KR101795471B1 - Apparatus of alloy steel and manufacturing method using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing an alloy steel, comprising: an alloy iron supply portion; a melting portion for melting alloyed iron supplied from the alloy iron supply portion to produce molten alloyed iron; a molten alloy iron reservoir provided at a lower portion of the melting portion to directly inject the molten iron supplied from the molten iron and having an inner space formed therein to store the molten iron; and a control portion for controlling operation of the alloy iron supply portion and the melting portion according to an amount of the molten alloy iron stored in the molten alloy iron reservoir. In a course of producing the alloy steel, dissolution and storage of the alloy iron are continuously performed to suppress or prevent a temperature drop of the alloy iron.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alloy steel manufacturing apparatus and an alloy steel manufacturing method using the same,

More particularly, the present invention relates to an apparatus for manufacturing an alloy steel capable of suppressing or preventing temperature drop and contamination of molten steel and molten alloy iron, and a method of manufacturing an alloy steel using the apparatus.

Generally, in the case of ordinary high manganese steel, manganese (Mn) is contained in an amount of 1 to 5 wt%, and in some stainless steels, manganese content is 10 wt% or less. In recent years, in the case of a high-strength solid steel for automobiles, a steel having a manganese content of 15 to 25 wt% has been produced.

Generally, when a high manganese steel is produced by a converter process, molten iron is refined in a converter to prepare a molten steel, and a solid manganese alloy iron is added to the molten steel to control the content of manganese component. At this time, the amount of manganese alloy iron added to the molten steel increases according to the required manganese content.

If the amount of manganese alloy iron added to the molten steel is increased, the temperature of the molten steel is lowered, which is accompanied by a process of raising the temperature of the molten steel in a subsequent process.

In order to solve such a problem, a method of dissolving manganese alloy iron and injecting it into molten steel having been subjected to refining has been used.

However, the dissolution of converter refining and manganese alloy iron is performed in different processes, and each process takes a different time, resulting in the failure to timely inject the manganese alloy iron dissolved in the refined molten steel, resulting in a waiting time do.

When the waiting time is elapsed for charging the manganese alloy iron dissolved in the molten steel, the dissolved manganese alloy iron is exposed to the atmosphere and the temperature is lowered. In addition, the manganese has a high vapor pressure and a high affinity with oxygen and nitrogen, causing a phenomenon of adsorption, requiring additional processes for removing nitrogen and nitrogen after the molten steel. Further, there is a problem that the rate of realization of effective metals in the manganese alloy iron is lowered due to oxidation of manganese.

KR 1048981B KR 1047912B

The present invention provides an alloy steel manufacturing apparatus capable of improving the cleanliness by shortening the waiting time of molten iron iron, and an alloy steel manufacturing method using the same.

The present invention provides an alloy steel manufacturing apparatus capable of omitting an additional process such as refining and thereby improving productivity, and an alloy steel manufacturing method using the same.

An alloy steel manufacturing apparatus according to an embodiment of the present invention includes an alloy iron supply unit; A melted portion for melting alloyed iron supplied from the alloyed iron supply portion to produce molten alloyed iron; A molten iron iron reservoir provided at a lower portion of the molten iron to directly inject the molten iron supplied from the molten iron and having an inner space formed therein for storing the molten iron; And a control unit for controlling the operation of the alloy iron supply unit and the melted part according to the amount of the molten alloy iron stored in the molten iron iron reservoir.

The alloy iron supply unit may include a raw material reservoir for storing the alloyed iron and an ejector for discharging the alloyed iron stored in the raw material storage unit to the melted portion.

Wherein the melting unit includes a melting furnace having a melting space in which the alloy iron is melted and formed with a discharge port formed at one side of the melting space for discharging the molten ferrous iron and a melting furnace for supplying a heat source to the melting space at the other side of the melting furnace And a heat source supply unit.

The melting furnace may be tiltable.

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

Wherein the reservoir includes a body having a top open and a storage space in which the molten iron is stored, and a cover configured to open and close an upper portion of the body, wherein the molten iron is injected into the storage space An opening communicating with the discharge port is formed in the cover, and a discharge port may be formed in the body to discharge the molten iron.

