JP4501892B2 - Method and apparatus for estimating molten metal temperature in continuous casting mold - Google Patents
Method and apparatus for estimating molten metal temperature in continuous casting mold Download PDFInfo
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本発明は、液体金属の連続鋳造において鋳型内の溶湯温度を推定する技術に関する。特に、鋳型内の溶鋼に直接プローブ等を浸漬することなく、経時的に連続して測定が可能で、消耗品が極力少ないことを条件として、推定精度の良い鋳型内溶鋼温度の推定技術に関する。 The present invention relates to a technique for estimating a molten metal temperature in a mold in continuous casting of a liquid metal. In particular, the present invention relates to a technique for estimating the molten steel temperature in the mold with high estimation accuracy on the condition that the measurement can be continuously performed over time without directly immersing the probe or the like in the molten steel in the mold and there are as few consumables as possible.
溶鋼などの溶湯の連続鋳造において鋳型（モールド）内の溶湯温度を知ることは各種の鋳造条件を設定する上で重要である。例えば、鋼の連続鋳造では、鋳型内の溶鋼温度が高すぎると凝固シェルの発達が遅れブレークアウトにつながり、又、等軸晶の生成が阻害されて中心偏析の悪化を引き起こす。逆に鋳型内の溶鋼温度が低すぎると、鋳型内湯面の皮張りやモールドパウダーの溶融不良で、品質障害やブレークアウトの原因となる。 Knowing the temperature of the molten metal in the mold (mold) in continuous casting of molten metal such as molten steel is important in setting various casting conditions. For example, in the continuous casting of steel, if the molten steel temperature in the mold is too high, the solidification shell development is delayed, leading to a breakout, and the formation of equiaxed crystals is hindered, leading to deterioration of central segregation. On the other hand, if the molten steel temperature in the mold is too low, the surface of the molten metal in the mold or the poor melting of the mold powder will cause quality failure or breakout.
従来、広く行われている方法として（１）タンディッシュ内の溶鋼温度を測定して、タンディッシュ〜鋳型間の温度効果量を予測して鋳型内の溶鋼温度を推定する方法がある。タンディッシュ内の溶綱温度を測定する手段としては、消耗型の熱電対でスポット測定を行うことが一般的である。更に一部では、耐火物の保護管に覆われた持久式熱電対により連続測定を行ったり、樹脂被覆の光ファイバーを浸漬して放射温度を測定することも行われている。 Conventionally, as a widely used method, there is (1) a method of estimating a molten steel temperature in a mold by measuring a molten steel temperature in the tundish and predicting a temperature effect amount between the tundish and the mold. As a means for measuring the temperature of the molten steel in the tundish, spot measurement is generally performed with a consumable thermocouple. Further, in some cases, continuous measurement is performed with a permanent thermocouple covered with a refractory protective tube, or radiation temperature is measured by immersing a resin-coated optical fiber.
又、（２）鋳型内の溶鋼温度を直接測定する方法も提案されており、例えば、特許文献１では、測温紙管に２〜３ｍｍピッチで埋め込んだ測温プローブを昇降装置によって鋳型内溶鋼に約１分間浸漬し、鋳込みの初期、中期、末期にかけて数回測定する方法が開示されている。又、特許文献２ではサーメット製の保護管に覆われた熱電対を鋳型内溶鋼中に連続的に浸漬している。
In addition, (2) a method for directly measuring the molten steel temperature in the mold has been proposed. For example, in Patent Document 1, a temperature measuring probe embedded in a temperature measuring paper tube at a pitch of 2 to 3 mm is lifted by a lifting device. In this method, the sample is immersed for about 1 minute and measured several times during the initial, middle and final stages of casting. In
又、（３）鋳型内の溶鋼温度を間接的に測定する方法として、特許文献３で、鋳型銅板外面の溶鋼メニスカス部位近傍の温度分布を非接触で冷却箱背面から測定可能とする耐熱窓ガラスを冷却箱に設け、この窓ガラスを通じて放射温度計で溶鋼の温度を計測している。 (3) As a method for indirectly measuring the molten steel temperature in the mold, Patent Document 3 discloses a heat-resistant window glass that can measure the temperature distribution in the vicinity of the molten steel meniscus portion on the outer surface of the mold copper plate from the back of the cooling box without contact. Is provided in the cooling box, and the temperature of the molten steel is measured with a radiation thermometer through this window glass.
しかしながら、（１）のタンディッシュ内の溶鋼温度を計測して鋳型内の溶鋼温度を推定する方法では、タンディッシュ〜鋳型間の溶鋼温度降下量にバラツキがあるような環境、例えば、タンディッシュの耐火物ライニング厚みが溶損で大きく変わる場合、又、タンディッシュのホットリサイクルを行う場合、リサイクルタイムがばらついてタンディッシュの含熱量がばらつく場合等の環境では、推定した鋳型内溶鋼温度に大きなバラツキが生じる。 However, in the method (1) of measuring the molten steel temperature in the tundish and estimating the molten steel temperature in the mold, an environment where there is a variation in the molten steel temperature drop between the tundish and the mold, for example, in the tundish When the thickness of the refractory lining changes significantly due to melting damage, when hot recycling of tundish is performed, or when the heat content of tundish varies due to variations in recycling time, the estimated molten steel temperature in the mold varies greatly. Occurs.
