modulus estimation means.

  In one preferred embodiment, the strip temperature estimation device stores in advance a parameter table that defines the relationship between the Young's modulus and the strip temperature for each steel material of the strip. In addition, the strand temperature estimation means estimates the average temperature of the strands by obtaining the strip temperature corresponding to the Young's modulus estimated by the Young's modulus estimation means from the parameter table.

  In another preferred embodiment, the annealing furnace includes a tensiometer, an out-of-furnace roll, and a control device. The tensiometer outputs a signal corresponding to the tension of the strip. The out-of-furnace roll is the uppermost stream of the plurality of helper rolls and is provided outside the entrance side of the furnace body. The control device controls the roll outside the furnace based on the output signal of the tensiometer so that the tension of the strand matches a predetermined tension setting value. In addition, the strand temperature estimation means is based on the output signal of the speed sensor, the strip temperature outside the entrance side of the furnace body, the tension set value, and the Young's modulus estimated by the Young's modulus estimation means. Estimate temperature.

  In order to achieve the above object, the strip temperature estimation method according to the present invention is configured as follows.

  The strip temperature estimation method according to the present invention is a strip temperature estimation method for an annealing furnace that conveys strips alternately placed on a plurality of helper rolls. The annealing furnace includes a motor that individually drives a plurality of helper rolls, and a speed sensor that outputs a signal corresponding to the rotational speed of the motor.

  The strip temperature estimation method includes a resonance frequency measurement step, a Young's modulus estimation step, and a strand temperature estimation step. The resonance frequency measurement step measures the resonance frequency of the portion that contributes to the strip tension in the torque generated by the motor based on the output signal of the speed sensor. In the Young's modulus estimation step, the Young's modulus in a strand that is a part of a strip laid between rolls of a plurality of helper rolls is estimated based on the resonance frequency. In the strand temperature estimation step, the average temperature of the strand is estimated based on the Young's modulus estimated by the Young's modulus estimation means.

  In one preferable aspect, the strip temperature estimation method includes a step of preliminarily storing a parameter table that defines the relationship between the Young's modulus and the strip temperature for each steel material of the strip. In addition, the strand temperature estimation step estimates the average temperature of the strands by obtaining the strip temperature corresponding to the Young's modulus estimated by the Young's modulus estimation step from the parameter table.

  In another preferred embodiment, the annealing furnace includes a tensiometer, an out-of-furnace roll, and a control device. The tensiometer outputs a signal corresponding to the tension of the strip. The out-of-furnace roll is the uppermost stream of the plurality of helper rolls and is provided outside the entrance side of the furnace body. The control device controls the roll outside the furnace based on the output signal of the tensiometer so that the tension of the strand matches a predetermined tension setting value. In addition, the strand temperature estimation step is based on the average value of the strand based on the output signal of the speed sensor, the strip temperature outside the entrance side of the furnace body, the tension setting value, and the Young's modulus estimated by the Young's modulus estimation step. Estimate temperature.

  According to the present invention, the average temperature of each strand of the strip in the annealing furnace can be estimated based on the rotational speed of the motor that drives the helper roll without using the temperature sensor and the temperature measurement auxiliary tool.

It is a figure for demonstrating the structure of the annealing furnace which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the structure of the drive device of the arbitrary helper rolls arrange | positioned at the annealing furnace. It is a block diagram for demonstrating the structure of the strip temperature estimation apparatus 10 which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the change of the resonant frequency by the temperature rise of strip STRP. It is a figure which shows an example of the parameter table which concerns on Embodiment 1 of this invention. It is a flowchart of the control routine which the strip temperature estimation apparatus 10 which concerns on Embodiment 1 of this invention performs. It is a block diagram for demonstrating the structure of the strip temperature estimation apparatus 10 which concerns on Embodiment 2 of this invention. It is a flowchart of the control routine which the strip temperature estimation apparatus 10 which concerns on Embodiment 2 of this invention performs. 1 is a diagram for explaining the overall configuration of an annealing furnace 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1
[System Configuration of Embodiment 1]
FIG. 1 is a diagram for explaining a configuration of an annealing furnace according to Embodiment 1 of the present invention. An annealing furnace 1 shown in FIG. 1 is a vertical annealing furnace. The annealing furnace 1 includes a plurality of helper rolls. The strip STRP enters the inside of the furnace body 2 from the left side of FIG. The strip STRP is conveyed in the direction of the arrow VD in the figure in a state where it is wound around a total of N + 1 helper rolls in the upper and lower portions inside the furnace body 2.

