JP2001219250A - Apparatus and method for controlling molten steel temperature in tundish, and computer-readable storage medium - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the accuracy of temperature control of molten steel in a tundish. A control unit (17) calculates a molten steel temperature (T (t + i)) in a tundish (2) at a sampling time point i, a current molten steel temperature (T (t)) in a tundish (2), and a plasma heating power amount of a main power supply (9). temporal change amount G _i · Delta] u of the molten steel temperature in the tundish 2 is predicted when changing, tundish predicted on the basis of the casting process, such as injection of the molten steel into the molten steel injection and mold 6 from ladle 1 The calculation prediction is performed using the molten steel temperature change amount ΔT _i in 2.
Then, from the predicted molten steel temperature T (t + i) and a preset target molten steel temperature r, an optimum plasma heating power change amount Δu of the main power supply 9 is calculated, and the plasma heating power change amount Δ is calculated.
By changing the plasma heating power of the main power supply 9 by u,
The temperature of molten steel in the tundish 2 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for controlling the temperature of molten steel in a tundish used in continuous casting, and a computer-readable storage medium.

[0002]

2. Description of the Related Art In order to obtain good quality cast slabs in continuous casting, it is desirable that the temperature of molten steel injected from a tundish into a mold is as low as possible without impairing casting. . On the other hand, when the temperature of the molten steel in the tundish becomes lower than a predetermined temperature, there occurs a problem that impurities cannot completely float or a nozzle for injecting the molten steel into a mold is blocked. For this reason, the temperature of the molten steel in the tundish is controlled within a predetermined temperature range.

A technique for controlling the temperature of molten steel in a tundish is disclosed in Japanese Patent No. 2910136, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent No. 40010 or the like. The second
Japanese Patent Publication No. 910136 discloses that fluctuations in the flow rate of molten steel and the accumulated amount of molten steel are reflected in controlling the temperature of molten steel in a tundish. Further, the above-mentioned Japanese Patent Application Laid-Open No. 7-400
No. 10 discloses a method for controlling the temperature of molten steel in a tundish,
It is disclosed that the throughput flow rate of molten steel injected into the mold is reflected.

[0004]

However, in each of the above-mentioned conventional examples, heating control is performed on the basis of the actually generated state (fluctuations in molten steel flow rate and molten steel accumulation quantity, and fluctuations in throughput flow rate). The heating control is executed after detecting the actually generated state. Therefore, a time delay is inevitably caused until the molten steel temperature is actually controlled, and this has been a cause that the molten steel temperature in the tundish cannot be controlled with high accuracy.

The present invention has been made to solve such a problem, and has as its object to improve the accuracy of controlling the temperature of molten steel in a tundish.

[0006]

According to the present invention, there is provided a controller for controlling the temperature of molten steel in a tundish, which controls heating means for heating molten steel in the tundish. A molten steel temperature predicting means for predicting a future molten steel temperature in the tundish; and a control for calculating an optimal control amount of the heating means from the future molten steel temperature predicted by the molten steel temperature predicting means and a preset target molten steel temperature. It is characterized in that it comprises an amount calculating means and a heating control means for controlling the heating means based on the optimum control amount of the heating means obtained by the control amount calculating means.

Another feature of the controller for controlling the temperature of molten steel in a tundish of the present invention is that the temperature of molten steel in the tundish is detected by a temperature detecting means for detecting the temperature of the molten steel in the tundish; A first molten steel temperature change amount estimating means for estimating a molten steel temperature change amount in the tundish, wherein the molten steel temperature estimating means comprises: a molten steel temperature in the tundish detected by the molten steel temperature detecting means; The point is that a future molten steel temperature in the tundish is predicted using the molten steel temperature variation in the tundish predicted by the first molten steel temperature variation prediction means.

[0008] Another feature of the control apparatus for controlling the temperature of molten steel in a tundish according to the present invention is that the first molten steel temperature variation estimating means includes a control parameter adapted to operating conditions and a control of the heating means. The point is to calculate the amount of temperature change of the molten steel in the tundish from the amount.

Another feature of the apparatus for controlling the temperature of molten steel in a tundish of the present invention is that the amount of molten steel in the tundish in the future, the future casting flow rate injected from the tundish into a mold, and the like. And a control parameter correcting means for correcting the control parameter according to the above.

