KR20000009058A - Inhibiting method of slopping during oxygen blowing in converter - Google Patents

Inhibiting method of slopping during oxygen blowing in converter Download PDF

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Publication number
KR20000009058A
KR20000009058A KR1019980029227A KR19980029227A KR20000009058A KR 20000009058 A KR20000009058 A KR 20000009058A KR 1019980029227 A KR1019980029227 A KR 1019980029227A KR 19980029227 A KR19980029227 A KR 19980029227A KR 20000009058 A KR20000009058 A KR 20000009058A
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stage
lance
minutes
converter
height
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KR1019980029227A
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Korean (ko)
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KR100354298B1 (en
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손호상
김정식
이정모
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이구택
포항종합제철 주식회사
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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
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • C21C5/32Blowing from above
    • 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
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/42Constructional features of converters
    • C21C5/46Details or accessories
    • C21C5/4606Lances or injectors
    • C21C5/462Means for handling, e.g. adjusting, changing, coupling
    • 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
    • F27D21/00Arrangement of monitoring devices; Arrangement of safety devices
    • F27D2021/0057Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

PURPOSE: An inhibiting method of a slopping during oxygen blowing process in a converter is provided which reduces the generation rate of the slopping by about 45% and improves the error rate of a steel tapping. CONSTITUTION: The process comprises six stages as follows:i)First stage, a low power of agitation is induced to maintain the speed of oxygen flow and the height of the lance constant for 4 min. after beginning of blowing oxygen in the converter ii)Second stage, a higher power of agitation than the first stage is induced to lower the height of the lance and maintain the same speed of oxygen flow as the first stage for 1 min. after the first stage iii) Third stage, a lower power of agitation than the first stage is induced to maintain the height of the lance of the second stage and reduce the speed of oxygen flow of the second stage for 4 min. after the second stage iv) Fourth stage, a higher power of agitation than the third stage is induced to lower the height of the lance and maintain the same speed of oxygen flow as the third stage for 1 min. after the third stage v) Fifth stage, a higher power of agitation than the fourth stage is induced to maintain the height of the lance of the fourth stage and increase the speed of oxygen flow for 5 min. after the fourth stage iv) Sixth stage, a lower power of agitation than the fifth stage is induced to maintain the height of the lance of the fifth stage and reduce the speed of oxygen flow of the fifth stage after the end of the fifth stage.

Description

전로취련중 슬로핑억제방법Slope suppression method during converter

본 발명은 전로취련중 슬로핑억제방법에 관한 것으로, 특히 전로작업시 로내의 슬래그와 용철의 효율적인 반응을 유도하기 위한 취련중 랜스높이와 송산유량을 다단계로 제어함으로써 슬로핑현상을 억제하는 전로취련중 슬로핑억제방법에 관한 것이다.The present invention relates to a method for suppressing slipping during converter blow, and in particular, a converter blow suppressing the dropping phenomenon by controlling the lance height and the flow rate during the blow in order to induce an efficient reaction between slag and molten iron in the converter. The present invention relates to an anti-slope method.

일반적으로, 전로조업에서는 주원료인 용선과 고철을 전로에 장입한 후, 산소를 불어넣어 용선중의 탄소, 규소, 망간, 인, 유황, 티탄 등의 불순원소를 산화제거하게 된다.In general, in the converter operation, the main raw materials, molten iron and scrap metal are charged into the converter, and oxygen is blown to oxidize and remove impurities such as carbon, silicon, manganese, phosphorus, sulfur, and titanium in the molten iron.

이때, 불순원소의 안정적 제거를 위하여 슬래그가 필요하며, 이는 취련중 투입하는 부원료(생석회, 형석, 백운석, 소결광 등)에 의하여 소정의 용강을 제조한다.At this time, slag is required for the stable removal of the impurity element, which produces a predetermined molten steel by using subsidiary materials (quick lime, fluorite, dolomite, sintered ore) which are injected during the drilling.

그리고, 전로에 장입되는 용선은 일반적으로 탄소함량이 4.5중량%이나 산소를 불어 넣으면 탄소함량이 0.05중량% 전후의 용강이 제조된다.In the molten iron charged into the converter, molten steel having a carbon content of about 0.05 wt% is generally produced when the carbon content is 4.5 wt% but oxygen is blown.

