JPS5919170B2 - Molten steel refining method - Google Patents
Molten steel refining methodInfo
- Publication number
- JPS5919170B2 JPS5919170B2 JP53159187A JP15918778A JPS5919170B2 JP S5919170 B2 JPS5919170 B2 JP S5919170B2 JP 53159187 A JP53159187 A JP 53159187A JP 15918778 A JP15918778 A JP 15918778A JP S5919170 B2 JPS5919170 B2 JP S5919170B2
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- refining
- carbon powder
- slag
- content
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Description
【発明の詳細な説明】
本発明は溶鋼の精錬方法の改良に関し、アーク炉を用い
る精錬の電力原単位と生産能率の向上を目的とする。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for refining molten steel, and its purpose is to improve the electric power consumption and production efficiency of refining using an arc furnace.
合材から出発して所望の鋼を製造しようとする場合、ア
ーク炉では多大の電力の消費を要する。When attempting to manufacture a desired steel starting from composite material, an arc furnace requires a large amount of power consumption.
そこで、電力消費を軽減するため、材料の溶解に至るま
でに要する熱量の全部または一部を、電力によらずに供
給する努力がなされてぎた。Therefore, in order to reduce power consumption, efforts have been made to supply all or part of the heat required to melt the material without relying on electric power.
たとえば、炉内に装入したスクラップ原料を加熱炉から
出る高温の排ガスで予熱したり、オイルバーナーで加熱
することが行なわれている。For example, scrap raw materials charged into a furnace are preheated with high-temperature exhaust gas discharged from a heating furnace, or heated with an oil burner.
また、ある程度まで撫度が高まった材料に酸素ガスを吹
ぎつげて、発熱反応を起させることも試みられている。Attempts have also been made to cause an exothermic reaction by blowing oxygen gas onto a material that has reached a certain degree of roughness.
これらの努力により、合材からその溶は落ちに至るまで
の加熱に関する限り、電力消費をかなりの割合で低減す
ることができるが、溶解から出鋼に至るまでの電力消費
は減らせない。These efforts can reduce the power consumption to a considerable extent as far as heating the composite material until its melting is concerned, but the power consumption from melting to tapping cannot be reduced.
それゆえ、この段階での電力の節減が残る課題となって
いた。Therefore, reducing power consumption at this stage remained an issue.
本発明の目的は、この溶解から出鋼までの省エネルギー
を実現した精錬方法を提供することにある。An object of the present invention is to provide a refining method that achieves energy savings from melting to tapping.
一般に、アーク炉による溶鋼の精錬において電力原単位
を向上させるためには、精錬時間の短縮が必要である。Generally, in order to improve the electric power consumption in refining molten steel using an arc furnace, it is necessary to shorten the refining time.
時間の短縮は、いうまでもなく能率の向上をも結果する
から、その観点からも好ましい。Needless to say, shortening the time also results in improved efficiency, which is preferable from that point of view as well.
精錬時間を短縮するには、材料の溶は落ち後の精錬温度
への昇熱時間を短縮することが、もつとも効果的である
。In order to shorten the refining time, it is most effective to shorten the heating time to the refining temperature after the material has melted.
本発明者らは、この点に着目して研究を重ねた。The present inventors focused on this point and conducted repeated research.
まず、溶は落ち後の溶鋼中のC含有量が高くなるように
材料なえらんで溶解しhこれに酸素ブローを行なって昇
熱速度を高めることを企てたが、酸素ブロー後のC含有
量が安定せず、所望の精錬を行なうには不都合であるこ
とがわかった。First, we attempted to increase the heating rate by selecting and melting the material so that the C content in the molten steel would be high after the melt was blown with oxygen, but the C content after the oxygen blowing was It was found that the amount was not stable and it was inconvenient to perform the desired refining.
そこで、これとは逆に、酸素ブローを行なって速かに昇
温させるとともにC含有量を規格より低目にし、そこへ
炭素粉末を吹き込むことにより、C含有量のコントロー
ルと精錬時間の短縮をあわせ行なうことを意図し、成功
をみた。Therefore, on the contrary, we can control the C content and shorten the refining time by blowing oxygen to quickly raise the temperature and lowering the C content below the standard, and then blowing carbon powder into it. The intention was to do this together, and it was successful.
本発明はこの手法にもとづいている。The invention is based on this approach.
