JPH0815645B2 - Preventing cracking breakout in continuous casting - Google Patents
Preventing cracking breakout in continuous castingInfo
- Publication number
- JPH0815645B2 JPH0815645B2 JP2267783A JP26778390A JPH0815645B2 JP H0815645 B2 JPH0815645 B2 JP H0815645B2 JP 2267783 A JP2267783 A JP 2267783A JP 26778390 A JP26778390 A JP 26778390A JP H0815645 B2 JPH0815645 B2 JP H0815645B2
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- Prior art keywords
- mold
- breakout
- cracking
- continuous casting
- casting
- Prior art date
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Description
【発明の詳細な説明】 〈産業上の利用分野〉 この発明は、連続鋳造において特に中炭材を製造する
に際し、鋳型内不均一凝固に起因して鋳型直下で割れに
より漏鋼ブレークアウトに至割れ性ブレークアウトの防
止方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention, particularly in the production of medium carbonaceous materials in continuous casting, leads to a steel leak breakout due to cracking immediately below the mold due to uneven solidification in the mold. The present invention relates to a method for preventing breakable breakout.
〈従来技術〉 連続鋳造は、鋳型内に鋳込まれた溶鋼を鋳型により一
次冷却して溶鋼表面に凝固シェルを形成し、続く二次冷
却帯で案内支持しつつ前記凝固シェルを成長させて鋳片
を連続的に製造する方法であり、このような連続鋳造の
最大の操業トラブルとして、凝固シェルの破断により溶
鋼が漏出するブレークアウトがある。<Conventional technology> Continuous casting is a method in which the molten steel cast in the mold is primarily cooled by the mold to form a solidified shell on the surface of the molten steel, and the solidified shell is grown while being guided and supported by the subsequent secondary cooling zone. This is a method of continuously manufacturing the pieces, and the biggest operational trouble in such continuous casting is breakout in which molten steel leaks due to breakage of the solidified shell.
このようなブレークアウトは、発生すると多大の損害
を与えるため、その発生を未然に予知し、防止する必要
があり、また鋳造速度の高速化に伴いブレークアウトの
予知・防止が極めて重要となってきている。When such a breakout occurs, it causes a great deal of damage, so it is necessary to predict and prevent the occurrence of such breakout.In addition, as the casting speed increases, the prediction and prevention of breakout become extremely important. ing.
ブレークアウトの予知・防止方法は、従来から種々提
案されており、例えば次のような方法がある。Various breakout prediction / prevention methods have been conventionally proposed, for example, the following methods.
（ｉ） 特公昭59−46703号 鋳型の軸方向に温度検出素子を多数配設して鋳型温度
を検出し、複数個の隣接する温度検出素子の鋳型温度が
定常水準から高温側へ急激に偏いすることにより、凝固
シェルの破断あるいはブレークアウトの発生を予知する
方法。(I) JP-B-59-46703 A large number of temperature detecting elements are arranged in the axial direction of the mold to detect the mold temperature, and the mold temperature of a plurality of adjacent temperature detecting elements is rapidly deviated from the steady level to the high temperature side. This is a method of predicting the occurrence of breakage or breakout of the solidified shell.
（ii） 特開平２−52158号 相対する鋳型短辺に温度検出素子を埋設し、相対する
両短辺の温度値の偏差から、浸漬ノズルからの偏った吐
出流に起因する偏流性ブレークアウトを検知する方法。(Ii) Japanese Unexamined Patent Publication No. 2-52158 A temperature detecting element is embedded in opposite short sides of a mold, and a drift breakout caused by a biased discharge flow from a dipping nozzle is determined from the deviation of the temperature values of the opposite short sides. How to detect.
（iii） 特開昭60−191648号 鋳型直下に表面温度検出器を配設して鋳型直下におけ
る鋳片の軸方向温度分布を測定し、正常時の温度分布と
比較し、温度分布の異常または温度分布の時間的変化の
異常により二重肌や拘束性ブレークアウトを検知する方
法。(Iii) Japanese Unexamined Patent Publication No. 60-191648 A surface temperature detector is arranged immediately below the mold to measure the axial temperature distribution of the slab directly below the mold and compare it with the temperature distribution under normal conditions to determine whether the temperature distribution is abnormal or abnormal. A method to detect double skin and restraint breakout due to abnormal changes in temperature distribution over time.
（iv） 特開昭57−14449号 モールドとサポートロール群との間の鋳片の短辺形状
を測定し、測定値と基準値を比較することによりブレー
クアウトを検知する方法。(Iv) JP-A-57-14449 A method of detecting breakout by measuring the short side shape of a cast piece between a mold and a support roll group and comparing the measured value with a reference value.