또한, 용선중에는 약0.4중량%의 규소와 함께 약0.1중량% 전후의 인을 함유하고 있으며, 송산과 더불어 우선적으로 규소가 산화되고 뒤이어 망간, 인 등이 산화되고, 산화되어 생성된 인화합물은 불안정하기 때문에 투입된 생석회와 반응시켜 안정된 산화물의 형태로 슬래그화하여 제거한다.In addition, the molten iron contains about 0.4% by weight of silicon and about 0.1% by weight of phosphorus, and together with the acid, silicon is preferentially oxidized, followed by oxidizing manganese, phosphorus, etc. Therefore, it is reacted with the added quicklime and slag is removed in the form of a stable oxide.

따라서, 용선중 규소는 취련중 슬래그 생성량과 비례하며, 용선중 규소농도가 높을 경우에는 슬래그량 과다로 취련중 슬래그가 로구 밖으로 분출되는 현상이 발생된다.Therefore, silicon in molten iron is proportional to slag generation in the molten iron, and when the silicon concentration in molten iron is high, the slag is blown out of the furnace due to the excessive slag amount.

한편, 전로에서의 취련작업은 고속의 산소가스가 랜스를 통하여 로내의 용철 및 슬래그에 고속으로 분사하는 것으로, 슬래그나 용철이 로구밖으로 튀어나오는 현상이 발생되는데, 이를 슬로핑(Slopping)이라 부른다.On the other hand, the blow job in the converter is a high-speed oxygen gas is injected at a high speed to the molten iron and slag in the furnace through the lance, the phenomenon occurs that the slag or molten iron springs out of the furnace, this is called the "slopping" (Slopping).

이때, 슬로핑의 발생원인으로는 용철 내부에 분사된 산소와, 용철중의 탄소가 반응하여 발생한 일산화탄소 등 반응가스가 용철상부의 슬래그층을 빠져나가지 못하고 거품과 같이 되어 슬래그층을 밀어올려서 결국에는 전로의 로구밖으로 분출되거나 슬래그량이 과다한 상태에서 과도한 교반이 일어날 경우에 발생한다.At this time, as a cause of the slope, the reaction gas such as oxygen injected into the molten iron and carbon monoxide generated by the reaction of carbon in the molten iron does not escape the slag layer on the upper side of the molten iron, and becomes a bubble, thereby pushing up the slag layer. Occurs when excessive agitation occurs in the state of ejection out of the furnace or excessive slag.

여기서, 100톤 전로의 경우, 이러한 현상은 취련 약 5분경 또는 12분경에 주로 발생되며, 이러한 슬로핑 발생시 슬래그중의 철분이 손실될 뿐만 아니라 용철까지 분출되면서 출강 실수율이 저하된다.Here, in the case of a 100 ton converter, this phenomenon is mainly generated at about 5 minutes or about 12 minutes of blowing, and when such a slope occurs, not only the iron in the slag is lost but also the molten iron is ejected, and the falling error rate decreases.

이로 인하여, 전로 정련작업의 원래 목적을 달성하기 위하여 분출된 슬래그량을 보충해야만 하고, 이로써 원가적인 손해뿐만 아니라 고온의 슬래그가 로외로 비산하므로 작업상 매우 위험하며, 대기환경을 오염 시키게 된다.Because of this, in order to achieve the original purpose of the converter refining operation, the amount of slag ejected must be replenished, and thus, as well as costly damage, the hot slag is scattered outside the furnace, which is very dangerous in operation and pollutes the air environment.

종래에는 이러한 슬로핑을 방지하기 위하여 우선적으로, 슬로핑 발생을 예측하기 위한 여러가지 방법이 제안되어 사용되고 있는데, 슬로핑 예측방법에는 가스 분석법, 랜스 진동 감지법, 음파법 등이 있으나, 설치하는데 많은 비용이 소요될 뿐만 아니라 고온의 열악한 환경에서 장치 유지보수가 힘들며, 무엇보다도 슬로핑은 순간적으로 일어나기 때문에 완전한 억제는 불가능한 것으로 알려져 있다.Conventionally, in order to prevent such a slope, various methods for predicting the occurrence of the slope have been proposed and used. The slope prediction method includes a gas analysis method, a lance vibration detection method, a sound wave method, etc., but it is expensive to install. Not only is this required, it is known that device maintenance is difficult in high temperature and harsh environments, and above all, because slope is instantaneous, complete suppression is impossible.

그리고, 슬로핑이 발생하였을 때의 종래 대처방법으로는 폐펄프 등을 원료로 하여 제조된 슬래그 진정제를 투입하고 있으나 슬로핑이 발생한 후에 투입되기 때문에 슬로핑을 일시적으로 감소시킬 뿐, 발생 그 자체는 방지하지 못하고 있다.In addition, as a conventional countermeasure when slope occurs, a slag sedative prepared using waste pulp or the like is added. However, since the slope is introduced after the occurrence of the slope, the slope is temporarily reduced, and the occurrence itself is reduced. It is not prevented.

