JPS63207459A - Method for predicting breakout in continuous casting - Google Patents
Method for predicting breakout in continuous castingInfo
- Publication number
- JPS63207459A JPS63207459A JP4173187A JP4173187A JPS63207459A JP S63207459 A JPS63207459 A JP S63207459A JP 4173187 A JP4173187 A JP 4173187A JP 4173187 A JP4173187 A JP 4173187A JP S63207459 A JPS63207459 A JP S63207459A
- Authority
- JP
- Japan
- Prior art keywords
- mold temperature
- mold
- breakout
- threshold value
- standard deviation
- 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
Links
- 238000009749 continuous casting Methods 0.000 title claims description 14
- 238000000034 method Methods 0.000 title claims description 13
- 230000008859 change Effects 0.000 claims abstract description 23
- 238000005259 measurement Methods 0.000 claims description 7
- 238000005266 casting Methods 0.000 abstract description 17
- 230000005856 abnormality Effects 0.000 abstract description 9
- 229910000831 Steel Inorganic materials 0.000 description 5
- 230000006870 function Effects 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- 235000010627 Phaseolus vulgaris Nutrition 0.000 description 1
- 244000046052 Phaseolus vulgaris Species 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 235000021251 pulses Nutrition 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、連続鋳造用鋳型の温度変化を利用して鋳造中
に発生するブレークアウトを予知する方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for predicting breakouts occurring during casting by utilizing temperature changes in a continuous casting mold.
連続鋳造設備においてブレークアラ） （ＢＯ）が発生
し、鋳片内部の未凝固溶鋼が漏出した場合は、鋳造を停
止してブレークアウトを起した鋳片の排出及び溶鋼が付
着したロール等の設備の交換をする必要があり、相当の
期間に亘って操業の停止を余儀なくされる。このため、
ブレークアウトは連続鋳造の操業トラブルの中で最大の
ものであり、その防止対策の確立が望まれていた。If breakout (BO) occurs in continuous casting equipment and unsolidified molten steel inside the slab leaks, stop casting, drain the slab that has caused the breakout, and remove equipment such as rolls to which the molten steel has adhered. It will be necessary to replace the equipment, which will force the suspension of operations for a considerable period of time. For this reason,
Breakouts are the biggest operational trouble in continuous casting, and it has been desired to establish measures to prevent them.
ところで、引抜かれている鋳片の凝固殻が上下振動する
鋳型に固着して破断し、そこから溶鋼が漏出してこれが
十分に冷却される前に鋳型下端より出ることにより所謂
拘束性ブレークアウトが発生する場合は、凝固殻の破断
部が通過する鋳型部分では破断部の通過前に徐々に鋳型
温度が上昇し、破断部の通過後に徐々に降下することが
知られている。By the way, the solidified shell of the slab being drawn sticks to the vertically vibrating mold and breaks, and molten steel leaks out from the bottom of the mold before it is sufficiently cooled, causing a so-called restraint breakout. It is known that when this occurs, the temperature of the mold gradually increases in the mold portion where the broken part of the solidified shell passes before passing the broken part, and gradually decreases after passing the broken part.
このため、鋳型の銅板に熱電対等の測温素子を埋設して
これにて鋳型銅板の温度（以下これを鋳型温度という）
を測定し、測定した鋳型温度の単位時間当たりの変化率
を求めてその値と基準値との大小を監視するかく特開昭
５７−１１５９６２ ）、或いは測定した鋳型温度とそ
れ以前の鋳型温度の移動平均値との差を求めて、その値
と基準値との大小を監視することにより（特開昭５７−
１１５９５９ ） 、ブレークアウトを予知することは
一応可能である。For this reason, temperature measuring elements such as thermocouples are embedded in the copper plate of the mold to measure the temperature of the copper plate of the mold (hereinafter referred to as mold temperature).
(Japanese Patent Application Laid-open No. 57-115962), or by determining the rate of change of the measured mold temperature per unit time and monitoring the magnitude of that value and the reference value, or by comparing the measured mold temperature with the previous mold temperature. By determining the difference from the moving average value and monitoring the magnitude of that value and the reference value (Japanese Patent Application Laid-Open No. 1987-
115959), it is possible to predict a breakout.
ところで引抜速度が速い高速鋳造のときには安定鋳造時
及び異常発生時、つまり拘束性ブレークアウト発生時の
鋳型温度が共に高くなり、逆に低速鋳造のときには安定
鋳造時及び異常発生時の鋳型温度が共に低くなる。By the way, during high-speed casting where the drawing speed is high, the mold temperature is high both during stable casting and when an abnormality occurs, that is, when a restraining breakout occurs, and conversely, when low-speed casting is performed, the mold temperature during stable casting and when an abnormality occurs is both high. It gets lower.
このため、上述の監視方法によりブレークアウトを予知
する場合、高速鋳造時に低速鋳造時の予知に適当な低し
きい値を用いると、凝固殻の破断が実際には発生してい
ないときにもブレークアウトと誤って予知する頻度が高
くなり、また低速鋳造時に高速鋳造時の予知に適当な高
しきい値を用いると、凝固殻破断が発生してもそれを検
出できず見逃すことがあった。Therefore, when predicting breakout using the monitoring method described above, if an appropriate low threshold value is used to predict breakout during high-speed casting and low-speed casting, breakout will occur even when no rupture of the solidified shell has actually occurred. The frequency of erroneously predicting out was increased, and if a high threshold value suitable for prediction during high-speed casting was used during low-speed casting, even if a solidified shell fracture occurred, it could not be detected and was overlooked.
