KR101008159B1 - Method for Refining Low Carbon Molten Steel - Google Patents

Method for Refining Low Carbon Molten Steel Download PDF

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KR101008159B1
KR101008159B1 KR1020030081203A KR20030081203A KR101008159B1 KR 101008159 B1 KR101008159 B1 KR 101008159B1 KR 1020030081203 A KR1020030081203 A KR 1020030081203A KR 20030081203 A KR20030081203 A KR 20030081203A KR 101008159 B1 KR101008159 B1 KR 101008159B1
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carbon
molten steel
refining
steel
degassing
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KR1020030081203A
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Korean (ko)
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KR20050047383A (en
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최학인
김재열
김영준
권기훈
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주식회사 포스코
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04Removing impurities by adding a treating agent
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10Handling in a vacuum
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/0025Charging or loading melting furnaces with material in the solid state
    • F27D3/0026Introducing additives into the melt
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00Arrangements of controlling devices
    • F27D2019/0003Monitoring the temperature or a characteristic of the charge and using it as a controlling value

Abstract

본 발명은 저탄소용강을 정련하는 방법에 관한 것으로서, 저탄소용강을 RH탈가스처리함에 있어서 RH탈가스공정의 탈산단계전에 Fe-Mn을 투입함으로써 슬래그중 [P]가 용강으로 이동하는 복인현상을 방지할 수 있을 뿐만 아니라 제조원가를 낮출 수 있는 저탄소강의 정련방법을 제공하고자 하는데, 그 목적이 있는 것이다.The present invention relates to a method for refining low carbon molten steel, wherein in the RH degassing treatment, Fe-Mn is added prior to the deoxidation step of the RH degassing process to prevent the compounding phenomenon in which [P] moves to molten steel. To provide a refining method of low carbon steel that can not only reduce the manufacturing cost, but its purpose is to.

본 발명은 저탄소용강 정련방법에 있어서, 전로종점 탄소함량을 측정하고;The present invention relates to a low carbon steel refining method, comprising: measuring the converter end point carbon content;

측정된 전로종점 탄소함량이 0.026중량%미만인 경우에는 RH탈가스공정의 탈산단계전에 고탄소 Fe-Mn을 투입하고; If the measured end point carbon content is less than 0.026% by weight, high carbon Fe—Mn is added before the deoxidation step of the RH degassing process;

그리고 측정된 전로종점 탄소함량이 0.026중량%이상인 경우에는 출강중에 Al 합금철 및 Fe-Mn을 투입하지 않고, RH탈가스공정의 탈산단계전에 고탄소 Fe-Mn을 투입하는 것을 특징으로 하는 저탄소용강의 정련방법을 그 요지로 한다.And when the measured end point carbon content is more than 0.026% by weight, the low-carbon molten steel, characterized in that the high-carbon Fe-Mn is added before the deoxidation step of the RH degassing process without adding Al alloy iron and Fe-Mn during tapping. The method of refining is to the point.

용강, 정련, 고탄소 Fe-Mn, 저탄소강, 탈가스, 복린Molten steel, Refinery, High carbon Fe-Mn, Low carbon steel, Degassing, Boklin

Description

저탄소용강의 정련방법{Method for Refining Low Carbon Molten Steel}Method for Refining Low Carbon Molten Steel

도 1은 통상적인 제강공정을 나타내는 공정도 1 is a process chart showing a conventional steelmaking process

도 2는 통상적인 전로공정을 나타내는 개략도로서, 2 is a schematic view showing a conventional converter process,

(a)는 전로 취련공정을 나타내고, 그리고 (b)는 전로 출강작업을 나타내는 것임(a) shows the converter blowing process, and (b) shows the converter lifting work.