The reservoir may include a level meter for measuring the level of the molten alloy iron bath stored in the storage space.

The control unit may control the operation of the alloy iron supply unit and the melting unit according to the level of the melt surface of the molten alloy iron measured by the measuring device so as to control the amount of the molten alloy iron stored in the storage space.

The discharge port may be provided with an anemometer for measuring the flow rate of the molten ferrous iron discharged through the discharge port.

The control unit calculates the amount of the molten alloy iron stored in the storage space according to the flow rate of the molten alloy iron measured by the anemometer so as to control the amount of the molten iron alloy stored in the storage space, The operation of the alloy iron supply part and the molten part can be controlled.

The reservoir may include a heating unit for heating the molten ferrous iron stored in the storage space.

The reservoir may include a gas supply unit for supplying the atmosphere gas to the storage space so as to control the atmosphere of the storage space.

And ladles for receiving molten ferrous iron discharged to the discharge port.

A process for producing an alloy steel according to an embodiment of the present invention is a process for preparing molten steel; Melting iron alloy to prepare molten iron; Injecting the molten alloy iron into a molten alloy iron storage vessel and storing the molten alloy iron at a temperature higher than the melting point; And a step of mixing the molten steel with the molten alloy, and intermittently melting the molten alloy so that the molten alloy is maintained at a preset reference amount in the process of storing the molten alloy at a temperature equal to or higher than the melting point, Into the iron reservoir.

Measuring a quantity of the molten alloy iron stored in the molten iron iron reservoir in the storing step; Melting the ferroalloy when the measured amount of the molten iron is less than the reference amount; And injecting the molten alloy iron further prepared into the molten iron iron reservoir.

The reference amount may include more than one amount of molten iron ferrous alloyed with the molten steel.

After the mixing process, at least one refining process such as LF (ladle furnace) refining and vacuum refining may be performed.

The denitrification process may be performed during the refining process.

The ferroalloy may include manganese.

According to the embodiment of the present invention, it is possible to suppress or prevent the temperature drop of the ferroalloy by continuously dissolving and storing the ferroalloy in the process of producing the alloy steel. In addition, since the dissolution and storage of the alloy iron are carried out continuously, the contact between the molten alloy iron and the atmosphere can be minimized, thereby preventing contamination or oxidation of the molten alloy iron due to contact with the atmosphere.

Further, it is possible to shorten the waiting time of the molten alloy iron due to the time difference required for preparing the molten alloy steel and the molten steel in the production of the alloy steel, thereby reducing the temperature of the molten alloy iron and also suppressing the contamination of the molten alloy iron, have. Therefore, it is possible to prevent a load from occurring in the subsequent refining process or the like, and the whole process time can be shortened, thereby improving the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing an apparatus for manufacturing an alloy steel according to an embodiment of the present invention; FIG.
2 is a schematic view showing an apparatus for manufacturing an alloy steel according to a modified example of the present invention.
3 is a block diagram conceptually showing a method of manufacturing an alloy steel according to an embodiment of the present invention.
4 is a view showing a process of manufacturing an alloy steel according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know.

1 is a schematic view showing an apparatus for manufacturing an alloy steel according to an embodiment of the present invention.

Referring to FIG. 1, an apparatus for manufacturing an alloy steel according to an embodiment of the present invention includes an alloy iron supply unit 110, a melting unit 120 for melting iron alloy supplied from the alloy iron supply unit 110, A molten alloy iron reservoir 130 and a molten alloy iron reservoir 130 which are provided at a lower portion of the molten portion 120 and in which an inner space is formed to store the molten iron produced in the molten portion 120, And a control unit 140 for controlling the operation of the molten iron supply unit and the molten iron according to the amount of molten iron to be stored. The apparatus for producing an alloy steel according to the embodiment of the present invention may include a ladle 20 for receiving molten steel to be molten with molten iron.

The iron alloy feeder 110 may include a raw material reservoir 112 for storing iron alloy and an ejector 114 for discharging alloy iron stored in the raw material reservoir 112 to the molten iron 120.

The raw material reservoir 112 may be formed with a space in which alloy iron is stored, an upper portion formed with an opening to insert alloy iron, and an outlet formed with a lower portion to discharge alloy iron. At this time, the opening may be opened or closed by using a separate lid, but it is preferable to close the opening of the raw material reservoir 112 to minimize the contact of the alloy iron with the atmosphere.