又、（２）の鋳型内の溶鋼に直接プローブを浸漬する方法では、消耗方熱電対では溶鋼温度の経時連続的な情報を得ることは困難である。又、サーメットなどの保護管を連続浸漬する方法でも、鋳型内のように溶鋼流速が速い（０．１〜０．５ｍ／ｓ程度）環境では保護管の寿命が限られ（１時間〜数時間程度）、常時測定するには保護管のコストと交換作業が必要である。又、これらの鋳型内溶鋼に直接プローブを浸漬する方法では、浸漬時にモールドパウダーを溶鋼中に巻き込んだり、プローブの周りに付着した地金が溶鋼中に脱落したり、浸漬したプローブの周りに溶鋼流れの渦が生じてモールドパウダーを巻き込み、溶鋼の品質が低下するおそれがある。 Further, in the method (2) of immersing the probe directly in the molten steel in the mold, it is difficult to obtain continuous information on the molten steel temperature with a consumable thermocouple. In addition, even when a protective tube such as cermet is continuously immersed, the life of the protective tube is limited (1 hour to several hours) in an environment where the molten steel flow velocity is fast (about 0.1 to 0.5 m / s) as in the mold. However, the cost of the protective tube and replacement work are necessary for continuous measurement. In addition, in the method in which the probe is directly immersed in the molten steel in the mold, mold powder is entrained in the molten steel at the time of immersion, the metal bar attached around the probe is dropped into the molten steel, or the molten steel is surrounded around the immersed probe. There is a risk that flow vortices will be generated and mold powder will be entrained, and the quality of the molten steel will deteriorate.
又、（３）の鋳型間の溶鋼温度を間接的に測定する方法では、別途に冷却箱に耐熱窓ガラスを設けるため設備の改良及び、劣化した耐熱窓ガラスの交換が必要となりコストがかかる。 In addition, in the method (3) of indirectly measuring the molten steel temperature between the molds, a heat-resistant window glass is separately provided in the cooling box, so that it is necessary to improve the equipment and replace the deteriorated heat-resistant window glass.
本発明は、前記従来の問題点を解消すべくなされたもので、鋳型内の溶鋼に直接プローブ等を浸漬することなく、経時的に連続して測定が可能で、消耗品が極力少ないことを条件として、推定精度の良い鋳型内溶鋼温度の推定方法及び装置を提供することを課題とする。 The present invention has been made to solve the above-mentioned conventional problems, and can continuously measure over time without directly immersing a probe or the like in molten steel in a mold, and has as few consumables as possible. It is an object of the present invention to provide a method and an apparatus for estimating the molten steel temperature in the mold with good estimation accuracy as a condition.
本発明は、液体金属を冷却させ、凝固シェルを形成して固体金属になりつつある該液体金属の鋳片を鋳型から引抜く液体金属の連続鋳造に際し、鋳型出口における凝固シェルの厚みと該凝固シェル厚み方向の平均温度とを求める段階と、前記固体金属に関する温度とエンタルピーとの関係に基づいて前記平均温度から前記固体金属の単位量あたりエンタルピーである第１エンタルピーを求める段階と、鋳型の冷却水の入側と出側の温度差及び冷却水の流量により、前記液体金属から流出する全熱量に対応する鋳型内における総括熱流束を求める段階と、該総括熱流束、前記鋳片引抜き量、前記凝固シェル厚み及び前記鋳型出口での凝固シェルの平均密度から、前記液体金属から抜き去られたエンタルピー量である前記固体金属の単位量あたり抜去エンタルピー量を求める段階と、前記第１エンタルピーに前記抜去エンタルピー量を加算し、鋳型内に注入された時点での前記液体金属の単位量あたりエンタルピーである第２エンタルピーを求める段階と、前記液体金属に関する温度とエンタルピーとの関係に基づいて該第２エンタルピーから前記液体金属の温度を求める段階と、からなる連続鋳造鋳型内溶湯温度を推定方法により、前記課題を解決したものである。 The present invention cools a liquid metal, forms a solidified shell, and pulls out the liquid metal slab, which is becoming a solid metal, from the mold. a step of determining the average temperature of the shell thickness direction, and determining a first enthalpy is a unit per volume enthalpy of the solid metal from the average temperature on the basis of a relationship between the temperature and the enthalpy for said solid metal, cooling the mold The step of obtaining a total heat flux in the mold corresponding to the total amount of heat flowing out of the liquid metal by the temperature difference between the inlet side and the outlet side of the water and the flow rate of the cooling water, the overall heat flux, the amount of drawn slab, From the solid shell thickness and the average density of the solidified shell at the mold outlet, the unit amount of the solid metal that is the amount of enthalpy removed from the liquid metal And determining a enthalpically amount, adding the removal enthalpy quantity in the first enthalpy, and determining a second enthalpy wherein a unit amount per enthalpy of liquid metal when it is injected into the mold, the liquid The above-mentioned problem is solved by a method for estimating the temperature of the molten metal in the continuous casting mold, which comprises the step of obtaining the temperature of the liquid metal from the second enthalpy based on the relationship between the temperature related to the metal and the enthalpy.