도 3은 통상적인 RH 탈가스장치를 나타내는 개략도3 is a schematic view showing a conventional RH degassing apparatus

도 4는 종래방법에 따라 저탄소강을 탈가스처리하는 과정을 나타내는 작업처리도Figure 4 is a work process diagram showing a process of degassing the low carbon steel according to the conventional method

* 도면의 주요부분에 대한 부호의 설명 *Explanation of symbols on the main parts of the drawings

20 . . . 전로 21 . . . 산소랜스 40 . . . 탈가스장치 20. . . Converter 21. . . Oxygen lance 40. . . Degassing Equipment

41 . . . 진공조 41. . . Vacuum

본 발명은 저탄소용강을 정련하는 방법에 관한 것으로서, 보다 상세하게는 슬래그중의 [P]로 인한 복[P]를 방지할 수 있는 저탄소용강의 정련방법에 관한 것이다.The present invention relates to a method for refining low carbon molten steel, and more particularly, to a method for refining low carbon molten steel that can prevent abdominal [P] caused by [P] in slag.

일반적으로 강 제품은 도 1에 나타낸 바와 같이 용광로(10)에서 철광석을 용융한 후, 용선을 전로(20)에 장입하여 1차적인 정련을 행하고 래들(30)로 출강한 다음, 출강된 용강을 RH탈가스장치(40)로 이송하여 2차 정련을 행한 후, 연주기(50)에서 연속주조함으로써 제조된다.In general, steel products are molten iron ore in the furnace 10, as shown in Figure 1, the molten iron is charged into the converter 20 to perform the primary refining and tapping into the ladle (30), and then the molten steel After the secondary refining is carried out by transferring to the RH degassing apparatus 40, it is produced by continuous casting in the player 50.

저탄소강은 용강중의 탄소함량이 0.02~0.05%정도인 강을 말하며, 이러한 저탄소강을 제조하기 위해서는 전로공정에서 강종의 목표 성분치에 따라 합금철이 투입되고, 강의 청정성을 확보하기 위해 탈가스공정을 반드시 경유한 후, 연주공정으로 이송되어져 주조작업을 행하여야 한다.Low carbon steel refers to steel with a carbon content of about 0.02 to 0.05% in molten steel.In order to manufacture such low carbon steel, ferroalloy is introduced according to the target component value of the steel grade in the converter process, and degassing is performed to secure the steel. After passing it through, it should be transferred to the playing process and casted.

상기 전로에서는 도 2(a)에 나타난 바와 같이 전로 내에 용선과 고철을 장입하고, 산소랜스(21)를 통해 산소를 취입하여 용강을 정련하게 되며 이에 따라 용강 중 산소는 약 400~900ppm정도 다량 함유하게 된다. In the converter, as shown in FIG. 2 (a), molten iron and scrap metal are charged into the converter, and oxygen is blown through the oxygen lance 21 to refine the molten steel. Accordingly, oxygen in the molten steel contains about 400 to 900 ppm. Done.

한편, 전로 종점 탄소함량이 0.026%미만인 강종에 대해서는 전로 출강작업 중 탈산작업을 실시하지 않는 출강법을 경처리 출강법이라고 한다. On the other hand, for steel grades with less than 0.026% of the final carbon of the converter, the tapping method that does not perform deoxidation during tapping is called hard treatment tapping method.

또한, 전로 종점 탄소함량이 0.026% 이상인 강종에 대해서는 전로 출강작업 중 Al을 투입하여 강중 산소를 제거하는 탈산 작업을 하는데 이러한 출강법을 중처리 출강법이라고 한다. In addition, for steel grades with a carbon content of 0.026% or more, the deoxidation work to remove oxygen in the steel by adding Al during the converter tapping work is called a heavy treatment tapping method.

즉, 전로에서 출강하는 과정에서 강종 목표 성분치를 조정하기 위해서 강중 산소에 따른 Al 탈산과 도 2(b)에 나타난 바와 같이 합금철인 Fe-Mn등을 투입한다.That is, in order to adjust the steel grade target component value during the step out of the converter, Al deoxidation according to the oxygen in the steel and Fe-Mn, which is ferroalloy as shown in FIG.

상기와 같이 전로 출강작업이 끝나면 용강 품질의 청정성을 확보하기 위해 용강중 화학성분 미세조정 및 비금속 개재물 분리부상, 온도 균일화 목적으로 탈가스처리를 하게 된다.After finishing the converter tapping work as described above, in order to secure the cleanliness of the molten steel, fine gas adjustment of the molten steel, separation of nonmetallic inclusions, and degassing are performed for the purpose of temperature uniformity.