本発明による溶鋼の精錬方法は、アーク炉を用いて溶鋼
を精錬するに際して、炉内に装入した材料の溶は落ちを
促すために、および(または)溶は落ちたのちの昇温を
速かにするために酸素ブローを行ない、溶鋼中のC含有
量を規格値より低くし、ついで炉内の溶解物に炭素粉末
をキャリアガスの流れにのせて吹診込んで溶鋼表面にあ
るスラグ内に泡沫層を形成させ、このスラグの泡沫層で
アークを包み込むことにより熱効率を高めつつ精錬を行
なうことを特徴とする。The method for refining molten steel according to the present invention, when refining molten steel using an arc furnace, is designed to accelerate the melting of the material charged into the furnace and/or to speed up the temperature rise after the melting has finished. Oxygen blowing is performed to lower the C content in the molten steel below the standard value, and then carbon powder is blown into the melt in the furnace along with a flow of carrier gas to remove the slag on the surface of the molten steel. The slag is characterized by forming a foam layer and wrapping the arc in the foam layer of the slag to improve thermal efficiency while refining.
図面を参照して説明すれば、酸素ブローを終了した後の
アーク炉1内には溶鋼の層6とその上をおおう溶融した
スラグの層5があり、電極2と溶鋼6との間のアークに
より熱が供給されている。To explain with reference to the drawings, in the arc furnace 1 after oxygen blowing, there is a layer 6 of molten steel and a layer 5 of molten slag covering it, and the arc between the electrode 2 and the molten steel 6 is Heat is supplied by
図示してないタンクから供給されるキャリアガス、たと
えばアルゴンの流れに炭素粉末をのせて、先端を溶鋼中
に浸したランスパイプ3により溶鋼6中に導入する。Carbon powder is placed on a flow of carrier gas such as argon supplied from a tank (not shown) and introduced into the molten steel 6 through a lance pipe 3 whose tip is immersed in the molten steel.
導入されたキャリアガスと炭素粉末の流れは1分散して
溶鋼6中およびスラグ5中を浮上する。The flow of the introduced carrier gas and carbon powder is dispersed and floats in the molten steel 6 and the slag 5.
その間に炭素粉末は溶鋼、およびスラグ中に溶は込んで
そのC含有量を高めるとともに、その中の酸素とくに酸
化鉄中の酸素と反応してCOガスを生成する。During this time, the carbon powder melts into the molten steel and slag to increase its C content, and reacts with oxygen therein, particularly oxygen in iron oxide, to generate CO gas.
生成したCOガスは、もともと吹き込まれたキャリアガ
スに加わってガスの容積を増す。The generated CO gas adds to the originally blown carrier gas to increase the gas volume.
スラグの粘度が、適度の高さであれば、これらのガスの
気泡の浮上により泡沫層5Aが形成され、スラグ層5、
とくにその上部は盛り上がりアークの少なくとも一部を
含み込む。If the viscosity of the slag is appropriately high, a foam layer 5A is formed by the floating of these gas bubbles, and the slag layer 5,
In particular, its upper portion includes at least a portion of the raised arc.
好ましい条件下では電極下部のアーク発生部分を包み込
んで、アーク全体がスラグに包まれるに至る。Under favorable conditions, the slag envelops the arc-generating portion at the bottom of the electrode, and the entire arc becomes enveloped in slag.
スラグの泡沫は最上部で破れて消える一方で、下方から
絶えず浮上して(るガスによって補給されるから、常に
ある程度の高さの泡沫層5Aが維持される。While the slag foam breaks and disappears at the top, it is replenished by the gas that constantly floats up from below, so the foam layer 5A is always maintained at a certain level.
このような現象が起る結果、アークにより発生する熱は
、はとんど外部に放射されず、スラグを通して溶鋼に伝
えられる。As a result of this phenomenon, the heat generated by the arc is hardly radiated to the outside, but is transferred to the molten steel through the slag.
もちろん、泡沫状のスラグ自体も溶鋼表面からの熱の放
射を低減する保温効果をもつ。Of course, the foamy slag itself also has a heat-insulating effect that reduces heat radiation from the surface of the molten steel.
上述したところから容易に理解されるように、炭素粉末
とキャリアガスとの吹き込みの位置は、スラグの泡沫層
の形成によるアーク包み込みの効果を最大限に得る見地
から、電極の直下またはその近くとすべきである。As can be easily understood from the above, the carbon powder and carrier gas are injected directly under or near the electrode to maximize the effect of arc envelopment due to the formation of a foam layer of slag. Should.