又、本発明は、液体金属を冷却させ、凝固シェルを形成して固体金属になりつつある該液体金属の鋳片を鋳型から引抜く液体金属の連続鋳造における鋳型内溶湯温度の推定装置において、単位時間当たりの鋳片引抜き量を測定する手段と、鋳型出口における凝固シェルの厚みと該凝固シェル厚み方向の平均温度とを求める手段と、前記固体金属に関する温度とエンタルピーとの関係に基づいて前記手段で求められた平均温度から前記固体金属の単位量あたりエンタルピーである第１エンタルピーを求める手段と、鋳型の冷却水の入側と出側の温度差及び冷却水の流量を求める手段と、該測定された鋳型の冷却水の入側と出側の温度差及び冷却水の流量により、前記液体金属から流出する全熱量に対応する鋳型内における総括熱流束を求める手段と、該総括熱流束、前記鋳片引抜き量、前記凝固シェル厚み、及び前記鋳型出口での凝固シェルの平均密度から、前記液体金属から抜き去られたエンタルピー量である前記固体金属の単位量あたり抜去エンタルピー量を求める手段と、前記第１エンタルピーに前記抜去エンタルピー量を加算し、鋳型内に注入された時点での前記液体金属の単位量あたりエンタルピーである第２エンタルピーを求める手段と、前記液体金属に関する温度とエンタルピーとの関係に基づいて該第２エンタルピーから前記液体金属の温度を求める手段と、を具備することを特徴とする、連続鋳造鋳型内溶湯温度の推定装置により、前記課題を解決したものである。 Further, the present invention is an apparatus for estimating a molten metal temperature in a mold in a continuous casting of a liquid metal in which the liquid metal is cooled, and a solidified shell is formed to pull out the liquid metal slab that is becoming a solid metal from the mold. Based on the relationship between the means for measuring the slab drawing amount per unit time, the means for determining the thickness of the solidified shell at the mold outlet and the average temperature in the thickness direction of the solidified shell, and the temperature and enthalpy for the solid metal Means for obtaining a first enthalpy which is an enthalpy per unit amount of the solid metal from the average temperature obtained by the means, means for obtaining a temperature difference between the inlet side and the outlet side of the cooling water of the mold and a flow rate of the cooling water, Based on the measured temperature difference between the inlet side and the outlet side of the cooling water of the mold and the flow rate of the cooling water, the total heat flux in the mold corresponding to the total amount of heat flowing out of the liquid metal is obtained. And per unit amount of the solid metal that is the amount of enthalpy extracted from the liquid metal from the overall heat flux, the slab extraction amount, the solidified shell thickness, and the average density of the solidified shell at the mold outlet Means for obtaining an extraction enthalpy amount, means for adding the removal enthalpy amount to the first enthalpy, and obtaining a second enthalpy which is an enthalpy per unit amount of the liquid metal when injected into a mold; and the liquid Means for determining the temperature of the liquid metal from the second enthalpy based on the relationship between the temperature related to the metal and the enthalpy, and solves the above problem by an apparatus for estimating the temperature of the molten metal in the continuous casting mold It is a thing.
本発明によれば、単位時間当たりの鋳片引抜き量と、鋳型の冷却水の入側と出側の温度差と、冷却水の時間あたり流量とを測定し、金属に関する温度とエンタルピーとの関係を利用することで、鋳型内の溶鋼に直接プローブ等を浸漬することなく、消耗品が極力少なく、経時的に連続して推定精度の良い鋳型内溶鋼温度を推定することができる。 According to the present invention, the amount of slab drawing per unit time, the temperature difference between the inlet side and the outlet side of the cooling water in the mold, and the flow rate per hour of the cooling water are measured, and the relationship between the temperature related to metal and enthalpy By using the above, it is possible to estimate the molten steel temperature in the mold continuously with time and with high estimation accuracy without immersing the probe or the like directly in the molten steel in the mold, with as few consumables as possible.
したがって、鋳型内の溶鋼温度に起因する鋳片の品質異常や、鋳型内溶鋼温度を計算パラメータとして使用する技術計算、たとえば特許第３２３０５１３号にあるような鋳型内銅板温度から鋳型内の溶鋼流速を推定することが精度よく行うことができる。 Therefore, the quality of the slab due to the molten steel temperature in the mold and technical calculation using the molten steel temperature in the mold as a calculation parameter, for example, the molten steel flow velocity in the mold from the copper plate temperature in the mold as described in Japanese Patent No. 3230513 The estimation can be performed with high accuracy.
以下、図面を参照して、本発明に係る実施形態について説明する。 Embodiments according to the present invention will be described below with reference to the drawings.