The i-th helper roll from the entrance side of the furnace body 2 is referred to as a helper roll HR-i. A part of the strip STRP stretched between the helper roll HR-i and the helper roll HR- (i + 1) is referred to as a strand Si. Moreover, the annealing furnace 1 is provided with an out-furnace roll (helper roll HR-0 located at the most upstream) outside the entrance side of the furnace body 2. A part of the strip STRP stretched between the helper roll HR-0 and the helper roll HR-1 is referred to as a strand S-0. The length of the strand S-0 is referred to as strand length _{L 0.} The strip temperature _{Tstrp_0} in the strand S-0 is _assumed to be equal to room temperature.

  FIG. 2 is a view for explaining the configuration of an optional helper roll driving device arranged in the annealing furnace 1. Since the configuration of each helper role is the same, here, the helper role HR-i will be described. The helper roll HR-i is connected to a motor Mi for driving the helper roll via a gear Gi. The motor control device DR-i drives the motor Mi at a variable speed. The motor control device DR-i includes a speed sensor SS-i that detects the rotational speed of the motor, a current sensor CS-i that measures a current and a voltage applied to the motor Mi, and a voltage sensor VS-i. The motor control device DR-i includes a feedback signal Sfbk-i, Cfbk-i, and Vfbk-i output from the speed sensor SS-i, current sensor CS-i, and voltage sensor VS-i, and a speed reference Sref-i. Based on the above, it is possible to appropriately control the motor Mi so that the relative speed difference between the strip STRP and the helper roll HR-i becomes zero. In addition, the length of each strand in the furnace main body 2 is the same, and is called the strand length L.

  It is assumed that the tension distribution of the strip STRP in the furnace body 2 is appropriately feedback controlled by a tension meter 3 (tension meter) arranged in the line and controlled to a desired tension set value Fi. For example, the tension meter 3 is disposed on the entrance side or the exit side of the furnace body 2, and the motor control device DR-0 of the outside furnace roll (helper roll HR-0) is configured to strip the strip STRP based on the output signal of the tension meter 3. Control the tension.

[Strip Temperature Estimation Device in Embodiment 1]
FIG. 3 is a block diagram for explaining the configuration of strip temperature estimation apparatus 10 according to Embodiment 1 of the present invention. The strip temperature estimation device 10 estimates the average temperature of each strand of the strip STRP conveyed in the furnace body 2. The strip temperature estimation device 10 estimates the average temperature of each strand based on a signal and a fixed parameter output from each speed sensor SS that detects the rotation speed of each motor for driving the helper roll.

  The strip temperature estimation device 10 includes, for example, a memory including a ROM and a RAM, an input / output interface that inputs and outputs various types of information, and a processor that executes various types of arithmetic processing based on various types of information and programs stored in the memory. In the block showing the strip temperature estimation device 10 of FIG. 3, some of various processes executed by the strip temperature estimation device 10 are represented by blocks. The memory stores a program corresponding to each block in advance, and the processor reads and executes the program, thereby realizing processing of each block.

  The strip temperature estimation device 10 executes each process of the resonance frequency measurement means 11, Young's modulus estimation means 12, and strand temperature estimation means 13. The resonance frequency measuring means 11 is a process of measuring the resonance frequency of the portion that contributes to the strip tension in the torque generated by the motor for driving the helper roll, based on the output signal of the speed sensor SS. The Young's modulus estimator 12 is a process for estimating the Young's modulus in the strand that is a part of the strip STRP that is spanned between the rolls of the plurality of helper rolls, based on the resonance frequency. The strand temperature estimating means 13 is a process for estimating the average temperature of the strand based on the Young's modulus estimated by the Young's modulus estimating means 12.

