KR101729191B1 - Manufacturing method for low-carbon manganese ferroalloy using complex top blowing of refining converter - Google Patents

Abstract

The method for manufacturing low-carbon manganese-based alloyed iron using the composite iron scouring according to an embodiment of the present invention includes: charging a high-carbon manganese-based alloyed iron-containing steel into a converter body; A first decarburization step of taking up a first offgas gas made of oxygen toward the upper surface of the molten steel and transversely taking a first transversal gas composed of a mixed gas of oxygen and an inert gas laterally in the molten steel; And a second offgas gas composed of a mixed gas of oxygen and an inert gas from a carbon critical point toward the upper surface of the molten steel and a second entangled gas composed of a mixed gas of oxygen and an inert gas is introduced into the molten steel in a lateral direction Wherein the carbon critical point is a point at which a secondary differential value of the molten steel decarburization rate is converted to a negative value, and in the second decarburization step, an oxygen demand amount W _O The second pickling gas and the second pickling gas are blown.

Description

Technical Field [0001] The present invention relates to a method for manufacturing a low-carbon manganese-based alloy steel using a composite iron-

The present invention relates to a process for producing low-manganese-based alloyed iron using a composite iron scouring, and more particularly, to a method for producing a low-carbon manganese-based alloyed iron from a high carbon manganese- .

A manufacturing method for producing a medium-low carbon manganese based alloy iron is a siliside method and a converter method. The silicide method is a method of charging silicon carbide as a manganese ore, a zircon, a conditioning agent, and a reducing agent into an electric furnace and performing a reduction refining to produce a silicon manganese alloy melt. The produced silicon manganese alloy molten metal is transferred to a separate electric furnace, and manganese ore is charged. The manganese reduction and the reoxidization of silicon are performed to produce a low carbon manganese based alloy iron. In the converter method, oxygen is blown into molten high carbon manganese-based alloyed iron to produce low-carbon manganese-based alloyed iron through decarburization reaction between carbon and oxygen in the molten metal. The converter method uses an upper lance that blows oxygen from the upper part of the molten metal and a tuyer that blows oxygen from the lower side of the molten metal to decantate the molten metal and decontaminate the molten metal.

Korean Patent Laid-Open Publication No. 10-2013-0078936 (published on October 10, 2013)

The present invention is to provide a production method capable of effectively producing low-carbon manganese-based alloy iron from a high-carbon-manganese-based alloy steel using composite iron scouring.

Other objects of the present invention will become more apparent from the following detailed description and drawings.

The method for manufacturing low-carbon manganese-based alloyed iron using the composite iron scouring according to an embodiment of the present invention includes: charging a high-carbon manganese-based alloyed iron-containing steel into a converter body; A first decarburization step of taking up a first offgas gas made of oxygen toward the upper surface of the molten steel and transversely taking a first transversal gas composed of a mixed gas of oxygen and an inert gas laterally in the molten steel; And a second offgas gas composed of a mixed gas of oxygen and an inert gas from a carbon critical point toward the upper surface of the molten steel and a second entangled gas composed of a mixed gas of oxygen and an inert gas is introduced into the molten steel in the lateral direction Wherein the carbon critical point is a point at which the differential value of the molten steel decarburization rate is converted to a negative value, and in the second decarburization step, the oxygen demand W _o calculated by the following formula 1 The second pickling gas and the second pickling gas are taken in.

<Formula 1>

W _O = {(W _CT -W _CC ) / 12} * 16 / E _O

In Equation 1, W _O is the oxygen demand (g), W _CT is the total carbon content (g) contained in the molten metal, W _CC is the amount of carbon removed to the carbon threshold (g), and E _O is the oxygen efficiency.

The oxygen efficiency E ₀ of the formula 1 may be 0.75-0.85.

The inert gas may be any one selected from the group consisting of argon gas (Ar) and nitrogen gas (N ₂ ).

The second offgas gas may have a mixing ratio of oxygen and an inert gas of 1: 0.05 to 1.5.

The second offgas gas may be formed into a turbulent flow.

The second offgas gas may have a Raynold Number of 2100 or more.

