WO2017150787A1 - Device for injecting molten material, casting equipment using same, and casting method - Google Patents

Abstract

The present invention relates to a device for injecting a molten material, casting equipment using the same, and a casting method, which comprises the steps of: preparing a main mold flux; injecting molten steel into a mold; preparing a molten mold flux by melting the main mold flux, and injecting the molten mold flux into an upper part of the molten steel; casting a slab; and determining whether to inject an additive according to a cast state in the step of casting the slab, and the present invention improves the quality and productivity of the slab.

Description

Melt injection device, casting equipment and casting method using the same

The present invention relates to a melt injection device, a casting facility and a casting method using the same, and more particularly to a melt injection device, a casting facility and a casting method using the same that can improve the quality and productivity of the cast steel.

A melt injection device, such as a molten mold flux injection device, used in a casting process of cast steel is an equipment for melting and supplying a mold flux, which is powder. Conventional molten mold flux injection facilities include a hopper in which mold flux is stored, a melting furnace for receiving mold flux from the hopper and melting, and a torch provided on one side of the melting furnace to inject flame into the melting furnace to dissolve the mold flux. . At this time, the discharge furnace may be formed in the melting furnace to discharge the molten molten flux.

By dissolving and supplying the mold flux to the mold in this way, the temperature drop of the molten steel in the mold can be suppressed, and the lubrication performance can be improved to reduce the cast defect.

However, in the case of casting a slab by melting a mold flux manufactured to have a characteristic component for each steel grade in a melting furnace, a phenomenon in which a component of the mold flux changes due to a reaction between impurities contained in the steel and the mold flux occurs. For example, when casting using molten steel containing a large amount of Al, the viscosity of the mold flux increases as Al2O3 is picked up to the mold flux. As a result, the mold flux does not flow smoothly between the mold and the slab (coagulation cell), resulting in uneven heat transfer between the molten steel and the mold. Will occur.

Due to such a change in the physical properties of the mold flux, there is a problem that it is difficult to perform a multi-ply casting of a single steel grade.

On the other hand, in the case of multiple performance of several steel grades, mold flux of suitable physical properties should be used whenever steel grades are changed. Therefore, when the steel grade is changed, it is necessary to inject a mold flux manufactured to have suitable physical properties into the mold. By the way, when supplying the mold flux according to the steel type, it is good not to mix the mold flux having different physical properties, but due to the process characteristics, the transition between the mold fluxes having different physical properties are inevitably generated. In such a transition, mold flux does not flow smoothly between the mold and the coagulation cell, which causes a phenomenon in which the coagulation cell bursts.

The present invention provides a melt injection apparatus, a casting facility and a casting method using the same that can improve the casting efficiency.

The present invention provides a melt injection apparatus, a casting facility and a casting method using the same that can improve the quality of the cast steel.

Melt injection apparatus according to an embodiment of the present invention, the raw material supply unit for supplying different kinds of raw materials; A mixing unit for preparing a mixture by mixing different kinds of raw materials supplied from the raw material supply unit; A melting part connected to the mixing part to melt a mixture supplied from the mixing part to generate a melt, and a discharge port through which the melt is discharged is provided; And a control unit for controlling the components of the mixture by controlling operations of the raw material supply unit, the mixing unit, and the melting unit.

The raw material supplier may include a first raw material supplier for supplying a first raw material and a second raw material supplier for separately supplying a plurality of second raw materials having different components.

The first raw material supply unit, a first storage unit for storing the first raw material; A first conveying pipe connecting the first reservoir and the mixing part; And a first cutting machine provided in at least one of the first reservoir and the first transfer pipe to adjust the discharge of the first raw material.

The second raw material supply unit, a plurality of second storage for storing the plurality of second raw materials, respectively; A second transfer pipe connecting the plurality of second reservoirs and the mixing unit, respectively; And a second cutting machine provided in at least one of the second reservoir and the second transfer pipe to adjust the discharge of the second raw material.

The mixing unit and the mixing vessel in communication with the first supply pipe and the second supply pipe; An agitator provided in the mixing vessel to mix the first raw material and the second raw material; And a third transfer pipe configured to transfer the mixture of the first raw material and the second raw material to a melting part.

The mixing unit may include a mixing container in communication with the first supply pipe and the second supply pipe, and the mixing container may be rotatable.

The melting part, the melting furnace having a melting space in which the first raw material and the second raw material is received and dissolved; And a heat source supply unit provided at one side of the melting furnace to supply a heat source to the melting space.

The heat source supply unit may use plasma as a heat source.

The controller may control whether or not the second raw material is added according to the input signal.

According to an aspect of the present invention, there is provided a casting apparatus, comprising: a mold configured to receive molten steel for initial solidification; A melt injection device for injecting a molten mold flux into the mold; A measuring unit measuring at least one of a temperature of the mold and a component of a molten mold flux injected into the mold; And a controller configured to control an operation of the melt injection apparatus to change a component of a molten mold flux injected into the mold according to the measurement result of the measurement unit.

The melt injection device includes a first raw material supply unit for supplying the main mold flux; A second raw material supplier for supplying an additive; A mixing unit for mixing the main mold flux supplied from the first raw material supply unit and the second raw material supply unit and the additive to prepare a mixture; And a melting part for dissolving the mixture supplied from the mixing part to generate a molten mold flux and injecting the molten mold flux into the mold.

The second raw material supply unit may individually store a plurality of additives, and selectively supply the plurality of additives to the mixing unit.

The measuring unit may include a temperature measuring device for measuring the temperature of the mold.

The measurement unit may include a probe for collecting the molten mold flux injected into the mold, and an analyzer for analyzing the components of the molten mold flux collected by the probe.

