JPH01170558A - Control method for direct electrified heating of pouring nozzle - Google Patents
Control method for direct electrified heating of pouring nozzleInfo
- Publication number
- JPH01170558A JPH01170558A JP32861987A JP32861987A JPH01170558A JP H01170558 A JPH01170558 A JP H01170558A JP 32861987 A JP32861987 A JP 32861987A JP 32861987 A JP32861987 A JP 32861987A JP H01170558 A JPH01170558 A JP H01170558A
- Authority
- JP
- Japan
- Prior art keywords
- nozzle
- amt
- temp
- heat radiation
- electric power
- 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.)
- Pending
Links
- 238000010438 heat treatment Methods 0.000 title claims abstract description 13
- 238000000034 method Methods 0.000 title claims description 8
- 238000002347 injection Methods 0.000 claims description 12
- 239000007924 injection Substances 0.000 claims description 12
- 230000005611 electricity Effects 0.000 claims description 5
- 239000002184 metal Substances 0.000 abstract description 13
- 230000005855 radiation Effects 0.000 abstract description 7
- 238000007598 dipping method Methods 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 12
- 239000010959 steel Substances 0.000 description 12
- 238000005266 casting Methods 0.000 description 7
- 238000007654 immersion Methods 0.000 description 7
- 239000010953 base metal Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical compound [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
- B22D41/60—Pouring-nozzles with heating or cooling means
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、溶融金属を流通させる注入ノズルの内壁に地
金が凝固・付着することを防止するために、注入ノズル
を通電加熱する際の加熱条件を制御する方法に関する。[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for preventing base metal from solidifying and adhering to the inner wall of the injection nozzle through which molten metal flows, when heating the injection nozzle with electricity. The present invention relates to a method of controlling heating conditions.
連続鋳造において、取鍋からタンデイツシュ、或いはタ
ンデイツシュからモールドに溶融金属を供給する際、外
気と接触することに起因して溶融金属が酸化することを
防止するため、浸漬ノズルやロングノズル等の注入ノズ
ルを使用して、外気と遮断された状態で溶融金属を注入
している。In continuous casting, when supplying molten metal from the ladle to the tundish or from the tundish to the mold, injection nozzles such as immersion nozzles and long nozzles are used to prevent molten metal from oxidizing due to contact with outside air. is used to inject molten metal while isolated from the outside air.
この注入ノズルは、鋳込み開始時に高温の溶鋼がノズル
内を流下する際に、熱ｉ撃を受ける。また、溶鋼による
摩耗や溶損、溶鋼成分やパウダー成分との反応等にも曝
される。このような使用条件から、耐熱衝撃性、耐食性
、耐溶損性、耐摩耗性等に優れた材料でノズルを製造す
ることが要求される。この点で、アルミナ、炭素等の中
性材料がもっている化学的安定性、及び炭素（黒鉛）の
低弾性、低膨張率を利用したアルミナ−カーボン質の耐
火物が注入ノズルの材料として用いられている。This injection nozzle receives a thermal shock when hot molten steel flows down inside the nozzle at the start of casting. It is also exposed to abrasion and erosion caused by molten steel, and reactions with molten steel components and powder components. Such usage conditions require that nozzles be manufactured from materials with excellent thermal shock resistance, corrosion resistance, erosion resistance, abrasion resistance, and the like. In this respect, alumina-carbon refractories are used as injection nozzle materials, taking advantage of the chemical stability of neutral materials such as alumina and carbon, and the low elasticity and low expansion coefficient of carbon (graphite). ing.
ところで、鋳造中の溶鋼温度は、鋳込み初期及び鋳込み
末期に低下し易い。この温度低下に伴って、ノズルの内
壁に地金が付着し、溶鋼の流動状態が不安定になり、一
定した品質の鋳片を得ることが困難になる。地金の付着
は、ついにはノズル内を閉塞する場合もある。この傾向
は、鋳片品質の面から低温鋳造を必要とする鋼種を鋳込
む場合に顕著に現れる。By the way, the temperature of molten steel during casting tends to decrease at the beginning of casting and at the end of casting. As the temperature decreases, the base metal adheres to the inner wall of the nozzle, making the flow state of the molten steel unstable and making it difficult to obtain slabs of consistent quality. The adhesion of metal may eventually clog the inside of the nozzle. This tendency becomes noticeable when casting steel types that require low-temperature casting in terms of billet quality.