[0010] Another feature of the apparatus for controlling the temperature of molten steel in a tundish of the present invention is a second molten steel temperature variation estimating means for estimating the molten steel temperature variation in the tundish based on a casting process. Wherein the molten steel temperature prediction means predicts a future molten steel temperature in the tundish further using the molten steel temperature change amount in the tundish predicted by the second molten steel temperature change amount prediction means. On the point.

Another feature of the control apparatus for controlling the temperature of molten steel in a tundish according to the present invention is that the second molten steel temperature change amount predicting means includes: In the early casting stage, the molten steel is injected from the ladle into the tundish and the molten steel is injected from the tundish into the mold, and the molten steel is injected from the ladle into the tundish. The point is that the amount of temperature change of the molten steel in the tundish is predicted by performing an operation corresponding to the last stage of casting in which only the molten steel is injected into the mold.

The method for controlling the temperature of molten steel in a tundish according to the present invention is a method for controlling the temperature of molten steel in a tundish for controlling heating means for heating the molten steel in the tundish. A process of predicting the molten steel temperature, a process of calculating the optimal control amount of the heating means from the predicted future molten steel temperature and a preset target molten steel temperature, and calculating the optimal control amount of the heating means. And a process of controlling the heating means on the basis of the above.

A computer-readable storage medium according to the present invention is characterized in that a program for causing the above-described units to function or a program for executing the above-described processes is stored in a computer-readable manner.

According to the present invention as described above, it is possible to predict the future molten steel temperature in the tundish and obtain an optimal control amount that brings the predicted molten steel temperature closer to the target molten steel temperature. By controlling the heating means based on the control amount, it is possible to improve the accuracy of controlling the temperature of the molten steel in the tundish.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a control device and method for a molten steel temperature in a tundish according to the present invention; FIG. 1 shows the configuration of a continuous casting facility. In FIG. 1, reference numeral 1 denotes a ladle (a ladle). In a continuous casting facility, molten steel melted in a steelmaking furnace (not shown) is transported by the ladle 1.

Reference numeral 2 denotes a tundish. The molten steel transported by the ladle 1 is once injected into the tundish 2. The interior of the tundish 2 is divided into three chambers, an injection chamber 3, a heating chamber 4, and a casting chamber 5, which communicate with each other.

Reference numeral 6 denotes a mold. The molten steel in the tundish 2 is injected into the mold 6 while controlling the flow rate.

Reference numeral 7 denotes a plasma torch, which is installed above the heating chamber 4 of the tundish 2. Reference numeral 8 denotes a furnace bottom electrode, which is provided at the bottom of the heating chamber 4 of the tundish 2. Reference numeral 9 denotes a main power supply, which controls the plasma heating power of the main power supply 9 to generate a plasma arc in the plasma torch 7 and heat the molten steel in the tundish 2.

Reference numeral 10 denotes a molten steel temperature detector which detects a molten steel temperature T in the tundish 2. Reference numeral 11 denotes a target molten steel temperature setting section, in which a target molten steel temperature r in the tundish 2 is set.

Reference numeral 12 denotes a casting flow rate detector, which is a casting flow rate F of molten steel injected into the mold 6 from the tundish 2.
T is detected. The casting flow rate FT is normally kept constant according to the casting schedule, but there are some fluctuations in the actual flow rate, and sometimes the flow rate is intentionally changed during casting. ing. 1
Reference numeral 3 denotes a ladle molten steel amount detector which detects the molten steel amount WL in the ladle 1. Reference numeral 14 denotes a tundish molten steel amount detector which detects the amount of molten steel WT in the tundish 2.

Reference numeral 15 denotes a casting schedule setting section for setting a casting schedule. When performing the casting operation by replacing the ladle 1 (continuous-continuous casting operation), the casting schedule setting unit 15 sets the time Δt until the start of the next charge,
The next charge ladle molten steel amount WLn ₀ and the next charge scheduled molten steel flow rate FLn are provided to the calculation unit 16.

Reference numeral 16 denotes an arithmetic unit, which will be described in detail later. The molten steel flow rate FL, the molten steel amount WL in the ladle 1, the molten steel amount WT in the tundish 2, the time Δt until the start of the next charge, the next charge ladle molten steel the amount WLn _0, performs calculation based on the following charge schedule molten steel flow FLn, provides control parameters G _i and the molten steel temperature variation [Delta] T _i to the control unit 17.