図１は、本発明の１つの実施形態を示す連続鋳造機（垂直曲げ型の連続鋳造機）の断面の概略図である。なお、ここでは普通鋼のスラブ連鋳を対象として示した。 FIG. 1 is a schematic view of a cross section of a continuous casting machine (vertical bending type continuous casting machine) showing one embodiment of the present invention. In addition, the slab continuous casting of ordinary steel is shown here as an object.
図１において、連続鋳造機は、液体金属である溶鋼２を貯えるタンディッシュ４と、冷却しながら溶鋼２を型取る鋳型６と、溶鋼２が凝固しつつある鋳片８を鋳型６から引抜くピンチローラ１０とを有して構成されている。
In FIG. 1, the continuous casting machine pulls out a tundish 4 that stores
タンディッシュ４の先端側に、溶鋼２を鋳型６に注ぐ浸漬ノズル１２が設けられ、タンディッシュ４と浸漬ノズル１２の間には溶鋼湯面（メニスカス）１４のレベルが目標値に設定されるように、流量を調節するスライディングノズル１６が配置されている。
An
鋳型６には、冷却水路１８が配設され、冷却水路１８の入側に給水管２０、出側に排水管２２が連結されている。給水管２０及び排水管２２には夫々熱電対による第１水温計２４及び第２水温計２６が配置され、排水管２２には、電磁流量計２８が設置されている。
A
一部のピンチローラ１０には、鋳型６下端での鋳片引抜き速度を測定するための鋳片引抜き速度計３０が備えられている。
Some
鋳型６の銅板に、給水管２０から冷却水が通水され、冷却水路１８内を流れ、溶鋼２の熱が奪われ、奪われた熱は排水管２２を介して外へ排出される。
Cooling water is passed from the
第１温度計２４は、給水管２０の冷却水の温度を測定し、第２温度計２６は、排水管２２の中を流れる熱を奪った冷却水の温度を測定し、鋳型６の冷却水の入側と出側の温度差が求められる。
The
電磁流量計２８は、鋳型６から出て行く熱量を求めるため、排水管２２を流れる冷却水の流量を測定する。
The
鋳片引抜き速度計３０は、鋳型６出口での凝固シェル３２の厚み方向の平均温度を回帰式より求める（後述）ための独立変数等として必要な鋳造速度を測定する。
The slab
次に、本発明に係る鋳型６内の溶鋼２の温度を推定する方法について説明する。
Next, a method for estimating the temperature of the
まず鋳型６内での凝固の物理過程を考えると、浸漬ノズル１２から鋳型６内に注入された溶鋼２は顕熱と凝固潜熱を含めたあるエンタルピー（含熱量）を持っている。
First, considering the physical process of solidification in the mold 6, the
一方、鋳型６は一般に銅板内に配設された冷却水路１８内を流れる冷却水が溶鋼２からの熱移動分のほぼすべてを吸収しているとみてよい。
On the other hand, it can be considered that the mold 6 generally absorbs almost all of the heat transfer from the
したがって、冷却水の入側の温度と出側の温度との差に相当する熱量は、溶鋼２のエンタルピーから、鋳型６出口での凝固シェル３２の厚み方向平均温度でのエンタルピーまでの落差分に相当すると考えてよい。
Therefore, the amount of heat corresponding to the difference between the inlet side temperature and the outlet side temperature of the cooling water is a difference from the enthalpy of the
以下、上記の原理を使用して、鋳型冷却水入出温度差から求まる鋳型６の総括抜熱量から鋳型６内の溶鋼温度を求める手順を図２におけるフローチャート及び図３における温度とエンタルピーとの関係を示すグラフに基づいて詳細に説明する。 Hereinafter, a procedure for obtaining the molten steel temperature in the mold 6 from the overall heat removal amount of the mold 6 obtained from the mold cooling water inlet / outlet temperature difference using the above principle is shown in the flowchart in FIG. 2 and the relationship between the temperature and enthalpy in FIG. This will be described in detail based on the graph shown.
まず、連続鋳造機で扱う金属に関する温度とエンタルピーとの関係として、鋼の温度−エンタルピー曲線を決定する。これは一般に知られている温度毎の比熱データおよび凝固潜熱データより決定する（ステップＳ１）。図３において、温度とエンタルピーとの関係並びに温度推定の手順を模式的に示した。 First, a temperature-enthalpy curve of steel is determined as a relationship between temperature and enthalpy related to a metal handled by a continuous casting machine. This is determined from generally known specific heat data and solidification latent heat data for each temperature (step S1). FIG. 3 schematically shows the relationship between temperature and enthalpy and the temperature estimation procedure.