またブレークアウトを予知すると、一般に引抜を停止す
るか或いは引抜速度を相当遅くするため操業安定性が悪
く、鋳片品質が低下する。Furthermore, if a breakout is predicted, the drawing process is generally stopped or the drawing speed is considerably slowed down, resulting in poor operational stability and deterioration in slab quality.
本発明は斯かる事情に鑑みてなされたものであり、引抜
速度が異なる場合であっても高精度で拘束性ブレークア
ウトを予知できる方法を提供することを目的とする。The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method that can predict restraint breakout with high accuracy even when the withdrawal speeds are different.
本発明は、凝固殻が破断した場合において破断部分の鋳
型温度と鋳型振動（オノシレーション）により鋳片表面
に形成されたオノシレーションマークのピンチとが関連
し、またそのピンチが引抜速度又はそれと鋳型振動周期
とに関連することに着眼してしきい値を定め、また測定
した鋳型温度とそれ以前の平均鋳型温度との鋳型温度差
及び第１のしきい値と標準偏差との積の大小、測定した
鋳型温度の単位時間当たりの変化率と第２のしきい値の
大小、前記ＹＪｆ型温型温色差３のしきい値の大小、及
び測定鋳型温度と第４のしきい値との大小を監視する。In the present invention, when the solidified shell is fractured, the mold temperature at the fractured part is related to the pinch of the onoscillation mark formed on the surface of the slab due to mold vibration (onosilation), and the pinch is caused by the drawing speed or The threshold value is determined by focusing on the relationship between this and the mold vibration period, and the mold temperature difference between the measured mold temperature and the previous average mold temperature, and the product of the first threshold value and the standard deviation. size, the rate of change per unit time of the measured mold temperature and the second threshold value, the size of the threshold value of the YJf type warm color difference 3, and the measured mold temperature and the fourth threshold value. monitor the size of
即ち、本発明に係る連続鋳造におけるブレークアウト予
知方法は、上下振動する連続鋳造用鋳型の１又は２以上
の位置夫々で鋳型温度を時系列的に測定し、各測定時点
近傍での単位時間当たりの鋳型温度変化率と測定時点よ
り前の所定期間での鋳型温度の標準偏差及び平均温度と
を各位置毎に算出する一方、連続鋳造鋳片の引抜速度又
はそれと鋳型の振動周期とに基づき第１．第２．第３、
第４のしきい値を定め、各測定時点での鋳型温度と算出
した平均温度との差を求め、この鋳型温度差と第１のし
きい値及び標準偏差の積との大小比較、前記鋳型温度変
化率と第２のしきい値上の大小比軸、前記鋳型温度差と
第３のしきい値との大小比較、及び測定鋳型温度と第４
のしきい値との大小比較を行うことによりブレークアウ
トを予知することを特徴とする。That is, the breakout prediction method in continuous casting according to the present invention measures the mold temperature in time series at one or more positions of a vertically vibrating continuous casting mold, and calculates the temperature per unit time near each measurement point. The mold temperature change rate, the standard deviation and average temperature of the mold temperature during a predetermined period before the measurement time are calculated for each position, and the 1. Second. Third,
A fourth threshold value is determined, the difference between the mold temperature at each measurement point and the calculated average temperature is determined, and the difference in mold temperature is compared with the product of the first threshold value and the standard deviation, and the mold temperature is compared with the product of the first threshold value and the standard deviation. A magnitude ratio axis between the temperature change rate and the second threshold value, a magnitude comparison between the mold temperature difference and the third threshold value, and a magnitude comparison between the measured mold temperature and the fourth threshold value.
The feature is that a breakout is predicted by comparing the size with a threshold value.
以下本発明を図面に基づき具体的に説明する。 The present invention will be specifically explained below based on the drawings.
第１図は引抜速度（Ｖｃ）とオンシレージョンサイクル
（Ｃ）とが所定の関数（ｃ＝ｄ−Ｖ豆、ｄ：定数）を満
足する連続鋳造に本発明を適用した場合の実施状態を示
す模式図であり、図示しないタンディツシュに収容され
た溶鋼等の溶融金属１はその下に取付けられた浸漬ノズ
ル２を経て一定周期で上下にオソシレートしている鋳型
３へ装入される。鋳型３内の溶融金属１は、潤滑用の投
入パウダ６が鋳型３の内壁に沿って流れ込んで形成され
たパウダ膜を介して一次冷却されて凝固殻５を形成し、
これを周壁とする鋳片４は図示しないピンチロールによ
り下方に引抜かれていく。その引抜速度Ｖｃはパルスジ
ェネレータ９にて検出され、しきい値設定器１０へ与え
られる。Figure 1 shows the state of implementation when the present invention is applied to continuous casting where the drawing speed (Vc) and onillation cycle (C) satisfy a predetermined function (c = d - V bean, d: constant). Molten metal 1 such as molten steel stored in a tundish (not shown) is charged through a submerged nozzle 2 installed below into a mold 3 which is oscillated vertically at a constant period. The molten metal 1 in the mold 3 is primarily cooled through a powder film formed by a lubricating powder 6 flowing along the inner wall of the mold 3 to form a solidified shell 5.
The slab 4 having this as a peripheral wall is pulled downward by pinch rolls (not shown). The withdrawal speed Vc is detected by a pulse generator 9 and is provided to a threshold value setting device 10.
鋳型３の湯面レヘルよりも下には鋳片４の引抜方向（矢
符方向）に沿って３箇所に熱電対等の測温素子ＩＬ １
２．１３の先端が埋設されており、各測温素子１１．１
２．１３にて測定された鋳型温度ＴはＡ／Ｄ変換器１４
にてアナログ／ディジタル変換されて夫々微分回路２０
．３０．４０、減算器１５．２５．３５、平均温度算出
回路１６．２６．３６及び標準偏差算出回路１７．２７
．３７へ与えられる。Temperature measuring elements IL 1 such as thermocouples are installed at three locations below the hot water level of the mold 3 along the drawing direction (arrow direction) of the slab 4.
