JPH0254889A - Operation of dc arc furnace - Google Patents

Operation of dc arc furnace

Info

Publication number
JPH0254889A
JPH0254889A JP63205802A JP20580288A JPH0254889A JP H0254889 A JPH0254889 A JP H0254889A JP 63205802 A JP63205802 A JP 63205802A JP 20580288 A JP20580288 A JP 20580288A JP H0254889 A JPH0254889 A JP H0254889A
Authority
JP
Japan
Prior art keywords
electrode
movable electrode
molten steel
smelting
refining
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.)
Granted
Application number
JP63205802A
Other languages
Japanese (ja)
Other versions
JP2641913B2 (en
Inventor
Norio Ao
範夫 青
Hiroshi Shimizu
洋 清水
Shoichi Takahashi
昭一 高橋
Toshimichi Maki
牧 敏道
Kinzo Okazaki
岡崎 金造
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fuji Electric Co Ltd
JFE Engineering Corp
Original Assignee
Fuji Electric Co Ltd
NKK Corp
Nippon Kokan Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fuji Electric Co Ltd, NKK Corp, Nippon Kokan Ltd filed Critical Fuji Electric Co Ltd
Priority to JP63205802A priority Critical patent/JP2641913B2/en
Publication of JPH0254889A publication Critical patent/JPH0254889A/en
Application granted granted Critical
Publication of JP2641913B2 publication Critical patent/JP2641913B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

Landscapes

  • Furnace Details (AREA)
  • Discharge Heating (AREA)

Abstract

PURPOSE:To highly improve the temperature up efficiency, reduce the refining electric power, shorten the refining time, further improve the stirring property of smelting and slag, and obtain a smelting having a desired temperature and component by stopping the voltage fixing control at the time of the temperature up and refining of smelting, and setting the position of a movable electrode to a determined optimum position. CONSTITUTION:In the temperature up and refining processes of smelting, a switch 24 is closed to the dotted line side automatically or manually to control the raising/ falling of a movable electrode 3, and the smelting contact position detection value l0 of the electrode 3 sent from an electrode position sensor 14 is taken and memorized in a position detecting circuit 42, and the detection value l0 is supplied to an electrode raising position calculating means 43. As an optimum raising value l is preliminarily determined from the position of the electrode 3 and the potential based on a desired arc current in the means 43, the value l is added to the detection value l0 to obtain an optimum electrode setting position l1, which is then supplied to a subtracter 44. In the subtracter 44, a deviation signal between the set position l1 and the current position is calculated, and a speed setting controller 25 is operated to make the reaction of slag metal satisfactory.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、直流アーク炉のnl#電極(アーク電極とも
呼ぶ)の位置制御を行う直流アーク炉の操業方法に係わ
り、特に溶融金属の昇温効率を向上させる直流アーク炉
の操業方法に関する。
DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of operating a DC arc furnace that controls the position of the nl# electrode (also called an arc electrode) of the DC arc furnace. This invention relates to a method of operating a DC arc furnace that improves thermal efficiency.

〔従来の技術〕[Conventional technology]

一般に、溶解原料である鉄屑等の固体金属(以下、スク
ラップと指称する)を溶解する場合、第4図(a)の如
くアーク炉1内にスクラップ2を装入した後可動電極3
を昇降制御しながら可動電極3と炉底″J5極4間に所
定の直流電圧を印加して可動電極先端からアークを発生
させてスクラップ2を溶解していく。そして、−回目装
入したスクラップ2が第4図(b)の如く充分に溶解す
ると+1irRアーク炉1内にスクラップ2を装入する
追装工程に入り、所定量の溶融金属(以下、溶鋼と指弥
する)5を確保する迄スクラップ装入工程(切裂工程)
から前記スクラップの追装工程を繰り返し、所定口の溶
鋼を得るべき最後の装入スクラッブ2が完全に溶解する
と第4図(C)の如く溶は落ちの状態となる。しかる後
、第4図(d)の如く溶鋼5の成分3S整を行うために
溶鋼5の昇温制御を行う精錬工程に入る。この精錬工程
を終えると溶n45の出鋼を行って操業を終了する。
Generally, when melting solid metal such as iron scraps (hereinafter referred to as scrap) that is a raw material for melting, scrap 2 is charged into an arc furnace 1 as shown in FIG. 4(a), and then the movable electrode 3
A predetermined DC voltage is applied between the movable electrode 3 and the J5 pole 4 at the bottom of the furnace while controlling the elevation of the movable electrode, and an arc is generated from the tip of the movable electrode to melt the scrap 2. When the scrap 2 is sufficiently melted as shown in FIG. 4(b), an additional loading process is started in which the scrap 2 is charged into the +1irR arc furnace 1, and a predetermined amount of molten metal (hereinafter referred to as molten steel) 5 is secured. Up to scrap charging process (cutting process)
The above-mentioned scrap charging process is repeated, and when the last charged scrub 2 to obtain a predetermined amount of molten steel is completely melted, the melt reaches a state as shown in FIG. 4(C). Thereafter, as shown in FIG. 4(d), a refining process is started in which the temperature of the molten steel 5 is controlled in order to adjust the composition 3S of the molten steel 5. After completing this refining process, molten N45 steel is tapped and the operation is completed.