また、吹き込みの深さは、溶鋼中のC含有量に従って変
化させる。Moreover, the depth of blowing is changed according to the C content in the molten steel.
すなわち、C含有量が精錬によって達成しようとする鋼
の規格からみて低い間は溶鋼層内とし、C含有量が所定
の値に達したときはスラグ層内に移して吹き込みを続行
する。That is, as long as the C content is low in terms of the steel specifications to be achieved by refining, it is kept in the molten steel layer, and when the C content reaches a predetermined value, it is moved to the slag layer and the injection is continued.
キャリアガスは精錬作業に関して実質上不活性であれば
よく、アルゴンはもちろん好適であるが、窒素も、その
吹ぎ込みによる鋼浴中の窒素含有量の増大が差し支えな
い限り使用できる。The carrier gas need only be substantially inert with respect to the refining operation; argon is of course preferred, but nitrogen can also be used as long as its blowing does not cause an increase in the nitrogen content in the steel bath.
キャリアガス中に酸素が入っていても、炭素粉末との混
合物が吹き込み操業条件において爆発限界外にあるなら
ば許容できるので、空気も使用可能である。Air can also be used, since oxygen in the carrier gas is acceptable provided that the mixture with the carbon powder is outside the explosive limits under blowing operating conditions.
スラグ泡沫層の適量の形成および維持にとって、最も重
要な因子は炭素粉末の吹き込み量である。The most important factor for forming and maintaining a suitable amount of slag foam layer is the amount of carbon powder injected.
適当な値は溶鋼トンあたり、0.3〜1.7 kg/m
in。A suitable value is 0.3 to 1.7 kg/m per ton of molten steel.
in.
の範囲内にある。is within the range of
その他の諸条件、すなわち炭素粉末の粒度、キャリアガ
スの圧力、使用量などは、当業者が、必要ならばわずか
な実験を行なうことによって、適宜決定し得るであろう
。Other conditions, ie, the particle size of the carbon powder, the pressure of the carrier gas, the amount used, etc., can be appropriately determined by those skilled in the art, if necessary, by performing a little experimentation.
上述した炭素粉末の吹き込み量を含めて、通常のサイズ
(約30トン)のアーク炉において代表的な値を示せば
、次のとおりである。Typical values for a normal size (approximately 30 tons) arc furnace, including the amount of carbon powder injected as described above, are as follows.
吹込み時間 溶は落ち後の昇熱期
炭素粉末の粒径 平均1+ut
吹込み量 30kg/min
キャリアガス アルゴン、
圧力1.2kg/crfL、
流量12801! /min
ランスパイプ 径25mm、カロライドパイプ1吹込
み角度30、
深さ30(1m(溶鋼中の場合)
スラグ泡沫層が効果的にアークを包み込み・熱効率を十
分に高めるためには、さらに、スラグ層の厚さ、その溶
融粘度、電極と溶鋼湯面との距離などにも配慮すべきで
ある。Blow time Particle size of carbon powder during heating up after melting down Average 1+ut Blow amount 30 kg/min Carrier gas Argon, pressure 1.2 kg/crfL, flow rate 12801! /min Lance pipe Diameter 25 mm, Caloride pipe 1 Blow angle 30, Depth 30 (1 m (in case of molten steel) Consideration should also be given to the thickness of the layer, its melt viscosity, and the distance between the electrode and the molten steel surface.
本発明によるときは、溶鋼の精錬と(に溶解後から本格
的精錬に至る温度上昇が急速に行なわれる。According to the present invention, the temperature rises rapidly from the time of refining of molten steel to the time of full-scale refining.
すなわち、上昇速度は従来10℃/min程度であった
ものが、本発明によれば20℃/min程度と倍加する
。That is, the rate of increase, which was conventionally about 10° C./min, is doubled to about 20° C./min according to the present invention.
こうした急速な昇温は、昇熱期における電力の加熱効率
が、従来は40チ程度であるのに対し、上記のように操
作すれば80係に倍増する結果、実現するものである。Such rapid temperature rise is achieved because the heating efficiency of electric power during the heating period, which is conventionally about 40 degrees, doubles to 80 degrees when operated as described above.
これは、タップ・ツー・タップの間隔をゆうに10分間
短縮させるに足りる向上である。This is an improvement sufficient to reduce the tap-to-tap interval by well over 10 minutes.
