WO2015122602A1 - Mold flux, continuous casting method using same, and slab manufactured using same - Google Patents

Mold flux, continuous casting method using same, and slab manufactured using same Download PDF

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Publication number
WO2015122602A1
WO2015122602A1 PCT/KR2014/011349 KR2014011349W WO2015122602A1 WO 2015122602 A1 WO2015122602 A1 WO 2015122602A1 KR 2014011349 W KR2014011349 W KR 2014011349W WO 2015122602 A1 WO2015122602 A1 WO 2015122602A1
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WIPO (PCT)
Prior art keywords
mold flux
mold
flux
continuous casting
molten steel
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PCT/KR2014/011349
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French (fr)
Korean (ko)
Inventor
한상우
정태인
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주식회사 포스코
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Publication of WO2015122602A1 publication Critical patent/WO2015122602A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/111—Treating the molten metal by using protecting powders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/08—Accessories for starting the casting procedure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal

Definitions

  • the present invention relates to a mold flux, a continuous casting method using the same, and a cast manufactured using the same, and more particularly, to a mold flux capable of suppressing defects of the cast, a continuous casting method using the same, and a cast manufactured using the same. It is about.
  • the cast steel is produced while the molten steel contained in the mold is cooled through the cooling table.
  • the continuous casting process injects molten steel into a mold having a constant internal shape, and continuously draws the reacted slabs into the lower side of the mold to produce semi-finished products of various shapes such as slabs, blooms, billets, beam blanks, and the like. It is a process.
  • the cast steel is first cooled in the mold, and after passing through the mold, solidification proceeds through a process in which water is injected into the cast steel and secondly cooled.
  • Primary cooling occurring in the mold is greatly affected by the flow of molten steel in the mold, the melting behavior of the mold flux, and the ability to uniformly penetrate between the mold and the slab.
  • the cast produced by the casting process is caused by a variety of causes, such defects may occur due to the flow of molten steel in the mold, the load by the roll during the casting, the load by drawing.
  • defects caused by molten steel flow are mostly in the form of inclusions and slag, but defects caused by loads due to rolls and loads during drawing are mainly generated as cracks on the surface of the cast steel. Cracks formed in the mold may occur during the primary cooling of the molten steel in the mold.
  • nickel is an expensive alloying element, which increases production costs and fluctuates the solidification behavior of steel.
  • the steel is cast as alpha ferrite ( ⁇ ( ⁇ )) at a temperature of 1400 ° C. or higher in a low carbon region to exhibit stable solidification behavior.
  • ⁇ ( ⁇ ) alpha ferrite
  • FIG. 2 when the nickel content is less than 3% by weight, the gamma austenite ( ⁇ -Fe) range is widened so that the apolytic reaction in which the liquid phase and the delta phase are transformed into the delta phase and the gamma phase (that is, at or below the temperature of the crystallization). Fluctuations, ie the solidification behavior of the steel, can change.
  • the cast steel produced by such a reaction promotes uneven coagulation in the mold due to severe coagulation shrinkage, thereby forming an uneven structure on the surface of the cast steel, resulting in surface cracking and the like. There is a problem that causes.
  • the present invention provides a mold flux that can suppress or prevent defects formed in the cast steel to improve process efficiency and productivity, a continuous casting method using the same, and a cast steel manufactured using the same.
  • the present invention provides a mold flux, a continuous casting method using the same and the cast produced using the same can reduce the production cost of raw materials.
  • the first mold flux comprising SiO 2 , CaO, Na 2 O, Al 2 O 3 and CaF; And a second mold flux including a metal-containing material containing at least one of metals having lower oxygen affinity than aluminum (Al).
  • the second mold flux may include at least one metal-containing material of nickel (Ni), manganese (Mn), zinc (Zn), and titanium (Ti).
  • the specific gravity of the melt of the second mold flux may be lower than the specific gravity of the molten steel to be introduced and may have a higher range than the specific gravity of the melt of the first mold flux.
  • the second mold flux may include at least one of a metal oxide and a metal powder.
  • the content of the second mold flux may be in a range of 5 to 50 wt% based on the total weight of the first and second mold fluxes.
  • the continuous casting method according to the embodiment of the present invention is a continuous casting method for manufacturing molten steel by supplying molten steel to a mold, the article comprising SiO 2 , CaO, Na 2 O, Al 2 O 3 and CaF on the molten steel
  • the first mold flux and a second mold flux comprising a metal-containing material containing at least any one of Ni, Mn, Zn and Ti among the metals having a lower oxygen affinity than Al is supplied to at least a portion of the surface of the cast steel. It is characterized by forming a coating layer by a two-mold flux.
  • the molten steel may include 0.1 to 3.5% by weight of copper.
  • the first mold flux may be continuously supplied from the beginning to the end of the casting.
  • the supply of the second mold flux may include supplying the second mold plug intermittently in response to fluctuations in the surface of the molten steel in the mold.
  • the second mold flux may be supplied when the melt surface fluctuation frequency of the molten steel in the mold is 0.01 to 0.25 Hz.
  • the content of the second mold flux may be in the range of 5 to 50 wt% based on the total weight of the first and second mold fluxes.
  • the first mold flux may be supplied to a center region of the mold, and the second mold flux may be supplied to an region adjacent to an inner wall of the mold.
  • the second mold flux may be supplied to an area within 50 mm from the inner wall of the mold.
  • the cast steel according to the embodiment of the present invention is characterized in that a coating layer including a metal-containing material containing at least one of metals having lower oxygen affinity than aluminum (Al) is formed on at least a part of the surface.
  • the metal-containing material may be at least one of Ni, Mn, Zn, and Ti among metals having lower oxygen affinity than Al.
  • the continuous casting method using the same, and the cast manufactured using the same it is possible to suppress or prevent defects such as cracks formed in the cast by controlling the solidification behavior of the surface of the cast.
  • the mold flux becomes liquid slag by the heat of the molten steel and then flows between the slab and the mold.
  • the mold flux introduced between the cast and the mold plays an important role in solidifying the cast.
  • Ni, Mn, Zn, Ti, and Cr which have a lower oxygen affinity than Al in the liquid slag, are distributed to the metal-containing material particles.
  • the radiant heat can be scattered and transmitted uniformly and stably to the cast steel. This allows the cast to solidify uniformly and to improve the surface quality of the cast.
  • elements such as Ni, Mn, Zn, Ti, and Cr in the mold flux are concentrated on the surface during initial solidification of the cast, so that the formation of cracks due to solidification non-uniformity is controlled by controlling the solidification behavior of the steel so that superstable reactions with low solidification shrinkage occur. Can be reduced.
  • liquid copper is prevented from flowing out to the surface portion of the cast to form a concentrated layer, causing grain boundary cracks due to copper having a low oxygen affinity. Can be suppressed or prevented.
  • a thickening layer (coating layer) of a metal-containing material having a lower oxygen affinity for example, a lower oxygen affinity than Al, may be selectively formed on the surface of the cast steel, thereby suppressing an increase in production cost due to the use of an expensive metal-containing material. can do.
  • FIG. 2 is a view showing a change in Fe-C state diagram when Ni is added to molten steel.
  • FIG 3 is a cross-sectional view and a schematic view of the cast steel produced by the continuous casting method according to an embodiment of the present invention.
  • FIG. 4 is a view schematically showing a continuous casting device for explaining the continuous casting method according to an embodiment of the present invention.
  • FIG. 5 is an oxygen affinity graph for explaining a metal-containing material forming a mold flux according to an embodiment of the present invention.
  • Figure 6 is a view showing the experimental results for the component control of the mold flux according to an embodiment of the present invention.
  • FIG. 7 is a view for explaining the timing of the injection of the mold flux containing the metal-containing material in the continuous casting method according to an embodiment of the present invention.
  • Figure 8 is a photograph and a schematic view comparing the cast produced in the continuous casting method according to the embodiment of the present invention and the continuous casting method according to the prior art.
  • FIG. 9 is a schematic diagram showing a state of the cast steel produced according to an embodiment of the present invention.
  • Figure 4 is a view showing a continuous casting apparatus for explaining the continuous casting method according to an embodiment of the present invention.
  • the slab 100 manufactured by the continuous casting method according to an embodiment of the present invention is provided with a coating layer 200 on the surface.
  • the coating layer 200 may be formed on the surface of the cast steel 100 in the continuous casting process, and more specifically, may be formed by the mold flux supplied to the mold in the continuous casting process.
  • the coating layer is formed to include a metal-containing material of at least one of nickel (Ni), manganese (Mn), zinc (Zn), and titanium (Ti), which has a lower oxygen affinity than aluminum (Al), so that the copper component and The surface defect which arises by the solidification behavior of molten steel can be suppressed.
  • the metal-containing material contained in the coating layer can increase the solubility of copper in the cast steel, and the superstable reaction in which the liquid phase and the delta phase transform into a gamma phase and a liquid phase on the surface of the cast steel on which the coating layer is formed causes a solidification shrinkage of the cast steel. It can reduce, and the phenomenon which a crack generate
  • the continuous casting apparatus includes a mold 10, an immersion nozzle 20 for supplying molten steel S to the mold 10, and a mold flux supply device 30, 32 for supplying mold flux to the mold 10. can do.
  • it may include a sensor (not shown) for measuring the change in the surface of the molten steel in the mold 10, and a controller (not shown) for controlling the operation of the mold flux supply apparatus according to the change in the surface of the molten steel measured by the sensor.
  • the structure of the mold 10 and the immersion nozzle 20 is the same as that of a known continuous casting apparatus, and thus a detailed description thereof will be omitted.
  • the mold flux supply devices 30 and 32 are provided on the mold 10 to supply the first mold flux P1 to the central region of the mold 10 adjacent to the immersion nozzle 20.
  • a second mold flux feeder 32 for supplying the second mold flux P2 to the edge region adjacent to the wall of the mold 10.