The controller may determine whether the additive is added using the result measured by the measuring unit, and control the second raw material supply unit according to the result to adjust the type and amount of the additive.

A casting method according to an embodiment of the present invention, comprising: providing a main mold flux; Injecting molten steel into the mold; Melting the main mold flux to produce a molten mold flux and injecting the molten mold flux into the molten steel; Casting of cast steel; And determining whether or not to add an additive according to a casting state in the process of casting the cast steel.

In the process of preparing the main mold flux, the additive may be provided.

In the process of manufacturing the molten mold flux by melting the main mold flux, the main mold flux and the additive may be melted together.

In the casting of the cast steel, the temperature of the mold may be measured as the casting state, and whether or not the additive is added may be determined according to the measured temperature value of the mold.

In the casting of the cast steel, the components of the molten mold flux injected into the mold as the cast state may be analyzed, and the additive may be determined according to the components of the molten mold flux analyzed.

When the addition of the additive is determined, the main mold flux and the additive may be mixed and melted to inject the molten mold flux having the changed component into the mold.

When the type of molten steel injected into the mold is changed in the process of casting the cast steel, the molten mold flux having the component changed may be injected into the mold by mixing and melting the main mold flux and the additive.

When the main mold flux and the additive are mixed, additives of different components may be added according to the type of molten steel.

When the main mold flux and the additive are mixed, the dosage of the additive having the same component may be changed according to the type of the molten steel.

According to embodiments of the present invention, it is possible to quickly respond to changes in the composition of the mold slag during casting to improve casting efficiency and cast quality. That is, additives for controlling the components of the mold slag during casting may be added to respond to changes in the components of the mold slag in real time. Therefore, cracks on the surface of the slab and bursting of the solidification cell due to the change of the components of the mold slag can be prevented, thereby improving the quality of the slab. In addition, it is possible to perform a continuous cast of a single steel grade to improve the productivity.

In addition, when performing the cast of several steel grades, the molten mold flux suitable for the steel grade can be quickly manufactured and supplied, thereby improving casting efficiency. Therefore, it is possible to reduce the time for the molten mold flux having different physical properties to be mixed and to suppress or prevent occurrence of bursting of the cast steel.

1 is a view schematically showing a casting facility according to an embodiment of the present invention.

Figure 2 is a view showing the main configuration of the casting equipment shown in FIG.

Figure 3 is a block diagram showing the configuration of the casting equipment shown in FIG.

4 is a flowchart sequentially showing a casting method according to a first embodiment of the present invention.

FIG. 5 is a block diagram conceptually showing a method of injecting molten mold flux into a mold when casting a slab by a casting method according to a second exemplary embodiment of the present invention. FIG.

Figure 6 is a graph showing the results of experiments depending on whether the additive is added when casting the cast in the casting method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention and to those skilled in the art. It is provided for complete information.

1 is a view schematically showing a casting facility according to an embodiment of the present invention, Figure 2 is a view showing the main configuration of the casting facility shown in Figure 1, Figure 3 is a configuration of the casting facility shown in FIG. A block diagram showing.

Referring to FIG. 1, a casting apparatus according to an exemplary embodiment of the present invention supplies a molten steel through a ladle 10 containing molten steel refined in a steelmaking process and an injection nozzle (not shown) connected to the ladle 10. A mold 30 for receiving and temporarily storing it and supplying molten steel through an immersion nozzle 22 connected to the tundish 20 and supplying the mold 30 to the mold 30, and initially solidifying the mold 30 in a predetermined shape; It may include a cooling line 40 provided in the lower portion of the mold 30 and a plurality of segments are continuously arranged to perform a series of molding operations while cooling the non-solidified slab 1 drawn from the mold 30. .

2 and 3, the casting apparatus includes a melt injection apparatus 100 for melting and supplying a mold flux to a molten steel surface supplied to a mold 30, and a component change of a mold flux in the mold 30. It may include a measuring unit 130 for measuring various phenomena according to, and a control unit 140 for controlling the operation of the melt injection device 100 according to the measurement result of the measuring unit 130.

The melt injection apparatus 100 may supply a solid mold flux, ie, a molten mold 30, to the mold 30 by melting the solid mold flux. In the related art, the melt injection apparatus is melted in real time with a heating means such as a plasma torch and supplied to the mold 30 as it is, so that the mold 30 provided to have a specific component according to the steel type. However, even when the molten mold 30 supplied in the mold 30 reacts with impurities in molten steel during casting, and the component thereof is changed, the melt injection apparatus continues to supply the mold 30 having the same component. It was not possible to respond in real time to changes in the composition.

In addition, in the case of performing the performance of the different steel grades, since the mold 30 of different components is provided according to the steel grade, it takes time to change to the mold 30 having a component suitable for the steel grade, and different in the melting furnace 112. Since the mold 30 of the components are inevitably mixed, problems such as the solidification cell bursting phenomenon may occur because the mold 30 cannot be smoothly injected between the mold 30 and the solidification cell.

Accordingly, in the present invention, in order to solve the problems of the melt injection device described above, the melt injection device 100 is configured to change the components of the melt mold 30 supplied to the mold 30 in real time. Hereinafter, in referring to the mold flux, the solid mold flux is called mold flux before being supplied to the melting furnace 112, and the molten mold flux is called after melting the solid mold plus in the melting furnace 112. In addition, after injecting the molten mold flux into the mold 30, the mold slag.

The melt injection apparatus 100 according to the embodiment of the present invention generates a molten mold flux by supplying and dissolving a raw material supply unit 110 supplying a solid mold flux and a solid mold flux, and forming the molten mold flux into a mold ( 30 may include a melting unit 120, a raw material supply unit 110, and a control unit 140 controlling the operations of the melting unit 120.

