KR101790001B1 - Melt supply equipment, casting apparatus and casting method - Google Patents

Abstract

The present invention relates to a melt injection apparatus, a casting facility using the same, and a casting method, and more particularly, to a process for preparing a main mold flux; A process of injecting molten steel into the mold; Melting the main mold flux to produce a molten mold flux, and injecting the molten mold flux onto the molten steel; The process of casting a casting; And determining whether to add the additive according to the casting state during the casting of the cast steel, thereby improving the quality and productivity of the cast steel.

Description

Technical Field [0001] The present invention relates to a melt injection apparatus, a casting apparatus and a casting method using the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melt injection apparatus, a casting apparatus and a casting method using the same, and more particularly, to a melt injection apparatus, a casting apparatus and a casting method using the apparatus.

A melt injection device, such as a molten mold flux injection device, used in the casting process of casting molds is a device for melting a mold flux and supplying it to a mold. A typical molten mold flux injection facility includes a hopper for storing a mold flux, a melting furnace for melting and supplying the mold flux from the hopper, and a torch for melting the mold flux by spraying a flame into the melting furnace at one side of the melting furnace . At this time, a discharge port through which the melted mold flux is discharged may be formed in the melting furnace.

When the mold flux is melted and supplied to the mold as described above, it is possible to suppress the temperature drop of the molten steel in the mold, and at the same time, it is possible to improve the lubrication performance and reduce the defects of the cast steel.

However, in the case of casting a casting mold by melting the mold flux produced in a melting furnace so as to have a characteristic component for each steel type, the component of the mold flux changes due to the reaction between the impurity contained in the casting and the mold flux. For example, when casting is performed using molten steel containing a large amount of Al, Al 2 O 3 is picked up in the mold flux, and the viscosity of the mold flux is increased. Therefore, since the mold flux does not flow smoothly between the mold and the cast (solidification cell), the heat transfer between the molten steel and the mold becomes uneven, and the lubricating ability deteriorates, causing cracking of the solidification cell or cracking on the surface of the cast steel. .

Such a change in physical properties of the mold flux makes it difficult to perform multi-piece performance over a charge of a single steel grade.

On the other hand, when playing various kinds of steel in a multi-piece manner, it is necessary to use a mold flux suitable for each steel type change. Therefore, when the steel grade is changed, the mold flux must be injected into the mold so as to have suitable properties. However, when the mold flux according to the steel type is supplied, it is preferable that the mold fluxes having different physical properties are not mixed. However, the mold fluxes having different physical properties due to the process characteristics are intermixed with each other. In such a transition, the mold flux does not flow smoothly between the mold and the coagulation cell, and thus the coagulation cell breaks up often occurs.

KR2014-70037A KR 2013-70667A

The present invention provides a melt injection apparatus capable of improving the casting efficiency, a casting facility using the same, and a casting method.

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

The apparatus for injecting molten metal according to the embodiment of the present invention comprises: a raw material supply unit for supplying different kinds of raw materials; A mixing unit for mixing the different raw materials supplied from the raw material supply unit to produce a mixture; A melted portion connected to the mixing portion to melt the mixture supplied from the mixing portion to produce a melt and having a discharge port through which the melt is discharged; And a controller for controlling the operation of the raw material supplying unit, the mixing unit, and the melting unit to adjust the composition of the mixture.

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

The first raw material supply unit includes a first reservoir for storing the first raw material; A first transfer pipe connecting the first reservoir and the mixing unit; And a first absorber provided in at least one of the first reservoir and the first transfer pipe to adjust the discharge amount of the first raw material.

Wherein the second raw material supply unit comprises: a plurality of second reservoirs for respectively storing the plurality of second raw materials; A second transfer pipe connecting the plurality of second reservoirs to the mixing section; And a second absorber disposed on at least one of the second reservoir and the second conveyance pipe to regulate the discharge amount of the second raw material.

Wherein the mixing unit includes: a mixing vessel communicating with the first transfer pipe and the second transfer pipe; An agitator provided in the mixing vessel for mixing the first raw material and the second raw material; And a third transfer pipe for transferring the mixture of the first raw material and the second raw material to the molten portion.

The mixing section may include a mixing container communicating with the first transfer pipe and the second transfer pipe, and the mixing container may be rotatable.

Wherein the melting unit comprises: a melting furnace having a melting space in which the first raw material and the second raw material are 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 a plasma as a heat source.

The control unit may control whether the second raw material is input according to an input signal.

