JP2009228057A - System, method and program for controlling sheet temperature in continuous heat-treatment furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a sheet temperature according to dispersion of the sheet temperature in the longitudinal direction of the steel sheet. <P>SOLUTION: The sheet temperature control system, in a continuous heat-treatment furnace for feed-back controlling the temperature of the belt-state steel sheet for applying the heat-treatment in the continuous heat-treatment furnace 200 is provided with: a control gain-database (DB)104, in which before process information X<SB>1</SB>-X<SB>m</SB>of the continuous heat-treatment furnace 200, ranges of n pieces of the targeted sheet temperatures TS<SB>s</SB>at the furnace outlet side and feedback (FB) control gain, are stored while relating to each other; an FB controller 103, in which the FB control to the continuous heat-treatment furnace 200, is applied based on the FB control gain read from the control gain DB 104 according to the before process information and the targeted sheet temperature at the furnace outlet side; and a control gain calculation part 101, in which the FB control gain stored in the control gain DB 104 is updated according to the dispersion σ<SB>a</SB>of the actual sheet temperatures by obtaining the dispersion σ<SB>a</SB>of the actual sheet temperatures in the longitudinal direction of the steel sheet based on the actual sheet temperature TS<SB>a</SB>(i) at the furnace outlet side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plate temperature control system, method, and program in a continuous heat treatment furnace that controls the plate temperature of a strip-shaped steel plate heat-treated in a continuous heat treatment furnace in a continuous annealing factory, a continuous hot dip galvanizing factory, or the like of an ironworks.

  For example, in a continuous annealing plant of a steel mill, a steel sheet (strip) after cold rolling is sent to an annealing process and annealed. In the annealing step, for example, as shown in FIG. 4, the steel plate 1 is inserted into the direct fire heating zone L by the drive roll 2 and heated directly. Subsequently, after being indirectly heated through the indirect heating zone M, it is cooled through the cooling zone N. In the direct heating zone L, the combustion gas and air are blown out from the combustion burner 4 to directly heat the steel plate 1 by direct fire combustion, and in the indirect heating zone M, the steel plate 1 is indirectly heated by the radiant tube 5. Thermometers 6 and 7 are arranged on the exit side of the direct fire heating zone L and the exit side of the indirect heating zone M, respectively, and measure the actual plate temperature.

  Regarding a plate temperature control method in this type of continuous heat treatment furnace, for example, Patent Documents 1 and 2 disclose a method of predicting a plate temperature on the furnace exit side using a model formula and determining an operation amount.

JP-A-1-259131 JP 7-278682 A

  By the way, in the continuous heat treatment furnace, when the target plate temperature on the outlet side of the furnace side is changed (near the center of the steel plate) when the pretreatment process (referred to as the previous step) or the target plate temperature on the outlet side of the continuous heat treatment furnace changes. The degree of variation in the plate temperature in the longitudinal direction differs.

  In the prior art, the plate temperature control according to the variation in the plate temperature in the longitudinal direction of the steel plate is not performed. Even the methods disclosed in the above-described Patent Documents 1 and 2 do not have a function of correcting a model formula accompanying fluctuations in plate temperature variation in the longitudinal direction of the steel plate.

  This invention is made | formed in view of the above points, and it aims at enabling plate | board temperature control according to the dispersion | variation in the plate | board temperature in the longitudinal direction of a steel plate.