中、6は炉蓋、7は炉壁水冷パネル、8はスラグである
Inside, 6 is a furnace lid, 7 is a water cooling panel on the furnace wall, and 8 is a slag.

しかして、従来、溶は落ち工程および精錬工程等で溶鋼
5の昇lHを行う場合、交流アーク炉では予め電圧およ
び電流を設定し、画電極3,4間の発生電圧およびアー
ク電流が前記設定電圧および設定電流になるように可動
電極3を昇降制御しながら可動電極3からショートアー
クを発生して溶鋼上のスラグ8の厚みを増やし、可動電
極3先端からのアークをスラグ8内に突っ込むようにし
てスラグ8を泡立てる。いわゆるサブマージ操業を行っ
ている。従って、この交流アーク炉ではスラグ厚さとi
■動電極3のアーク長との関係から上記電圧および電流
が設定され、専らアーク電圧一定制御を行う方法である
Conventionally, when raising the molten steel 5 in the dropping process, refining process, etc., the voltage and current are set in advance in the AC arc furnace, and the voltage and arc current generated between the picture electrodes 3 and 4 are set as described above. While controlling the movable electrode 3 to move up and down so that the voltage and current are the same, a short arc is generated from the movable electrode 3 to increase the thickness of the slag 8 on the molten steel, and the arc from the tip of the movable electrode 3 is thrust into the slag 8. and whisk slag 8. We are conducting so-called submerged operations. Therefore, in this AC arc furnace, the slag thickness and i
(2) The above voltage and current are set based on the relationship with the arc length of the moving electrode 3, and this is a method that exclusively controls the arc voltage to be constant.

ところで、直流アーク炉において可動電極位置と電圧と
の関係を調べた結果、数10KA以−Lの大電流アーク
では、常に第5図に示すような特性パターンとなること
が見い出された。同図において横軸は電極位置ノg1縦
軸は両電極間発生電圧Vである。そこで、以上のような
特性パターンについて種々実験検討を重ねた結果、電極
位置I!gと溶鋼面5a、  スラグ而8aとは第6図
のような位置関係にあることか分った。なお、第5図お
よび第6図の■〜■はそれぞれ対応関係にある。そのう
ち、■−■間は可動電極3のアークジェットによって急
速に溶鋼面5aがへこみ、その時間オーダは1秒程度と
なる。このときの電極、1−昇距離は50mm程度とな
る。
By the way, as a result of investigating the relationship between the movable electrode position and voltage in a DC arc furnace, it was found that a large current arc of several tens of KA or more always has a characteristic pattern as shown in FIG. In the figure, the horizontal axis represents the electrode position g1, and the vertical axis represents the voltage V generated between both electrodes. Therefore, as a result of various experimental studies regarding the above characteristic patterns, the electrode position I! It was found that the positional relationship between g, molten steel surface 5a, and slag surface 8a is as shown in Fig. 6. Note that ■ to ■ in FIGS. 5 and 6 correspond to each other. During the period between ■ and ■, the molten steel surface 5a is rapidly depressed by the arc jet of the movable electrode 3, and the time period is on the order of one second. The electrode 1-elevation distance at this time is about 50 mm.