  • the second mold flux supplier 32 may be formed to supply the second mold flux P2 to a region within 50 mm from the wall of the mold 10. This is to efficiently penetrate the second mold flux P2 between the molten steel and the mold, and even if the second mold flux P2 is supplied over a wider range than the indicated range, the supply amount of the second mold flux P2 and the cast surface
  • the thickness of the coating layer formed in the is not proportional.
  • the amount of the expensive metal-containing material forming the second mold flux P2 increases by increasing the amount of the second mold flux P2. The saving effect is reduced.
  • the first mold flux P1 includes SiO 2 , CaO, Na 2 O, Al 2 O 3 , CaF, and the like, and the second mold flux P2 has a lower oxygen affinity, for example, a lower oxygen affinity than aluminum.
  • Metal including at least one of nickel, manganese, zinc and titanium.
  • the second mold flux P2 may be supplied to the mold in the form of a metal oxide, or may be supplied to the mold 10 in the form of a metal powder.
  • the sensor measures a change in the surface of the molten steel in the mold 10 on the mold 10, and transmits the measurement result to the controller.
  • the sensor measures the period of fluctuation of the surface of molten steel that occurs according to the solidification behavior of the molten steel, and a magnetic field displacement sensor may be used, for example.
  • the sensor is not limited thereto, and various types of sensors may be used.
  • the controller controls the operation of the first mold flux feeder 30 and the second mold flux feeder 32 in accordance with the results measured at the sensor, and supplies the first mold flux and the second mold flux into the mold 10.
  • the controller may intermittently operate the second mold flux feeder 32 according to the type of molten steel to supply the second mold flux to the mold 10.
  • the coating layer may be formed on at least part of the surface of the slab by supplying the first mold flux P1 and the second mold flux P2 to the mold 10 in the continuous casting process.
  • FIG. 5 is an oxygen affinity graph for explaining a metal-containing material forming a mold flux according to an embodiment of the present invention
  • Figure 6 is a view showing the experimental results for the component control of the mold flux according to an embodiment of the present invention.
  • 7 is a view for explaining the timing of the injection of the mold flux containing the metal-containing material in the continuous casting method according to an embodiment of the present invention.
  • the metal-containing material may be at least one of Ni, Mn, Zn, and Ti among metals having lower oxygen affinity than Al.
  • the second mold flux may include a metal containing material having a lower oxygen affinity, such as a lower oxygen affinity than aluminum (Al).
  • metal-containing materials having lower oxygen affinity than aluminum include titanium, silicon (Si), manganese (Mn), zinc (Zn), nickel (Ni), and the like, wherein silicon has welding properties. Since it lowers, it is not suitable for this invention.
  • Nickel among the metal-containing materials that can be used in the present invention can implement the effect of improving the solubility of copper in the cast steel, the remaining metal-containing materials can implement the effect of controlling the solidification behavior of the cast steel.
  • the metal-containing material may be used in the form of an oxide such as TiO 2 , MnO, ZnO, NiO, or the like, or may be used in the form of a metal powder. Since the metal-containing material has a low oxygen affinity, the metal-containing material hardly interacts with the first mold flux used in oxide form such as SiO 2 , CaO, Na 2 O, or the like. Therefore, the first mold flux and the second mold flux may be supplied into the mold and then melted to maintain a constant state. However, in the case of using a metal-containing material in the form of oxide, since molten steel is almost free of oxygen, it is reduced by reaction with calcium (Ca), aluminum (Al), silicon (Si), iron (Fe), etc.
  • the melt of the second mold flux may have a specific gravity lower than that of the molten steel and higher than that of the melt of the first mold flux. Accordingly, the melt of the second mold flux may be stably positioned between the melt of the first mold flux and the molten steel and may be efficiently introduced between the solidification cell of the molten steel and the mold by the vibration applied to the mold during continuous casting.
  • the mold flux according to the embodiment of the present invention includes a first mold flux used in a general continuous casting process and a second mold flux containing a metal-containing material.
  • the second mold flux may be used in an amount of 5 to 50% by weight, preferably 10 to 30% by weight, based on the total weight of the first mold flux and the second mold flux.
  • the first mold flux may contain 13-30 wt% SiO 2 , 15-40% CaO, 2-10 wt% Al 2 O 3 , Na 2 O and CaF
  • the second mold flux may contain 5-5 NiO. It may include 50% by weight.
  • the amount of the second mold flux may be used up to 50% by weight depending on the amount of Na 2 O flux.
  • FIG. 6 (a) is a photograph of a cast steel obtained by observing the concentration of Ni at the reaction interface after the reaction between NiO and molten steel according to the content of NiO in the second mold flux through an electronic component analyzer (EPMA).
  • EPMA electronic component analyzer
  • the penetration depth of Ni becomes deeper as the content of NiO in the second mold flux increases. That is, it can be seen that when the content of NiO in the second mold flux is 5% by weight, a thin coating layer is formed on the surface of the cast steel.
  • the content of NiO in the second mold flux increases to 10% by weight, 15% by weight and 20% by weight, it was found that Ni penetrated into the slab from the surface of the slab to increase the concentration of Ni and the thickness of the coating layer. . Therefore, when the content of NiO in the second mold flux is at least 5% by weight, it can be seen that a coating layer can be formed on the surface of the cast steel.
  • the amount of the second mold flux is increased, Ni penetrates to the predetermined depth from the surface of the cast steel so that it is relatively wide. It can be seen that the thickness of the coating layer increases by being formed over the area.
  • FIG. 6B is a photograph that simulates the melting characteristics of the second mold flux during casting.
  • the picture on the left is for measuring the basic properties of the second mold flux, which is initially made into a rectangular shape, but the shape is deformed into Sintering-Softening-Sphere-1 / 2 sphere-Fusion form as time passes. .
  • a specimen that appears in its initial form using a second mold flux containing NiO was prepared, and then heated to about 1300 ° C. to measure a molten state.
  • the photo shown on the right in Figure 6 (b) shows the melt state of the specimen according to the content of NiO.
  • the content of NiO is increased by 10% by weight in the range of 30% by weight to 80% by weight, it can be seen that the specimen is melted to some extent up to 50% by weight, but in the range of 60% by weight to 80% by weight It can be seen that melting of the two mold flux hardly occurs.
  • the second mold flux is suitably used in the range of 5% by weight to 50% by weight, the second molten flux may be melted in the mold, changed into a liquid slag form, and then flows between the mold and the slab to form a coating layer on the surface of the slab. .
  • the second mold flux may be selectively supplied according to the type of molten steel used for casting the cast steel, for example, the content of copper.
  • the first mold flux may be continuously supplied from the beginning of the casting, the second mold flux may be selectively supplied when there is a fluctuation in the surface according to the solidification behavior of the cast.
  • Figure 7 shows the result of measuring the fluctuation of the molten steel of the molten steel using a sensor in the process of casting the cast.
  • the frequency magnitude increases rapidly in a specific region.
  • FFT fast fourier transform
  • the first mold flux and the second mold flux can be continuously supplied from the beginning to the end of the casting.
  • the steel containing copper may concentrate on the surface of the cast steel in the molten steel, which may cause cracks on the surface of the cast steel, thereby continuously supplying the second mold flux during the casting process, thereby forming a coating layer over the surface of the cast steel.
  • a coating layer is formed on the surface of the cast steel by the second mold flux, thereby suppressing surface defects of the cast steel due to the grain boundary penetration of copper.
  • the coating layer is formed on the surface of the slab using a metal-containing material by the second mold flux, the solidification behavior of the slab is stabilized even with a smaller amount than when a metal-containing material such as nickel (Ni) is added to molten steel.
  • a metal-containing material such as nickel (Ni) is added to molten steel.
  • the grain boundary penetration of copper can be suppressed.
  • it is possible to easily form a coating layer on the surface of the cast during the continuous casting process without a separate additional process there is no problem such as cost increase due to the increase in equipment or decrease in production amount due to the increase in production time.
  • Figure 8 is a photograph and a schematic view comparing the cast steel produced by the continuous casting method according to the embodiment of the present invention and the continuous casting method according to the prior art
  • Figure 9 is a schematic diagram showing the state of the cast steel produced according to an embodiment of the present invention. to be.
  • the cast steel was manufactured using a mold flux (second mold flux) to which 20 wt% NiO was added.
  • the steel grade was 0.35 wt% copper, and the representative components were 0.1 wt% carbon and 0.3 wt% Si. %, Mn 1.5 weight%, Ni 0.02 weight%, Ti 0.03 weight%.
  • nickel (Ni) contained in the steel is contained due to contamination by alloy iron, but very low content by other ferroalloy, but Ni must be 1.5 ⁇ 2 times or more compared to copper in order to achieve the effect of Ni The effect can be ignored.
  • the cast was cast while supplying only the initial mold mold flux, for example, the first mold flux. Thereafter, as shown in FIG. 7, the cast was cast while the second mold flux containing 20% by weight of NiO was added together with the first mold flux at the time when the fluctuation of the water surface occurred as shown in FIG. 7.
  • the components in the slab were measured through an electronic component analysis method EPMA (Electron Probe Micro-Analysis).
  • EPMA Electro Probe Micro-Analysis
  • the upper left (CP) is the initial shape of the cast
  • the upper right (Cu) is the position of the copper (Cu) component in the slab
  • the lower left (Ni) is the position of nickel (Ni) in the cast
  • right The lower end Fe represents the position of the iron component. Looking at this, it can be seen that a high concentration of Ni layer (coating layer) is formed on the surface of the cast steel cast using the mold flux (Ni 2nd flux) containing NiO.
  • Cu existing in molten steel may be selectively oxidized (a phenomenon in which Cu remains on the surface of the cast steel when the Fe contacts with external oxygen). Since it does not penetrate to, it is possible to suppress the occurrence of cracks on the surface of the cast steel.
  • the mold flux according to the present invention and the continuous casting method using the same can facilitate securing the weldability and low temperature toughness of marine structural steel by controlling the solidification behavior of the surface of the cast steel to suppress or prevent defects such as cracks formed in the cast steel.

