JP4746466B2 - Slag outflow detection method, molten metal injection control method, slag outflow detection device, molten metal injection control device, program, and computer-readable recording medium - Google Patents

Description

  The present invention relates to a slag outflow detection method, a molten metal injection control method, a slag outflow detection device, a molten metal injection control device, a program, and a computer-readable recording medium, and in particular, from a container containing molten metal and slag. TECHNICAL FIELD The present invention relates to a technique suitable for use in detecting that the slag flows out to another container through the sealed circulation pipe when molten metal is injected into the other container via the distributed circulation pipe. .

  In continuous casting, molten steel smelted in a converter is transferred to a ladle and then poured into a tundish through a long nozzle. FIG. 13 is a view showing a state in which such molten steel is poured into the tundish. In FIG. 13, reference numeral 81 is a ladle, 82 is a slag in the ladle 81, 83 is molten steel in the ladle 81, 84 is a long nozzle, 85 is a tundish, 86 is an immersion nozzle, 87 is a mold, and SN is a take-up. Pan open / close valve.

  Usually, since the ladle 81 contains the slag 82 together with the molten steel 83, when the molten steel 83 is poured from the ladle 81 into the tundish 85, a large amount of slag 82 flows into the tundish 85 at the end of pouring. Then, slag is mixed into the molten steel in the tundish 85, and as a result, the slag is caught in the mold 87 of the continuous casting machine and remains as an internal defect in the continuously cast slab.

  Therefore, the operation is performed so that the slag 82 does not flow into the tundish 85 as much as possible. For one thing, since the outflow of the slag 82 from the ladle 81 occurs at the end of the pouring, the weight of the ladle 81 is measured and poured at a stage when a predetermined remaining hot water amount with a low probability of slag flowing out is reached. It is a way to stop hot water. The other is a method of stopping pouring by detecting the start of slag outflow from the ladle 81.

  Various methods have been tried in the past to detect the start of slag flow from the ladle, and two typical methods will be described. The first method is a method based on human senses, and the second method is a method based on vibration measurement, which will be described below.

1) Method based on human senses There are two methods based on senses, one is a visual method, and the other is a tactile method.
(1) Visual method When the hot water surface 85a in the tundish 85 is carefully observed at the end of pouring, when the slag flows into the tundish 85, the slag rises on the surface. Slag outflow can be determined.
(2) Tactile method By touching a part of the support device of the long nozzle 84 and changing the strength of the vibration, the outflow of the slag can be determined.

2) Method by vibration measurement The molten steel 83 in the ladle 81 passes through the long nozzle 84, falls freely by gravity, and collides with the hot water surface 85a in the tundish 85. Due to this fluid collision, the tip of the long nozzle 84 is vibrated, and the long nozzle 84 vibrates.
At that time, when the slag 82 flows out in place of the molten steel 83, the specific gravity of the slag 82 is about 1/3 of the specific gravity of the molten steel 83. Therefore, the vibration level generated in the long nozzle 84 is reduced as compared with the case of the molten steel 83.

  Specific conventional methods for detecting the slag flowing out of the ladle 81 based on such a principle include, for example, the technique disclosed in Patent Document 1 and the technique disclosed in Patent Document 2.

  According to the method of Patent Document 1, the vibration level generated by the long nozzle 84 is measured over time, and the moving average process is performed every two hours with different lengths of time for averaging the magnitudes of the measured vibration levels. A value obtained by dividing the magnitude of the averaged vibration level of the shorter average time after the moving average process by the magnitude of the averaged vibration level of the longer average time after the moving average process However, when it becomes smaller than a predetermined value, it is determined that the slag has flowed out.

  According to the method of Patent Document 2, “activity” is defined as a numerical index indicating the vibration intensity at each time, and it is determined that slag has flowed out with the same numerical attenuation.

JP 2000-117407 A JP 2004-268122 A

  In the method of judging the stop of pouring by the weight of the ladle, the timing of slag outflow is not constant between charges, so to prevent slag outflow as much as possible, stop pouring at the stage before slag outflow. Therefore, the yield of molten steel will be reduced. In addition, if the injection stop timing is delayed with emphasis on improving the molten steel yield, the probability of slag flowing out increases, which causes a reduction in slab quality.

  When trying to detect the start of slag outflow, whether it is a visual method or a tactile method, the method based on human sense requires the skill of the operator and is difficult to judge quickly even if it is skilled. It is.