次に、鋳型６出口での凝固シェル３２の厚み方向の平均温度（Ｔ１ａｖｅ）を求める（ステップＳ２）。これには伝熱凝固計算を用い、想定される鋳造速度（＝鋳片引抜き速度）Ｖｃの範囲内で複数の水準で計算し、鋳造速度Ｖｃを独立変数、厚み方向の平均温度Ｔ１ａｖｅを説明変数とする回帰式を作成する。鋳造速度は、鋳片引抜き速度計３０で測定する。
Next, an average temperature (T1 ave ) in the thickness direction of the
平均温度Ｔ１ａｖｅを求めた後、鋼の温度とエンタルピーとの関係に基づいて、平均温度Ｔ１ａｖｅから第１エンタルピー（Ｈ１）を求める（ステップＳ３）。 After obtaining the average temperature T1 ave , the first enthalpy (H 1 ) is obtained from the average temperature T1 ave based on the relationship between the temperature of the steel and the enthalpy (step S3).
次に、鋳型冷却水入出温度差から、単位面積当りの鋳型内総括抜熱量である総括熱流束（Ｑ）を求める（ステップＳ４）。総括熱流束Ｑは次式で表される。 Next, the overall heat flux (Q), which is the overall heat removal amount in the mold per unit area, is obtained from the temperature difference between the mold cooling water input and output (step S4). The overall heat flux Q is expressed by the following equation.
ここで、
Ｑ：鋳型内総括熱束（Ｗ／ｍ２）、
ΔＴ：鋳型冷却水の入出温度差（℃）、
Ｒ：冷却水の時間あたり流量（ｍ３／ｓ）、
ｈ：鋳型のメニスカスから鋳型出口までの距離（ｍ）、
Ｗ：鋳型幅（ｍ）
である。
here,
Q: Overall heat flux in the mold (W / m 2 ),
ΔT: mold cooling water inlet / outlet temperature difference (° C),
R: Flow rate of cooling water per hour (m 3 / s),
h: distance from the meniscus of the mold to the mold outlet (m),
W: Mold width (m)
It is.
なお、入出温度差ΔＴは、給水管２０及び排水管２２に配置された水温計２４、２６より求める。熱の流出は主に鋳片８の鋳型幅Ｗと鋳型のメニスカスから鋳型出口までの距離ｈとの面からのものとする。
The inlet / outlet temperature difference ΔT is obtained from water temperature gauges 24 and 26 disposed in the
次に、（１）式で求めた総括熱流束Ｑから、鋳型６出口での凝固シェル単位重量当たりの、溶鋼２からのエンタルピー落差である抜去エンタルピー量（ΔＨ）を次の（２）式から求める（ステップＳ５）。
Next, from the general heat flux Q obtained by the equation (1), the removal enthalpy amount (ΔH), which is the enthalpy drop from the
ここで、
ρ：鋳型出口での凝固シェルの平均密度（ｋｇ／ｍ３）、
Ｖｃ：鋳型下端での鋳片引抜き速度（ｍ／ｓ）、
ｄ：鋳型下端での凝固シェル厚（ｍ）
であり、凝固シェル厚ｄは、伝熱凝固計算を用い、想定されるＶｃから求める。
here,
ρ: average density of solidified shell at the mold outlet (kg / m 3 ),
Vc: slab drawing speed at the lower end of the mold (m / s),
d: Solidified shell thickness at the lower end of the mold (m)
The solidified shell thickness d is obtained from the assumed Vc using heat transfer solidification calculation.
次に、鋳型６に注入された溶鋼２の第２エンタルピー（Ｈ２）を次の（３）式で求める（ステップＳ６）。
Next, the second enthalpy (H 2 ) of the
Ｈ２＝Ｈ１＋ΔＨ ・・・（３） H 2 = H 1 + ΔH (3)
次に、Ｈ２を段階Ｓ１の鋼の温度−エンタルピー曲線を用いて対応する温度に変換する（ステップＳ７）。これにより鋳型６内の溶鋼温度Ｔ２を求める。 Then, the temperature of the steel H 2 stages S1 - converted into the corresponding temperature with the enthalpy curve (step S7). Thereby, the molten steel temperature T2 in the mold 6 is obtained.
以上の手順によりＴ１ａｖｅは、鋳造速度Ｖｃから、総括熱流束Ｑは、鋳型冷却水の入出温度差ΔＴと冷却水の時間あたり流量Ｒから、抜去エンタルピー量ΔＨは、鋳型下端での鋳片引抜き速度Ｖｃとこの鋳片引抜き速度Ｖｃから求まる凝固シェル厚ｄから、夫々時々刻々求めることができるため、鋳型内の溶鋼温度Ｔ２を溶鋼に測温プローブ等を浸漬することなく、経時的に連続して推定することができる。しかも、直接プローブ等を溶鋼に浸漬することがないので、消耗品が極力少なくて済む。 By the above procedure, T1 ave is determined from the casting speed Vc, the overall heat flux Q is determined from the temperature difference ΔT of the mold cooling water and the flow rate R per hour of the cooling water, and the extraction enthalpy amount ΔH is determined by the slab extraction at the bottom of the mold Since the solidified shell thickness d obtained from the speed Vc and the slab drawing speed Vc can be obtained from time to time, the molten steel temperature T2 in the mold can be continuously increased over time without immersing a temperature measuring probe or the like in the molten steel. Can be estimated. In addition, since the probe or the like is not directly immersed in the molten steel, the number of consumables is minimized.
