KR101325181B1 - Method and apparatus for controlling thickness of molten mold flux - Google Patents

Abstract

According to the present invention, a molten mold flux injection step of calculating an injection amount of molten mold flux according to a casting width and injecting the molten mold flux into a mold, and comparing the optimum thickness of a predetermined molten mold flux with a measurement thickness of the molten mold flux injected into the mold are performed to melt the molten mold flux. Disclosed are a thickness control method of a molten mold flux and a thickness control apparatus of a molten mold flux including a thickness adjusting step of adjusting an injection amount of a mold flux.

Description

Thickness control method of molten mold flux and thickness control device of molten mold flux {METHOD AND APPARATUS FOR CONTROLLING THICKNESS OF MOLTEN MOLD FLUX}

The present invention relates to a thickness control method of the molten mold flux and a thickness control apparatus of the molten mold flux, and more particularly, the injection amount of the mold flux according to the casting width is injected into the mold, and the thickness of the mold flux injected into the mold is completed. The present invention relates to a thickness control method of a mold flux and a thickness control apparatus of a molten mold flux which are adjusted to be optimally maintained until a viewpoint.

In general, the continuous casting process causes the molten steel in the liquid state to be injected into the mold having the determined casting width, and then forms a solidified shell by cooling in the mold. The solidified shell in which the molten steel is cooled is solidified by the secondary coolant sprayed from the spray nozzle while being guided by the guide roll installed in the lower part of the mold to collectively refer to slabs, billets, blooms, ranks, etc. in solid state. ) Is manufactured.

As molten steel is supplied into the mold during the continuous casting operation of such steel, a subsidiary mold flux is also introduced. Mold fluxes are generally introduced in powder or molten form to control heat transfer between the molten steel and the mold and to improve lubrication.

1 is a schematic cross-sectional view showing a conventional molten mold flux supply apparatus. Referring to the drawings, in the conventional molten mold flux supply apparatus, raw materials are charged from the molten flux source 2 into the melting furnace 3, and the charged mold flux is provided with heating means 4 provided around the melting furnace 3. The molten mold flux MF is supplied to the mold 7 which is melted by the molten steel 1 and injected with the molten steel 1 in advance along the discharge nozzle 5 exposed by the stopper 6.

However, in the continuous casting process, the molten mold flux has a problem of always injecting a certain amount of mold flux even though the mold flux consumption varies depending on the casting conditions (casting width, etc.).

In addition, since the consumption amount of the mold flux changes according to various conditions even if the constant amount is always discharged from the melting furnace 3, there is a problem that it is difficult to optimally maintain the thickness of the molten mold flux MF.

In order to solve this problem, in practice, a measurer adjusts the molten mold flux thickness by directly measuring the melt mold flux value by measuring the thickness of the molten mold flux directly injected into the mold. However, there is a problem in that it is not possible to optimally adjust the thickness of the molten mold flux by such manual work.

The present invention is to solve the above problems, and provides a thickness control method of the mold flux, and a thickness control apparatus of the molten mold flux which can inject the injection amount of the molten mold flux according to the casting conditions.

In addition, the present invention provides a method for controlling the thickness of the mold flux, and a thickness control device for the molten mold flux, which can optimally maintain the thickness of the molten mold flux during continuous casting.

In the thickness control method of the molten mold flux according to an embodiment of the present invention, the molten mold flux injection step of calculating the injection amount of the molten mold flux according to the casting width and injecting it into the mold, and the optimum thickness of the preset molten mold flux and the And a thickness adjusting step of adjusting an injection amount of the molten mold flux by comparing the measured thickness of the molten mold flux injected into the mold.

In addition, the molten mold flux injection step, the first injection step of calculating the initial injection amount of the molten mold flux to be injected into the mold, and when the injection of the initial injection amount is completed, the continuous injection amount of the molten mold flux according to the casting width Comprising a second injection step of injecting into the mold.

At this time, in the second injection step, the continuous dose of the molten mold flux is calculated according to the continuous dose table of the molten mold flux according to the casting width.

In addition, the continuous injection amount of the molten mold flux is 1.1 to 1.5 times the average consumption of the molten mold flux, the average consumption of the molten mold flux satisfies the following [Equation 1].

[Relationship 1]

Average Consumption (kg / min) =-0.652 + 0.00102 x Casting Width (mm)

The thickness adjusting step may include a thickness comparison step of comparing the optimum thickness of the set molten mold flux with the thickness measurement value of the molten mold flux formed in the mold, and the melt mold formed in the mold with the optimum thickness of the set molten mold flux. Including a dose adjustment step of adjusting the continuous dose of the molten mold flux according to the difference in the thickness measurement value of the flux, the thickness comparison step and the dose adjustment step is repeated until the casting is completed.