Reference numeral 17 denotes a control unit, which will be described in detail later. The molten steel temperature T in the tundish 2 detected by the molten steel temperature detector 10, the target molten steel temperature r preset by the target molten steel temperature setting unit 11, A future molten steel temperature in the tundish 2 is predicted using the control parameter G _i and the molten steel temperature change amount ΔT _i calculated by the calculation unit 16, and an optimum plasma heating power change amount Δu of the main power source 9 is obtained. . Then, the plasma heating power of the main power supply 9 is changed by the plasma heating power change amount Δu to control the temperature of the molten steel in the tundish 2.

Next, the casting operation in the continuous casting facility of the present embodiment configured as described above will be described. Molten steel produced in a steelmaking furnace (not shown) is transported by the ladle 1.

The molten steel transported by the ladle 1 is injected into a tundish 2. At this time, the injection of molten steel from the tundish 2 into the mold 6 has not been started yet, and as shown in a period a of FIG. 2, the amount of molten steel WT in the tundish 2 increases (early casting).

When molten steel is injected from the ladle 1 and the amount of molten steel WT in the tundish 2 reaches a predetermined amount, the injection of molten steel from the tundish 2 into the mold 6 is started.
In this case, assuming that molten steel is injected from ladle 1 to tundish 2 at a molten steel flow rate FL, casting flow rate FT of molten steel injected from tundish 2 to mold 6
Is set equal to the molten steel flow rate FL. Therefore, as shown in period b of FIG.
The amount of molten steel WT is kept almost constant (middle casting period (at the time of steady casting)).

The molten steel injected from the tundish 2 is quenched by contact with the water-cooled mold 6, and then gradually loses heat and solidification proceeds.

When the molten steel in the ladle 1 runs out, only the molten steel is injected from the tundish 2 into the mold 6, so that the amount of molten steel WT in the tundish 2 decreases as shown in period c in FIG. End of casting).

If the continuous-continuous casting operation is to be performed, the ladle 1 is moved from the ladle 1 with an appropriate amount of molten steel left in the tundish 2 based on the casting schedule set in the casting schedule setting section 15. The injection of molten steel into 2 is stopped once. And after a while,
The injection of molten steel from the ladle 1 into the tundish 2 is started (start of next charge), and the molten steel is injected into the mold 6 in an amount larger than the molten steel injection amount until the molten steel amount WT in the tundish 2 reaches a predetermined amount. The molten steel is injected into the tundish 2 from the ladle 1 in an amount (period d in FIG. 2). As a result, the above-described initial casting, intermediate casting, and final casting are repeated.

Hereinafter, the control of the temperature of the molten steel in the tundish 2 according to the present embodiment will be described. First, the concept underlying the control of the temperature of molten steel in the tundish 2 will be described. In the present embodiment, the molten steel temperature T in the tundish 2 at a sampling time point i after a certain time point t.
(t + i) is, T (t + i) = T (t) + G i · Δu + ΔT i ... formula (a) T (t): temperature of molten steel at time t G _i: control parameter Delta] u: plasma heating power change amount [Delta] T _i: It is to be obtained from a temperature prediction model that defines the temperature change of molten steel based on the casting process.

In the temperature prediction model of the above equation (a),
T (t) is a term representing the molten steel temperature in the tundish 2 at the present time (time t).

In the temperature prediction model of the above equation (a),
G _i · Delta] u is the time variation amount of the molten steel temperature in the tundish 2 is predicted when changing only Delta] u plasma heating power of the main power source 9, i.e., the prediction on the basis of the control amount of the plasma torch 7 This is a term representing the amount of change in the temperature of the molten steel in the tundish 2.

[0033] Here will be described the control parameter G _i. With the casting flow rate of the molten steel injected from the tundish 2 into the mold 6 kept at the reference casting flow rate FT ⁰ , and the molten steel amount in the tundish 2 kept at the reference molten steel amount WT ⁰ , the plasma heating power is reduced by a unit amount. If you change it,
Temporal change amount of the molten steel temperature in the tundish 2 is to be given by the step response G _i ^0. That is, as shown in FIG. 3, when the amount of plasma heating electric power is changed by a unit amount and the time elapses to 0, 1, 2, 3,..., The temporal change amount of the molten steel temperature in the tundish 2 Step response G to represent
_i ^{0, _{respectively, G 0 0, G 1 0}} , G 2 0, G 3 0, ... become.