一方、■−■間ではアークジェットによる溶鋼5のへこ
みのために可動電極3を引I−げろと、この電極1.昇
と溶鋼面5aのへこみの減少とが相殺されて可動電極3
を引き」二げてもアーク長が伸びず、かつ、溶鋼へこみ
が小さくなるために発生電圧が高くならず専ら溶鋼へこ
みの変動で電圧変動だけか生ずる現象となる。そこで、
この■−■間において溶鋼5.可動電極位置igおよび
アーク等め関係を考慮しつつ昇温熱効率やスラグメタル
反応等について検討すると、0〜0間の電圧変化域での
電極位置制御よりも■−■間、特に■近傍での電極位置
制御の方が良好であることが分った。
On the other hand, between ■ and ■, the movable electrode 3 is pulled due to the dent in the molten steel 5 caused by the arc jet, and this electrode 1. The movable electrode 3 is offset by the increase in the height and the decrease in the dent in the molten steel surface 5a.
Even if the molten steel is pulled back, the arc length does not increase and the dent in the molten steel becomes smaller, so the generated voltage does not increase, and only voltage fluctuations occur due to fluctuations in the dent in the molten steel. Therefore,
Between this ■ and ■, the molten steel 5. Considering the movable electrode position ig and the arc equalization relationship, and considering heating efficiency, slag metal reaction, etc., it is found that electrode position control in the voltage change range between 0 and 0 is more effective than controlling the electrode position between It was found that electrode position control is better.

なお、■−〇間では溶鋼面5aが殆んど変化せず、アー
ク長に応じた電圧が発生する。
Note that between ■ and ○, the molten steel surface 5a hardly changes, and a voltage corresponding to the arc length is generated.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

従って、大電流アークを用いた直流アーク炉においては
、以上のような特性パターンをqするにも拘らず、従来
の交流アーク炉のようにスラブ厚みとアーク長とから電
圧および電流を設定し、これらの設定値に基づいてアー
ク電圧一定制御を行うものでは、上述したように■−■
間でのアークジェットによる溶鋼5のへこみ部分では可
動電極位置を変化させても電圧変化がないので全く制御
不能状態となり、最適な状態で溶鋼5の昇温を高効率に
制御できない問題がある。また、■の状態ではアークか
らの放射熱が炉壁などに向うため、溶鋼の昇温度効率が
■の状態に比べて低いという問題がある。
Therefore, in a DC arc furnace using a large current arc, despite having the above characteristic pattern, the voltage and current are set based on the slab thickness and arc length like in the conventional AC arc furnace. As mentioned above, in a device that performs constant arc voltage control based on these set values,
In the concave portion of the molten steel 5 due to the arc jet between the two, there is no voltage change even if the movable electrode position is changed, resulting in a completely uncontrollable state, and there is a problem that the temperature rise of the molten steel 5 cannot be controlled with high efficiency in an optimal state. In addition, in the state (2), the radiant heat from the arc is directed toward the furnace wall, so there is a problem that the efficiency of raising the temperature of the molten steel is lower than in the state (2).

本発明は以上のような不具合を改答するためになされた
もので、直流アーク炉の溶鋼界lR1精錬ユ程において
溶鋼の昇温効率の向上を図って精錬電力の低減化および
精錬時間の短縮化を図り、炉壁への熱損失の低減を図る
と共に溶鋼およびスラグの撹拌向上により所要とする温
度および成分の溶鋼を?lする直流アーク炉の操業方法
を提供するこ本発明による直流アーク炉の操業方法はI
−記目的を達成するために、可動電極が溶鋼面に接する
点を基準点として、予め可動電極の位置と51動電極の
電位との関係を求め、前記可動電極の1−昇に対して可
動電極の電位が急激にL昇した後一時的に変化か微少に
なる点をA点とし、その後iI動電極の1−昇に伴って
+Iiび前記可動電極の電位が」−昇し始める点をB点
とするとき、スクラップの溶解過程では可動電極電位が
前記B点に対応する可動電極電位量l−の設定電位にな
るように可動電極位置を制御し、−ノJ゛、溶鋼の昇l
H1精錬過程等においては、可動電極位置が前記A点と
B点の中間の設定位置になるように前記可動電極位置を
制御することにより、溶鋼のFi′I温効率を高め、か
つ、スラグ金属反応を最適な状態に制御するものである
The present invention has been made to solve the above-mentioned problems, and aims to improve the temperature raising efficiency of molten steel in the molten steel industry IR1 refining process of a DC arc furnace, thereby reducing the refining power and shortening the refining time. In addition to reducing heat loss to the furnace walls, the molten steel can be produced at the required temperature and composition by improving the agitation of the molten steel and slag. To provide a method for operating a DC arc furnace according to the present invention, the method for operating a DC arc furnace according to the present invention is
- In order to achieve the above purpose, the relationship between the position of the movable electrode and the potential of the movable electrode is determined in advance using the point where the movable electrode contacts the molten steel surface as a reference point, and the movable electrode is moved relative to the 1-rise of the movable electrode. Point A is the point where the potential of the electrode suddenly increases by L and then changes temporarily or slightly, and then the point where the potential of the movable electrode starts to increase by 1- as the movable electrode increases by 1- is taken as point A. When point B is set, the position of the movable electrode is controlled so that the potential of the movable electrode becomes the set potential of the movable electrode potential amount l- corresponding to the point B during the scrap melting process.
In the H1 refining process, etc., by controlling the movable electrode position so that it is set at a position intermediate between the points A and B, the Fi'I temperature efficiency of the molten steel is increased, and the slag metal It controls the reaction to the optimum condition.