The apparatus for controlling molten mold flux thickness according to an embodiment of the present invention includes a raw material input unit for charging mold flux raw material into a melting furnace, a tilting unit for injecting the molten mold flux into a mold by tilting the melting furnace, and It includes a thickness measuring unit for measuring the thickness of the mold flux injected into the mold, and a control unit for controlling the raw material input unit according to the molten mold flux input amount table according to the casting width.

According to the present invention, it is possible to optimally maintain the thickness of the molten mold flux by injecting the optimum mold flux injection amount according to the casting width.

In addition, by adjusting the raw material input or tilt value according to the difference between the optimum thickness of the molten mold flux and the measured thickness value, the molten mold flux may be maintained at the optimum thickness until the continuous casting is completed.

1 is a schematic view of a conventional molten mold flux feeder,
2 is a flowchart illustrating a thickness control step of a molten mold flux according to an embodiment of the present invention;
3 is a view showing the average consumption of the molten mold flux according to the casting width,
4 is a graph showing the relationship between the average consumption according to the casting width,
5 is a view showing a part of the continuous dose table according to the casting width,
6 is a schematic diagram of a molten mold flux automatic control device according to an embodiment of the present invention,
7 is a block diagram of an apparatus for automatically melting mold flux control according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Also, the drawings in the present application should be understood as being enlarged or reduced for convenience of description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

2 is a flowchart illustrating a thickness control step of a molten mold flux according to an embodiment of the present invention.

In the thickness control method of the molten mold flux according to the embodiment of the present invention, the molten mold flux injection step (S10) for injecting the molten mold flux input amount according to the casting width into the mold, and the optimum thickness and mold of the preset molten mold flux And a thickness adjusting step (S20) of adjusting the injection amount of the molten mold flux by comparing the measured thickness of the molten mold flux injected into it.

In the molten mold flux injection step S10, the first injection step S11 of injecting the initial injection amount of the molten mold flux into the mold again, and when the initial injection amount is completed, the continuous injection amount of the molten mold flux is determined according to the casting width. It is composed of a second injection step (S12) to calculate and inject into the mold.

The first injection step (S11) is a step of injecting the molten mold flux for the first time after the molten steel is injected into the mold when the continuous casting is started, according to the initial melt amount of the molten mold flux, the optimum thickness of the molten mold flux, and the casting width The initial dose of the molten mold flux is calculated.

At this time, predetermined mold flux is melt | dissolved in the melting furnace previously, and the optimum values, such as initial tilt actual input value, input time, initial injection amount, etc. are preset according to this initial melt amount. Therefore, when the user sets the initial melt amount of the molten mold flux, the optimum thickness of the molten mold flux, and the casting width, the input amount of the molten mold flux to be finally injected is automatically calculated. At this time, when the input amount of the molten mold flux is calculated, the melting furnace tilting which corresponds to the molten mold flux input amount is performed.

Table 1 below is an exemplary table for calculating the amount of melt flux to be injected when the initial melt amount of the molten mold flux is set to 80 kg, and Table 2 shows the furnace tilt value according to the amount of melt flux input. Table table.

Initial dissolution
(kg) Melt Mold Flux
Optimum thickness (mm) Casting width
(mm) Injection time
Balance L (min) 80 33 1800 1.9 Injection time
Output S (min) OP migration
Normal consumption front
powder Final injection
Melt Flux (kg) 5.9 18 6.77143 27.38143

Melting furnace tilt (mm) 48 49 50 51 52 53 54 55 Input (kg) 21 22 23 24 25 26 27 27

For example, if the optimum thickness of the molten mold flux is 33 mm, the casting width is 1800 mm, and the initial capacity is 80 kg, the molten mold flux injection amount to be injected is automatically calculated as 27.38143 kg, as shown in [Table 1]. Once determined, the furnace tilt value is automatically calculated to 54mm according to the furnace tilt value table as shown in [Table 2], and the furnace is tilted. This furnace tilt is maintained as long as the tilt value is not adjusted in the thickness adjustment step described later.

Through this step, when the initial injection amount of the molten mold flux is injected into the mold, the thickness of the molten mold flux is maintained at 33 mm input by the user. The molten mold flux injected into the mold serves as a lubricant between the mold wall and the molten steel and insulates the molten steel to maintain a predetermined temperature. The above-described molten mold flux optimum thickness is the thickness of the molten mold flux formed on the molten steel, and the casting width is the width of the mold.