A casting equipment according to an embodiment of the present invention includes: a mold for receiving molten steel and performing initial solidification; A melt injection device for injecting the molten mold flux into the mold; At least one of a temperature of the mold and a component of the molten mold flux to be injected into the mold; And a control unit for controlling the operation of the melt injection apparatus so as to change a component of the molten mold flux injected into the mold according to a measurement result of the measurement unit.

The melt injection device includes a first raw material supply unit for supplying a main mold flux; A second raw material supply unit 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 with the additive to produce a mixture; And a melting unit for melting the mixture supplied from the mixing unit to produce a molten mold flux, and injecting the molten mold flux into the mold.

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

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

The measuring 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 control unit may determine whether to add the additive by using the measurement result of the measuring unit, and may control the type and amount of the additive by controlling the second raw material supply unit according to the result.

As a casting method according to an embodiment of the present invention, a process of preparing a main mold flux; A process of injecting molten steel into the mold; Melting the main mold flux to produce a molten mold flux, and injecting the molten mold flux onto the molten steel; The process of casting a casting; And determining whether to add the additive according to the casting state during the casting of the cast steel.

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

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

The temperature of the mold may be measured as the casting state in the process of casting the cast steel, and the presence or absence of the additive may be determined according to the measured temperature value of the mold.

It is possible to analyze the components of the molten mold flux injected into the mold as the casting state in the process of casting the cast steel and determine whether the additive is injected or not according to the analyzed components of the molten mold flux.

When the addition of the additive is determined, the main mold flux and the additive are mixed and melted to inject the molten mold flux whose composition has been changed into the mold.

When the type of molten steel injected into the mold is changed in the course of casting the cast slab, the main mold flux and the additive may be mixed and melted to inject the molten mold flux having a changed composition into the mold.

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

When the main mold flux and the additive are mixed, the amount of the additive having the same component can be changed depending on the type of the molten steel.

According to the embodiments of the present invention, the casting efficiency and the quality of the cast steel can be improved in response to a change in the component of the molded slag during casting. That is, an additive for controlling the components of the mold slag during casting can be added to cope with changes in the components of the mold slag in real time. Therefore, it is possible to prevent the cracks on the surface of the cast steel or the collapse of the solidification cell due to a change in the composition of the mold slag, thereby improving the quality of the cast steel. In addition, since a single steel grade can be used as a steel grade, the productivity can be improved.

In addition, when a variety of steel pieces are continuously played, the molten mold flux suitable for the steel grade can be rapidly produced and supplied, thereby improving the casting efficiency. Therefore, it is possible to reduce the mixing time of the molten mold flux having different physical properties, and to suppress or prevent occurrence of the blowing phenomenon of the cast steel.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a casting installation according to an embodiment of the present invention.
Fig. 2 is a view showing the configuration of a main part of the casting equipment shown in Fig. 1; Fig.
3 is a block diagram showing the configuration of the casting equipment shown in Fig.
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 a molten mold flux into a mold in casting a cast steel according to a casting method according to a second embodiment of the present invention.
FIG. 6 is a graph showing experimental results according to whether or not an additive is input when a cast steel is cast according to an embodiment of the present invention. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

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

1, a casting apparatus according to an embodiment of the present invention includes a ladle 10 containing molten steel refined in a steelmaking process, and a casting nozzle (not shown) connected to the ladle 10 to supply molten steel A mold 30 for receiving molten steel through the tundish 20 connected to the tundish 20 and performing initial solidification in a predetermined shape, And a cooling line 40 provided at a lower portion of the mold 30 and in which a plurality of segments are successively arranged so as to perform a series of molding operations while cooling the uncrosslinked slab 1 drawn from the mold 30 .

2 and 3, the casting apparatus includes a melt injection device 100 for melting and supplying a mold flux to a molten steel bath surface supplied to the mold 30, And a control unit 140 for controlling the operation of the melt injection apparatus 100 according to the measurement result of the measurement unit 130. [

The melt injection apparatus 100 can melt the solid mold flux and supply the liquid mold flux, that is, the molten mold 30, to the mold 30. Conventionally, the mold 30, which is provided so as to have a specific component according to the type of steel, is melted in real time by a heating means such as a plasma torch and supplied to the mold 30. However, even if the molten mold 30 supplied into the mold 30 during casting reacts with the impurities in the molten steel to change the constituents thereof, the mold 30 is continuously supplied in the melt injection apparatus, It is impossible to cope with the change of the component in real time.

In addition, in the case of playing the brassiere, the mold 30 having different components is provided according to the type of steel, so it takes time to change to the mold 30 having the component suitable for the steel grade, The mold 30 of the component is inevitably mixed and the mold 30 can not be injected smoothly between the mold 30 and the coagulation cell to cause problems such as collapse of the coagulation cell.