The discharger 114 is connected to the outlet of the raw material reservoir 112 to uniformly discharge the ferrous alloy stored in the raw material reservoir 112 to the fused portion 120. The discharge unit 114 includes a discharge pipe 114a connected to the discharge port of the raw material reservoir 112 and a discharge member 114b provided in the discharge pipe 114a and constantly discharging the ferrous iron stored in the raw material reservoir 112 . At this time, the discharge member 114b may be a screw feeder rotatably installed in the discharge pipe 114a, or may be a valve that opens and closes the flow path inside the discharge pipe 114a. Here, when the screw feeder is used as the discharge member 114b, it may further include a driver 114c that rotates the screw feeder. And a driver to actuate the valve when the valve is used as the discharge member 114b.

The melted portion 120 includes a melting furnace 122 having a melting space in which alloy iron is dissolved therein and having a discharge port 126 formed at one side of the melting space for discharging the molten alloy iron, And a heat source supply unit 128 for supplying a heat source to the dissolution space on the other side.

The melting furnace 122 is formed in a substantially "V" -shaped shape whose center portion is bent downward, and can be tiltably provided. The melting furnace 122 is provided with an injection port 124 for injecting the ferroalloy discharged from the raw material reservoir 112 into the melting space at an upper portion thereof and an injection port 124 for injecting the molten alloy iron generated in the melting space into the molten iron- (Not shown). A heat source supply unit 128 may be connected to one side of the melting furnace 122 so as to supply a heat source to the melting space. A heat source is supplied from one side of the melting furnace 122, and the ferroalloy is melted by a heat source to produce molten ferroalloy. The molten alloy iron thus produced is temporarily stored in the melting space. When the melting furnace 122 is tilted, the molten alloy iron may be discharged through the discharge port 126 on the other side to be injected into the molten iron iron reservoir 130. At this time, the degree of tilting of the melting furnace 122 may be adjusted to control the amount of molten iron to be discharged.

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 122. [ 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 generated plasma and plasma heat can be used as a heat source for dissolving alloy iron supplied to the dissolution space through the injection port 124, that is, solid alloy iron.

The melting furnace 122 may be formed in various other shapes, and the molten mold flux may also be discharged by various methods.

The molten alloy iron reservoir 130 includes a body 132 having a top opened and a storage space in which molten iron is stored and a cover 134 provided to open and close an upper portion of the body 132 can do.

The body 132 may include a shell 132a forming an external shape and a refractory 132b formed inside the shell 132a. At this time, a heat insulating material (not shown) may be provided between the outer shell 132a and the refractory 132b or outside the outer shell 132a. With such a configuration, the temperature of the molten iron contained in the body 132 can be prevented from being lowered, so that the molten iron can maintain the temperature of the molten alloy in the body 132 at a predetermined temperature, for example, a temperature higher than the melting point.

Further, though not shown, the body 132 may be disposed inside a separate housing to more effectively suppress the temperature drop of the molten iron alloy.

The body 132 may have an outlet 138 for discharging the molten iron. The discharge port 138 may be provided at any position on the side wall or the bottom of the body 132 as long as it can discharge the molten iron alloy for the purpose of the molten iron. At this time, the discharge port 138 may be formed at a position higher than the bath surface level of the molten iron alloy received in the body 132. This is because when the molten iron is discharged for melting with molten steel, the molten iron iron reservoir 130 is tilted in the direction in which the discharge port 138 is formed and discharged. The discharge port 138 may be provided with a first stop 137a for opening and closing the discharge port 138. The first stopper 137a prevents outside air from flowing into the body 132 through the outlet 138 and prevents the molten iron iron from flowing out through the outlet 138. [

The cover 134 may be provided to open and close the opening of the body 132 on the upper portion of the body 132. The cover 134 may be installed to prevent the molten iron contained in the body 132 from being exposed to the outside air and to suppress the temperature drop of the molten iron. The cover 134 may be formed with an opening 136 into which the molten iron supplied from the molten portion 120 is injected. The cover 134 may be provided with a second stopper 137b for opening and closing the opening 136. [ The second stop 137b may open the opening 136 when the molten iron is injected into the body and may otherwise block the interior space and the exterior of the body 132 by closing the opening 136. [

With such a configuration, the molten iron iron reservoir 130 can maintain the molten alloy iron at a predetermined temperature, for example, a temperature higher than the melting point, and minimize contact with the atmosphere.