The second decarburization step may be performed so that the flow rate of the second offgas gas is maintained to maintain the first offgas gas flow rate in the first decarburization step.

The flow rate of the first and second offgas may be 2000 to 2400 Nm ³ / hr.

The partial pressure of CO gas in the converter body in the second decarburization step may be 0.550 to 0.778.

An apparatus for manufacturing low-carbon manganese-based alloy iron using a composite inductively refining method according to an embodiment of the present invention includes a converter body having a space capable of accommodating a molten metal therein; A tuyer unit disposed in a lower side wall of the converter main body and capable of transversely transversely injecting gas in a molten metal accommodated in the space; A lance unit for selectively introducing the off-gas into a second off-gas containing a first off-gas consisting of oxygen and a mixed gas of oxygen and an inert gas, the off-gas being directed toward the upper surface of the molten metal accommodated in the space; And a controller electrically connected to the lance unit to control the lance unit.

The lance unit includes an oxygen supply pipe to which oxygen is supplied; An inert gas supply pipe connected to the oxygen supply pipe to supply an inert gas to the oxygen supply pipe; And a diffuser member connected to a front end of the inert gas supply pipe and disposed in the oxygen supply pipe, wherein the plurality of injection holes are formed to form the second offgas gas in a turbulent flow.

The second offgas from the lance unit may have a Raynold Number of 2100 or more.

Wherein the lance unit comprises: an oxygen valve member disposed on the oxygen supply pipe to adjust an amount of oxygen of the outgoing gas; And an inert gas valve member disposed on the inert gas supply pipe to adjust an inert gas amount of the offgas gas, wherein the tuner unit includes an intercepted gas valve for regulating a supply amount of the entrained gas and a mixing ratio of the entrained gas, And the control unit may control the oxygen valve member, the inert gas valve member, and the intercepted gas valve member.

Wherein the control unit controls the lance unit such that the lance unit superimposing the first offgas gas picks up the second offgas from the carbon critical point, wherein the carbon critical point is a point at which the differential value of the molten steel decarburization rate is converted to a negative value Lt; / RTI &gt;

The control unit may control the lance unit and the tuyer unit so that the oxygen amount supplied into the converter body from the carbon critical point satisfies the oxygen demand (W _O ) in Equation (1).

<Formula 1>

W _O = {(W _CT -W _CC ) / 12} * 16 / E _O

In Equation 1, W _O is the oxygen demand (g), W _CT is the total carbon content (g) contained in the molten metal, W _CC is the amount of carbon removed to the carbon threshold (g), and E _O is the oxygen efficiency.

The oxygen efficiency (E ₀ ) of the formula 1 may be 0.75 to 0.85.

The inert gas may be any one selected from the group consisting of argon gas (Ar) and nitrogen gas (N ₂ ).

The effect of the method for producing low-manganese-based alloyed iron using the composite iron scouring according to an embodiment of the present invention will be described as follows.

The manganese (Mn) loss rate of the final product can be minimized by gradually introducing the offgas mixed with oxygen (O ₂ ) and oxygen (O ₂ ) and inert gas in the refining process of the manganese ferrofibers. Further, in the stepwise blowing of the offgas gas, it is possible to blow at the maximum flow rate without changing the flow rate of the offgas, and to form the offgas gas into the turbulent flow and blowing it, thereby maximizing the decarburization efficiency.

Accordingly, the method for manufacturing low-carbon manganese-based alloyed iron using the composite iron scouring according to an embodiment of the present invention can produce high-quality low-carbon manganese-based alloyed iron and can effectively reduce the manufacturing cost.

1 is a schematic view showing an example of a converter for producing low-carbon manganese-based alloy iron.
FIG. 2 is a schematic view of an apparatus for producing low-carbon manganese-based alloy iron using the composite iron scouring of the present invention.
FIG. 3 is a flow chart schematically illustrating a method of manufacturing low-carbon manganese-based alloyed iron using a composite iron scouring method according to an embodiment of the present invention.
4 and 5 are views schematically showing the operation of the apparatus for manufacturing low-carbon manganese-based alloy iron using the composite iron scouring of the present invention.
6 is a graph showing the decarburization rate and demagnetization rate.
7 is a view schematically showing a diffuser member.