In order to solve the problems of the above-described apparatus for injecting molten metal in the present invention, the apparatus for injecting molten metal 100 is constructed so that the components of the molten mold 30 supplied to the mold 30 can be changed in real time. Hereinafter, the mold flux is referred to as a mold flux before being supplied to the melting furnace 112, and the molten mold flux is referred to as a molten mold flux after the solid phase mold is melted in the melting furnace 112. Further, after the molten mold flux is injected into the mold 30, it is referred to as mold slag.

The apparatus 100 for injecting molten metal according to an embodiment of the present invention includes a raw material supply unit 110 for supplying a solid mold flux and a molten mold flux for dissolving and melting a solid mold flux, And a control unit 140 for controlling the operation of the raw material supply unit 110 and the fused portion 120. The control unit 140 controls the operation of the fused portion 120,

The raw material supplying unit 110 includes a first raw material supplying unit 112 for supplying a first raw material, a second raw material supplying unit 114 for supplying a second raw material, a first raw material supplying unit 112 and a second raw material supplying unit 114 A mixing unit 116 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, . ≪ / RTI > The raw material supply part 110 may supply the mixture of the first raw material and the second raw material to the melted part 120 through the mixing part 116, And a raw material feeder 118 capable of uniformly feeding the raw material or a mixture of the first raw material and the second raw material into the melting portion 120.

The first raw material supply unit 112 includes a first reservoir 112a for storing a first raw material such as a main mold flux and a first transfer pipe 112b for communicating the first reservoir 112a and the mixing unit 116 ).

The first reservoir 112a stores the first raw material in a solid state, for example, the main mold flux. A first absorber 112c for discharging the main mold flux to the first transfer pipe 112b by a predetermined amount or uniformly is provided in the first discharge pipe 112b or the portion where the main mold flux is discharged from the first reservoir 112a, May be provided. The first absorber 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, And may be a valve that opens or closes the flow path on the connection portion of the first transfer pipe 112b or the flow path inside the first transfer pipe 112b.

The second raw material supply unit 114 includes a second reservoir 114a for storing a second raw material such as an additive and a second transfer pipe 114b for communicating the second reservoir 114a and the mixing unit 116 . At this time, a plurality of second reservoirs 114a may be provided to store various kinds of additives independently. A second absorber 114c for discharging the additive to the mixer 116 by a predetermined amount or uniformly is provided in the portion of the second reservoir 114a where the additive is discharged or the second transfer pipe 114b And the second shredder 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, And the second transfer pipe 114b, or may be a valve that opens and closes the flow path inside the second transfer pipe 114b.

With this configuration, the second raw material supply portion 114 can selectively supply at least any one of the plurality of additives.

The mixing portion 116 can supply the molten portion 120 with the mold flux uniformly mixed with the main mold flux discharged from the first raw material supply portion 112 and the second raw material supply portion 114 and the additive. The mixing part 116 may supply only the first raw material supplied from the first raw material supplying part 112 to the melting part 120. The mixing section 116 includes a mixing vessel 116a for receiving the main mold flux and the additive supplied from the first raw material supply section 112 and the second raw material supply section 114 and a main mold flux (Not shown) for mixing the additive uniformly 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 molten part 120. [

The mixing vessel 116a can receive the main mold flux and additive in the solid state discharged from the first raw material supply unit 112 and the second raw material supply unit 114. [ A third outlet for discharging a mixture of the first and second raw materials in a predetermined amount or in a uniform manner to the third conveying pipe 116b at a portion where the mixture of the main mold flux and the additive is discharged from the mixing vessel 116a 116c. At this time, the third shredder 116c may be a screw installed in the mixing vessel 116a or the third transfer pipe 116b and operated by driving the motor, or may be a screw operated in the mixing vessel 116a and the third transfer pipe 116b , Or may be a valve that opens and closes the flow path inside the third transfer pipe 116b.

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

Although the mixing section 116 is described as including the mixing vessel 116a and the stirrer, the mixing vessel 116a may be configured to be rotatable so that the main mold flux and the additives may be uniformly mixed without an agitator . The mixing portion 116 is not limited to this, and may be formed in various shapes capable of uniformly mixing the main mold flux and the additive.