The tip of 2.13 is buried, and each temperature measuring element 11.1
2. The mold temperature T measured in 13 is measured by the A/D converter 14.
Analog/digital conversion is performed in the differentiator circuit 20.
．． 30.40, subtractor 15.25.35, average temperature calculation circuit 16.26.36 and standard deviation calculation circuit 17.27
．． Given to 37.
平均温度算出回路１６．２６．３６及び標準偏差算出回
路１７．２７．３７は夫々Ａ／Ｄ変換器１４からの入力
信号を例えば０．５秒乃至１秒の所定ピッチ（Ａｔ）で
取込む。この取込み信号については、鋳型３の周りに設
ける電磁攪拌装置等による雑音の影響を除去ずべく 、
Ａ／Ｄ変換器１４から例えば数１０ミリ秒ピンチで出力
される信号の複数個分の平均値を用いる。The average temperature calculation circuit 16.26.36 and the standard deviation calculation circuit 17.27.37 each take in the input signal from the A/D converter 14 at a predetermined pitch (At) of, for example, 0.5 seconds to 1 second. Regarding this intake signal, in order to eliminate the influence of noise caused by the electromagnetic stirring device etc. installed around the mold 3,
The average value of a plurality of signals outputted from the A/D converter 14 in a few tens of milliseconds, for example, is used.
そして、平均温度算出回路１６，２６．３６及び標準偏
差算出回路１７．２７．３７は最新の入力信号を含むそ
れ以前のｍ個分の入力信号を記４．ｑ、更新し、平均温
度算出回路１６．２６．３６は記憶している信号のうち
で記憶順位の若い方からｎ個分の信号の平均温度下を求
め、これを標準偏差算出回路１７．２７．３７及び減算
器１５．２５．３５へ与える。Then, the average temperature calculation circuits 16, 26.36 and the standard deviation calculation circuits 17, 27, and 37 record m input signals including the latest input signal. q, the average temperature calculation circuit 16.26.36 calculates the average temperature of n signals starting from the lowest storage order among the stored signals, and calculates the average temperature of n signals from the stored signals, and calculates this value to the standard deviation calculation circuit 17.27. .37 and subtractor 15.25.35.
減算器１５．２５．３５は入力した鋳型温度Ｔと平均温
度下との差（Ｔ−〒）を求め、これを比較器１９゜２９
、３９へ与える。The subtractor 15, 25, 35 calculates the difference (T-〒) between the input mold temperature T and the average temperature, and converts this to the comparator 19゜29.
, 39.
微分回路２０．３０．４０には夫々単位時間当たりの鋳
型温度変化率ｄＴ／ｄｔを数値微分により求めるべく、
公知の下記（１）式が設定されている。The differentiating circuits 20, 30, and 40 each have the following functions in order to obtain the mold temperature change rate dT/dt per unit time by numerical differentiation.
The following well-known formula (1) is set.
この（１）式は、ピッチΔｔで取込んだ鋳型温度のうち
、現測定時点での鋳型温度（Ｔｏ）とそれよりも１．
３． ４回前番こ取込んだ鋳型温度（Ｔ１゜Ｔｓ 、
Ｔａ ）の４つを用いて、鋳型温度変化率を算出するも
のである。This equation (1) is calculated by calculating the mold temperature (To) at the current measurement time and 1.
3. Mold temperature (T1゜Ts,
The mold temperature change rate is calculated using the following four values: Ta).
なお、上記（１）式のＴｏ、・・・、Ｔ４は取込みピッ
チ毎の測定値そのものを使用せずに複数の測定値が得ら
れる期間を複数設定してその各期間での平均値を用いて
もよい。また、鋳型温度変化率ｄＴ／ｄｔは上記＋１１
式に限らず他の微分係数を求める式を用いてもよい。In addition, To, ..., T4 in the above equation (1) do not use the measured value itself for each acquisition pitch, but set multiple periods in which multiple measured values can be obtained, and use the average value in each period. It's okay. In addition, the mold temperature change rate dT/dt is +11 above.
In addition to the formula, other formulas for calculating differential coefficients may be used.
微分回路２０．３０．４０は入力信号と上記（１）式と
により鋳型温度変化率ｄＴ／ｄｔを求めてこれを比較器
１９、２９．３９へ与える。The differentiating circuits 20, 30, 40 determine the mold temperature change rate dT/dt from the input signal and the above equation (1) and provide this to the comparators 19, 29, 39.
標準偏差算出回路１７．２７．３７は前同様のｎ個分の
信号の標準偏差σを求め、これを積算器１８．２８゜３
８へ与える。前記しきい値設定器１０はＶｃ及び下記（
２Ｌ （３）、 （４）弐に基づき第１．第２．第３の
しきい値に＋、Ｋｚ、Ｋａを算出し、Ｋ１を積算器１８
．２８゜３８へ与え、またＫｚ、に３を比較器１９，２
９．３９へ与える。The standard deviation calculation circuit 17.27.37 calculates the standard deviation σ of the n signals as before, and calculates the standard deviation σ of the n signals and sends it to the integrator 18.28゜3.
Give to 8. The threshold value setter 10 has Vc and the following (
2L (3), (4) Based on 2.1. Second. +, Kz, and Ka are calculated for the third threshold value, and K1 is added to the integrator 18.
．． 28° to 38, and 3 to Kz, to comparator 19, 2.