The present invention relates to a method for producing low-carbon manganese-based alloyed iron using a composite iron scouring method, and embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments are provided to explain the present invention to a person having ordinary skill in the art to which the present invention belongs. Accordingly, the shape of each element shown in the figures may be exaggerated to emphasize a clearer description. Also, the connection referred to below should be construed to include not only when two components are directly connected but also indirectly connected through another medium.

1 is a schematic view showing an example of a converter apparatus for producing low-carbon manganese-based alloy iron.

As shown in FIG. 1, a converter device 1 for performing a refining operation of manganese-based alloy iron has a converter body 2 having a space 6 formed therein, and a space 6 of the converter body 2, Manganese-based alloy iron melt 5 is accommodated. A tuyer 4 transversely receiving transversal gas is arranged inside the molten metal 5 on the lower side of the converter body 2 and an outgassing gas 4 is disposed on the upper side of the converter body 2 toward the upper surface of the molten metal 5. [ The upper lance 3 is disposed. The tuyer 4 and the upper lance 3 transversely and transpose oxygen (O ₂ ), and thus the decarburization reaction of the molten manganese iron melt 5 proceeds.

Generally, oxygen (O ₂ ) is supplied through the upper lance 3 and mixed gas of oxygen (O ₂ ) and nitrogen (N ₂ ) or oxygen (O ₂ ) and argon Ar) is supplied. The molten manganese-base alloyed molten metal 5 accommodated in the converter body 2 is properly flowed by the cutting and crossing work, and the carbon (C) in the molten metal 5 is removed by the supplied oxygen.

When the low-carbon manganese-based alloy iron is manufactured using the above-described converter apparatus 1, the following technical difficulties exist. Since the upper lance 3 continuously supplies oxygen (O ₂ ) to perform the decarburization operation, an evaporation loss of manganese (Mn) due to excessive oxygen (O ₂ ) blowing occurs in the latter half of the refining operation. In addition, a sudden temperature rise occurs due to the oxidation reaction at a portion where the oxygen (O ₂ ) supplied from the upper lance 3 and the upper surface of the molten metal 5 directly contact each other. The vapor pressure of manganese (Mn) is increased due to the rapid temperature rise of the upper surface of the molten metal (5), and evaporation of manganese (Mn) is triggered. Therefore, the refined manganese-based alloy iron has a problem that the content of manganese (Mn) is lowered and the rate of realization is lowered. Since the evaporation loss of manganese (Mn) inevitably occurs in the refining work, production of manganese-based alloy iron containing manganese (Mn) exceeding a certain content becomes difficult when supply and demand of high-quality manganese ore become unstable. Therefore, there is a difficulty that it becomes difficult to meet the demand of the consumer in case of unstable supply and demand of high-quality manganese ore. Further, when the flow rate of oxygen (O ₂ ) supplied from the upper lance 3 is decreased in order to minimize manganese (Mn) loss in the refining process, the agitating force of the molten metal 5 is weakened, There is a problem.

FIG. 2 is a schematic view of an apparatus for manufacturing low-carbon manganese-based alloyed iron using the composite iron scouring of the present invention, and FIG. 3 is a schematic view of a method for manufacturing low- Fig. FIGS. 4 and 5 are views schematically showing driving of a low carbon manganese-based alloy iron manufacturing apparatus using the composite iron scouring of the present invention. 7 is a view schematically showing the diffuser member of the present invention.

2, an apparatus 10 for manufacturing a low-carbon manganese-based alloy iron using composite iron scouring comprises a converter body 100 in which a space 110 is formed to accommodate a molten metal 5, A tuyer unit 200 arranged on the side wall and capable of horizontally transversely transversely injecting gas in the interior of the molten metal 5 accommodated in the space 110, a lance unit 300 capable of taking in the outflow gas toward the upper surface of the molten metal 5 And a control unit 400 connected to the lance unit 300 to control the mixing ratio of the offgas and the supply amount of the offgas.