  Further, as a method based on vibration measurement, Patent Document 1 discloses a method for determining the start of slag outflow by processing vibration levels, but does not specify the vibration level to be used, for example, pouring hot water. There is a problem that the outflow of slag cannot be detected depending on conditions, such as when the flow rate of molten steel is very high, such as 10 tons / minute. On the other hand, since Patent Document 2 does not show a method for objectively determining the attenuation of the activity, there is a problem that the slag outflow start determination cannot be automated.

  Further, the flow rate of the molten steel to be poured in order to adjust the molten metal surface height in the tundish may be changed during the charging for operational reasons. In this case, the vibration level in Patent Document 1 Since the activity defined in Patent Document 2 is affected not only by the outflow of slag but also by the flow rate change of the molten steel, there is a possibility that the determination of outflow of slag may be erroneous.

  Furthermore, since it is not possible to completely prevent the slag from flowing out, when manufacturing a high cleanliness steel, the part excluding a certain length from the position when the slab is replaced is used as the product. Whether or not is passed is not known until after rolling. Therefore, there is a problem that there is always a possibility that the yield of the rolled product is reduced.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to enable a slag outflow determination to be performed quickly and accurately.

In the slag outflow detection method of the present invention, when the molten metal is injected from a container containing molten metal and slag into another container via a sealed distribution pipe, the slag is sealed in the distribution pipe. A slag outflow detection method for detecting outflow to the other container through,
A vibration level measuring step for measuring a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe over time;
A delay vector creating step of creating a delay vector based on the vibration measurement signal measured in the vibration level measuring step;
On the reconstructed attractor drawn by the delay vector created in the delay vector creating step, an activity calculating step for obtaining an activity obtained by numerically indexing the vibration state at each time;
The activity obtained in the activity calculating step is the standard activity indicating the average value of the activity obtained in the time zone in which the slag does not flow out, the average of the molten metal flow rate obtained in the time zone in which the slag does not flow out. A corrected activity calculation step of calculating a corrected activity by correcting using a reference molten metal flow rate indicating a value and an activity estimation formula when the molten metal flow rate changes,
A slag outflow detection step of detecting slag outflow based on the corrected activity calculated in the correction activity calculation step ,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
And the constant C in the above equation is:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
It is characterized by being a constant in .
Further, another feature of the slag outflow detection method of the present invention is that the activity estimation formula when the molten metal flow rate used in the correction activity calculation step is the activity before the change in the same charge, the melting It is estimated from the metal flow rate and the molten metal flow rate after the change.
Another feature of the slag outflow detection method of the present invention is that, in the slag outflow detection step, if the average change rate of the correction activity falls below a preset threshold, it is determined that the correction activity starts to decay. In addition, it is characterized in that it is determined that the slag outflow starts with the start of decay of the correction activity.

  According to the molten metal injection control method of the present invention, after a lapse of a certain time from the slag outflow start time determined by the slag outflow detection method according to any one of the above, the sealed from the container containing the molten metal and slag The injection of the molten metal into another container through the flow pipe is stopped.

The slag outflow detection device according to the present invention is configured to inject the molten metal from a container containing molten metal and slag into another container through a sealed distribution pipe. A slag outflow detection device for detecting outflow to the other container through,
A vibration level measuring means for measuring a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe with time, and a delay vector based on a vibration measurement signal measured by the vibration level measuring means. A delay vector creating means for creating, an activity calculating means for obtaining an activity level by numerically indexing a vibration state at each time on a reconstructed attractor drawn by the delay vector created by the delay vector creating means, and the activity calculating Standard activity indicating the average value of the activity obtained during the time zone when the slag does not flow out, and the standard indicating the average value of the molten metal flow obtained during the time zone when the slag does not flow out A corrected activity calculating means for calculating a corrected activity by correcting using a molten metal flow rate and an activity estimation formula when the molten metal flow is changed, and the corrected activity calculating means. Based on the calculated correction activity and a slag outlet detecting means for detecting the outflow of slag,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
The constant C in the above formula is expressed by the following relational expression:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
It is characterized by being a constant in.
Another feature of the slag outflow detection device according to the present invention is that the activity estimation formula when the molten metal flow rate used by the correction activity calculation means is the activity before the change in the same charge, the melting It is estimated from the metal flow rate and the molten metal flow rate after the change.
Another feature of the slag outflow detection device of the present invention is that the slag outflow detection means determines that the correction activity starts to be attenuated when the average change rate of the correction activity falls below a preset threshold. Further, it is characterized in that it is determined that the slag outflow starts with the start of the decay of the correction activity.