탈가스처리공정에서는 도 3에 나타난 바와 같이 진공조(41)을 이용하여 용강을 환 류시키고, 이때 연속주조작업에 적합한 온도로 조정하기 위해 냉각 및 승온 작업을 병행해야 한다. In the degassing process, as shown in FIG. 3, the molten steel is refluxed using the vacuum tank 41, and in this case, cooling and heating operations must be performed in parallel to adjust the temperature to a temperature suitable for continuous casting.

도 3에서 부호 42는 "탑랜스"를 나타내고, 부호 43은 "상승관"을 나타내고, 그리고 부호 44는 "하강관"을 나타낸다. In Fig. 3, reference numeral 42 denotes "top lance", reference numeral 43 denotes "rising pipe", and reference numeral 44 denotes "down pipe".

저탄소강의 탈가스처리공정의 일례가 도 4에 나타나 있다.An example of the degassing process of low carbon steel is shown in FIG.

즉, 탈가스처리 2분 정도인 진공도 250~150m Bar에 선행 합금철이 투입되거나 일정시간 환류 후 측온 샘플링을 실시하여 용강을 대표하는 시료 및 온도, 산소를 측정하여 시료는 분석실로 발송하고 측정된 온도를 근거로 연속주조작업에 적합한 온도로 맞추기 위해 승온 또는 냉각작업을 병행 실시한다.In other words, pre-alloyed iron is put in a vacuum degree of 250 ~ 150m Bar, which is about 2 minutes of degassing, or measured for temperature measurement after reflux for a certain time to measure the sample representing the molten steel, temperature and oxygen, and then send the sample to the analysis chamber and measure the temperature. In order to adjust the temperature to a temperature suitable for continuous casting operation, the heating or cooling operation is performed in parallel.

그후 분석이 완료된 시료 성분치를 확인하여 합금철을 추가 투입하거나 측온샘플링을 실시하여 출발온도를 확인하고 탈가스처리작업을 마치게 된다. After that, the sample component value is analyzed and the ferroalloy is added or the temperature measurement is performed to confirm the starting temperature and to finish the degassing process.

그런데 이러한 저탄소강중 [P]성분이 0.017%이하 함유되어야 되는 강종을 처리하는 경우에는 전로 출강중 슬래그중의 [P]가 용강내로 픽업(Pick Up)되는 복[P]현상이 발생되어 출강된 용강을 전로로 다시 재 장입시키는 회송처리 또는 2차정련에서 강종 변경작업이 실시되는데, 이때, 탈가스공정은 강종변경에 따른 합금철사용이 많아지고 용강성분을 적어도 2~3개정도는 확인해야 되어 탈가스 처리시간이 지연되는 문제점이 있다.However, when processing the steel grade that [P] component should be contained 0.017% or less among the low carbon steels, molten steel that has been pulled out due to the phenomenon of [P] picking up in the molten steel during pick-up of the slag. Steel grade change work is carried out in the recirculation process or secondary refining process to reload the furnace into the converter.In this case, the degassing process requires the use of alloy steel according to the steel type change, and at least two or three molten steel components should be checked. There is a problem that the degassing treatment time is delayed.

본 발명자들은 상기한 종래기술의 문제점을 해결하기 위하여 연구 및 실험을 행하고, 그 결과에 근거하여 본 발명을 제안하게 된 것으로서, 본 발명은 저탄소용강을 RH탈가스처리함에 있어서 RH탈가스공정의 탈산단계전에 Fe-Mn을 투입함으로써 슬래그중 [P]가 용강으로 이동하는 복인현상을 방지할 수 있을 뿐만 아니라 제조원가를 낮출 수 있는 저탄소강의 정련방법을 제공하고자 하는데, 그 목적이 있는 것이다.The present inventors have conducted research and experiments to solve the above problems of the prior art, and based on the results, the present invention proposes the present invention, and the present invention deoxidizes the RH degassing process in the RH degassing treatment of low carbon molten steel. The purpose of the present invention is to provide a refining method of low carbon steel that can reduce the manufacturing cost of the slag [P] to the molten steel by the addition of Fe-Mn before the step.