The mixing portion 116 may also include a heater 116d for preheating the mixture of the main mold flux or the main mold flux and the additive. The heater 116d may be provided in an agitator or a mixing vessel. The mixture of the main mold flux or 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 includes a third reservoir 118a communicating with the third conveying pipe 116b of the mixing unit 116 and a third reservoir 118b connecting the third reservoir 118a and the melted portion 120, A fourth transfer pipe 118b for supplying the first raw material or a mixture of the first and second raw materials through the third reservoir 118a or the fourth transfer pipe 118b, A fourth cutter 118c for discharging a mixture of the first raw material and the second raw material to the melted portion 120 by a predetermined amount or uniformly may be provided. The fourth cutter 118c is also provided in the third reservoir 118a or the fourth conveying line 118b as in the first to third cutters 112c, 114c, and 116c described above, It may be a working screw feeder or valve.

The raw material feeder 118 may also include a main mold flux supplied from the mixing section 116 or a heater 118d for preheating a mixture of the main mold flux and the additive. The heater 118d may be provided in the third reservoir 118a or the fourth transfer pipe 118b and may supply the main mold flux or the mixture of the main mold flux and the additive to the melted portion 120 by heating to a predetermined temperature . Therefore, melting of the mixture of the main mold flux or the main mold flux and the additive is promoted, so that it is possible to respond more quickly to changes in the component of the mold slag.

The melted portion 120 generates and temporarily stores the molten mold flux by heating and melting the mold flux supplied from the mixing portion 116, that is, the mixture of the main mold flux and the additive, and discharges the molten mold flux, 30). The melted portion 120 may include a melting furnace 112 that receives the mixture supplied from the mixing portion 116 and a heat source supply portion 128 that supplies a heat source into the melting furnace 112.

The melting furnace 112 is formed with a melting space in which the main mold flux and the additive are injected and dissolved therein. On one side, a discharge port 126 for injecting the molten mold flux into the mold 30 may be formed. The melting furnace 112 is formed in a substantially "V" -shaped shape whose center portion is bent downward, and can be tiltably provided. The melting furnace 112 is provided with an injection port 124 for injecting the mold flux discharged from the mixing section 116 into the melting space at an upper portion and a discharge port 126 for injecting the molten mold flux generated in the melting space into the mold 30 ). A 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 mold flux in the melting space is melted to generate and temporarily store the molten mold flux and the molten mold flux is discharged through the discharge port 126 on the other side to inject the molten mold flux into the mold 30 . This is possible because the melting furnace 112 is configured to be tiltable, and it is possible to adjust the discharge amount of the molten mold flux temporarily stored in the melting space according to the degree of tilting of the melting furnace 112.

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

The melting furnace 112 constituting the melted portion 120 may be formed in various other shapes, and the molten mold flux may be discharged by various methods. Such a melting portion 120 is a known technology, and a more detailed description thereof will be omitted.

Through the above-described structure, the melt injection apparatus 100 can control the components of the mold flux in real time and dissolve them, and then inject the melt into the mold 30.

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 components of the mold flux injected into the mold 30 .

When the temperature measuring unit is used as the measuring unit 130, the temperature measuring unit can be installed in the mold 30 to measure the temperature change of the mold 30. [ For example, when a single steel piece is played in a multi-stage manner, Al ₂ O ₃ flows into the mold slag after a certain period of time after casting, thereby increasing the viscosity of the mold slag. The mold slag is unevenly introduced between the mold 30 and the solidification cell, and the lubrication action is not properly performed. Due to this influence, heat transfer from the solidification cell to the mold 30 is not performed uniformly, resulting in a variation in the temperature value measured by the temperature measuring device. Therefore, the component of the molten mold flux to be injected into the mold 30 is changed according to the temperature value measured by the temperature measuring device, and is injected into the mold 30, thereby improving the casting performance.

When a probe is used as the measuring unit 130, a part of the mold slag in the mold 30 is sampled and the components of the mold slag collected through the probe are analyzed to determine the molten mold flux injected into the mold 30, The components of the slag can be compared and analyzed. Accordingly, the casting performance can be improved by changing the component of the molten mold flux to be injected into the mold 30 in response to the change in the composition of the mold slag during casting and injecting the molten mold flux into the mold 30.

The contents of mixing the additive in the mold flux through 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 supplying unit according to the measurement result to control the supply amount of the main mold flux and the additive to thereby control the composition of the molten mold flux Can be controlled. The controller 140 may control the operation of the melter 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 for casting a cast steel using a single steel piece and a second embodiment for casting the cast steel using the cast steel.

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

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

The casting method according to the first embodiment of the present invention includes a step of injecting molten steel having passed through the main mold flux and additive (S110), the ladle 10 and the tundish 20 into the mold 30 (S140) of injecting molten mold flux into the upper part of the molten steel injected into the mold 30 (S130), measuring the casting state (S140), and determining whether the additive is injected (S150) (S160). ≪ / RTI > The process of injecting molten steel into the mold 30 and injecting the molten mold flux may be performed continuously during the casting process. The process of measuring the casting state and the process of injecting the additive can be repeatedly performed during the casting process by determining the completion of casting (S170).

