KR20170106073A

KR20170106073A - Method of refining molten steel

Info

Publication number: KR20170106073A
Application number: KR1020160029724A
Authority: KR
Inventors: 유철종
Original assignee: 주식회사 포스코
Priority date: 2016-03-11
Filing date: 2016-03-11
Publication date: 2017-09-20

Abstract

The present invention relates to a steel refining method. The steel refining method comprises: a step of refining molten steel in a converter; a step of tapping molten steel wherein refining is completed in the converter on a ladle; a primary measuring step of measuring a temperature (T1) of the molten steel in which refining is completed in the converter, and an oxygen concentration (C1) in the molten steel; a primary control step of supplying gas to the molten steel wherein refining is completed in the converter, stirring the molten steel and gas, and injecting at least one of a coolant and a deoxidizer in accordance with the temperature (T1) and the oxygen concentration (C1) of the molten steel measured in the primary measuring step to control a temperature of the molten steel and the inclusions of the molten steel; a secondary measuring step of measuring a temperature (T2) and an oxygen concentration (C2) of the molten steel wherein the primary control step is completed; a secondary control step of supplying gas to the molten steel wherein the primary control step is completed, stirring the molten steel and the gas, and injecting at least one of a coolant and a deoxidizer into the molten steel in accordance with the temperature (T2) and the oxygen concentration (C2) of the molten steel measured in the secondary measuring step to control the temperature of the molten steel and the inclusions of the molten steel; and a step of transferring the molten steel to a continuous casting facility when the secondary control step is completed. As the inclusions contained in the molten steel are controlled by bubbling the molten steel refined in the converter to omit a subsequent secondary refining process, the time required to refine molten steel is able to be shortened; thereby improving productivity and reducing costs required to manufacture the molten steel.

Description

[0001] METHOD OF REFINING MOLTEN STEEL [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel refining method, and more particularly, to a steel refining method capable of easily controlling inclusions in molten steel.

Generally, molten steel refined in a converter is homogenized by a bubbling process in a BAP (Bubbling Aluminum Power), and then subjected to a ladle furnace (LF) facility and a Rheinstahl-Heraus Gas) facility and then supplied to the continuous casting facility.

In the preheating treatment plant of molten steel, molten steel is sampled to measure the temperature of molten steel and the oxygen concentration in the molten steel, and the temperature of the molten steel is controlled and the oxygen concentration in the molten steel is controlled according to the measurement result. When the temperature and oxygen concentration of the molten steel are adjusted, the molten steel is transferred to the secondary refining facility, the LF facility or the RH facility, to refine the secondary steel.

However, there is molten steel that does not require secondary refining in LF equipment or RH equipment depending on the type of molten steel. Such molten steel can be used directly in continuous casting by simply removing inclusions contained in molten steel in the preheating area of molten steel.

However, irrespective of this, the molten steel refined in the converter is removed from the molten steel preliminary treatment plant and then transported to the LF equipment or the RH equipment for processing, resulting in inefficient refining of the molten steel, resulting in a decrease in productivity and an increase in production cost .

In addition, since it takes a long time to process molten steel, the temperature of the molten steel is inevitably lowered, which causes the refining temperature of the molten steel to increase at the time of turning the molten steel, thereby causing the refractory of the converter to be molten or the molten steel component to become unstable.

KR10-1207669B KR10-0833040B KR10-1434540B KR2000-0042054A

The present invention provides a steel refining method capable of easily controlling inclusions in molten steel.

The present invention provides a steel refining method capable of improving productivity and reducing production costs.

A steel refining method according to an embodiment of the present invention includes a process of refining molten steel in a converter; Introducing molten steel having been refined in the converter into the ladle; A first measuring step of measuring a temperature (T1) of refined molten steel in the converter and an oxygen concentration (C1) in the molten steel; Wherein at least one of a coolant and a deoxidizer is charged in accordance with the temperature T1 and the oxygen concentration C1 of the molten steel measured in the first measuring step, A primary control process for controlling inclusions in temperature and molten steel; A second measuring step of measuring the temperature (T2) and the oxygen concentration (C2) of the molten steel for which the primary control process has been completed; Wherein at least one of the coolant and the deoxidizer is added to the molten steel in accordance with the temperature (T2) and the oxygen concentration (C2) of the molten steel measured in the secondary measurement process while supplying the gas to the molten steel after the primary control process is completed To control the temperature of the molten steel and the inclusions in the molten steel; And transferring molten steel to the continuous casting facility when the secondary control process is completed.

