JP4727431B2 - Method for operating steel manufacturing process and operating device used therefor - Google Patents

Description

  The present invention relates to a steel making process of steel that transports molten steel after molten steel treatment in a ladle, pours the molten steel directly or through a tundish into a mold, and cools the slab by cooling. Specifically, the present invention relates to an operation method of an iron and steel manufacturing process and an operation apparatus used therefor.

  The steel manufacturing process is generally operated in the following manner.

  That is, the molten steel processed by an appropriate molten steel processing apparatus (for example, RH type vacuum degassing apparatus, etc.) provided in the molten steel processing facility is converted into an appropriate ladle conveying means (for example, a crane or ladle trolley (dedicated railroad). )), Each ladle is sequentially transported to a continuous casting facility.

  And the molten steel conveyed to the said continuous casting installation is poured into a casting_mold | template via the tundish with which the continuous casting machine (henceforth a continuous casting machine) provided in the said continuous casting installation is equipped. . In addition, when the continuous casting machine does not include a tundish, the molten steel is poured directly into the mold. Hereinafter, unless otherwise specified, the molten steel is described as being poured into a mold through a tundish.

  The molten steel poured into the mold is pulled out while being cooled by appropriate cooling means (including the mold) so that slabs such as so-called slabs, blooms and billets are continuously cast. It has become.

  In the continuous casting, the following first to third casting conditions are important.

The first casting condition is to maintain a temperature at which the molten steel in the ladle is poured into a mold (hereinafter also simply referred to as a pouring temperature) at a predetermined temperature.
The second is that the pouring temperature does not exceed the upper limit value of a suitable temperature range (hereinafter simply referred to as pouring temperature range) of molten steel when pouring into a mold.
3rd is that the said pouring temperature is not less than the lower limit of the said pouring temperature range.
The pouring temperature range is, for example, 1550 to 1570 [° C.], which is extremely narrow.

  The reason why the second and third casting conditions are important will be described below.

(Second casting condition)
Suppose that the pouring temperature exceeds the upper limit of the pouring temperature range.
In this case, there is a possibility that the solidified shell (hereinafter also simply referred to as a shell) may be pulled out of the mold before growing to a predetermined thickness. This causes various problems such as deterioration of the surface quality of the slab and so-called breakout. Breakout means that the shell is locally broken by the pressing force of the slab conveying roll provided in the continuous casting machine, and molten steel in the shell that has not yet solidified leaks to the outside of the shell. It is a bug.
Due to the above circumstances, an appropriate upper limit value is provided for the pouring temperature, and it is important that the pouring temperature is not more than the upper limit value.

(Third casting conditions)
On the other hand, suppose that the pouring temperature has fallen below the lower limit of the pouring temperature range.
In this case, the molten steel is solidified in the tundish provided in the continuous casting machine or in the immersion nozzle as a pouring guide means for smoothly pouring the molten steel from the tundish to the mold, and the solidified product is immersed in the immersion. This causes various problems such as clogging of the nozzle.
Due to the above circumstances, an appropriate lower limit is provided for the pouring temperature, and it is important that the pouring temperature be equal to or higher than the lower limit.

In order to satisfy the first to third casting conditions, the molten steel treatment has been conventionally performed by the following method.
That is, the temperature drop of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold is predicted, and the molten steel temperature of the molten steel in the ladle at the end of the molten steel treatment (hereinafter simply referred to as treatment). The molten steel treatment is performed such that the end temperature is also a temperature obtained by adding the predetermined temperature according to the first casting condition to the predicted temperature drop width (hereinafter also simply referred to as the predicted temperature drop width). It was done.

The temperature drop width is predicted by various methods such as statistical processing, temperature calculation, and neuro model, or by the intuition of a molten steel processing operator. Factors are considered.
-Temperature change of ladle and tundish refractories, change in shape of refractory that melts with use, physical properties of refractories, etc.
-Ladle transport schedule and ladle and tundish processing schedule, for example, empty time of the ladle, heating time of the empty ladle by appropriate heating means, and end of molten steel processing Time from the start of pouring to the mold.
-Components of molten steel and slag in the ladle, such as carbon content and various alloy contents.
-It is the processing conditions of the molten steel by the said molten steel processing apparatus, Comprising: For example, the temperature rising amount of molten steel, processing time, the stirring method, and the input amount of the scrap which has the cooling effect with respect to molten steel.
・ Measured value of molten steel temperature, for example, when steel is discharged from a converter or during molten steel processing.
・ The amount of bullion attached to the inner wall of the ladle.
In addition, it may be predicted by referring to a correspondence table (so-called table) between the above-described factors and the temperature drop width created based on information obtained from experience.

Moreover, the said process completion temperature is adjusted during the molten steel process with the following method.
That is, in order to raise the molten steel temperature, so-called Al temperature raising is performed in which Al is introduced into the molten steel during the molten steel treatment.
On the other hand, in order to lower the molten steel temperature, so-called scrap cooling is similarly performed in which scrap is put into the molten steel.

  However, in practice, it has not always been successful to adjust the processing end temperature to satisfy the first to third casting conditions.

  This is because it is extremely difficult to predict and measure the temperature of refractories in ladle and tundish, and the ladle transport schedule and actual schedule when the temperature drop is predicted. This is because the temperature drop width could not be accurately predicted because there are cases where the transportation schedules of the above are greatly different.

  Needless to say, techniques aimed at improving the accuracy of the predicted temperature drop have been studied many times. However, as described above, the accuracy of the predicted temperature drop width inevitably has a limit as long as the actual transfer schedule may be greatly different from that predicted.

As this type of technology, for example, in Patent Document 1, the temperature drop amount of the molten metal from the start of out-of-furnace refining to the start of casting is calculated based on the operation schedule, and the required casting temperature is calculated. It is used to calculate the target temperature of the molten metal at the start of out-of-furnace refining, and compare the obtained target temperature with the actually measured actual temperature to adjust the temperature of the molten metal. According to this, even if the schedule of the casting apparatus is changed after the end of blowing (treatment in the converter), the molten metal satisfying the casting required temperature can be supplied to the casting apparatus.
JP-A-11-335721

  However, in Patent Document 1, when the operation schedule is changed after the molten steel processing is completed, it is not always possible to supply the molten metal that satisfies the required casting temperature to the casting apparatus.

Therefore, conventionally, the continuous casting operator as the operator of the continuous casting equipment actually measures the pouring temperature, and when the measurement result does not satisfy the first to third casting conditions, In order to reduce production problems as much as possible, we responded by quickly changing the operation method of the continuous casting machine.
Specifically, if the pouring temperature is above the upper limit of the pouring temperature range, as a result, the productivity will be deteriorated, depending on the degree to which it has exceeded, This has been dealt with by reducing the casting speed or delaying the start-up of the continuous casting machine if it is started.
On the other hand, when the pouring temperature is below the lower limit value of the pouring temperature range, the casting speed is increased according to the degree of the pouring temperature range, and if the tundish has an appropriate molten steel heating means. For example, it has been dealt with by raising the temperature of the molten steel by the molten steel heating means.

However, as described above, it is possible to cope with a sudden change in the operation method of the continuous casting machine only when the first to third casting conditions cannot be satisfied a little, and the breakout and the clogging of the immersion nozzle described above are possible. When this occurs, almost no countermeasures have been taken, and casting must be stopped and materials discarded.
Moreover, it is known that suddenly changing the operation method such as the casting speed in a short time will adversely affect the surface quality of the slab.

  Therefore, there has been a need for a technique that can reliably satisfy the first to third casting conditions.

  Therefore, the inventors of the present invention have paid attention to the following items as a result of intensive studies.

  (A) That is, the first casting condition is less important in terms of operation and slab quality than the second and third casting conditions. In other words, it is not always necessary to maintain the pouring temperature at a predetermined temperature as the first casting condition, and it is sufficient to be within the pouring temperature range described as the second and third casting conditions. is there.

  (B) Although it is certainly important to improve the accuracy of the predicted temperature drop width, it is more important to accurately grasp the variation in the predicted temperature drop width.

  (C) Specifically, it is important that the pouring temperature is within the pouring temperature range in consideration of variations in the predicted temperature drop width.

  (D) Moreover, when it is judged that it is difficult to make the said pouring temperature into the said pouring temperature range after considering said (A)-(C), from an operational side It is important to determine the processing end temperature.

  Hereinafter, the items (A) to (C) will be briefly described with reference to the drawings.

  FIG.1 and FIG.2 represents the shift | offset | difference with respect to the target value of the pouring temperature of molten steel, and its frequency. In the figure, “predetermined temperature (1)” is a predetermined temperature (hereinafter also referred to simply as “predetermined temperature”) as the first casting condition. ) "Is the pouring temperature range described as the second and third casting conditions.

  FIG. 1 is a reference example in which a processing end temperature determined by a conventional method is adopted. As shown in the figure, the predicted temperature drop width includes variations due to various factors, and therefore, the pouring temperature cannot always be set to a predetermined temperature (Reference Test 1). Further, depending on the degree of variation, it may exceed the upper limit value of the pouring temperature range (reference test 2), or may be lower than the lower limit value (reference test 3).

When the items (A) to (C) are applied to this figure, the following can be said.
That is, it is not always necessary that the pouring temperature having a variation as in Reference Tests 1 to 3 has the highest frequency at the predetermined temperature (1). The pouring temperature is always higher than the pouring temperature. It can be said that it is important to be within the range (from viewpoint A).
In addition, it is important to make the accuracy of the predicted temperature drop width as good as possible as in Reference Test 1, in other words, to make the variation in the pouring temperature as narrow as possible. It can be said that it is more important to grasp accurately (quantitatively) (from viewpoint B).
And it can be said that it is important that the pouring temperature is within the pouring temperature range in consideration of the variation of the predicted temperature drop width (from the viewpoint C).