  In the strand S-i, in the traveling direction of the strip STRP, in addition to the transport of the strip STRP, a behavior in which stretching vibration due to elasticity of the strip STRP is superimposed is observed. On the other hand, in order to keep the speed constant at both ends of the strand Si by the helper roll HR-i and the helper roll HR- (i + 1), it is necessary to cancel the vibration component. Therefore, vibration for canceling the expansion and contraction vibration of the strand Si is superimposed on the strip tension applying component TRQi of the motor torque generated by the helper roll HR-i. At this time, the resonance frequency of the vibration superimposed on the torque of the helper roll corresponds to the resonance frequency of the strip stretching vibration in the strand Si, and is proportional to the Young's modulus and density of the strip STRP and the strand length. It is expressed as (1).

ここで、
ω_{ｈｒ＿ｒｅｓ＿ｎ＿ｉ}：ストランドＳ−ｉのｎ次の固有振動数
ω_{ｓｔｒｐ＿ｒｅｓ＿ｎ＿ｉ}：ヘルパーロールＨＲ−ｉ発生トルクの張力付与成分に現れるｎ次の固有振動数
Ｅ_ｉ:ストランドＳ−ｉにおけるヤング率
Ｌ：ストランド長
ρ：ストリップＳＴＲＰの密度
ｎ：自然数

here,
ω _{hr_res_n_i} : n-th order natural frequency of the strand _Si ω _{strp_res_n_i} : n-th order natural frequency appearing in the tension imparting component of the helper roll HR-i generated torque E _i : Young's modulus in the strand _Si L: Strand length ρ: density of strip STRP n: natural number

The natural frequency is the frequency that the object has the most vibration. When the same frequency as the natural frequency of the object is given to the object, the vibration is amplified and strong vibration occurs. This is called resonance, and the frequency is called resonance frequency. The natural frequency of the helper roll changes with increasing or decreasing temperature in the strand in the heating furnace or cooling furnace. FIG. 4 is a diagram for explaining a change in the resonance frequency due to the temperature rise of the strip STRP. In the heating furnace HF (FIG. 9), the temperature of the strip STRP becomes higher toward the downstream (T _{strp — 1} <T _{strp — 2} <T _{strp — 3} <T _{strp — 4} ). As shown in FIG. 4, the peak position of the frequency decreases as the strip temperature increases downstream. The resonance frequency measuring means 11 decomposes the output signal of the speed sensor into frequency components by Fourier transform, searches for the frequency at which the peak position changes, and acquires that frequency as the resonance frequency (FIG. 4).

In a furnace that aims to increase or decrease the strip temperature, such as the heating furnace HF or the cooling furnace CF, the strip temperature gradually increases or decreases in the furnace as shown in FIG. Therefore, the Young's modulus estimating means 12 calculates the average value of the Young's modulus in the strands using the formula (2) for each of the helper rolls HR-1 to HR-N. Note that the resonance frequencies of the respective orders measured by the resonance frequency measuring unit 11 are substituted into ω _{hr_res_n_i} in the equation (2).

ここで、
Ｙ：測定する最大の固有振動数の次数

here,
Y: Order of maximum natural frequency to be measured

  The strip temperature in the strand Si can be estimated by using the relationship between the Young's modulus measured offline and the temperature in addition to the Young's modulus calculated by the equation (2). Specifically, first, the strip temperature estimation device 10 stores in advance a parameter table that defines the relationship between the Young's modulus and the strip temperature for each steel material of the strip. And the strand temperature estimation means 13 estimates the average temperature of a strand by acquiring the strip temperature according to the Young's modulus estimated by the Young's modulus estimation means 12 from a parameter table. FIG. 5 is a diagram illustrating an example of a parameter table. As shown in FIG. 5, the Young's modulus tends to decrease as the temperature increases.

(flowchart)
FIG. 6 is a flowchart of a control routine executed by the strip temperature estimation apparatus 10 according to the first embodiment in order to realize the above-described operation. This control routine is repeatedly executed at predetermined intervals.

  In step S100, the resonance frequency measuring unit 11 decomposes the output signal of the speed sensor into frequency components by Fourier transform, searches for the frequency at which the peak position changes, and acquires the frequency as the resonance frequency.

In step S102, the Young's modulus estimator 12 calculates an average value of Young's modulus in each strand using the equation (2). In addition, the resonance frequency of each order calculated _| required in step S100 is substituted for (omega) _{hr_res_n_i} of Formula (2).

  In step S104, the strand temperature estimation means 13 estimates the average temperature of each strand by obtaining the strip temperature corresponding to the average value of the Young's modulus in each strand from the parameter table described above.