The plate temperature control system in the continuous heat treatment furnace of the present invention is a plate temperature control system in a continuous heat treatment furnace that feedback-controls the plate temperature of a strip-shaped steel plate that is heat-treated in the continuous heat treatment furnace, and includes pre-process information of the continuous heat treatment, Feedback control information storage means for associating and storing the target plate temperature on the furnace exit side and feedback control information, and feedback read from the feedback control information storage means according to the previous process information and the target plate temperature on the furnace exit side Based on the control information, feedback control means for executing feedback control for the continuous heat treatment furnace, and obtaining plate temperature variation information in the longitudinal direction of the steel plate based on the actual plate temperature on the furnace exit side, the plate temperature variation information In response, an update procedure for updating the feedback control information stored in the feedback control information storage means. Characterized by comprising and.
The plate temperature control method in the continuous heat treatment furnace of the present invention is a plate temperature control method in a continuous heat treatment furnace that feedback-controls the plate temperature of a strip-shaped steel plate heat-treated in the continuous heat treatment furnace, and includes information on the previous process of the continuous heat treatment furnace and From the feedback control information storage means for storing the target plate temperature on the furnace exit side and the feedback control information in association with each other, based on the feedback control information read according to the previous process information and the target plate temperature on the furnace exit side, Based on the procedure for executing feedback control for the continuous heat treatment furnace and the actual sheet temperature on the furnace exit side, plate temperature variation information in the longitudinal direction of the steel plate is obtained, and the feedback control information storage is performed according to the plate temperature variation information And a procedure for updating the feedback control information stored in the means.
The program of the present invention is a program for feedback control of the plate temperature of a strip-shaped steel plate heat-treated in a continuous heat treatment furnace, and includes information on the previous process of the continuous heat treatment furnace, a target plate temperature on the furnace exit side, and feedback control. Processing for performing feedback control on the continuous heat treatment furnace based on the feedback control information read according to the previous process information and the target plate temperature on the furnace exit side from the feedback control information storage means for storing the information in association with each other The plate temperature variation information in the longitudinal direction of the steel plate is obtained based on the actual plate temperature on the furnace exit side, and the feedback control information stored in the feedback control information storage means is updated according to the plate temperature variation information. Causes the computer to execute the process.

  According to the present invention, the plate temperature variation information in the longitudinal direction of the steel plate is obtained based on the actual plate temperature on the furnace exit side, and the feedback control stored in the feedback control information storage means according to the plate temperature variation information. Since the information is updated, it is possible to control the plate temperature according to the variation in the plate temperature in the longitudinal direction of the steel plate, and the plate temperature control accuracy is improved.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
In FIG. 1, it is a figure which shows schematic structure of the plate temperature control system in the continuous heat processing furnace of this embodiment. The plate temperature control system in the continuous heat treatment furnace of the present embodiment controls the plate temperature of a strip-shaped steel plate (not shown) to be heat treated in the continuous heat treatment furnace 200, and includes a control gain calculation unit 101, feed forward (FF). A controller 102 and a feedback (FB) controller 103 are provided.

  Further, a control gain database (DB) 104, a constant DB 105, a process performance DB 106, and a manufacturing instruction DB 107 are provided. In FIG. 1, for convenience, the DBs are illustrated by function, but the number is not limited.

The control gain DB 104 stores an FF control gain FF _gain [−] for FF control by the FF controller 102 and an FB control gain FB _gain [−] for FB control by the FB controller 103. Regarding the FB control gain FB _gain , in the control gain DB 104, as shown in FIG. 3, according to the FB control gain table, the previous process information X _{1 to} X _m [−], the target plate temperature TS _s [° C. on the furnace exit side. ] In the n regions (α _k (k = 1, 2,..., N−1) is a target plate temperature threshold [° C.]) and FB control gain FB _gain (m, n). ing. Pre-process the information X _1, ···, X _m is information indicating the type of the previous step of heat treatment in a continuous heat treatment furnace, pickling and cold-rolling process and the like if the previous step annealing process. Moreover, even if it is the same pickling process, you may handle as a mutually different previous process depending on the processing content. In the present embodiment, the FB control gain FB _gain corresponds to the feedback control information referred to in the present invention, and the control gain DB 104 functions as feedback control information storage means referred to in the present invention.

The constant DB 105 stores initial data such as a target plate temperature variation σ _T [° C.], an operation amount change amount limit value DNC [−] (constant), an adjustment parameter K [−] (constant), and the like. For example, the target plate temperature variation σ _T is set in advance to a value that corresponds to the plate temperature variation in the longitudinal direction of the steel plate (passing plate direction) that is acceptable for each coil to be controlled.

The process performance DB 106 stores all the actual data for each FB control cycle for the control target coil, specifically, the actual plate temperature TS _a (i) [° C.] on the furnace exit side, the actual operation amount u output by the FB controller 103. (i) Store [−] (i = 1, 2,..., N).

The manufacturing command DB 107 stores manufacturing command data such as a plate width, a plate thickness, a target plate temperature TS _s on the furnace exit side, and preprocess information X _{1 to} X _m for the control target coil.

The control gain calculation unit 101 reads the FF control gain FF _gain and the FB control gain FB _gain from the control gain DB 104, outputs the FF control gain FF _gain to the FF controller 102, and outputs the FB control gain FB _gain to the FB controller 103. . Regarding the FB control gain FB _gain , for example, when the previous process information acquired from the manufacturing instruction DB 107 is X ₁ and the target plate temperature on the furnace exit side is α ₁ ≦ TS _s <α ₂ , as shown in FIG. The FB control gain FB _gain (1, 2) is read from the control gain DB 104 (FB control gain table).