〈この発明が解決しようとする課題〉 ブレークアウトは、鋳型と凝固シェルが焼き付くこと
によって発生する拘束性ブレークアウト、凝固シェル表
面が鋳型直下で割れることによって発生する割れ性ブレ
ークアウト、パウダーが鋳型と凝固シェルの間に過剰に
流入することによって発生するパウダー巻き込み性ブレ
ークアウトに大別されるが、（ｉ）の方法は、主に鋳型
内での焼付破断を伴った拘束性ブレークアウトの防止方
法であり、これでは、鋳型内でシェル破断を伴わず鋳型
直下にて横割れ、漏鋼が発生する中炭材鋳造時における
割れ性ブレークアウトを精度良く検出することはできな
い。<Problems to be solved by the present invention> Breakout is a constraining breakout that occurs when the mold and the solidified shell are seized, a breakable breakout that occurs when the surface of the solidified shell is cracked just below the mold, and a powder is the mold. It is roughly classified into powder entrainment breakout caused by excessive inflow between solidified shells, but the method (i) is mainly a method of preventing restraint breakout accompanied by seizure break in the mold. Therefore, it is not possible to accurately detect a cracking breakout during medium carbonaceous material casting in which lateral cracking occurs immediately below the mold without causing shell breakage in the mold and leakage steel occurs.
また、（ii）の方法も、浸漬ノズルからの偏流が無い
場合、同様に検出することはできない。Also, the method (ii) cannot be similarly detected when there is no drift from the immersion nozzle.
一方、鋳型直下にて凝固シェル生成状況を確認する
（ii）、（iv）の方法においては、高温・高湿下での検
出器の耐久性の問題があると共に、ブレークアウト発生
危険部分が鋳型下端へきてからの検出であるため、検出
後のブレークアウト防止が難しいという問題がある。On the other hand, in the methods (ii) and (iv) in which the state of solidified shell formation is confirmed directly under the mold, there is a problem with the durability of the detector under high temperature and high humidity, and the risk of breakout occurs in the mold. Since the detection is performed after reaching the lower end, there is a problem that it is difficult to prevent breakout after the detection.
この発明は、前述のような問題点を解消すべくなされ
たもので、その目的は、中炭材鋳造時に鋳型直下での割
れにより発生する割れ性ブレークアウトを、鋳型上部で
の検出により、容易かつ確実に防止することのできる連
続鋳造の割れ性ブレークアウト防止方法を提供すること
にある。The present invention has been made to solve the above-mentioned problems, and an object thereof is to easily detect a crackable breakout caused by a crack immediately below a mold during medium carbonaceous material casting by detecting it at the upper part of the mold. Another object of the present invention is to provide a method for preventing breakable breakout in continuous casting that can be reliably prevented.
〈課題を解決するための手段〉 本発明は、第１図、第２図に示すように、中炭材の連
続鋳造における鋳型内の不均一凝固に起因して鋳型直下
での割れにより発生する割れ性ブレークアウトの防止方
法であって、鋳型の短辺近傍の湯面レベルを湯面検出セ
ンサー７（例えば渦流センサー）で測定し、この鋳型短
辺近傍における局所的な単位時間当たりの湯面レベル変
動量Aiと、予め設定した割れ性ブレークアウト発生を防
止できる前記湯面レベル変動量の上限値A0とを、異常検
出装置８にて比較し、Ai＞A0の場合、鋳造速度Ｖを低下
させるようにしたものである。<Means for Solving the Problems> The present invention, as shown in FIGS. 1 and 2, is caused by cracking just below the mold due to uneven solidification in the mold in continuous casting of medium carbonaceous material. A method for preventing cracking breakout, in which the molten metal level near the short side of the mold is measured by a molten metal level detection sensor 7 (for example, an eddy current sensor), and the molten metal level per unit time is locally measured near this mold short side. The level fluctuation amount A i is compared with a preset upper limit value A 0 of the level fluctuation level of the molten metal surface capable of preventing the occurrence of a crackable breakout, and when the abnormality detection device 8 compares A i > A 0 , casting is performed. The speed V is reduced.
鋳造速度Ｖは、Ai≦A0となるViまで低下させるか、ま
たは所定下限速度V0まで低下させるようにする。The casting speed V is lowered to V i where A i ≦ A 0 , or is lowered to a predetermined lower limit speed V 0 .
また、鋳造速度Ｖの低下は、鋳造速度制御装置９によ
る自動減速、あるいはモニター10の監視によるオペレー
ター手動減速の何れでもよい。The casting speed V may be reduced by either automatic deceleration by the casting speed controller 9 or manual deceleration by the monitor 10 by the monitor 10.
〈作 用〉 割れ性ブレークアウトは、一定の鋼種に発生する現象
であり、第４図に示すように、〔Ｃ〕濃度0.09〜0.15％
の中炭材に発生している。この〔Ｃ〕濃度の鋼は、一般
的に鋳片の面縦割れ発生率が高いことが知られており、
凝固シェルの不均一生成を起こし易い鋼種である。<Working> Cracking breakout is a phenomenon that occurs in certain steel types. As shown in Fig. 4, [C] concentration is 0.09 to 0.15%.