この地金付着を防止するため、ノズル外表面に断熱材を
施す等の対策がとられているが、充分な効果が得られて
いない。そこで、注入ノズル自体を直接的に通電加熱す
ることにより、溶融金属の温度低下を防止し、地金の析
出、付着によるノズルの閉塞を防止することが特開昭５
５−６４８５７号公報で提案されている。In order to prevent this metal adhesion, measures such as applying a heat insulating material to the outer surface of the nozzle have been taken, but sufficient effects have not been obtained. Therefore, by directly heating the injection nozzle itself with electricity, it is possible to prevent the temperature of the molten metal from decreasing and to prevent the nozzle from clogging due to precipitation and adhesion of base metal.
This is proposed in Japanese Patent No. 5-64857.
このように注入ノズルを通電加熱するとき、ノズル耐火
物の表面温度を熱電対で検出し、この表面温度が一定と
なるように通電加熱用の入力電力を制御している。これ
は、ノズルの内面温度が直接測定できないためであり、
ノズル耐火物の表面温度から非定常熱伝導計算によって
ノズルの内面温度を推定している。When the injection nozzle is electrically heated in this way, the surface temperature of the nozzle refractory is detected by a thermocouple, and the input power for electrical heating is controlled so that this surface temperature remains constant. This is because the internal temperature of the nozzle cannot be measured directly.
The inner surface temperature of the nozzle is estimated from the surface temperature of the nozzle refractory by unsteady heat conduction calculation.
ところが、このように表面温度からノズルの内部温度を
推定する方法は、計算負荷が大きく、かつ、推定誤差も
伴う。したがって、入力電力に過剰又は不足が生じる。However, this method of estimating the internal temperature of the nozzle from the surface temperature requires a large calculation load and is accompanied by estimation errors. Therefore, an excess or shortage of input power occurs.
そして、入力電力が不足する場合、地金の析出に起因し
たノズル内の閉塞が生じる。逆に過剰の場合には、ノズ
ルが過剰に加熱され、酸化劣化等によるノズルの損傷が
著しくなる。また、過剰な電力を投入すること自体、省
エネルギーの面で不利なものである。If input power is insufficient, blockage in the nozzle occurs due to metal deposition. On the other hand, if the amount is excessive, the nozzle will be heated excessively and damage to the nozzle due to oxidative deterioration etc. will become significant. In addition, inputting excessive power is itself disadvantageous in terms of energy conservation.
そこで、本発明は、ノズル外表面における放熱量に基づ
き投入電力量を制御することによって、ノズルの内面温
度を精度良く必要なレベルに維持し、安定した条件下で
の溶融金属の注入を行うことを目的とする。Therefore, the present invention maintains the internal temperature of the nozzle at a required level with high accuracy by controlling the amount of power input based on the amount of heat dissipated on the outer surface of the nozzle, and injects molten metal under stable conditions. With the goal.
本発明の通電加熱制御方法は、その目的を達成するため
に、通電加熱される注入ノズルの表面温度を計測し、こ
の測定値を演算器に入力してノズル表面からの放熱量を
演算し、該放熱量にバランスする電力を前記注入ノズル
に供給することを特徴とする。In order to achieve its purpose, the current heating control method of the present invention measures the surface temperature of an injection nozzle that is heated by current, inputs this measured value into a calculator, and calculates the amount of heat dissipated from the nozzle surface. The method is characterized in that the injection nozzle is supplied with electric power that balances the amount of heat dissipated.
以下、図面を参照しながら、実施例により本発明の特徴
を具体的に説明する。Hereinafter, the features of the present invention will be specifically explained using examples with reference to the drawings.
第１図は、本実施例で使用した通電加熱の制御系を示す
。FIG. 1 shows a control system for electrical heating used in this example.