The raw material supply unit 110 includes a first raw material supply unit 112 for supplying a first raw material, a second raw material supply unit 114 for supplying a second raw material, a first raw material supply unit 112, and a second raw material supply unit 114. And a mixing unit 116 which is connected to the first raw material supply unit 112 and the second raw material supply unit 114 to mix the first raw material and the second raw material to produce a mixture of the first raw material and the second raw material; It may include. In addition, the raw material supply unit 110 may supply a mixture of the first raw material and the second raw material to the melting unit 120 through the mixing unit 116, but between the mixing unit 116 and the melting unit 120 It may also include a raw material feeder 118 that can constantly supply the raw material or a mixture of the first raw material and the second raw material to the melting unit (120).

The first raw material supply part 112 includes a first reservoir 112a for storing a first raw material, for example, a main mold flux, and a first transfer pipe 112b for communicating the first reservoir 112a and the mixing unit 116. ) May be included.

The first reservoir 112a stores the first raw material in the solid state, for example, the main mold flux. The first cutting machine 112c for discharging the main mold flux to the first transfer pipe 112b by a predetermined amount or uniformly in the portion where the main mold flux is discharged from the first reservoir 112a or the first transfer pipe 112b. ) May be provided. In this case, the first cutting machine 112c may be a screw feeder provided in the first reservoir 112a or the first transfer pipe 112b and operated by the operation of the driving device. It may be a valve for opening and closing the connection portion of the first transfer pipe (112b) or the flow path inside the first transfer pipe (112b).

The second raw material supplier 114 includes a second reservoir 114a for storing a second raw material, for example, an additive, and a second transfer pipe 114b for communicating the second reservoir 114a with the mixing unit 116. It may include. In this case, a plurality of second reservoirs 114a may be provided to independently store various types of additives. The second ejector 114c for discharging the additive to the mixing unit 116 by a predetermined amount or uniformly may be provided in the portion where the additive is discharged from each second reservoir 114a or the second transfer pipe 114b. The second cutting machine 114c may be a screw feeder provided in the first reservoir 112a or the second transfer pipe 114b and operated by the operation of the driving device, or the second reservoir 114a. And it may be a valve for opening and closing the connection portion of the second transfer pipe (114b) or open and close the flow path inside the second transfer pipe (114b).

Through this configuration, the second raw material supply unit 114 may selectively supply at least one additive of the plurality of additives.

The mixing unit 116 may supply a mold flux in which the main mold flux discharged from the first raw material supply unit 112 and the second raw material supply unit 114 and the additive is uniformly mixed to the melting unit 120. In addition, the mixing unit 116 may supply only the first raw material supplied from the first raw material supply unit 112 to the melting unit 120. The mixing unit 116 may include a main container flux supplied from the first raw material supply unit 112 and a second raw material supply unit 114, a mixing container 116a for receiving additives, and a main mold flux housed in the mixing container 116a. And an agitator (not shown) for uniformly mixing the additives, and a third transfer pipe 116b for transferring the mixture of the main mold flux and the additive, that is, the mold flux to the melter 120.

The mixing container 116a may accommodate the main mold flux and the additive in the solid state discharged from the first raw material supplier 112 and the second raw material supplier 114. A portion in which the mixture of the main mold flux and the additive is discharged from the mixing container 116a, or a third cutting machine for discharging the mixture of the first raw material and the second raw material by a predetermined amount or uniformly in the third transfer pipe 116b ( 116c). At this time, the third cutting machine 116c may be a screw installed in the mixing vessel 116a or the third transfer pipe 116b and operated by driving of the motor, and the mixing vessel 116a and the third transfer pipe 116b. It may be a valve for opening and closing the connection portion of the) or opening and closing the flow path inside the third transfer pipe (116b).

The stirrer may be formed of a screw or an impeller configured to be rotatable in the mixing container 116a. In addition, the stirrer may be a nozzle capable of blowing an inert gas or the like into the mixing vessel 116a.

Although the mixing unit 116 is described as being configured to include the mixing vessel 116a and the agitator, the mixing vessel 116a may be configured to be rotatable so that the main mold flux and the additive may be uniformly mixed without the agitator. . The mixing unit 116 is not limited thereto and may be formed in various forms capable of uniformly mixing the main mold flux and the additive.

In addition, the mixing unit 116 may include a heater 116d for preheating the main mold flux or the mixture of the main mold flux and the additive. The heater 116d may be provided in the stirrer or the mixing vessel, and the main mold flux or the mixture of the main mold flux and the additive may be heated to a predetermined temperature and supplied to the raw material feeder 118.

The raw material feeder 118 connects the third reservoir 118a communicating with the third transfer pipe 116b of the mixing unit 116, the third reservoir 118a and the melter 120, and an internal flow path thereof. The fourth feed pipe 118b for supplying the first raw material or the mixture of the first raw material and the second raw material through the inside of the third reservoir 118a or the fourth transfer pipe 118b through the first raw material or A fourth cutting machine 118c may be provided to discharge the mixture of the first raw material and the second raw material to the melting part 120 by a predetermined amount or uniformly. The fourth cutting machine 118c is also provided in the third reservoir 118a or the fourth transfer pipe 118b like the first to third cutting machines 112c, 114c, and 116c described above, and is operated by the driving device. It may be a working screw feeder or valve.

In addition, the raw material supplier 118 may include a heater 118d for preheating the main mold flux or the mixture of the main mold flux and the additive supplied from the mixing unit 116. The heater 118d may be provided in the third reservoir 118a or the fourth transfer pipe 118b. The heater 118d may be heated to a predetermined temperature to supply the main mold flux or the mixture of the main mold flux and the additive to the molten part 120. Can be. This facilitates the dissolution of the main mold flux or the mixture of the main mold flux and the additive, thereby more quickly responding to the component change of the mold slag.