The lance unit 300 includes an oxygen supply pipe 310 to which oxygen (O ₂ ) is supplied and an inert gas supply pipe 320 to supply an inert gas to the oxygen supply pipe 310. An oxygen valve member 315 and an inert gas valve member 325 are disposed on the oxygen supply pipe 310 and the inert gas supply pipe 320 so that the amount of oxygen (O ₂ ) and the amount of inert gas in the offgas gas are adjusted . The tuyer unit 200 also includes an oxygen supply pipe 210 and an inert gas supply pipe 220 to which oxygen (O ₂ ) is supplied. An oxygen valve member 215 and an inert gas valve member 225 are disposed on the oxygen supply pipe 210 and the inert gas supply pipe 220 so that the amount of oxygen (O ₂ ) and the amount of inert gas in the entrained gas are adjusted . The control unit 400 is electrically connected to the oxygen valve members 215 and 315 and the inert gas valve members 225 and 325 to control them. The inert gas to be supplied to the offgas gas and the interleaved gas may be, but not limited to, argon gas (Ar) or nitrogen gas (N ₂ ).

7, the diffuser member 300 is connected to the tip of the inert gas supply pipe 320, and the diffuser member 330 is disposed inside the oxygen supply pipe 310. As shown in FIG. A plurality of injection holes 335 are formed in the diffuser member 330 and an inert gas is supplied into the oxygen supply pipe 310 through the injection holes 335. The inert gas and oxygen (O ₂ ) are mixed by the diffuser member 330 to form a turbulent flow, and the offgas formed by the turbulent flow is introduced through the lance unit 300.

Sangchwi gas is separated by the second gas sangchwi sangchwi consisting of a first gas and the oxygen (O ₂₎ and a mixed gas of an inert gas consisting of oxygen (O _2). The control unit 400 controls the lance unit 300 which superposes the first offgas toward the molten metal 5 charged in the converter main body 100 such that the second offgas gas is taken as a critical critical point of the carbon. The composition of the low-carbon manganese-based alloy steel manufacturing apparatus 10 using the composite iron scouring of the present invention has been described with reference to the drawings. In the method of manufacturing low-carbon manganese iron-based iron using the following composite iron scouring, Detailed operation of the low-carbon manganese-based alloy iron manufacturing apparatus will be described in detail.

3, the method for manufacturing low-carbon manganese-based alloyed iron according to an embodiment of the present invention includes a loading step S10, a first decarburization step S20, a second decarburization step S30, and a tapping step S40 ).

In the charging step S10, the molten metal 5 of high carbon manganese based alloy iron is charged into the space 110 formed in the converter main body 100. In the first decarburization step S20, off-gas is introduced into the upper surface of the molten metal 5 through the lance unit 300, and the molten metal is injected into the lower side of the molten metal 5 through the tuyer unit 200 in the lateral direction The transverse gas is transversally blown. First, because the decarburization inert gas valve member (325) in step (S20) is closed and keep the open oxygen valve member 315, the lance unit 300 is a first sangchwi gas consisting of oxygen (O ₂₎ And is superimposed on the upper surface of the molten metal. The tuyere unit 200 transverses the first entangled gas mixed with the oxygen (O ₂ ) and the inert gas in the first decarburization step (S20). The operation of the apparatus 10 for producing low-manganese-base alloyed iron using the composite iron scouring in the first decarburization step S20 is shown in Fig.

FIG. 6 is a graph showing the decarburization rate (dW _C / dt) and demagnetization rate (dW _Mn / dt).

As shown in FIG. 6, the decarburization process of the manganese-based alloy iron can be divided into three sections. The initial period of decarburization is the process of raising the temperature to the temperature required for the decarburization reaction, and the second period of decarburization is the period where the decarburization reaction is active. In decanter 2, maximizing the oxygen (O ₂ ) transport rate is a major factor in increasing decarburization efficiency. As the decarburization reaction progresses, the carbon content in the coal 5 decreases. When the carbon content reaches a certain level, the decarburization rate decreases even when the oxygen (O ₂ ) transport rate is maximized. This is called the carbon critical point, and the carbon content at this time is called the carbon critical content.

