• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    PURPOSE: A method of refining a molten metal for an electrical sheet is provided to obtain high quality of molten metal refining for manufacturing target steel and to continuously cast steel sheets without problems such as clogging of nozzles owing to temperature fall of molten metal. CONSTITUTION: A temperature and an oxygen density of a molten metal are measured in a ladle(5). That is, A vapor pressure of a vacuum bath(1) is about 7.0kg/cm¬2 to secure initial vacuum if the molten metal has the oxygen density of 200-250PPM and low temperature of 1590°C owing to temperature fall of molten metal in flowing into the ladle. At the same time, Ar gas of 200Nm3 per hour is supplied to a rising pipe(3) deposited into the ladle to return the molten metal, and the elements of molten metal is adjusted by injecting Fe-P alloy iron through an inlet(8). After about 3min, oxygen is sprayed at a high speed through a nozzle(7) and about 1-3kg of Al per ton of molten metal is injected through the inlet to raise the temperature of molten metal if the oxygen in molten metal is secured not less than 400ppm.
    公开号:KR20000042707A
    申请号:KR1019980058973
    申请日:1998-12-26
    公开日:2000-07-15
    发明作者:안승관
    申请人:이구택；포항종합제철 주식회사；
    IPC主号:
    专利说明:

    Molten steel refining method for electric steel sheet manufacturing
    The present invention relates to a molten steel refining method for the production of non-oriented electrical steel sheet, in particular, to ensure the smooth separation of the inclusion and control the components while maintaining the temperature of the molten steel to a temperature sufficient to ensure the continuous casting of the steel sheet smoothly The present invention relates to a molten steel refining method for manufacturing an electrical steel sheet which can improve the quality and continuous castability of a steel sheet.
    Non-oriented electrical steel sheet, which is the object of manufacture of the present invention, is a steel plate mainly used for small motor iron core materials and is used as 0.05 to 0.005% of C, 0.35 to 0.45% of Si, 0.20 to 0.30% of Mn, and 0.05 to 0.07% of It is steel grade which contains P, and it is required to contain components, such as S, Al, Ni, etc. as minimum as possible.
    In general, the manufacture of electrical steel sheet is to pretreat the molten iron from the blast furnace to minimize the S component in the steel, and through the converter blasting process, the molten steel in the non-deoxidation state with high oxygen concentration in the steel is subjected to vacuum degassing (RH) process. Blows and decarburizes, adds ferrous alloys containing P and Mn, adjusts the components, adds Fe-Si and Al, and deoxidizes them to make molten steel in the desired state, and then puts them into a continuous casting mold. It is made by continuous casting with a steel sheet of thickness.
    The present invention relates to the refining process of molten steel using the vacuum degassing (RH) refining equipment, in particular during the electrical steel sheet manufacturing process.
    1 is a schematic diagram illustrating the construction and refining principle of a general vacuum degassing refining equipment. The vacuum chamber 1 is installed on the ladle 5 in which the molten steel 6 to be treated is accommodated. In the lower part of the tank 1, the molten steel rising pipe 3 and the downfalling pipe 2 which are deposited in the molten steel 6 inside the ladle 5 are installed in the illustrated mode.
    In the refining process of molten steel through the vacuum degassing refining facility, the pressure of the vacuum is 6.0 kg / cm 2, and the pressure of the vacuum chamber 1 is reduced to an appropriate vacuum level, and reflux gas is applied to the ladle 5 as shown in FIG. 1. When reflux gas such as Ar is supplied to the ascending pipe 3 through the reflux gas supply pipe 4 to supply 80 to 100 Nm 3 per hour to reflux the molten steel, the molten steel 6 in the ladle 5 is vacuumed. The suction of the tank 1 flows into the vacuum chamber 1 via the riser tube 3 and then flows back into the ladle 5 through the downcomer 2 to form a reflux of the molten steel in the vacuum chamber. Degassing of molten steel, separation of inclusions is made, and refining of molten steel is performed.
    At this time, when the reflux gas is blown into the rising pipe 3 at a flow rate of about 100 Nm 3 / Hr, the molten steel is raised to a height of about 1500 mm in the inside of the vacuum chamber 1, although there is a difference depending on conditions such as vacuum degree. As the molten steel in the vacuum chamber 1 is lowered into the ladle 5 through the downcoming pipe 2, the C in the molten steel reacts with the oxygen blown through the oxygen blowing tube installed in the vacuum chamber 1. Decarburization takes place.
    At the same time as the decarburization through this process, a splash of molten steel occurs and the temperature of the molten steel drops rapidly due to the temperature difference between the inner wall of the vacuum chamber 1 and the molten steel.
