JP2004306097A - Slag outflow detector. slag outflow detection method, computer readable storage medium, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to rapidly and exactly perform discrimination of slag outflow. <P>SOLUTION: When injecting molten metal from a vessel containing the molten metal and slag through a sealed circulation pipe into another vessel, a vibration level measurement signal is prepared by measuring the vibration level generated in the sealed circulation pipe with time and a delay vector is prepared on the basis of the vibration level measurement signal. Slag outflow is discriminated by detecting the change in the recurrence plot structure prepared on the basis of the reconstitution attractor drawn by the delay vector, and consequently, the exact capturing of the temporal change in the state of the sealed circulation pipe to be detected is made possible and the rapid and accurate decision of the outflow of the slag from a ladle to a tundish is made possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a slag outflow detection device, a slag outflow detection method, a computer-readable storage medium, and a computer program. In particular, the present invention relates to a method for transferring molten metal from a container containing molten metal and slag to another container through a sealed flow pipe. It is suitable for use in a slag outflow detection method for detecting that slag flows out of another container through a sealed flow tube when pouring slag.
[0002]
[Prior art]
After the molten steel refined in the converter is transferred to a ladle, it is poured into a tundish through an air seal pipe in continuous casting. Normally, slag is added to the ladle with molten steel.When pouring molten steel into the tundish from the ladle, a large amount of slag flows into the tundish at the end of pouring. As a result, the slag is caught in the mold of the continuous casting machine and remains as an internal defect in the continuously cast slab. Therefore, an operation is performed so that slag does not flow into the tundish as much as possible. FIG. 7 is a diagram showing a state in which such molten steel is poured into a tundish. In FIG. 7, reference numeral 21 is a ladle, 22 is a slag in the ladle 21, 23 is molten steel in the ladle 21, 24 is a ladle nozzle, 27 is a tundish, 28 is a dipping nozzle, 29 is a mold, and SN is Ladle opening and closing valve.
[0003]
The slag 22 is floating on the surface of the molten steel 23 in the ladle 21, but as the molten metal 23 falls to a certain level with the progress of pouring into the tundish 27, the ladle nozzle A vortex is generated in the upper part of 24, and the slag 22 flows out to the tundish 27 together with the molten steel 23.
[0004]
As a method of detecting the outflow of the slag 22 from the ladle 21 to the tundish 27, a method of measuring the vibration level generated in the ladle nozzle 24 over time and detecting the outflow of the slag based on the change in the vibration level There is. This slag outflow detection method is based on the following principle.
[0005]
The molten steel 23 in the ladle 21 passes through the ladle nozzle 24, falls freely by gravity, and collides with the molten metal surface 27 a in the tundish 27. Due to this fluid collision, the tip of the ladle nozzle 24 is vibrated, and the ladle nozzle 24 is vibrated.
[0006]
When the slag 22 flows out in place of the molten steel 23, the specific gravity of the slag 22 is 1/3 of the specific gravity of the molten steel 23. The vibration force is reduced, and the vibration level generated at the ladle nozzle 24 is reduced as compared with the case of the molten steel 23.
[0007]
As a specific conventional method for detecting the outflow of slag from a ladle to a tundish based on such a principle, there is a technique disclosed in Patent Document 1. A slag outflow detection method based on this technique is used in a continuous casting apparatus for pouring molten metal from a ladle to a tundish 27 through a long nozzle (air seal pipe) when detecting the ladle pouring end point. That is, vibration accelerations of at least two different directions of the long nozzle are sensed, and slag outflow is detected from the sensed vibration.
[0008]
That is, the slag outflow detection method utilizes that the vibration intensity generated from the pouring equipment changes when the slag flows out, relative to the vibration intensity generated when the molten metal flows.
[0009]
However, the slag outflow detection method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-164124 has the following problems. That is, (a) the flow rate of molten steel per unit time poured from a ladle into a tundish varies depending on the casting speed, casting width, etc. of the slab, and the vibration intensity also changes. It is difficult to detect whether or not the vibration intensity has changed with reference to.