In this embodiment, the previously obtained step response G _i ⁰ is added to the casting flow rate FT (t + i) at the i-th sampling time and the molten steel amount WT (t + i) in the tundish 2 at the i-sampling time. determining the control parameter G _i by performing the correction using the. That is, defining the ^{_{G i = (FT 0 · WT}} 0 / FT (t + i) · WT (t + i)) · G i 0 ... control parameter G _i by the expression (b). Thus, it is possible to obtain a control parameter G _i to suit the operating conditions such as amount of molten steel casting flow rate and tank in the dish 2.

Since the casting flow rate FT of molten steel injected from the tundish 2 into the mold 6 is usually set to be constant, it is necessary to know the casting flow rate FT (t + i) at the i sampling time. Is possible.

Further, at the time of steady casting, since the molten steel amount WT in the tundish 2 is kept substantially constant as described above, the current molten steel amount WT (t) is set as the molten steel amount WT (t + i) at the i-th sampling time. May be used. In addition, the molten steel amount WT in the tundish 2 changes as described above at the beginning of casting and at the end of casting, but the amount of the change is known from the casting flow rate FL and the like.
It is also possible to obtain (t + i).

In the temperature prediction model of the above equation (a),
ΔT _i is a term representing the amount of change in the temperature of the molten steel in the tundish 2 predicted based on a casting process such as injection of molten steel from the ladle 1 and injection of molten steel into the mold 6. This ΔT _i is obtained by ΔT _i = ΣΔT _k (k is 0 to _i ), and ΔT _k can be defined as ΔT _k = T (t + k) −T (t + k−1).

Here, in the early stage of casting, although the natural temperature is lowered, high temperature molten steel is injected from the ladle 1 into the tundish 2 as described above, and the amount of molten steel WT in the tundish 2 increases. The temperature of the molten steel in the tundish 2 tends to increase. Therefore, at the beginning of casting, ΔT _k = E (≧ 0) (c). E is a constant determined by casting conditions and the like.

In the middle stage of casting (at the time of steady casting), the amount of molten steel WT in the tundish 2 is kept substantially constant as described above, and a natural temperature drop occurs. Also,
It is also necessary to consider the temperature of the molten steel injected from the ladle 1 to the tundish 2, and the temperature of the molten steel is
It changes in accordance with the amount of molten steel WL. Therefore, taking these factors into account, in the middle stage of casting (during steady casting), ΔT _k = A + B / WL (t + k) (d). Note that A and B are constants determined by casting conditions and the like.

At the end of casting, the natural temperature continues to decrease in the tundish 2, and the molten steel amount WT in the tundish 2 decreases as described above, and the molten steel temperature changes accordingly. Therefore, taking these factors into account, at the end of casting, ΔT _k = C + D / WT (t + k) (e). Note that C and D are constants determined by casting conditions and the like.

As described above, based on the temperature prediction model represented by the equation (a), the molten steel temperature T
If (t + i) can be calculated, the optimum plasma heating power change amount Δ can be calculated from the predicted molten steel temperature T (t + i) and the target molten steel temperature r.
u can be determined.

In the present embodiment, an evaluation function J shown in Equation 1 is defined to determine the optimum amount of change in plasma heating power Δu.

[0043]

(Equation 1)

The predicted window time lower limit N1 and the predicted window time upper limit N2 are future times, for example, 30 seconds after N1.
N2 is set to be 120 seconds later.

Then, the plasma heating power change amount Δu that minimizes the evaluation function J is set as an optimal control amount. Solving the plasma heating power change amount Δu that minimizes the evaluation function J yields the result shown in Expression 2.

[0046]

(Equation 2)

In order to solve the plasma heating power change amount Δu, which is the optimum control amount, the details are omitted, but the evaluation function J is partially differentiated with respect to the plasma heating power change amount Δu.
What is necessary is just to find the plasma heating power change amount Δu at which it becomes zero.