The carbon critical point is derived using the derivative of the decarburization rate. The decarburization rate (V _C ) is shown in the following equation (2), and the differential value of the decarburization rate (V _C ) is shown in the following equation (3).

<Formula 2>

V _C = d (Wc) / dt

In the formula 2, Wc means the weight of carbon in the molten metal.

<Formula 3>

d (Vc) / dt = d 2 (Wc) / dt 2

Referring to FIG. 6 and FIG. 3, the carbon critical point means a point at which the differential value of the decarburization rate changes from 0 to a negative value, which is indicated by C in FIG.

The second decarburization step (S30) proceeds from the carbon critical point, and the control unit (400) controls to open the inert gas valve member (325). That is, as the inert gas valve member 325 is opened, a second offgas gas composed of a mixed gas of oxygen (O ₂ ) and an inert gas is introduced toward the upper surface of the molten metal 5. The operation of the apparatus 10 for producing low-manganese-base alloyed iron using the combined iron scouring of the second decarburization step S20 is shown in Fig.

The controller 400 controls to open the inert gas valve member 325 and controls the oxygen valve member 315 to be partially closed so that the flow rate of the second offgas gas maintains the flow rate of the first offgas. Since the second decarburization step (S30) in the from point of the subsequent carbon threshold blowing only oxygen (O ₂₎ amount required for residual carbon decarburization of the molten metal 5, and reduced oxygen (O ₂₎ blowing a mixture with an inert gas by an amount, The vapor pressure of manganese can be lowered and the supply of excess oxygen (O ₂ ) can be suppressed, thereby effectively reducing the manganese evaporation loss. Further, since the off-set flow rate is maintained at the maximum, and the stirring force of the molten metal 5 is increased, the decarburization efficiency can be effectively increased.

For the decarburization efficiency and prevention of the loss of manganese, the off-set flow rate is preferably 2000 to 2400 Nm ³ / hr, and more preferably 2200 Nm ³ / hr. A second flow rate of the gas hoengchwi the decarburization step (S30) is preferred in terms of the stirring force of molten metal (5) remains at 100 ~ 300 Nm ³ / hr level.

The amount of oxygen (O ₂ ) supplied to the interior of the converter body 100 through the lance unit 300 and the tuyer unit 200 in the second decarburization step S30 is calculated by the following equation (1).

<Formula 1>

W _O = {(W _CT -W _CC ) / 12} * 16 / E _O

In Equation 1, W _O is the oxygen demand (g), W _CT is the total carbon content (g) contained in the molten metal, W _CC is the amount of carbon removed to the carbon threshold (g), and E _O is the oxygen efficiency. The oxygen efficiency (E _O ) is a constant in consideration of process efficiency and is a constant selected from 0.75 to 0.85.

Second decarburization step (S30) in the second gas and the second sangchwi hoengchwi gas is supplied according to the oxygen demand (W _O) to be calculated by the expression (1). That is, the control unit 400 controls the oxygen valve unit 300 so that the amount of oxygen (O ₂ ) supplied by the lance unit 300 and the tuyer unit 200 in the second degassing step S30 satisfies the oxygen demand W _O , (215, 315) and inert gas valve members (225, 325).

The partial pressure of CO gas in the burner main body 100 during the refining operation can be derived from the following Equation 4.

<Formula 4>

P _CO = wt% CO / (wt% Ar + wt% CO)

Since the second offgas mixture in which oxygen (O ₂ ) and argon (Ar) are mixed is introduced in the second decarburization step (S30), the partial pressure of CO gas is lower than that in the case where only oxygen (O ₂ ) is taken up. In the case of superimposing only oxygen (O ₂ ), P _CO is in the range of 0.949 to 0.929, whereas in the present invention, in which oxygen (O ₂ ) and argon (Ar) are mixed, P _CO is in the range of 0.550 to 0.778 .

Equation 8 below is derived from Equation 5 to Equation 7, and the decarburization temperature according to P _CO can be derived using Equation 8.