The time for refining the inclusions in the molten steel is determined in the process of refining the molten steel in the converter, and the time (t1, t2, t3) from the primary measurement to the start of casting ) And a temperature value at which the molten steel is cooled for the required time, thereby controlling the transition end temperature (T0) of the molten steel during the refining of the converter.

During the ladle-casting process, ferroalloy may be charged into molten steel that has been refined in the converter.

If the temperature T1 of the molten steel measured in the primary measuring process is higher than the temperature obtained by subtracting the temperature Ta at which the molten steel is cooled during the primary control process at the transition end point temperature T0 , The coolant may be supplied to the molten steel so that the measured temperature T1 of the molten steel has a temperature obtained by subtracting the temperature value Ta at which the molten steel is cooled during the primary control process at the converter end temperature T0.

When the oxygen concentration in the molten steel measured in the first measurement process is higher than the predetermined oxygen concentration in the first control process, the deoxidizer may be injected into the molten steel.

The primary control process may be performed for 5 to 8 minutes.

In the secondary control process, the temperature T2 of the molten steel measured in the secondary measuring process is a value at which the molten steel is cooled in the primary control process and the secondary control process at the transition end temperature T0 (Ta + Tb) at which the measured molten steel temperature (T2) is lower than the transition end temperature (T0) at which the molten steel is cooled during the primary control process and the secondary control process, ) Can be added to the molten steel.

In the secondary control process, the molten steel may be adjusted to a casting temperature (T10).

In the secondary control process, if the oxygen concentration (C2) in the molten steel measured in the secondary measurement process is higher than the predetermined oxygen concentration, the deoxidizer may be supplied to the molten steel.

The secondary control process may be performed for 4 to 8 minutes.

In the primary control process and the secondary control process, the inert gas may be supplied at 60 to 80 Nm 3 / hr.

The time required from the primary measurement to the secondary control may be 10 to 18 minutes.

The temperature and the oxygen concentration of the molten steel may be measured after the secondary control process and at least one of the coolant and the deoxidizer may be introduced depending on the measured result to control the temperature of the molten steel and the inclusions in the molten steel .

According to the embodiment of the present invention, the subsequent secondary refining step can be omitted by controlling the inclusions contained in the molten steel by bubbling the molten steel refined in the converter. Therefore, omitting the secondary refining process can shorten the time required to refine the molten steel, thereby improving the productivity and reducing the cost of manufacturing the molten steel.

In addition, since the time required for processing the molten steel can be shortened, the energy cost caused by the temperature drop of the molten steel can also be reduced.

In addition, considering the lowering of the temperature of the molten steel which may occur during the secondary refining, the temperature of molten steel at the time of excavation does not need to be increased, that is, the target temperature of the molten steel is not increased. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a refining apparatus for refining steel by refining steel according to an embodiment of the present invention; FIG.
2 is a flowchart showing a steel refining method 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 a refining apparatus for refining steel by refining steel according to an embodiment of the present invention.

1, the refining apparatus includes a ladle 100 that receives refined molten steel in a converter, stirring means 200 for stirring molten steel in the ladle 100, An additive supplying means 300 for injecting an additive into the molten steel accommodated in the ladle 100 for adjusting the component of the molten steel and a molten steel sampled by the steel means of the molten steel and the sampling means 400 And control means 500 for controlling the operation of the agitation means 200 and the additive supply means 300 according to the analysis result.

The ladle 100 receives the refined molten steel from the converter and can be mounted on the movable bogie 110 and transferred to the molten steel treatment place. The ladle 100 may be provided with a space for accommodating molten steel therein, an upper portion thereof opened, and a lower portion, for example, a bottom portion thereof may be provided with a deodorizing nozzle 102 capable of blowing gas into molten steel. The low-noise nozzle 102 may be provided with a low-noise nozzle valve 212 for opening and closing the low-noise nozzle 102. The lid 100 may be provided with a cover 120 for suppressing the scattering of molten steel during molten steel treatment. The cover 120 may be provided with a through hole through which the additive, the lance 220 and the sampling means 400 are inserted. Can be formed.