The molten part 120 generates and temporarily stores a molten mold flux by heating and melting a mold flux supplied from the mixing unit 116, that is, a mixture of a main mold flux and an additive, and discharges the molten mold flux. 30). The melting unit 120 may include a melting furnace 112 in which the mixture supplied from the mixing unit 116 is accommodated, and a heat source supply unit 128 supplying a heat source into the melting furnace 112.

The melting furnace 112 has a dissolving space in which the main mold flux and the additive are injected and dissolved therein, and a discharge hole 126 for injecting the molten mold flux into the mold 30 may be formed at one side thereof. The melting furnace 112 is formed in a substantially "V" shape in which the center is bent downward, and may be provided to be tiltable. The melting furnace 112 has an injection hole 124 for injecting the mold flux discharged from the mixing unit 116 into the dissolution space, and a discharge hole 126 for injecting the molten mold flux generated in the dissolution space into the mold 30. ) May be included. The heat source supply unit 128 may be connected to one side of the melting furnace 112 to supply a heat source to the melting space. The heat source is supplied from one side of the melting furnace 112 to melt the mold flux in the melting space to generate and temporarily store the molten mold flux, and the molten mold flux is discharged through the outlet 126 on the other side to be injected into the mold 30. Can be. This is possible because the melting furnace 112 is configured to be tiltable, and the discharge amount of the molten mold flux temporarily stored in the melting space can be adjusted according to the degree of tilt of the melting furnace 112.

The heat source supply unit 128 may include a gas supply pipe that supplies a plasma gas such as nitrogen (N ₂ ), argon (Ar), helium (He), and the like to the plasma torch and the plasma torch. The plasma torch is a device for generating a plasma having a high temperature of 20,000 ° C. or more using electricity. The plasma torch generates plasma in a melting space of the melting furnace 112. The plasma torch may include a plasma confinement tube in which the plasma gas supplied from the gas supply tube is accommodated, an induction coil disposed around the plasma confinement tube, and a power supply for supplying power to the induction coil. When power is applied to the induction coil from the power supply, plasma is generated inside the plasma confinement tube. The generated plasma and the heat generated by the plasma may be used as a heat source for dissolving the mixture, that is, the solid mold flux and the additive, which is supplied to the dissolution space through the injection hole 124. The molten mold flux of the melting space may be temporarily stored in the melting space and then discharged through the discharge port 126 to be injected into the mold 30 when the melting furnace 112 is tilted.

Melting furnace 112 constituting the melter 120 may be formed in various shapes in addition to, and can be discharged of the molten mold flux in various ways, of course. Such a melting part 120 is a well-known technique, and a detailed description thereof will be omitted.

Through such a configuration, the melt injection apparatus 100 may inject and mold the components of the mold flux in real time by controlling and dissolving the components of the mold flux.

In addition, the measuring unit 130 may be provided in the mold 30 and may be a temperature measuring device for measuring the heat transfer behavior of the mold 30 or a probe for measuring the component of the mold flux injected into the mold 30. .

When the temperature measuring device is used as the measuring unit 130, the temperature measuring device may be installed in the mold 30 to measure a temperature change of the mold 30. For example, in the case of multi-casting a single steel, Al ₂ O ₃ is introduced into the mold slag after a certain period of time after casting, thereby increasing the viscosity of the mold slag. The mold slag flows unevenly between the mold 30 and the coagulation cell, and lubrication is not performed properly. Due to this effect, heat transfer from the coagulation cell to the mold 30 is not made uniformly, resulting in a deviation in the temperature value measured by the temperature measuring instrument. Therefore, casting performance may be improved by changing the components of the molten mold flux to be injected into the mold 30 in accordance with the temperature value measured by the temperature gauge and injecting the mold 30 into the mold 30.

In addition, in the case of using the probe as the measuring unit 130, a part of the mold slag in the mold 30 is collected, and the molten mold flux and the mold injected into the mold 30 by analyzing the components of the mold slag collected through the probe. The components of the slag can be compared and analyzed. Accordingly, the casting performance may be improved by changing the components of the molten mold flux to be injected into the mold 30 in order to change the components of the mold slag during casting and injecting the mold 30 into the mold 30.

As described above, the content of mixing the additive in the mold flux using the measurement result of the measuring unit 130 will be described again in the description of the casting method.

The control unit 140 receives the measurement result of the measuring unit 130 and controls the operation of the raw material supply unit according to the measurement result to adjust the supply amount of the main mold flux and the additives to the component of the molten mold flux injected into the mold 30. Can be controlled. In addition, the controller 140 may control the operation of the melting unit 120 and the measuring unit 130 to adjust the supply amount of the molten mold flux injected into the mold 30 according to the measurement result.

Hereinafter, a casting method according to an embodiment of the present invention will be described.

The casting method according to the present invention may include a first embodiment of casting a cast steel using a single steel species and a second embodiment of casting a cast steel using two steel grades.

4 is a flowchart sequentially showing a casting method according to a first embodiment of the present invention.

First, a first embodiment of casting a cast steel using a single steel grade will be described.

In the casting method according to the first embodiment of the present invention, a process of preparing a main mold flux and an additive (S110), a process of injecting molten steel through the ladle 10, the tundish 20 into the mold 30 (S120). ), The process of injecting the molten mold flux to the upper portion of the molten steel injected into the mold 30 (S130), the process of measuring the casting state (S140) and the analysis of the casting state to determine whether the additive is added (S150) and then the additive It may include a process of injecting (S160). Injecting molten steel into the mold 30 and injecting molten mold flux may be continuously performed during casting. In addition, the process of measuring the casting state and the process of injecting the additive may be repeatedly performed during the casting process by the process of determining the completion of the casting (S170).