  As described above, according to the routine shown in FIG. 6, the average value of the Young's modulus of the strands can be calculated based on the output signal of the speed sensor (the amount of helper roll state). The average temperature of each strand can be estimated from the relationship (parameter table) between the Young's modulus and the temperature collected offline. That is, according to the system of the first embodiment of the present invention, the strip output from the control output for controlling the helper roll for transporting the strip without installing the temperature sensor or the temperature measurement auxiliary device in the annealing furnace 1 is performed. Can be estimated as the average temperature in each strand.

Embodiment 2
[System Configuration of Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. The system of this embodiment can be realized by causing the strip temperature estimation device 10 to execute the routine of FIG. 8 described later in the configuration shown in FIGS. 1, 2, and 7.

[Strip Temperature Estimation Device in Embodiment 2]
The strip temperature estimation apparatus 10 according to the first embodiment described above estimates the temperature of each strand from the Young's modulus using the relationship (parameter table) between the Young's modulus and temperature collected offline. On the other hand, in the strip temperature estimation device 10 according to the second embodiment, the temperature of each strand is estimated online using the equation (11) described later.

  FIG. 7 is a block diagram for explaining the configuration of strip temperature estimation apparatus 10 according to Embodiment 2 of the present invention. The strip temperature estimation device 10 calculates the average temperature of each strand of the strip STRP conveyed in the furnace body 2. In FIG. 7, the configuration other than the fixed parameter and the strand temperature estimation means 23 is the same as the configuration shown in FIG. The strip temperature estimation device 10 calculates the average temperature of each strand based on a signal and a fixed parameter output from each speed sensor SS that detects the rotation speed of each motor for driving the helper roll.

It is assumed that the strip STRP in the strand Si does not undergo plastic deformation due to stress. In this case, elongation l _i strands S-i, as the sum of the elongation due to thermal expansion and tension is expressed by the following equation.

ここで、
ｌ_{ｈｅｌ＿ｉ}：ストランドＳ−ｉにおける熱伸び
ｌｓｔｆ＿ｉ：ストランドＳ−ｉにおける張力による伸び

here,
l _hel — i: thermal elongation in the strand S i, lstf — i: elongation due to the tension in the strand S i

ここで、
α_ｈｅｌ：熱膨張率
Ｌ：ストランド長
Ｔ_{ｓｔｒｐ＿ｉ}：ストランドＳ−ｉにおけるストリップ温度
Ｔ_{ｓｔｒｐ＿ｉ−１}：ストランドＳ−（ｉ−１）におけるストリップ温度

here,
alpha _hel: thermal expansion coefficient L: Strand length _T strp_i: Strand S-i strip temperature at _{T strp_i-1:} strip temperature in strand S- (i-1)

ここで、
Ｆ_ｉ：ストランドＳ−ｉにおけるストリップ張力設定値
Ｌ：ストランド長
Ａ：ストリップ断面積
ｖ_ｉ：ｉ番目のヘルパーロールにおけるロール周速
Ｅ_ｉ:ストランドＳ−ｉにおけるヤング率

here,
F _i : Strip tension set value in the strand Si L: Strand length A: Strip cross-sectional area v _i : Roll peripheral speed in the i-th helper roll E _i : Young's modulus in the strand Si

The extension of the strip in the strand S-i is expressed by the following equation using the peripheral speeds v _hr — i and v _hr — i _{+ 1} . The circumferential speeds v _hr — i and v _hr — i + 1 can be calculated from the motor rotational angular velocity ω _hr measured by the speed sensor installed in the helper roll driving motor in the helper rolls HR-i and HR- (i + 1) at both ends of the strand.

ここで、
Δｔ：測定時間
ｖ_ｈｒ＿ｉ：ｉ番目のヘルパーロールの周速度

here,
Δt: measurement time v _{hr —} i: peripheral speed of the i-th helper roll

ここで、
ｒ_ｈｒ＿ｉ：ｉ番目のヘルパーロールのロール半径
Ｋ_ｈｒ＿ｉ：ｉ番目のヘルパーロールおよび駆動用モータ間のギア比
ω_ｈｒ＿ｉ：ｉ番目のヘルパーロール駆動用モータの回転角速度

here,
r _{hr —} i: roll radius of the i-th helper roll K _{hr —} i: gear ratio between the i-th helper roll and the drive motor ω _{hr —} i: rotational angular velocity of the i-th helper roll drive motor

  With respect to Expression (3), the total sum from i = 0 to i = i is expressed as the following expression from Expression (4), Expression (5), and Expression (6).