なお、連続鋳造機は完全垂直型、湾曲型など形式を問わない。 The continuous casting machine may be of any type such as a complete vertical type and a curved type.
又、通常は鋳型の長辺銅板、短辺銅板それぞれに独立して流量調節の可能となっている場合が多いが、銅板でまとめて１つの流量調節計でも問題は無い。 Usually, the flow rate can be adjusted independently for each of the long-side copper plate and the short-side copper plate of the mold, but there is no problem even if one flow rate controller is combined with the copper plate.
又、凝固シェルの厚み及び凝固シェルの厚み方向の平均温度は、伝熱凝固計算を用いて鋳造速度から求めているが、凝固シェルの厚みについては、例えば超音波を用いて測定し、前記平均温度については、鋳型直下での鋳片の表面温度を、例えば放射温度計で測定し、平均温度を推計してもよい。 The thickness of the solidified shell and the average temperature in the thickness direction of the solidified shell are obtained from the casting speed using heat transfer solidification calculation. The thickness of the solidified shell is measured using, for example, ultrasonic waves, and the average Regarding the temperature, the surface temperature of the slab immediately below the mold may be measured, for example, with a radiation thermometer, and the average temperature may be estimated.
次に、具体的にスラブ連鋳機に適用した本発明による実施例を示す。 Next, the Example by this invention applied to the slab continuous casting machine concretely is shown.
本実施例では表１に示すような成分の薄板用極低炭素鋼で行った。 In this example, the ultra low carbon steel for thin plates having the components shown in Table 1 was used.
スラブ連鋳機の装置構成の概略は上記の発明の実施形態同様に図１に示したものであり、表２に示すような鋳造条件で鋳造した。 The outline of the apparatus configuration of the slab continuous casting machine is shown in FIG. 1 as in the embodiment of the invention described above, and was cast under casting conditions as shown in Table 2.
図４は、鋳片引抜き速度計３０により測定された、鋳込み長さに対する鋳造速度Ｖｃの経時的トレンドデータを示したものである。
FIG. 4 shows time-dependent trend data of the casting speed Vc with respect to the casting length, measured by the slab
図５はタンディッシュ内溶鋼温度（スポット測定）及び、それと同じタイミングで測定した鋳型内の溶鋼温度のデータを示すもので、この鋳型内の溶鋼温度のデータは、本発明に係る推定方法により求めた鋳型内溶鋼温度の値との比較用として測定したものである。 FIG. 5 shows the molten steel temperature in the tundish (spot measurement) and the molten steel temperature data in the mold measured at the same timing. The molten steel temperature data in the mold is obtained by the estimation method according to the present invention. It was measured for comparison with the value of the molten steel temperature in the mold.
この温度の測定は、熱電対に透明石英保護管を被せたものを使用し、保護管の先端を湯面１４下８０ｍｍにまで浸漬させ行った。
The temperature was measured by using a thermocouple covered with a transparent quartz protective tube and immersing the tip of the protective tube to 80 mm below the
又、図６は、鋳型冷却水の入出側温度差ΔＴのデータから求めた、鋳型内総括熱流束Ｑのトレンドである。このデータは鋳型長辺の前後面のそれぞれの入出側温度差ΔＴを平均し、その値に対する総括熱流束Ｑを求めた。またデータは経時的にみた場合、スラブ１枚毎の平均値データである。 FIG. 6 shows the trend of the overall heat flux Q in the mold obtained from the data of the temperature difference ΔT on the inlet / outlet side of the mold cooling water. This data was obtained by averaging the inlet / outlet side temperature differences ΔT on the front and rear surfaces of the long side of the mold, and calculating the overall heat flux Q for that value. The data is average value data for each slab when viewed over time.
以下、実施形態で述べた手順にしたがって、鋳型内総括熱流束Ｑから鋳型内溶鋼温度Ｔ２を推定した方法について述べる。 Hereinafter, a method for estimating the molten steel temperature T2 in the mold from the overall heat flux Q in the mold according to the procedure described in the embodiment will be described.
ｉ）まず、鋼の温度−エンタルピー曲線は、図７に示した値を用い、データ間は直線補間とした（ステップＳ１に対応）。なお、値はキャリブレーションしたものである。 i) First, the value shown in FIG. 7 was used for the temperature-enthalpy curve of steel, and linear interpolation was performed between the data (corresponding to step S1). The values are calibrated.
ｉｉ）次に、鋳型出口での凝固シェル厚みの平均温度Ｔ１ａｖｅは、伝熱凝固計算を複数の鋳造速度で行ない、次の（４）式のように決定した（ステップＳ２に対応）。 ii) Next, the average temperature T1 ave of the solidified shell thickness at the mold outlet was determined by the following formula (4) by performing heat transfer solidification calculation at a plurality of casting speeds (corresponding to step S2).