Hereinafter, the molten mold flux injected into the mold 30 at the initial stage of casting is referred to as the first molten mold flux, and the molten mold flux mixed with the additive during casting is injected into the mold 30 as the second molten mold flux.

In the process of preparing the main mold flux and the additive, the solid main mold flux is provided in the first reservoir 112a, and the additive to be mixed with the main mold flux during casting is provided in the second reservoir 114a. In this case, the molten mold flux may include CaO, SiO ₂ , MnO, P ₂ O ₅ , Al ₂ O ₃ , MgO, TiO ₂ , K ₂ O, Na ₂ O, F, Fe ₂ O ₃ , and the like. The main mold flux may be manufactured to have a composition suitable for the molten steel used for casting. And the additives are NaF (S), Na ₃ AlF ₆ , CaF ₂ (S), AlF ₃ (s), SiO ₂ (s), Li ₂ O (s), LiF (s), CaO, MnO, P ₂ O ₅ , MgO, Al ₂ O ₃ (s), TiO ₂ , Fe ₂ O ₃ , K ₂ O (s), Na ₂ O (s), or any one of C, or may be a mixture of at least two components. .

In the process of injecting molten steel into the mold 30, the refining is completed in the refining process, and the molten steel accommodated in the ladle 10 is supplied to the tundish 20 through the injection nozzle, and the molten steel supplied to the tundish 20 is turned. It is injected into the mold 30 through the immersion nozzle 22 provided in the dish (20).

When molten steel is injected into the mold 30 to some extent, the first molten mold flux is injected into the molten steel in the mold 30. The first molten mold flux may be manufactured by melting the main mold flux stored in the first reservoir 112a through the mixing vessel 116a of the mixing unit 116 in the melting unit 120. The first molten mold flux injected at the beginning of casting may be manufactured by dissolving only the main mold flux in the melter 120.

As such, the molten steel and the first molten mold flux may be injected into the mold 30 to cast the cast steel. The first molten mold flux, ie, the mold slag, injected into the mold 30 flows in between the mold 30 and the solidification cell (or molten steel) to control heat transfer between the mold 30 and the solidification cell, and lubricate to Smooth casting.

The mold slag in the initial casting retains its components when injected, but as the casting proceeds, impurities in the molten steel flow into the mold slag, thereby changing the components of the mold slag. For example, when Al ₂ O ₃ in molten steel flows into the mold slag, the viscosity of the mold slag increases. In this case, the mold slag does not flow smoothly between the mold 30 and the solidification cell, so that the mold slag flows unevenly in the width direction and the longitudinal direction of the mold 30.

Due to this effect, heat transfer is unevenly formed between the mold 30 and the coagulation cell, so that the coagulation cell is not properly formed, and thus, a surface defect is formed on the cast steel after casting, or a cast rupture phenomenon occurs.

Accordingly, by injecting the second molten mold flux, which is produced by mixing and melting the main mold flux and the additive during the casting, into the mold 30, the mold slag flows uniformly between the mold and the solidification cell in response to changes in the composition of the mold slag. It is possible to improve the quality of the cast.

Whether the additive is added may be determined according to the casting state, for example, the temperature change of the mold 30 or the component change of the mold slag.

The temperature change of the mold 30 may be measured during casting, and an appropriate amount of an additive is mixed with the mold flux according to the measured temperature change, followed by melting and injecting the mold 30 into the mold 30, thereby rapidly responding to a component change of the mold slag. Therefore, the mold slag can be uniformly introduced between the mold 30 and the solidification cell to maintain the same heat transfer characteristics and lubrication performance as the initial casting until the casting is completed.

Temperature measurement of the mold 30 is installed in the mold 30 in the longitudinal direction and the width direction of the mold 30, and the temperature value in the longitudinal direction and / or the width direction of the mold 30 It can be measured. Then, the deviation of the temperature value measured by the temperature meter can be measured. If the measured temperature value is within the deviation range of more than 0 to about 5% from the initial measured temperature value, casting can proceed as it is. Alternatively, if the measured temperature value is out of the above-described deviation range, the addition of the additive may be determined.

As a result of the comparison, when the measured temperature value falls within the deviation range, it is determined that the mold slag is uniformly injected between the mold 30 and the solidification cell and that the change in the composition of the mold slag is insignificant. The first molten mold flux is injected into the mold 30.

However, when the measured temperature value is out of the deviation range, it is determined that a large change in the components of the mold slag occurs, so that the molten mold flux into which the additive is added, that is, the second molten mold flux, may be injected into the mold 30.

Selection of the additive to be added to the mold 30 may be selected as follows.