[0010]
(B) Since the generation of vibration is based on the excitation by the fluid force, the vibration intensity changes irregularly, and it is difficult to detect the vibration change when the slag flows out of this change. Difficult to quantify.
[0011]
In order to solve such a problem, Patent Literature 2 proposes a “slag outflow detection method” that enables a signal processing circuit to automatically detect a change in vibration intensity due to slag outflow. .
[0012]
According to the "slag outflow detection method", the vibration level generated at the ladle nozzle 24 is measured with time, and the moving average is calculated for each of two different times in which the length of time for averaging the measured vibration levels is different Performing the processing, the magnitude of the averaged vibration level of the shorter averaging time after the moving average processing is determined by the magnitude of the averaged vibration level of the longer averaging time after the moving average processing. When the divided value becomes smaller than a predetermined value, the operator determines that the slag has flowed out.
[0013]
[Patent Document 1]
JP-A-7-164124 [Patent Document 2]
JP 2000-117407 A
[Problems to be solved by the invention]
However, conventionally, the slag outflow is determined as described above, so that the operator can determine the slag outflow after a certain time has elapsed since the slag outflow actually occurred.
[0015]
Therefore, conventionally, a large amount of the slag 22 flows into the tundish 27, so that the quality of the cast slab is deteriorated, which hinders an improvement in product yield.
[0016]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to enable slag outflow determination to be performed quickly and accurately.
[0017]
[Means for Solving the Problems]
The method for detecting slag outflow of the present invention is characterized in that, when the molten metal is injected from a container containing the molten metal and the slag into another container via a sealed flow pipe, the slag is filled with the sealed flow pipe. A slag outflow detection method for detecting the outflow to the other container through, the vibration level generated in the sealed flow pipe is measured with time to create a vibration level measurement signal, and the created A delay vector is created based on the measured vibration level measurement signal, a recurrence plot is created based on a reconstructed attractor drawn by the created delay vector, and a slug is generated based on a change in the plot structure on the recurrence plot. It is characterized by determining outflow.
Another feature of the present invention is that, in the determination of the slag outflow, in a line segment parallel to a diagonal line of the recurrence plot, a portion where autocorrelation is reduced after a large unsteady state has appeared appears. Then, when a plot structure change in which a large unsteady state reappears thereafter is detected, it is determined that slag outflow has occurred.
Another feature of the present invention is that a neighboring point on the reconstructed attractor existing around a point at the reference time on the reconstructed attractor drawn by the created delay vector changes by a predetermined time from the reference time. After calculating the ratio of how many points exist around the point, the vibration state is converted into a numerical index, and after the recurrence plot structure change appears, when it is detected that the numerical index changes, a slag outflow occurs. It is characterized in that it has been determined that they have been performed.
Another feature of the present invention is that a vibration level generated in the sealed flow pipe is measured over time, and a delay vector is created based on the measured signal. It is characterized by being based on a time-series signal obtained from vibration measurement in two-dimensional or three-dimensional directions of a tube.
Another feature of the present invention is to use a signal in a period band of 0.04 to 1.5 seconds in measuring a vibration level generated in the sealed flow pipe over time. The sampling interval is 0.02 seconds to 0.75 seconds.
[0018]
The slag outflow detection device of the present invention, when injecting the molten metal from a container containing the molten metal and slag into another container via a sealed flow pipe, the slag is the sealed flow pipe A slag outflow detection device for detecting the outflow to the other container through the slag, wherein a vibration level generated in the sealed flow pipe is measured with time to generate a vibration level measurement signal. Means, a delay vector creating means for creating a delay vector based on the vibration level measurement signal measured by the vibration level measurement signal creating means, and a reconstruction attractor drawn by the delay vector created by the delay vector creating means. And a recurrence plot creating means for creating a recurrence plot, and a recurrence plot created by the recurrence plot creating means. It is characterized by having a slag outflow determining means for determining a slag outlet on the basis of changes in the plot structure on Nsu plot.