  The molten metal injection control device of the present invention is sealed from a container containing the molten metal and slag after a lapse of a certain time from the slag outflow start time determined by the slag outflow detection device according to any one of the above. The injection of the molten metal into another container through the flow pipe is stopped.

When the molten metal is injected from a container containing molten metal and slag into another container through a sealed flow pipe, the other slag passes through the sealed flow pipe. A program for causing a computer to execute a slag outflow detection method for detecting outflow into a container of a container, and measures a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe over time. On the vibration level measurement step, a delay vector creation step for creating a delay vector based on the vibration measurement signal measured in the vibration level measurement step, and a reconstruction attractor drawn by the delay vector created in the delay vector creation step, The activity level calculation step for obtaining the activity level obtained by numerically indexing the vibration state at the time and the activity level calculated in the activity level calculation step are The standard activity indicating the average value of the activity obtained during the time zone when the slag does not flow out, the reference molten metal flow rate indicating the average value of the molten metal flow rate obtained during the time zone when the slag does not flow out, and the change in molten metal flow Correction activity calculation step of calculating a corrected activity by correcting using an activity activity estimation formula, and slag outflow detection for detecting slag outflow based on the corrected activity calculated in the corrected activity calculation step A process ,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
The constant C in the above formula is expressed by the following relational expression:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
The slag outflow detection method is characterized in that the computer executes the slag outflow detection method.

  The recording medium of the present invention is characterized by recording the program described above.

According to the present invention, slag outflow determination can be performed quickly and accurately. Thereby, in the continuous casting process, the quality of the part formed at the time of exchanging the pan of the slab can be improved, and the length of the portion to be removed when manufacturing the high cleanliness steel can be reduced. Moreover, the amount of remaining hot water in the ladle can be reduced as much as possible, and the yield can be improved.
In addition, according to another aspect of the present invention, it is possible to automatically determine the slag outflow and close the long nozzle, reduce the work on site, and maintain high cleanliness without relying on operator skill. Steel can be manufactured.
Moreover, according to the other characteristics of this invention, it can use universally irrespective of operation conditions, such as a tundish depth and the position of a long nozzle.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Although the present embodiment is mainly applied to continuous casting, it can also be applied to non-ferrous metal casting such as DC casting of aluminum when there is a need to prevent the outflow of slag as much as possible.

  FIG. 1 is a functional configuration diagram illustrating an embodiment of a slag outflow detection device according to the present embodiment. As shown in FIG. 1, the slag outflow detection device of the present embodiment includes a calculation unit 10 and a vibration level measurement unit 11.

  The vibration level measuring unit 11 is provided as a vibration level measuring means, and measures the vibration level generated in the sealed flow pipe (long nozzle) 20 (see FIG. 2) over time. Create a vibration level measurement signal.

  The arithmetic unit 10 includes a delay vector creation unit 10a, a slag outflow determination unit 10b, and the like. The delay vector creation unit 10 a is provided as a delay vector creation unit, and creates a delay vector based on the vibration level measurement signal created by the vibration level measurement unit 11.

  The slag outflow determination unit 10b is provided as a slag outflow determination unit, and determines slag outflow based on the time behavior of the reconstructed attractor drawn by the delay vector created by the delay vector creation unit 10a.

  The long nozzle control device 12 controls the open / closed state of the long nozzle 13 based on the determination result of the slag outflow determination unit 10b to prevent the slag in the ladle described above from flowing into the tundish.

  In the present embodiment, the slag outflow determination unit 10b determines how neighboring points on the reconstruction attractor existing around the point at the reference time on the reconstruction attractor drawn by the delay vector creation unit 10a are on the phase space. It has a means for numerically indexing the vibration state using the principal component value obtained by calculating the vibration intensity at each time by the principal component analysis method. Then, when it is detected that the numerical index is changed, it is determined that slag outflow has occurred.

  FIG. 2 is a diagram showing an outline of a lifting device for the long nozzle 20. The operator senses the vibration change of the long nozzle 20 as the vibration change of the operating handle 21 of the lifting device located about 1.5 m away from the long nozzle 20.

  Therefore, in the present embodiment, an acceleration sensor 22 is attached to the rightmost end of the operation handle 21, the vibration change of the long nozzle 20 is measured by the acceleration sensor 22, and the long nozzle 20 is slid based on the measurement result. The nozzle opening is closed.