    In this process, if the temperature of the molten steel falls below the level before tapping into the continuous casting mold, the fluidity of the molten steel becomes poor and the nozzle of the tundish becomes clogged, resulting in a problem that the cast iron becomes impossible or the continuous casting is impossible. It was.
    Conventionally, in order to solve the problem of the temperature drop of molten steel in the vacuum degassing refining process as described above, Al was added to molten steel after deoxidation, but the temperature of molten steel was increased, but the characteristics of the non-oriented electrical steel sheet, which is the object of the present invention, are low. In achieving the Al content and the high Si content, the elevated temperature due to such Al addition is undesirable.
    In addition, induction of exothermic reaction by injecting oxygen after deoxidation, as shown in the following reaction formula, some Al reacts with oxygen first, but after Al also reacts with Si having good affinity with oxygen, the Si component ratio is unstable in the target steel grade. In addition, there is a problem that nozzle clogging caused by inclusions is remarkably caused in a later process.
    2Al + 3/2 O 2 → Al 2 O 3
    Si + O 2 → SiO 2
    In addition, in a conventional method, in the vacuum degassing refining process, when the arrival temperature of the molten steel is low, oxygen is blown in, and when the decarburization is completed, a large amount of Al is added at the deoxidation time point to bring about a rise in the temperature of the molten steel. In the production of the target steel grade, the above method cannot be used because Si, not Al, should be used as the deoxidizer.
    The present invention can effectively solve the above-mentioned conventional problems to achieve a high-quality refinement of molten steel for the production of the target steel grade while smoothly continuous steel sheet without problems such as nozzle clogging in the post-process due to the temperature drop of molten steel The purpose is to provide a molten steel refining method that can be cast.
    1 is a configuration diagram of a general vacuum degassing refining equipment,
    2 is a configuration diagram of a refining plant for carrying out the method of the present invention.
    <Explanation of symbols for main parts of drawing>
    1: vacuum chamber 2: downcomer
    3: rising pipe 4: reflux gas supply pipe
    5: ladle 6: molten steel
    7: Oxygen injection nozzle 8: Alloy iron inlet
    9: vent
    The present invention for achieving the above object is provided with a ladle (5) in which the molten steel to be treated and the vacuum chamber (1) disposed on the ladle and the molten steel riser (3) deposited on the ladle (5) In the molten steel refining which performs degassing, inclusion separation, and component control of molten steel under vacuum depressurization and reflux gas supply in a vacuum degassing apparatus having a vacuum pipe and a down pipe (2) After supplying the molten steel in the ladle to reflux, and then blow oxygen to secure the temperature of the molten steel to secure a sufficient amount of oxygen, the molten steel refining method for producing electrical steel sheet, characterized in that divided into 1 to 3kg per ton of molten steel. .
    In the present invention, it is also supplied with a reflux gas at the same time as the vacuum decompression before oxygen injection, and the Fe-P alloy iron is added to adjust the components at the time of refluxing molten steel, and the Fe-Si is added after the decarburization is completed by raising the molten steel temperature To deoxidize.
    Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
    Figure 2 shows the schematic structure and refining principle of the refining equipment for performing the molten steel refining method of the present invention described above.
    The equipment for carrying out the present invention is provided with a container-shaped ladle 5 with an open upper side capable of accommodating molten steel 6 to be treated, and a vacuum having an exhaust gas exhaust port 9. A tank (1) is installed on the upper part thereof, and a molten steel rising pipe (3) and a down pipe (2), which are deposited in the molten steel (6) in the ladle (5), are installed under the vacuum chamber (1). It is the structure which provided the reflux gas supply pipe 4 to (5).
    In addition, an oxygen injection nozzle 7 is provided on one side of the vacuum chamber 1 so as to blow high pressure oxygen into the vacuum chamber 1 from a position higher than the molten steel rising surface inside the vacuum chamber 1, The upper portion of the alloy iron inlet (8) is provided.
    Referring to the molten steel refining process of the present invention carried out through the vacuum degassing refinery of such a configuration as follows.
    When the molten steel to be treated arrives at the ladle 5, the temperature and oxygen concentration of the molten steel are measured. If the molten steel is in the non-deoxidation state having oxygen in the concentration of 200 to 250 PPM, and the molten steel temperature drops during the transfer to the ladle and has a low temperature of about 1590 ° C, the vapor pressure of the vacuum chamber 1 is 7.0 kg. / ㎠ to ensure the initial vacuum therein and at the same time through the reflux gas supply pipe 4 to supply 200Nm 3 of Ar gas per hour to the rising pipe (3) deposited on the ladle (5) to reflux the molten steel, and At the same time, Fe-P alloy iron is introduced through the ferroalloy 8 to adjust the composition of molten steel.