On the other hand, FIG. 2 is an example in which the processing end temperature determined by the method according to the present invention is adopted. This drawing does not limit the technical significance or technical scope of the present invention at all, but is merely created for convenience of explanation.
As shown in this figure, the accuracy of the predicted temperature drop width is improved by appropriately raising and lowering the pouring temperature, which is the most frequent among the pouring temperatures with variations, without necessarily matching the predetermined temperature. Although not improved, the pouring temperature can be almost always within the pouring temperature range (Tests 10 to 12).

  The present invention has been made in view of such various points, and its main object is to provide a steel manufacturing process that can make the pouring temperature within a preferable temperature range while considering variations in the pouring temperature. The object is to provide an operation method and an operation apparatus used therefor.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

Predict the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold.
The maximum temperature-side variation width (ΔTdu: [° C.]) and the low-temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
The molten steel processing equipment is operated so that the processing end temperature (Th1: [° C.]) of the molten steel in the ladle as the molten steel temperature at the end of the molten steel processing simultaneously satisfies the following formulas (1) and (2).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
However, Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold, and Tcmin [° C.] is the lower limit value of the pouring temperature range. , T represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.

  Thereby, the pouring temperature as the temperature at the time of pouring the molten steel in the ladle into the mold can be surely set within the pouring temperature range.

Predict the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold.
The maximum temperature-side variation width (ΔTdu: [° C.]) and the low-temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
When the treatment end temperature (Th1: [° C]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle that satisfies the following formulas (1) and (2) is not present, the treatment ends The molten steel processing facility is operated so that the temperature satisfies the following formula (3).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
Th1 = Tcmin + ΔTd (t) + ΔTdd (t) (3)
However, Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold, and Tcmin [° C.] is the lower limit value of the pouring temperature range. , T represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.

  This ensures that the pouring temperature is less than the lower limit value of the pouring temperature range while suppressing the maximum temperature range where the pouring temperature may exceed the upper limit value of the pouring temperature range as much as possible. it can. Therefore, continuous casting can be continued without problems.

Predict the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold.
The maximum temperature-side variation width (ΔTdu: [° C.]) and the low-temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
When the treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle that satisfies the following formulas (1) and (2) does not exist, When pouring the molten steel in the pan into the mold through a tundish equipped with appropriate molten steel heating means, the molten steel processing equipment is operated so that the processing end temperature satisfies the following formula (4).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
Th1 = Tcmax + ΔTd (t) −ΔTdu (t) (4)
However, Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold, and Tcmin [° C.] is the lower limit value of the pouring temperature range. , T represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.

  Thus, it is possible to reliably avoid the pouring temperature from exceeding the upper limit value of the pouring temperature range, while the pouring temperature does not fall below the lower limit value of the pouring temperature range. Can compensate. Therefore, continuous casting can be continued without problems.

Predict the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold.
The maximum temperature-side variation width (ΔTdu: [° C.]) and the low-temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
When the treatment end temperature (Th1 [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle that satisfies the following formulas (1) and (2) is not present, the treatment end temperature Operates the molten steel processing equipment so that the following formula (5) is satisfied.
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
MAX (Th1−ΔTd (t) + ΔTdu (t) −Tcmax) −
MAX (Tcmin− (Th1−ΔTd (t) −ΔTdd (t))) = 0 (5)
However, Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold, and Tcmin [° C.] is the lower limit value of the pouring temperature range. , T represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold until the point when pouring is finished, and MAX (x (t)) is x (t) It represents the maximum value of.

  As a result, the maximum temperature range in which the pouring temperature may exceed the upper limit value of the pouring temperature range and the maximum temperature range in which the pouring temperature may also be lower than the lower limit value substantially coincide with each other. The probability of being within the pouring temperature range can be improved as much as possible.

The molten steel processing operator as the operator of the molten steel processing equipment is the maximum that may exceed the upper limit value of the processing end temperature and the pouring temperature range for the continuous casting operator as the operator of the continuous casting equipment. The temperature range and / or the maximum temperature range that may fall below the lower limit value are notified in advance.
In addition, the “in advance” in the above “notify in advance” specifically means “at least before the molten steel of the corresponding charge is poured into the mold”, and unless otherwise specified, The same shall apply in the specification.

Thereby, the continuous casting operator can grasp in advance each information on the temperature of the molten steel, so the continuous casting operator determines that it is necessary to change the casting conditions or to change the pouring start time. Can be dealt with without any problems.
The “pouring start time” is the time when molten steel is first poured into a mold when continuous casting is started.

  The molten steel processing operator as the operator of the molten steel processing equipment, to the continuous casting operator as the operator of the continuous casting equipment, poured the molten steel into the mold first when starting the continuous casting speed and continuous casting. At least one of the pouring start time as the start time is instructed in advance.

That is, it is difficult for the continuous casting operator to change the continuous casting speed and the pouring start time in a short time unless there is an instruction in advance due to operational circumstances.
Therefore, as described above, the molten steel processing operator gives an appropriate continuous casting speed or pouring start time to the continuous casting operator in advance, and the continuous casting operator changes them with a margin. can do.

  The molten steel processing operator as the operator of the molten steel processing equipment, to the continuous casting operator as the operator of the continuous casting equipment, poured the molten steel into the mold first when starting the continuous casting speed and continuous casting. At least one of a pouring start time as a start time and a heating condition for the molten steel by the molten steel heating means is instructed in advance.

That is, due to operational circumstances, unless otherwise instructed in advance, it is difficult for the continuous casting operator to change the continuous casting speed, the pouring start time, and the heating conditions for the molten steel of the molten steel heating means in a short time.
Therefore, as described above, the molten steel processing operator instructs the continuous casting operator in advance an appropriate continuous casting speed or a pouring start time, and heating conditions for the molten steel of the molten steel heating means, whereby the continuous casting is performed. Operators can change these with ease.

The treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle is measured.
The temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold is predicted.
The maximum temperature-side variation width (ΔTdu: [° C.]) and the low-temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
When at least one of the following formulas (6) and (7) is not satisfied, the molten steel processing operator as the operator of the molten steel processing facility is directed to the continuous casting operator as the operator of the continuous casting facility. The operating conditions of the continuous casting equipment are instructed in advance.
Th1−ΔTd (t) + ΔTdu (t) ≦ Tcmax (6)
Th1-ΔTd (t) −ΔTdu (t) ≧ Tcmin (7)
However, Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold, and Tcmin [° C.] is the lower limit value of the pouring temperature range. , T represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.

That is, it is difficult for the continuous casting operator to change the operating conditions of the continuous casting facility in a short time unless there is an instruction in advance due to operational circumstances.
Therefore, as described above, the molten steel processing operator instructs the continuous casting operator in advance with appropriate operating conditions of the continuous casting equipment, and the continuous casting operator changes this with sufficient margin. be able to.

  The operating conditions of the continuous casting equipment that the molten steel processing operator instructs to the continuous casting operator in advance are the continuous casting speed and the time when the molten steel is first poured into the mold when starting the continuous casting. And at least one of the pouring start time.

That is, it is difficult for the continuous casting operator to change the continuous casting speed and the pouring start time in a short time unless there is an instruction in advance due to operational circumstances.
Therefore, as described above, the molten steel processing operator gives an appropriate continuous casting speed and pouring start time to the continuous casting operator in advance, and the continuous casting operator changes them with a margin. can do.

  When the formula (7) is not satisfied, and the molten steel in the ladle is poured into a mold through a tundish equipped with appropriate molten steel heating means, the molten steel processing operator performs the continuous casting. The operating conditions of the continuous casting equipment instructed in advance to the operator are the continuous casting speed, the pouring start time as the time when the molten steel is first poured into the mold when starting the continuous casting, At least one of the heating conditions for the molten steel by the molten steel heating means.

That is, due to operational circumstances, unless otherwise instructed in advance, it is difficult for the continuous casting operator to change the continuous casting speed, the pouring start time, and the heating conditions for the molten steel of the molten steel heating means in a short time.
Thus, as described above, the molten steel processing operator instructs the continuous casting operator in advance an appropriate continuous casting speed, a pouring start time, and a heating condition for the molten steel of the molten steel heating means, so that the continuous casting is performed. Operators can change these with ease.

Provided is an operating device used in a steel manufacturing process configured as follows.
That is, based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1st prediction means.
Based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C]) and the low temperature side maximum variation width (ΔTdd (t): [° C]) of the temperature drop width can be predicted. 2nd prediction means.
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle still in the process of molten steel,
Even if the high temperature side maximum variation width is taken into account, the molten steel does not exceed the upper limit as the temperature when pouring into the mold, the molten steel in the ladle at the end of the molten steel treatment The upper limit allowable value of the processing end temperature (Th1: [° C.]) as the molten steel temperature,
An upper limit value of the pouring temperature when the processing end temperature is determined as the upper limit allowable value, which is obtained by the first prediction unit and the second prediction unit;
Considering the low temperature side maximum variation width, the pouring temperature does not fall below the lower limit, the lower limit allowable value of the treatment end temperature,
Display means for displaying, on the same screen, the lower limit value of the pouring temperature obtained by the first prediction means and the second prediction means when the processing end temperature is set as the lower limit allowable value.

  Thus, the molten steel processing operator can visually and easily determine how much the processing end temperature should be set through the screen of the display means so that the pouring temperature falls within the pouring temperature range. .

The operation device used in the steel manufacturing process is configured as follows.
Based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1 prediction means is provided.
Based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C]) and the low temperature side maximum variation width (ΔTdd (t): [° C]) of the temperature drop width can be predicted. 2nd prediction means.
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle that is already being transported,
The molten steel in the ladle is measured by the first prediction means and the second prediction means based on the treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment. The upper and lower limits of the pouring temperature as the temperature when pouring into the mold,
Is displayed on the same screen, and the content displayed on the screen is updated every appropriate time.