Ｔ１ａｖｅ＝２８．７５×Ｖｃ＋１２３４．２７５・・・（４） T1 ave = 28.75 × Vc + 1234.275 (4)
ｉｉｉ）この平均温度Ｔ１ａｖｅから第１エンタルピーＨ１を求めた（ステップＳ３に対応）。 iii) The first enthalpy H 1 was determined from this average temperature T1 ave (corresponding to step S3).
ｉｖ）鋳型内冷却水入出温度差ΔＴから、鋳型内総括熱流束Ｑを計算するには（１）式を用いた（ステップＳ４に対応）。求めた鋳型内総括熱流束Ｑの経時トレンドは図６に示した通りである。 iv) Formula (1) was used to calculate the overall heat flux Q in the mold from the cooling water inlet / outlet temperature difference ΔT in the mold (corresponding to step S4). The obtained temporal trend of the overall heat flux Q in the mold is as shown in FIG.
ｖ）この鋳型内総括熱流束Ｑから抜去エンタルピー量ΔＨを求めた（ステップＳ５に対応）。 v) The extraction enthalpy amount ΔH was determined from the overall heat flux Q in the mold (corresponding to step S5).
ｖｉ）鋳型に注入された溶鋼の第２エンタルピーＨ２は（３）式によって求めた（ステップＳ６に対応）。 vi) The second enthalpy H 2 of the molten steel injected into the mold was determined by equation (3) (corresponding to step S6).
ｖｉｉ）最後に鋳型内の溶鋼温度Ｔ２は、図７に示されたような、鋼の温度とエンタルピーとの関係データを用い、段階ｖｉ）で求めた鋳型内の溶鋼の第２エンタルピーＨ２を温度Ｔ２に変換することで求めた（ステップＳ８に対応）。 vii) Finally, as the molten steel temperature T2 in the mold, the second enthalpy H 2 of the molten steel in the mold obtained in the step vi) is obtained by using the relationship data between the steel temperature and the enthalpy as shown in FIG. Obtained by converting to temperature T2 (corresponding to step S8).
このようにして求めた鋳型内の溶鋼温度の推定値Ｔ２を図８に示す。“◆”印のプロット列が本発明の鋳型内溶鋼温度の推定値Ｔ２であり、“●”印のプロットは図５にも示した、鋳型内溶鋼温度のスポット測定値である。 FIG. 8 shows the estimated value T2 of the molten steel temperature in the mold thus obtained. The plot line marked with “♦” is the estimated value T2 of the molten steel temperature in the mold of the present invention, and the plot marked with “●” is the spot measurement value of the molten steel temperature in the mold as shown in FIG.
両者はよく一致しており、本発明による鋳型内溶鋼温度の推定値Ｔ２をもって鋳型内の溶鋼温度の絶対値および時々刻々の変化を知ることができることがわかる。 Both are in good agreement, and it can be seen that the absolute value of the molten steel temperature in the mold and the change every moment can be known from the estimated value T2 of the molten steel temperature in the mold according to the present invention.
但し、図８を見てもわかるように、鋳造速度Ｖｃが変化している非定常部においては鋳型内溶鋼温度の推定値Ｔ２が異常となっている。これは、この実施例において鋳造速度Ｖｃは時々刻々の瞬時値を使用しているのに対し、鋳型内総括熱流束Ｑは、鋳型冷却水入出温度差ΔＴのスラブ切断単位データを使用しているためである。 However, as can be seen from FIG. 8, the estimated value T2 of the molten steel temperature in the mold is abnormal in the unsteady part where the casting speed Vc is changing. In this embodiment, the casting speed Vc uses an instantaneous value every moment, while the overall heat flux Q in the mold uses the slab cutting unit data of the mold cooling water inlet / outlet temperature difference ΔT. Because.
２…溶鋼
６…鋳型
８…鋳片
３２…凝固シェル
2 ... Molten steel 6 ...