In addition, the molten iron iron reservoir 130 may include a gas supply unit (not shown) for supplying the atmospheric gas to the inside of the body 132 so as to control the inside of the body 132. The gas supply unit may supply an inert gas such as argon or the like to the interior of the body 132. Through this, air that may be present inside the body 132 is discharged to the outside of the body 132 to prevent the fused alloy iron from being contaminated with air, for example, nitrogen or oxygen contained in air. In addition, an exhaust port (not shown) may be provided on the body 132 to maintain the internal pressure of the body 132 at a predetermined positive pressure. The vent may be opened if the pressure inside the body 132 exceeds a certain pressure.

The molten alloy iron reservoir 130 may be provided with a heating unit (not shown) for heating the molten iron. The heating unit may be configured in various forms such as an induction coil and an electrode.

The molten alloy iron reservoir 130 may be provided with a level meter 139 for measuring the level of the molten alloy iron contained in the body 132. The level meter 139 may be provided on the body 132 or on the cover 134. For example, when the level meter 139 is provided on the body 132, the level of the melt surface of the molten iron contained in the body 132 can be measured through a temperature measuring device such as a thermocouple. Or the level meter 139 is provided on the cover 134, the level of the melt surface of the molten iron contained in the body 132 can be measured using a sensor such as an eddy current sensor. The level meter 139 may measure the level of the molten alloy iron contained in the body 132 and transmit the measurement result to the controller 140.

The control unit 140 may control the operation of the ejector 114, the melting unit 120, and the level meter 139. Particularly, the controller 140 determines whether the molten alloy iron is additionally manufactured using the measurement result of the level meter 139, and determines whether the molten alloy iron is produced by the discharger 114 and the molten iron 120, respectively. This will be described later in the alloy steel manufacturing method.

2 is a schematic view showing an apparatus for manufacturing an alloy steel according to a modification of the present invention.

2, an apparatus for producing an alloy steel according to a modified example of the present invention may have a configuration substantially similar to that of the alloy steel manufacturing apparatus according to the embodiment of the present invention described above, except for the configuration of the molten iron- have.

The molten alloy iron reservoir 2 may include a body 2 in which molten iron is stored and a cover 2 provided in the upper portion of the body 2. [ At this time, the body 2 may be formed with a discharge port 138a through which the molten iron is discharged, and the discharge port 138a may be formed on the lower side wall of the body 132. [ The outlet 138a may be provided with a valve 2 for opening and closing the flow passage in the discharge port 138a so as to control the flow rate of the molten iron discharged through the discharge port 138a. The outlet 138 may be provided with a sensor 133 for measuring the flow rate or flow rate of the discharged molten alloy iron so as to measure the discharged amount of the discharged molten iron alloy.

At this time, the measured result of the sensor 133 is transmitted to the controller 140, and the controller 140 calculates the amount of the molten iron contained in the body 132 using the result measured by the sensor 133 . The control unit 140 may determine whether the molten alloy is manufactured according to the calculated amount of the molten alloy and control the operation of the discharger 114 and the molten steel 120 according to the determination result.

According to the above-described structure, the apparatus for producing an alloy steel according to the present invention dissolves ferroalloys to produce molten ferroalloys and directly injects them into the molten ferroalloys 130 without the need to move the molten ferroalloys, The temperature drop or contamination due to the movement of the heater can be minimized.

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

FIG. 3 is a block diagram conceptually illustrating an alloy steel manufacturing method according to an embodiment of the present invention, and FIG. 4 is a view illustrating a process of manufacturing an alloy steel by an alloy steel manufacturing method according to an embodiment of the present invention.

A method for manufacturing an alloy steel according to an embodiment of the present invention includes the steps of preparing a molten steel (S110), preparing a molten alloy iron by dissolving ferroalloy (S120), injecting the molten alloy iron into a molten iron- (S130) of storing the molten alloy at a temperature equal to or higher than the melting point, and a step (S170) of mixing the molten steel with the molten alloy (S170). In the process of storing the molten alloy at a temperature equal to or higher than the melting point, And injecting the molten alloy into the molten iron iron reservoir.