Next, a processing procedure 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 S31, the vibration level of the long nozzle 20 is measured over time in the one-dimensional, two-dimensional or three-dimensional directions by the vibration level measuring unit 11 (acceleration sensor 22 in FIG. 2). .

Next, proceeding to step S32, a delay vector is created based on the vibration measurement signal measured at step S31.
Next, the process proceeds to step S33, and the degree of activity obtained by numerically indexing the vibration state at each time is calculated on the reconstructed attractor drawn by the delay vector created in step S32.

  Next, it progresses to step S34 and the process which correct | amends the activity calculated | required in step S33 is performed. This process consists of a reference activity indicating the average value of the activity obtained during the time zone when the slag does not flow out, a reference molten metal flow rate indicating the average value of the molten metal flow obtained during the time zone when the slag does not flow out, and This is done using the activity estimation formula when the molten metal flow rate changes.

  Next, it progresses to step S35 and it is determined whether the slag outflow has started. This determination is made based on the corrected activity calculated in step S34. If the result of determination in step S35 is that slag has not flowed out, the process returns to step S31 and the above-described processing is repeated. If the result of determination in step S35 is that slag has flowed out, the process proceeds to step S36, where the opening of the long nozzle 20 is closed.

  In the processing in step S32 and step S33, the characteristic of the nozzle vibration change is captured on the high-dimensional phase space reconstructed based on the vibration acceleration measurement value of each axis by using the method of chaotic time series analysis. To do.

  Then, in order to evaluate the magnitude of the nozzle vibration on the reconstructed attractor, the principal component analysis method is used to determine how the neighboring points of each time point of the reconstructed attractor have a spatial spread on the phase space. Quantify. That is, the neighborhood point on the reconstructed attractor is representative of the nature of the vibration at each time, and is based on the idea that the magnitude of the vibration corresponds to the spatial extent of the neighborhood point. The specific analysis procedure is as follows.

(1) The dimension of the long nozzle vibration acceleration of each axis of x, y, z is calculated.
The dimension of the system from the time series data is determined by the correlation dimension shown below. That is, a point included in a hypersphere having a radius ε drawn around a certain point v _k (i) on a reconstructed attractor created based on the following equation (1) assuming a certain dimension m Count the number of neighbors of v _k (i). A similar operation is performed over the entire reconstruction attractor, and the sum N (ε) of these neighboring points is obtained by the following equation (2).

Here, S _k indicates a measured value of vibration acceleration at each time, and τ is a sampling period. I (t) is a snake side function and is defined by the following equation (3).
I (t) = 1 (t ≧ 0), 0 (t <0) (3)
At this time, the relationship shown in the equation (4) is established between the dimension m of the system and N (ε) and ε.
log (N (ε)) ∝m · log (ε) (4)
The relationship between log (N (ε)) and log (ε) is plotted, and the correlation dimension m is determined from the slope of the straight line.

FIG. 4 shows the relationship between the log (N (ε)) and log (ε) for each of the x, y, and z axes. From the linear gradient in each characteristic diagram, the correlation dimension of vibration acceleration of each axis was determined as follows.
x-axis correlation dimension m _x = 7.2 (5)
y-axis correlation dimension m _y = 6.9 ··· (6)
z-axis correlation dimension m _y = 8.2 ··· (7)
The average value of these three-axis correlation dimensions was taken, and the representative correlation dimension m of the long nozzle vibration acceleration was determined as follows.
Representative correlation dimension m = 7.43 (8)

(2) Create a delay vector for forming a reconstructed attractor for long nozzle vibration acceleration.
The embedding dimension was set to 15 by adopting a value more than twice the representative correlation dimension 7.43 of the vibration acceleration determined by the equation (8).
Then, using the vibration acceleration measurement values of the x, y and z axes, a 15-dimensional delay vector is constructed as shown in the following equation (9).

(3) A reconstructed attractor is created based on the delay vector v (t), and the activity is calculated.
v (t _n) of the closest vector v ^k _NN (t _n), calculates the component W _ij of (1 ≦ k ≦ N) to use in the following (10) and (11) from the covariance matrix W . N represents the number of nearest neighbor vectors, and 16 which is an embedding dimension + 1 is adopted.

Next, the eigenvalue λ _i of the covariance matrix W is calculated, and the activity is calculated from the definition formula (12).