Hereinafter, the molten mold flux injected into the mold 30 at the beginning of casting is referred to as a first molten mold flux, and the molten mold flux injected into the mold 30 by mixing with the additive during casting is referred to as a second molten mold flux.

The main mold flux and additives are prepared by providing a solid main mold flux in the first reservoir 112a and an additive to be mixed with the main mold flux during casting in the second reservoir 114a. At this time, the molten mold flux, and the like _{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. The main mold flux may be made to have a composition suitable for molten steel used for casting. And 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 2 O ₅ , at least one of MgO, Al ₂ O ₃ (s), TiO ₂ , Fe ₂ O ₃ , K ₂ O (s), Na ₂ O (s) .

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

When the 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 prepared by melting the main mold flux stored in the first reservoir 112a in the melted portion 120 through the mixing vessel 116a of the mixing portion 116. [ The first molten mold flux injected at the beginning of the casting may be one prepared by melting only the main mold flux in the molten portion 120.

In this manner, the molten steel and the first molten mold flux can be injected into the mold 30 to cast the cast. The first molten mold flux injected into the mold 30, that is, the mold slag flows between the mold 30 and the solidifying cell (or molten steel) to control the heat transfer between the mold 30 and the solidifying cell, Smooth casting.

The initial mold slag retains its components when injected, but as the casting progresses, the impurities in the molten steel flow into the mold slag and the components of the mold slag change. 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, and the mold slag flows in the width direction and the longitudinal direction of the mold 30 in a non-uniform manner.

Due to this influence, the heat transfer between the mold 30 and the solidification cell is uneven, so that the solidification cell is not formed properly, and surface defects are formed on the casting after casting, or a casting phenomenon occurs.

The second molten mold flux prepared by mixing the main mold flux and the additive during the casting process is injected into the mold 30 to rapidly change the component of the mold slag, thereby uniformly introducing the mold slag into the mold and the coagulation cells So that the quality of the cast steel can be improved.

Whether or not the additive is injected can be determined according to the casting state, for example, the temperature change of the mold 30 or the component change of the mold slag.

It is possible to measure the temperature change of the mold 30 during casting, mix the additives in an appropriate amount with the mold flux according to the measured temperature change, melt it, and inject it into the mold 30 to quickly cope with changes in the components of the mold slag. Accordingly, the mold slag can be uniformly introduced into the mold 30 and the solidification cell, and the heat transfer characteristic and the lubrication performance similar to those at the beginning of the casting can be maintained until the casting is completed.

The temperature of the mold 30 is measured by providing a plurality of temperature measuring devices in the mold 30 in the longitudinal direction and the width direction of the mold 30 and measuring the temperature values in the longitudinal direction and / Can be measured. Then, the deviation of the temperature value measured by the temperature measuring device can be measured. If the measured temperature value falls within a deviation range of more than 0% to 5% from the initially measured temperature value, casting can proceed as it is. Or if the measured temperature value deviates from the stated deviation range, the addition of the additive may be determined.

As a result of the comparison, if the measured temperature value is within the deviation range, the mold slag is uniformly injected between the mold 30 and the solidification cell, and the component change of the mold slag is judged to be insignificant. The first molten mold flux is injected into the mold 30.

However, when the measured temperature value deviates from the deviation range, it is judged that the change of the component of the mold slag has occurred to a great extent, and the molten mold flux into which the additive is injected, that is, the second molten mold flux can be injected into the mold 30.

The selection of the additive to be fed into the mold 30 can be selected as follows.

In the early stage of casting, there is almost no change in the composition of the mold slag, so the temperature value measured by the temperature measuring device changes within a certain range. However, as the casting progresses, the impurities in the molten steel flow into the mold slag, causing a change in the components of the mold slag. For example, Al ₂ O ₃ may enter the molten steel, or the 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 flow uniformly between the mold 30 and the solidification cell, so that the heat transfer performance is lowered, and the temperature value measured by the temperature measuring device installed in the mold 30 changes. In such a case, the mold flux and the additive are mixed and melted and then injected into the mold 30, whereby the decrease of the casting efficiency due to the change in the component of the mold slag can be suppressed or prevented. 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 and the like can be used as an additive. When fluorine in the mold slag is volatilized, Na ₃ AlF ₆ , NaF May be used. Therefore, the viscosity of the molded slag in the mold 30 can be lowered to some extent, so that the mold slag can be uniformly injected between the mold 30 and the solidified cell. For example, when injecting molten mold slag at 1 kg / min, Na ₃ AlF ₆ can be added as an additive at 50 g / min. 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 mold slag injected into the mold 30 is increased by ~ 2.7 wt%, the viscosity of the mold slag is increased, and the mold slag can flow smoothly between the mold and the solidification cell. On the other hand, the content of Al ₂ O ₃ and Na ₂ O also increases somewhat in the range of more than 0 to 2% by weight. Al ₂ O ₃ and Na ₂ O contents are not significantly changed compared to the fluorine content, so they do not affect the casting.