〔実施例〕〔Example〕

以上、本発明の一実施例について図面を参照して説明す
る。第1図は本発明方法を適用した直流アーク炉の電極
昇降制御システムの全体(1M成を示す図であって、特
に直流アーク炉については第4図と同一部分には同一符
号を付してその詳しい説明は省略する。先ず、直流アー
ク炉への電圧印加手段は、交流電圧を所定の電圧に変成
する炉用変圧器]1、この炉用変圧器]1によって変成
された交流電圧を直流電圧に変換するサイリスタ交直変
換器12とを角し、このサイリスタ交直変換器12によ
って変換された直流電圧の負極側は平滑リアクトル13
を介して可動電極3に接続され、一方、IL極側は炉底
電極4に接続されている。そして、この可動電極3と炉
底電極4との間に所定のアーク電流(例えば40KA)
を流すように電圧を印加し、常に所望とする可動電極3
を位置制御する構成となっている。
An embodiment of the present invention will be described above with reference to the drawings. FIG. 1 is a diagram showing the entire electrode lifting control system (1M configuration) of a DC arc furnace to which the method of the present invention is applied; in particular, for the DC arc furnace, the same parts as in FIG. 4 are given the same reference numerals. A detailed explanation thereof will be omitted.Firstly, the means for applying voltage to the DC arc furnace includes a furnace transformer [1] which converts an AC voltage into a predetermined voltage; The negative pole side of the DC voltage converted by the thyristor AC/DC converter 12 is connected to a smoothing reactor 13.
is connected to the movable electrode 3 via the IL electrode, while the IL pole side is connected to the hearth bottom electrode 4. A predetermined arc current (for example, 40 KA) is applied between the movable electrode 3 and the hearth bottom electrode 4.
A voltage is applied so that the movable electrode 3 is always set as desired.
It is configured to control the position of the

この可動電極3の位置制御、とりわけスクラップ2の溶
解時における電極位置制御手段は、両市・極3,4間の
電圧を検出する発生電圧検出2;21と、pめ所定の電
圧を設定する電圧設定器22と、この電圧設定器22の
設定電圧と発生電圧検出器21からの発生電圧との偏差
を演算する減算器23と、スクラップ2の溶解時、つま
り切裂から溶は落ち工程のときに図示実線の如く閉成さ
れ、溶鋼昇温、精錬工程時に図示点線位置に閉成される
スイッチ24と、このスイッチ24を経由して前記減算
イ423から人力される電圧偏差を零とする様に比例・
積分演算を行って速度設定値(絶対値)を得る速度設定
制御器25等で(を成され、さらに上R・下降切換回路
26、速度別ga器27、この速度制御器27の出力で
駆動制御される電極昇降制御用電動[28等が備えられ
ている。
The means for controlling the position of the movable electrode 3, especially when melting the scrap 2, includes a generated voltage detector 2; 21 that detects the voltage between the two electrodes 3 and 4, and a voltage that sets a predetermined voltage. A setting device 22, a subtractor 23 that calculates the deviation between the set voltage of the voltage setting device 22 and the generated voltage from the generated voltage detector 21, and a subtracter 23 that calculates the deviation between the set voltage of the voltage setting device 22 and the generated voltage from the generated voltage detector 21, and when melting the scrap 2, that is, during the process of melting from the cut. A switch 24 is closed as shown by the solid line in the figure, and is closed to the dotted line position in the figure during the molten steel temperature raising and refining process, and the voltage deviation manually applied from the subtraction 423 via this switch 24 is set to zero. proportional to
This is done by a speed setting controller 25 etc. which performs an integral calculation to obtain a speed setting value (absolute value), and is further driven by an upper R/lower switching circuit 26, a speed-specific GA device 27, and the output of this speed controller 27. An electric motor [28, etc.] for controlling electrode elevation is provided.