    The initial introduction of Fe-P alloy iron is to prevent the fall of molten steel temperature after deoxidation and insufficient reflux time, which is disadvantageous for continuous casting. That is, in the conventional case, after the deoxidation, the alloy fine iron containing P, Mn, etc. was added to finely adjust the components. It is to prevent this because it is difficult to achieve the target composition because it is not made and can cause a temperature drop and nozzle clogging.
    In addition, the supply of reflux gas to 200 Nm 3 or more and the vapor pressure of the vacuum tank to 7.0 kg / cm 2 is to ensure sufficient reflux time of molten steel and effectively decarburize.
    Subsequently, after a predetermined time (about 3 minutes) after the addition of ferroalloy for component adjustment, oxygen is blown at a high speed through the oxygen injection nozzle (7), and the oxygen concentration in the molten steel is measured to obtain a temperature of 400 ppm or more. In order to make 1 to 3 kg of Al per ton of molten steel through the ferroalloy inlet (8).
    Dividing Al into 1 to 3 kg per ton of molten steel reacts with blown oxygen to form aluminum oxide to generate heat to raise the temperature of molten steel without affecting the side and decarburization reaction. Considering the fact that Al content should be minimized in composition.
    If a large amount of Al is added at a time, a higher temperature can be expected, but since a decarburization reaction may not be performed, a small amount must be separately added.
    When the oxygen concentration is about 400 ppm, it does not interfere with decarburization while reacting with 1-3 kg of Al.
    The reaction between Al and O 2 is an exothermic reaction, and 10 to 20 kg of Al is sufficient to raise the molten steel temperature by 10 ° C.
    As described above, Al is added while securing sufficient oxygen by oxygen injection to raise the temperature of the molten steel, and oxygen injection is completed to secure decarburization time.
    When it is determined that decarburization is completed, Fe-Si is introduced into the molten steel through the ferrous alloy inlet 8 for deoxidation, and the molten steel is fully refluxed by reflux gas to separate completely and incite the inclusions.
    At this time, the amount of Fe-Si added for deoxidation is added in an amount of about 6.7 kg per ton of molten steel (2 tons of Fe-Si for 300 tons of molten steel) to achieve a target component of the electrical steel sheet.
    The exhaust gas generated inside the vacuum chamber 1 in the refining process is discharged through the exhaust port 9.
    Therefore, the present invention can refine the molten steel of the target component to a high quality by performing decarburization and completely deoxidation in the state of efficiently raising the temperature of the molten steel arriving at the ladle as described above, and raising the temperature higher than the reference temperature. As the molten steel can be supplied to the casting mold in a state, the casting productivity can be improved, and the non-oriented electrical steel sheet, which is a material for the small motor core, can be produced with higher quality.
    权利要求:
    Claims (3)
    [1" claim-type="Currently amended] And a ladle (5) in which the molten steel to be treated is received, and a vacuum chamber (1) disposed above the ladle, and having a molten steel riser (3) and a downcomer (2) deposited on the ladle (5). In the molten steel refining which performs degassing, inclusion separation, and component control of molten steel under vacuum depressurization and reflux gas supply in a vacuum degassing apparatus, the molten steel in the ladle is refluxed by supplying reflux gas at the same time as reducing the vacuum tank. The molten steel refining method for manufacturing an electrical steel sheet, characterized in that the injection of oxygen to increase the molten steel temperature to secure a sufficient amount of oxygen, and split Al into 1 to 3 kg per ton of molten steel.
    [2" claim-type="Currently amended] The molten steel refining method for manufacturing steel sheet according to claim 1, wherein a reflux gas is supplied simultaneously with the vacuum depressurization prior to oxygen injection to inject Fe-P alloy iron for adjusting components at the time of refluxing molten steel.
    [3" claim-type="Currently amended] The molten steel refining method for manufacturing an electric steel sheet according to claim 1, wherein the molten steel temperature is raised to deoxidize by adding Fe-Si after the decarburization is completed.
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    同族专利:
    公开号 | 公开日
    KR100399220B1|2004-02-11|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-12-26|Application filed by 이구택, 포항종합제철 주식회사
    1998-12-26|Priority to KR19980058973A
    2000-07-15|Publication of KR20000042707A
    2004-02-11|Application granted
    2004-02-11|Publication of KR100399220B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR19980058973A|KR100399220B1|1998-12-26|1998-12-26|Refining method for steel sheet manufacturing|
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