Give to 9.39.
Ｋｌ ＝ＡＩ ｘ７匠＋Ｂ、 ・・・（２）Ｋｇ
＝Ａ２ ｘＶ五十Ｂ２ ・・・（３）Ｋｓ ＝Ａ
３ ＸＩ／ＶＣ＋Ｂ：ｌ ”・（４１但し、Ａ、
：ｏ、ｉ 〜Ｉ （（’Ｃ／秒２）（分／ｍ））
Ｂ、：０．５〜３（’Ｃ／秒２）
Ａｔ ：０．１〜１ （’ｃ ・分／ｍ）Ｂ２ ：３〜
１５（’Ｃ）
Ａ３ ： ０．１〜１（分／ｍ）
Ｂ、：３〜１５
積算器１８．２８．３８はに１と標準偏差σとの積Ｋ。Kl = AI x7 Takumi + B, ... (2) Kg
=A2 xV50B2...(3)Ks =A
3 XI/VC+B:l ”・(41However, A,
:o,i ~I (('C/sec2)(min/m))
B: 0.5~3 ('C/sec2) At: 0.1~1 ('c min/m) B2: 3~
15('C) A3: 0.1-1 (min/m) B,: 3-15 Integrator 18.28.38 is the product K of 1 and the standard deviation σ.
・σを求めて比較器１９．２９．３９へ出力する。- Calculate σ and output to comparator 19, 29, 39.
比較器１９．２９．３９には下記（５１，＋６１． （
７）式が設定されており、比較器１９．２９．３９は、
入力した３種の信号が、取込みピッチ毎に＋５Ｌ （６
）、 ＋７＋式を各別に満足するか否かを判定し、例え
ば（２〜１０）秒をＩＢＯ判定期間としてその間に、（
５］、 ＋６）、 ＋７１各式を満足する時点がタイミ
ング的に異なってもすべて存在する場合、またはいずれ
か１つの式が成立する場合には警報器４１にて警報を発
せしめると共に、図示しない制御装置へ異常発生信号を
出力する。Comparator 19.29.39 has the following (51, +61. (
7) The formula is set, and the comparator 19.29.39 is
The input three types of signals are +5L (6
), +7+ formula is determined separately, and for example, (2 to 10) seconds is set as an IBO determination period, during which time (
5], +6), +71 If all of the points satisfying each equation exist even if they are different in timing, or if any one of the equations is satisfied, an alarm is issued by the alarm 41, and an alarm (not shown) is issued. Outputs an abnormality signal to the control device.
上記ＢＯ判定期間は取込みピッチ毎にそのピッチで移動
するように設ける。The above-mentioned BO determination period is provided so as to move at each capture pitch.
（Ｔ−〒）≧に１ ・σ ・・・（５）ｄ
Ｔ／ｄｔ≧に２ ・・・（６）
゛（Ｔ−〒）≧に３ ・・・（７）
なお、Ｋ＋ 、に２ 、に３については、凝固殻の破断
開口部の上下方向長さくβ）がオソシレーションマーク
ピソチ（Ｐ）に応じて異なり、つまりＰが大であればβ
は大、逆にＰが小であればβは小となり、このような！
に基づいて凝固殻破断部の開口面積が定まり、更にこの
面積に基づいて鋳型温度が定まるため、Ｐ（−Ｖｃ／ｃ
）を規定する引抜速度Ｖｃとオソシレーションサイクル
Ｃとに基づく関数とする。但し、この実施例のようにｃ
＝ｄ−ｙ’Ｖｃの関係を有する連続鋳造の場合には、Ｖ
五
Ｐ ＝Ｖｃ／ ｃ ＝Ｖｃ／ （ｄ−１／Ｖｃ） ＝
□となるため、前記＋２１． （３１，（４１式はＣ
を項に含まないＶｃのみの関数となる。(T-〒)≧1 ・σ ... (5) d
T/dt≧2...(6)
゛(T-〒)≧3...(7)
For K+, 2, and 3, the vertical length β) of the fracture opening of the solidified shell differs depending on the oscillation mark pitch (P), that is, if P is large, β
is large, and conversely, if P is small, β is small, so like this!
Since the opening area of the solidified shell fracture is determined based on , and the mold temperature is determined based on this area, P(-Vc/c
) is a function based on the drawing speed Vc and the oscillation cycle C that define the oscillation cycle C. However, as in this example, c
In the case of continuous casting with the relationship of = d-y'Vc, V
5P = Vc/ c = Vc/ (d-1/Vc) =
□, so the above +21. (31, (Formula 41 is C
It is a function only of Vc which does not include .
また、（２Ｌ （３）、 （４１弐のＡ＋ 、Ａ２ 、
Ａ３ 、Ｂ＋ 。Also, (2L (3), (412 A+, A2,
A3, B+.
Ｂ、、Ｂ３は測温素子の埋込み位置、深さに応じて異な
る値を用いてもよい。B, , B3 may have different values depending on the embedded position and depth of the temperature measuring element.
そして、前記制御装置（図示せず）は異常発生信号を入
力すると、浸漬ノズル２の中途に設けたスライディング
ノズル部７を油圧シリンダ８にて駆動して、浸漬ノズル
２を一端閉じると共に図示しないピンチロールの回転を
停止する。これについては浸漬ノズル２を僅かに開けた
状態にすると共に引抜速度を相当低下させるようにして
もよい。When the control device (not shown) receives an abnormality occurrence signal, it drives the sliding nozzle section 7 provided in the middle of the immersion nozzle 2 with a hydraulic cylinder 8, closes one end of the immersion nozzle 2, and pinches the immersion nozzle 2 (not shown). Stop the rotation of the roll. In this regard, the immersion nozzle 2 may be left slightly open and the drawing speed may be considerably reduced.