前記十−昇・下降切換回路26は、速度設定制御器25
からの速度設定値が人力され、前記電圧偏差の正負極性
に応して速度設定値に正または負の極性を付加して工賃
または下降移動速度指令値を出力する機能をちっている
The above-mentioned ascending/descending switching circuit 26 is connected to a speed setting controller 25.
The speed setting value is input manually, and a positive or negative polarity is added to the speed setting value according to the positive or negative polarity of the voltage deviation to output a labor charge or a downward movement speed command value.

この電動機28は速度制御器27の出力に応じて正転ま
たは逆転しながらウィンチ31を回転させて一端を固定
端とするワイヤ32の他端を巻取りまたは昼戻すことに
より、滑+3′Bを介してマス1−34を−Lド動させ
水゛トアーム34を介してロ■動71i極3を昇降制御
する構成となっている。
This electric motor 28 rotates the winch 31 while rotating forward or reverse depending on the output of the speed controller 27, and winds up or returns the other end of the wire 32, which has one end as a fixed end, thereby increasing the slip +3'B. The configuration is such that the mass 1-34 is moved by the -L direction through the water arm 34, and the vertical movement 71i of the pole 3 is controlled up and down.

次に、溶鋼昇温、精錬工程ての可動電極3の電極位置制
御手段は、i1動電極位置を検出する電極位置センサ4
1と、このa NM位14センサ41から送られてくる
可動電極3の溶鋼接触位置検出値を取込んで記憶する溶
鋼接触位置検知回路42と、T・めアーク電流に括づい
て可動電極位置と可動電極3の電位との関係が求められ
、前記溶鋼接触位置検知値に基づいて最適電極上昇位置
を決定する電極上昇位置演算−ト段43と、この演算手
段43でiすられた最適電極1−昇位置と電極位置セン
サ21からの現在電極位置との偏差を求める減算器44
 ’:、’;で構成され、この減算器44で得られた偏
差信号がスイッチ24を介して前記速度設定制御器26
へ供給する(を成となっている。
Next, the electrode position control means of the movable electrode 3 in the molten steel temperature raising and refining process is an electrode position sensor 4 that detects the i1 movable electrode position.
1, a molten steel contact position detection circuit 42 that captures and stores the detected value of the molten steel contact position of the movable electrode 3 sent from the sensor 41, and the potential of the movable electrode 3, and an electrode lifting position calculation stage 43 for determining the optimum electrode lifting position based on the detected value of the molten steel contact position; 1- Subtractor 44 for determining the deviation between the ascending position and the current electrode position from the electrode position sensor 21
':, ';, and the deviation signal obtained by this subtracter 44 is sent to the speed setting controller 26 via the switch 24.
supply to (becomes).

次に、以上のように構成された電極9r降制御システム
の動作について説明する。アーク炉1にスクラップを装
入し炉蓋6を閉止した後、炉蓋6を通して11動屯極3
を挿入し、このnJ動組電極3炉底電極4間に所定の電
圧を印加して「11動電極先端からアークを発生させな
がらスクラップを順次溶解していく。このスクラップの
溶解は、直流アーク炉の操着工程中、特にスクラップ装
入直後の点弧工程、ポーリング工程、安定期工程、棚落
ち工程、スクラップを+IG度装入する追装工程等で行
われる。
Next, the operation of the electrode 9r lowering control system configured as above will be explained. After charging scrap into the arc furnace 1 and closing the furnace lid 6, the 11-pulse pole 3 is passed through the furnace lid 6
A predetermined voltage is applied between the nJ moving electrode 3 and the bottom electrode 4, and the scrap is sequentially melted while generating an arc from the tip of the moving electrode. This is carried out during the operation process of the furnace, especially in the ignition process immediately after charging scrap, the polling process, the stabilization process, the shelving process, and the additional loading process in which scrap is charged at +IG degree.