Thereafter, the second injection step S12 is a step of maintaining the optimum thickness by continuously injecting the molten mold flux after the first injection step S11 is completed. Since molten steel in the mold is continuously discharged, the molten mold flux must also be continuously injected to maintain a constant thickness. Therefore, in this step, by calculating the amount of the molten mold flux consumed on the average according to the casting width and supplying it, the thickness of the molten mold flux is optimally maintained.

Specifically, as shown in FIG. 3, it can be seen that the average consumption of the molten mold flux varies depending on the type of the molten mold flux, the casting width, the casting speed, the casting time, the casting length, the cast length, and the like. It was found that the gang width was most closely related to the average consumption of the molten mold flux. Referring to FIG. 4, it can be seen that the graph of the casting width and the average consumption of the molten mold flux satisfies the following Equation 1.

[Relationship 1]

Average Consumption (kg / min) =-0.652 + 0.00102 x Casting Width (mm)

That is, the average consumption of the molten mold flux according to the casting width may be defined by a linear function, such as the above equation 1, and the linear function is used to fit the linear curve fitting method using a coordinate of the average consumption position according to the casting width. curve fitting). Such a linear curve fitting method can be applied to all known methods, and a detailed description thereof will be omitted.

According to Equation 1, it can be seen that the casting width and the average consumption have a correlation of about 80% or more. Therefore, the average consumption of the molten mold flux may be defined as determined by the casting width. Therefore, in the present invention, the molten mold flux continuous input amount is determined by controlling the raw material input amount output amount according to the casting width so as to satisfy the relation 1 above.

Referring to FIG. 5, the continuous input amount is calculated according to the continuous input amount (required input amount) table according to the casting width, and the flux raw material is charged into the melting furnace.

For example, when the casting width is 1840mm, the average consumption is 1.1877kg / min, and the continuous input amount is 1.3196666kg / min, so the flux raw material is charged into the melting furnace to control the furnace raw material input accordingly, and the charged raw material is melted. The injection into the mold allows for continuous injection.

At this time, since the raw material of the molten mold flux is generally volatile, the continuous input amount is adjusted to about 1.1 to 1.5 times the average consumption amount in consideration of the volatilized amount.

By such a configuration, the melt flux input amount according to the casting width can be adjusted, so that the melt flux thickness in the mold can be optimally maintained.

Referring back to FIG. 2, the thickness adjusting step (S20) is a step of measuring the thickness of the molten mold flux formed in the mold and comparing the thickness with a preset optimal thickness to correct the thickness.

The thickness adjusting step (S20) is, again, a thickness comparison step (S21) of comparing the measured thickness of the molten mold flux formed inside the mold with the optimal thickness of the set molten mold flux, and the optimum thickness of the set molten mold flux and the According to the difference in the measured thickness of the molten mold flux formed in the mold is divided into an input amount adjusting step (S22) (S23) for adjusting the input amount of the molten mold flux.

First, the thickness comparison step (S21) is a step of measuring the thickness of the molten mold flux injected into the mold and comparing it with a predetermined optimum thickness, the thickness of the molten mold flux injected into the mold is measured by a thickness sensor disposed on the mold. Can be performed by There is no limitation on the kind of such a sensor, and various kinds of sensors may be mounted.

The preset optimal thickness refers to a thickness capable of optimally performing the role of the molten mold flux in continuous casting, which may be input in advance by the user. In general, the thickness of the molten mold flux is 33 mm is most suitable, but is not necessarily limited to this may be appropriately changed according to the working conditions.

Then, the input amount adjustment step (S22) (S23) is a step of maintaining the molten mold flux thickness at the optimum thickness by adjusting the input amount according to the difference in the thickness value through the comparison step (S21), specifically, the molten mold flux optimum thickness And when the difference between the measured values of the thickness of the molten mold flux formed in the mold is within the setting range, the input of the melting furnace raw material is controlled (S22), and when it is out of the setting range, the melting furnace tilt value is controlled (S23). Adjust the dose.

Here, the “set range” may be defined as a thickness range in which the molten mold flux may play a role, and when out of the set range, the molten mold flux may not play a role and thus cast quality may be greatly reduced. In the present embodiment, the setting range is set to ± 5mm from the optimum thickness of the molten mold flux, but is not necessarily limited thereto and may vary according to casting conditions.