Next, the operation of controlling the temperature of the molten steel in the tundish 2 according to the present embodiment will be described based on the concept described above. The arithmetic unit 16 receives the molten steel flow rate FL (t) from the molten steel flow rate detector 12, the molten steel quantity WL (t) in the ladle 1 from the ladle molten steel quantity detector 13, and the tundish molten steel quantity detector 14 from the tundish molten steel quantity detector 14. WT (t) is input. Also, the casting schedule setting unit 15 outputs a time Δt until the next charge starts,
The next charge ladle molten steel amount WLn ₀ and the next charge scheduled molten steel flow rate FLn are input.

Since the ladle molten steel amount detector 13 has a maximum ladle molten steel amount WL of about several hundred tons, it is not practical to directly measure it. Therefore, it may be calculated.

For example, in the early stage of casting, tundish 2
There is no injection of molten steel from
Is the initial value WL _{0 of the} ladle molten steel amount.
The amount of molten steel WT (t) in the tundish 2 may be subtracted from the above equation. That is, WL (t) = WL ₀ −WT (t).

After the injection of the molten steel from the tundish 2 into the mold 6 is started, the molten steel amount WL (t) in the ladle 1 is equal to the previously obtained molten steel amount WL in the ladle 1.
What is necessary is to subtract the amount of molten steel injected into the tundish 2 during the time (t-t ') from (t'). That is, WL (t) = WL (t ′) − FL · (t−t ′).

The arithmetic unit 16 calculates the input molten steel flow rate FL (t), the molten steel amount WL (t) in the ladle 1, the molten steel amount WT (t) in the tundish 2, the time Δt until the next charge start, next charge ladle of molten steel amount WLn _0, using the following charge schedule molten steel flow FLn, acquires the control parameter G _i as explained in the above formula (b), also in the above formula (c) ~ (e) As described, the temperature change of molten steel ΔT _i
To get. In the present embodiment, the calculation unit 16
Corresponds to the control parameter correcting means and the second molten steel temperature change amount predicting means according to the present invention.

Then, the control parameter G _i and the molten steel temperature change amount ΔT _i are input from the calculation unit 16 to the control unit 17. From the temperature detector 10, the current molten steel temperature T (t) in the tundish 2 is supplied to the target molten steel temperature setting section 11.
, A preset target molten steel temperature r is input to the control unit 17.

[0054] The control unit 17, the control parameter is the input G _i and the molten steel temperature variation [Delta] T _i, tundish 2
As described above, using the molten steel temperature T (t) and the target molten steel temperature r, the molten steel temperature T (t + i) at the i-th sampling time point is obtained by the temperature prediction model, and the optimum control amount is obtained by the evaluation function J. The plasma heating power change amount Δu is calculated. Then, by changing the plasma heating power of the main power supply 9 by the plasma heating power change amount Δu, it is possible to control the molten steel temperature in the tundish 2 to be the target molten steel temperature r. In the present embodiment,
The control unit 17 corresponds to the molten steel temperature estimating means, control amount calculating means, heating control means, and first molten steel temperature change amount estimating means according to the present invention.

When the casting schedule is changed in the course of a series of casting operations (for example, the molten steel flow rate FL or the casting flow rate FT is changed in the middle), the casting schedule is stored in the casting schedule setting section 15. By setting, the control parameter G _i and the molten steel temperature change amount ΔT _i are obtained, and the plasma heating power change amount Δu that becomes the optimum control amount is obtained.
Can be obtained.

As described above, according to the apparatus for controlling the temperature of molten steel in the tundish of the present embodiment, the temperature of the molten steel in the future is predicted in accordance with the variation of the molten steel flow rate and the accumulated amount of molten steel, the variation of the throughput flow rate, and the like. In addition, it is possible to control the temperature of the molten steel to compensate for the temperature change due to the fluctuation.

Note that means for supplying a computer with software program codes for realizing the functions of the above-described embodiments, for example, a storage medium storing such program codes are included in the scope of the present invention.