Thereby, when there is a change in the operation schedule after the molten steel treatment is completed, it is visually confirmed from the screen of the display means whether or not the pouring temperature is within the pouring temperature range after the change of the operation schedule. Judge quickly and easily.
Therefore, for example, when there is a possibility that the pouring temperature may exceed the upper limit value of the pouring temperature range and / or the lower limit value thereof, the molten steel processing operator as an operator of the molten steel processing equipment Can notify the continuous casting operator as the operator of the continuous casting facility in advance of the change and the required operating conditions.

The operation device used in the steel manufacturing process is configured as follows.
Based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1 prediction means is provided.
Based on the operating conditions of the steel manufacturing process, the maximum variation width (ΔTdu (t): [° C.]) and the maximum variation width (ΔTdd (t): [° C.]) of the temperature drop are predicted. Possible second prediction means.
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle still in the process of molten steel,
Even if the high temperature side maximum variation width is taken into account, the molten steel does not exceed the upper limit as the temperature when pouring into the mold, the molten steel in the ladle at the end of the molten steel treatment The upper limit allowable value of the processing end temperature (Th1: [° C.]) as the molten steel temperature,
An upper limit value of the pouring temperature when the processing end temperature is determined as the upper limit allowable value, which is obtained by the first prediction unit and the second prediction unit;
Considering the low temperature side maximum variation width, the pouring temperature does not fall below the lower limit, the lower limit allowable value of the treatment end temperature,
The lower limit value of the pouring temperature when the processing end temperature is determined as the lower limit allowable value, which is obtained by the first prediction unit and the second prediction unit,
Prior to the ladle, the molten steel is processed, and regarding the ladle already being transported,
Based on the measured processing end temperature (Th1: [° C.]), the pouring temperature of the molten steel as the temperature at which the molten steel is poured into the mold is obtained by the first predicting means and the second predicting means. Upper and lower limits;
Is displayed on the same screen, and the content displayed on the screen is updated every appropriate time.

  Thereby, the operating conditions of the molten steel processing equipment and the operating conditions of the continuous casting equipment can be comprehensively and comprehensively studied.

  It is preferable that the display means also displays a measured value of the pouring temperature on the screen.

  According to this, it is possible to easily determine the validity of the prediction results obtained by the first prediction unit and the second prediction unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the present embodiment, the molten steel processing facility is provided with an operation management device as an operation device used in the steel manufacturing process, and the operation management device predicts the temperature of steel output from the ladle. Equipped with a machine.

  The operation management device includes an arithmetic processing unit (so-called CPU, etc.) and a storage unit (so-called ROM, RAM, etc.), a display as a display means capable of displaying numerical values, graphs, etc. A keyboard as input means that can be input to the arithmetic processing section or the storage section, and a telephone as contact means with a continuous casting operator are provided.

  The temperature predictor also includes an arithmetic processing unit and a storage unit, and is electrically connected to the operation management device. Thereby, the said temperature prediction machine is comprised so that a two-way data communication with the said operation management apparatus is possible.

  In the temperature predictor (first predictor), the operation management device is configured to start pouring the molten steel in the ladle from the end of the molten steel treatment to the mold based on the operating conditions of the steel manufacturing process. Temperature drop width (ΔTd (t), also referred to as predicted temperature drop width: [° C.]) is predictable.

In addition, the operation management apparatus is also configured so that, in the temperature predictor (second predictor), the maximum temperature variation width (ΔTdu (t): [° C.]) and the low temperature side maximum variation width (ΔTdd (t): [° C.]) are predictable.
In the present embodiment, the first prediction unit and the second prediction unit are both the temperature predictors.

Note that “Δ” in the high temperature side maximum variation width ΔTdu (t) and the low temperature side maximum variation width ΔTdd (t) is a symbol meaning “width”. Further, “t” represents time, and the possible range is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.
A specific prediction method such as the temperature drop width ΔTd (t) will be described later.

  Next, the contents displayed on the display in this embodiment will be described with reference to FIG.

As shown in the figure, a coordinate axis 1 is displayed on the display, with the horizontal axis representing time and the vertical axis representing molten steel temperature.
On the coordinate axis 1, an upper limit value Tcmax and a lower limit value Tcmin of the pouring temperature range that are previously input / stored in the storage unit of the operation management apparatus via the keyboard or the like are displayed simultaneously.

  Further, as shown in the figure, the following data and the like are displayed on the coordinate axis 1 as points, straight lines, curves, and the like.

  For example, regarding the ladle A (charge A) that is still in the process of molten steel, even if the high temperature side maximum variation width ΔTdu (t) is added, the pouring temperature does not exceed the upper limit value Tcmax. The allowable value is displayed as a point (reference numeral a1 in the figure).

The upper limit allowable value a1 is a value obtained by the following formula.
a1 = MIN (Tcmax + ΔTd (t) −ΔTdu (t))
However, MIN (x) represents the minimum value of x.

The upper limit allowable value a1 displayed at this point is preferably displayed at the same time as the scheduled end time of the molten steel treatment. Because, as described above, the upper limit allowable value a1 is the upper limit allowable value of the processing end temperature Th1, and the processing end temperature Th1 means the molten steel temperature at the end of the molten steel processing of the molten steel in the ladle A. Because it does.
The upper limit allowable value a1 may be displayed as a numerical value at an arbitrary place in the display screen instead of being displayed as a point.

  Further, the upper limit value of the pouring temperature obtained by the first predicting means and the second predicting means when the processing end temperature Th1 is set to the upper limit allowable value a1 is displayed as a curve (reference numeral a2 in the figure). The

The upper limit value a2 is obtained by the following equation that is a function of time (t).
a2 (t) = Th1−ΔTd (t) + ΔTdu (t)

  Further, even if the low temperature side maximum variation width ΔTdd (t) is taken into account, the lower limit allowable value of the processing end temperature Th1 at which the pouring temperature does not fall below the lower limit value Tcmin is indicated by a point (reference numeral a3 in the figure).

The lower limit allowable value a3 is a value obtained by the following formula.
a3 = MAX (Tcmin + ΔTd1 (t) + ΔTdd (t))
However, MAX (x) represents the maximum value of x.

The lower limit allowable value a3 displayed at this point is also preferably displayed at the same time as the scheduled end time of the molten steel treatment. The reason is as described above.
The lower limit allowable value a3 may also be displayed as a numerical value at an arbitrary place in the display screen instead of being displayed as a point.

  Moreover, the lower limit value of the pouring temperature obtained by the first predicting means and the second predicting means when the processing end temperature Th1 is the lower limit allowable value a3 is displayed as a curve (reference numeral a4 in the figure). The

The lower limit value a4 is also obtained by the following equation that is a function of time (t).
a4 (t) = Th1−ΔTd (t) −ΔTdd (t)

  In addition, the upper limit and the lower limit of the temperature of the molten steel discharged from the ladle are also displayed on the screen (reference numerals a5 and a6 in the figure).

  The above is the content displayed as information about the ladle A (charge A) that is still being processed.

The molten steel processing operator who is operating the operation management device is configured such that the temperature of the molten steel processed in the ladle A is not less than the lower limit allowable value a3 and the upper limit allowable value a1 or less at the end of the molten steel processing. Thus, the temperature of the molten steel is adjusted by the above-described method (Al temperature rise or scrap cooling).
In other words, the temperature drop width ΔTd (t), the high temperature side maximum variation width ΔTdu and the low temperature side maximum variation width ΔTdd of the temperature drop width ΔTd (t) are predicted, and the processing end temperature Th1 is expressed by the following equation: The molten steel processing equipment is operated so as to satisfy (1) and (2) at the same time.
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)

  On the other hand, with respect to the ladle B / C (charge B / C) that has been molten steel processed prior to the ladle A and is already being transported, the measured end temperature Th1 of the molten steel in the ladle B / C is It is displayed as a point (reference numerals b1 and c1 in the figure).

  The processing end temperature Th1 may be displayed as a numerical value at an arbitrary place in the screen of the display instead of being displayed as a point, and an embodiment in which the processing end temperature Th1 is not even displayed is conceivable.

  Further, based on the processing end temperature Th1, the upper limit value and the lower limit value of the pouring temperature obtained by the first prediction means and the second prediction means are curves (reference numerals b2, c2, b4, c4 in the figure). Is displayed.

In addition, the said upper limit b2 * c2 and lower limit b4 * c4 are calculated | required by the following formula which is a function of time (t).
b2 (t) (or c2 (t)) = Th1−ΔTd (t) + ΔTdu (t)
b4 (t) (or c4 (t)) = Th1−ΔTd (t) −ΔTdd (t)
The upper limit values b2 and c2 and the lower limit values b4 and c4 obtained by the above two formulas change as the operating conditions change, and should be updated every appropriate time (for example, every 1 to 5 minutes). Is preferred. It is also desirable to issue a command to the system and update it immediately when the computer managing the operation recognizes the change in state or when the computer changes the operation command. “Updating” means causing the first prediction unit and the second prediction unit to recalculate at least the upper limit value b2 · c2 and the lower limit value b4 · c4 of the pouring temperature, and calculate the display content of the display concerned. To reflect the results.
Of course, not only the upper limit values b2 and c2 and the lower limit values b4 and c4, but all the contents displayed on the screen such as the upper limit allowable value a1 are updated at appropriate intervals. Also good.

  The above is data or the like displayed on the coordinate axis 1 by points, straight lines, curves, etc. In the present embodiment, the following other data is displayed by points, straight lines, curves, etc.

That is, the actually measured value of the pouring temperature is displayed as a point (symbol c5 in the figure).
Of course, the measured value c5 of the pouring temperature displayed at the point is preferably displayed at the same time as the actual measurement time.

  As described above, in the present embodiment, the steel manufacturing process is operated by the following method.

Predict the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold.
In addition, the maximum high temperature side variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width are predicted.
And the molten steel processing equipment is operated so that the treatment end temperature (Th1: [° C]) of the molten steel in the ladle as the molten steel temperature at the end of the molten steel processing satisfies the following formulas (1) and (2) at the same time. To do.
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)

  This ensures that the pouring temperature is within the pouring temperature range.