이하, 본 발명에 대하여 설명한다.EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

본 발명은 전로정련한 후 래들로 출강한 다음, 출강된 용강을 RH탈가스공정에서 탈탄 및 탈산하는 2차정련공정을 통하여 저탄소용강을 정련하는 저탄소용강 정련방법에 있어서, The present invention is a low-carbon molten steel refining method for refining low-carbon molten steel through the secondary refining process of tapping the ladle after the refining the converter, and then decarburized and deoxidized the molten steel in the RH degassing process,

전로종점 탄소함량을 측정하고;Measuring the endpoint carbon content of the converter;

측정된 전로종점 탄소함량이 0.026중량%미만인 경우에는 RH탈가스공정의 탈산단계전에 고탄소 Fe-Mn을 투입하고; If the measured end point carbon content is less than 0.026% by weight, high carbon Fe—Mn is added before the deoxidation step of the RH degassing process;

그리고 측정된 전로종점 탄소함량이 0.026중량%이상인 경우에는 출강중에 Al 합금철 및 Fe-Mn을 투입하지 않고, RH탈가스공정의 탈산단계전에 고탄소 Fe-Mn을 투입하는 것을 특징으로 하는 저탄소용강의 정련방법에 관한 것이다.And when the measured end point carbon content is more than 0.026% by weight, the low-carbon molten steel, characterized in that the high-carbon Fe-Mn is added before the deoxidation step of the RH degassing process without adding Al alloy iron and Fe-Mn during tapping. It is about refining method.

이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.

본 발명은 전로정련한 후 래들로 출강한 다음, 출강된 용강을 RH탈가스공정에서 탈탄 및 탈산하는 2차정련공정을 통하여 저탄소용강을 정련하는 방법에 적용된다.The present invention is applied to a method for refining low-carbon molten steel through the secondary refining process of tapping the ladle and then tapping the ladle, and then decarburizing and deoxidizing the steel melted in the RH degassing process.

본 발명은 전로 종점 탄소함량이 0.026%미만인 경처리재 및 전로 종점 탄소함량이 0.026% 이상인 중처리재 모두에 적용되는 것이다. The present invention is applied to both the hardened material having a converter end point carbon content of less than 0.026% and the heavy treated material having a converter end point carbon content of 0.026% or more.                     

보다 바람직하게는, 본 발명은 탄소함량이 0.02~0.05%이고, 그리고 [P]함량이 0.017%이하인 저탄소 용강을 제조하기 위하여 정련하는 방법에 적용된다.More preferably, the present invention is applied to a method for refining to produce a low carbon molten steel having a carbon content of 0.02 to 0.05% and a [P] content of 0.017% or less.

본 발명의 주요특징은 전로출강중에 Al합금철 및 Fe-Mn을 투입하지 않고, 2차정련인 탈가스공정의 탈산전에 바람직하게는 탈가스 처리 개시후 4∼7분정도의 시점에서 고탄소 Fe-Mn을 투입하여 용강내 불순물을 분리부상시켜 줌으로써 슬래그중 [P]성분을 안정화로 복인(P)를 방지하면서 탈가스공정 처리시간도 안정화시키는데 있다.The main feature of the present invention is that high-carbon Fe is preferably added at about 4-7 minutes after the start of degassing treatment before deoxidation of the degassing process of secondary refining without adding Al alloy iron and Fe-Mn into the converter steel. By adding -Mn to separate and injure the impurities in the molten steel to stabilize the [P] component in the slag to prevent vane (P) while stabilizing the degassing process.

본 발명에서와 같이, 중처리재라 하더라도 전로 출강작업시 Al합금철 및 Fe-Mn을 투입하지 않고 출강하면 슬래그중 [P]가 용강내로 픽업이 되지 않으며, 이러한 상태로 탈가스공정으로 이송되며, 이때 [O] 및 [Mn]의 함량은 각각 250~450ppm 및 0.07~0.10%정도가 된다.As in the present invention, even if the heavy treatment material is pulled out without the addition of Al alloy iron and Fe-Mn during the converter tapping work [P] of the slag is not picked up into the molten steel, it is transferred to the degassing process in this state, At this time, the content of [O] and [Mn] is about 250 ~ 450ppm and 0.07 ~ 0.10% respectively.