The stirring means 200 may be a device for stirring the molten steel in the ladle 100 and supplying the gas into the ladle 100. The agitating means 200 includes a gas storage portion (not shown) for storing a gas and an inert gas such as argon (Ar), which is provided on the ladle 100 so as to be movable up and down, And may include an injecting lance 220. The lance 220 may be provided with a lance valve 224 for controlling gas supply to and shut off of the lance 220. The agitation means 200 includes a first gas supply pipe 210 communicating with a gas storage unit (not shown) and connected to a low-noise nozzle 102 provided at the bottom of the ladle 100, a lance 220, And a second gas supply pipe 222 connected to the second gas supply pipe 222.

The additive supply means 300 may include a storage portion 310 for storing the additive and an additive supply line 320 for use as a path for moving the additive. The storage unit 510 may include a coolant hopper 312a and a deoxidizer hopper 314a for storing a coolant for adjusting the temperature of molten steel and a deoxidizer for adjusting the oxygen concentration in the molten steel, The deoxidizer hopper 314a may include a feeder 312b 314b for discharging a coolant and a deoxidizer by a predetermined amount. Between the coolant hopper 312a and the deoxidizer hopper 314a and the additive feed pipe 320 may be provided a mixing hopper 316a for mixing or temporarily storing coolant and deoxidizer and supplying the coolant and deoxidizer to the ladle 100, The mixing hopper 316a may be provided with a feeder 316b for uniformly discharging a coolant and a deoxidizer. The coolant and the deoxidizer discharged from the storage part 510 can be introduced into the molten steel through the additive supply pipe 320.

The sampling means 400 is vertically movable on the ladle 100 so that at least a part of the molten steel is immersed in the ladle 100 to collect a part of the molten steel. The sampling means 400 includes a probe 412 for collecting molten steel, a support 420 for supporting the probe 412, and a driver 410 for moving the probe 412 in the vertical direction on the support table 420 . In addition, the sampling means 400 may include a temperature measuring device moving in the vertical direction by the driver 410, and may directly measure the temperature of the molten steel by being immersed in the molten steel. With this configuration, the sampling means 400 can measure the temperature of the molten steel and simultaneously measure the components of the molten steel, for example, the oxygen concentration in the molten steel. The molten steel component and the temperature measured by the sampling means 400 may be transferred to the control means 500 to set refining conditions.

In addition, the molten steel sampled by the sampling means 400 may be sent to an analysis room or the like for component analysis, and component analysis may be performed.

The control unit 500 includes a storage unit 510 for storing molten steel information such as a steel grade, a component and a temperature of molten steel refined in a converter, information on molten steel stored in the storage unit 510, An operation unit 520 for calculating the control conditions of the molten steel by comparing the temperature and the oxygen concentration of the molten steel and the operation of the stirring means 200 and the additive supply means 300 according to the control conditions of the molten steel calculated by the calculation unit 520 And a control unit 530 for controlling the operation of the sampling means 400.

The storage unit 510 is configured to determine the flow of the downstream process if the steel type is determined on the basis of the production schedule or the like. The storage unit 510 stores the information on the molten steel refined in the converting process, the amount of the iron alloy to be supplied to the molten steel, And information such as the end point temperature and the oxygen concentration of the converter. In addition, the storage unit 510 may store processing information of the molten steel for which the refining has been completed.

The calculation unit 520 compares the information stored in the storage unit 510 with the measurement result of the sampling unit 400 to calculate the control condition of the molten steel and transmits the control condition to the control unit 530.

When the ladle 100 is transferred to the molten steel treatment position, the operation unit 520 detects the sensor 112 installed at the molten steel treatment position and transmits the detection result to the control unit 530. The control unit 530 controls the molten steel A process for controlling the temperature and the composition of the reaction product is performed.

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

2 is a flowchart showing a steel refining method according to an embodiment of the present invention.