  Further, as described above, the operation management device (operation device) used in the steel manufacturing process in the present embodiment is configured as follows.

That is, based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1st prediction means (the arithmetic processing part of the said temperature predictor) is provided. The arithmetic processing unit of the temperature predictor, based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C.)) and the low temperature side maximum variation width (ΔTdd ( t): [° C.] is also a second predicting means capable of predicting.
In addition, a display is provided as appropriate display means.
On the screen of the display, an upper limit value Tcmax and a lower limit value Tcmin of the pouring temperature range are displayed.
Moreover, the following content is displayed on the said screen regarding the ladle A still in the process of molten steel.
That is, the upper limit allowable value a1 of the processing end temperature Th1 is displayed in which the pouring temperature does not exceed the upper limit value Tcmax even if the high temperature side maximum variation width ΔTdu (t) is taken into account.
In addition, the upper limit value a2 of the pouring temperature when the processing end temperature Th1 is set to the upper limit allowable value a1 obtained by the first prediction unit and the second prediction unit is displayed.
Further, the lower limit allowable value a3 of the processing end temperature Th1 is displayed in which the pouring temperature does not fall below the lower limit value Tcmin even if the low temperature side maximum variation width ΔTdd (t) is taken into account.
Further, the lower limit value a4 of the pouring temperature when the processing end temperature Th1 is set to the lower limit allowable value a3, which is obtained by the first prediction unit and the second prediction unit, is displayed.

  Thus, the molten steel processing operator can visually and easily determine how much the processing end temperature should be set through the screen of the display means so that the pouring temperature falls within the pouring temperature range. .

  Further, as described above, the operation management device (operation device) used in the steel manufacturing process in the present embodiment may be configured as follows.

That is, based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1st prediction means (the arithmetic processing part of the said temperature predictor) is provided. The arithmetic processing unit of the temperature predictor, based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C.)) and the low temperature side maximum variation width (ΔTdd ( t): [° C.] is also a second predicting means capable of predicting.
In addition, a display is provided as appropriate display means.
An upper limit value Tcmax and a lower limit value Tcmin of the pouring temperature range are displayed on the screen of the display.
Moreover, the following content is displayed on the said screen regarding the ladle B * C which has been molten steel processed prior to the ladle A and is already being conveyed.
An upper limit value b2 · c2 and a lower limit value b4 · c4 of the pouring temperature calculated by the first prediction means and the second prediction means based on the measured processing end temperature Th1 are displayed.
The content displayed on the screen (at least the upper limit value b2 · c2 and / or the lower limit value b4 · c4) is updated every appropriate time.

Thereby, when there is a change in the operation schedule after the molten steel treatment is completed, it is visually confirmed from the screen of the display means whether or not the pouring temperature is within the pouring temperature range after the change of the operation schedule. Judge quickly and easily.
Therefore, for example, when there is a possibility that the pouring temperature may exceed the upper limit value Tcmax of the pouring temperature range and / or the lower limit value thereof, the molten steel processing operator may be the continuous casting operator. On the other hand, the fact and the change of the required operating conditions can be notified in advance.

  Further, as described above, the operation management device (operation device) used in the steel manufacturing process in the present embodiment is configured as follows.

That is, based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1st prediction means (the arithmetic processing part of the said temperature predictor) is provided. The arithmetic processing unit of the temperature predictor, based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C.)) and the low temperature side maximum variation width (ΔTdd ( t): [° C.] is also a second predicting means capable of predicting.
In addition, a display is provided as appropriate display means.
On the screen of the display, an upper limit value Tcmax and a lower limit value Tcmin of the pouring temperature range are displayed.
Moreover, the following content is displayed on the said screen regarding the ladle A still in the process of molten steel.
That is, the upper limit allowable value a1 of the processing end temperature Th1 is displayed in which the pouring temperature does not exceed the upper limit value Tcmax even if the high temperature side maximum variation width ΔTdu (t) is taken into account.
In addition, the upper limit value a2 of the pouring temperature when the processing end temperature Th1 is set to the upper limit allowable value a1 obtained by the first prediction unit and the second prediction unit is displayed.
Further, the lower limit allowable value a3 of the processing end temperature Th1 is displayed in which the pouring temperature does not fall below the lower limit value Tcmin even if the low temperature side maximum variation width ΔTdd (t) is taken into account.
Further, the lower limit value a4 of the pouring temperature when the processing end temperature Th1 is set to the lower limit allowable value a3, which is obtained by the first prediction unit and the second prediction unit, is displayed.
Moreover, the following content is displayed on the said screen regarding the ladle B * C which has been molten steel processed prior to the ladle A and is already being conveyed.
An upper limit value b2 · c2 and a lower limit value b4 · c4 of the pouring temperature calculated by the first prediction means and the second prediction means based on the measured processing end temperature Th1 are displayed.
The content displayed on the screen (at least the upper limit value b2 · c2 and / or the lower limit value b4 · c4) is updated every appropriate time.

  Thereby, the operating conditions of the molten steel processing equipment and the operating conditions of the continuous casting equipment can be comprehensively and comprehensively studied.

  It is preferable that the measured value of the pouring temperature is also displayed on the screen of the display as the display means. According to this, it is possible to easily determine the validity of the prediction results obtained by the first prediction unit and the second prediction unit.

  Next, an operation method of the steel manufacturing process in the case where there is no processing end temperature Th1 that simultaneously satisfies the above formulas (1) and (2) will be described (Aspect D of the present invention). Specifically, this is a case where the right side of the equation (2) exceeds the right side of the equation (1).

In this embodiment, in the above case, the molten steel processing facility is operated so that the processing end temperature Th1 satisfies the following formula (3).
Th1 = Tcmin + ΔTd (t) + ΔTdd (t) (3)
In short, it is a compromise that the pouring temperature exceeds the upper limit value Tcmax of the pouring temperature range, while it is reliably prevented from falling below the lower limit value Tcmin.
If operated in this way, the pouring temperature is set to the lower limit value Tcmin of the pouring temperature range while suppressing the maximum temperature range where the pouring temperature may exceed the upper limit value Tcmax of the pouring temperature range as much as possible. It is possible to reliably avoid falling below.
Therefore, continuous casting can be continued without problems.

Further, when there is no processing end temperature Th1 that simultaneously satisfies the above formulas (1) and (2), and the tundish is provided with an appropriate molten steel heating means, the processing end temperature Th1 is as follows: It is also conceivable to operate the molten steel processing equipment so as to satisfy the formula (4).
Th1 = Tcmax + ΔTd (t) −ΔTdu (t) (4)
In short, it is possible to reliably prevent the pouring temperature from exceeding the upper limit value Tcmax of the pouring temperature range, while making a compromise below the lower limit value Tcmin.
If operated in this way, it can be reliably avoided that the pouring temperature exceeds the upper limit value Tcmax of the pouring temperature range, while the pouring temperature does not fall below the lower limit value Tcmin of the pouring temperature range. The point can be compensated by the molten steel heating means.
Specifically, when the pouring temperature is likely to fall below the lower limit value Tcmin, the molten steel in the tundish is heated using the molten steel heating means.
Therefore, continuous casting can be continued without problems.

Further, when there is no processing end temperature Th1 that satisfies the above formulas (1) and (2) at the same time, it is considered to operate the molten steel processing equipment so that the processing end temperature Th1 satisfies the following formula (5). It is done.
MAX (Th1−ΔTd (t) + ΔTdu (t) −Tcmax) −
MAX (Tcmin− (Th1−ΔTd (t) −ΔTdd (t))) = 0 (5)
In short, the molten steel processing equipment is operated so that the maximum temperature range in which the pouring temperature may exceed the upper limit value of the pouring temperature range and the maximum temperature range in which the pouring temperature may also fall below the lower limit value are substantially the same. To do.
Thereby, the probability that the pouring temperature is within the pouring temperature range can be improved as much as possible.

As mentioned above, although the preferable three operation methods in the case where processing end temperature Th1 which satisfies the said Formula (1) and (2) does not exist simultaneously were demonstrated, it is preferable that the manufacturing process of steel is operated with the following method. .
That is, when operated by the above three methods (see the above formulas (3) to (5)), the molten steel processing operator tells the continuous casting operator the processing end temperature Th1 and the pouring temperature. The maximum temperature range that may exceed the upper limit value Tcmax of the range and / or the maximum temperature range that may fall below the lower limit value Tcmin may be notified in advance.
As described above, “in advance” of “notify in advance” specifically means “before molten steel of the corresponding charge is poured into the mold”.
According to this, since the continuous casting operator can grasp in advance each information related to the temperature of the molten steel, the continuous casting operator needs to change the casting conditions or move the pouring start time back and forth. Can be dealt with without any problems.
The “pouring start time” is the time at which molten steel is first poured into a mold (or tundish) when starting continuous casting.
In the present embodiment, the molten steel processing operator is supposed to communicate with the continuous casting operator through, for example, a telephone included in the operation management device, but the communication means is not limited to this.

Moreover, when the operation is performed so that the pouring temperature never falls below the lower limit value Tcmin of the pouring temperature range (see the above formula (3)), the steel manufacturing process is operated by the following method. Good.
That is, the molten steel processing operator may instruct the continuous casting operator in advance at least one of the continuous casting speed and the pouring start time.
In short, it does not simply notify numerical data such as the processing end temperature Th1, but instructs a specific method of operating the continuous casting machine.
As described above, due to operational circumstances, it is difficult for the continuous casting operator to change the continuous casting speed and the pouring start time in a short time unless there is an instruction in advance.
Therefore, as described above, the molten steel processing operator gives an appropriate continuous casting speed or pouring start time to the continuous casting operator in advance, and the continuous casting operator changes them with a margin. It can be done.