또 다른 방법으로는 슬로핑이 발생하면 랜스를 하강시켜 순간적으로 용강 교반력 강화시키고 있으나 이 역시 이미 슬로핑이 발생한 후이기 때문에 경우에 따라서는 오히려 슬로핑을 조장하는 결과를 초래하기도 한다.In another method, when the slope occurs, the lance is lowered instantaneously to enhance the stirring force of the molten steel. However, since the slope is already generated, it may result in the promotion of the slope.

본 발명은 전로작업시 로내의 슬래그와 용철의 효율적인 반응을 유도하기 위한 취련중 로내의 슬래그 재화상태와 유동상황을 고려하여 랜스높이와 송산유량을 다단계로 제어함으로써 슬로핑현상을 억제하는 전로취련중 슬로핑억제방법을 제공함에 그 목적이 있다.The present invention is to control the height of lance and the flow rate in multiple stages in consideration of the slag ash state and flow conditions in the furnace to induce the efficient reaction of slag and molten iron in the furnace during the converter while suppressing the slope phenomenon It is an object of the present invention to provide a method for suppressing a slipping.

도1은 전로의 취련상태를 나타내는 측단면도Figure 1 is a side cross-sectional view showing the blowing state of the converter

도2는 종래의 취련패턴를 나타내는 그래프,2 is a graph showing a conventional blown pattern;

도3는 본 발명에 따른 취련패턴의 실시예를 나타내는 그래프,3 is a graph showing an embodiment of a blow pattern according to the present invention;

도4는 종래의 취련패턴 및 본 발명의 취련패턴을 적용한 경우의 슬로핑 발생율을 나타내는 그래프이다.4 is a graph showing the incidence of slopes when the conventional blowing pattern and the blowing pattern of the present invention are applied.

<도면에 사용된 부호의 설명><Description of Symbols Used in Drawings>

1: 전로 2: 랜스 3: 서브랜스 4: 용철 5: 슬래그1: converter 2: lance 3: sub-lance 4: molten iron 5: slag

상기한 목적을 달성하기 위하여 본 발명은 전로취련 4분까지 송산속도와 랜스높이(h)를 일정하게 유지하여 약교반을 유도하는 제1단계와; 전로취련 4분에서 5분까지 제1단계의 송산속도를 그대로 유지한 상태에서 랜스높이(h)를 낮추어 제1단계보다 높은 교반력을 유도하는 제2단계와; 전로취련 5분에서 9분까지 제2단계의 랜스높이(h)를 그대로 유지한 상태에서 제2단계의 송산속도를 감소시켜 제1단계보다 낮은 교반력을 유도하는 제3단계와; 전로취련 9분에서 10분까지 제3단계의 송산속도를 그대로 유지한 상태에서 랜스높이(h)를 낮추어 제3단계보다 높은 교반력을 유도하는 제4단계와; 전로취련 10분에서 15분까지 제4단계의 랜스높이(h)를 그대로 유지한 상태에서 송산속도를 증가시켜 제4단계보다 높은 교반력을 유도하는 제5단계와; 전로취련 15분부터 제5단계의 랜스높이(h)를 그대로 유지한 상태에서 제5단계의 송산속도를 감소시켜 제5단계보다 낮은 교반력을 유도하는 제6단계로 구성되는 것을 특징으로 하는 전로취련중 슬로핑억제방법을 제공한다.In order to achieve the above object, the present invention provides a first step of inducing stirring by maintaining a constant transmission speed and lance height (h) up to four minutes before the converter; A second step of inducing a higher stirring force than the first step by lowering the lance height (h) in the state of maintaining the feeding speed of the first step from 4 minutes to 5 minutes; A third step of inducing a stirring force lower than the first step by reducing the transmission speed of the second step while maintaining the lance height h of the second step from 5 minutes to 9 minutes; A fourth step of lowering the lance height h in a state in which the transfer speed of the third step is maintained as it is from 9 minutes to 10 minutes to induce a higher stirring force than the third step; A fifth step of inducing higher agitation force than the fourth step by increasing the delivery speed while maintaining the lance height h of the fourth step for 10 to 15 minutes; The converter is composed of a sixth step of reducing the delivery speed of the fifth step to induce a lower stirring force than the fifth step while maintaining the lance height (h) of the fifth step from 15 minutes Provides a method of suppressing the slipping during the drilling.