Referring to FIG. 2, the method of refining steel according to the embodiment of the present invention includes a step S100 of refining a refractory steel, a step S102 of introducing molten steel into the ladle 100, (S104) of transferring the molten steel to a molten steel pre-treatment plant or a rice (BAP) plant (S104), a primary measurement process (S108) for controlling the temperature of the molten steel and the inclusions in the molten steel by injecting at least one of a coolant and a deoxidizer into the molten steel according to a measurement result of the first measuring process, (S110) for measuring the temperature (T2) and the oxygen concentration (C2) of the molten steel for which the first control process is completed, and the second measurement process The temperature of the molten steel and the inclusion in the molten steel (S112) for controlling the molten steel to a continuous casting facility (S114).

In the process of refining the converter, molten steel can be manufactured by charging charcoal and scrap into the converter, and by blowing oxygen-containing gas to dissolve the scrap while controlling the concentration of impurities in the charcoal.

The amount of iron alloy to be added to molten steel is determined according to the type of molten steel that is finally produced during refinement. In addition, the treatment of the molten steel for which the furnace refining has been completed, for example, the purpose of the secondary refining and the secondary refining process conditions for the purpose are determined according to the steel grade of the molten steel during refining. The present invention relates to a method for casting refractory molten steel that has been refined by passing through only bubbling in a bamboo plant and then transferring the refractory molten steel to a continuous casting facility for casting. Second refining purpose of the molten steel is control of inclusions in molten steel. At least two times of measuring the temperature and oxygen concentration of the molten steel and at least one of the coolant and the deoxidizer to the molten steel according to the result of the measurement to control the temperature of the molten steel and the inclusions in the molten steel. Therefore, in the present invention, it is possible to improve the process efficiency and productivity by controlling only the temperature and inclusion of molten steel, and then conveying the molten steel to a continuous casting facility without passing through the LF facility or the degassing facility.

When the molten steel having been refined in the converter has the components as shown in Table 1 below, the kind and content of the ferroalloy to be fed into the molten steel can be calculated.

Molten steel component maximum goal Lower limit C (%) 0.23 0.21 0.19 Si (%) 0.03 0 Mn (%) 0.3 0.25 002 P (%) 0.03 0 S (%) 0.02 0 Cu (%) 0.06 0 S-Al (%) 0.04 0.02 0.01 Nb (%) 0.01 0 Ni (%) 0.1 0 Cr (%) 0.1 0 Mo (%) 0.08 0 Ti (%) 0.02 0 V (%) 0.01 0 Ca (%) 0 0 Sb (%) 0.01 0 Sn (%) 0.02 0 N (%) 0.01 0

Referring to Table 1, the ferroalloys to be fed into the molten steel are carbon (C), manganese (Mn), and aluminum (Al). At this time, since the deviation of the rate of realization occurs, aluminum is weighed through the value of the operating performance and can be generally weighed to about 400 to 500 kg.

The input amount of the ferroalloy can be calculated by the following equation (1).

For example, the molten steel amount is 275,000 kg, the converter end carbon content 0.03%, the converter end manganese content 0.08%, the real rate of the alloy iron petroleum agent is 85%, the carbon content is 100%, the manganese content of ferromanganese (Fe- , The carbon content in manganese is 6.8%, and the rate of water loss is 95%, it is desirable to estimate the amount of iron alloy input as follows.

First, substituting the amount of ferromanganese into equation 1, weigh 656 kg. However, in order to match the carbon value, the amount of the carbon monoxide contained in the ferromanganese is calculated first, which is a value of 45 kg multiplied by the carbon content in the amount of ferromanganese. The amount of the gadolinium additive is calculated by the above equation (1), and 582 kg is calculated. If this value is weighed, the component may deviate to the upper limit. Therefore, if the calculated value is subtracted from the amount of the carbon monoxide contained in the ferromanganese, it is necessary to weigh 537 kg. Thus, the alloy iron is weighed 537 kg of petroleum, 656 kg of ferromanganese, and 400 kg of aluminum. In order to remove the nonmetallic inclusions by separating them, the slag refinement material is weighed in a weight of 500 kg.