図面は本発明の実施態様を説明するためのものであって
、精錬時のアーク炉の縦断面を示す。
1・・・アーク炉、2・・・電極、3・・・ランスパイ
プ、5・・・溶融スラグ、5A・・・スラグ泡沫層、6
・・・溶鋼。The drawing is for explaining an embodiment of the present invention, and shows a longitudinal section of an arc furnace during refining. DESCRIPTION OF SYMBOLS 1... Arc furnace, 2... Electrode, 3... Lance pipe, 5... Molten slag, 5A... Slag foam layer, 6
...molten steel.
Claims (1)
ローを行なって速かに昇温させるとともに溶鋼中のC含
有量を規格値より低くし、ついで炉内の溶解物に炭素粉
末をキャリアガスの流れにのせて吹き込んで溶鋼表面に
あるスラグ内に泡沫層を形成させ、このスラグの泡沫層
でアークを包み込むことにより熱効率を高めつつ精錬を
行なうことを特徴とする溶鋼の精錬方法。 2 炭素粉末の吹き込みを電極の直下またはその付近に
おいて行なう特許請求の範囲第1項の精錬方法。 3 キャリアガスがアルゴンまたは窒素である特許請求
の範囲第1項の精錬方法。 4 炭素粉末の吹ぎ込みを、溶鋼のC含有量が所定の値
より低い間は溶鋼層内において焔い、所定の値に達した
とぎはスラブ層内に移して続行する特許請求の範囲第1
項の精錬方法。[Claims] 1. When refining molten steel using an arc furnace, oxygen blowing is performed to quickly raise the temperature and lower the C content in the molten steel below the standard value, and then the molten steel in the furnace is A method of refining molten steel characterized by blowing carbon powder along with a carrier gas flow to form a foam layer in the slag on the surface of the molten steel, and by enveloping the arc with the foam layer of the slag, refining is carried out while increasing thermal efficiency. Refining method. 2. The refining method according to claim 1, wherein the carbon powder is injected directly under or near the electrode. 3. The refining method according to claim 1, wherein the carrier gas is argon or nitrogen. 4. The injecting of carbon powder is continued in the molten steel layer while the C content of the molten steel is lower than a predetermined value, and when the carbon content reaches the predetermined value, the carbon powder is transferred to the slab layer and continued. 1
Section refining method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53159187A JPS5919170B2 (en) | 1978-12-26 | 1978-12-26 | Molten steel refining method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53159187A JPS5919170B2 (en) | 1978-12-26 | 1978-12-26 | Molten steel refining method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5589414A JPS5589414A (en) | 1980-07-07 |
JPS5919170B2 true JPS5919170B2 (en) | 1984-05-02 |
Family
ID=15688206
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP53159187A Expired JPS5919170B2 (en) | 1978-12-26 | 1978-12-26 | Molten steel refining method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5919170B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999054512A1 (en) * | 1997-02-19 | 1999-10-28 | Kawasaki Steel Corporation | Method of judging slag forming state in electric furnace steel production and method of operating electric furnace |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8509629D0 (en) * | 1985-04-15 | 1985-05-22 | British Steel Corp | Melting ferrous solids |
FR2634787B1 (en) * | 1988-08-01 | 1991-11-29 | Siderurgie Fse Inst Rech | PROCESS FOR OBTAINING A FOAMING SLAG IN AN ELECTRIC STEEL FURNACE |
LU90409B1 (en) * | 1999-06-25 | 2001-01-02 | Wurth Paul Sa | Proc-d- for optimizing the operation of an electric furnace of the - submerged arc- type |
KR100391909B1 (en) * | 1999-12-07 | 2003-07-16 | 주식회사 포스코 | A method for improving slag forming using the molten slag in the mini-mill process |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5343003A (en) * | 1976-09-30 | 1978-04-18 | Mitsubishi Heavy Ind Ltd | Arc furnace operating method |
-
1978
- 1978-12-26 JP JP53159187A patent/JPS5919170B2/en not_active Expired
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5343003A (en) * | 1976-09-30 | 1978-04-18 | Mitsubishi Heavy Ind Ltd | Arc furnace operating method |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999054512A1 (en) * | 1997-02-19 | 1999-10-28 | Kawasaki Steel Corporation | Method of judging slag forming state in electric furnace steel production and method of operating electric furnace |
Also Published As
Publication number | Publication date |
---|---|
JPS5589414A (en) | 1980-07-07 |
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