しかして、このスクラップの溶解時には自動または手動
にてスイッチ24を図示実線側に閉成し、かつ、第2図
に示す特性パターン(第5図と同様なパターン)のうち
B−D間の特性を前提とじつつ可動電極3をシフ降制御
する。
Therefore, when melting this scrap, the switch 24 is automatically or manually closed to the solid line side shown in the diagram, and the characteristic between B and D of the characteristic pattern shown in FIG. 2 (same pattern as in FIG. 5) is Shift-down control of the movable electrode 3 is performed based on the premise that:

具体的には、可動電極3のアーク長によって変化する画
電極3,4間の発生電圧を発生電圧検出器21て検出し
た後、この発生電圧と電圧設定器22の設定電圧との偏
差信号をスイッチ24を通して速度設定制御器25に供
給すると、この速度設定ルリ御2;25ではその偏差信
号が零となる劃、lに比例・積分演算を行って速度設定
値を得、これを上昇・ド降切換回路26に供給する。こ
こで、上昇・下降切換回路26は減算423から送られ
て来る偏差ft号の極性を付加して速度設定値を移動速
度指令値として出力する。この移動速度指令値を受けて
速度制O1I器27は電極昇降制御用電動機28を所要
とする方向へ回転駆動すると、この電動機28の回転ノ
j向にしたがって可動電極3は所要とするツノ°向へ昇
降制御される。このスクラップ溶解時は可動電極3を溶
鋼面から所定距離2つまり第2図のB−D間で行うので
、アーク長に応じて電圧が変化するので、この電圧を一
定に制御するように可動電極3を昇降制御することにな
る。
Specifically, after the generated voltage between the picture electrodes 3 and 4, which changes depending on the arc length of the movable electrode 3, is detected by the generated voltage detector 21, a deviation signal between this generated voltage and the set voltage of the voltage setting device 22 is detected. When the signal is supplied to the speed setting controller 25 through the switch 24, when the deviation signal becomes zero, the speed setting controller 25 performs proportional/integral calculations on l to obtain the speed setting value, which is then used to raise or lower the speed. It is supplied to the down switching circuit 26. Here, the ascending/descending switching circuit 26 adds the polarity of the deviation ft sent from the subtractor 423 and outputs the speed setting value as a moving speed command value. In response to this movement speed command value, the speed limiter 27 rotates the electric motor 28 for electrode elevation control in the required direction, and the movable electrode 3 moves in the required horn direction according to the rotational direction of the electric motor 28. It is controlled to raise and lower. During this scrap melting, the movable electrode 3 is placed at a predetermined distance 2 from the molten steel surface, that is, between B and D in Figure 2, so the voltage changes depending on the arc length, so the movable electrode 3 is 3 will be controlled to raise and lower.

次に、溶fF4 W IM 、精錬工程においては、自
動または手動にてスイッチ24を図示点線側に閉成して
口■動電極3の警隊制御を行う。この制御においては電
極位置センサ41から送られてくる可動電極3の溶鋼接
触位置検出値loを溶鋼接触位置検知回路42で取込ん
で記憶した後、その溶鋼接触位置検出値I!oを電極り
好位置演算手段43に供給する。この電極1−好位置演
算手段43では−r−め所望とするアーク電流f (1
)に基づき第2図のような特性パターン、つまり可動電
極3の位置と可動電極3の電位の関係から最適電極上昇
値△lが定められているので、溶鋼接触位置検知回路4
2から溶鋼接触位置検出値ノ。を受けるとその検出値1
0に最適電極上昇値Δノを加算した値を最適電極設定位
置11として出力し減算器44に供給する。この減算器
44ては電極設定位置ノ。
Next, in the melting fF4W IM and refining process, the switch 24 is automatically or manually closed to the dotted line side in the figure to control the oral motion electrode 3. In this control, the molten steel contact position detection value lo of the movable electrode 3 sent from the electrode position sensor 41 is captured and stored in the molten steel contact position detection circuit 42, and then the molten steel contact position detection value I! o is supplied to the electrode good position calculation means 43. This electrode 1-optimal position calculating means 43 calculates the desired arc current f (1
), the optimum electrode rise value △l is determined from the characteristic pattern shown in FIG.
2 to molten steel contact position detection value. When received, the detected value 1
The value obtained by adding the optimum electrode rise value Δ to 0 is output as the optimum electrode setting position 11 and supplied to the subtracter 44. This subtracter 44 corresponds to the electrode setting position.