First, when the difference between the optimum thickness of the molten mold flux and the measured value of the thickness of the molten mold flux formed in the mold is within the set range, only the raw material input amount of the melting furnace is controlled to adjust the thickness. In this case, the control of the raw material input of the melting furnace reduces the amount of raw material injected into the melting furnace when the measured thickness of the molten mold flux formed inside the mold is larger than the optimum thickness of the molten mold flux, and vice versa. To adjust the injection amount of the molten mold flux.

At this time, the step (S24) to confirm the melting furnace adjustment can be performed. This confirming step may determine whether the injection amount is adjusted by checking the flow rate at which the molten mold flux is injected through the camera.

In addition, the furnace input may be subdivided according to the difference in thickness values. For example, when the difference in thickness value is 2 to 3mm difference, the raw material input power may be adjusted to ± 10%, and when the thickness difference is 4 to 5mm, the raw material input power may be adjusted to ± 20%.

Thereafter, after a predetermined period of time, the molten mold flux thickness is again measured in the mold (S25), and the input amount of the melting furnace is adjusted again. At this time, if the measured thickness of the mold flux matches the optimum thickness, the adjusted dosage is maintained as it is, and if it does not match, the raw material input output is adjusted again according to the thickness difference.

If the difference between the optimum thickness of the molten mold flux and the measured value of the thickness of the molten mold flux formed in the mold is out of the setting range, the melting furnace tilt value is controlled (S23) to adjust the thickness. If the thickness difference is out of the setting range, there is a high risk of relatively poor casting quality, so urgently adjust the thickness by adjusting the furnace tilt value.

In this case, the input of the furnace may be fixed in order to facilitate the thickness control according to the adjustment of the furnace tilt value. However, when the input power of the furnace is less than 35%, the injected raw material or the molten mold flux is hardened. If the input is more than 75%, the molten mold flux is not properly melted in the furnace. It is fixed in%.

Thereafter, after a predetermined period of time, the molten mold flux thickness is again measured in the mold (S25), and the amount of the melting furnace is adjusted again. At this time, if the thickness difference is within the setting range, the raw material input amount is controlled (S22) to adjust the thickness difference, and when it is out of the setting range, the tilt value is adjusted again (S23).

This step is repeated until the combustion casting is completed by determining whether the continuous casting is completed (S26). According to the embodiment of the present invention, while injecting the most optimal continuous dose according to the casting width, the raw material input amount or tilt value is additionally adjusted according to the thickness difference, so that the molten mold flux is adjusted to the optimum thickness until the continuous casting is completed. I can keep it.

In addition, if the casting width is changed during continuous casting, the furnace input is kept to a minimum during the time that the casting width is changed, and when the casting width is changed, the continuous dose is injected according to the changed casting width and the thickness adjustment step is performed again. Can be. In this case, the minimum input amount may be performed by adjusting the raw material input amount to 35%.

6 is a schematic diagram of a molten mold flux automatic control apparatus according to an embodiment of the present invention, Figure 7 is a block diagram of a molten mold flux automatic control apparatus according to an embodiment of the present invention.

The thickness control apparatus of the molten mold flux according to the embodiment of the present invention, the raw material input unit 100 for charging the mold flux raw material into the melting furnace 200 and the molten mold flux melted in the melting furnace by tilting the melting furnace 200 Tilt portion 300 to be injected into the mold 500, a thickness measuring unit 520 for measuring the thickness of the mold flux injected into the mold 500, and a molten mold flux input amount table according to the casting width (W) The control unit 400 for controlling the raw material input unit 100 according to.

The raw material input part 100 is provided with a gate valve 120 and a nozzle 130 under the plurality of raw material bins 110, and when the raw material input amount control signal is received by the controller 400, the raw material as much as the controlled amount is melted in the furnace. Charge in. The melting furnace 200 is equipped with a heating means (not shown) such as a heater on the side wall to melt the charged mold flux, and the discharge port 210 is formed on the side wall to form a predetermined amount of the molten mold flux according to the tilt value. Is injected into.

The tilting unit 300 tilts the melting furnace 200 such that the molten mold flux produced in the melting furnace 200 is discharged through the discharge port 210. In detail, the tilting part 300 includes a rotating shaft 310 provided at the side or the bottom and a driving part 320 that provides a driving force for rotating the melting furnace 200 based on the rotating shaft 310.

The controller 400 controls the raw material input unit 100 and the tilting unit 300 to adjust the amount of molten mold flux dissolved in the melting furnace 200 and the amount of molten mold flux discharged. Specifically, the control unit 400 calculates the continuous input amount to be injected into the mold according to the molten mold flux input amount table (see FIG. 5) according to the casting width W stored in the memory unit 420. Control the eastern 300.