Next, the process in step S34 will be described in detail.
Since the flow rate of the molten steel to be poured is not usually measured, it is calculated by the following method from the measured value of the tundish weight and the production rate of the slab. First, data of a certain time width is extracted from the time series data of the tundish weight, the gradient of the linear regression equation is obtained, and this is used as the average rate of change of the tundish weight. At this time, it is desirable to extract data within a range of about 10 seconds before and after each time. Next, the molten steel flow rate is calculated by equation (13).

Molten steel flow rate = billet production rate + average change rate of tundish weight (13)
Calculate the average activity and molten steel flow rate for at least 1 minute, preferably 3 minutes or more from the time when pouring progressed 50% to the time when 70% progressed with one charge, and each of the standard activities The reference molten steel flow rate.

  Here, the reason why the standard activity level and the standard molten steel flow rate are calculated before 70% progress is because the possibility of the slag outflow comes after that, and it is necessary to obtain it before that. . Further, the reason for obtaining after 50% progress is to wait until the casting is stable and the conditions other than the slag outflow are as constant as possible. Furthermore, the average time for ensuring the accuracy of the correction activity was set to “minimum of 1 minute, preferably 3 minutes or more”.

Activity time series data obtained by the above method, molten steel flow time series data, reference activity, reference molten steel flow, and activity estimation formula A (A ₀ , The corrected activity is calculated by the equation (14) using Q ₀ , Q).
Correction activity = F (activity, A (reference activity, reference molten steel flow rate, molten steel flow rate)) (14)

Here, F is a function that can determine the magnitude relationship of two positive values. For example,
F (a, b) = a / b (15)
Or
F (a, b) = a−b (16)
In the former case, the magnitude relationship between F (a, b) and 1 is the same as the magnitude relationship between a and b. In the latter case, the magnitude relationship between F (a, b) and 0 is a. Is equivalent to the magnitude relationship between and b.

The activity estimation formula A (A ₀ , Q ₀ , Q) when the molten steel flow rate changes is for estimating the activity when the molten steel flow rate changes when the slag does not flow out within the same charge. Needs to be created in advance. Two examples are given as the form of the formula.

Here, Q ₀ and A ₀ are the flow rate and activity before the change, Q and A are the flow rate and activity after the change, respectively, and C is a positive constant. What is important here is that the estimation formula has the following properties.
(1) When Q ₁ is equal to Q ₀ , A ₁ is equal to A ₀ ,
(2) When Q ₁ is greater than Q ₀ , A ₁ is greater than A ₀ ,
(3) When Q ₁ is smaller than Q ₀ , A ₁ is smaller than A ₀ .
In other words, if the molten steel flow rate does not change, the activity does not change. If the molten steel flow rate increases, the activity increases, and if the molten steel flow rate decreases, the activity decreases.

Next, the process in step S35 will be described in detail.
In the present embodiment, the slag outflow is determined with the attenuation of the correction activity, but the start of the correction activity attenuation is determined by the following method. Preferably, data of about 40 to 80 seconds of the corrected activity is extracted, and the slope of the linear regression equation is obtained from the extracted data, and this is used as the average rate of change of the corrected activity. Here, data extraction is performed within the same time range from the present time to the past and future.

  Therefore, for example, when the average rate of change is obtained from data for 60 seconds, the average rate of change at the current time is calculated when the corrected activity level after 30 seconds is obtained. Moreover, the reason why the lower limit of the data width for obtaining the average rate of change is set to 40 seconds is that the accuracy of the slag outflow start determination is lost if this is not satisfied. Moreover, the reason why the upper limit is set to 80 seconds is that if this time is exceeded, the quickness of the slag outflow start determination is lost.

  The time when the average change rate of the corrected activity becomes smaller than a predetermined value for the first time is determined as the start of attenuation. Since the threshold value at this time may be affected by the equipment conditions, it is necessary to investigate and set the same equipment in advance by the following method.

  The minimum value in each charge of the average rate of change of the correction activity is calculated for castings with a slag outflow of at least 5 charges, preferably for castings of 10 charges or more, and castings of 30 charges or less.

  “5 charges or more, preferably 10 charges or more” is for ensuring the reliability of the threshold, and “maximum 30 charges or less” is the charge data that can confirm the outflow of slag in actual operation. This is because it is difficult to collect a large number. An average M (negative value) and a standard deviation σ (positive value) of the minimum values are obtained, and “M + σ” is set as a threshold value.

In order to maintain the accuracy of the slag outflow start determination, the sampling period of the time series data is preferably 100 msec or less, more preferably 50 msec or less.
Assuming that the time from when the correction activity decay starts to when pouring is stopped is the activity decay time, if the activity decay time becomes longer, products that are shipped as high cleanliness steel will be rejected. Become. The upper limit of the time during which no rejected product occurs is obtained, and the pouring is stopped after this time has elapsed since the start of slag outflow.