It is needless to say that at least one of the various kinds of additives described above may be used as the additive.

The main mold flux and the additive are mixed through the control unit 140. The control unit 140 receives the measurement result of the measuring unit 130, for example, the temperature measuring device, The main mold flux and the additives stored in the first reservoir 112a and the second reservoir 114a are mixed with each other by controlling the operation of the first reservoir 112c and the second reservoir 114c of the second reservoir 114, And supplies it to the mixing vessel 116a of the mixing unit 116.

Then, the controller 140 operates the stirrer of the mixing unit 116 to uniformly mix the additive with the main mold flux supplied to the mixing vessel 116a. When the main mold flux and the additive are uniformly mixed, the controller 140 operates the third cutter 116c of the mixer 116 to mix the mixture of the main mold flux and the additive into the melting furnace 112 of the melter 120 Inject.

The mixture injected into the melting furnace 112 is dissolved by the heat, i.e., plasma, provided in the heat source supply portion 128 of the melting portion 120, and is made into the second molten mold flux. The second molten mold flux thus produced is injected into the mold 30 through the discharge port 126 formed in the melting furnace 112 by tilting of the melting furnace 112 and mixed with the mold slag. The viscosity of the molded slag in the mold 30 is lowered and can be uniformly introduced between the mold 30 and the solidified cell.

In this way, the temperature of the mold 30 is constantly monitored during the casting of the cast steel, and the quality of the cast steel can be improved in response to the temperature change of the mold 30 due to the component change of the mold slag. Component control of the mold slag during casting can be repeatedly performed a plurality of times in accordance with the measurement result by the measuring unit 130. Accordingly, since the components of the mold slag can be quickly controlled in response to changes in the components of the mold slag during casting, the throughput of the molten steel, that is, the number of charges is increased as long as the deterioration of the apparatus such as the immersion nozzle 22 does not occur The casting time can be prolonged, and the yield can be increased and the yield of the cast steel can be improved.

Here, it is described that the component change of the mold slag is measured through the temperature change of the mold 30, but it is also possible to analyze the component of the mold slag by collecting the mold slag during casting. Alternatively, since the color of the mold slag is changed when Al ₂ O ₃ flows into the mold slag, it is possible to measure the change in the component of the mold slag even with the naked eye.

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

5 is a block diagram conceptually showing a method of injecting a molten mold flux into a mold when casting a cast steel using the casting method according to the second embodiment of the present invention.

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

For example, when a cast steel is cast using a high-Al steel or a high-Mn steel, a mold flux having different components is used. The mold flux used herein includes CaO, SiO ₂ , MnO, P ₂ O ₅ , Al ₂ O ₃ , MgO, TiO ₂ , K ₂ O, Na ₂ O, F and Fe ₂ O ₃ , And there may be further included other components. Therefore, when continuously casting such bridges, different mold fluxes are injected when the steel types are changed. In this case, it is necessary to provide a suitable mold flux according to the type of steel. If the amount of the steel to be cast is small, the molten mold flux remaining in the melting furnace is discarded, the new mold flux is melted to prepare a molten mold flux, The mold flux is mixed and supplied to the mold 30.

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

Hereinafter, the mold flux applicable to all steel types is referred to as a main mold flux, the additive used at the beginning of casting is referred to as a first additive, and the additive used when a steel grade is changed during casting is referred to as a second additive. The additive used in accordance with the result of measurement by the measuring unit 130 during casting is referred to as a third additive.

The casting method according to the second embodiment of the present invention includes the steps of providing a main mold flux, a first additive, a second additive, and a third additive, a ladle 10, a first molten steel passing through the tundish 20, Injecting the first molten mold flux prepared by mixing the main mold flux and the first additive into the upper portion of the first molten steel injected into the mold 30, And injecting the second molten mold flux produced by using the main mold flux and the second additive into the upper portion of the molten molten steel injected into the mold 30 Process. The method may further include a step of measuring a casting state in a process of casting the casting using the first molten steel and the second molten steel, and a step of injecting the third additive depending on the casting state.