When the calculation of the alloy steel basis value is completed, the converter end point temperature T0 is calculated. That is, the target temperature T0 of the molten steel at the completion of the refining of the converter is calculated. First, the casting target temperature T10 is checked and the time (t1, t2) at which the molten steel is processed in the bobbin and the time (t3) from the completion of the processing of the molten steel to the start of casting in the bobbin are calculated, The value of the temperature drops every minute. In addition, the temperature values (Ta, Tb) at which the molten steel is cooled during the molten steel treatment through bubbling in the bamboo plant are obtained. (Ta + Tb + Tc) obtained by adding the above three values to the casting target temperature (T10) is calculated at the completion of the refining of the molten steel The target temperature T0 is set to the target temperature T0. For example, assuming that the casting target temperature T10 is 1541 deg. C, the time from completion of control of inclusions in the molten steel to the start of casting is 45 minutes (t3), the primary control process is 5 minutes (t1) The temperature at which the molten steel is cooled from the completion of the control of the inclusions in the molten steel to the start of casting is 40.5 ° C. (Tc ), The target temperature (T0) of the molten steel is about 1631 ° C. when the temperature to be cooled is 15 ° C. in the first control process, 20 ° C. (Tb) in the second control, . In this case, the time required for the primary control process and the secondary control process may include the time required for the primary measurement process and the secondary measurement process.

When the carbon value is 0.03%, the refining ends. When the temperature of the molten steel is lower than the target temperature (T0), that is, the converter end temperature, the oxygen is supplied again to the molten steel, .

When the refining of the converter is completed, molten steel is introduced into the ladle 100. At this time, the molten steel may be supplied with molten iron before molten steel is introduced, and the molten steel may be supplied when molten steel is introduced into the ladle 100 by 1/3 to 2/3 of the molten steel. If molten iron is injected sooner than the suggested range, the temperature of the molten steel may drop sharply. If the molten iron is injected later than the specified range, the amount of slag is increased due to oxidation of the ferroalloy.

The ladle 100 is transported to the bamboo basket by the bogie 110. When the ladle 100 reaches the ladle processing position of the bamboo basket, So that the bogie 110 stops.

The sensor 112 transmits information that the ladle 100 has arrived at the ladle processing position to the operation unit 520 of the control means 500. When the operation unit 520 delivers the information to the control unit 530, .

In the primary measurement step S106, the temperature T1 of the molten steel is measured using the sampling means 400, and a part of the molten steel is sampled to measure the oxygen concentration of the molten steel. Here, the temperature T1 of the molten steel is affected by the oxygen concentration in the molten steel, the ladle condition, and the like. Therefore, the arrival temperature to the brewery is checked and the cooling time or the bubbling time , And the oxygen concentration in the molten steel is measured to determine the aluminum concentration in the molten steel. At this time, the first measurement process can be performed for 30 to 60 seconds.

After the first measuring process, the controller 530 opens the low-noise nozzle valve 212 provided in the low-noise nozzle 102 and injects gas such as argon gas through the low-noise nozzle 102 to stir the molten steel, (Step S108). At this time, the molten steel may be agitated by injecting gas through the lance 220 on the ladle 100 without using the low-noise nozzle 102.

In the course of stirring the molten steel, the gas can be supplied at a rate of about 60 to 80 Nm 3 per hour through the inert gas nozzle 102. If the amount of the supplied gas is less than the suggested range, the molten steel can not be effectively stirred. And because of the limitations of facility capacity, it is difficult to supply more gas than the range suggested.

When the primary control process is performed for a shorter time than the suggested range, stirring of the molten steel is not smooth, so that the molten iron is not dissolved sufficiently before the stirring, It is inevitable that the temperature of the molten steel is lowered.

During the primary control process, at least one of the coolant and the deoxidizer may be injected into the molten steel using the results measured in the first measurement process to control the temperature of the molten steel and the inclusions in the molten steel.

When the measured temperature T1 is higher than a predetermined temperature, that is, a temperature obtained by subtracting the temperature value Ta at which molten steel calculated at the refining is converted at the convergence end point temperature T0, the molten steel is cooled at the transition end temperature T0 The temperature of the molten steel can be lowered by injecting the coolant into the molten steel so as to have a temperature obtained by subtracting the temperature value (Ta) at which the molten steel calculated during the refining of the converter is cooled. Here, the temperature of the molten steel is controlled by the converter so as to maintain the casting temperature even if the temperature is lowered by performing the primary control and the secondary control process. Therefore, in the first measurement, . The temperature T1 measured in the first measuring process is determined by measuring 1000 kg of the coolant stored in the coolant hopper 312a of the additive supply means 300 when the measured temperature of the molten steel is 5 DEG C higher than the preset temperature, can do.