일반적인 탈가스 작업의 원리를 설명하면 다음과 같다. The principle of general degassing operation is as follows.

도 3에 나타난 바와 같이, 상기 탈가스설비의 상승관(43)과 하강관(44)을 통해 래들 내 슬래그층을 뚫고 용강만을 환류시킴으로써 탈가스작업이 진행된다.As shown in Figure 3, the degassing operation is carried out by passing only the molten steel through the slag layer in the ladle through the rising pipe 43 and the down pipe 44 of the degassing facility.

탈산이 되지 않은 상태로 도착된 용강에 침적관을 침적시켜 진공조(41)를 통해 진공 65~80mbar를 형성시키면, 강중 [C]는 하기 반응식(1)과 같이 [O]와 반응하여 탈탄이 이루어지며, 또한, 하기 반응식(2)와 같은 복[P]현상, 즉 슬래그층에 포함된 P2O5가 용강속으로 픽업(Pick Up)되는 것을 막을 수 있다.When the deposition tube is deposited on the molten steel that is not deoxidized to form a vacuum 65 to 80 mbar through the vacuum chamber 41, the steel [C] reacts with [O] as shown in the following reaction formula (1) to decarburize. In addition, it is possible to prevent the pickup [P] phenomenon, such as the following reaction formula (2), that is, P 2 O 5 contained in the slag layer is picked up to the molten steel (Pick Up).

[반응식 1] Scheme 1                     

[C] + [O] = CO(g)[C] + [O] = CO (g)

[반응식 2]Scheme 2

{P2O5} = 2[P] + 5[O]{P 2 O 5 } = 2 [P] + 5 [O]

본 발명에 따라 RH탈가스공정의 탈산전에 투입되는 고탄소 Fe-Mn의 투입량은 350∼600kg/용강-280톤으로 설정하는 것이 바람직한데, 그 이유는 이 투입량의 범위를 벗어나는 경우에는 용강품질에 문제가 있기 때문이다.According to the present invention, the amount of high carbon Fe-Mn to be added before deoxidation in the RH degassing process is preferably set to 350 to 600 kg / melt-280 ton, because if it is out of the range, Because there is a problem.

또한, 상기 고탄소 Fe-Mn의 투입속도는 분당 120∼200kg/용강-280톤으로 설정하는 것이 바람직하다.In addition, the input rate of the high-carbon Fe-Mn is preferably set to 120 ~ 200kg / mol-280 tons per minute.

투입속도가 너무 느린 경우에는 처리시간이 지연되어 생산성이 떨어지는 문제가 있고, 너무 빠른 경우에는 급작스런 CO 반응이 발생하여 진공도가 헌팅되면서 용강비산에 문제가 있으므로, 고탄소 Fe-Mn의 투입속도는 분당 120∼200kg/용강-280톤으로 설정하는 것이 바람직하다.If the feed rate is too slow, there is a problem that the productivity is reduced due to delayed processing time, and if too fast, a sudden CO reaction occurs and there is a problem in molten steel scattering while the vacuum degree is hunted, so the feed rate of high-carbon Fe-Mn per minute It is preferable to set it to 120-200 kg / mold-280 tons.

종래 방법에서와 같이 탈산단계후에 Fe-Mn을 투입하는 것과는 달리 본 발명에서는 탈산단계전에 Fe-Mn을 투입하므로 저급인 고탄소 Fe-Mn의 사용을 가능하게 할 수 있다.Unlike Fe-Mn after the deoxidation step, as in the conventional method, Fe-Mn is added before the deoxidation step, thereby enabling the use of low-grade high carbon Fe-Mn.

본 발명에서 사용되는 저급의 고탄소 Fe-Mn은 특별히 한정되는 것은 아니지만, M n:73.5∼75.4% 및 C: 5.7∼6.9%로 이루어지는 저급의 고탄소 Fe-Mn이 바람직하게 사용될 수 있다.Limited to the lower used in the present invention is high carbon Fe-Mn, but not specifically, M n: 73.5~75.4% and C: lower a high carbon Fe-Mn formed of 5.7~6.9% in can preferably be used.