&Lt; EMI ID =

MnO = Mn + 1/2 O ₂ ? G? (Cal) = 97683-21.317T

(+) C + 1 / 2O ₂  = CO (+)? G? (Cal) = -27108 - 20.576T

 MnO + C = Mn + CO? G? (Cal) = 70575 - 41.893T

&Lt; EMI ID =

K = (a _Mn * P _CO ) / (a _MnO * a _C )

a _MnO = 1 (MnO = pure)

∴ K = (a _Mn * P _CO ) / a _C

Equation (7)

? G? (Cal) = - RTlnK, (R = 1.987 cal / K)

lnK = - (? G / (1.987 * T))

∴ K = exp (- (ΔG ° / (1.987 * T)))

<Formula 8>

(aMn * PCO) / aC = exp (- (?? G / (1.987 * T)))

In the case of superabsorbing using only oxygen (O ₂ ), the decarburization reaction occurs at about 1754 to 1806 ° C. on the basis of 0.5 wt% C, but when the oxygen (O ₂ ) and argon (Ar) C decarbonation occurs at about 1733-1749 ° C. Accordingly, when oxygen (O ₂ ) and argon gas (Ar) are mixed to be superimposed on each other, P _CO decreases in the refining process to lower the decarburization temperature, thereby reducing the oxidation loss of manganese.

In the second decarburization step (S30), the second offgas gas is formed by turbulent flow by the diffuser member (330). This is because oxygen (O 2) and inert gas are completely mixed and superposed, and the Raynold number of the second offgas is preferably 2100 or more. When the Reynold's number is maintained at 2100 or more, the decarburization efficiency of the molten metal 5 is maximized. Reynolds number can be calculated by Equation 9 below turbulent flow.

Equation (9)

Re = (D *? *?) /?

Where D is the characteristic length, v is the average velocity of the fluid, ρ is the density of the fluid, and η is the viscosity of the fluid. do.

In the tapping step S40, the decarbonized low-manganese-based alloy iron-containing molten metal 5 is spouted, thereby completing the manufacturing method of low-carbon manganese ferrofins using the composite iron scouring according to an embodiment of the present invention.

<Examples>

The low carbon manganese based alloy iron according to one embodiment of the present invention was produced using the converter body 100 having a capacity of 20 tons. First, high carbon manganese based ferroalloy steel 5 was charged into a converter, oxygen (O ₂ ) was introduced into the lance unit 300, oxygen (O ₂ ) and argon (Ar) were introduced into the tubular unit 200 And mixed. The tuyer unit 200 uses a _double pipe crossflow tuyer unit 200 located 350 mm above the bottom of the inside of the converter body 100. Oxygen (O ₂ ) and argon gas (Ar) Experiments were carried out by blowing argon gas (Ar) as the external appearance.

The initial flow rate of oxygen (O ₂ ) from the lance unit 300 was maintained at a maximum and the distance between the tip of the lance 300 and the surface of the melt 5 was set at 1000 to 1200 mm. Only oxygen (O ₂ ) necessary to oxidize the remaining carbon from the carbon critical point was taken in and the argon gas (Ar) was injected by the decreasing oxygen (O ₂ ) flow rate to maintain the maximum flow rate. In this test example, the offgas gas is mixed with oxygen (O ₂ ) and argon (Ar) gas, but nitrogen gas (N ₂ ) may be used instead of argon gas (Ar). In the second decarburization step (S40) sangchwi gas is oxygen (O _2): 1.5 were mixed so that: the ratio of the argon gas (Ar) 1: 0.05 ~ 1 . The off-set flow rate was 2200 Nm ³ / hr before and after the carbon critical point, and the transverse flow rate was maintained at 100-300 Nm ³ / hr. Table 1 below is an oxygen (O ₂₎ in accordance with one embodiment of the high taking the only oxygen (O ₂₎ in sangchwi gas from carbon-manganese-based alloys of iron and low-carbon manganese-based ferroalloy a comparative example matter content produced the present invention And the argon gas (Ar) were mixed in a turbulent flow to obtain low-carbon manganese-based alloy iron from the high-carbon manganese-based alloy iron. In Table 2, This is a table comparing the amount of high-carbon-manganese-based alloyed iron required to produce one ton of iron-based alloys.