Although details will be described later, the control gain calculation unit 101 obtains the actual sheet temperature variation σ _a [° C.] in the longitudinal direction of the steel sheet based on the actual sheet temperature TS _a (i) on the furnace exit side, and the results The FB control gain FB _gain stored in the control gain DB 104 is updated in real time according to the plate temperature variation σ _a . In other words, in the present embodiment, the control gain calculation unit 101 functions as an updating unit referred to in the present invention.

The FF controller 102 determines an operation amount for the continuous heat treatment furnace 200 based on the FF control gain FF _gain received from the control gain calculation unit 101, and executes FF control. The FF controller 102 receives welding point passage information on the furnace entry side and exit side and speed change information on the line speed, and conditions such as welding point passage (coil change) and speed change on the furnace entry side and exit side. FF control is executed when there is a change.

The FB controller 103 determines an operation amount for the continuous heat treatment furnace 200 based on the FB control gain FB _gain received from the control gain calculation unit 101, and executes FB control. That is, in this embodiment, the FB controller 103 functions as a feedback control means in the present invention. The FB controller 103 executes FB control at regular intervals.

  FIG. 2 is a flowchart showing the update processing of the FB control gain in the plate temperature control system in the continuous heat treatment furnace of the present embodiment. The update process shown in the flowchart of FIG. 2 is executed by the control gain calculation unit 101 at the FB control timing (fixed period).

First, in step S101, initial data such as a target plate temperature variation σ _T , an operation amount change amount limit value DNC, an adjustment parameter K, and the like are read from the constant DB 105. Here, step S101 is described in the flowchart of FIG. 2 that is executed at regular intervals, but the initial data that has been read once is retained, and the process of step S101 is performed only when the initial data is changed. May be executed.

In step S102, the FB control gain FB _gain is read from the control gain DB 104 based on the pre-process information X _{1 to} X _m for the control target coil acquired from the manufacturing instruction DB 107 and the target plate temperature TS _s on the furnace exit side. For example, when the previous process information acquired from the manufacturing instruction DB 107 is X ₁ and the target plate temperature on the furnace exit side is α ₁ ≦ TS _s <α ₂ , as shown in FIG. 3, the control gain DB 104 (FB control gain table) The FB control gain FB _gain (1, 2) is read from.

Next, in step S103, all the actual data for each FB control cycle for the control target coil, specifically, the actual plate temperature TS _a (i) on the furnace exit side, and the FB controller 103 are output from the process actual DB 106. The actual operation amount u (i) is read (i = 1, 2,..., N).

Next, in step S104, the actual sheet temperature variation σ _a in the longitudinal direction of the steel sheet for the control target coil is reduced based on the furnace-side actual sheet temperature TS _a (i) read in step S103. Calculation is performed according to equation (1). This step S104 is a processing example as the plate temperature variation information calculating means in the present invention.
σ _a = sqrt (Σ (TS _ave −TS _a (i)) ² / N) (1)
TS _ave = ΣTS _a (i) / N

Next, in step S105, it is determined whether the actual plate temperature variation σ _a calculated in step S104 exceeds the target plate temperature variation σ _T read in step S101. This step S105 is a processing example as a comparison means in the present invention.

If σ _a > σ _T in step S105, the process proceeds to step S106 on the assumption that the temperature variation in the longitudinal direction of the steel sheet is greater than or equal to the required target value, and the new FB control gain FB _{gain new} is decreased. Calculation is performed according to equation (2).
FB _{gain new} = FB _{gain old} −ln (σ _a / σ _T ) * ((Δu−DNC) / DNC) * K (2)
Δu = u (i) −u (i−1)

Here, in the right side of the equation (2), ln (σ _a / σ _T ) is a plate temperature fluctuation influence coefficient representing the effect of plate temperature variation in the longitudinal direction of the steel plate, and (Δu−DNC) / DNC is an operation. This is a manipulated variable fluctuation influence coefficient representing the influence of the quantity fluctuation.

Thereafter, in step S107, the FB control gain FB _{gain old} stored in the control gain DB 104 is updated using the _new FB control gain FB _{gain new} calculated in step S106.