と電極位置センサ41からの可動電極3の現在位置との
偏差(X号を求め、前記速度設定制御器25に供給する
。従って、この速度設定器25の出力に基づいて速度制
御器27から操作出力を電動機28に供給し、口f動電
極3を第2図に示す電極設定位置I!1.つまりA−8
間の特にA点近傍に設定する。この電極位置は第3図に
示すように可動電極3からのジェットアークがスラグ8
を通って溶鋼2にへこみを作る位置関係にあり、このア
ークの側部からスラグ8によ(熱が通り、スラグメタル
の反応を良好なものとする。
The deviation (No. The output is supplied to the electric motor 28, and the mouth electrode 3 is moved to the electrode setting position I!1, that is, A-8, as shown in FIG.
In particular, the setting should be made near point A. This electrode position is such that the jet arc from the movable electrode 3 reaches the slug 8 as shown in Figure 3.
The arc is located in a positional relationship that creates a depression in the molten steel 2 through the arc, and heat passes through the side of the arc to the slag 8, improving the reaction of the slag metal.

従って、以上のような実施例の構成によれば、溶鋼R温
、精錬1ユ程時に可動゛電極3の溶鋼接触位置およびア
ーク電流によって定まる電極上夕?位置とに基づいてi
iJ動電極電極望とする位置に1冒制御するので、確実
に溶鋼の’iI′温効率を高めることができ、これによ
って精錬工程での電力原単位を向上でき、また精錬時間
を短縮できる。また、スラグフナーミングのための酸素
、炭粉最の低減化を図ることかでき、さらに第3図に示
すように可動電極3のアークジェットによって適切に撹
拌作用を行うことが61能となり、よって溶鋼の温度お
よび成分を均一化することができ、均−製品の溶鋼を得
ることができる。
Therefore, according to the configuration of the embodiment as described above, the electrode temperature is determined by the molten steel R temperature, the molten steel contact position of the movable electrode 3, and the arc current during about 1 unit of refining. i based on the position and
Since the iJ moving electrode is controlled to the desired position, the 'iI' temperature efficiency of the molten steel can be reliably increased, thereby improving the electric power consumption in the refining process and shortening the refining time. In addition, it is possible to reduce the amount of oxygen and coal powder required for slag nourishing, and furthermore, as shown in Fig. 3, it is possible to perform an appropriate stirring action by the arc jet of the movable electrode 3. The temperature and composition of molten steel can be made uniform, and a uniform product of molten steel can be obtained.

〔発明の効果〕〔Effect of the invention〕

以上詳記したように本発明によれば、溶鋼昇温。 As detailed above, according to the present invention, the temperature of molten steel can be increased.