Abstract

The present invention relates to a mold flux, a continuous casting method using the same, and a slab manufactured using the same. The continuous casting method of manufacturing a slab by feeding molten steel into a mold comprises: feeding a first mold flux and a second mold flux into the upper portion of the molten steel, wherein the first mold flux includes SiO2, CaO, Na2O, Al2O3, and CaF, and the second mold flux includes metal-containing material containing at least one of Ni, Mn, Zn, and Ti among metals having a lower oxygen affinity than Al; and forming a coating layer by the second mold flux on at least a portion of a surface of a slab. Therefore, it is possible to control the solidification behavior of a slab and suppress the defect of the slab by preventing the inter-granular penetration of a copper component.

Description

몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편Mold flux, continuous casting method using the same, and cast steel manufactured using the same
본 발명은 몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편에 관한 것으로서, 더욱 상세하게는 주편의 결함을 억제할 수 있는 몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편에 관한 것이다. The present invention relates to a mold flux, a continuous casting method using the same, and a cast manufactured using the same, and more particularly, to a mold flux capable of suppressing defects of the cast, a continuous casting method using the same, and a cast manufactured using the same. It is about.
일반적으로, 주편은 주형에 수용된 용강이 냉각대를 거쳐 냉각되면서 제조된다. 예컨대, 연속주조공정은 일정한 내부 형상을 갖는 주형에 용강을 주입하고, 주형 내에서 반응고된 주편을 연속적으로 주형의 하측으로 인발하여 슬라브, 블룸, 빌렛, 빔 블랭크 등과 같은 다양한 형상의 반제품을 제조하는 공정이다.In general, the cast steel is produced while the molten steel contained in the mold is cooled through the cooling table. For example, the continuous casting process injects molten steel into a mold having a constant internal shape, and continuously draws the reacted slabs into the lower side of the mold to produce semi-finished products of various shapes such as slabs, blooms, billets, beam blanks, and the like. It is a process.
이러한 주조공정에서 주편은 주형 내에서 1차 냉각되고, 주형을 통과한 후 주편에 물이 분사되어 2차 냉각되는 과정을 거쳐 응고가 진행된다. 이 중 주형 내에서 일어나는 1차 냉각은 주형 내 용강의 유동과, 몰드 플럭스의 용융 거동 및 주형과 주편 사이로의 균일한 침투 능력에 의해 많은 영향을 받는다. In this casting process, the cast steel is first cooled in the mold, and after passing through the mold, solidification proceeds through a process in which water is injected into the cast steel and secondly cooled. Primary cooling occurring in the mold is greatly affected by the flow of molten steel in the mold, the melting behavior of the mold flux, and the ability to uniformly penetrate between the mold and the slab.
한편, 주조공정으로 제조된 주편에는 다양한 원인에 의해 결함이 발생하게 되는데, 이러한 결함은 주형 내에서의 용강 유동이나 주조 중 롤에 의한 하중, 인발에 의한 하중 등에 의해 발생할 수 있다. 특히, 용강 유동에 의해 발생하는 결함은 개재물과 슬래그가 혼입된 형태가 대부분이지만, 주조 중 롤에 의한 하중, 인발에 의한 하중으로 발생하는 결함은 주로 주편의 표면에 크랙으로 발생하게 되며, 주편 표면에 형성되는 크랙은 주형 내에서 용강이 1차 냉각되는 과정에서 발생할 수도 있다. On the other hand, the cast produced by the casting process is caused by a variety of causes, such defects may occur due to the flow of molten steel in the mold, the load by the roll during the casting, the load by drawing. In particular, defects caused by molten steel flow are mostly in the form of inclusions and slag, but defects caused by loads due to rolls and loads during drawing are mainly generated as cracks on the surface of the cast steel. Cracks formed in the mold may occur during the primary cooling of the molten steel in the mold.
최근 해양구조용 강은 용접성 및 저온 인성 확보를 목적으로 구리(Cu)를 첨가하고 있다. 그런데 1500℃ 정도의 고온에서 주편을 주조하는 과정에서 주편 표면부로 구리가 용출된 후 강의 결정입계로 침투하여 크랙을 유발한다. 또한, 강 중 함유되는 구리에 의해 크랙 민감도는 급격히 증가하며 그 주된 요인은 주조 중, 또는 압연을 위한 가열 중 발생하는 고온에서의 선택적인 산화에 의한 구리의 농화 때문이다. 구리는 산화 정련 시에도 산소 친화도가 매우 낮아 제거하기 어렵고, 이에 고철이 된 후에도 제품에 지속적으로 농축된다. 따라서 제선공정에서 이러한 구리가 함유되는 고철을 스크랩으로 사용하는 경우 전술한 바와 같은 현상들이 반복적으로 발생하게 된다. 이에 강에 함유된 구리의 함량에 대하여 1.5 내지 2배 가량의 니켈(Ni)을 첨가하여 주편 내 구리의 용해도를 증가시킴으로써 구리가 주편 표면으로 용출되는 현상을 억제하는 방법이 사용되고 있다.Recently, marine structural steel has been added with copper (Cu) to secure weldability and low temperature toughness. However, in the process of casting the cast at a high temperature of about 1500 ℃ copper is eluted to the surface of the cast and then penetrates into the grain boundary of the steel to cause cracks. In addition, the crack sensitivity rapidly increases due to the copper contained in the steel, mainly due to the concentration of copper by selective oxidation at high temperatures occurring during casting or during heating for rolling. Copper is difficult to remove due to its very low oxygen affinity even during oxidative refining, and it is continuously concentrated in the product even after it is scraped. Therefore, the above-described phenomenon occurs repeatedly when the scrap containing copper is used as a scrap in the steel making process. Accordingly, a method of suppressing a phenomenon in which copper is eluted to the surface of a slab by increasing the solubility of copper in the slab by adding about 1.5 to 2 times nickel (Ni) to the amount of copper contained in the steel is used.
그러나 니켈은 고가의 합금 원소로서 생산 원가를 증가시키고, 강의 응고 거동을 변동시키는 문제점이 있다. 도 1에 도시된 Fe-C 상태도를 참조하면, 강은 저탄소영역에서 1400℃ 이상의 온도에서 알파 페라이트(α(δ))로 주조되어 안정적인 응고 거동을 보인다. 그러나 도 2를 참조하면, 니켈 함량이 3중량% 미만인 경우에는 감마 오스테나이트(γ-Fe) 범위가 넓어져 액상과 델타상이 델타상과 감마상으로 변태하는 아포정 반응(다시 말해서 포정 온도 이하에서 잔류 액상 없이 고상으로 변태하는 반응)으로 변동, 즉 강의 응고 거동이 변동될 수 있다. 이러한 아포정 반응은 응고 수축이 크고 크랙에 민감하기 때문에, 이와 같은 반응으로 제조된 주편은 심각한 응고 수축에 의해 주형 내 불균일 응고가 조장되고, 이에 따라 주편 표면에 요철 구조가 형성되어 표면 크랙 등을 유발하는 문제점이 있다. However, nickel is an expensive alloying element, which increases production costs and fluctuates the solidification behavior of steel. Referring to the Fe-C state diagram shown in FIG. 1, the steel is cast as alpha ferrite (α (δ)) at a temperature of 1400 ° C. or higher in a low carbon region to exhibit stable solidification behavior. However, referring to FIG. 2, when the nickel content is less than 3% by weight, the gamma austenite (γ-Fe) range is widened so that the apolytic reaction in which the liquid phase and the delta phase are transformed into the delta phase and the gamma phase (that is, at or below the temperature of the crystallization). Fluctuations, ie the solidification behavior of the steel, can change. Since the apolytic reaction has a large coagulation shrinkage and is sensitive to cracks, the cast steel produced by such a reaction promotes uneven coagulation in the mold due to severe coagulation shrinkage, thereby forming an uneven structure on the surface of the cast steel, resulting in surface cracking and the like. There is a problem that causes.
본 발명은 주편에 형성되는 결함을 억제 혹은 방지하여 공정 효율 및 생산성을 향상시킬 수 있는 몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편을 제공한다. The present invention provides a mold flux that can suppress or prevent defects formed in the cast steel to improve process efficiency and productivity, a continuous casting method using the same, and a cast steel manufactured using the same.
본 발명은 원료의 사용량을 저감시켜 생산비용을 절감할 수 있는 몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편을 제공한다. The present invention provides a mold flux, a continuous casting method using the same and the cast produced using the same can reduce the production cost of raw materials.
본 발명의 실시 형태에 따른 몰드 플럭스는, SiO2, CaO, Na2O, Al2O3 및 CaF를 포함하는 제1몰드 플럭스; 및 알루미늄(Al) 보다 산소친화도가 낮은 금속들 중에서 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 제2몰드 플럭스;를 포함하는 것을 특징으로 한다. Mold flux according to an embodiment of the present invention, the first mold flux comprising SiO 2 , CaO, Na 2 O, Al 2 O 3 and CaF; And a second mold flux including a metal-containing material containing at least one of metals having lower oxygen affinity than aluminum (Al).
상기 제2몰드 플럭스는 니켈(Ni), 망간(Mn), 아연(Zn) 및 티타늄(Ti) 중 적어도 어느 하나의 금속 함유 물질을 포함할 수 있다. The second mold flux may include at least one metal-containing material of nickel (Ni), manganese (Mn), zinc (Zn), and titanium (Ti).
상기 제2몰드 플럭스의 용융물의 비중은 투입되는 용강의 비중보다는 낮고, 상기 제1몰드 플럭스의 용융물의 비중 보다는 높은 범위를 가질 수 있다.The specific gravity of the melt of the second mold flux may be lower than the specific gravity of the molten steel to be introduced and may have a higher range than the specific gravity of the melt of the first mold flux.
상기 제2몰드 플럭스는 금속 산화물 및 금속 분말 중 적어도 어느 하나를 포함할 수 있다.The second mold flux may include at least one of a metal oxide and a metal powder.
상기 제2몰드 플럭스의 함량은, 상기 제1 및 제2몰드 플럭스 전체 중량에 대하여 5 내지 50중량% 범위일 수 있다.The content of the second mold flux may be in a range of 5 to 50 wt% based on the total weight of the first and second mold fluxes.