  The relationship of Formula (3) and the average temperature in the i-th strand from Formula (8), Formula (9), and Formula (10) can be expressed as Formula (11).

As shown in the equation (11), the strip temperature _{Tstrp_i} in the i-th strand is the known zeroth strip temperature _{Tstrp_0} , the tension reference F _i , the Young's modulus E _i calculated by the equation (2), and the equation (7) can be calculated on the basis of the helper roll peripheral velocity v ₀ and v _i obtained from the velocity feedback amount of helper roll drive motor which is calculated by. T _{strp_1} can be calculated by substituting 1 for i.

(flowchart)
FIG. 8 is a flowchart of a control routine executed by the strip temperature estimation apparatus 10 according to the second embodiment in order to realize the above-described operation. This routine is the same as the routine shown in FIG. 6 except that the process of step S104 is replaced with step S204. Hereinafter, in FIG. 8, the same steps as those shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. This control routine is repeatedly executed at predetermined intervals.

  After the process of step S102, in step S204, the strand temperature estimation means 23 uses the above-described equation (11), the output signal of the speed sensor, the strip temperature (room temperature) outside the entrance side of the furnace body, and the tension setting. Based on the value and the average value of the Young's modulus calculated in step S102, the average temperature of the strand is calculated.

  As described above, according to the routine shown in FIG. 8, the average value of the Young's modulus of the strands can be calculated based on the output signal of the speed sensor (helper roll state quantity). Then, the temperature of each strand can be calculated online using Equation (11). That is, according to the system of the first embodiment of the present invention, the strip output from the control output for controlling the helper roll for transporting the strip without installing the temperature sensor or the temperature measurement auxiliary device in the annealing furnace 1 is performed. Can be estimated as the average temperature in each strand.

DESCRIPTION OF SYMBOLS 1 Annealing furnace 2 Furnace main body 3 Tension meter 10 Strip temperature estimation apparatus 11 Resonance frequency measurement means 12 Young's modulus estimation means 13 Strand temperature estimation means STRP Strip Si i-th strand HR-i i-th helper roll VD Progress of strip Direction G-i Gear between the i-th helper roll and the motor for driving the helper roll M-i Motor for driving the i-th helper roll SS-i Speed sensor VS-i i for the motor for driving the i-th helper roll Applied voltage sensor CS-i of the i th helper roll driving motor Current sensor Sfbk-i i th helper roll driving motor speed feedback signal Vfbk-i i th helper roll driving voltage sensor CS-i Voltage feedback signal Cfbk-i i for roll driving motor Current feedback signal DR-i of the motor for driving the helper roll of the eye i-th helper roll motor controller Sref-i Speed reference signal HF of the motor for driving the i-th helper roll HF Heating furnace SF Soaking furnace CF Cooling furnace

Claims (8)

A strip temperature estimation device for an annealing furnace that conveys strips alternately placed on a plurality of helper rolls,
The annealing furnace is
A motor for individually driving the plurality of helper rolls;
A speed sensor that outputs a signal corresponding to the rotational speed of the motor,
The strip temperature estimation device includes:
The output signal of the speed sensor is decomposed into frequency components by Fourier transform, the frequency at which the peak position changes is searched, and the resonance of the portion of each torque that contributes to the strip tension among the torque generated by the motor. Resonance frequency measuring means for measuring as a frequency;
A Young's modulus estimator for estimating a Young's modulus in a strand that is part of the strip that is spanned between rolls of the plurality of helper rolls, based on the resonance frequency of each order ;
Based on the Young's modulus estimated by the Young's modulus estimating means, a strand temperature estimating means for estimating an average temperature of the strands;
An apparatus for estimating the strip temperature of an annealing furnace. The Young's modulus estimation means has the following relationship when a part of the strip spanned between the i-th helper roll and the (i + 1) -th helper roll among the plurality of helper rolls is the i-th strand. The apparatus for estimating a strip temperature of an annealing furnace according to claim 1, wherein the Young's modulus E _i in the i-th strand is estimated using an equation.