このように構成された予知装置による本発明方法を以下
に説明する。The method of the present invention using the prediction device configured as described above will be explained below.
まず、上記ｍ、ｎを次のように定める。連続鋳造する鋼
種が中炭素鋼又は低炭素鋼である場合には、鋳型温度は
第２図（横軸に時間をとり縦軸に鋳型温度をとっている
）に示す如（温度変化に周期があり、その周期は約２０
〜３０秒である。なお、第２図は鋳型の上下方向に異な
る３位置での鋳型温度Ｔａ、 Ｔｂ、 Ｔｃについて示
している。このためｎは３０秒間に測定された信号のう
ち高精度で予知できる数、例えば０．５秒毎に記憶する
として約６０個に定める。First, the above m and n are determined as follows. When the steel type to be continuously cast is medium carbon steel or low carbon steel, the mold temperature is determined as shown in Figure 2 (time is plotted on the horizontal axis and mold temperature is plotted on the vertical axis). Yes, the period is about 20
~30 seconds. Note that FIG. 2 shows mold temperatures Ta, Tb, and Tc at three different positions in the vertical direction of the mold. For this reason, n is set to a number that can be predicted with high accuracy among the signals measured in 30 seconds, for example, about 60, assuming that the signals are stored every 0.5 seconds.
また、凝固殻が破断した部分を測定する場合は、第３図
に示す如く鋳型温度がピーク値に達してから上昇直前の
元の温度に戻るまでの時間が５〜１５秒である。このた
め、ｍはこの５〜１５秒に相当する温度変化期間が予知
に必要な期間に含まれないようにするのが良く、５〜１
５秒に上記３０秒を加えた３５〜４５秒間に連続的に測
定された信号のうち高精度で予知できるピンチの数、例
えば０．５秒毎に記憶するとして７０〜９０個に定める
。In addition, when measuring the part where the solidified shell is broken, the time from when the mold temperature reaches the peak value until it returns to the original temperature just before rising is 5 to 15 seconds, as shown in FIG. Therefore, m should be set so that the temperature change period equivalent to 5 to 15 seconds is not included in the period necessary for prediction, and m is 5 to 15 seconds.
The number of pinches that can be predicted with high accuracy among the signals continuously measured for 35 to 45 seconds (5 seconds plus the above 30 seconds) is determined to be 70 to 90, for example, to be stored every 0.5 seconds.
なお、Ｋ、 、 Ｋｇ 、 Ｋ、＋の稙については夫
々前記（２１，（３）、 ［４１弐に基づいて算出する
ようにしているが、丸鋳片を連続鋳造するときのように
鋳片寸法に応じて引抜速度及びオンシレージョンストロ
ークが所定値に定まっている場合には、鋳型寸法に基づ
き、引抜速度に応じて凝固殻破断が起こる臨界の温度変
化量、変化率に定めるようにしてもよい。この場合には
上位計算機を設けてこれから鋳型寸法又は鋳型寸法に基
づいて決定したしきい値を第１閏に破線矢符にて示すよ
うにしきい値設定器１０へ与えるようにする。鋳型寸法
を与える場合にはしきい値設定器１０にテーブルを設定
しておき、このテーブルに基づきしきい値を読出させる
。Note that the edges of K, , Kg, K, + are calculated based on the above (21, (3), [412), respectively, but when continuously casting round slabs, If the drawing speed and oncillation stroke are set to predetermined values depending on the dimensions, the critical temperature change amount and rate of change that will cause solidification shell rupture should be determined based on the mold dimensions and according to the drawing speed. In this case, a host computer is provided, and the mold dimensions or the threshold values determined based on the mold dimensions are supplied to the threshold setting device 10 as shown by the dashed arrow in the first leap. When giving mold dimensions, a table is set in the threshold setting device 10, and the threshold value is read out based on this table.
斯かる準備が終了すると、連続鋳造を開始し、その後引
抜を開始すると予知装置を作動させる。When such preparation is completed, continuous casting is started, and when drawing is started, the prediction device is activated.
測温素子１１．１２．１３にて各位置の鋳型温度Ｔが測
定されると、平均温度算出回路１６．２６．３６及び標
準偏差算出回路１７．２７．３７は鋳型温度Ｔ信号を記
憶し、記憶信号の数がｍ個となるまで演算を行わず、ま
た出力しない。そして、ｍ個目の信号が記憶されると、
そのうち記憶順位が若い方からｎ個分の信号の平均温度
下と標準偏差σを夫々算出し、出力する。When the mold temperature T at each position is measured by the temperature measuring element 11.12.13, the average temperature calculation circuit 16.26.36 and the standard deviation calculation circuit 17.27.37 store the mold temperature T signal, No calculation is performed or output until the number of stored signals reaches m. Then, when the m-th signal is stored,
The average temperature and standard deviation σ of n signals starting from the lowest memory order are calculated and output.
減算器１５．２５．３５はｍ個目に入力した鋳型温度Ｔ
と平均温度下との差（Ｔ−丁）を求める。また積算器１
８．２８．３８は定数に、と標準偏差σとの積（Ｋ、
・σ）を求める。Subtractor 15, 25, 35 is the m-th input mold temperature T
Find the difference (T-T) between the temperature and the average temperature. Also, totalizer 1
8.28.38 is a constant, and the product of standard deviation σ (K,
・Find σ).