精錬時に電圧一定制御を排除して可動電極の位置を所望
とする最適位置に設定することにより、溶鋼の昇温効率
を大幅に向上でき、精錬電力の低減化および精錬時間の
短縮化が図れ、溶鋼およびスラグの撹拌向上により所要
とする温度および成分の溶鋼をjすることかできる。
By eliminating constant voltage control during refining and setting the position of the movable electrode to the desired optimal position, the efficiency of heating up molten steel can be greatly improved, reducing refining power and reducing refining time. By improving the stirring of molten steel and slag, it is possible to obtain molten steel at the required temperature and composition.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図ないし第3図は本発明に係わる直流アーク炉の操
業方法の一実施例を説明するために示したもので、第1
図は本発明Ji法を適用した電極昇降制御システムの構
成図、第2図は溶鋼昇温、精錬時の最適電極設定位置を
説明する図、第3図は可動1u極のアークと溶鋼および
スラグとの位置関係を示す図、第4図ないし第6図は従
来方法を説明するための図であって、第4図は直流アー
ク炉の一般的な操業上程を説明する図、第5図はあるア
ーク電流のときの電極位置と発生電圧との特性パターン
図、第6図は第5図の各電極位置と溶鋼位置およびスラ
グ位置との関係図である。 1・・・アーク炉、3・・・可動電極、4・・炉底電極
、5・・・溶鋼、8・・スラグ、21・・・発生電圧検
出器、22・・電圧設定器、24・・・スイッチ、25
・・・速度設疋制御器、26・・・上昇・下降切換回路
、27・・・速度制御器、28・・・電極昇降制御用電
動機、41・・電極位置センサ、42・・・溶鋼接触位
置検知回路、4′3・・・電極1.好位置演算手段、4
4・・・減算器。
Figures 1 to 3 are shown to explain one embodiment of the method of operating a DC arc furnace according to the present invention.
The figure is a configuration diagram of an electrode lifting control system applying the Ji method of the present invention, Figure 2 is a diagram explaining the optimal electrode setting position during temperature rise and refining of molten steel, and Figure 3 is a diagram showing the arc of the movable 1U pole, molten steel, and slag. Figures 4 to 6 are diagrams for explaining the conventional method, Figure 4 is a diagram for explaining the general operation process of a DC arc furnace, and Figure 5 is a diagram for explaining the general operation process of a DC arc furnace. FIG. 6 is a characteristic pattern diagram of the electrode position and generated voltage at a certain arc current. FIG. 6 is a diagram of the relationship between each electrode position in FIG. 5 and the molten steel position and slag position. DESCRIPTION OF SYMBOLS 1... Arc furnace, 3... Movable electrode, 4... Furnace bottom electrode, 5... Molten steel, 8... Slag, 21... Generated voltage detector, 22... Voltage setting device, 24... ...Switch, 25
...Speed setting controller, 26...Ascending/descending switching circuit, 27...Speed controller, 28...Electrode elevation control motor, 41...Electrode position sensor, 42... Molten steel contact Position detection circuit, 4'3...electrode 1. Good position calculation means, 4
4...Subtractor.

Claims (1)

【特許請求の範囲】 可動電極を昇降制御しながら固体金属を溶解する直流ア
ーク炉において、 前記可動電極が溶融金属面に接する点を基準点として、
予め可動電極の位置と可動電極の電位との関係を求め、
前記可動電極の上昇に対して可動電極の電位が急激に上
昇した後一時的に変化が微少になる点をA点とし、その
後可動電極の上昇に伴って再び前記可動電極の電位が上
昇し始める点をB点とするとき、 前記固体金属の溶解過程では可動電極電位が前記B点に
対応する可動電極電位以上の設定電位になるように可動
電極位置を操作し、 前記溶融金属の昇温、精錬過程では、可動電極位置が前
記A点とB点の中間の設定位置になるように前記可動電
極位置を制御することを特徴とする直流アーク炉の操業
方法。
[Claims] In a DC arc furnace that melts solid metal while controlling a movable electrode to move up and down, the point where the movable electrode touches the molten metal surface is set as a reference point,
Find the relationship between the position of the movable electrode and the potential of the movable electrode in advance,
Point A is the point where the potential of the movable electrode suddenly increases with respect to the rise of the movable electrode, and then temporarily changes slightly, and then the potential of the movable electrode starts to rise again as the movable electrode rises. When the point is defined as point B, in the melting process of the solid metal, the movable electrode position is operated so that the movable electrode potential becomes a set potential higher than the movable electrode potential corresponding to the B point, and the temperature of the molten metal is increased. A method for operating a DC arc furnace, characterized in that, in the refining process, the movable electrode position is controlled so that the movable electrode position is set at a position intermediate between the A point and the B point.
JP63205802A 1988-08-19 1988-08-19 Operation method of DC arc furnace Expired - Lifetime JP2641913B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63205802A JP2641913B2 (en) 1988-08-19 1988-08-19 Operation method of DC arc furnace

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63205802A JP2641913B2 (en) 1988-08-19 1988-08-19 Operation method of DC arc furnace

Publications (2)

Publication Number Publication Date
JPH0254889A true JPH0254889A (en) 1990-02-23
JP2641913B2 JP2641913B2 (en) 1997-08-20

Family

ID=16512925

Family Applications (1)

Application Number Title Priority Date Filing Date
JP63205802A Expired - Lifetime JP2641913B2 (en) 1988-08-19 1988-08-19 Operation method of DC arc furnace

Country Status (1)

Country Link
JP (1) JP2641913B2 (en)

Also Published As

Publication number Publication date
JP2641913B2 (en) 1997-08-20

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