본 발명의 실시 형태에 따른 연속주조방법은, 몰드에 용강을 공급하여 주편을 제조하는 연속주조방법으로서, 상기 용강 상부에 SiO2, CaO, Na2O, Al2O3 및 CaF를 포함하는 제1몰드 플럭스와, Al보다 산소친화도가 낮은 금속들 중에서 Ni, Mn, Zn 및 Ti 중 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 제2몰드 플럭스를 공급하면서 주편의 표면 적어도 일부에 상기 제2몰드 플럭스에 의한 코팅층을 형성하는 것을 특징으로 한다. The continuous casting method according to the embodiment of the present invention is a continuous casting method for manufacturing molten steel by supplying molten steel to a mold, the article comprising SiO 2 , CaO, Na 2 O, Al 2 O 3 and CaF on the molten steel The first mold flux and a second mold flux comprising a metal-containing material containing at least any one of Ni, Mn, Zn and Ti among the metals having a lower oxygen affinity than Al is supplied to at least a portion of the surface of the cast steel. It is characterized by forming a coating layer by a two-mold flux.
상기 용강은 0.1 내지 3.5중량%의 구리를 포함할 수 있다. The molten steel may include 0.1 to 3.5% by weight of copper.
상기 제1몰드 플럭스는 주조 초기에서 말기까지 연속해서 공급할 수 있다. The first mold flux may be continuously supplied from the beginning to the end of the casting.
상기 제2몰드 플럭스를 공급하는 과정은, 상기 몰드 내 용강의 탕면 변동에 따라 단속적으로 상기 제2몰드 플러그를 공급하는 과정을 포함할 수 있다.The supply of the second mold flux may include supplying the second mold plug intermittently in response to fluctuations in the surface of the molten steel in the mold.
상기 제2몰드 플럭스는 상기 몰드 내 용강의 탕면 변동 주파수가 0. 1 내지 0.25Hz일 때 공급할 수 있다.The second mold flux may be supplied when the melt surface fluctuation frequency of the molten steel in the mold is 0.01 to 0.25 Hz.
상기 제2몰드 플럭스의 함량은 상기 제1 및 제2몰드 플럭스 전체 중량에 대하여 5 내지 50중량% 범위일 수 있다.The content of the second mold flux may be in the range of 5 to 50 wt% based on the total weight of the first and second mold fluxes.
상기 제1몰드 플럭스는 상기 몰드의 중심영역에 공급하고, 상기 제2몰드 플럭스는 상기 몰드의 내벽과 인접한 영역에 공급할 수 있다.The first mold flux may be supplied to a center region of the mold, and the second mold flux may be supplied to an region adjacent to an inner wall of the mold.
상기 제2몰드 플럭스는 상기 몰드의 내벽으로부터 50㎜ 이내의 영역에 공급할 수 있다. The second mold flux may be supplied to an area within 50 mm from the inner wall of the mold.
본 발명의 실시 형태에 따른 주편은 표면의 적어도 일부에 알루미늄(Al) 보다 산소친화도가 낮은 금속들 중에서 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 코팅층이 형성되는 것을 특징으로 한다. The cast steel according to the embodiment of the present invention is characterized in that a coating layer including a metal-containing material containing at least one of metals having lower oxygen affinity than aluminum (Al) is formed on at least a part of the surface.
상기 금속 함유 물질은 Al보다 산소친화도가 낮은 금속들 중에서 Ni, Mn, Zn 및 Ti 중 적어도 어느 하나일 수 있다.The metal-containing material may be at least one of Ni, Mn, Zn, and Ti among metals having lower oxygen affinity than Al.
본 발명의 실시 형태에 따른 몰드 플럭스, 이를 이용한 연속주조방법 및 이를 이용하여 제조된 주편에 의하면, 주편 표면의 응고 거동을 제어하여 주편에 형성되는 크랙 등과 같은 결함을 억제 혹은 방지할 수 있다. 몰드 플럭스는 용강의 열에 의해 액상 슬래그가 된 후 주편과 몰드 사이로 유입된다. 주편과 몰드 사이로 유입된 몰드 플럭스는 주편을 응고시키는데 중요한 역할을 하는데, 이때 액상 슬래그 내 Al보다 산소친화도가 낮은 금속 함유 물질인 Ni, Mn, Zn, Ti, Cr이 분포하면 금속 함유 물질 입자에 의해 복사열이 산란되어 주편에 균일하고 안정되게 전달될 수 있다. 이로 인해 주편이 균일하게 응고되어 주편의 표면 품질을 향상시킬 수 있다. 또한 몰드 플럭스 내 Ni, Mn, Zn, Ti, Cr 등의 원소는 주편의 초기 응고시 표면부에 농화되어 응고 수축이 적은 과포정 반응이 일어나도록 강의 응고 거동을 제어함으로써 응고 불균일에 의한 크랙 발생을 줄일 수 있다. According to the mold flux according to the embodiment of the present invention, the continuous casting method using the same, and the cast manufactured using the same, it is possible to suppress or prevent defects such as cracks formed in the cast by controlling the solidification behavior of the surface of the cast. The mold flux becomes liquid slag by the heat of the molten steel and then flows between the slab and the mold. The mold flux introduced between the cast and the mold plays an important role in solidifying the cast. In this case, Ni, Mn, Zn, Ti, and Cr, which have a lower oxygen affinity than Al in the liquid slag, are distributed to the metal-containing material particles. By this, the radiant heat can be scattered and transmitted uniformly and stably to the cast steel. This allows the cast to solidify uniformly and to improve the surface quality of the cast. In addition, elements such as Ni, Mn, Zn, Ti, and Cr in the mold flux are concentrated on the surface during initial solidification of the cast, so that the formation of cracks due to solidification non-uniformity is controlled by controlling the solidification behavior of the steel so that superstable reactions with low solidification shrinkage occur. Can be reduced.
또한, 구리(Cu)를 함유하는 용강을 이용하여 주편을 제조하는 경우, 주편의 표면부로 액상 구리가 유출되어 농화층을 형성하는 것을 방지하여, 산소 친화도가 낮은 구리에 의한 입계 크랙이 유발되는 것을 억제 혹은 방지할 수 있다. In addition, in the case of manufacturing the cast using molten steel containing copper (Cu), liquid copper is prevented from flowing out to the surface portion of the cast to form a concentrated layer, causing grain boundary cracks due to copper having a low oxygen affinity. Can be suppressed or prevented.
또한, 주편의 표면에 산소친화도가 낮은, 예컨대 Al보다 산소친화도가 낮은 금속 함유 물질의 농화층(코팅층)을 선택적으로 형성할 수 있어 고가의 금속 함유 물질 사용에 따른 생산 비용의 증대를 억제할 수 있다. In addition, a thickening layer (coating layer) of a metal-containing material having a lower oxygen affinity, for example, a lower oxygen affinity than Al, may be selectively formed on the surface of the cast steel, thereby suppressing an increase in production cost due to the use of an expensive metal-containing material. can do.
도 1은 종래기술에 따른 연속주조방법의 문제점을 설명하기 위한 Fe-C 상태도.1 is a Fe-C state diagram for explaining the problem of the continuous casting method according to the prior art.
도 2는 용강에 Ni를 첨가한 경우 Fe-C 상태도의 변화를 보여주는 도면.2 is a view showing a change in Fe-C state diagram when Ni is added to molten steel.
도 3은 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편의 단면도 및 모식도. 3 is a cross-sectional view and a schematic view of the cast steel produced by the continuous casting method according to an embodiment of the present invention.
도 4는 본 발명의 실시 예에 따른 연속주조방법을 설명하기 위한 연속주조장치를 개략적으로 보여주는 도면.4 is a view schematically showing a continuous casting device for explaining the continuous casting method according to an embodiment of the present invention.
도 5는 본 발명의 실시 예에 따른 몰드 플럭스를 형성하는 금속 함유 물질을 설명하기 위한 산소친화도 그래프. 5 is an oxygen affinity graph for explaining a metal-containing material forming a mold flux according to an embodiment of the present invention.
도 6은 본 발명의 실시 예에 따른 몰드 플럭스의 성분 조절을 위한 실험 결과를 보여주는 도면. Figure 6 is a view showing the experimental results for the component control of the mold flux according to an embodiment of the present invention.
도 7은 본 발명의 실시 예에 따른 연속주조방법에서 금속 함유 물질을 함유하는 몰드 플럭스의 투입 시점을 설명하기 위한 도면.7 is a view for explaining the timing of the injection of the mold flux containing the metal-containing material in the continuous casting method according to an embodiment of the present invention.
도 8은 종래기술에 따른 연속주조방법과 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편을 비교한 사진 및 모식도.Figure 8 is a photograph and a schematic view comparing the cast produced in the continuous casting method according to the embodiment of the present invention and the continuous casting method according to the prior art.
도 9는 본 발명의 실시 예에 따라 제조된 주편 상태를 보여주는 모식도.9 is a schematic diagram showing a state of the cast steel produced according to an embodiment of the present invention.
이하, 본 발명의 바람직한 실시 예를 첨부도면에 의거하여 상세하게 설명한다. 그러나 본 발명은 이하에서 개시되는 실시 예에 한정되는 것이 아니라, 서로 다른 다양한 형태로 구현될 것이며, 단지 본 실시 예들은 본 발명의 개시가 완전하도록 하며, 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이다.Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and the present embodiments are only provided to make the disclosure of the present invention complete and to those skilled in the art. It is provided for complete information.
도 3은 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편의 단면도 및 모식도이고, 도 4는 본 발명의 실시 예에 따른 연속주조방법을 설명하기 위한 연속주조장치를 개략적으로 보여주는 도면이다. 3 is a cross-sectional view and a schematic view of the cast steel produced by the continuous casting method according to an embodiment of the present invention, Figure 4 is a view showing a continuous casting apparatus for explaining the continuous casting method according to an embodiment of the present invention.