(Second Embodiment)
FIG. 12 shows an example of a computer system capable of configuring a molten metal injection control device.
In FIG. 12, 1200 is a computer PC. The PC 1200 includes a CPU 1201, executes device control software stored in the ROM 1202 or the hard disk (HD) 1211, or supplied from the flexible disk drive (FD) 1212, and collects all devices connected to the system bus 1204. To control.

  Each functional unit of the present embodiment is configured by a program stored in the CPU 1201, the ROM 1202, or the hard disk (HD) 1211 of the PC 1200.

  A RAM 1203 functions as a main memory, work area, and the like for the CPU 1201. Reference numeral 1205 denotes a keyboard controller (KBC), which controls to input a signal input from the keyboard (KB) 1209 into the system main body. Reference numeral 1206 denotes a display controller (CRTC) which performs display control on the display device (CRT) 1210. A disk controller (DKC) 1207 is a hard disk (boot program (start program: a program that starts execution (operation) of personal computer hardware and software)), a plurality of applications, editing files, user files, a network management program, and the like. HD) 1211 and flexible disk (FD) 1212 are controlled.

  Reference numeral 1208 denotes a network interface card (NIC) that performs bidirectional data exchange with a network printer, other network devices, or other PCs via the LAN 1220.

(Other embodiments according to the present invention)
The steps of the slag outflow detection device, the molten metal injection control device, the slag outflow detection method, and the molten metal injection control method in the embodiment of the present invention described above are stored in a RAM or ROM of a computer. It can be realized by operating the programmed program. This program and a computer-readable recording medium recording the program are included in the present invention.

  In addition, the present invention can be implemented as, for example, a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system including a plurality of devices. The present invention may be applied to an apparatus composed of a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in FIG. 3) that realizes the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus. In addition, this includes a case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the recording medium for supplying the program include a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, and CD-RW. In addition, there are magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R), and the like.

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let It is also possible to execute the encrypted program by using the downloaded key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. In addition, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can also be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

  In this example, the result of continuous casting of steel using equipment (two strands) for simultaneously producing two slabs will be described. In the casting performed in this example, the slab sizes of both strands are all equal.

  When the flow rate of molten steel changed during charging, the effect on activity was investigated. Table 1 shows the charge conditions implemented for this purpose. It is confirmed that slag did not flow out in these charges. This is to avoid the influence of other factors from being mixed when examining the relationship between the change in activity and the change in the flow rate of molten steel.

  FIG. 5A is a characteristic diagram showing the relationship between the amount of change in log [activity] and the amount of change in log [molten steel flow rate] within one charge obtained from these castings. From this relationship, the estimation formula (17 ′) in the form of the following formula (17)

Is obtained. On the other hand, FIG.5 (b) is a characteristic view which shows the relationship between the fluctuation rate of activity, and the fluctuation rate of a molten steel flow rate. From this relationship, the estimation formula (18 ′) in the form of formula (18)

Is obtained.
With respect to the charge in which slag outflow was confirmed, the start of outflow was determined by the method of the present invention. 6 is an example of time series data of activity, and FIG. 7 is an example of time-series data of molten steel flow rate. Time 0 second in the characteristic diagram is the timing of the end of charge. The casting time for this charge is 30 minutes, and data for 3 minutes from -780 seconds, which is the time when the progress is 17 minutes / 30 minutes, to -600 seconds, which is the time when the progress is 20 minutes / 30 minutes (this is described in the embodiment) The standard activity and the standard molten steel flow rate were calculated using the above-mentioned conditions (from 50% to 70%), and the above formulas (17 ′) and (15) were applied to formula (14) (14 ′) The corrected activity is calculated by

The thin line in FIG. 8 shows the relationship between the obtained correction activity and casting time.

  As shown in FIG. 8, the activity (before correction) corresponding to the slight decrease in the molten steel flow rate in the time zone in which no slag flow occurred from −760 seconds to −600 seconds. Is decreasing. On the other hand, the correction activity tends to be flat, and it can be seen that the influence of the molten steel flow rate is removed. Further, the correction activity after −240 seconds is at a lower level than before. Further, the thick line in FIG. 8 shows the relationship between the correction activity and the casting time by obtaining the average rate of change for 60 seconds. -Take the minimum value around 240 seconds.