Further, when the operation is performed so that at least the pouring temperature does not exceed the upper limit value Tcmax of the pouring temperature range (see the above formula (4)), the steel manufacturing process may be operated by the following method. .
That is, the molten steel processing operator may instruct the continuous casting operator in advance at least one of the continuous casting speed, the pouring start time, and the heating condition of the molten steel heating means of the tundish. .
In short, it does not simply notify numerical data such as the processing end temperature Th1, but instructs a specific method of operating the continuous casting machine.
As described above, it is difficult for the continuous casting operator to change the continuous casting speed, the pouring start time, and the heating condition of the molten steel heating means in a short time unless otherwise instructed in advance.
Therefore, as described above, the molten steel processing operator instructs the continuous casting operator in advance to an appropriate continuous casting speed or a pouring start time, and heating conditions of the molten steel heating means, thereby the continuous casting operator. These can be changed with ease.
The molten steel heating means is, for example, a plasma heating apparatus or an induction heating apparatus, and the heating condition is, for example, an applied voltage set in the heating apparatus.

Next, the processing end temperature Th1 is measured, the temperature drop width ΔTd (t) is predicted, and the high temperature side maximum variation width ΔTdu (t) and the low temperature side maximum variation width ΔTdd (t) of the temperature drop width are predicted. Then, a case where at least one of the following formulas (6) and (7) is not satisfied will be described (reference signs X and Y in FIG. 3).
Th1−ΔTd (t) + ΔTdu (t) ≦ Tcmax (6)
Th1-ΔTd (t) −ΔTdu (t) ≧ Tcmin (7)

  In this embodiment, in the above case, the molten steel processing operator instructs the continuous casting facility in advance on the operating conditions of the continuous casting equipment.

That is, it is difficult for the continuous casting operator to change the operating conditions of the continuous casting equipment in a short time unless there is an instruction in advance due to operational circumstances.
Therefore, as described above, the molten steel processing operator instructs the continuous casting operator in advance with appropriate operating conditions of the continuous casting equipment, and the continuous casting operator changes this with sufficient margin. be able to.

  Further, in this embodiment, the operating conditions of the continuous casting equipment that the molten steel processing operator instructs in advance to the continuous casting operator are the continuous casting speed and the casting of molten steel first when starting continuous casting. It is preferable to set at least one of the pouring start time as the time at which pouring starts.

That is, it is difficult for the continuous casting operator to change the continuous casting speed and the pouring start time in a short time unless there is an instruction in advance due to operational circumstances.
Therefore, as described above, the molten steel processing operator gives an appropriate continuous casting speed and pouring start time to the continuous casting operator in advance, and the continuous casting operator changes them with a margin. can do.

  Further, when the formula (7) is not satisfied and the molten steel in the ladle is poured into a mold through a tundish provided with appropriate molten steel heating means, the molten steel processing operator The operating condition of the continuous casting equipment instructed in advance to the continuous casting operator is at least one of a continuous casting speed, a pouring start time, and a heating condition for the molten steel of the molten steel heating means. It is preferable.

That is, due to operational circumstances, unless otherwise instructed in advance, it is difficult for the continuous casting operator to change the continuous casting speed, the pouring start time, and the heating conditions for the molten steel of the molten steel heating means in a short time.
Thus, as described above, the molten steel processing operator instructs the continuous casting operator in advance an appropriate continuous casting speed, a pouring start time, and a heating condition for the molten steel of the molten steel heating means, so that the continuous casting is performed. Operators can change these with ease.

Next, a specific prediction method for the temperature drop width ΔTd (t), the high temperature side maximum variation width ΔTdu (t), and the low temperature side maximum variation width ΔTdd (t) will be described.
Here, first, the case where “the molten steel in the ladle is poured directly into the mold provided in the continuous casting machine” will be described. Next, “the molten steel in the ladle is The case where the molten metal is poured into the mold provided in the continuous casting machine through the tundish will be described.

◆ “When molten steel in the ladle is poured directly into the mold of the continuous caster”
In the present embodiment, the temperature predictor as the first predicting unit and the second predicting unit includes the temperature drop width ΔTd (t), the high temperature side maximum variation width ΔTdu (t), and the low temperature side maximum variation width ΔTdd ( t) is configured to be predictable.

More specifically, the temperature predictor is configured to be able to predict the standard value, the upper limit value, and the lower limit value of the time change in the temperature of the steel discharged from the ladle.
Here, the “standard value of the time change of the steel output temperature” is obtained by subtracting the temperature drop width ΔTd (t) from the processing end temperature Th1 as shown in the following equation.
(Standard value of time change of steel output temperature) = Th1−ΔTd (t)
Further, the “upper limit value of time variation of the steel output temperature” is obtained by adding the maximum variation width ΔTdu (t) on the high temperature side to the “standard value of time change of the steel output temperature” as shown in the following equation. .
(Upper limit of time change of steel temperature) = Th1−ΔTd (t) + ΔTdu (t)
Further, the “lower limit value of the time change of the steel output temperature” is obtained by subtracting the low temperature side maximum variation width ΔTdd (t) from the “standard value of the time change of the steel output temperature” as shown in the following formula.
(Lower limit of time change of steel output temperature) = Th1−ΔTd (t) −ΔTdd (t)
The temperature predictor predicts the standard value, upper limit value, and lower limit value of the time change in the temperature of the steel discharged from the ladle, thereby allowing the temperature drop width ΔTd (t) and its high temperature side maximum variation width. ΔTdu (t) and the low temperature side maximum variation width ΔTdd (t) can be predicted together.

  For the above reasons, for convenience of explanation, a specific prediction method for the temperature drop width ΔTd (t), the high temperature side maximum variation width ΔTdu (t), and the low temperature side maximum variation width ΔTdd (t) will be described. Instead, a specific method for predicting the standard value, the upper limit value, and the lower limit value of the time change in the temperature of steel output from the ladle will be described.

The operation management device described above is electrically connected to various control devices and sensor devices provided in a molten steel processing device, a ladle conveying device, and the like of a molten steel processing facility. As a result, the molten steel processing apparatus, ladle conveying apparatus, and the like are configured such that the operation / state is always grasped by the operation management apparatus, and appropriately according to instructions from the operation management apparatus. It is configured to be driven.
And thereby, the said operation management apparatus is comprised so that the molten steel temperature in the ladle at the time of completion | finish of a molten steel process can be measured / grasped | ascertained via the thermocouple (sensor apparatus) etc. with which the said molten steel processing apparatus is equipped, for example. ing. In addition, it is supposed that the said molten steel temperature is substantially uniform in the ladle at the time of completion | finish of a molten steel process. Similarly, the said operation management apparatus is comprised so that the slag temperature in a ladle can also be measured / understood.

  The temperature predictor is the appropriate operation data received from the operation management device or the initial refractory temperature as the temperature of the ladle refractory at the end of the molten steel processing, and the end of steelmaking from the end of the molten steel processing The calculation processing unit (the first prediction unit and the second prediction unit) is configured to be able to execute an unsteady heat transfer calculation program capable of predicting a temporal change in the steel output temperature up to the time point.

  The program is stored in advance in a storage unit of the temperature predictor, for example, and the arithmetic processing unit is configured to be able to read the program from the storage unit as needed when attempting to execute the program. . Instead, the program is stored in another readable / writable recording medium, and the arithmetic processing unit is configured to be able to read the program from the recording medium at any time when the program is to be executed. May be.

The operation data is, for example, the molten steel temperature and the slag temperature in the ladle at the end of the molten steel treatment, the operational schedule of the molten steel treatment and the casting treatment, and various operational parameters to be described later (Table 1).
In addition, the operation schedule of molten steel processing or casting processing specifically includes the end time of the molten steel processing, the start time of steel output to the continuous casting machine provided in the continuous casting equipment, and the end time of steel output.

  The initial refractory temperature includes the current operation (the various operation parameters) received from the operation management device and the past operation (Table 1 described later) stored in the storage unit of the temperature predictor. And Table 2).

  Further, in the present embodiment, the initial refractory temperature includes the standard value of the initial refractory temperature obtained based on the current and past operations (operation conditions of the steel manufacturing process), and the current and past operations. The upper limit value of the initial refractory temperature obtained based on the above and the lower limit value of the initial refractory temperature obtained based on the current and past operations are included.

  The temperature predictor is configured to perform the unsteady heat transfer calculation in each of the three initial refractory temperatures (standard value, upper limit value, and lower limit value).

  Hereinafter, the outline of the unsteady heat transfer calculation and the calculation method of the initial refractory temperature will be described. FIG. 4 is a schematic diagram of a longitudinal sectional view of the ladle.

≪Outline of unsteady heat transfer calculation≫
In the present embodiment, the unsteady heat transfer calculation is executed by dividing the refractory of the ladle (including the ladle lid) into elements (or blocks) as follows, as shown in FIG.
The lid of the ladle is divided into four elements along the vertical direction.
The side wall of the ladle is divided into seven elements along the radial direction and divided into three blocks along the vertical direction.
The bottom plate of the ladle is divided into eight elements along the vertical direction.
The standard value, the upper limit value, and the lower limit value of the initial refractory temperature described above are individually calculated and set for each of the above elements (see FIG. 8 described later).
Note that the initial refractory temperature of the ladle is likely to be affected by the current operation (various operation parameters: see Table 1 below) (see FIGS. 6 and 7 below).
Therefore, in this embodiment, the initial refractory temperature of the ladle side wall and bottom plate is appropriately determined based on the current reference and the past operation of an appropriate reference initial refractory temperature (see Table 2; see FIG. 5 below). (Simply speaking, FIG. 8 = FIG. 5 + FIG. 6 + FIG. 7).