도 3을 참조하면, 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편(100)은 표면에 코팅층(200)을 구비한다. 코팅층(200)은 연속주조과정에서 주편(100) 표면에 형성되며, 더 상세하게는 연속주조과정에서 몰드에 공급되는 몰드 플럭스에 의해 형성될 수 있다. 코팅층은 알루미늄(Al)보다 산소친화도가 낮은 니켈(Ni), 망간(Mn), 아연(Zn) 및 티타늄(Ti) 중 적어도 어느 하나의 금속 함유 물질을 포함하도록 형성되어, 주편 내의 구리 성분 및 용강의 응고 거동에 의해 발생하는 표면 결함을 억제할 수 있다. 즉, 코팅층에 함유된 금속 함유 물질은 주편 내 구리의 용해도를 증대시킬 수 있고, 코팅층이 형성되는 주편의 표면에서 액상 및 델타상이 감마상 및 액상으로 변태하는 과포정 반응을 일으켜 주편의 응고 수축을 저감시키고, 그에 따라 주편 표면에 크랙이 발생하는 현상을 억제할 수 있다. Referring to Figure 3, the slab 100 manufactured by the continuous casting method according to an embodiment of the present invention is provided with a coating layer 200 on the surface. The coating layer 200 may be formed on the surface of the cast steel 100 in the continuous casting process, and more specifically, may be formed by the mold flux supplied to the mold in the continuous casting process. The coating layer is formed to include a metal-containing material of at least one of nickel (Ni), manganese (Mn), zinc (Zn), and titanium (Ti), which has a lower oxygen affinity than aluminum (Al), so that the copper component and The surface defect which arises by the solidification behavior of molten steel can be suppressed. That is, the metal-containing material contained in the coating layer can increase the solubility of copper in the cast steel, and the superstable reaction in which the liquid phase and the delta phase transform into a gamma phase and a liquid phase on the surface of the cast steel on which the coating layer is formed causes a solidification shrinkage of the cast steel. It can reduce, and the phenomenon which a crack generate | occur | produces on the surface of a slab can be suppressed.
도 4에는 주편 표면에 코팅층을 형성하기 위한 연속주조장치가 도시되어 있다. 연속주조장치는 몰드(10)와, 몰드(10)에 용강(S)을 공급하는 침지노즐(20) 및 몰드(10)에 몰드 플럭스를 공급하기 위한 몰드 플럭스 공급장치(30, 32)를 포함할 수 있다. 또한, 몰드(10) 내의 용강의 탕면 변화를 측정하기 위한 센서(미도시)와, 센서에서 측정된 용강의 탕면 변화에 따라 몰드 플럭스 공급장치의 작동을 제어하는 제어기(미도시)를 포함할 수 있다. 여기에서 몰드(10)와 침지노즐(20)의 구성은 공지의 연속주조장치와 동일하므로 구체적인 설명은 생략한다. 4 shows a continuous casting apparatus for forming a coating layer on the surface of the cast steel. The continuous casting apparatus includes a mold 10, an immersion nozzle 20 for supplying molten steel S to the mold 10, and a mold flux supply device 30, 32 for supplying mold flux to the mold 10. can do. In addition, it may include a sensor (not shown) for measuring the change in the surface of the molten steel in the mold 10, and a controller (not shown) for controlling the operation of the mold flux supply apparatus according to the change in the surface of the molten steel measured by the sensor. have. Herein, the structure of the mold 10 and the immersion nozzle 20 is the same as that of a known continuous casting apparatus, and thus a detailed description thereof will be omitted.
몰드 플럭스 공급장치(30, 32)는 몰드(10) 상부에 구비되어 침지노즐(20)에 인접한 몰드(10)의 중심영역에 제1몰드 플럭스(P1)를 공급하는 제1몰드 플럭스 공급기(30)와, 몰드(10)의 벽체에 인접한 가장자리 영역에 제2몰드 플럭스(P2)를 공급하는 제2몰드 플럭스 공급기(32)를 포함할 수 있다. 이때, 제2몰드 플럭스 공급기(32)는 몰드(10)의 벽체로부터 50㎜ 이내의 영역에 제2몰드 플럭스(P2)를 공급할 수 있도록 형성될 수 있다. 이는 용강과 몰드 사이에 제2몰드 플럭스(P2)를 효율적으로 침투시키기 위한 것으로, 제2몰드 플럭스(P2)가 제시된 범위보다 넓은 영역에 걸쳐 공급되더라도 제2몰드 플럭스(P2)의 공급량과 주편 표면에 형성되는 코팅층의 두께가 비례하는 것은 아니다. 또한, 제시된 범위보다 넓은 영역에 걸쳐 제2몰드 플럭스(P2)를 공급하면, 제2몰드 플럭스(P2)의 사용량이 증가하여 제2몰드 플럭스(P2)를 형성하는 고가의 금속 함유 물질의 사용량을 절감할 수 있는 효과가 저하된다. The mold flux supply devices 30 and 32 are provided on the mold 10 to supply the first mold flux P1 to the central region of the mold 10 adjacent to the immersion nozzle 20. ) And a second mold flux feeder 32 for supplying the second mold flux P2 to the edge region adjacent to the wall of the mold 10. In this case, the second mold flux supplier 32 may be formed to supply the second mold flux P2 to a region within 50 mm from the wall of the mold 10. This is to efficiently penetrate the second mold flux P2 between the molten steel and the mold, and even if the second mold flux P2 is supplied over a wider range than the indicated range, the supply amount of the second mold flux P2 and the cast surface The thickness of the coating layer formed in the is not proportional. In addition, when the second mold flux P2 is supplied over an area wider than the suggested range, the amount of the expensive metal-containing material forming the second mold flux P2 increases by increasing the amount of the second mold flux P2. The saving effect is reduced.
제1몰드 플럭스(P1)는 SiO2, CaO, Na2O, Al2O3 및 CaF 등을 포함하고, 제2몰드 플럭스(P2)는 산소친화도가 낮은, 예컨대 알루미늄보다 산소친화도가 낮은 니켈, 망간, 아연 및 티타늄 중 적어도 어느 하나의 금속 함유 물질을 포함할 수 있다. 이때, 제2몰드 플럭스(P2)는 금속 산화물 형태로 몰드에 공급될 수도 있고, 금속 분말 형태로 몰드(10)에 공급될 수도 있다.The first mold flux P1 includes SiO 2 , CaO, Na 2 O, Al 2 O 3 , CaF, and the like, and the second mold flux P2 has a lower oxygen affinity, for example, a lower oxygen affinity than aluminum. Metal, including at least one of nickel, manganese, zinc and titanium. In this case, the second mold flux P2 may be supplied to the mold in the form of a metal oxide, or may be supplied to the mold 10 in the form of a metal powder.
센서는 몰드(10) 상부에서 몰드(10) 내 용강의 탕면 변화를 측정하고, 그 측정 결과를 제어기로 전송한다. 센서는 용강의 응고 거동에 따라 발생하는 용강의 탕면 변동 주기를 측정하며, 예컨대 자기장 변위 센서가 사용될 수 있다. 센서는 이에 한정되지 않고 다양한 종류의 센서가 사용될 수 있다. The sensor measures a change in the surface of the molten steel in the mold 10 on the mold 10, and transmits the measurement result to the controller. The sensor measures the period of fluctuation of the surface of molten steel that occurs according to the solidification behavior of the molten steel, and a magnetic field displacement sensor may be used, for example. The sensor is not limited thereto, and various types of sensors may be used.
제어기는 센서에서 측정된 결과에 따라 제1몰드 플럭스 공급기(30) 및 제2몰드 플럭스 공급기(32)의 작동을 제어하며, 제1몰드 플럭스와 제2몰드 플럭스를 몰드(10) 내에 공급한다. 또한, 용강이 구리를 함유한 경우, 제어기는 용강의 종류에 따라 제2몰드 플럭스 공급기(32)를 단속적으로 작동시켜 제2몰드 플럭스를 몰드(10)에 공급할 수 있다.The controller controls the operation of the first mold flux feeder 30 and the second mold flux feeder 32 in accordance with the results measured at the sensor, and supplies the first mold flux and the second mold flux into the mold 10. In addition, when the molten steel contains copper, the controller may intermittently operate the second mold flux feeder 32 according to the type of molten steel to supply the second mold flux to the mold 10.
이와 같은 구성을 통해 연속주조과정에서 제1몰드 플럭스(P1)와 제2몰드 플럭스(P2)를 몰드(10)에 공급함으로써 적어도 주편의 표면 일부에 코팅층을 형성할 수 있다. Through such a configuration, the coating layer may be formed on at least part of the surface of the slab by supplying the first mold flux P1 and the second mold flux P2 to the mold 10 in the continuous casting process.
도 5는 본 발명의 실시 예에 따른 몰드 플럭스를 형성하는 금속 함유 물질을 설명하기 위한 산소친화도 그래프이고, 도 6은 본 발명의 실시 예에 따른 몰드 플럭스의 성분 조절을 위한 실험 결과를 보여주는 도면이고, 도 7은 본 발명의 실시 예에 따른 연속주조방법에서 금속 함유 물질을 함유하는 몰드 플럭스의 투입 시점을 설명하기 위한 도면이다. 5 is an oxygen affinity graph for explaining a metal-containing material forming a mold flux according to an embodiment of the present invention, Figure 6 is a view showing the experimental results for the component control of the mold flux according to an embodiment of the present invention. 7 is a view for explaining the timing of the injection of the mold flux containing the metal-containing material in the continuous casting method according to an embodiment of the present invention.
본 발명에서는 적어도 주편 표면의 적어도 일부에 알루미늄(Al) 보다 산소친화도가 낮은 금속들 중에서 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 코팅층을 형성하여 주편 표면에 발생하는 크랙 등의 결함을 억제 혹은 방지할 수 있다. 이때, 금속 함유 물질은 Al보다 산소친화도가 낮은 금속들 중에서 Ni, Mn, Zn 및 Ti 중 적어도 어느 하나일 수 있다.In the present invention, at least a portion of the surface of the cast steel to form a coating layer containing a metal-containing material containing at least any one of metals having a lower oxygen affinity than aluminum (Al) to suppress defects such as cracks generated on the surface of the cast steel Or it can be prevented. In this case, the metal-containing material may be at least one of Ni, Mn, Zn, and Ti among metals having lower oxygen affinity than Al.