タンディッシ５１の底部に取り付けられた浸漬ノズル２
に、圧着又はボルト締め等の手段によって給電電極３が
固定されている。この給電電極３には、電源４からの電
流を人力制御器５によって制御した後の電流を入力して
いる。また、浸漬ノズル２の表面に熱電対６が取り付け
られており、この熱電対６により検出された浸漬ノズル
２の表面温度が演算器７に入力される。演算器７では、
この人力された表面温度から浸漬ノズル２表面からの放
熱量を演算し、その演算結果を入力制御器５に出力する
。このようにして、浸漬ノズル２表面の放熱量と平衡に
なるような電力が、入力制御器５から給電電極３に供給
される。Immersion nozzle 2 attached to the bottom of Tandissi 51
The power supply electrode 3 is fixed by means such as crimping or bolting. A current from a power source 4 is input to the power supply electrode 3 after being controlled by a human controller 5 . Further, a thermocouple 6 is attached to the surface of the immersed nozzle 2, and the surface temperature of the immersed nozzle 2 detected by the thermocouple 6 is inputted to the calculator 7. In the computing unit 7,
The amount of heat radiation from the surface of the immersion nozzle 2 is calculated from this manually determined surface temperature, and the calculation result is output to the input controller 5. In this way, the input controller 5 supplies power to the power supply electrode 3 in a manner that is in balance with the amount of heat dissipated from the surface of the submerged nozzle 2 .
第２図は、この加熱制御方式による作用を具体的に説明
する図である。ただし、同図（ａ）は浸漬ノズルを通電
加熱した場合を示し、同図（ｂ）は通電加熱なしの場合
を示す。FIG. 2 is a diagram specifically explaining the effect of this heating control method. However, the same figure (a) shows the case where the immersion nozzle is heated with electricity, and the same figure (b) shows the case where there is no electricity heated.
人力電力Ｑ６ が０の場合、ノズルからの放熱量Ｑ’ｏ
ｕ ｔ は、第２図ら〕に示すように全て溶鋼から供
給され、溶鋼の温度が低下する。したがって、このとき
のノズル外表面温度Ｔ０から、放射、対流による熱伝達
量として放熱量Ｑ。ｕｔが求められる。When the human power Q6 is 0, the amount of heat released from the nozzle Q'o
As shown in Fig. 2, etc., all of u t is supplied from the molten steel, and the temperature of the molten steel is lowered. Therefore, from the nozzle outer surface temperature T0 at this time, the heat radiation amount Q is the amount of heat transferred by radiation and convection. ut is required.
この放熱量Ｑ。ｕｔは、溶鋼の放熱量Ｑ、に等しく、温
度低下した溶鋼がノズルの内壁に付着することになる。This heat radiation amount Q. ut is equal to the heat dissipation amount Q of the molten steel, and the molten steel whose temperature has decreased will adhere to the inner wall of the nozzle.
これに対し、通電加熱用の電力Ｑ、をノズルに供給する
と、ノズルの内面温度Ｔ＋ が上昇する。On the other hand, when electric power Q for electrical heating is supplied to the nozzle, the inner surface temperature T+ of the nozzle increases.
そして、放熱量Ｑ、いに等しい電力ＱＥを供給するとき
、理論的にはノズルの内面温度Ｔｔ が溶鋼温度Ｔ、に
等しくなり、溶鋼からの放熱量Ｑ、は０となる。すなわ
ち、溶鋼の温度降下が生じず、ノズル内面に地金が付着
することが防止される。When power QE equal to the amount of heat dissipated Q is supplied, theoretically the internal temperature Tt of the nozzle becomes equal to the temperature T of the molten steel, and the amount of heat dissipated from the molten steel Q becomes zero. That is, the temperature of the molten steel does not drop, and base metal is prevented from adhering to the inner surface of the nozzle.