In Table 1, when there is an obvious abnormality in various operation parameters received from the operation management device, an operation parameter correction table used for correcting the operation parameters as appropriate, and corrections are made as necessary. A temperature correction coefficient calculation table for obtaining a temperature correction coefficient for correcting the reference initial refractory temperature based on the current operation (various operation parameters) is shown. The table 1 is input / stored in advance in the storage unit of the temperature predictor.
Table 2 shows the reference initial refractory temperature table prepared in advance for each processing method of the molten steel processing and for each element of the ladle lid, the side wall, and the bottom plate. Table 2 is also input / stored in advance in the storage unit of the temperature predictor. In addition, the said reference | standard initial refractory temperature regarding the side wall of a ladle is as shown, for example in FIG.

  FIG. 9 is a diagram showing a subroutine for calculating the initial refractory temperature of the ladle. In the present embodiment, the subroutine of this figure is executed not only after the molten steel processing is completed but also at any time during the molten steel processing in the arithmetic processing unit of the temperature predictor (S301). When the arithmetic processing unit executes the subroutine, the temperature predictor receives the operation data from the operation management device as appropriate, or is input / stored in advance in the storage unit of the temperature predictor. Various tables (see Tables 1 and 2) can be referred to as appropriate.

<< Constant Setting (S302) >>: See FIG. 10 First, each constant used in this subroutine is set.
・ "Atmosphere temperature" is the outside air temperature.
-"Internal virtual thickness" is defined by the following formula.
(Internal virtual thickness) = (Thermal conductivity of the refractory) / (Thermal conductivity of the deposit) × (The thickness of the deposit)
That is, since there are deposits such as residual slag, metal, and altered refractory between the inside of the refractory and the molten steel, heat conduction is reduced. Thus, the virtual inner thickness is intended to be taken into account by replacing the influence of the deposits such as residual slag with the increase in the thickness of the refractory toward the inner surface.
-"Outer surface virtual thickness" is defined by the following formula.
(Outside virtual thickness) = (Thermal conductivity of refractory) / (Thermal conductivity of iron skin, etc.) x (Thickness of iron skin, etc.)
That is, heat conduction is reduced because there are iron skin and various deposits between the outside of the refractory and the atmosphere. Therefore, the virtual outer surface thickness is intended to be taken into account by replacing the influence of these iron shells and the like as an increase in the thickness of the refractory toward the outer surface.

<< Reading Initial Refractory Temperature (Lid) (S303) >>: Refer to FIG. 11 In this embodiment, the initial refractory temperature of each element of the ladle lid is prepared in advance as shown in Table 2 above. The refractory temperature is read and used as it is. In addition, the standard value, the upper limit value, and the lower limit value of the initial refractory temperature of the ladle lid are set to the same value as long as the calculation is started.

<< Acquisition of Various Operation Parameters (S304) >>: See FIG. 12 Next, the current operation (various operation parameters) is acquired / received from the operation management apparatus.
Note that the operation parameters that cannot be directly acquired from the operation management device are appropriately calculated in the temperature predictor based on the operation parameters that can be acquired. For example, this parameter (7) “time from the end of heat retention in the ladle to the end of steel output from the converter” indicates the heat retention end time and the converter steel output end time from the operation management device. It can be calculated by obtaining and determining the difference between them.

<< Correction of Operation Parameter and Calculation of Temperature Correction Coefficient (S305) >>: See FIG. 13 Next, it is verified whether or not the current operation parameter obtained in (S304) is abnormal.
Specifically, for example, if the parameter (1) cannot be obtained / received from the operation management device for some reason, it will cause a problem in calculation as it is, so the default of the operation parameter correction table shown in Table 1 The value will be used instead.
For example, when the parameter (2) acquired / received from the operation management device is an abnormally large value for some reason, the upper limit value of the operation parameter correction table is used instead.
Then, the temperature correction coefficient (standard value and upper limit value, lower limit value) is changed to a current operation (operation parameter) (corrected as necessary) and a past operation (each of the temperature correction coefficient calculation table). Coefficient).

<< Calculation of Initial Refractory Temperature (Side Wall) (S306) >>: See FIG. 14 Next, the initial refractory temperature (standard value, upper limit value, and lower limit value) of the side wall of the ladle is calculated.
As described above, the side wall of the ladle is divided into a plurality of elements along the radial direction and the vertical direction. Since the temperature of the molten steel in the ladle is made uniform at the end of the molten steel treatment, the initial refractory temperature has a temperature difference only in the radial direction at the end of the molten steel treatment, and the temperature difference in the vertical direction. Do not have.
Therefore, first, the initial refractory temperature is obtained only for the element group at the lowest vertical direction on the side wall of the ladle, and the other element groups above the element group in the vertical direction are the initial refractory temperature of the element group. The same value shall be substituted.

Specifically, it is as follows.
First, as shown in the figure, an inner surface correction reference temperature is defined based on the ambient temperature and the value of the inner surface of the side wall reference temperature. The outer surface correction reference temperature is defined similarly. These inner surface correction reference temperatures and the like are used for convenience in calculation. The “side wall reference temperature inner surface value (table value)” is the temperature of the element in contact with the molten steel of the sidewall refractory, and indicates the refractory temperature of element number 1 in Table 2.

Next, the initial refractory temperature in each element of the element group is determined. The “side wall refractory coordinates (table value) (I)” is the coordinate (representative value) of the I-th element counted from the ladle inner surface in the element group, and the “representative value” It means the average value of the outer diameter and inner diameter of the element. The “side wall refractory coordinates (table value) (I)” is input / stored in advance in the storage unit of the temperature predictor. Further, the correction using the “inner surface virtual thickness” for the “side wall refractory coordinates (table value) (I)” is not performed at this stage.
First, the internal heat dissipation correction value is obtained using the previously obtained temperature correction coefficient. Since the temperature correction coefficient includes the standard value, the upper limit value, and the lower limit value as described above, the standard, upper limit, and lower limit are similarly obtained for the inner surface heat radiation correction value (see FIG. 6).
Similarly, an external heat radiation correction value is also obtained (see FIG. 7).
Then, by adding the reference initial refractory temperature (FIG. 5), the inner surface heat radiation correction value (FIG. 6) and the outer surface heat radiation correction value (FIG. 7), the initial refractory temperature on the side wall of the ladle (see FIG. 8). )
Further, the initial refractory temperature obtained as described above is substituted into the initial refractory temperature of the other element group above in the vertical direction.

<< Calculation of Initial Refractory Temperature (Bottom) (S307) >>: See FIG. 15 The calculation method of the initial refractory temperature of the bottom plate of the ladle is substantially the same as the calculation method of the initial refractory temperature of the side wall described above.

  The above is the calculation method of the standard value, the upper limit value, and the lower limit value of the initial refractory temperature in each element of the ladle refractory (see FIG. 8: S308).

The operation parameter correction table and the temperature correction coefficient calculation table shown in Table 1 and the reference initial refractory temperature table shown in Table 2 can be obtained by various methods.
For example, the past operation of molten steel processing is obtained by statistical processing, or it is obtained based on the experience of the operator of the molten steel treatment facility, or is obtained by performing a known heat transfer calculation, or a combination thereof. You can also ask.

Next, a characteristic part of the unsteady heat transfer calculation performed based on the initial refractory temperature (standard value, upper limit value, and lower limit value) obtained as described above will be described. In the present embodiment, the unsteady heat transfer calculation is executed in each case when the standard value is used as the initial refractory temperature, when the upper limit value is used, and when the lower limit value is used.
Note that the temperature predictor, when executing the unsteady heat transfer calculation, from the operation management device in advance, the molten steel temperature and slag temperature in the ladle at the end of the molten steel processing, the molten steel processing and the casting processing operation Get / receive schedules. This is because the unsteady heat transfer calculation is executed not only based on the initial refractory temperature but also based on the molten steel temperature, slag temperature, and operation schedule.

≪Outline≫
In the present embodiment, as shown in FIG. 16, a steel outlet hole through which molten steel is discharged from the ladle is provided at a predetermined distance from the center of the bottom plate of the ladle toward the side wall.
And as shown in FIG. 4, the molten steel and slag in a ladle are divided | segmented into the block of a suitable magnitude | size, and are handled. In the present embodiment, the unsteady heat transfer calculation is unsteady one-dimensional differential heat transfer calculation between the blocks when viewed microscopically. It is assumed that heat transfer between the blocks occurs with thermal convection and / or molten steel flow described later.
Note that the unsteady heat transfer calculation in the present embodiment is executed on the assumption that the amount of heat removed by the ladle (side wall / bottom plate) of the molten steel in the ladle is constant. The same applies to the shape of the ladle (side wall / bottom plate).

<< Block division of molten steel and slag >>
In the present embodiment, the molten steel is divided into at least two or more (three in this embodiment) block groups (lower block, central block, and upper block) in the vertical direction as shown in FIG. And the lower block as a block located in the vertically lowermost part among the said block group is further divided | segmented into the lower hole block by the side of the said steel hole, and the lower residence block of the other side further in the horizontal direction.
In addition, the said lower residence block has a corresponding relationship with the location where the stagnation of the molten steel flow shown in FIG. In the present embodiment, the slag floated (provided in a floated state) on the molten steel is divided into two blocks in the vertical direction.

≪Modeling of thermal convection during transportation≫
As shown in FIG. 17, it is assumed that a predetermined amount of heat moves from the lower stay block, the lower hole block, and the central block toward the upper block during the conveyance of the ladle. Thereby, the natural heat convection of the molten steel during conveyance of the ladle can be reflected in the unsteady heat transfer calculation.

≪Modeling of molten steel flow during steel production≫
As described above, stagnation occurs in the molten steel flow in the steel output at a point far from the steel output hole (see FIG. 16). And according to the simulation as shown in FIG. 16, even if this molten steel is located at the lower part of the ladle, it becomes clear that the molten steel does not come out before the molten steel on the upper side. ing.
Therefore, in the present embodiment, as long as the total amount of molten steel in the ladle exceeds the amount of molten steel represented by the lower block, the molten steel in the lower staying block crosses the boundary with other adjacent blocks. On the other hand, only when the total amount of molten steel in the ladle falls below the amount of molten steel represented by the lower block, the molten steel in the lower staying block is assumed to not flow. Is assumed to flow through the molten steel beyond the boundary with other adjacent blocks (see FIG. 18B). In short, the molten steel flow / heat transfer between the blocks is switched according to the total molten steel amount in the ladle.