According to another feature of the present invention, the slag outflow determination means includes a line segment parallel to a diagonal line of the recurrence plot, in which a portion where autocorrelation decreases after a large unsteady state appears. Then, when a plot structure change in which a large unsteady state reappears thereafter is detected, it is determined that slag outflow has occurred.
Another feature of the present invention is that the slag outflow determination unit determines that the neighboring point on the reconstructed attractor present around the point at the reference time on the reconstructed attractor drawn by the delay vector is the reference point. When a ratio of how many exist around a point after a predetermined time transition from time is calculated and the vibration state is converted into a numerical index, and after the recurrence plot structure change appears, when it is detected that the numerical index changes. It is characterized in that it is determined that slag outflow has occurred.
Further, another feature of the present invention is that a vibration level generated in the sealed flow pipe is measured with time, and a delay vector is created based on the measured signal. It is characterized by being based on a time-series signal obtained from vibration measurement in two-dimensional or three-dimensional directions of a tube.
Another feature of the present invention is to use a signal in a period band of 0.04 seconds to 1.5 seconds in measuring a vibration level generated in the sealed flow pipe over time. It is characterized by:
[0019]
A storage medium according to the present invention is characterized by recording a program for causing a computer to function as each of the above-described units.
Another feature of the storage medium of the present invention is that a program for causing a computer to execute the method described above is recorded.
[0020]
Further, a computer program of the present invention causes a computer to execute the method described above.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of a slag outflow detection device, a slag outflow detection method, a computer-readable storage medium, and a computer program of the present invention will be described with reference to the accompanying drawings.
[0022]
FIG. 1 is a functional configuration diagram showing an embodiment of a slag outflow detection device according to the present invention. As shown in FIG. 1, the slag outflow detecting device according to the present embodiment includes an arithmetic unit 10 and a measuring unit 11.
[0023]
The arithmetic unit 10 is provided as a vibration level measurement signal generating means, and generates a vibration level measurement signal by measuring a vibration level generated in the above-mentioned sealed circulation pipe with time.
[0024]
The calculation unit 10 includes a delay vector creation unit 10a, a recurrence plot creation unit 10b, a slag outflow determination unit 10c, and the like.
The delay vector creation unit 10a is provided as delay vector creation means, and creates a delay vector based on the vibration level measurement signal created by the measurement unit 11.
[0025]
The recurrence plot creation unit 10b is provided as recurrence plot creation means, and creates a recurrence plot based on a reconstructed attractor drawn by the delay vector created by the delay vector creation unit 10a.
[0026]
The slag outflow determination unit 10c is provided as slag outflow determination means, and determines slag outflow based on a change in the plot structure on the recurrence plot created by the recurrence plot creation unit 10b.
[0027]
The ladle nozzle control device 12 controls the open / close state of the ladle nozzle 13 based on the determination result of the slag outflow determination unit 10c to prevent the slag in the ladle from flowing into the tundish. .
[0028]
In the present embodiment, the slag outflow judging unit 10c generates a portion where the autocorrelation decreases after a large unsteady state appears in a line segment parallel to the diagonal line of the recurrence plot. When a change in the plot structure in which the state reappears is detected, it is determined that slag outflow has occurred.
[0029]
In addition, the slag outflow determination unit 10c determines that a neighboring point on the reconstructed attractor that exists around the point at the reference time on the reconstructed attractor drawn by the delay vector is around the point after a predetermined time transition from the reference time. The vibration state is converted into a numerical index by calculating the ratio of the number of the vibration states. Then, when a change in the numerical index is detected after a structural change in the recurrence plot appears, it is determined that slag outflow has occurred.
[0030]
Next, the operation of the slag outflow detection device of the present embodiment configured as described above will be described with reference to the flowchart of FIG.
When the process is started, in the first step S21, the vibration level of the ladle nozzle (the ladle nozzle 24 in FIG. 7) is measured by the measuring unit 11.
[0031]
FIG. 3 shows a wavelet multi-resolution analysis result of the vibration value by the high frequency sensor. In FIG. 3, information on slag outflow appears in a periodic band around 0.04 to 1.28 seconds.