종래방법에서 사용되는 중탄소 Fe-Mn의 조성은 Mn:76.5∼78.2% 및 C: 1.5∼2.0%로 이루어져 있다.The composition of the medium carbon Fe-Mn used in the conventional method is Mn: 76.5 to 77.2% and C: 1.5 to 2.0%.

상기와 같이, Fe-Mn을 투입한 후 용강중의 산소의 함량을 측정하고, 측정된 결과에 근거하여 탈산단계에서 Al 합금철을 투입하여 탈산을 행하여 2차정련한다.As described above, after the Fe-Mn is added, the oxygen content in the molten steel is measured, and deoxidation is performed by adding Al alloy iron in the deoxidation step on the basis of the measured result, followed by secondary refining.

상기와 같이 2차 정련된 용강은 연속주조공정에서 연속주조된다.As described above, the secondary refined molten steel is continuously cast in a continuous casting process.

상기와 같이 Fe-Mn 및 Al합금철을 투입함으써, 복린을 최소화하여 전로종점에서의 인[P]의 함랑과 거의 동일한 인의 함량을 갖는 극저탄소용강을 보다 경제적으로 제조할 수 있다. By injecting Fe-Mn and Al alloy iron as described above, it is possible to more economically produce an ultra-low carbon molten steel having a phosphorus content almost the same as the phosphorus [P] in the converter end by minimizing the compound.

이하, 실시예를 통하여 본 발명을 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

(실시예)(Example)

전로에서 출강한 용강 (276.0~280.0t)을 이용하여 [C]0.02~0.05% ,[Mn]0.15~0.25%인 저탄소 용강을 준비하여 하기 표 1과 같은 조건으로 용강정련작업을 실시하였다.The molten steel (276.0 ~ 280.0t) stepped out of the converter was prepared a low carbon molten steel of [C] 0.02 ~ 0.05%, [Mn] 0.15 ~ 0.25% to perform a molten steel refining operation under the conditions shown in Table 1.

상기 용강중 일부는 종래법과 동일하게 전로 출강시 종점산소에 따른 Al탈산 및 [Mn]성분 보정용 중탄소 Fe-Mn 350~500kg을 투입하였고, 나머지 용강에 대해서는 본 발명과 동일하게 전로 출강중 함금철 투입을 하지 않고 탈가스공정에서 탈산전에 고탄소 Fe-Mn을 투입하여 탈가스 처리 7~8분경 편차가 적은 [C]성분을 얻어 Al탈산하고 가탄재를 투입하여 탈가스 처리작업을 실시하여 탄소함량이 0.02~ 0.05%인 저탄소용강을 제조하였으며,탈가스공정에서 소요되는 처리시간 및 [P]성분 거동을 측정하고, 그 결과를 하기 표 1에 나타내었다.
Some of the molten steel was added 350 ~ 500kg of heavy carbon Fe-Mn for the Al deoxidation and [Mn] component correction according to the end point oxygen when the converter is in the same manner as the conventional method, and the other molten steel in the same way as the present invention In the degassing process, high carbon Fe-Mn is added before deoxidation to obtain [C] component with less variation in degassing treatment in 7-8 minutes. Al deoxidation is performed and degassing is performed by adding charcoal. This low carbon molten steel of 0.02 ~ 0.05% was prepared, the treatment time and [P] component behavior required in the degassing process was measured, and the results are shown in Table 1 below.

Figure 112003043288204-pat00001
Figure 112003043288204-pat00001

상기 표 1에 나타난 바와 같이, 본 발명법의 경우 탄소 함량이 0.02~0.05%인 저탄소강제조에 있어 탈가스처리시간이 안정되면서 [P]성분의 픽업(Pick Up)이 종래법에 비하여 우수함을 알 수 있다.
As shown in Table 1, the method of the present invention shows that the pick-up of the [P] component is superior to the conventional method while the degassing treatment time is stable in low carbon steel production having a carbon content of 0.02 to 0.05%. Can be.