Further, when the measured oxygen concentration C1 is measured to be higher than the target oxygen concentration, that is, the preset oxygen concentration, it is determined that the aluminum concentration in the molten steel is low, and the oxygen concentration in the molten steel can be lowered by injecting the deoxidizer into the molten steel. For example, when the measured oxygen concentration of the molten steel is -130 mV, the deagglomerator does not need to be charged because the slag in the ladle is in a stable state. If the oxygen concentration is measured at 1615 캜 at -50 mV, the aluminum concentration in the molten steel is about 0.005% Since deoxidation is unstable, aluminum may be added to the aluminum through the deoxidizer hopper 314a so as to stabilize the aluminum to 1.4 to 1.6 kg per 10 mV and adjust to -130 mV.

In addition, the time (t1) required for the primary control process can be varied depending on the oxygen concentration in the molten steel, and can be appropriately adjusted within the above-described range depending on whether deoxidizing agent is input or not. For example, when the deoxidizer is not added, the time required for the primary control process may be shorter than when the deoxidizer is added.

When the primary control process is completed, the second measurement process of stopping the supply of the gas to the molten steel and operating the sampling means 400 to measure the temperature (T2) of the molten steel and the oxygen concentration (C2) in the molten steel .

The secondary measurement process can be performed in the same manner as the primary measurement process described above.

When the secondary measurement process is completed, a secondary control process is performed in which molten steel is stirred by supplying gas through the lance 220 or the low-noise nozzle 102.

If the primary control process is intended to dissolve ferroalloys fed to the molten steel to uniformize the molten steel components, the secondary control process aims at controlling the temperature of the molten steel and the inclusions in the molten steel. Control of inclusions in molten steel is a process in which when aluminum in molten steel reacts with oxygen in molten steel to produce alumina, the alumina in the molten steel is slagged by bubbling according to the gas supply.

The secondary control process can supply the gas of about 60 to 80 Nm 3 per hour through the low-noise nozzle 102 in the process of stirring the molten steel, and can not effectively stir the molten steel when the amount of supplied gas is less than the suggested range. And because of the limitations of facility capacity, it is difficult to supply more gas than the range suggested.

The time t2 during which the secondary control process is performed can be performed for about 4 to 8 minutes. When the secondary control process is performed for a time shorter than the suggested range, the stirring of the molten steel is not smooth, It is inevitable to lower the temperature of the molten steel when it is carried out for a longer time than the suggested range.

The secondary control process determines the gas supply time and whether the coolant and deoxidizer are input according to the temperature (T2) of the molten steel measured by the secondary measurement process and the oxygen concentration (C2) in the molten steel. The coolant and deoxidizer can be introduced in the same manner as the first control process.

In this case, in the second control process, the temperature (T2 + Tb) of the molten steel measured in the second measuring process is the temperature at which the molten steel is cooled in the first control process and the second control process at the transition end temperature (T0) If the temperature is higher than the subtracted temperature, the coolant may be supplied to the molten steel so that the molten steel is cooled at the transition end temperature (T0) to a temperature obtained by subtracting the temperature value (Ta + Tb) at which the molten steel is cooled during the primary control process and the secondary control process have.

When the secondary control process is completed, the gas supply is stopped and the ladle 100 is transferred to the continuous casting facility. At this time, the temperature of the molten steel and the oxygen concentration in the molten steel can be measured before the ladle 100 is transferred to the continuous casting facility. When the temperature of the molten steel reaches the upper limit of the casting temperature and the lower limit of 3 ° C, . At this time, casting is not possible when the temperature of the molten steel is 3 ° C higher than or lower than the casting temperature.

If the oxygen concentration of the molten steel measured after the completion of the secondary control process is higher than a predetermined value, the control for controlling the inclusions in the molten steel may be unnecessary because the inclusions in the molten steel are removed. The process can be repeated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. 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.