[0032]
Next, the process proceeds to step S22, where a reconstructed attractor is created. The reconstructed attractor obtains a delay vector v (t) having a dimension twice or more as large as a target phenomenon from a vibration level measurement signal, and creates the delay vector v (t).
v (t) = (Sx (t), Sx (t−τ), Sx (t−2τ)..., Sy (t), Sy (t−τ), Sy (t−2τ),. , Sz (t), Sz (t−τ), Sz (t−2τ),...)
Create by Here, x, y, and z indicate the coordinates of the vibration measurement axis, and τ indicates the delay time.
[0033]
Next, the process proceeds to step S23, where a recurrence plot is created using the vibration level generated in the sealed flow pipe as a variable. The recurrence plot is a two-dimensional display of the unsteady behavior of the reconstructed attractor created with delay coordinates having dimensions twice or more that of the prototype phenomenon.
[0034]
In the present embodiment, the recurrence plot searches for a nearby point within a predetermined distance from a current time point on the reconstruction attractor from a point on the reconstruction attractor. As a result, the time of the searched neighboring point is created by two-dimensionally displaying the horizontal axis as the current time and the vertical axis as the time of the neighboring point.
[0035]
Next, the process proceeds to step S24, in which a predetermined change in the recurrence plot is detected to detect slag outflow. This is because when the slag flows out of the vessel containing the molten metal and the slag (the ladle 21 in FIG. 7) into the sealed flow pipe, the specific gravity of the slag is about 1/3 of the molten steel, and the fluid flows through the pipe. In this embodiment, the attenuation of the vibration is detected as an increase in the density of line segments parallel to the diagonal line on the recurrence plot because the force applied to the wall decreases and the vibration attenuates.
[0036]
That is, once the outflow of the slag starts, the surface of the slag in the container containing the molten metal and the slag is deformed and bubbles are trapped therein, thereby causing irregular vibration. This irregular vibration is expressed as a state of high non-stationaryity on the recurrence plot, and the plot becomes blank.
[0037]
This will be described with reference to FIG. In FIG. 4, (1) is a characteristic diagram of a vibration value, (2) is a recurrence plot, and (3) is a characteristic diagram of a continuity evaluation index.
As shown in FIG. 4, in the present embodiment, the diagonal line of the recurrence plot is represented by the horizontal axis of the graph in order to make it easy to see the line parallel to the diagonal line in the recurrence plot.
[0038]
In FIG. 4, the vibration state of the ladle nozzle changes after −60 seconds, and a dense parallel line representing the vibration attenuation state appears on the recurrence plot. After that, a state where there is no parallel line, that is, a phenomenon in which unsteady vibration of a white spot suddenly appears can be clearly observed. In the present embodiment, when a pattern “white → closed parallel line → white” is detected, it is determined that slag outflow has occurred.
[0039]
Looking at the behavior of the continuity evaluation index shown in (3) of FIG. 4, it can be detected that the rapid decrease of the index, which is considered to be slag outflow, is more than 15 seconds earlier than the judgment of the operator. You can see that there is.
[0040]
FIG. 5 shows the result of comparison between the chaos determination time and the operator determination time. As is clear from FIG. 5, it can be seen that the chaos detection detects a sign of slag outflow about 13 seconds earlier than the operator determination.
[0041]
Next, in step S25, it is determined whether or not to end the processing. If not, the process returns to step S21 to repeat the above-described processing.
[0042]
In addition, a vibration level generated in the sealed circulation pipe (the ladle nozzle 24 in FIG. 7) is measured with time, and a delay vector is created based on the measured signal. A time-series signal obtained from a two-dimensional or three-dimensional vibration measurement may be used.
[0043]
As described with reference to FIG. 3, when measuring the vibration level generated in the sealed flow pipe with the lapse of time, a signal in a period band of 0.04 to 1.5 seconds is used. Can be satisfactorily detected.