In the initial stage of casting, there is little change in the composition of the mold slag, so that the temperature value measured from the temperature gauge changes within a certain range. However, as the casting proceeds, impurities in the molten steel flow into the mold slag, thereby causing a change in the composition of the mold slag. For example, Al ₂ O ₃ may be introduced into molten steel or fluorine (F) component may be volatilized in the mold slag to increase the viscosity of the mold slag. In this case, the mold slag does not uniformly flow between the mold 30 and the coagulation cell, so that the heat transfer performance is lowered, thereby causing a change in the temperature value measured by the temperature measuring device installed in the mold 30. In such a case, the mold flux and the additive are mixed and melted, and then injected into the mold 30 to suppress or prevent a decrease in casting efficiency due to a change in component of the mold slag. When a large amount of Al ₂ O ₃ is introduced into the mold slag, at least one of NaF, CaF ₂ , Li ₂ CO _3, etc. may be used as an additive, and when fluorine is volatilized in the mold slag, Na ₃ AlF ₆ , NaF, etc. At least one of them can be used. In this case, since the viscosity of the mold slag in the mold 30 may be lowered to some extent, the mold slag may be uniformly injected between the mold 30 and the solidification cell. For example, when injecting molten mold slag at 1 kg / min, Na ₃ AlF ₆ may be added at 50 g / min as an additive. That is, it can be added in the range of 1 to 5% by weight based on the total weight of the molten mold slag. In this case, the fluorine content of the components of the mold slag injected into the mold 30 increases by about 2.7% by weight, and the viscosity of the mold slag is increased, thereby allowing the mold slag to smoothly flow between the mold and the solidification cell. On the other hand, Al ₂ O ₃ and Na ₂ O component is also slightly increased within the range of more than 0 to 2% by weight. Al ₂ O ₃ and Na ₂ O content of the change does not significantly affect the casting mimihayeo than the fluorine content changes.

In addition to the additives, at least one of the various types of additives described above may be used.

Mixing of the main mold flux and the additive is performed through the control unit 140, and the control unit 140 receives the result measured by the measuring unit 130, for example, the temperature measuring device, and the first cutting machine of the first raw material supply unit 112. 112c and the main mold flux and the additives stored in the first reservoir 112a and the second reservoir 114a by controlling the operation of the second cutter 114c of the second raw material supply unit 114, respectively. It is supplied to the mixing container 116a of the part 116.

Thereafter, the controller 140 operates the stirrer of the mixing unit 116 to uniformly mix the main mold flux and the additives supplied to the mixing container 116a. When the main mold flux and the additive are uniformly mixed, the control unit 140 operates the third extruder 116c of the mixing unit 116 to transfer the mixture of the main mold flux and the additive to the melting furnace 112 of the melting unit 120. Inject.

The mixture injected into the melting furnace 112 is melted by heat provided from the heat source supplying part 128 of the melting part 120, that is, plasma, and manufactured into the second molten mold flux. The second molten mold flux thus prepared is injected into the mold 30 through the discharge port 126 formed in the melting furnace 112 by tilting the melting furnace 112 and mixed with the mold slag. This lowers the viscosity of the mold slag in the mold 30 can be uniformly introduced between the mold 30 and the coagulation cell.

As described above, by continuously monitoring the temperature of the mold 30 in the process of casting the cast steel, the quality of the cast steel can be improved by quickly responding to the temperature change of the mold 30 due to the change of the components of the mold slag. Component control of the mold slag during casting may be repeatedly performed a plurality of times according to the measurement result by the measuring unit 130. Therefore, since the components of the mold slag can be controlled in response to changes in the components of the mold slag during casting, the molten steel throughput, that is, the number of charges, is increased unless the deterioration of the device such as the immersion nozzle 22 occurs. The casting time can be extended, and the performance of the cast can be improved, and the yield of the cast can be improved.

Herein, the change of the component slag of the mold slag is measured by changing the temperature of the mold 30. However, the mold slag may be collected during casting to analyze the component of the mold slag. Alternatively, when Al ₂ O ₃ is introduced into the mold slag, since the color of the mold slag is changed, the component change of the mold slag can be measured visually.

Hereinafter, a second embodiment of the present invention will be described.

FIG. 5 is a block diagram conceptually illustrating a method of injecting a molten mold flux into a mold when casting a slab by a casting method according to a second exemplary embodiment of the present invention.

In the second embodiment of the present invention, a method of casting different steel grades, for example, two steel grades, will be described.

For example, when casting a cast using high Al steel or high Mn steel, mold flux having different components is used. In this case, the mold flux used includes CaO, SiO ₂ , MnO, P ₂ O ₅ , Al ₂ O ₃ , MgO, TiO ₂ , K ₂ O, Na ₂ O, F, Fe ₂ O ₃ , There is a difference in content, and may further include other ingredients. Therefore, in the case of continuously casting such steel grades, different mold fluxes are injected when the steel grades are changed. In this case, a suitable mold flux must be prepared separately according to the steel grade, and if the production quantity of the steel grade to be cast is small, the molten mold flux remaining in the melting furnace is discarded and the new mold flux is melted to prepare the molten mold flux or different components during casting. The mold flux of the mixture is mixed and the transition to the mold 30 is generated.

Therefore, in the second embodiment of the present invention, the components of the molten mold flux may be adjusted and injected into the mold 30 according to the steel type used during casting.

Hereinafter, the mold flux applicable to all steel grades is called a main mold flux, and the additive used in the initial casting is a first additive, and the additive used when the steel grade is changed during casting is called a second additive. In addition, the additive used according to the result measured by the measuring unit 130 during casting is referred to as a third additive.

In the casting method according to the second embodiment of the present invention, a process of preparing a main mold flux, a first additive, a second additive, and a third additive, molds the first molten steel through the ladle 10 and the tundish 20 Injecting the first molten mold flux prepared by mixing the main mold flux and the first additive on the upper portion of the first molten steel injected into the mold 30, and casting the first molten steel. Upon completion, the process of injecting the second molten steel into the mold 30, and injecting the second molten mold flux prepared by using the main mold flux and the second additive on top of the second molten steel injected into the mold 30 Process may be included. In addition, in the process of casting the cast using the first molten steel and the second molten steel may include the process of measuring the casting state and the process of injecting a third additive according to the casting state.

Here, the casting process using the first molten steel and the casting process using the second molten steel may be continuously performed. The process of measuring the casting state and the process of injecting the third additive may be completed by the casting of the second molten steel. It can be repeatedly performed during the casting process by the determined process.