Here, the casting process using the first molten steel and the casting process using the second molten steel can be continuously performed. In the process of measuring the casting condition and the process of injecting the third additive, the completion of casting using the second molten steel And can be repeatedly performed during the casting process according to the determined process.

First, the main mold flux, the first additive, the second additive, and the third additive are prepared. The main mold flux applicable to all the steel types and the first additive for adjusting the composition of the mold flux according to the type of steel 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 the third additive is NaF (S), Na ₃ AlF ₆ , CaF ₂ (S), AlF ₃ (s), SiO ₂ (s), Li ₂ O ₂ O ₅ , MgO, Al ₂ O ₃ (s), TiO ₂ , Fe ₂ O ₃ , K ₂ O (s), Na ₂ O (s) The first additive and the second additive 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 for controlling the components of the mold flux according to the type of the steel . That is, the first additive and the second additive may be 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 , _{), 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) Further, 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 reservoir 112a and the first additive, the second additive and the third additive may be stored in the second reservoir 114a of the second reservoir 114b . At this time, the second reservoir 114a may be provided in plurality to store the components of the first additive, the second additive, and the third additive.

Then, when the casting is started, the first molten steel is injected into the mold 30, and the first molten mold flux prepared by mixing the main mold flux and the first additive is injected into the upper portion of 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 is injected into the upper portion of the molten molten steel.

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

Accordingly, when the first molten steel is injected into the casting mold 30, a small amount, for example, less than 1% of Al ₂ O ₃ is injected into the main mold flux and the first additive, the casting using the first molten steel is completed, ), 1 to 3% of Al ₂ O ₃ can be injected into the main mold flux and the second additive when the second molten steel is injected. At this time, the second additive may be introduced by a method of gradually increasing the second molten mold flux so as to have suitable physical properties for the second molten steel. This is because if the physical properties of the second molten mold flux, for example, the viscosity or the basicity, are suddenly changed, smooth flow may not be caused between the mold and the solidification cell, resulting in the occurrence of a flake failure.

In the above example, the first additive and the second additive are made of the same component and the amount of the additive is increased. However, depending on the type of molten steel injected into the mold 30, And it is needless to say that components of the first additive and the second additive may be different from each other. In addition, although a method of performing casting using two types of molten steel has been described, casting may be performed using two or more types of molten steel.

In addition, it is possible to measure the casting state during the casting using the second molten steel, that is, the first molten steel and the second molten steel, and to control the components of the mold slag by using the second additive, to be.

Hereinafter, an experimental example of casting a cast steel using the casting method according to the present invention will be described. In this experiment, mold temperature changes according to whether additive is injected or not during casting of cast steel using single steel.

FIG. 6 is a graph showing experimental results according to whether or not an additive is added when a cast steel is cast by a casting method according to an embodiment of the present invention. FIG. 6 shows a temperature change of the mold depending on whether additives are added during casting.

A plurality of temperature measuring devices were provided on the mold 30, and the temperature of the mold 30 was measured during casting. The temperature gauge can be measured at a plurality of points along the width direction of the mold 30, for example, in the width direction center of the casting 30 in the longitudinal direction of the mold 30, , 500 and 600 mm, respectively.

Then, molten steel was injected into the mold 30 and the first molten mold flux, in which the main mold flux was melted, was injected into the molten steel injected into the mold 30.

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

The second molten mold flux obtained by mixing and melting the main mold flux and the additive was introduced into the mold 30. At this time, fluorine (F) was added as an additive.

When the second molten mold flux was injected into the mold 30, the temperature of the mold 30 gradually changed and changed within a certain range.

This phenomenon can be caused by the change of the constituents of the molten steel through the reaction of the mold slag with the impurities in the molten steel during casting. Therefore, by adding the additive during casting to adjust the components of the mold slag, the casting can be performed smoothly, and the deterioration of the quality of the cast steel can be suppressed or prevented.

Although a method and an apparatus for casting a cast steel have been described above, the present invention is not limited thereto and can be applied to various operations such as a refining process using an aqueous liquid tallin material.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims and equivalents thereof.