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

도1에 도시한 바와 같이, 랜스(2)의 높이 h를 낮추면서 그 송산유량을 증가시키면 랜스로부터의 산소가스 젯트류에 의하여 용철표면에 형성되는 파임깊이(L)가 커지면서 교반이 심하게 되어 전로(1)에서의 탈탄속도가 빨라지게 된다.As shown in Fig. 1, when the flow rate is increased while lowering the height h of the lance 2, the pit depth L formed on the surface of the molten iron by the oxygen gas jets from the lance increases, causing agitation. The decarburization speed in (1) becomes faster.

그러나, 용철(4)의 탈탄속도가 너무 심하게 되면 랜스(2)에서 분사되는 산소가스의 힘이 전로(1)의 바닥까지 도달하여 내화물의 용손이 심하게 되고, 반대로 교반력이 너무 약하게 되면 용철중 철성분의 산화가 많아져서 슬래그 부피가 늘어나 슬로핑이 일어나게 된다.However, if the decarburization speed of the molten iron 4 becomes too severe, the force of oxygen gas injected from the lance 2 reaches the bottom of the converter 1, and the melting of refractory becomes severe. As the oxidation of iron increases, the slag volume increases, so that the slope occurs.

여기서, 로내의 용철에 가해지는 교반력의 척도는 랜스(2)의 산소가스에 의하여 욕면에 생성되는 파임(cavity)깊이(L)와 정지 상태의 욕면 깊이(Lo)의 비인 L/Lo값을 이용하고 있다.Here, the measure of the stirring force applied to the molten iron in the furnace is the L / Lo value which is the ratio of the cavity depth L generated in the bath surface by the oxygen gas of the lance 2 and the bath surface depth Lo in the stationary state. I use it.

일반적으로, L/Lo가 0.9 이상이 되면 강교반으로 분류되어 전로(1) 바닥부의 내화물 용손이 심하게 되고, L/Lo가 0.7 이하가 되면 약교반력으로 분류되어 취련시간이 길어지고 용철중 철성분의 산화가 심하여 슬래그량이 증가한다.In general, when L / Lo is 0.9 or more, it is classified as steel stirring, and the refractory loss of the bottom of the converter (1) becomes severe. When L / Lo is 0.7 or less, it is classified as a weak stirring force, and the blowing time is long and the iron component of molten iron is long. The oxidation of is severe and slag amount increases.

그러나, 실제 전로(1)에서 파임의 깊이 L을 실측하는 것은 매우 곤란하기 때문에 대부분 식(1)을 이용하여 추정 사용하고 있다.However, since it is very difficult to actually measure the depth L of the pits in the actual converter 1, most of them are estimated using equation (1).

L = Lhexp(-0.78h/Lh)L = L h exp (-0.78h / L h )

Lh= 63(kQ/nd)2/3[1]L h = 63 (kQ / nd) 2/3 [1]

단, h는 도1에 나타낸 정지탕면에서 랜스선단부까지의 높이, k는 랜스노즐에 따른 상수로서 단공노즐의 경우 1, 3공노즐의 경우 1.3이며, Q는 산소가스 유량, n은 랜스노즐의 공(孔)수를 나타내며, d는 랜스노즐의 직경을 나타낸다.Where h is the height from the stationary bath surface shown in FIG. 1 to the lance tip, k is the constant according to the lance nozzle, and is 1.3 for the single and three-hole nozzles, Q is the oxygen gas flow rate, and n is the lance nozzle. The number of voids is shown, and d is the diameter of the lance nozzle.

한편, 정지탕면 높이 Lo는 취련 전에 서브랜스(3)를 이용하여 측정한 Ls에서 전로(1) 바닥부의 용선계수를 감안하여 다음 식과 같이 구한다.On the other hand, the still water surface height Lo is calculated by the following equation in consideration of the molten iron coefficient of the bottom of the converter 1 at Ls measured using the sub lance 3 before the blow.

Lo= LS-Lb-Lr L o = L S -L b -L r

Lr=a×CH [2]Lr = a × CH [2]

단, Ls는 서브랜스에서 측정한 탕면높이, Lb는 서브랜스 측정 기준점에서 로체바닥까지의 높이로 일정하며, Lr은 로체의 철피바닥에서 로내부의 내화물 바닥까지의 높이로 로체수명(CH)증가에 따라 감소하며, a는 로체수명에 따른 내화물용손계수를 나타낸다.However, Ls is the height of the water surface measured in the sub lance, Lb is the height from the sub lance measurement reference point to the bottom of the furnace body, and Lr is the height from the bottom of the shell to the refractory floor in the furnace. It decreases as a, and a represents the refractory loss coefficient according to the life of the furnace.