微分回路２０．３０．４０はＡ／Ｄ変換器１４からの鋳
型温度に関する信号を入力すると、（１）式に基づいて
時間変化率ｄＴ／ｄｔを算出し、これを比較器１９゜２
９、３９へ与える。When the differential circuits 20, 30, and 40 receive a signal related to the mold temperature from the A/D converter 14, they calculate the time rate of change dT/dt based on equation (1), and calculate the time rate of change dT/dt using the comparator 19.
Give to 9, 39.
比較器１９．２９．３９は５種の入力信号、つまりＴ−
〒＋Ｋｌ ・σ、 ｄＴ／ｄｔ、 Ｋｚ 、 Ｒ３
が上記（５）。Comparators 19.29.39 accept five input signals, namely T-
〒+Kl ・σ, dT/dt, Kz, R3
is (5) above.
（６１，（７１式を満足するか否かを各式毎に判定する
。(61, (Determine whether the formula 71 is satisfied or not for each formula.
次いで、ｍ＋１個目以降の信号が平均温度算出回路１６
等及び標準偏差算出回路１７等に記憶されると、前同様
にして繰り返す。Next, the m+1th and subsequent signals are sent to the average temperature calculation circuit 16.
etc. and stored in the standard deviation calculation circuit 17, etc., the same procedure as before is repeated.
このようにして信号処理を行っている間に、比較器１９
等のいずれか１つにて成るＢＯ判定期間に、＋５１．
（６）、 ＋７１各式を満足する時点がタイミング的に
異なってもすべて存在すると判定されると、又はいずれ
か１つが存在すると判定されると、該当する比較器はブ
レークアウトと予知し、警報器４１にて警報を発せしめ
ると共に図示しない制御装置に異常発生信号を出力する
。While performing signal processing in this way, the comparator 19
+51.
(6), +71 If it is determined that all of the points that satisfy each equation exist even if the timing is different, or if it is determined that any one of them exists, the corresponding comparator predicts a breakout and issues an alarm. The device 41 issues an alarm and outputs an abnormality occurrence signal to a control device (not shown).
制御装置は前述の如くスライディングノズル部７及び図
示しないピッチロールを制御して一旦装入及び引抜を停
止する。As described above, the control device controls the sliding nozzle section 7 and the pitch roll (not shown) to temporarily stop charging and withdrawing.
これにより、凝固殻が破断してその破断部から未凝固溶
鋼が漏出してもブレークアウトを未然に防止できる。Thereby, even if the solidified shell is broken and unsolidified molten steel leaks from the broken part, breakout can be prevented.
なお、上記実施例ではブレークアウト予知の判定の１つ
を上記（５）式にて行っているが、本発明はこれに限ら
ず下記（８）式を用いてもよいことは勿論である。Note that in the above embodiment, one of the determinations of breakout prediction is made using the above equation (5), but the present invention is not limited to this, and it goes without saying that the following equation (8) may also be used.
（Ｔ−Ｔ）／σ≧に１ ・・・（８）
また、詳細には説明しなかったが、しきい値設定器１０
において下記（９）式でに４を定め、比較器１９゜２９
．３９において測定鋳型温度Ｔとの比較を示す下記α０
）式が満足する時点にブレークアウトの警報を警報器４
■から発してもよい。(T-T)/σ≧1...(8)
Although not explained in detail, the threshold setting device 10
4 is determined using the following equation (9), and the comparator 19°29
．． The following α0 shows a comparison with the measured mold temperature T in 39.
) Alarm 4 to issue a breakout alarm when the formula is satisfied.
It may be issued from ■.
Ｋ ａ ＝ Ａ ａ ｘ ｙ’匠＋Ｂ４ ・・・
（９）Ａ４ ：定数
Ｂ４ ；定数
Ｔ≧に４ ・・・００）〔効果〕
第１表は鋳片寸法が種々異なる丸鋳片鋳造のときに本発
明を適用した場合の予知的中回数、誤警報回数及びブレ
ークアウトの見逃し回数を、そのときの鋳片寸法（Ｒ１
＜Ｒ２＜Ｒ３＜Ｒ４＜Ｒ５。K a = A a x y' Takumi + B4...
(9) A4: constant B4; constant T≧4...00) [Effect] Table 1 shows the number of predicted intermediate times when the present invention is applied to casting round slabs with various slab sizes. The number of false alarms and the number of missed breakouts are calculated based on the slab size (R1) at that time.
<R2<R3<R4<R5.
Ｒ３＝ １．５Ｒ，）、基準引抜速度（Ｖｃ＋＞Ｖｃｇ
＞Ｖ Ｃ３＞ Ｖ Ｃ４＞ Ｖ ｃｓ ＋ Ｖ ｃ＋α
２Ｖ−ｓ）と共にまとめて示す表である。なお、比較の
ために、同一鋳片寸法、基準引抜速度のときにしきい値
を、高速鋳造時に適当な一定の高しきい値として設定し
てブレークアウトの予知を行う従来方法■による場合の
結果と、しきい値を低速鋳造時に適当な一定の引きしき
い値として設定してブレークアウトの予知を行う従来方
法Ｈによる場合の結果とを、夫々第２表、第３表に示す
。R3 = 1.5R,), standard drawing speed (Vc+>Vcg
>V C3> V C4> V cs + V c+α
2V-s). For comparison, here are the results of the conventional method (■) in which breakout is predicted by setting the threshold at a constant high threshold suitable for high-speed casting when the slab dimensions are the same and the reference drawing speed is the same. Tables 2 and 3 show the results of conventional method H, which predicts breakout by setting the threshold value as a constant pull threshold value suitable for low-speed casting.