  Table 2 shows the charge conditions implemented to set the threshold of the average activity change rate for determining the start of slag outflow. The outflow of slag has been confirmed in all these charges, and the results of investigating the minimum value of the correction activity average change rate of each charge are also shown in Table 2.

  Table 3 shows a sample taken from this data and examined for the statistics regarding the minimum value of the average rate of change. As the number of specimens increases, the mean and standard deviation converge to almost constant values around five specimens, and the average and standard deviation can be obtained from casting with a minimum of 5 charges or more, preferably 10 charges or more. It shows validity. The average + standard deviation converges to −0.01, and when this value is used as a threshold value, the time when the average change rate of the corrected activity becomes smaller than the threshold value for the first time corresponds to the start of attenuation of the corrected activity. I understand that.

The method of Patent Document 1 was applied to the above-described charge in which the slag outflow start determination was performed by the method of the present embodiment. Since the vibration level used for the determination is not specified in this method, the square root of the square sum of the vibration acceleration S _k (k = x, y, z) defined by the equation (19) is used as the vibration level. To.

FIG. 9 is a characteristic diagram showing an example of time-series data of vibration levels. Using the vibration level ratio (A / B) obtained by dividing the short time t ₁ moving average A by the long time t ₂ moving average B, the slag outflow start determination is attempted. Since there is no particular restriction on how to specify t ₁ and t ₂ , FIG. 10 shows the vibration level ratio obtained with t ₁ as 1 second and t ₂ as 10 seconds. With this method, there is no decrease in the vibration level ratio corresponding to the start of slag outflow. That is, although the slag outflow has occurred, the outflow start determination cannot be performed.

  FIG. 11 is created by distinguishing the histogram of the charge activity decay time for manufacturing the high cleanliness steel by the pass / fail judgment of the quality of the shipping part. A rejected product has occurred for a charge with an activity decay time of 4 minutes or more. On the contrary, if the activity decay time is suppressed to less than 4 minutes, no rejected product has occurred. That is, it is possible to determine whether or not the quality of the high cleanliness steel shipping department is acceptable at the stage after casting.

It is a block diagram which shows embodiment of this invention and shows schematic structure of a slag outflow detection apparatus. It is a figure which shows the outline of the raising / lowering apparatus of a long nozzle. It is a flowchart for demonstrating the outline of the process sequence of a slag outflow detection apparatus. It is a figure explaining the relationship between the correlation integral of a long nozzle vibration acceleration, and a hypersphere diameter. (A) is a characteristic diagram showing the relationship between the fluctuation amount of log [activity] and the fluctuation amount of log [molten steel flow rate] within one charge, and (b) is the fluctuation rate of activity and the fluctuation rate of molten steel flow rate. It is a characteristic view which shows the relationship. It is a characteristic view which shows the example of the time series data of an activity degree. It is a characteristic view which shows the example of the time series data of molten steel flow volume. It is a characteristic view which shows the relationship between correction | amendment activity and casting time. It is a characteristic view which shows the example of the time series data of a vibration level. It is a characteristic view which shows the relationship between a vibration level ratio and casting time. It is a figure which distinguishes and distributes the activity decay time distribution of the charge which manufactured high cleanliness steel by the pass / fail determination of the quality of a shipment site | part. It is a block diagram which shows an example of the computer system which can comprise the injection control apparatus of a molten metal. It is a figure explaining the state to which this invention is applied, Comprising: It is a figure which shows the state by which molten steel is poured into the tundish.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Calculation part 10a Delay vector preparation part 10b Slag outflow determination part 11 Vibration level measurement part 12 Long nozzle control device 13 Long nozzle 20 Long nozzle 21 Operation handle 22 Acceleration sensor 81 Ladle 82 Slag 83 Molten steel 84 Long nozzle 85 Tundish 85a Tan Hot water surface 86 in the dish 87 Immersion nozzle 87 Mold SN Ladle open / close valve 1200 Computer PC
1201 CPU
1202 ROM
1203 RAM
1204 System bus 1205 KBC
1206 CRTC
1207 DKC
1208 NIC
1209 KB
1210 CRT
1211 HD
1212 FD
1220 LAN

Claims (10)