따라서, 식[1]과 [2]로부터 교반력의 척도가 되는 L/Lo를 구할 수 있으며, L/Lo는 랜스높이 h와 송산유량 Q에 좌우됨을 알 수 있다.Therefore, L / Lo, which is a measure of agitation force, can be obtained from equations [1] and [2], and it can be seen that L / Lo depends on the lance height h and delivery flow rate Q.

한편, 전로취련은 탈탄 반응속도에 따라 3단계로 구분할 수 있는데, 제1단계는 용선중의 규소가 우선적으로 산화되는 도2에 도시한 바와 같이 취련6분까지의 시기로, 이때 망간 및 인도 일부 제거되고, 탈탄반응 속도는 서서히 증가해가게 된다.On the other hand, the converter blow can be divided into three stages according to the decarburization reaction rate, the first stage is a period of up to six minutes of blowing as shown in Figure 2 in which the silicon in the molten iron is preferentially oxidized, where manganese and part of India It is removed, and the decarburization rate gradually increases.

여기서, 제1단계에서는 산화된 규소가 생석회등의 부원료와 반응하여 슬래그로 재화되는 시기로 교반이 심하게 되면 슬래그 재화에 악영향을 미치게 되므로 일반적으로 약교반을 유지하게 된다.Here, in the first step, when the oxidized silicon reacts with the sub-raw materials such as quicklime and is aggravated into slag, the stirring is severely adversely affects the slag commodity, so that the stirring is generally maintained.

그리고, 제2단계는 탈탄반응이 왕성하게 일어나는 취련 15분까지의 시기로, 이때 전로에 공급된 산소는 거의 대부분이 탄소와 반응하게 되며, 산소 공급속도가 탈탄반응을 지배하게 된다.In the second stage, the decarburization reaction takes place up to 15 minutes of brittleness, when the oxygen supplied to the converter is mostly reacted with carbon, and the oxygen supply rate dominates the decarburization reaction.

또한, 취련 2단계의 초기에는 냉각제 및 고체산소로 공급되는 소결광에 의한 산소공급원을 고려하여 송산속도를 낮추었다가 취련 2단계의 중기 이후부터 다시 송산속도를 높이고 랜스를 낮추어 강교반을 유도하고 있다.In addition, in the beginning of the second stage of blowing, considering the oxygen supply source by the sintered ore supplied to the coolant and solid oxygen, the sending rate was lowered, and after the middle stage of the second stage of blowing, the sending rate was increased and the lance was lowered to induce steel stirring.

마지막으로, 취련 3단계에서는 탄소의 산화반응 속도는 감소하고 용철중 철분의 산화가 증가하는 시기로 교반이 반응속도를 좌우하는 단계이다.Finally, in the third stage of the blowing, the oxidation reaction rate of carbon decreases and the oxidation of iron in molten iron increases.

한편, 슬로핑은 대부분이 취련 1단계에서 2단계로 천이되는 시점과 취련 2단계의 중기에서 말기 사이의 소결광 공급이 끝나고 송산량이 증가하면서 랜스높이가 낮아지는 시점에서 발생하고 있다.On the other hand, the slope occurs most of the time when the transition from the first stage to the second stage of the blow and the sintered ore supply between the end of the middle stage and the end of the supply stage after the supply of sintered ore increases the lance height is lowered.

따라서, 이러한 탈탄반응에 따른 전로내 가스발생 상황과 슬래그 물성을 면밀히 검토하면 교반력을 적절하게 제어하는 것에 의하여 탄소의 산화반응에 의하여 발생한 가스를 원활하게 배출시켜 슬로핑을 억제시킬 수 있다.Therefore, when the gas generation situation and the slag physical properties of the decarburization reaction are closely examined, the gas generated by the oxidation reaction of carbon can be smoothly discharged by appropriately controlling the stirring force, thereby suppressing the slope.

즉, 취련 제1단계에서 2단계로 천이되는 시점에서는 탄소의 산화반응에 의한 일산화탄소 등의 배가스 발생량이 급격하게 증가하면서 미처 재화되지 못한 상태에서 점성이 높은 용철상부의 슬래그를 기포화시켜 로구 밖으로 밀어내게 된다.In other words, when the transition from the first stage to the second stage occurs, the flue gas generation amount such as carbon monoxide caused by the oxidation reaction of carbon is rapidly increased, and the slag of the highly viscous molten iron is bubbled and pushed out of the furnace in the unrefined state. To me.