たとえば、アルミナ７０重量％、黒鉛３０重景％の組成
をもち、内径が６０ｍｍ、 外形１３０ｍ、 長さ
６００ｍｍの浸漬ノズル２に対する通電加熱を、次のよ
うにして制御した。熱電対６で測定した浸漬ノズル２の
外表面温度は６００ ℃であり、このときの放熱量は１
８ＫＷに相当した。そこで、この放熱量に見合う電力を
ノズルに供給すると、３０分後にノズル外表面温度は１
３５０℃に達した。この状態で、２４０トンの取鍋で５
鍋連続の受湯を安定した条件下で行うことができた。ま
た、通湯後のノズル内を調査した結果、地金付着もなく
且つノズルの損傷もなかった。For example, the electrical heating of the immersion nozzle 2 having a composition of 70% by weight of alumina and 30% by weight of graphite and having an inner diameter of 60 mm, an outer diameter of 130 m, and a length of 600 mm was controlled as follows. The outer surface temperature of the immersion nozzle 2 measured with the thermocouple 6 is 600 °C, and the amount of heat dissipated at this time is 1
It was equivalent to 8KW. Therefore, when power is supplied to the nozzle in accordance with this amount of heat dissipation, the nozzle outer surface temperature decreases to 1 after 30 minutes.
The temperature reached 350°C. In this state, a 240 ton ladle will
It was possible to continuously receive hot water in a pot under stable conditions. Furthermore, as a result of inspecting the inside of the nozzle after pouring hot water, there was no metal adhesion and no damage to the nozzle.
これに対し、１５ Ｋ Ｗの人力電力を加えた場合、ノ
ズル内壁に若干の地金付着がみられた。また、２２ＫＷ
の電力を投入した場合は、地金付着がないものの、浸漬
ノズル２が過度に加熱され、ノズル内面に組織劣化が観
察された。On the other hand, when 15 KW of human power was applied, some metal adhesion was observed on the inner wall of the nozzle. Also, 22KW
When power was applied, although there was no base metal adhesion, the immersion nozzle 2 was excessively heated and structural deterioration was observed on the inner surface of the nozzle.
以上に説明したように、本発明においては、ノズルの外
表面における放熱量に見合った電力を投入することによ
り、必要最小限の入力電力でノズルを安定して加熱がで
き、ノズル内壁に対する地金の付着を防止することがで
きる。また、溶融金属の鋳込温度が低下できる等の利点
も得られる。As explained above, in the present invention, by inputting power commensurate with the amount of heat dissipated from the outer surface of the nozzle, the nozzle can be stably heated with the minimum necessary input power, and the bare metal against the inner wall of the nozzle can be heated stably. can prevent the adhesion of Further, advantages such as lowering the casting temperature of the molten metal can be obtained.
第１図は本発明の実施例で使用した制御系を示し、第２
図は本発明の作用を具体的に説明するための図である。FIG. 1 shows the control system used in the embodiment of the present invention, and the second
The figure is a diagram for specifically explaining the operation of the present invention.
Claims (1)
の測定値を演算器に入力してノズル表面からの放熱量を
演算し、該放熱量にバランスする電力を前記注入ノズル
に供給することを特徴とする注入ノズル直接通電加熱の
制御方法。1. Measuring the surface temperature of the injection nozzle that is heated by electricity, inputting this measured value into a calculator to calculate the amount of heat dissipated from the nozzle surface, and supplying power to the injection nozzle that balances the amount of heat dissipated. A method for controlling direct energization heating of an injection nozzle, characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32861987A JPH01170558A (en) | 1987-12-24 | 1987-12-24 | Control method for direct electrified heating of pouring nozzle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32861987A JPH01170558A (en) | 1987-12-24 | 1987-12-24 | Control method for direct electrified heating of pouring nozzle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01170558A true JPH01170558A (en) | 1989-07-05 |
Family
ID=18212291
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32861987A Pending JPH01170558A (en) | 1987-12-24 | 1987-12-24 | Control method for direct electrified heating of pouring nozzle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01170558A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5830376A (en) * | 1992-07-16 | 1998-11-03 | Minnesota Mining And Manufacturing Company | Topographical selective patterns |
-
1987
- 1987-12-24 JP JP32861987A patent/JPH01170558A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5830376A (en) * | 1992-07-16 | 1998-11-03 | Minnesota Mining And Manufacturing Company | Topographical selective patterns |
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