The process of preparing the molten steel may be carried out as follows.

The molten steel produced in the blast furnace is put into the converter (10), and the molten steel is manufactured according to the necessary conditions such as blowing and talline. The molten steel having undergone the refining of the electric furnace is led from the converter 10 to the ladle 20 and transferred to the electric furnace where the molten iron is produced. Here, the molten steel produced in the blast furnace is described as being furnished and refined, but the molten steel may be produced in an electric furnace.

The process of preparing the molten alloy iron includes the steps of injecting the ferroalloy stored in the raw material reservoir 112 into the melting furnace 122 using the discharger 114 and supplying the heat source to the melting furnace 122 through the heat source supply unit 128 And dissolving the ferroalloys.

At this time, the alloy iron to be injected into the melting furnace 122 may be manganese (Mn) -based alloy iron such as FeMn or manganese metal. Here, the manganese metal is not alloy iron, but is called alloy iron for convenience of explanation.

The alloy iron is discharged into the melting space of the melting furnace 122 at a constant rate by using the discharger 114 when the alloy iron is melted in the melting furnace 122. The alloy iron is heated by the heat source supplied from the heat source supply unit 128, ≪ / RTI > and can be made of molten alloy iron. After the molten alloy iron is temporarily stored in the melting space, the molten alloy iron is tilted and injected directly into the molten iron iron reservoir 130 through the discharge port 126. The second stop 137b may be opened to open the opening 136 and the opening 136 may be closed after the injection of the molten iron alloy is completed before the molten iron iron is injected into the molten iron iron reservoir 130 .

As described above, the production of the molten alloy iron is carried out in a predetermined amount, that is, the maximum amount that can be stored in the molten alloy iron storage unit 130 or the amount of the molten alloy which is used in the molten alloy iron storage unit 130 It can be repeatedly performed until it is stored. This is because the amount of the molten alloy iron is measured in the course of storing the molten alloy iron (S140), and the measured amount of the molten alloy iron is compared with the reference amount (S150). When the measured amount is less than the reference amount, And this process can be repeatedly performed until the measured amount becomes equal to or similar to the reference amount. If the measured amount of the molten alloy iron is equal to or larger than the reference amount, the molten iron can be continuously stored in the molten steel, or the molten iron can be continuously mixed with the molten steel in accordance with whether or not the molten alloy is measured (S160).

When the molten alloy iron is provided, the molten alloy iron may be stored in the molten iron iron reservoir 130 until it is mixed with molten steel. In the process of storing the molten alloy iron, an atmosphere gas such as an inert gas or the like may be supplied to the molten iron iron reservoir 130, thereby performing the denitration treatment of the molten iron alloy.

Thereafter, when molten steel is prepared and transported to the mixing room, molten iron can be boiled through the discharge port 138 of the molten iron storage unit 130 to be mixed with the molten steel.

The amount of the molten iron is continuously measured even after the molten iron is boiled, and the molten alloy iron may be additionally prepared and stored in the molten iron iron reservoir 130 according to the measurement result.

After the molten steel and the molten alloy are mixed, the alloy steel may be refined (S180) such as vacuum refining or ladle furnace processing. Through this, it is possible to perform a dehydrogenation treatment for removing the hydrogen component in the alloy steel, a denitration treatment for removing the nitrogen component, and the step of raising the temperature of the alloy steel can be performed. In addition, the refining process also has the effect of stirring the alloy steel, so that the molten steel and the molten alloy can be uniformly mixed. This process may be omitted as it is performed as needed.

Thereafter, the alloy steel may be transferred to a casting facility and used to cast a slab, steel plate, etc. (S190).

As described above, according to the present invention, since the molten alloy is produced in the molten zone and then stored directly in the molten alloy iron reservoir, the temperature of the molten alloy is reduced or the contamination due to contact with the atmosphere is minimized until the molten alloy is mixed with the molten steel can do. That is, since the molten alloy iron is directly injected into the molten alloy iron reservoir without storing it in a separate container after the manufacture of the molten alloy iron, the contact with the atmosphere is minimized to suppress or prevent the temperature drop or contamination will be.