이때, 본 발명에서는 도3에 도시한 바와 같이 취련초기에 슬래그 재화를 위하여 약교반을 하고 슬래그 재화가 어느정도 진행되고 규소의 산화반응이 끝나 배가스 발생량이 급격하게 증가하기 약 1분전에 랜스높이만 낮추어 강교반을 하게 되면 용철에 가해진 교반력이 슬래그층에도 영향을 미쳐서 슬래그층을 균일하게 교반시키면서 슬래그층에 포집되어 있던 취련 1단계에서 발생된 배가스를 원활하게 배출시키고, 동시에 탈탄 왕성기에 발생하는 다량의 배가스를 신속하게 배출할 수 있게 하여 슬로핑을 억제한다.At this time, in the present invention, as shown in Figure 3 at the beginning of the slag goods for the slag goods and the slag goods are proceeded to some extent and the oxidation reaction of silicon is finished, the lower the lance height only about one minute before the flue gas generation increases sharply When the steel is stirred, the stirring force applied to the molten iron also affects the slag layer, while uniformly stirring the slag layer, while smoothly discharging the flue gas generated in the first stage of the blow-up collected in the slag layer, and simultaneously generating a large amount of decarburization vigor Slope can be suppressed by allowing exhaust gas to be discharged quickly.

한편, 취련 2단계가 시작되면 도3에 도시한 바와 같이 냉각제 및 고체산소로서 소결광을 투입하므로 송산속도를 감소시켜 교반력을 낮춘다.On the other hand, when the two stages of blowing start, as shown in FIG. 3, the sintered ore as a coolant and solid oxygen is introduced, thereby reducing the feeding speed to lower the stirring power.

그리고, 취련 2단계의 중반이후에는 투입된 소결광에 의한 고체산소가 소모되고, 슬래그 재화가 충분히 이루어져 있으므로 취련시간 단축을 위하여 송산속도를 증가시키고 랜스높이는 낮추어 다시 교반력을 증가시키게 된다.In addition, after the middle of the two stages of the blowing, solid oxygen is consumed by the sintered ore injected, and the slag is sufficiently made, so that the feed rate is increased and the lance height is lowered to increase the stirring power in order to shorten the blowing time.

그러나, 이 시점에서는 부원료의 투입이 완료되어 슬래그량 역시 증가하였기 때문에 송산속도의 증가 및 랜스하강에 따른 급격한 교반력 증대에 의하여 순간적으로 슬래그가 분출되어 로밖으로 튀어나오게 된다.However, at this point, since the input of the raw materials is completed and the slag amount is also increased, the slag is ejected out of the furnace instantaneously due to the increase in the feed rate and the rapid increase of the stirring force due to the lowering of the lance.

따라서, 냉각제로 투입되는 소결광에 의한 고체산소의 공급이 완료된 후, 송산속도를 증가시키기 약 1분전에 미리 랜스를 하강시켜 일정수준으로 교반력을 높인후 고체산소가 소비된 시점에 송산량을 증가시켜 단계적으로 교반력을 증가시키면 순간적인 슬래그의 분출을 억제할 수 있다.Therefore, after the supply of solid oxygen by the sintered ore injected into the coolant is completed, the lance is lowered in advance about 1 minute before increasing the delivery rate to increase agitation power to a certain level, and then the amount of acid delivered is increased when the solid oxygen is consumed. Increasing the agitation force in steps to suppress the instantaneous ejection of slag.

즉, 본 발명에서는 종래의 3단계로 변하는 교반력을 로내의 상황에 맞추어 6단계의 다단계로 제어함으로써 슬로핑을 억제할 수 있다.That is, in the present invention, the slope can be suppressed by controlling the stirring force changing in the conventional three stages in six stages in accordance with the situation in the furnace.

이하, 실시예를 통해 본 발명을 더욱 상세히 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.

도2에 도시한 바와 같이 종래의 취련패턴은 송산속도와 랜스높이가 6분 및 12분에 동시에 변동하게 되어있다.As shown in Fig. 2, in the conventional blown pattern, the feeding speed and the lance height are simultaneously varied at 6 minutes and 12 minutes.

우선, 취련 1단계인 초기 6분간은 18500Nm3/H의 속도로 송산하여 용선중의 규소 등을 조기에 산화시키고 있으며, 취련 2단계의 중반까지의 6분-12분사이에는 냉각제로 공급되는 소결광에 의한 고체산소의 기여를 고려하여 송산속도를 16500 Nm3/H로 감소시킨 후, 말기에는 다시 18500Nm3/H의 속도으로 송산하고 있다.First, the first six minutes of the first stage of blowing is delivered at a rate of 18500 Nm 3 / H to oxidize silicon in the molten iron early, and the sintered ore is supplied as a coolant between 6 minutes and 12 minutes to the middle of the second stage of blowing. in consideration of the contribution of oxygen by solid it was reduced to a rate Songshan 16500 Nm 3 / H, the end there is again the speed of Songshan 18500Nm 3 / H.