≪Results of unsteady heat transfer calculation≫
FIG. 19 shows the time change of the steel output temperature obtained by the unsteady heat transfer calculation described above. As shown in the figure, according to the temperature predictor in the present embodiment, the standard value, the upper limit value, and the lower limit value of the time change of the steel output temperature can be obtained.
Moreover, the standard value (predicted value) of the time change of the said steel output temperature shown by FIG. 19 and the measured value are combined with FIG. According to this figure, it turns out that the above-mentioned unsteady heat transfer calculation can reproduce the time change of the said steel output temperature favorably qualitatively and quantitatively.

  In the present embodiment, as described above, based on the standard value, the upper limit value, and the lower limit value (see FIG. 19) of the time change of the steel output temperature obtained as described above, the temperature drop width ΔTd (t) and The high temperature side maximum variation width ΔTdu (t) and the low temperature side maximum variation width ΔTdd (t) are obtained.

◆ “When molten steel in the ladle is poured into the mold of the continuous caster via a tundish”
Next, when the molten steel in the ladle is poured into a mold provided in the continuous casting machine via a tundish, the temperature drop width ΔTd (t) and the high temperature side maximum variation width ΔTdu ( t), a specific prediction method of the low temperature side maximum variation width ΔTdd (t) will be described.
Also in this case, the temperature predictor is configured to be able to predict the standard value, the upper limit value, and the lower limit value of the time change of the steel output temperature from the tundish.
Here, the “standard value of the time change in the temperature of steel output from the tundish” is obtained by subtracting the temperature drop width ΔTd (t) from the processing end temperature Th1 as shown in the following equation.
(Standard value of time change of steel temperature from tundish) = Th1−ΔTd (t)
Further, the “upper limit value of time change of steel temperature from tundish” is the maximum variation width ΔTdu (t of the high temperature side to the “standard value of time change of steel temperature from tundish” as shown in the following formula. ) Is added.
(Upper limit value of time variation of steel temperature from tundish) = Th1−ΔTd (t) + ΔTdu (t)
Further, “the lower limit value of the time change in the temperature of steel output from the tundish” is the maximum variation width ΔTdd (t of the low temperature side from the “standard value of the time change in the temperature of steel output from the tundish” as shown in the following formula. ) Is subtracted.
(Lower limit of time variation of steel temperature from tundish) = Th1−ΔTd (t) −ΔTdd (t)
The temperature predictor predicts the standard value, the upper limit value, and the lower limit value of the time change in the temperature of the steel discharged from the tundish, so that the temperature drop width ΔTd (t) and its high temperature side maximum variation width are predicted. ΔTdu (t) and the low temperature side maximum variation width ΔTdd (t) can be predicted together.

For the above reasons, for convenience of explanation, a specific prediction method for the temperature drop width ΔTd (t), the high temperature side maximum variation width ΔTdu (t), and the low temperature side maximum variation width ΔTdd (t) will be described. Instead, a specific method for predicting the standard value, the upper limit value, and the lower limit value of the time change in the temperature of steel output from the tundish will be described.
In addition, the specific prediction method of the standard value, the upper limit value, and the lower limit value of the time change of the temperature of steel output from the ladle is as described above.
Moreover, the unsteady heat transfer calculation of the molten steel in the tundish is substantially the same as that of the molten steel in the ladle.
Therefore, hereinafter, the calculation method of the initial refractory temperature of the tundish will be mainly described.

  In this embodiment, the initial refractory temperature of the tundish is the same as that of the ladle described above, and the standard value of the initial refractory temperature obtained based on the current and past operations, and the current and past The upper limit value of the initial refractory temperature obtained based on the operation and the lower limit value of the initial refractory temperature obtained based on the current and past operations are included.

The temperature predictor is configured to perform the unsteady heat transfer calculation in each of the three initial refractory temperatures (standard value, upper limit value, and lower limit value).
Specifically, when the standard value is used as the initial refractory temperature of the ladle, the standard value is used as the initial refractory temperature of the tundish.
When the upper limit value is used as the initial refractory temperature of the ladle, the upper limit value is used as the initial refractory temperature of the tundish.
When the lower limit value is used as the initial refractory temperature of the ladle, the lower limit value is used as the initial refractory temperature of the tundish.

In Table 3, when there is an obvious abnormality in various operation parameters received from the operation management device, an operation parameter correction table used for correcting the operation parameters as appropriate, and corrections are made as necessary. A temperature correction coefficient calculation table for obtaining a temperature correction coefficient for correcting the reference initial refractory temperature of the tundish based on the current operation (various operation parameters) is shown. The table 3 is input / stored in advance in the storage unit of the temperature predictor.
Table 4 shows the reference initial refractory temperature table prepared in advance for each processing step and for each element of the tundish lid, side wall (molten steel surface), side wall (non-molten steel surface), and bottom plate. It is shown. Table 4 is also input / stored in advance in the storage unit of the temperature predictor.

FIG. 21 is a diagram showing a subroutine for calculating the initial refractory temperature of the tundish. In the present embodiment, the subroutine of this figure is executed not only after the molten steel processing is completed but also at any time during the molten steel processing in the arithmetic processing unit of the temperature predictor (S310). When the temperature predictor executes the subroutine, the temperature predictor appropriately receives the operation data from the operation management apparatus, or various tables (Table 3) previously input / stored in the storage unit of the temperature predictor. And Table 4) can be referred to as appropriate.
Note that the subroutine shown in this figure may be executed before or after the subroutine shown in FIG. 9 (related to the calculation of the initial refractory temperature of the ladle).

<< Constant Setting (S311) >>: See FIG. 22 First, each constant used in this subroutine is set.

≪Division of processing steps (S312) ≫
Next, the current operation (usage state of tundish and presence / absence of heating of molten steel) is acquired / received from the operation management device. The operation management device is electrically connected to a tundish provided in the continuous casting machine of the continuous casting equipment, and the operation management device is configured to acquire appropriate data from the tundish. .
The processing steps are classified as follows (see also Table 4).
The treatment process is “new heating” means that the number of repairs of the tundish is once or less and there is the heating.
The treatment process is “no new article heating” means that the number of repairs of the tundish is once or less and there is no heating.
The treatment process is “heat reuse” when the tundish is continuously reused and there is the heating, or the tundish is not continuously reused and the This is the case when there is heating.
The treatment process is “non-heated reuse” means that the tundish is continuously reused and there is no such heating, or the tundish is not continuous but is reused, and This is a case where there is no heating.
When there is the heating, true is substituted for an unillustrated variable “heating flag (default is false)”.

<< Reading of Initial Refractory Temperature (Lid) (S313) >>: See FIG. 23 In this embodiment, the initial refractory temperature of each element of the tundish lid is the reference initial value prepared in advance as shown in Table 4 above. The refractory temperature is read and used as it is. It should be noted that the standard value, the upper limit value, and the lower limit value of the initial refractory temperature of the tundish lid are all set to the same value as long as the calculation is started.

<< Acquisition of Various Operation Parameters (S314) >>: See FIG. 24 Next, the current operation (various operation parameters) is acquired / received from the operation management device.

<< Correction of Operation Parameter and Calculation of Temperature Correction Coefficient (S315) >>: See FIG. 25 Next, it is verified whether or not the current operation parameter obtained in the above (S314) is abnormal.

<< Calculation of initial refractory temperature (side wall: molten steel surface) (S316) >>: See FIG. 26 Next, the initial refractory temperature (standard value and upper limit value, lower limit value) of the side wall (molten steel surface) of the tundish is calculated. To do.
In addition, "side wall: molten steel surface" is what is in direct contact with molten steel among the side walls.

<< Calculation of initial refractory temperature (side wall: non-molten steel surface) (S317) >>: See FIG. 27 Next, initial refractory temperature (standard value and upper limit value, lower limit value) of the tundish side wall (non-molten steel surface) Calculate
In addition, "side wall: non-molten steel surface" is what is not in contact with molten steel among the side walls.

<< Calculation of Initial Refractory Temperature (Bottom) (S318) >>: See FIG. 28 Next, the initial refractory temperature (standard value, upper limit value, and lower limit value) of the bottom plate of the tundish is calculated.

  The above is the calculation method of the standard value, the upper limit value, and the lower limit value of the initial refractory temperature in each element of the tundish refractory (S319).

Note that the operation parameter correction table and the temperature correction coefficient calculation table shown in Table 3 and the reference initial refractory temperature table shown in Table 4 can be obtained by various methods.
For example, the past operation of molten steel processing is obtained by statistical processing, or it is obtained based on the experience of the operator of the molten steel treatment facility, or is obtained by performing a known heat transfer calculation, or a combination thereof. You can also ask.

The figure showing the shift | offset | difference with respect to the target value of the pouring temperature of molten steel, and its frequency. The figure showing the shift | offset | difference with respect to the target value of the pouring temperature of molten steel, and its frequency. The figure which shows the content displayed on a display. The schematic diagram of the longitudinal cross-sectional view of a ladle. The figure which shows reference | standard initial stage refractory temperature. The figure which shows an internal surface heat radiation correction value. The figure which shows an outer surface heat radiation correction value. The figure which shows initial stage refractory temperature. The figure which shows the subroutine for calculating the initial refractory temperature of a ladle. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. The figure which shows the simulation result of the molten steel flow of the molten steel in a ladle at the time of steel extraction. The figure which shows the model of the heat convection during conveyance. The figure which shows the model of the molten-steel flow in steeling out. The figure which shows the calculation result of the unsteady heat transfer calculation in this embodiment. The figure which shows the calculation result and actual value of unsteady heat-transfer calculation in this embodiment. The figure which shows the subroutine for calculating the initial refractory temperature of a tundish. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG. Specific contents of the subroutine shown in FIG.