제2몰드 플럭스는 산소친화도가 낮은, 예컨대 알루미늄(Al)보다 산소친화도가 낮은 금속 함유 물질을 포함할 수 있다. 도 5를 참조하면, 알루미늄보다 산소친화도가 낮은 금속 함유 물질로는 티타늄, 실리콘(Si), 망간(Mn), 아연(Zn), 니켈(Ni) 등이 있으며, 여기에서 실리콘은 용접 특성을 저하시키므로 본 발명에는 적합하지 않다. 본 발명에 사용될 수 있는 금속 함유 물질 중 니켈은 주편 내 구리의 용해도를 향상시키는 효과를 구현할 수 있고, 나머지 금속 함유 물질들은 주편의 응고 거동을 제어하는 효과를 구현할 수 있다. 금속 함유 물질은 TiO2, MnO, ZnO, NiO 등과 같은 산화물 형태로 사용될 수도 있고, 금속 분말 형태로 사용될 수도 있다. 이러한 금속 함유 물질은 산소친화도가 낮기 때문에 SiO2, CaO, Na2O 등과 같이 산화물 형태로 사용되는 제1몰드 플럭스와 상호 반응이 거의 일어나지 않는다. 따라서 제1몰드 플럭스와 제2몰드 플럭스는 몰드 내로 공급된 후 용융되어 그 상태를 일정하게 유지할 수 있다. 다만, 산화물 형태의 금속 함유 물질을 사용하는 경우, 용강은 자유산소가 거의 없는 상태이기 때문에 용강 내 칼슘(Ca), 알루미늄(Al), 실리콘(Si), 철(Fe) 등과의 반응에 의해 환원되어 이온 상태로 존재하게 된다. 이때, 발생하는 반응열에 의해 탕면 보온 효과를 얻을 수 있는 이점이 있다. 그리고 금속 분말을 사용하는 경우, 반응열에 의한 탕면 보온 효과는 없지만, 주편 표면에 코팅층을 형성하는 효과는 동일하게 얻을 수 있다. The second mold flux may include a metal containing material having a lower oxygen affinity, such as a lower oxygen affinity than aluminum (Al). Referring to FIG. 5, metal-containing materials having lower oxygen affinity than aluminum include titanium, silicon (Si), manganese (Mn), zinc (Zn), nickel (Ni), and the like, wherein silicon has welding properties. Since it lowers, it is not suitable for this invention. Nickel among the metal-containing materials that can be used in the present invention can implement the effect of improving the solubility of copper in the cast steel, the remaining metal-containing materials can implement the effect of controlling the solidification behavior of the cast steel. The metal-containing material may be used in the form of an oxide such as TiO 2 , MnO, ZnO, NiO, or the like, or may be used in the form of a metal powder. Since the metal-containing material has a low oxygen affinity, the metal-containing material hardly interacts with the first mold flux used in oxide form such as SiO 2 , CaO, Na 2 O, or the like. Therefore, the first mold flux and the second mold flux may be supplied into the mold and then melted to maintain a constant state. However, in the case of using a metal-containing material in the form of oxide, since molten steel is almost free of oxygen, it is reduced by reaction with calcium (Ca), aluminum (Al), silicon (Si), iron (Fe), etc. And exist in an ionic state. At this time, there is an advantage that the warm water insulation effect can be obtained by the generated reaction heat. In the case of using a metal powder, there is no hot water insulation effect by the heat of reaction, but the effect of forming a coating layer on the surface of the cast steel can be obtained in the same manner.
한편, 제2몰드 플럭스의 용융물은 용강의 비중보다 낮고 제1몰드 플럭스의 용융물에 비해 높은 비중을 가질 수 있다. 이에 제2몰드 플럭스의 용융물은 제1몰드 플럭스의 용융물과 용강 사이에 안정적으로 위치하여 연속주조 중 몰드에 가해지는 진동에 의해 용강의 응고셀과 몰드 사이에 효율적으로 유입될 수 있다. Meanwhile, the melt of the second mold flux may have a specific gravity lower than that of the molten steel and higher than that of the melt of the first mold flux. Accordingly, the melt of the second mold flux may be stably positioned between the melt of the first mold flux and the molten steel and may be efficiently introduced between the solidification cell of the molten steel and the mold by the vibration applied to the mold during continuous casting.
전술한 바와 같이 본 발명의 실시 예에 따른 몰드 플럭스는 일반적인 연속주조공정에서 사용되는 제1몰드 플럭스와, 금속 함유 물질을 함유하는 제2몰드 플럭스를 포함한다. 제2몰드 플럭스는 제1몰드 플럭스와 제2몰드 플럭스 전체 중량에 대해서 5 내지 50중량%, 바람직하게는 10 내지 30중량%로 사용될 수 있다. 예컨대 제1몰드 플럭스는 SiO2를 13 내지 30중량%, CaO를 15 내지 40%, Al2O3, Na2O 및 CaF를 2 내지 10중량% 포함하고, 제2몰드 플럭스는 NiO를 5 내지 50중량% 포함할 수 있다. 이때, 제2몰드 플럭스의 사용량은 융제인 Na2O의 사용량에 따라 최대 50중량%까지 사용될 수 있다.As described above, the mold flux according to the embodiment of the present invention includes a first mold flux used in a general continuous casting process and a second mold flux containing a metal-containing material. The second mold flux may be used in an amount of 5 to 50% by weight, preferably 10 to 30% by weight, based on the total weight of the first mold flux and the second mold flux. For example, the first mold flux may contain 13-30 wt% SiO 2 , 15-40% CaO, 2-10 wt% Al 2 O 3 , Na 2 O and CaF, and the second mold flux may contain 5-5 NiO. It may include 50% by weight. At this time, the amount of the second mold flux may be used up to 50% by weight depending on the amount of Na 2 O flux.
도 6의 (a)는 제2몰드 플럭스 중 NiO의 함량에 따라 NiO와 용강 간의 반응 후 반응 계면에서의 Ni의 농도를 전자성분분석기(EPMA)를 통해 관찰한 주편의 사진이다. FIG. 6 (a) is a photograph of a cast steel obtained by observing the concentration of Ni at the reaction interface after the reaction between NiO and molten steel according to the content of NiO in the second mold flux through an electronic component analyzer (EPMA).
도 6의 (a)를 참조하면, NiO가 함유되는 제2몰드 플럭스를 사용하는 경우, 제2몰드 플럭스 중 NiO의 함량이 증가할수록 Ni의 침투 깊이가 깊어지는 것으로 알 수 있다. 즉, 제2몰드 플럭스 중 NiO의 함량이 5중량%일 때 주편 표면에 코팅층이 얇게 형성되는 것을 알 수 있다. 또한, 제2몰드 플럭스 중 NiO의 함량이 10중량%, 15중량% 및 20중량%로 증가할수록 Ni가 주편 표면으로부터 주편 내부로 침투하여 Ni의 농도가 높아지고 코팅층의 두께가 증가함을 알 수 있다. 이에 제2몰드 플럭스 내 NiO의 함량이 최소 5중량%인 경우 주편 표면에 코팅층의 형성이 가능함을 알 수 있고, 제2몰드 플럭스의 사용량이 증가할수록 Ni가 주편 표면으로부터 소정 깊이까지 침투하여 비교적 넓은 영역에 걸쳐 형성됨으로써 코팅층의 두께가 증가함을 알 수 있다. Referring to FIG. 6A, when the second mold flux containing NiO is used, the penetration depth of Ni becomes deeper as the content of NiO in the second mold flux increases. That is, it can be seen that when the content of NiO in the second mold flux is 5% by weight, a thin coating layer is formed on the surface of the cast steel. In addition, as the content of NiO in the second mold flux increased to 10% by weight, 15% by weight and 20% by weight, it was found that Ni penetrated into the slab from the surface of the slab to increase the concentration of Ni and the thickness of the coating layer. . Therefore, when the content of NiO in the second mold flux is at least 5% by weight, it can be seen that a coating layer can be formed on the surface of the cast steel. As the amount of the second mold flux is increased, Ni penetrates to the predetermined depth from the surface of the cast steel so that it is relatively wide. It can be seen that the thickness of the coating layer increases by being formed over the area.
도 6의 (b)는 주조 중 제2몰드 플럭스의 용융 특성을 모사한 사진이다. 왼쪽의 사진은 제2몰드 플럭스의 기본 물성을 측정하기 위한 것으로, 초기에는 사각형 형태로 만들어 두지만 가열하면서 시간이 경과할수록 그 형태가 Sintering-Softening-Sphere-1/2 sphere-Fusion 형태로 변형된다. 이를 기준으로 NiO를 포함하는 제2몰드 플럭스를 이용하여 초기 형태로 나타나는 시편을 제조하고 이를 1300℃ 정도로 가열하여 용융 상태를 측정한 것이다. 도 6의 (b)에서 오른쪽에 도시된 사진은 NiO의 함량에 따른 시편의 용융 상태를 나타내는 것이다. 이를 살펴보면 NiO의 함량을 30중량% 내지 80중량%의 범위에서 10중량%씩 증가시킨 경우, 50중량%까지는 시편이 어느 정도 용융된 것을 알 수 있으나, 60중량% 내지 80중량%의 범위에서는 제2몰드 플럭스의 용융이 거의 일어나지 않음을 알 수 있다. 이에 제2몰드 플럭스는 5중량% 내지 50중량% 범위에서 적절하게 사용하면 몰드 내에서 용융되어 액상 슬래그 형태로 변경된 후 몰드와 주편 사이로 유입되어 주편의 표면에 코팅층을 형성할 수 있음을 알 수 있다. 6B is a photograph that simulates the melting characteristics of the second mold flux during casting. The picture on the left is for measuring the basic properties of the second mold flux, which is initially made into a rectangular shape, but the shape is deformed into Sintering-Softening-Sphere-1 / 2 sphere-Fusion form as time passes. . Based on this, a specimen that appears in its initial form using a second mold flux containing NiO was prepared, and then heated to about 1300 ° C. to measure a molten state. The photo shown on the right in Figure 6 (b) shows the melt state of the specimen according to the content of NiO. Looking at this, when the content of NiO is increased by 10% by weight in the range of 30% by weight to 80% by weight, it can be seen that the specimen is melted to some extent up to 50% by weight, but in the range of 60% by weight to 80% by weight It can be seen that melting of the two mold flux hardly occurs. Thus, when the second mold flux is suitably used in the range of 5% by weight to 50% by weight, the second molten flux may be melted in the mold, changed into a liquid slag form, and then flows between the mold and the slab to form a coating layer on the surface of the slab. .