[0044]
FIG. 6 is a block diagram illustrating a configuration example of a computer system that can configure the slag outflow detection device according to the present embodiment.
6, reference numeral 600 denotes a computer PC. The PC 600 includes a CPU 601 and executes device control software stored in the ROM 602 or the hard disk (HD) 611 or supplied from the flexible disk drive (FD) 612 to comprehensively control each device connected to the system bus 604. To control.
[0045]
Each functional unit of the present embodiment is configured by a program stored in the CPU 601, the ROM 602, or the hard disk (HD) 611 of the PC 600.
[0046]
A RAM 603 functions as a main memory, a work area, and the like for the CPU 601. A keyboard controller (KBC) 605 controls input of a signal input from the keyboard (KB) 609 into the system main body. A display controller (CRTC) 606 performs display control on a display device (CRT) 610. Reference numeral 607 denotes a disk controller (DKC), which is a hard disk that stores a boot program (starting program: a program for starting execution (operation) of hardware and software of a personal computer), a plurality of applications, editing files, user files, a network management program, and the like. HD) 611 and flexible disk (FD) 612.
[0047]
A network interface card (NIC) 608 exchanges data with a network printer, another network device, or another PC via the LAN 620 in two directions.
[0048]
(Another embodiment of the present invention)
The present invention may be applied to a system including a plurality of devices or an apparatus including one device.
[0049]
In addition, a transmission medium such as the Internet or the like is transmitted to a computer in an apparatus or a system connected to the various devices so as to operate various devices so as to realize the functions of the above-described embodiments. A program implemented by supplying software program codes for realizing the functions of the above-described embodiments via a computer (CPU or MPU) of the system or apparatus according to the program stored in the computer or the MPU. Are included in the scope of the present invention.
[0050]
In this case, the program code of the software itself realizes the function of the above-described embodiment, and the program code itself and a unit for supplying the program code to the computer, for example, storing the program code The storage medium described constitutes the present invention. As a storage medium for storing such a program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, and the like can be used.
[0051]
When the computer executes the supplied program code, not only the functions described in the above-described embodiments are realized, but also the OS (Operating System) or other operating system running on the computer. Needless to say, the program code is included in the embodiment of the present invention even when the functions described in the above embodiment are realized in cooperation with application software or the like.
[0052]
Further, after the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, a CPU provided in the function expansion board or the function expansion unit based on the instruction of the program code. The present invention also includes a case where the functions of the above-described embodiments are implemented by performing part or all of the actual processing.
[0053]
【The invention's effect】
As described above, according to the present invention, when injecting molten metal from a container containing molten metal and slag into another container via a sealed flow pipe, the slag is sealed. In order to detect the flow through the closed flow pipe to another container, a vibration level generated in the sealed flow pipe is measured with time to generate a vibration level measurement signal, and the vibration level is measured. A delay vector is created based on the measurement signal, and the slag outflow is determined based on a change in the recurrence plot structure based on the reconstruction attractor drawn by the delay vector. Can be accurately grasped over time, and slag outflow determination can be performed quickly and accurately.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention and showing a schematic configuration of a slag outflow detecting device.
FIG. 2 is a flowchart illustrating an outline of a processing procedure of the slag outflow detecting device.
FIG. 3 is a diagram showing an example of a wavelet multi-resolution analysis result of a vibration value by a high-frequency compatible sensor.
FIG. 4 is a diagram illustrating an example of chaos indexing of ladle vibration.
FIG. 5 is a diagram illustrating an example of a comparison result between an operator determination and a chaos determination.
FIG. 6 is a block diagram illustrating an example of a hardware configuration of the slag outflow detection device.
FIG. 7 is a diagram illustrating a state to which the present invention is applied, and is a diagram illustrating a state in which molten steel is being poured into a tundish.