On the other hand, if σ _a > σ _{T is} not satisfied in step S105, the FB control gain FB _{gain old} stored in the control gain DB 104 is not updated, and this processing ends. That is, the previously set FB control gain FB _{gain old} is continuously used.

As described above, the actual sheet temperature variation σ _a in the longitudinal direction of the steel sheet is obtained based on the actual sheet temperature TS _a (i) on the furnace exit side, and the control gain DB 104 is determined according to the actual sheet temperature variation σ _a. Since the FB control gain FB _{gain old} stored in is updated, it is possible to dynamically control the plate temperature according to the variation in the plate temperature in the longitudinal direction of the steel plate according to the furnace shape.

  Note that the control gain calculation unit 101, the FF controller 102, and the FB controller 103 can be specifically realized by a computer device including a CPU and various memories, and may be configured by a single device or a plurality of devices. It may be constituted by.

  The object of the present invention can also be achieved by supplying a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus. In this case, the computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

It is a figure which shows schematic structure of the plate | board temperature control system in the continuous heat processing furnace of this embodiment. It is a flowchart which shows the update process of the FB control gain in the plate | board temperature control system in the continuous heat processing furnace of this embodiment. It is a figure for demonstrating the content of the control gain database. It is a figure for demonstrating the example of an annealing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Control gain calculation part 102 Feedforward controller 103 Feedback controller 104 Control gain database 105 Constant database 106 Process performance database 107 Manufacturing command database 200 Continuous heat treatment furnace

Claims (5)

A plate temperature control system in a continuous heat treatment furnace for feedback control of the plate temperature of a strip-shaped steel plate heat-treated in a continuous heat treatment furnace,
Feedback control information storage means for storing the pre-process information of continuous heat treatment, the target plate temperature on the furnace exit side, and feedback control information in association with each other;
Feedback control means for performing feedback control on the continuous heat treatment furnace based on feedback control information read from the feedback control information storage means according to the previous process information and the target plate temperature on the furnace exit side;
Update to obtain the plate temperature variation information in the longitudinal direction of the steel plate based on the actual plate temperature on the furnace exit side, and update the feedback control information stored in the feedback control information storage means according to the plate temperature variation information And a plate temperature control system in a continuous heat treatment furnace. The updating means includes
Based on the actual plate temperature on the furnace exit side, plate temperature variation information calculating means for calculating plate temperature variation information in the longitudinal direction of the steel plate,
Comparison means for comparing the plate temperature variation information in the longitudinal direction of the steel sheet calculated by the plate temperature variation information calculation means with the preset target plate temperature variation information;
Feedback control information calculation means for calculating feedback control information according to the comparison result by the comparison means,
The plate temperature control system in a continuous heat treatment furnace according to claim 1, wherein the feedback control information stored in the feedback control information storage means is updated using the feedback control information calculated by the calculation means. The feedback control means executes feedback control at a constant cycle,
The plate temperature control system for a continuous heat treatment furnace according to claim 1 or 2, wherein the update means executes update processing of feedback control information at a feedback control timing by the feedback control means. A plate temperature control method in a continuous heat treatment furnace for feedback control of the plate temperature of a strip-shaped steel plate heat-treated in a continuous heat treatment furnace,
Reads according to the previous process information and the target plate temperature on the furnace exit side from the feedback control information storage means for storing the pre-process information of the continuous heat treatment furnace, the target plate temperature on the furnace exit side, and the feedback control information in association with each other. A procedure for executing feedback control for the continuous heat treatment furnace based on the feedback control information;
Procedure for obtaining plate temperature variation information in the longitudinal direction of the steel plate based on the actual plate temperature on the furnace exit side, and updating the feedback control information stored in the feedback control information storage means according to the plate temperature variation information And a plate temperature control method in a continuous heat treatment furnace. A program for feedback control of the plate temperature of a strip-shaped steel plate heat-treated in a continuous heat treatment furnace,
Reads according to the previous process information and the target plate temperature on the furnace exit side from the feedback control information storage means for storing the pre-process information of the continuous heat treatment furnace, the target plate temperature on the furnace exit side, and the feedback control information in association with each other. Based on the feedback control information, processing for executing feedback control for the continuous heat treatment furnace,
Processing for obtaining plate temperature variation information in the longitudinal direction of the steel plate based on the actual plate temperature on the furnace exit side, and updating the feedback control information stored in the feedback control information storage means according to the plate temperature variation information A program that causes a computer to execute.

Images