또한, 제2몰드 플럭스는 주편을 주조하는데 사용되는 용강의 종류, 예컨대 구리의 함유량에 따라 선택적으로 공급될 수 있다. 예컨대 일반 강을 이용하여 주편을 주조하는 경우, 제1몰드 플럭스는 주조 초기부터 지속적으로 공급될 수 있고, 제2몰드 플럭스는 주편의 응고 거동에 따라 탕면 변동이 있는 경우 선택적으로 공급될 수 있다. In addition, the second mold flux may be selectively supplied according to the type of molten steel used for casting the cast steel, for example, the content of copper. For example, when casting a cast using a common steel, the first mold flux may be continuously supplied from the beginning of the casting, the second mold flux may be selectively supplied when there is a fluctuation in the surface according to the solidification behavior of the cast.
도 7은 주편을 주조하는 과정에서 센서를 이용하여 용강의 탕면 변동을 측정한 결과를 보여준다. 여기에서 주조 중 용강의 탕면이 일정한 주파수 크기를 유지하다가 특정 영역에서 주파수 크기가 급격하게 증가하고 있다. 이때, 탕면 변동 주기를 FFT(fast fourier transform)분석을 통해 주된 변동 주파수를 측정하면 약 0.1 내지 0.25Hz로 나타나는데, 이는 정상 연속주조 상태에서 불균일 응고가 발생하는 주기가 탕면 변동의 주기에 영향을 주어 나타나게 된다. 이에 몰드 내에 제2몰드 플럭스를 공급하면 용강의 탕면 변동이 감소하게 되는데, 제2몰드 플럭스의 공급으로 주편 표면에 코팅층이 형성되면서 응고 거동이 안정화되었기 때문이다. Figure 7 shows the result of measuring the fluctuation of the molten steel of the molten steel using a sensor in the process of casting the cast. Here, while the hot water surface of molten steel maintains a constant frequency magnitude during casting, the frequency magnitude increases rapidly in a specific region. In this case, when the main fluctuation frequency is measured by FFT (fast fourier transform) analysis, the frequency of fluctuation appears as about 0.1 to 0.25 Hz, which is caused by non-uniform coagulation in the continuous continuous casting state. Will appear. The supply of the second mold flux into the mold reduces the fluctuation of the molten steel surface because the solidification behavior is stabilized as the coating layer is formed on the surface of the cast steel by the supply of the second mold flux.
한편, 구리를 함유하는 강, 예컨대 1 내지 3.5중량% 이상의 구리를 함유하는 강을 이용하여 주편을 주조하는 경우, 제1몰드 플럭스와 제2몰드 플럭스는 주조 초기에서 말기까지 지속적으로 공급할 수 있다. 이는 구리를 함유하는 강은 용강 중 구리 성분이 주편 표면으로 농화되어 주편 제조 후 주편 표면에 크랙을 발생시킬 수 있으므로 제2몰드 플럭스를 주조 과정에서 지속적으로 공급함으로써 주편 표면 전체에 걸쳐 코팅층을 형성할 수 있다. 이에 주편 표면에 제2몰드 플럭스에 의한 코팅층이 형성되어 구리의 입계 침투에 의한 주편의 표면 결함을 억제할 수 있다. On the other hand, when casting a cast using a steel containing copper, such as steel containing 1 to 3.5% by weight or more of copper, the first mold flux and the second mold flux can be continuously supplied from the beginning to the end of the casting. This is because the steel containing copper may concentrate on the surface of the cast steel in the molten steel, which may cause cracks on the surface of the cast steel, thereby continuously supplying the second mold flux during the casting process, thereby forming a coating layer over the surface of the cast steel. Can be. As a result, a coating layer is formed on the surface of the cast steel by the second mold flux, thereby suppressing surface defects of the cast steel due to the grain boundary penetration of copper.
이와 같이 주편 표면에 제2몰드 플럭스에 의한 금속 함유 물질을 이용하여 코팅층을 형성하면, 종래에 용강 중에 금속 함유 물질, 예컨대 니켈(Ni)을 투입할 때보다 적은 양으로도 주편의 응고 거동을 안정화시키고, 구리의 입계 침투를 억제할 수 있다. 또한, 별도의 추가 공정 없이 연속주조과정에서 주편 표면에 코팅층을 용이하게 형성할 수 있어, 설비 증대에 따른 비용 증가나 생산 시간 증가에 따른 생산량 감소 등의 문제가 없다. As such, when the coating layer is formed on the surface of the slab using a metal-containing material by the second mold flux, the solidification behavior of the slab is stabilized even with a smaller amount than when a metal-containing material such as nickel (Ni) is added to molten steel. The grain boundary penetration of copper can be suppressed. In addition, it is possible to easily form a coating layer on the surface of the cast during the continuous casting process without a separate additional process, there is no problem such as cost increase due to the increase in equipment or decrease in production amount due to the increase in production time.
이하에서는 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편의 성능을 평가하기 위한 실험 예에 대해서 설명한다. Hereinafter, an experimental example for evaluating the performance of the cast steel produced by the continuous casting method according to an embodiment of the present invention.
도 8은 종래기술에 따른 연속주조방법과 본 발명의 실시 예에 따른 연속주조방법으로 제조된 주편을 비교한 사진 및 모식도이고, 도 9는 본 발명의 실시 예에 따라 제조된 주편 상태를 보여주는 모식도이다. 8 is a photograph and a schematic view comparing the cast steel produced by the continuous casting method according to the embodiment of the present invention and the continuous casting method according to the prior art, Figure 9 is a schematic diagram showing the state of the cast steel produced according to an embodiment of the present invention. to be.
본 실험 예에서는 NiO 20중량%를 첨가한 몰드 플럭스(제2몰드 플럭스)를 이용하여 주편을 제조하였고, 이때 강종은 구리를 0.35중량% 함유한 강종이며 대표 성분은 탄소 0.1중량%, Si 0.3중량%, Mn 1.5중량%, Ni 0.02중량%, Ti 0.03중량%이다. 이때, 강 중에 함유된 니켈(Ni)은 합금 철에 의한 오염으로 함유된 것으로, 다른 합금철에 의해 매우 낮은 함량이 들어있지만 Ni이 효과를 발휘하기 위해서는 구리 대비 1.5 ~ 2배 이상 들어가야 하므로 Ni의 효과는 무시할 수 있다. In the present experimental example, the cast steel was manufactured using a mold flux (second mold flux) to which 20 wt% NiO was added. In this case, the steel grade was 0.35 wt% copper, and the representative components were 0.1 wt% carbon and 0.3 wt% Si. %, Mn 1.5 weight%, Ni 0.02 weight%, Ti 0.03 weight%. At this time, nickel (Ni) contained in the steel is contained due to contamination by alloy iron, but very low content by other ferroalloy, but Ni must be 1.5 ~ 2 times or more compared to copper in order to achieve the effect of Ni The effect can be ignored.
실험 예에서는 주조 초기 일반 몰드 플럭스, 예컨대 제1몰드 플럭스만 공급하면서 주편을 주조하였다. 이후 불균일 응고로 인해 도 7에서와 같이 초기에 탕면 변동이 발생한 시점에서 제1몰드 플럭스와 함께 NiO가 20중량% 포함된 제2몰드 플럭스를 투입하면서 주편을 주조하였다. In the experimental example, the cast was cast while supplying only the initial mold mold flux, for example, the first mold flux. Thereafter, as shown in FIG. 7, the cast was cast while the second mold flux containing 20% by weight of NiO was added together with the first mold flux at the time when the fluctuation of the water surface occurred as shown in FIG. 7.
주조된 주편의 상태를 살펴보면, 주조 초기 제1몰드 플럭스를 이용하여 주조된 주편에서는 표면에 면세로 크랙과 면가로 크랙이 주편 전반에 걸쳐 발생하였고, 가로방향의 오실레이션 마크가 깊게 형성된 것을 알 수 있다(도 8의 (a) 참조). 하지만 NiO를 20중량% 첨가한 제2몰드 플럭스를 이용하여 주조된 주편의 경우 주편 전반에 걸쳐 크랙이 전혀 발생하지 않았으며, 오실레이션 마크의 깊이도 현저하게 감소한 것을 확인할 수 있다(도 8의 (b) 참조). Looking at the state of the cast cast, it can be seen that in the cast cast using the first mold flux of the initial casting, cracks were formed in the surface of the cast along the surface and cracks along the surface side, and the oscillation mark in the horizontal direction was deeply formed. (See FIG. 8A). However, in the case of castings cast using the second mold flux containing 20% by weight of NiO, cracks did not occur at all throughout the cast steel, and the depth of the oscillation mark was also markedly reduced. b)).