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 container through the sealed flow pipe. A slag outflow detection method for detecting
A vibration level measuring step for measuring a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe over time;
A delay vector creating step of creating a delay vector based on the vibration measurement signal measured in the vibration level measuring step;
On the reconstructed attractor drawn by the delay vector created in the delay vector creating step, an activity calculating step for obtaining an activity obtained by numerically indexing the vibration state at each time;
The activity obtained in the activity calculating step is the standard activity indicating the average value of the activity obtained in the time zone in which the slag does not flow out, the average of the molten metal flow rate obtained in the time zone in which the slag does not flow out. A corrected activity calculation step of calculating a corrected activity by correcting using a reference molten metal flow rate indicating a value and an activity estimation formula when the molten metal flow rate changes,
A slag outflow detection step of detecting slag outflow based on the corrected activity calculated in the correction activity calculation step ,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
And the constant C in the above equation is:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
The slag outflow detection method characterized by setting it as a constant . The activity estimation formula when the molten metal flow rate is changed used in the correction activity calculation step is estimated from the activity before the change in the same charge, the molten metal flow rate, and the molten metal flow rate after the change. Item 2. The slag outflow detection method according to Item 1. In the slag outflow detection step, when the average rate of change of the correction activity falls below a preset threshold, it is determined that the correction activity starts to decay, and further, the correction activity is determined to start as the slag outflow starts. The slag outflow detection method according to claim 1 or 2 , characterized by the above. After a lapse of a certain time from the slag outflow start time determined by the slag outflow detection method according to any one of claims 1 to 3, from the container containing the molten metal and slag, the sealed flow pipe is passed through. And stopping the injection of the molten metal into another container. 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 container through the sealed flow pipe. A slag outflow detection device for detecting
Vibration level measuring means for measuring a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe over time;
Delay vector creating means for creating a delay vector based on the vibration measurement signal measured by the vibration level measuring means;
On the reconstructed attractor drawn by the delay vector created by the delay vector creating means, an activity calculating means for obtaining an activity obtained by numerically indexing the vibration state at each time;
The activity obtained by the activity calculating means is a reference activity indicating an average value of activities obtained in a time zone in which slag does not flow out, an average of molten metal flow rates obtained in a time zone in which slag does not flow out. A corrected activity calculation means for calculating a corrected activity by correcting using a reference molten metal flow rate indicating a value and an activity estimation formula when the molten metal flow rate changes,
Slag outflow detection means for detecting slag outflow based on the corrected activity calculated by the corrected activity calculation means,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
The constant C in the above formula is expressed by the following relational expression:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
A slag outflow detection device characterized by having a constant in The activity estimation formula when the molten metal flow rate is changed used by the correction activity calculation means is estimated from the activity before the change in the same charge, the molten metal flow rate, and the molten metal flow rate after the change. Item 6. The slag outflow detection device according to Item 5 . The slag outflow detection means determines that the correction activity starts to decay when the average rate of change of the correction activity falls below a preset threshold, and further determines that the slag outflow starts with the start of attenuation of the correction activity. The slag outflow detection device according to claim 5 or 6 . After a lapse of a certain time from the slag outflow start time determined by the slag outflow detection device according to any one of claims 5 to 7, a container containing the molten metal and slag is passed through the sealed flow pipe. Then, the molten metal injection control device stops the injection of the molten metal into another container . 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 container through the sealed flow pipe. A program for causing a computer to execute a slag outflow detection method for detecting
A vibration level measuring step for measuring a vibration level in a one-dimensional, two-dimensional or three-dimensional direction generated in the sealed flow pipe over time;
A delay vector creating step of creating a delay vector based on the vibration measurement signal measured in the vibration level measuring step;
On the reconstructed attractor drawn by the delay vector created in the delay vector creating step, an activity calculating step for obtaining an activity obtained by numerically indexing the vibration state at each time;
The activity obtained in the activity calculating step is the standard activity indicating the average value of the activity obtained in the time zone in which the slag does not flow out, the average of the molten metal flow rate obtained in the time zone in which the slag does not flow out. A corrected activity calculation step of calculating a corrected activity by correcting using a reference molten metal flow rate indicating a value and an activity estimation formula when the molten metal flow rate changes,
A slag outflow detection step of detecting slag outflow based on the corrected activity calculated in the correction activity calculation step,
The corrected activity is expressed by the following equation:
Correction activity = activity / {reference activity × (molten metal flow rate / reference molten metal flow rate) ^C }
The constant C in the above formula is expressed by the following relational expression:
“Variable amount in charge of {log activity}” = C × “Variable amount in charge of {log molten metal flow rate}”
A program for causing a computer to execute a slag outflow detection method characterized by being a constant in the above. A computer-readable recording medium on which the program according to claim 9 is recorded.

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