First, the process of preparing the main mold flux, the first additive, the second additive and the third additive, the main mold flux applicable to all steel grades, and the first additive for adjusting the components of the mold flux according to the steel grade And a second additive for adjusting the components of the mold slag during casting. The main mold flux may include CaO, SiO ₂ , MnO, P ₂ O ₅ , Al ₂ O ₃ , MgO, TiO ₂ , K ₂ O, Na ₂ O, F, Fe ₂ O ₃ , and the like. And a third additive _{NaF (S), Na 3 AlF} 6, CaF 2 (S), AlF 3 (s), SiO 2 (s), Li 2 O (s), LiF (s), CaO, MnO, P _{At least one of 2} O ₅ , MgO, Al ₂ O ₃ (s), TiO ₂ , Fe ₂ O ₃ , K ₂ O (s), Na ₂ O (s), C. In addition, the first and second additives are for controlling the components of the mold flux according to the steel grade, and may include at least one of the components of the main mold flux, and may include at least one of the components of the second additive. . That is, the first additive and the second additive are CaO, SiO ₂ , MnO, P ₂ O ₅ , Al ₂ O ₃ , MgO, TiO ₂ , K ₂ O, Na ₂ O, F, Fe ₂ O ₃ , NaF (S ), Na ₃ AlF ₆ , CaF ₂ (S), AlF ₃ (s), SiO ₂ (s), Li ₂ O (s), LiF (s), CaO, MnO, P ₂ O ₅ , MgO, Al ₂ At least one of O ₃ (s), TiO ₂ , Fe ₂ O ₃ , K ₂ O (s), Na ₂ O (s), C. In addition, the first additive and the second additive may be the same component.

The main mold flux thus prepared may be stored in the first reservoir 112a of the first raw material storage portion, and the first additive, the second additive, and the third additive are stored in the second reservoir 114a of the second raw material storage portion. Can be. In this case, the second reservoir 114a may be provided in plural to store components of the first additive, the second additive, and the third additive.

Then, when casting is started, the first molten steel is injected into the mold 30 and the first molten mold flux manufactured by mixing the main mold flux and the first additive on the first molten steel.

When the casting using the first molten steel is completed, the second molten steel is injected into the mold 30, and the second molten mold flux prepared by mixing the main mold flux and the second additive on the second molten steel is injected.

For example, when the first molten steel is a high manganese steel and the second molten steel is a high manganese-high aluminum steel, the first molten mold flux and the second molten mold flux have a difference in content of Al ₂ O ₃ . That is, the first molten mold flux contains less Al ₂ O ₃ than the second molten mold flux.

Therefore, when the first molten steel is injected into the initial casting mold 30, a small amount of Al ₂ O ₃ , such as less than 1%, is added to the main mold flux and the first additive, and casting using the first molten steel is completed. ) When the second molten steel is injected, 1 to 3% of Al ₂ O ₃ may be added as the main mold flux and the second additive. In this case, the second additive may be added by gradually increasing the second molten mold flux to have suitable properties for the second molten steel. This is because when the physical properties, such as viscosity or basicity, of the second molten mold flux are drastically changed, it may not be smoothly flowed between the mold and the solidification cell, and thus, cast rupture may occur.

In the above example, the first additive and the second additive are made of the same component and the example of increasing the input amount, but the input amount of the first additive and the second additive gradually gradually depending on the type of molten steel injected into the mold 30 It may be reduced, and of course, the components of the first and second additives may be different from each other. In addition, the method of performing casting using two kinds of molten steel has been described, but casting may be performed using two or more kinds of molten steel.

In addition, during casting using two kinds of steel, that is, the first molten steel and the second molten steel, the casting state may be measured as in the above-described embodiment, and the components of the mold slag may be adjusted using the second additive according to the measurement result. to be.

Hereinafter, an experimental example of casting the cast steel by the casting method according to the present invention. This experimental example looks at the change in the mold temperature according to the addition of additives during the casting of cast steel using a single steel grade.

Figure 6 is a graph showing the experimental results of the addition of additives when casting the cast in the casting method according to an embodiment of the present invention, showing the temperature change of the mold according to the addition of additives during casting.

A plurality of temperature measuring instruments were installed in the mold 30, and the temperature of the mold 30 was measured during casting. The temperature measuring device has a plurality of points along the length direction of the mold 30, for example, the casting direction of the cast steel, in the width direction center of the mold 30, for example, the width direction of the cast steel, specifically 300, 400 from the top of the mold 30. , 500 and 600 mm points.

Then, molten steel was injected into the mold 30 and the first molten mold flux in which the main mold flux was dissolved was injected into the upper portion of the molten steel injected into the mold 30.

Looking at Figure 6, the casting initial (section A) it can be seen that the temperature of the mold 30 changes within a certain range. However, in the middle of casting (Section B), it can be seen that the temperature of the mold 30 changes abruptly and fluctuates irregularly. The temperature of the mold 30 was observed for a certain time but did not return to the same pattern as the initial casting (Section A).

Accordingly, the second molten mold flux, in which the main mold flux and the additive were mixed and melted, was introduced into the mold 30. At this time, fluorine (F) was added as an additive.

When the second molten mold flux is injected into the mold 30, the temperature of the mold 30 gradually changes stably and changes within a certain range.

Such a phenomenon may occur when the mold slag is changed during the casting through the reaction with impurities in the molten steel. Therefore, the casting can be performed smoothly by adjusting the components of the mold slag by adding an additive during casting, thereby suppressing or preventing the deterioration of the cast steel.

In the above, the method and apparatus for casting the cast steel have been described, but the present invention is not limited thereto, and may be applied to various operations such as refining processes using liquid dephosphorization material.