第 １ 表
第２表
第３表
これらの表より理解される如く、従来方法Ｉによる場合
（第２表）には予知的中率〔−予知的中回数／（予知的
中回数士誤警報回数）〕が３８／４３＝９０．５ （％
）、見逃し率〔−見逃し回数／（予知的中回数＋見逃し
回数）〕が５ ／４３−１１．６％であり、見逃し率が
高かった。また、従来方法Ｈによる場合（第３表）には
予知的中率が５０．８％、見逃し率が０％であり、的中
率が悪かった。これに対して本発明による場合（第１表
）には予知的中率が８７．１％、見逃し率が０％であり
、凝固殻の破断発生を全く見逃すことなく、高い的中率
を得ることができた。Table 1 Table 2 Table 3 As can be understood from these tables, in the case of conventional method I (Table 2), the predictive accuracy rate [-Number of predictive accuracy/(Number of predictive accuracy false alarms) )] is 38/43=90.5 (%
), the missed rate [-number of missed times/(number of predictable times + number of missed times)] was 5/43-11.6%, and the missed rate was high. Furthermore, in the case of conventional method H (Table 3), the predictive accuracy rate was 50.8% and the missed rate was 0%, indicating a poor accuracy rate. On the other hand, in the case of the present invention (Table 1), the predictive accuracy rate is 87.1% and the missed rate is 0%, and a high accurate rate is obtained without overlooking the occurrence of breakage of the solidified shell at all. I was able to do that.
なお、上記実施例では引抜方向に異なる鋳型の３位置で
鋳型温度を測定しているが、本発明はこれに限らず、引
抜方向及びそれに直交する方向に拘わらずに１若しくは
２又は４以上の任意の位置での鋳型温度を測定してもブ
レークアウトを予知できることは勿論である。但し、鋳
型温度の引抜方向測定位置としては、凝固殻破断を検出
して操業条件を変更し、これによりブレークアウトを未
然に防止できる時間的に余裕のある位置にするのが好ま
しい。In the above embodiment, the mold temperature is measured at three different positions of the mold in the drawing direction, but the present invention is not limited to this. Of course, breakout can be predicted by measuring the mold temperature at any location. However, it is preferable to measure the temperature of the mold in the drawing direction at a position where there is enough time to detect breakage of the solidified shell and change the operating conditions, thereby preventing breakout.
また、本発明は測温素子を鋳型の上下方向に２個以上設
ける場合には、次のようにすると更に確実にブレークア
ウトを予知できる。Further, in the present invention, when two or more temperature measuring elements are provided in the vertical direction of the mold, breakout can be predicted more reliably by the following procedure.
鋳型の上下方向に複数設けた温度素子夫々にて凝固殻破
断部が時間差をもって検出されるとき、その移行時間ｔ
Ｂ （秒）は下記（９）式にて表わされることが一般に
知られている。When a solidified shell fracture is detected with a time difference by each of the temperature elements provided in the vertical direction of the mold, the transition time t
It is generally known that B (seconds) is expressed by the following equation (9).
ｌｌｃ
但し、Ｌ二上下方向に離隔した測温素子間距離ｅ：定数
（０，５〜０．９）
したがって、各測温素子からの信号を処理する各比較器
１９．２９．３９の出側にタイマ機能を有する演算器を
設け、上側の測温素子に関する比較器から凝固殻破断の
検出信号（前記異常発生信号の出力条件にて出力され、
異常発生信号とは異なる信号）を入力し、それからｔＢ
秒程度経たのちにその直下の測温素子に関する比較器か
ら同様の凝固殻破断の検出信号を入力するとブレークア
ウトと予知し、これにより警報を発し、また制御装置へ
異常発生信号を出力する。これにより、より確実にブレ
ークアウトを予知できる。llc However, the distance e between two temperature measuring elements separated in the vertical direction: constant (0.5 to 0.9) Therefore, the output side of each comparator 19, 29, 39 that processes the signal from each temperature measuring element A computing unit with a timer function is installed in the upper temperature sensing element, and a detection signal of solidified shell rupture (is output under the output condition of the abnormality occurrence signal,
A signal different from the abnormality occurrence signal) is input, and then tB
After about a second, if a similar detection signal of solidified shell rupture is inputted from the comparator for the temperature measuring element directly below it, a breakout is predicted, an alarm is issued, and an abnormality occurrence signal is output to the control device. This allows breakouts to be predicted more reliably.
以上詳述した如く本発明は、連続鋳造用鋳型の１又は２
以上の位置の鋳型温度を測定し、その測定時点での鋳型
温度及びそれ以前の所定期間での平均鋳型温度の鋳型温
度差及び第１のしきい値と標準偏差との積の大小比較、
鋳型温度変化率と第２のしきい値との大小比較及び前記
鋳型温度差と第３のしきい値との大小比較を行うので、
引抜速度が変化してもそれに影響を受けずに拘束性ブレ
ークアウトを確実に予知できると共に誤警報の回数を減
少でき、これにより信頼性の向上を図れ、また従来では
誤警報により操業条件を変更してこのために鋳片品質が
低下していたのを防止できる等価れた効果を奏する。As detailed above, the present invention provides one or two continuous casting molds.
measuring the mold temperature at the above positions, and comparing the mold temperature difference between the mold temperature at the time of measurement and the average mold temperature in a predetermined period before that, and the product of the first threshold value and the standard deviation;
Since the mold temperature change rate and the second threshold are compared in magnitude and the mold temperature difference and the third threshold are compared in magnitude,
Restrictive breakouts can be reliably predicted without being affected by changes in withdrawal speed, and the number of false alarms can be reduced, thereby improving reliability. Therefore, it is possible to prevent the deterioration of slab quality due to this, and an equivalent effect can be achieved.