그리고, 랜스높이 h는 초기에는 1900mm를 유지시켜 슬래그 재화를 촉진하고 말기에도 송산량 증가와 동시에 1700mm로 100mm를 하강시켜 급격한 교반을 유도하고 있다.In addition, the lance height h is to maintain the 1900mm initially to promote the slag goods, and at the end of the increase in the amount of transport, and at the same time lowering 100mm to 1700mm to induce rapid stirring.

이러한 취련시기별 L/Lo를 식[1] 및 식[2]로부터 계산하여 보면 도2에 나타낸 바와 같이 0.838→0.766→0.893으로 슬로핑이 다발하는 5분경에는 교반력의 변화가 없고 슬로핑이 발생한 후인 6분에는 오히려 약교반으로 슬로핑을 조장하는 역효과가 나타나고 있다.When the L / Lo for each blowing time was calculated from Equations [1] and [2], as shown in FIG. 2, the stirring force was changed at 0.838 → 0.766 → 0.893 and there was no change in agitation force. Six minutes after the occurrence, rather than agitation, there is an adverse effect of promoting the slope.

또한, 슬래그가 충분히 재화된 시점인 취련 12분에는 급격한 교반력 상승으로 순간적인 슬래그의 분출이 발생하고 있다.In addition, at 12 minutes of blowing time when the slag is fully regenerated, instantaneous slag jetting occurs due to a sudden increase in stirring power.

한편,. 본 발명의 취련패턴은 도3에 도시한 바와 같이 로내의 상황에 적합하게 랜스높이(h)와 송산속도를 조절하여 다단계 등의 산화반응이 우선적으로 일어나고 탄소의 산화반응속도는 상대적으로 낮기때문에 송산속도를 1900Nm3/H로 높여서 취련시간을 단축할 수 있도록 하였다.Meanwhile,. In the blowing pattern of the present invention, as shown in Fig. 3, the lance height (h) and the feeding rate are adjusted to suit the situation in the furnace, so that oxidation reactions such as multistage occurs preferentially and the oxidation reaction rate of carbon is relatively low. The speed was increased to 1900 Nm 3 / H to reduce the time for blowing.

따라서, 송산속도 변동시점을 1분 앞당겨 취련개시 5분 후에 소결광에 의하여 발생하는 고체산소 공급분을 고려하여 송산속도를 17500Nm3/H로 낮추었다.Therefore, the transfer rate was lowered to 1,500 Nm 3 / H in consideration of the solid oxygen supply generated by the sintered ore 5 minutes after the start of the drilling, 1 minute earlier.

그리고, 고체산소의 공급이 끝난 10분에는 다시 탈탄을 더욱 왕성하게 진행시키기 위하여 18500Nm3/H로 송산속도를 증가시키고 탈탄반응이 거의 완료된 취련 15분부터는 용강의 과산화를 방지하기 위하여 18000Nm3/H으로 송산속도를 낮추었다.And, 18000Nm to 10 minutes, supply of the solid-state oxygen over and increased again Songshan speed decarburization to 18500Nm 3 / H in order to proceed more vigorously and to prevent peroxidation of the molten steel Starting blow 15 minutes decarburization reaction is substantially complete, 3 / H The transmission rate was lowered.

이때, 랜스높이(h)는 초기의 1900mm에서 송산속도가 증가하기 1분 전인 취련 9분에 랜스를 다시 100mm하강시켜 1차적으로 교반력을 증가시킨 후, 송산속도를 증가시켜 단계적으로 교반력을 증대시켰다.At this time, the lance height (h) is lowered to 100mm at the ninth minute, which is one minute before the delivery speed increases from the initial 1900mm, and then the stirring force is increased by increasing the delivery speed step by step by increasing the stirring speed. Increased.

따라서, 취련시기별 L/Lo는 0.862→0.889→0.816→0.843→0.893→0.868의 6단계로 변화시켜 초기 슬로핑이 발생하기 전에 강교반으로 슬래층에 포집되어 있는 가스의 배출이 용이하도록 하였으며. 취련중기 슬로핑이 발생하는 시점에서는 교반력을 단계적으로 상승시켜 슬래그의 순간적인 분출을 방지하여 슬로핑을 억제할 수 있도록 하였다.Therefore, L / Lo for each time period was changed to 6 stages of 0.862 → 0.889 → 0.816 → 0.843 → 0.893 → 0.868 to facilitate the discharge of the gas trapped in the slab layer by steel stirring before the initial slope. At the time of sloughing during the blow, the stirring force was increased stepwise to prevent instantaneous ejection of the slag, thereby suppressing the slope.