상술한 바와 같이, 본 발명은 [C]가 0.02~0.05%인 저탄소강 정련시 실조업에 적용하면 슬래그중 [P]가 용강중으로 픽업되는 복[P]현상을 방지할 수 있어 강종 성분 범위를 초과하는 격외를 막을 수 있을 뿐만 아니라 용강중 [C]함유량을 일정하게 제어하면서 탈가스처리시간은 지연되지 않아 제강 물류흐름을 원활하게 할 수 있고, 또한 연주공정에 안정적인 용강을 공급할 수 있어 개재물 부상시간을 확보할 수 있으므로 품질도 항상시킬 수 있는 효과가 있는 것이다.As described above, the present invention can prevent the [P] phenomenon in which [P] in the slag is picked up in molten steel when applied to a low carbon steel refining industry in which [C] is 0.02 to 0.05%. It not only prevents excessive outflow, but also maintains constant [C] content in molten steel while degassing treatment time is not delayed, so that steelmaking flow can be smoothly flown, and stable molten steel can be supplied to the process of casting. Since it can be ensured that the quality is always effective.

또한, 본 발명은 탈산전에 Fe-Mn을 투입함으로써 Fe-Mn내의 불순물이 용강중 산소 와 반응하여 배가스로 방출 또는 슬래그 층으로 부상되어 용강중 [P]성분을 안정화시킬 수 있는 효과가 있는 것이다.In addition, the present invention is effective to stabilize the [P] component in the molten steel by introducing Fe-Mn before deoxidation, the impurities in the Fe-Mn react with the oxygen in the molten steel to be released as exhaust gas or floated in the slag layer.

Claims (2)

전로정련한 후 래들로 출강한 다음, 출강된 용강을 RH탈가스공정에서 탈탄 및 탈산하는 2차정련공정을 통하여 저탄소용강을 정련하는 저탄소용강 정련방법에 있어서, In the low-carbon molten steel refining method of refining the low-carbon molten steel through the secondary refining process of tapping the ladle after refining the converter and decarburizing and deoxidizing the molten steel in the RH degassing process, 전로종점 탄소함량을 측정하고;Measuring the endpoint carbon content of the converter; 측정된 전로종점 탄소함량이 0.026중량%미만인 경우에는 RH탈가스공정의 탈산단계전에 350∼600kg/용강-280톤의 고탄소 Fe-Mn을 투입하고; If the measured converter endpoint carbon content is less than 0.026% by weight, 350-600 kg / mol-steel-280 tons of high carbon Fe-Mn is added before the deoxidation step of the RH degassing process; 그리고 측정된 전로종점 탄소함량이 0.026중량%이상인 경우에는 출강중에 Al 합금철 및 Fe-Mn을 투입하지 않고, RH탈가스공정의 탈산단계전에 350∼600kg/용강-280톤의 고탄소 Fe-Mn을 투입하는 것을 특징으로 하는 저탄소용강의 정련방법When the measured end point carbon content is more than 0.026 wt%, Al alloy iron and Fe-Mn are not added during tapping, and 350 to 600 kg / mol-280 ton high carbon Fe-Mn is added before the deoxidation step of the RH degassing process. Refining method for low carbon molten steel, characterized in that the input 제1항에 있어서, 고탄소 Fe-Mn의 투입속도가 분당 120∼200kg/용강-280톤인 것을 특징으로 하는 저탄소용강의 정련방법The method of refining low-carbon molten steel according to claim 1, wherein the high-carbon Fe-Mn is introduced at a rate of 120 to 200 kg / mol-280 ton per minute.
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JPH01301815A (en) * 1988-05-30 1989-12-06 Sumitomo Metal Ind Ltd Smelting method of low carbon steel
KR900010219A (en) * 1988-12-22 1990-07-06 시끼 모리야 Coaxial starter
JPH10219337A (en) 1997-01-31 1998-08-18 Nkk Corp Method for smelting high clean steel
KR100476806B1 (en) 2000-06-15 2005-03-16 주식회사 포스코 A method for manufacturing extra low carbon steel

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01301815A (en) * 1988-05-30 1989-12-06 Sumitomo Metal Ind Ltd Smelting method of low carbon steel
KR900010219A (en) * 1988-12-22 1990-07-06 시끼 모리야 Coaxial starter
JPH10219337A (en) 1997-01-31 1998-08-18 Nkk Corp Method for smelting high clean steel
KR100476806B1 (en) 2000-06-15 2005-03-16 주식회사 포스코 A method for manufacturing extra low carbon steel

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