10: Ladle 20: Tundish
22: immersion nozzle 30: mold
40: cooling line 100: melt injection device
110: raw material supply part 112: first raw material supply part
114: second raw material supply part 116: mixing part
118: raw material injector 120:
130: measuring unit 140:

Claims (24)

A first raw material supply section for supplying a first raw material and a second raw material supply section for separately supplying a plurality of second raw materials different from the first raw material so as to be able to supply different kinds of raw materials, A supply part;
A mixing portion including a mixing container for mixing the first raw material and the second raw material supplied from the first raw material supplying portion and the second raw material supplying portion to produce a mixture;
A melting unit for melting the mixture supplied from the mixing vessel to produce a melt and providing a discharge port through which the melt is discharged; And
A control unit for controlling the operation of the raw material supplying unit, the mixing unit and the melting unit to adjust the composition of the mixture;
. The method according to claim 1,
And a raw material feeder for feeding the mixture to the fused portion between the mixing portion and the fused portion,
Wherein the raw material feeder comprises a heater for preheating the mixture. The method according to claim 1,
Wherein the first raw material supply portion includes:
A first reservoir for storing the first raw material;
A first transfer pipe connecting the first reservoir and the mixing vessel; And
A first absorber provided in at least one of the first reservoir and the first transfer pipe to regulate the discharge amount of the first raw material;
. The method of claim 3,
Wherein the second raw material supply portion includes:
A plurality of second reservoirs for respectively storing the plurality of second raw materials;
And a second transfer pipe connecting the plurality of second reservoirs and the mixing vessel respectively. The method of claim 4,
Wherein the mixing unit includes an agitator provided in the mixing vessel and mixing the first raw material and the second raw material;
A third transfer pipe for transferring the mixture of the first raw material and the second raw material to the molten portion; And
A heater for preheating the mixture;
. The method of claim 4,
Wherein the mixing vessel is rotatable. The method of claim 6,
The molten-
A melting furnace having a melting space in which the first raw material and the second raw material are 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 method of claim 7,
Wherein the heat source supply unit uses plasma as a heat source. The method of claim 8,
Wherein the controller controls whether the second raw material is input according to an input signal. As casting equipment,
A mold for receiving molten steel and performing initial solidification;
A melt injection device for injecting the molten mold flux into the mold;
A measuring unit for measuring at least one of a temperature of the mold and a component of the molten mold flux to be injected into the mold; And
And a controller for controlling the operation of the melt injection device so as to change a component of the molten mold flux injected into the mold according to a measurement result of the measurement part,
The melt injection device includes a first raw material supply unit for supplying a main mold flux;
A second raw material supply unit for supplying an additive;
A mixing portion including a mixing container for mixing the main mold flux and the additive to prepare a mixture; And
And a melting section for melting the mixture supplied from the mixing section to produce a molten mold flux and injecting the molten mold flux into the mold. The method of claim 10,
Wherein the molten material injecting apparatus includes a material feeder for feeding the mixture to the melting unit between the mixing unit and the melting unit,
Wherein the raw material feeder comprises a heater for preheating the mixture. The method of claim 11,
Wherein the second raw material supply portion separately stores a plurality of additives,
And the plurality of additives are selectively supplied to the mixing section. The method of claim 12,
Wherein the measuring section includes a temperature measuring device for measuring a temperature of the mold. The method of claim 12,
Wherein the measuring unit includes 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 method according to claim 13 or 14,
Wherein the control unit determines whether to add the additive by using the measurement result of the measuring unit and controls the type of the additive and the amount of the additive by controlling the second raw material supply unit according to a result of the determination. As a casting method,
A process of preparing a main mold flux;
A process of injecting molten steel into the mold;
Melting the main mold flux to produce a molten mold flux, and injecting the molten mold flux onto the molten steel;
The process of casting a casting;
The temperature of the mold and the components of the molten mold flux injected into the mold are analyzed in the process of casting the cast steel and the addition of the additive is determined according to the measured temperature value of the mold or the analyzed components of the molten mold flux process;
Injecting the additive into the mold after mixing the main mold flux and the additive and then melting the molten mold flux to prepare a molten mold flux;
≪ / RTI > 18. The method of claim 16,
In the process of preparing the main mold flux,
Wherein the additive is provided. 18. The method of claim 17,
In the course of manufacturing the molten mold flux by melting the main mold flux,
Wherein the main mold flux and the additive are melted together. 19. The method of claim 18,
Wherein the main mold flux and the additive are mixed and melted to prepare a molten mold flux whose composition is changed, and the molten mold flux is injected into the mold,
And preheating a mixture of the main mold flux and the additive. delete delete The method of claim 19,
Wherein when the type of the molten steel injected into the mold is changed in the course of casting the cast steel, the molten mold flux having the changed component is injected into the mold after the main mold flux and the additive are mixed and melted. 23. The method of claim 22,
Wherein when the main mold flux and the additive are mixed, additives of different components are added depending on the type of the molten steel. 23. The method of claim 22,
Wherein the amount of the additive having the same component is changed according to the kind of the molten steel when the main mold flux and the additive are mixed.

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