Although the technical idea of the present invention has been specifically described according to the above embodiments, it should be noted that the above embodiments are for explanation purposes only and not for the purpose of limitation. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

110: feedstock supply unit 120:
130: Molten alloy iron storage device 140:

Claims (19)

An alloy iron supply part;
A melted portion provided at a lower portion of the alloy iron supply portion so as to be capable of tilting and dissolving the alloy iron supplied from the alloy iron supply portion to produce molten alloy iron;
A molten iron iron reservoir provided at a lower portion of the molten iron to directly inject the molten iron supplied from the molten iron and having an inner space formed therein for storing the molten iron;
A level meter for measuring a level of the molten alloy iron bath surface stored in the molten iron iron reservoir; And
A controller for controlling the operation of the alloy iron supply unit and the melted part according to the level of the melt surface of the molten alloy iron measured by the level meter;
. An alloy iron supply part;
A melted portion provided at a lower portion of the alloy iron supply portion so as to be capable of tilting and dissolving the alloy iron supplied from the alloy iron supply portion to produce molten alloy iron;
A molten iron iron reservoir provided at a lower portion of the molten iron to directly inject the molten iron supplied from the molten iron and having an inner space formed therein for storing the molten iron;
A flow meter for measuring the flow rate of the molten alloy iron discharged from the molten alloy iron reservoir; And
A controller for calculating the amount of the molten alloy iron stored in the molten iron iron reservoir according to the flow rate of the molten alloy iron measured in the anemometer and controlling the operation of the molten iron supply unit and the molten iron using the calculated result;
. The method according to claim 1 or 2,
The iron-
A raw material reservoir for storing the ferroalloy,
And an ejector for discharging the ferroalloy stored in the raw material reservoir to the melted portion. The method of claim 3,
The molten-
A melting furnace formed with a melting space in which the alloy iron is melted and having a discharge port formed at one side of the melting space to discharge the molten ferrous iron;
And a heat source supply unit for supplying a heat source to the melting space on the other side of the melting furnace. The method of claim 4,
Wherein the heat source supply unit uses plasma as a heat source. The method of claim 5,
Wherein the molten iron iron reservoir comprises:
A body having a top opened and a storage space in which the molten iron is stored,
And a cover provided to open and close the upper portion of the body,
An opening communicating with the discharge port is formed in the cover so that the molten iron can be injected into the storage space,
And an outlet is formed in the body so as to discharge the molten alloy iron. delete delete delete delete The method of claim 6,
The reservoir comprises:
And a heating unit for heating the molten alloy iron stored in the storage space. The method of claim 11,
Wherein the molten iron iron reservoir comprises:
And a gas supply unit for supplying an atmospheric gas to the storage space so as to control the atmosphere of the storage space. The method of claim 12,
And a ladle containing molten alloy iron discharged from the molten alloy iron reservoir. A process of preparing molten steel;
Melting iron alloy to prepare molten iron;
Injecting the molten alloy iron into a molten alloy iron storage vessel and storing the molten alloy iron at a temperature higher than the melting point; And
And melting the molten steel and the molten alloy iron,
The step of storing the molten alloy iron at a temperature higher than the melting point,
Measuring the amount of the fused iron alloy stored in the molten iron iron reservoir;
And melting the ferroalloy when the measured amount of the molten ferroalloy is less than a predetermined reference amount to further prepare the molten ferroalloy; And
And injecting the further produced molten alloy iron into the molten iron iron reservoir. 15. The method of claim 14,
The step of storing the molten alloy iron at a temperature higher than the melting point,
And denitrating the molten alloy iron in the molten alloy iron reservoir. 16. The method of claim 15,
Wherein the reference amount includes an amount greater than one time of molten alloy iron to be mixed with the molten steel. 18. The method of claim 16,
After the mixing process,
A method for manufacturing an alloy steel which performs refining of at least one of ladle furnace (LF) refining and vacuum refining. 18. The method of claim 17,
Wherein the denitration treatment is performed in the refining process. 19. The method of claim 18,
Wherein the alloy iron comprises manganese.

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