Thereafter, the control unit 400 receives the thickness information of the molten mold flux formed in the actual mold 500 by the thickness measuring unit 520 and compares it with the optimum thickness input through the input unit 410.

As a result of the comparison, if the thickness difference is within the preset range, the amount of molten mold flux injected into the mold is controlled by controlling the raw material input unit 100 while maintaining the tilt value, and when the thickness difference is out of the set range, the tilt value is adjusted. Adjust the amount of melt mold flux.

Specifically, the control unit 400 outputs a control signal to the raw material input unit 100 so as to reduce the raw material input when the measured value of the molten mold flux thickness formed inside the mold is larger than the molten mold flux optimum thickness, and vice versa. In this case, a control signal is output to the raw material input part 100 so that the raw material input increases.

In addition, when the molten mold flux thickness measurement value formed inside the mold is greater than the molten mold flux optimum thickness, a control signal is output to the tilting unit 300 so as to decrease the tilt value, and vice versa. Outputs a control signal to the tilting unit 300 to.

In addition, since the specific control method is the same as described above, further description will be omitted.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having various ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. And additions should be considered to be within the scope of the following claims.

100: raw material input part 200: melting furnace
300: tilting part 400: control unit
500: mold 520: thickness measurement unit

Claims (14)

A molten mold flux injection step of injecting the molten mold flux input amount into the mold according to the casting width; And
And a thickness adjusting step of adjusting an injection amount of the molten mold flux by comparing an optimum thickness of a predetermined molten mold flux with a measurement thickness of the molten mold flux injected into the mold.
The molten mold flux injection step,
A first injection step of injecting an initial dose of molten mold flux into the mold; And
And a second injection step of injecting the continuous injection amount of the molten mold flux according to the casting width into the mold when the injection of the initial injection amount is completed, wherein the initial injection amount is an initial dissolution amount of the molten mold flux and a molten mold flux. Is calculated according to the optimum thickness, and casting width,
In the thickness adjusting step, when the difference between the optimum thickness of the molten mold flux and the measured value of the thickness of the molten mold flux formed in the mold is within a setting range, the furnace raw material input amount is controlled. Method of controlling thickness of molten mold flux to be controlled. delete delete The method of claim 1,
Melting mold flux thickness control method that the melting furnace tilt value is adjusted according to the calculated initial dose. The method of claim 1, wherein in the second injection step,
And a continuous injection amount of the molten mold flux is calculated according to a continuous loading table of the molten mold flux according to the casting width. The method of claim 1, wherein in the second injection step,
Continuous injection amount of the molten mold flux is 1.1 to 1.5 times the average consumption of the molten mold flux, the average consumption of the molten mold flux molten mold flux thickness control method satisfying the following [Equation 1].
[Relation 1]
Average Consumption (kg / min) =-0.652 + 0.00102 x Casting Width (mm) delete delete According to claim 1, In the dose adjustment step,
The melting furnace raw material input control reduces the amount of raw material injected into the melting furnace when the measured value of the molten mold flux formed in the mold is larger than the optimum thickness of the molten mold flux, and vice versa Melt mold flux control method for controlling the amount of molten mold flux input by increasing. According to claim 1, In the dose adjustment step,
The melting furnace tilt value control reduces the melting furnace tilt value when the molten mold flux thickness measurement value formed inside the mold is larger than the optimum melting mold flux thickness, and vice versa by increasing the melting furnace tilt value to input the molten mold flux. Melt mold flux thickness control method to control the. A raw material input unit for charging a mold flux raw material into the melting furnace;
A tilting unit for tilting the melting furnace to inject the molten mold flux into the mold;
A thickness measuring unit measuring a thickness of the mold flux injected into the mold; And
And a control unit for controlling the raw material input unit according to a molten mold flux input table according to a casting width.
The control unit compares the thickness of the mold flux measured by the thickness measuring unit with a preset mold flux optimum thickness, and controls the raw material input unit when the thickness difference is within a setting range, and controls the tilting unit when it is out of the setting range. Thickness control device of the molten mold flux. delete 12. The method of claim 11,
The control unit outputs a control signal to the raw material input unit so that the raw material input is reduced if the molten mold flux thickness measurement value formed inside the mold is greater than the molten mold flux optimum thickness, and vice versa Melting mold flux thickness control device for outputting a control signal to the raw material input unit. 12. The method of claim 11,
The control unit outputs a control signal to the tilting unit to decrease the tilting value when the measured value of the molten mold flux thickness formed inside the mold is greater than the molten mold flux optimum thickness, and increases the tilting value to increase the tilting value. Melt mold flux thickness control device for outputting a control signal to the tilting portion.

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