[Explanation of symbols]
Reference Signs List 10 arithmetic unit 10a delay vector creating unit 10b recurrence plot creating unit 10c slag outflow judging unit 11 measuring unit 12 ladle nozzle control device 13 ladle nozzle

Claims (13)

When injecting the molten metal from a container containing molten metal and slag into another container through a sealed flow pipe, the slag flows out to the other vessel through the sealed flow pipe. A slag outflow detection method for detecting
The vibration level generated in the sealed flow pipe is measured over time to create a vibration level measurement signal, and a delay vector is created based on the created measurement vibration level measurement signal, and the created delay vector is created. A recurrence plot is created based on a reconstructed attractor drawn by the method, and a slag outflow detection method is characterized by determining a slag outflow based on a change in the plot structure on the recurrence plot. The determination of the slag outflow is based on a plot structure in which, in a line segment parallel to the diagonal line of the recurrence plot, a portion where autocorrelation decreases after a large unsteady state appears, and then a large unsteady state appears again. The slag outflow detecting method according to claim 1, wherein it is determined that slag outflow has occurred when a change is detected. The ratio of how many neighboring points on the reconstructed attractor present around the point at the reference time on the reconstructed attractor drawn by the created delay vector exist around the point after a predetermined time transition from the reference time. And calculating the vibration state as a numerical index, and determining that a slag outflow has occurred when detecting that the numerical index changes after the occurrence of the recurrence plot structure change. 3. The slag outflow detection method according to 2. The vibration level generated in the sealed flow pipe is measured over time, and a delay vector is created based on the measured signal. The delay vector is obtained from two-dimensional or three-dimensional vibration measurement of the sealed flow pipe. The slag outflow detection method according to claim 1, wherein the method is based on a time-series signal obtained. In measuring the vibration level generated in the sealed flow pipe over time, a signal in a period band of 0.04 to 1.5 seconds is used, and a sampling interval is 0.02 to 0.75 seconds. The slag outflow detecting method according to claim 1, wherein the signal of (1) is used. When injecting the molten metal from a container containing molten metal and slag into another container through a sealed flow pipe, the slag flows out to the other vessel through the sealed flow pipe. A slag outflow detection device for detecting
Vibration level measurement signal creating means for creating a vibration level measurement signal by measuring the vibration level generated in the sealed flow pipe over time,
Delay vector creating means for creating a delay vector based on the vibration level measurement signal measured by the vibration level measurement signal creating means,
Recurrence plot creating means for creating a recurrence plot based on the reconstructed attractor drawn by the delay vector created by the delay vector creating means,
A slag outflow detecting device, comprising: a slag outflow determining unit that determines a slag outflow based on a change in a plot structure on a recurrence plot created by the recurrence plot creating unit. The slag outflow judging means has a plot structure in which, in a line segment parallel to a diagonal line of the recurrence plot, a portion where autocorrelation decreases after a large unsteady state appears, and then a large unsteady state reappears thereafter. The slag outflow detecting device according to claim 6, wherein it is determined that slag outflow has occurred when a change is detected. The slug outflow determination means may determine how many neighboring points on the reconstructed attractor present around the point at the reference time on the reconstructed attractor drawn by the delay vector around the point after a predetermined time transition from the reference time. The vibration state is converted into a numerical index by calculating the ratio of the slag, and after the occurrence of the recurrence plot structure change, when it is detected that the numerical index changes, it is determined that slag outflow has occurred. The slag outflow detection device according to claim 6. The vibration level generated in the sealed flow pipe is measured over time, and a delay vector is created on the basis of the measured signal. The delay vector is obtained from two- or three-dimensional vibration measurement of the sealed flow pipe. 7. The slag outflow detecting device according to claim 6, wherein the slag outflow detecting device is based on a time series signal obtained. 7. The slag outflow according to claim 6, wherein a signal in a period band of 0.04 seconds to 1.5 seconds is used for measuring a vibration level generated in the sealed flow pipe over time. Detection device. A computer-readable storage medium storing a program for causing a computer to execute the slag outflow detection method according to any one of claims 1 to 5. A computer-readable storage medium storing a program for causing a computer to function as each unit according to any one of claims 6 to 10. A computer program for causing a computer to execute the slag outflow detection method according to any one of claims 1 to 5.

Images