As described above, in the detailed description of the present invention, specific embodiments have been described. However, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Melt injection apparatus according to the present invention, casting equipment and casting method using the same, can be applied to the continuous casting process for casting the cast steel can improve the quality and productivity of the cast steel.

Claims (24)

1. A raw material supply unit for supplying different kinds of raw materials;

   A mixing unit for preparing a mixture by mixing different kinds of raw materials supplied from the raw material supply unit;

   A melting part connected to the mixing part to melt a mixture supplied from the mixing part to generate a melt, and a discharge port through which the melt is discharged is provided; And

   A controller for controlling the components of the mixture by controlling operations of the raw material supply unit, the mixing unit, and the melting unit;

   Melt injection apparatus comprising a.
2. The method according to claim 1,

   The raw material supply unit comprises a first raw material supply unit for supplying a first raw material and a second raw material supply unit for supplying a plurality of second raw materials having different components individually.
3. The method according to claim 2,

   The first raw material supply unit,

   A first storage unit for storing the first raw material;

   A first conveying pipe connecting the first reservoir and the mixing part; And

   A first cutting machine provided in at least one of the first reservoir and the first transfer pipe to adjust the discharge of the first raw material;

   Melt injection apparatus comprising a.
4. The method according to claim 3,

   The second raw material supply unit,

   A plurality of second reservoirs respectively storing the plurality of second raw materials;

   A second transfer pipe connecting the plurality of second reservoirs and the mixing unit, respectively; And

   A second cutting machine provided in at least one of the second storage unit and the second transfer pipe to adjust the discharge amount of the second raw material;

   Melt injection apparatus comprising a.
5. The method according to claim 4,

   The mixing unit and the mixing vessel in communication with the first supply pipe and the second supply pipe;

   An agitator provided in the mixing vessel to mix the first raw material and the second raw material; And

   A third transfer pipe transferring the mixture of the first raw material and the second raw material to a melting part;

   Melt injection apparatus comprising a.
6. The method according to claim 4,

   The mixing unit includes a mixing vessel in communication with the first supply pipe and the second supply pipe,

   The mixing vessel is rotatable melt injection device.
7. The method according to claim 6,

   The melting part,

   A melting furnace having a melting space in which the first raw material and the second raw material are accommodated and dissolved therein;

   And a heat source supply unit provided at one side of the melting furnace to supply a heat source to the melting space.
8. The method according to claim 7,

   The heat source supply unit melt injection apparatus using a plasma as a heat source.
9. The method according to claim 8,

   The control unit is a melt injection device for controlling the input of the second raw material in accordance with the input signal.
10. As a casting facility,

    A mold for receiving the molten steel and initially solidifying the molten steel;

    A melt injection device for injecting a molten mold flux into the mold;

    A measuring unit measuring at least one of a temperature of the mold and a component of a molten mold flux injected into the mold; And

    And a control unit for controlling an operation of the melt injection apparatus to change a component of a molten mold flux injected into the mold according to a measurement result of the measurement unit.
11. The method according to claim 10,

    The melt injection device includes a first raw material supply unit for supplying the main mold flux;

    A second raw material supplier for supplying an additive;

    A mixing unit for mixing the main mold flux supplied from the first raw material supply unit and the second raw material supply unit and the additive to prepare a mixture; And

    A melter which melts the mixture supplied from the mixer to produce a molten mold flux and injects the molten mold flux into the mold;

    Casting equipment comprising a.
12. The method according to claim 11,

    The second raw material supply unit stores a plurality of additives individually,

    Casting facility for selectively supplying the plurality of additives to the mixing unit.
13. The method according to claim 12,

    The measuring unit comprises a temperature measuring device for measuring the temperature of the mold.
14. The method according to claim 12,

    The measuring unit includes a probe for collecting the molten mold flux injected into the mold, and a casting equipment including an analyzer for analyzing the components of the molten mold flux collected by the probe.
15. The method according to claim 13 or 14,

    The control unit determines whether or not to add the additive using the results measured by the measuring unit, and controls the second raw material supply unit in accordance with the results to adjust the type and amount of additives.
16. As the casting method,

    Preparing a main mold flux;

    Injecting molten steel into the mold;

    Melting the main mold flux to produce a molten mold flux and injecting the molten mold flux into the molten steel;

    Casting of cast steel; And

    Determining whether or not to add an additive according to the casting state in the casting of the cast steel.
17. The method according to claim 16,

    In the process of preparing the main mold flux,

    Casting method for providing the additive.
18. The method according to claim 17,

    In the process of manufacturing the molten mold flux by melting the main mold flux,

    A casting method of melting the main mold flux and the additive together.
19. The method according to claim 18,

    In the casting of the cast steel, the temperature of the mold is measured as the casting state,

    Casting method for determining whether to add the additive in accordance with the measured temperature value of the mold.
20. The method according to claim 18,

    Analyzing the components of the molten mold flux injected into the mold as the casting state in the process of casting the cast steel,

    Casting method for determining whether to add the additive according to the components of the molten mold flux analyzed.
21. The method according to claim 19 or 20,

    When the addition of the additive is determined, the main mold flux and the additive is mixed and melted to inject the molten mold flux, the component of which is changed into the mold.
22. The method according to claim 21,

    And casting the molten mold flux, the component of which is changed, by mixing the main mold flux and the additive and then melting the molten steel injected into the mold during the casting of the cast steel.
23. The method according to claim 22,

    When mixing the main mold flux and the additive, a casting method for adding an additive of different components according to the type of molten steel.
24. The method according to claim 22,

    When mixing the main mold flux and the additive, the casting method for changing the dosage of the additive having the same component according to the type of the molten steel.

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