division Mn Si C S N O Fe Etc. Comparative Example
(wt%) High carbon manganese based alloy iron 80.78 0.13 7.02 0.00 0.02 0.29 11.17 0.60 Low carbon manganese based alloy iron 80.91 0.28 0.45 0.01 0.04 0.76 15.78 1.88 Example
(wt%) High carbon manganese based alloy iron 77.75 0.17 6.24 0.00 0.01 0.30 13.95 1.58 Low carbon manganese based alloy iron 77.93 0.43 0.48 0.00 0.04 1.25 18.69 1.18

division Weight (kg) High carbon (kg) /
Low Carbon (kg) Mn recovery (%) Comparative Example High carbon manganese based alloy iron 15,040 1.407 71.26 Low carbon manganese based alloy iron 10,690 Example High carbon manganese based alloy iron 14,480 1.338 74.96 Low carbon manganese based alloy iron 10,820

As shown in Table 2, in the comparative example, the high-carbon manganese-based alloy iron necessary for producing one ton of low-carbon manganese-based alloyed iron is 1.407 tons, and in the case of the embodiment, necessary for producing one ton of low- And the high carbon manganese-based alloy iron is 1.338 tons. In other words, it can be confirmed that the cost saving effect is about 4.9% in producing the same amount of low-carbon manganese-based alloy iron. In addition, the Mn recovery rate of the Examples is about 3% or more as compared with the Comparative Example, and it can be confirmed that the manganese loss rate is remarkably reduced.

Although the present invention has been described in detail by way of examples, other forms of embodiments are possible. Therefore, the technical idea and scope of the claims set forth below are not limited to the embodiments.

1: Converter device 2, 100: Converter body
3: upper lance 4:
5: molten metal 6, 110: space
10: Low carbon manganese based alloy steel manufacturing apparatus 200: Tire unit
300: lance unit 310: oxygen supply pipe
315: oxygen valve member 320: inert gas supply pipe
325: inert gas valve member 330: diffuser member
335: injection hole 400: control unit

Claims (15)

A charging step of charging the high carbon manganese based alloy steel molten steel into the converter body;
And a first decarburization gas containing a first transverse gas of a mixed gas of oxygen and an inert gas in a transverse direction inside the molten steel, step; And
A second offgas gas composed of a mixed gas of oxygen and an inert gas from a carbon critical point is directed toward the upper surface of the molten steel, the second offgas gas is maintained while maintaining a predetermined offgas flow rate of the first offgas, And a second decarburization step of horizontally transversely taking in a second intercepting gas composed of a mixed gas of inert gas and inert gas in the molten steel,
The carbon critical point is a point at which the differential value of the molten steel decarburization rate is converted to a negative value,
Wherein the second decarburization phase, blowing a second gas and the second sangchwi hoengchwi gas according to the oxygen demand (W _O) to be calculated by the equation 1 below,
And the decarburization temperature of the second decarburization step is controlled to 1733 to 1749 ° C.
<Formula 1>
W _O = {(W _CT -W _CC ) / 12} * 16 / E _O
In Equation 1, W _O is the oxygen demand (g), W _CT is the total carbon content (g) contained in the molten metal, W _CC is the amount of carbon removed to the carbon threshold (g), and E _O is the oxygen efficiency. The method according to claim 1,
Wherein the oxygen efficiency E ₀ of the formula 1 is 0.75-0.85. The method according to claim 1,
Wherein the inert gas is any one selected from the group consisting of argon gas (Ar) and nitrogen gas (N ₂ ). The method according to claim 1 or 3,
Wherein the second offgas gas has a mixing ratio of oxygen to an inert gas of 1: 0.05 to 1.5. The method according to claim 1 or 3,
Wherein the second offgas is formed as a turbulent flow, and the second offgas is formed as a turbulent flow. delete The method according to claim 1,
Wherein the flow rate of the first and second offgas is 2000 to 2400 Nm ³ / hr. delete delete delete delete delete delete delete delete

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