[0058]

As described above, according to the present invention, the heating means is controlled by predicting the temperature of the molten steel in the future in accordance with the fluctuations in the flow rate of the molten steel and the accumulated amount of the molten steel, the fluctuations in the throughput flow rate, and the like. Control of the molten steel temperature that compensates for the temperature change caused by the pressure. Thereby, the accuracy of molten steel temperature control can be improved without a time delay. Therefore, it is possible to stabilize the temperature of the molten steel in the tundish and obtain a cast of good quality.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a continuous casting facility.

FIG. 2 is a diagram showing a relationship between time and a molten steel amount WT in a tundish 2;

FIG. 3 is a diagram illustrating a temporal change amount of molten steel temperature in a tundish 2 when a plasma heating power amount is changed by a unit amount.

[Explanation of symbols]

 Reference Signs List 1 ladle (ladle) 2 tundish 3 pouring chamber 4 heating chamber 5 pouring chamber 6 mold (mold) 7 plasma torch 8 furnace bottom electrode 9 main power supply 10 molten steel temperature detector 11 target molten steel temperature setting section 12 molten steel flow rate detector 13 Ladle molten steel amount detector 14 Tundish molten steel amount detector 15 Casting schedule setting unit 16 Operation unit 17 Control unit

Continuation of the front page (72) Inventor Tadahiro Izu 3434 Shimada, Hikari-shi F-term in Nippon Steel Corporation Hikari Works (reference) 4E004 MB20 4E014 AA01 EA01

Claims (9)

[Claims] An apparatus for controlling a temperature of molten steel in a tundish for controlling a heating means for heating molten steel in the tundish, comprising: a molten steel temperature predicting means for predicting a future molten steel temperature in the tundish; Control amount calculating means for calculating an optimal control amount of the heating means from a future molten steel temperature predicted by the molten steel temperature predicting means and a preset target molten steel temperature; and a heating amount of the heating means obtained by the control amount calculating means. And a heating control means for controlling the heating means based on the optimum control amount. 2. A molten steel temperature detecting means for detecting a molten steel temperature in the tundish, and a first molten steel temperature change estimating means for estimating a molten steel temperature change in the tundish based on a control amount of the heating means. The molten steel temperature predicting means comprises: a molten steel temperature in the tundish detected by the molten steel temperature detecting means; and a molten steel temperature in the tundish predicted by the first molten steel temperature change amount predicting means. The control device for a molten steel temperature in a tundish according to claim 1, wherein a future molten steel temperature in the tundish is predicted using the change amount. 3. The first molten steel temperature change amount predicting means,
3. The control device for controlling the temperature of molten steel in a tundish according to claim 2, wherein the amount of change in the temperature of molten steel in the tundish is calculated from a control parameter adjusted to operating conditions and a control amount of the heating means. 4. A control parameter correcting means for correcting the control parameter according to a future molten steel amount in the tundish and a future casting flow rate injected from the tundish into a mold. Claim 3
3. The control device for molten steel temperature in a tundish according to 1.). 5. A second molten steel temperature change predicting means for predicting a molten steel temperature change in the tundish based on a casting process, wherein the second molten steel temperature predicting means comprises a second molten steel temperature change predicting means. 3. The control device for a molten steel temperature in a tundish according to claim 2, wherein a future molten steel temperature in the tundish is predicted further using the amount of change in the molten steel temperature in the tundish predicted by the method. 6. The second molten steel temperature change amount predicting means,
As the casting process, the casting early to inject molten steel from the ladle to the tundish, the middle of casting to inject the molten steel from the ladle to the tundish and to inject the molten steel from the tundish to the mold,
Performing an operation corresponding to the end of casting in which the molten steel is not injected from the ladle into the tundish and only the molten steel is injected from the tundish into the mold, and predicting a molten steel temperature change amount in the tundish. The control device for a molten steel temperature in a tundish according to claim 5, characterized in that: 7. A method for controlling the temperature of molten steel in a tundish for controlling heating means for heating molten steel in the tundish, comprising: a process for predicting a future molten steel temperature in the tundish; A process of calculating an optimal control amount of the heating means from a future molten steel temperature and a preset target molten steel temperature; anda process of controlling the heating means based on the calculated optimal control amount of the heating means. A method for controlling the temperature of molten steel in a tundish, comprising: 8. A computer-readable storage medium storing a computer-readable program for causing each of the means according to claim 1 to function. 9. A computer-readable storage medium storing a program for executing each processing according to claim 7 in a computer-readable manner.