100: Ladle 102: Deodorizing nozzle
110: Bogie 112: Sensor
120: cover 200: stirring means
210: first gas supply pipe 212: low noise nozzle valve
220: Lance 222: Second gas supply pipe
224: lance valve 300: additive supply means
310: storage part 320: additive supply pipe
400: sampling means 410: driver
412: Probe 420: Support
500: Control means 510:
520: Operation unit 530:

Claims

The process of refining molten steel in a converter;
Introducing molten steel having been refined in the converter into the ladle;
A first measuring step of measuring a temperature (T1) of refined molten steel in the converter and an oxygen concentration (C1) in the molten steel;
Wherein at least one of a coolant and a deoxidizer is charged in accordance with the temperature T1 and the oxygen concentration C1 of the molten steel measured in the first measuring step, A primary control process for controlling inclusions in temperature and molten steel;
A second measuring step of measuring the temperature (T2) and the oxygen concentration (C2) of the molten steel for which the primary control process has been completed;
Wherein at least one of the coolant and the deoxidizer is added to the molten steel in accordance with the temperature (T2) and the oxygen concentration (C2) of the molten steel measured in the secondary measurement process while supplying the gas to the molten steel after the primary control process is completed To control the temperature of the molten steel and the inclusions in the molten steel; And
Transferring the molten steel to the continuous casting facility when the secondary control process is completed;
Wherein the steel refining method comprises:

The method according to claim 1,
The time for refining the inclusions in the molten steel is determined in the process of refining the molten steel in the converter, and the time (t1, t2, t3) from the primary measurement to the start of casting ) And a temperature value (Ta, Tb, Tc) at which the molten steel is cooled for the required time to control the converter end temperature (T0) of the molten steel during the refining of the converter.
(T1 is time required for the primary control process, t2 is time for the secondary control process, t3 is time for the secondary control process to start casting injection, Ta is the time for cooling the molten steel in the primary control process Tb is the temperature value at which molten steel is cooled during the secondary control process, and Tc is the temperature value that is cooled during the process of moving to the continuous casting facility after the secondary control process.)

The method of claim 2,
The method of refining steel as set forth in claim 1,

The method of claim 3,
In the primary control process,
When the temperature T1 of the molten steel measured in the first measuring step is higher than the temperature obtained by subtracting the temperature Ta at which the molten steel is cooled in the first control process at the converter end point temperature T0, Wherein the coolant is supplied to the molten steel so that the temperature T1 of the molten steel has a temperature minus a temperature value Ta at which the molten steel is cooled during the primary control process at the converter end temperature T0.

The method of claim 4,
Wherein the deoxidizing agent is supplied to the molten steel when the oxygen concentration in the molten steel measured in the first measuring step is higher than a predetermined oxygen concentration in the primary control.

The method of claim 4,
Wherein the primary control process is performed for 5 to 8 minutes.

The method of claim 3,
In the secondary control process,
The temperature T2 of the molten steel measured in the second measuring process is lower than the temperature obtained by subtracting the temperature value Ta + Tb at which the molten steel is cooled during the primary control process and the secondary control process at the converter end temperature T0 (Ta + Tb) at which the temperature (T2) of the molten steel measured is lower than the temperature value (Ta + Tb) at which the molten steel is cooled at the conversion end temperature (T0) during the primary control process and the upper secondary control process, A method of refining a steel into which the steel is fed.

The method of claim 7,
Wherein the molten steel is controlled at a casting temperature (T10) in the secondary control process.

The method of claim 8,
The secondary control process includes:
And a deoxidizing agent is added to the molten steel when the oxygen concentration (C2) in the molten steel measured in the second measuring step is higher than a preset oxygen concentration.

The method of claim 9,
Wherein the secondary control process is performed for 4 to 8 minutes.

The method of claim 3,
Wherein the inert gas is supplied at 60 to 80 Nm < 3 > per hour in the primary control process and the secondary control process.

The method of claim 11,
Wherein the time taken from the primary measurement to the secondary control is from 10 to 18 minutes.

The method of claim 3,
A process of measuring the temperature and oxygen concentration of the molten steel after the secondary control process and controlling at least one of the temperature of the molten steel and the inclusion in the molten steel by injecting at least one of the coolant and the deoxidizer according to the measured result, Way.