또한, 주편 표층에 Ni에 의한 농화층이 형성되었는지 확인하기 위해서 전자성분분석 방법인 EPMA(Electron Probe Micro-Analysis)를 통해 주편 내 성분을 측정하였다. 도 9는 EPMA 결과로서, 왼쪽 상단(CP)은 주편의 초기형상, 오른쪽 상단(Cu)은 주편 내 구리(Cu) 성분의 위치, 왼쪽 하단(Ni)은 주편 내 니켈(Ni)의 위치, 오른쪽 하단(Fe)은 철(Fe) 성분의 위치를 나타낸다. 이를 살펴보면, NiO를 포함하는 몰드 플럭스(제2몰드 플럭스)를 이용하여 주조된 주편의 표면에는 고농도의 Ni층(코팅층)이 형성된 것을 알 수 있다. 이렇게 주편의 표면에 고농도의 Ni층이 형성됨으로써 용강 중에 존재하던 Cu는 선택적 산화(Fe가 외부의 산소와 접촉하는 경우 Cu를 제외하고 산화되어 Cu가 주편 표면에 남아 있는 현상)가 일어나더라도 주편 내부까지 침투하지 못하므로 주편 표면에 크랙이 발생하는 것을 억제할 수 있다.In addition, in order to determine whether a concentrated layer formed by Ni was formed on the surface of the slab, the components in the slab were measured through an electronic component analysis method EPMA (Electron Probe Micro-Analysis). 9 is an EPMA result, the upper left (CP) is the initial shape of the cast, the upper right (Cu) is the position of the copper (Cu) component in the slab, the lower left (Ni) is the position of nickel (Ni) in the cast, right The lower end Fe represents the position of the iron component. Looking at this, it can be seen that a high concentration of Ni layer (coating layer) is formed on the surface of the cast steel cast using the mold flux (Ni 2nd flux) containing NiO. As a high concentration of Ni layer is formed on the surface of the cast steel, Cu existing in molten steel may be selectively oxidized (a phenomenon in which Cu remains on the surface of the cast steel when the Fe contacts with external oxygen). Since it does not penetrate to, it is possible to suppress the occurrence of cracks on the surface of the cast steel.
이와 같이, 본 발명의 상세한 설명에서는 구체적인 실시 예에 관해 설명하였으나, 본 발명의 범주에서 벗어나지 않는 한도 내에서 여러 가지 변형이 가능함은 물론이다. 그러므로, 본 발명의 범위는 설명된 실시 예에 국한되어 정해져서는 안되며, 후술하는 특허청구범위뿐만 아니라 이 청구범위와 균등한 것들에 의해 정해져야 한다.As described above, in the detailed description of the present invention, specific embodiments have been described. However, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.
본 발명에 따른 몰드 플럭스 및 이를 이용한 연속주조방법은 주편 표면의 응고 거동을 제어하여 주편에 형성되는 크랙 등과 같은 결함을 억제 혹은 방지함으로써 해양구조용 강의 용접성 및 저온 인성 확보를 용이하게 할 수 있다. The mold flux according to the present invention and the continuous casting method using the same can facilitate securing the weldability and low temperature toughness of marine structural steel by controlling the solidification behavior of the surface of the cast steel to suppress or prevent defects such as cracks formed in the cast steel.

Claims (15)

  1. SiO2, CaO, Na2O, Al2O3 및 CaF를 포함하는 제1몰드 플럭스;및A first mold flux comprising SiO 2 , CaO, Na 2 O, Al 2 O 3 and CaF; and
    알루미늄(Al) 보다 산소친화도가 낮은 금속들 중에서 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 제2몰드 플럭스;를 포함하는 몰드 플럭스. And a second mold flux comprising a metal containing material containing at least one of metals having lower oxygen affinity than aluminum (Al).
  2. 청구항 1에 있어서, The method according to claim 1,
    상기 제2몰드 플럭스는 니켈(Ni), 망간(Mn), 아연(Zn) 및 티타늄(Ti) 중 적어도 어느 하나의 금속 함유 물질을 포함하는 몰드 플럭스. And the second mold flux comprises at least one metal containing material of nickel (Ni), manganese (Mn), zinc (Zn) and titanium (Ti).
  3. 청구항 1 또는 청구항 2에 있어서,The method according to claim 1 or 2,
    상기 제2몰드 플럭스의 용융물의 비중은 투입되는 용강의 비중보다는 낮고, 상기 제1몰드 플럭스의 용융물의 비중 보다는 높은 범위를 가지는 몰드 플럭스.The specific flux of the melt of the second mold flux is lower than the specific gravity of the molten steel is injected, the mold flux having a range higher than the specific gravity of the melt of the first mold flux.
  4. 청구항 1 또는 청구항 2에 있어서, The method according to claim 1 or 2,
    상기 제2몰드 플럭스는 금속 산화물 및 금속 분말 중 적어도 어느 하나를 포함하는 몰드 플럭스.And the second mold flux comprises at least one of metal oxide and metal powder.
  5. 청구항 1 또는 청구항 2에 있어서, The method according to claim 1 or 2,
    상기 제2몰드 플럭스의 함량은, 상기 제1 및 제2몰드 플럭스 전체 중량에 대하여 5 내지 50중량% 범위인 몰드 플럭스.The content of the second mold flux is in the range of 5 to 50% by weight relative to the total weight of the first and second mold flux.
  6. 몰드에 용강을 공급하여 주편을 제조하는 연속주조방법으로서, As a continuous casting method for manufacturing molten steel by supplying molten steel to the mold,
    상기 용강 상부에 SiO2, CaO, Na2O, Al2O3 및 CaF를 포함하는 제1몰드 플럭스와, Al보다 산소친화도가 낮은 금속들 중에서 Ni, Mn, Zn 및 Ti 중 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 제2몰드 플럭스를 공급하면서 주편의 표면 적어도 일부에 상기 제2몰드 플럭스에 의한 코팅층을 형성하는 연속주조방법. At least one of Ni, Mn, Zn, and Ti among the first mold flux including SiO 2 , CaO, Na 2 O, Al 2 O 3, and CaF on the molten steel, and metals having lower oxygen affinity than Al A continuous casting method for forming a coating layer by the second mold flux on at least a portion of the surface of the cast while supplying a second mold flux containing a metal-containing material.
  7. 청구항 6에 있어서, The method according to claim 6,
    상기 용강은 0.1 내지 3.5중량%의 구리를 포함하는 연속주조방법. The molten steel is a continuous casting method containing 0.1 to 3.5% by weight of copper.
  8. 청구항 7에 있어서, The method according to claim 7,
    상기 제1몰드 플럭스는 주조 초기에서 말기까지 연속해서 공급하는 연속주조방법. Continuous casting method of supplying the first mold flux continuously from the beginning to the end of the casting.
  9. 청구항 6에 있어서, The method according to claim 6,
    상기 제2몰드 플럭스를 공급하는 과정은, 상기 몰드 내 용강의 탕면 변동에 따라 단속적으로 상기 제2몰드 플러그를 공급하는 과정을 포함하는 연속주조방법.The supplying of the second mold flux may include supplying the second mold plug intermittently in response to fluctuations in the surface of the molten steel in the mold.
  10. 청구항 9에 있어서, The method according to claim 9,
    상기 제2몰드 플럭스는 상기 몰드 내 용강의 탕면 변동 주파수가 0. 1 내지 0.25Hz일 때 공급하는 연속주조방법. And the second mold flux is supplied when the frequency of fluctuation of the molten steel in the mold is 0.01 to 0.25 Hz.
  11. 청구항 6 내지 청구항 10 중 어느 한 항에 있어서, The method according to any one of claims 6 to 10,
    상기 제2몰드 플럭스의 함량은 상기 제1 및 제2몰드 플럭스 전체 중량에 대하여 5 내지 50중량% 범위인 연속주조방법.The content of the second mold flux is a continuous casting method in the range of 5 to 50% by weight relative to the total weight of the first and second mold flux.
  12. 청구항 11에 있어서, The method according to claim 11,
    상기 제1몰드 플럭스는 상기 몰드의 중심영역에 공급하고, The first mold flux is supplied to the center region of the mold,
    상기 제2몰드 플럭스는 상기 몰드의 내벽과 인접한 영역에 공급하는 연속주조방법. And the second mold flux is supplied to an area adjacent to an inner wall of the mold.
  13. 청구항 12에 있어서, The method according to claim 12,
    상기 제2몰드 플럭스는 상기 몰드의 내벽으로부터 50㎜ 이내의 영역에 공급하는 연속주조방법. And the second mold flux is supplied to an area within 50 mm from the inner wall of the mold.
  14. 표면에 알루미늄(Al) 보다 산소친화도가 낮은 금속들 중에서 적어도 어느 하나를 함유하는 금속 함유 물질을 포함하는 코팅층이 형성된 주편.Cast steel formed with a coating layer comprising a metal-containing material containing at least one of the metals having a lower oxygen affinity than aluminum (Al) on the surface.
  15. 청구항 14에 있어서, The method according to claim 14,
    상기 금속 함유 물질은 Al보다 산소친화도가 낮은 금속들 중에서 Ni, Mn, Zn 및 Ti 중 적어도 어느 하나인 주편.Wherein the metal-containing material is at least one of Ni, Mn, Zn, and Ti among metals having lower oxygen affinity than Al.
PCT/KR2014/011349 2014-02-13 2014-11-25 Mold flux, continuous casting method using same, and slab manufactured using same WO2015122602A1 (en)

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CN110695330A (en) * 2019-10-18 2020-01-17 山东钢铁股份有限公司 Stable casting method for sizing nozzle of special-shaped blank tundish
EP3533534A4 (en) * 2016-10-27 2020-03-18 Posco Structure for casting, and casting method using same
CN113857448A (en) * 2021-11-29 2021-12-31 东北大学 Low-alkalinity coating-free protective slag for continuous casting of hot forming steel
CN114918386A (en) * 2022-05-27 2022-08-19 鞍钢股份有限公司 Slag consumption measuring and alarming method and system based on slag adding machine

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EP3533534A4 (en) * 2016-10-27 2020-03-18 Posco Structure for casting, and casting method using same
CN110695330A (en) * 2019-10-18 2020-01-17 山东钢铁股份有限公司 Stable casting method for sizing nozzle of special-shaped blank tundish
CN113857448A (en) * 2021-11-29 2021-12-31 东北大学 Low-alkalinity coating-free protective slag for continuous casting of hot forming steel
CN114918386A (en) * 2022-05-27 2022-08-19 鞍钢股份有限公司 Slag consumption measuring and alarming method and system based on slag adding machine
CN114918386B (en) * 2022-05-27 2023-06-20 鞍钢股份有限公司 Slag consumption measuring and alarming method and system based on slag adding machine

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