第１図は本発明の実施状態を示す模式図、第２回は鋳型
温度変化の周期の説明図、第３図は本発明の標準偏差、
平均温度を算出する期間の説明図である。Fig. 1 is a schematic diagram showing the implementation state of the present invention, the second is an explanatory diagram of the period of mold temperature change, and Fig. 3 is the standard deviation of the present invention,
FIG. 3 is an explanatory diagram of a period during which average temperature is calculated.
Claims (1)
夫々で鋳型温度を時系列的に測定し、各測定時点近傍で
の単位時間当たりの鋳型温度変化率と測定時点より前の
所定期間での鋳型温度の標準偏差及び平均温度とを各位
置毎に算出する一方、連続鋳造鋳片の引抜速度又はそれ
と鋳型の振動周期とに基づき第１、第２、第３、第４の
しきい値を定め、各測定時点での鋳型温度と算出した平
均温度との差を求め、この鋳型温度差と第１のしきい値
及び標準偏差の積との大小比較、前記鋳型温度変化率と
第２のしきい値との大小比較、前記鋳型温度差と第３の
しきい値との大小比較、及び測定鋳型温度と第４のしき
い値との大小比較を行うことによりブレークアウトを予
知することを特徴とする連続鋳造におけるブレークアウ
ト予知方法。 ２、前記鋳型温度差が第１のしきい値と標準偏差との積
よりも大きく、また前記鋳型温度変化率が第２のしきい
値よりも大きく、更に前記鋳型温度差が第３のしきい値
よりも大きく、更にまた、測定鋳型温度が第４のしきい
値よりも大きいいずれか一つ以上成立する場合にブレー
クアウトと判定する特許請求の範囲第１項記載の連続鋳
造におけるブレークアウト予知方法。 ３、鋳型の上下方向２位置以上において、夫々前記鋳型
温度差が第１のしきい値と標準偏差との積よりも大きく
、また前記鋳型温度変化率が第２のしきい値よりも大き
く、更に前記鋳型温度差が第３のしきい値よりも大きく
、更にまた、測定鋳型温度が第４のしきい値よりも大き
いいずれか一つ以上成立する場合にブレークアウトと判
定する特許請求の範囲第１項記載の連続鋳造におけるブ
レークアウト予知方法。[Claims] 1. Measure the mold temperature in time series at one or more positions of a continuous casting mold that vibrates vertically, and measure the mold temperature change rate per unit time in the vicinity of each measurement point. The standard deviation and average temperature of the mold temperature for a predetermined period before the point in time are calculated for each position, while the first, second, and third , a fourth threshold value is determined, the difference between the mold temperature at each measurement point and the calculated average temperature is determined, and the size of this mold temperature difference is compared with the product of the first threshold value and the standard deviation. Comparing the mold temperature change rate with a second threshold, comparing the mold temperature difference with a third threshold, and comparing the measured mold temperature with a fourth threshold; A breakout prediction method in continuous casting, characterized by predicting a breakout. 2. The mold temperature difference is larger than the product of the first threshold value and the standard deviation, and the mold temperature change rate is larger than the second threshold value, and furthermore, the mold temperature difference is larger than the product of the first threshold value and the standard deviation. A breakout in continuous casting according to claim 1, wherein a breakout is determined when one or more of the following conditions holds true: the measured mold temperature is greater than a threshold value, and the measured mold temperature is greater than a fourth threshold value. Prediction method. 3. At two or more positions in the vertical direction of the mold, the mold temperature difference is larger than the product of the first threshold value and the standard deviation, and the mold temperature change rate is larger than the second threshold value, A breakout is determined when one or more of the above-mentioned mold temperature difference is larger than a third threshold value and furthermore, the measured mold temperature is larger than a fourth threshold value. The method for predicting breakout in continuous casting as described in item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4173187A JP2668872B2 (en) | 1987-02-24 | 1987-02-24 | Breakout prediction method in continuous casting. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4173187A JP2668872B2 (en) | 1987-02-24 | 1987-02-24 | Breakout prediction method in continuous casting. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63207459A true JPS63207459A (en) | 1988-08-26 |
| JP2668872B2 JP2668872B2 (en) | 1997-10-27 |
Family
ID=12616567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4173187A Expired - Fee Related JP2668872B2 (en) | 1987-02-24 | 1987-02-24 | Breakout prediction method in continuous casting. |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2668872B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020156813A1 (en) * | 2019-02-01 | 2020-08-06 | Norsk Hydro Asa | Casting method and casting apparatus for dc casting |
| CN115178721A (en) * | 2022-06-07 | 2022-10-14 | 武汉钢铁有限公司 | Method, recording medium and system for controlling drawing speed of steel billet in continuous casting crystallizer |
-
1987
- 1987-02-24 JP JP4173187A patent/JP2668872B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020156813A1 (en) * | 2019-02-01 | 2020-08-06 | Norsk Hydro Asa | Casting method and casting apparatus for dc casting |
| CN113382814A (en) * | 2019-02-01 | 2021-09-10 | 诺尔斯海德公司 | Casting method and casting apparatus for DC casting |
| US11376654B2 (en) | 2019-02-01 | 2022-07-05 | Norsk Hydro Asa | Casting method and casting apparatus for DC casting |
| CN115178721A (en) * | 2022-06-07 | 2022-10-14 | 武汉钢铁有限公司 | Method, recording medium and system for controlling drawing speed of steel billet in continuous casting crystallizer |
| CN115178721B (en) * | 2022-06-07 | 2023-05-26 | 武汉钢铁有限公司 | Method, recording medium and system for controlling billet drawing speed in continuous casting crystallizer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2668872B2 (en) | 1997-10-27 |
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