한편, 도4는 종래의 취련패턴과 본발명의 취련패턴을 1개월간 각각 약 2200회 적용한 경우의 슬로핑 발생비율을 비교한 것이다.On the other hand, Figure 4 compares the occurrence rate of the slope when the conventional blow pattern and the blow pattern of the present invention is applied about 2200 times each month.

여기서, 본 발명의 경우 대형 및 중형 슬로핑은 전혀 발생하지 않았고 소형의 경우에도 약 0.2% 정도 낮게 발생하였다.Here, in the case of the present invention, the large and medium slopes did not occur at all, and even in the case of the small size, about 0.2% lower.

따라서, 전체적인 슬로핑 발생비율은 종래의 취련패턴에서는 약 1.12%였으나 본 발명의 취련패턴을 적용한 경우 0.62%로 약 45%가 감소하여 효과적인 슬로핑 억제가 가능함을 확인 하였다.Therefore, the overall slope generation rate was about 1.12% in the conventional blow pattern, but when applying the blow pattern of the present invention it was confirmed that the effective slope suppression can be reduced by about 45% to 0.62%.

본 발명은 전로작업시 로내의 슬래그와 용철의 효율적인 반응을 유도하기 위한 취련중 로내의 슬래그 재화상태와 유동상황을 고려하여 랜스높이와 송산유량을 다단계로 제어함으로써 슬로핑 발생율을 약 45% 감소시키고, 이로써 출강실수율 향상은 물론 대기환경 개선을 할 수 있는 효과를 제공하게 된다.The present invention reduces the incidence of slope by about 45% by controlling the lance height and the flow rate in multiple stages in consideration of the slag ash state and flow situation in the furnace to induce efficient reaction of slag and molten iron in the converter operation. As a result, the attendance rate is improved as well as the atmospheric environment.

Claims (1)

전로취련 4분까지 송산속도와 랜스높이(h)를 일정하게 유지하여 약교반을 유도하는 제1단계와;A first step of inducing the stirring by maintaining the transmission speed and the lance height (h) constant for up to four minutes during the conversion of the converter; 전로취련 4분에서 5분까지 제1단계의 송산속도를 그대로 유지한 상태에서 랜스높이(h)를 낮추어 제1단계보다 높은 교반력을 유도하는 제2단계와;A second step of inducing a higher stirring force than the first step by lowering the lance height (h) in the state of maintaining the feeding speed of the first step from 4 minutes to 5 minutes; 전로취련 5분에서 9분까지 제2단계의 랜스높이(h)를 그대로 유지한 상태에서 제2단계의 송산속도를 감소시켜 제1단계보다 낮은 교반력을 유도하는 제3단계와;A third step of inducing a stirring force lower than the first step by reducing the transmission speed of the second step while maintaining the lance height h of the second step from 5 minutes to 9 minutes; 전로취련 9분에서 10분까지 제3단계의 송산속도를 그대로 유지한 상태에서 랜스높이(h)를 낮추어 제3단계보다 높은 교반력을 유도하는 제4단계와;A fourth step of lowering the lance height h in a state in which the transfer speed of the third step is maintained as it is from 9 minutes to 10 minutes to induce a higher stirring force than the third step; 전로취련 10분에서 15분까지 제4단계의 랜스높이(h)를 그대로 유지한 상태에서 송산속도를 증가시켜 제4단계보다 높은 교반력을 유도하는 제5단계와;A fifth step of inducing higher agitation force than the fourth step by increasing the delivery speed while maintaining the lance height h of the fourth step for 10 to 15 minutes; 전로취련 15분부터 제5단계의 랜스높이(h)를 그대로 유지한 상태에서 제5단계의 송산속도를 감소시켜 제5단계보다 낮은 교반력을 유도하는 제6단계로 구성되는 것을 특징으로 하는 전로취련중 슬로핑억제방법.The converter is composed of a sixth step of reducing the delivery speed of the fifth step to induce a lower stirring force than the fifth step while maintaining the lance height (h) of the fifth step from 15 minutes Slope suppression method while blowing.
KR1019980029227A 1998-07-21 1998-07-21 A depression method of slopping during blowing period KR100354298B1 (en)

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KR100423420B1 (en) * 1999-09-27 2004-03-19 주식회사 포스코 A Method for Preventing Slopping during Converter Blowing
KR100728130B1 (en) 2005-12-07 2007-06-13 주식회사 포스코 Method for Refining Molten Steel in Converter

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