here,
ω _{hr_res_n_i} is the n-th resonance frequency that appears in the strip tension applying component of the torque generated in the i-th helper roll,
L is the strand length,
ρ is the density of the strip,
Y is the order of the maximum resonance frequency to be measured,
n is a natural number. For each steel strip material, a parameter table that defines the relationship between Young's modulus and strip temperature is stored in advance.
The strand temperature estimation means estimates the average temperature of the strands by obtaining a strip temperature corresponding to the Young's modulus estimated by the Young's modulus estimation means from the parameter table.
The strip temperature estimation apparatus for an annealing furnace according to claim 1 or 2, characterized in that: The annealing furnace is
A tensiometer that outputs a signal corresponding to the tension of the strip;
An outer roll provided at the outermost entrance side of the furnace body, which is the uppermost stream of the plurality of helper rolls;
A controller for controlling the outer roll so that the tension of the strand matches a predetermined tension setting value based on the output signal of the tensiometer,
The strand temperature estimation means is based on the output signal of the speed sensor, the strip temperature outside the entrance side of the furnace body, the tension setting value, and the Young's modulus estimated by the Young's modulus estimation means. Estimating the average temperature of the strands,
The strip temperature estimation apparatus for an annealing furnace according to claim 1 or 2, characterized in that: The strand temperature estimation means includes
Among the plurality of helper rolls, a part of the strip spanned between the i-th helper roll and the (i + 1) -th helper roll is an i-th strand,
The outside roll is the 0th helper roll,
When a part of the strip spanned between the 0th helper roll and the 1st helper roll is the 0th strand,
The strip temperature estimation device for an annealing furnace according to claim 4, wherein the strip temperature _{Tstrp_i} of the i-th strand is estimated using the following relational expression.

here,
T _{strp_1} is the strip temperature of the first strand,
T _{strp —} 0 is the strip temperature (room temperature) of the 0th strand,
L ₀ is the strand length of the 0th strand,
L is the length of each strand after the first strand,
α _hel is the coefficient of thermal expansion,
Δt is the measurement time,
A is the strip cross-sectional area,
F _i is the strip tension set value at the i-th strand,
v _i is the roll peripheral speed in the i-th helper roll,
E _i is the Young's modulus in the i-th strand. A strip temperature estimation method for an annealing furnace that conveys strips alternately placed on a plurality of helper rolls,
The annealing furnace is
A motor for individually driving the plurality of helper rolls;
A speed sensor that outputs a signal corresponding to the rotational speed of the motor,
The strip temperature estimation method includes:
The output signal of the speed sensor is decomposed into frequency components by Fourier transform, the frequency at which the peak position changes is searched, and the resonance of the portion of each torque that contributes to the strip tension among the torque generated by the motor. A resonance frequency measurement process for measuring as a frequency;
A Young's modulus estimation step of estimating a Young's modulus in a strand that is a part of the strip that is spanned between rolls of the plurality of helper rolls based on the resonance frequency of each order ;
Based on the Young's modulus estimated in the Young's modulus estimation step, a strand temperature estimation step for estimating the temperature of the strand;
A strip temperature estimation method for an annealing furnace, comprising:

For each steel member of the strip, a step of storing in advance a parameter table that defines the relationship between the Young's modulus and the strip temperature,
The strand temperature estimation step estimates the average temperature of the strand by obtaining the strip temperature corresponding to the Young's modulus estimated by the Young's modulus estimation step from the parameter table,
The strip temperature estimation method for an annealing furnace according to claim 6. The annealing furnace is
A tensiometer that outputs a signal corresponding to the tension of the strip;
An outer roll provided at the outermost entrance side of the furnace body, which is the uppermost stream of the plurality of helper rolls;
A controller for controlling the outer roll so that the tension of the strand matches a predetermined tension setting value based on the output signal of the tensiometer,
The strand temperature estimation step is based on the output signal of the speed sensor, the strip temperature outside the entrance side of the furnace body, the tension setting value, and the Young's modulus estimated by the Young's modulus estimation step. Estimating the average temperature of the strands,
The strip temperature estimation method for an annealing furnace according to claim 6.

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