Explanation of symbols

1 Coordinate axis A Charge a1 Upper limit value of treatment end temperature a2 Upper limit value of pouring temperature a3 Lower limit value of pouring temperature a4 Lower limit value of pouring temperature Tcmax Upper limit value of pouring temperature range Tcmin Lower limit value of pouring temperature range

Claims (14)

Predicting the temperature drop (ΔTd: [° C.]) from the end of the molten steel treatment to the start of pouring into the mold of the molten steel in the ladle,
Predicting the high temperature side maximum variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width,
Operate the molten steel treatment equipment so that the treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle simultaneously satisfies the following formulas (1) and (2). A method of operating a steel manufacturing process.
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
However,
Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold,
Tcmin [° C.] is a lower limit value of the pouring temperature range,
t represents time, and the range that can be taken is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished. Predicting the temperature drop (ΔTd: [° C.]) from the end of the molten steel treatment to the start of pouring into the mold of the molten steel in the ladle,
Predicting the high temperature side maximum variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width,
When the treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle that satisfies the following formulas (1) and (2) is not present,
A method for operating a steel manufacturing process, wherein the molten steel processing equipment is operated so that the processing end temperature satisfies the following formula (3).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
Th1 = Tcmin + ΔTd (t) + ΔTdd (t) (3)
However,
Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold,
Tcmin [° C.] is a lower limit value of the pouring temperature range,
t represents time, and the range that can be taken is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished. Predicting the temperature drop (ΔTd: [° C.]) from the end of the molten steel treatment to the start of pouring into the mold of the molten steel in the ladle,
Predicting the high temperature side maximum variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width,
When the molten steel in the ladle that satisfies the following formulas (1) and (2) is not present, there is no treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment,
When pouring the molten steel in the ladle into the mold through a tundish equipped with appropriate molten steel heating means,
A method for operating a steel manufacturing process, wherein the molten steel processing equipment is operated so that the processing end temperature satisfies the following formula (4).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
Th1 = Tcmax + ΔTd (t) −ΔTdu (t) (4)
However,
Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold,
Tcmin [° C.] is a lower limit value of the pouring temperature range,
t represents time, and the range that can be taken is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished. Predicting the temperature drop (ΔTd: [° C.]) from the end of the molten steel treatment to the start of pouring into the mold of the molten steel in the ladle,
Predicting the high temperature side maximum variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width,
When the treatment end temperature (Th1 [° C.]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle that satisfies the following formulas (1) and (2) is not present,
A method for operating a steel manufacturing process, wherein the molten steel processing facility is operated so that the processing end temperature satisfies the following formula (5).
Th1 ≦ Tcmax + ΔTd (t) −ΔTdu (t) (1)
Th1 ≧ Tcmin + ΔTd (t) + ΔTdd (t) (2)
MAX (Th1−ΔTd (t) + ΔTdu (t) −Tcmax) −
MAX (Tcmin− (Th1−ΔTd (t) −ΔTdd (t))) = 0 (5)
However,
Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold,
Tcmin [° C.] is a lower limit value of the pouring temperature range,
t represents time, and the range that can be taken is from the time when the molten steel in the ladle starts to be poured into the mold until the point when pouring is finished,
MAX (x (t)) represents the maximum value of x (t).   The molten steel processing operator as the operator of the molten steel processing equipment is the maximum that may exceed the upper limit value of the processing end temperature and the pouring temperature range for the continuous casting operator as the operator of the continuous casting equipment. The temperature range and / or the maximum temperature range that may be lower than the lower limit value are notified in advance, and the method for operating a steel manufacturing process according to any one of claims 2 to 4.   The molten steel processing operator as the operator of the molten steel processing equipment, to the continuous casting operator as the operator of the continuous casting equipment, poured the molten steel into the mold first when starting the continuous casting speed and continuous casting. 3. The method of operating a steel manufacturing process according to claim 2, wherein at least one of a pouring start time as a start time of the start is instructed in advance.   The molten steel processing operator as the operator of the molten steel processing equipment, to the continuous casting operator as the operator of the continuous casting equipment, poured the molten steel into the mold first when starting the continuous casting speed and continuous casting. 4. The steel manufacturing process according to claim 3, wherein at least one of a pouring start time as a start time and a heating condition for the molten steel by the molten steel heating means is instructed in advance. Operation method. Measure the treatment end temperature (Th1: [° C]) as the molten steel temperature at the end of the molten steel treatment of the molten steel in the ladle,
Predicting the temperature drop width (ΔTd: [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold,
Predicting the high temperature side maximum variation width (ΔTdu: [° C.]) and the low temperature side maximum variation width (ΔTdd: [° C.]) of the temperature drop width,
When at least one of the following formulas (6) or (7) is not satisfied,
A molten steel processing operator as an operator of the molten steel processing equipment instructs the operating conditions of the continuous casting equipment in advance to a continuous casting operator as an operator of the continuous casting equipment. How to operate the manufacturing process.
Th1−ΔTd (t) + ΔTdu (t) ≦ Tcmax (6)
Th1-ΔTd (t) −ΔTdu (t) ≧ Tcmin (7)
However,
Tcmax [° C.] is the upper limit value of the pouring temperature range as a suitable temperature range of molten steel when poured into the mold,
Tcmin [° C.] is a lower limit value of the pouring temperature range,
t represents time, and the range that can be taken is from the time when the molten steel in the ladle starts to be poured into the mold to the time when pouring is finished.   The operating conditions of the continuous casting equipment that the molten steel processing operator instructs to the continuous casting operator in advance are the continuous casting speed and the time when the molten steel is first poured into the mold when starting the continuous casting. The method for operating a steel manufacturing process according to claim 8, wherein at least one of the hot water pouring start time and When the formula (7) is not satisfied,
When the molten steel in the ladle is poured into a mold through a tundish equipped with appropriate molten steel heating means,
The operating conditions of the continuous casting equipment that the molten steel processing operator instructs in advance to the continuous casting operator are the continuous casting speed and the time when the molten steel is first poured into the mold when starting the continuous casting. 9. The method of operating a steel manufacturing process according to claim 8, wherein at least one of a pouring start time and a heating condition for the molten steel by the molten steel heating means is used. Based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1 prediction means,
Based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C]) and the low temperature side maximum variation width (ΔTdd (t): [° C]) of the temperature drop width can be predicted. Second predicting means,
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle still in the process of molten steel,
Even if the high temperature side maximum variation width is taken into account, the molten steel does not exceed the upper limit as the temperature when pouring into the mold, the molten steel in the ladle at the end of the molten steel treatment The upper limit allowable value of the processing end temperature (Th1: [° C.]) as the molten steel temperature,
An upper limit value of the pouring temperature when the processing end temperature is determined as the upper limit allowable value, which is obtained by the first prediction unit and the second prediction unit;
Considering the low temperature side maximum variation width, the pouring temperature does not fall below the lower limit, the lower limit allowable value of the treatment end temperature,
The lower limit value of the pouring temperature when the processing end temperature is determined as the lower limit allowable value, which is obtained by the first prediction unit and the second prediction unit,
An operation apparatus used for a steel manufacturing process, characterized by comprising display means for displaying the same on the same screen. Based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1 prediction means,
Based on the operating conditions of the steel manufacturing process, the high temperature side maximum variation width (ΔTdu (t): [° C]) and the low temperature side maximum variation width (ΔTdd (t): [° C]) of the temperature drop width can be predicted. Second predicting means,
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle that is already being transported,
The molten steel in the ladle is measured by the first prediction means and the second prediction means based on the treatment end temperature (Th1: [° C.]) as the molten steel temperature at the end of the molten steel treatment. The upper and lower limits of the pouring temperature as the temperature when pouring into the mold,
Is displayed on the same screen.
An operation apparatus used in a steel manufacturing process, characterized in that the content displayed on the screen is updated every appropriate time. Based on the operating conditions of the steel manufacturing process, the temperature drop width (ΔTd (t): [° C.]) of the molten steel in the ladle from the end of the molten steel treatment to the start of pouring into the mold can be predicted. 1 prediction means,
Based on the operating conditions of the steel manufacturing process, the maximum variation width (ΔTdu (t): [° C.]) and the maximum variation width (ΔTdd (t): [° C.]) of the temperature drop are predicted. Possible second prediction means,
The upper and lower limits of the pouring temperature range as a suitable temperature range when pouring the molten steel into the mold,
For ladle still in the process of molten steel,
Even if the high temperature side maximum variation width is taken into account, the molten steel does not exceed the upper limit as the temperature when pouring into the mold, the molten steel in the ladle at the end of the molten steel treatment The upper limit allowable value of the processing end temperature (Th1: [° C.]) as the molten steel temperature,
An upper limit value of the pouring temperature when the processing end temperature is determined as the upper limit allowable value, which is obtained by the first prediction unit and the second prediction unit;
Considering the low temperature side maximum variation width, the pouring temperature does not fall below the lower limit, the lower limit allowable value of the treatment end temperature,
The lower limit value of the pouring temperature when the processing end temperature is determined as the lower limit allowable value, which is obtained by the first prediction unit and the second prediction unit,
Prior to the ladle, the molten steel is processed, and regarding the ladle already being transported,
Based on the measured processing end temperature (Th1: [° C.]), the pouring temperature of the molten steel as the temperature at which the molten steel is poured into the mold is obtained by the first predicting means and the second predicting means. Upper and lower limits;
Is displayed on the same screen.
An operation apparatus used in a steel manufacturing process, characterized in that the content displayed on the screen is updated every appropriate time. The display unit according to claim 12 or 13,
A measured value of the pouring temperature is also displayed on the screen, and the operating device used in the steel manufacturing process.

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