Claims (2)
鋳型出口における凝固シェルの厚みと該凝固シェル厚み方向の平均温度とを求める段階と、
前記固体金属に関する温度とエンタルピーとの関係に基づいて前記平均温度から前記固体金属の単位量あたりエンタルピーである第１エンタルピーを求める段階と、
鋳型の冷却水の入側と出側の温度差及び冷却水の流量により、前記液体金属から流出する全熱量に対応する鋳型内における総括熱流束を求める段階と、
該総括熱流束、前記鋳片引抜き量、前記凝固シェル厚み、及び前記鋳型出口での凝固シェルの平均密度から、前記液体金属から抜き去られたエンタルピー量である前記固体金属の単位量あたり抜去エンタルピー量を求める段階と、
前記第１エンタルピーに前記抜去エンタルピー量を加算し、鋳型内に注入された時点での前記液体金属の単位量あたりエンタルピーである第２エンタルピーを求める段階と、
前記液体金属に関する温度とエンタルピーとの関係に基づいて該第２エンタルピーから前記液体金属の温度を求める段階と、
からなることを特徴とする、連続鋳造鋳型内溶湯温度の推定方法。 In the continuous casting of the liquid metal, the liquid metal is cooled, the solidified shell is formed, and the slab of the liquid metal that is becoming a solid metal is drawn from the mold,
Determining the thickness of the solidified shell at the mold outlet and the average temperature in the thickness direction of the solidified shell;
And determining a first enthalpy is a unit per volume enthalpy of the solid metal from the average temperature on the basis of a relationship between the temperature and the enthalpy for said solid metal,
Obtaining the overall heat flux in the mold corresponding to the total amount of heat flowing out of the liquid metal by the temperature difference between the inlet side and the outlet side of the cooling water of the mold and the flow rate of the cooling water;
Extraction enthalpy per unit amount of the solid metal, which is the amount of enthalpy extracted from the liquid metal from the overall heat flux, the slab extraction amount, the solidified shell thickness, and the average density of the solidified shell at the mold outlet Determining the quantity;
Adding the removal enthalpy amount to the first enthalpy and obtaining a second enthalpy that is an enthalpy per unit amount of the liquid metal at the time of being injected into the mold;
And determining a temperature of the liquid metal from the second enthalpy based on the relationship between the temperature and the enthalpy for said liquid metal,
A method for estimating a molten metal temperature in a continuous casting mold, comprising:
単位時間当たりの鋳片引抜き量を測定する手段と、
鋳型出口における凝固シェルの厚みと該凝固シェル厚み方向の平均温度とを求める手段と、
前記固体金属に関する温度とエンタルピーとの関係に基づいて前記手段で求められた平均温度から前記固体金属の単位量あたりエンタルピーである第１エンタルピーを求める手段と、
鋳型の冷却水の入側と出側の温度差及び冷却水の流量を求める手段と、
該測定された鋳型の冷却水の入側と出側の温度差及び冷却水の流量により、前記液体金属から流出する全熱量に対応する鋳型内における総括熱流束を求める手段と、
該総括熱流束、前記鋳片引抜き量、前記凝固シェル厚み、及び前記鋳型出口での凝固シェルの平均密度から、前記液体金属から抜き去られたエンタルピー量である前記固体金属の単位量あたり抜去エンタルピー量を求める手段と、
前記第１エンタルピーに前記抜去エンタルピー量を加算し、鋳型内に注入された時点での前記液体金属の単位量あたりエンタルピーである第２エンタルピーを求める手段と、
前記液体金属に関する温度とエンタルピーとの関係に基づいて該第２エンタルピーから前記液体金属の温度を求める手段と、
を具備することを特徴とする、連続鋳造鋳型内溶湯温度の推定装置。 In the apparatus for estimating the molten metal temperature in the mold in the continuous casting of the liquid metal in which the liquid metal is cooled, and the slab of the liquid metal that is forming a solid metal by forming a solidified shell is pulled out of the mold,
Means for measuring the amount of slab drawing per unit time;
Means for determining the thickness of the solidified shell at the mold outlet and the average temperature in the thickness direction of the solidified shell;
Means for determining a first enthalpy is a unit per volume enthalpy of the solid metal from the average temperature determined by said means on the basis of a relationship between the temperature and the enthalpy for said solid metal,
Means for determining the temperature difference between the inlet side and the outlet side of the mold cooling water and the flow rate of the cooling water;
Means for obtaining an overall heat flux in the mold corresponding to the total amount of heat flowing out of the liquid metal from the measured temperature difference between the inlet side and the outlet side of the cooling water of the mold and the flow rate of the cooling water;
The extraction enthalpy per unit amount of the solid metal, which is the amount of enthalpy extracted from the liquid metal, from the overall heat flux, the slab extraction amount, the solidified shell thickness, and the average density of the solidified shell at the mold outlet A means of determining the quantity;
Means for adding the removal enthalpy amount to the first enthalpy and obtaining a second enthalpy which is an enthalpy per unit amount of the liquid metal at the time of being injected into the mold;
It means for determining the temperature of the liquid metal from the second enthalpy based on the relationship between the temperature and the enthalpy for said liquid metal,
An apparatus for estimating a molten metal temperature in a continuous casting mold, comprising:
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| JP2950188B2 (en) * | 1995-02-21 | 1999-09-20 | 住友金属工業株式会社 | Method of controlling surface defects in continuous casting |
| JPH0952159A (en) * | 1995-08-15 | 1997-02-25 | Nippon Steel Corp | Continuous casting method |
| JPH11123515A (en) * | 1997-10-17 | 1999-05-11 | Sumitomo Electric Ind Ltd | Method for controlling solidification at initial stage in continuous casting |
| JP2000317594A (en) * | 1999-05-10 | 2000-11-21 | Nippon Steel Corp | Solidified shell thickness within molten metal casting mold and method for predicting powder inflow thickness |
| JP2001179413A (en) * | 1999-12-17 | 2001-07-03 | Sumitomo Metal Ind Ltd | Method for continuously casting steel |
| JP2002178117A (en) * | 2000-12-20 | 2002-06-25 | Kawasaki Steel Corp | Continuous casting method |
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| JP2007289977A (en) | 2007-11-08 |
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