It occurs in the medium carbonaceous material. It is generally known that the steel having this [C] concentration has a high incidence of longitudinal vertical cracking of the slab,
It is a steel type that tends to cause non-uniform formation of solidified shells.
このような鋼種の鋳造中、鋳型短辺近傍（短辺より10
0mm以内）の湯面レベル変動の発生が大きくなると、鋳
込方向の凝固シェルの不均一生成度が大きくなり、凝固
遅れ部が発生する。この凝固遅れ部の鋳型直下でのシェ
ル厚が、凝固が正常に進んだシェルの厚い部分の1/2以
下となった場合、第３図に示すように、凝固遅れ部より
横割れＡが発生し、ブレークアウトする危険がある。During casting of such steel types, near the short side of the mold (10
When the fluctuation of the molten metal surface level (within 0 mm) becomes large, the non-uniformity of the solidification shell in the casting direction becomes large, and the solidification delay portion occurs. When the thickness of the shell immediately below the solidification delay portion is less than 1/2 of the thick portion of the shell where solidification has proceeded normally, lateral cracking A occurs from the solidification delay portion, as shown in FIG. And there is a risk of breaking out.
湯面レベル変動と凝固シェル不均一生成度とは、第５
図に示すような関係があり、湯面レベル変動量が上限値
A0（この図では5mm/sec）に達すると、横割れ性ブレー
クアウトが発生する危険がある。従って、鋳型短辺近傍
（100mm以内）に湯面検出センサー７を設置して湯面変
動量を測定し、これが上限値A0に達すると、異常検出装
置８から警報を出力し、鋳造速度を自動または手動で下
げることにより、割れ性ブレークアウトを防止すること
ができる。The fluctuation of molten metal level and the degree of non-uniformity of solidification shell are
There is a relationship as shown in the figure, and the fluctuation level of the molten metal level is the upper limit.
When it reaches A 0 (5 mm / sec in this figure), there is a risk of lateral cracking breakout. Therefore, the melt level detection sensor 7 is installed near the short side of the mold (within 100 mm) to measure the melt level fluctuation amount, and when it reaches the upper limit value A 0 , an alarm is output from the abnormality detection device 8 to change the casting speed. Automatic or manual lowering can prevent breakable breakouts.
鋳造速度を下げる場合、鋳造速度変化による湯面変動
が必ず発生するので、横割れ性ブレークアウトが発生し
ない安全速度、つまり凝固シェルの不均一凝固が発生し
たとしても、凝固遅れ部のシェル厚が例えば10mm以上と
なる下限速度V0（例えば1.2m/min、第６図参照）まで低
下させ、湯面レベル安定後、再び湯面レベル変動量Aiが
上限値A0以下になる範囲で増速し、鋳造を継続するのが
好ましい。When lowering the casting speed, the fluctuation of the molten metal level will always occur due to the change of the casting speed. For example, after lowering to a lower limit speed V 0 (for example, 1.2 m / min, see FIG. 6) that is 10 mm or more, and after the molten metal level stabilizes, increase again in the range where the molten metal level fluctuation amount A i becomes the upper limit value A 0 or less. It is preferable to speed up and continue casting.
〈実 施 例〉 以下、この発明を図示する一実施例に基づいて説明す
る。第２図に示すように、連続鋳造設備は、取鍋１内の
溶鋼５をタンディッシュ２、浸漬ノズル３を介して鋳型
４内に鋳込み、案内支持ロール群６で案内支持しつつ駆
動ロール6Aにより速度Ｖで引き抜くようにされている。
鋳型は一対の長辺4Aと一対の短辺4Bを組み合わせた組立
鋳型となされている。<Example> Hereinafter, the present invention will be described based on an illustrated example. As shown in FIG. 2, in the continuous casting equipment, the molten steel 5 in the ladle 1 is cast into the mold 4 through the tundish 2 and the dipping nozzle 3, and the drive roll 6A is guided and supported by the guide support roll group 6. Is to be pulled out at a speed V.
The mold is an assembled mold in which a pair of long sides 4A and a pair of short sides 4B are combined.
このような構成において、両方の鋳型短辺4Bの表面か
ら100mm以内に渦流センサー７をそれぞれ設置し、両短
辺近傍における湯面レベルを測定する。In such a configuration, the eddy current sensors 7 are respectively installed within 100 mm from the surfaces of both short sides 4B of the mold, and the molten metal level in the vicinity of both short sides is measured.
渦流センサー７の検出信号は、異常検出装置８に出力
し、異常検出装置８では、単位時間当りの湯面レベル変
動量Aiと予め設定した割れ性ブレークアウト発生を防止
できる上限値A0、例えば５〔mm/sec〕と比較し、Ai＞A0
の場合、鋳造速度制御装置９により鋳造速度Ｖを低下さ
せ、またモニター10に検出結果、処理結果等を表示す
る。The detection signal of the eddy current sensor 7 is output to the abnormality detection device 8, and in the abnormality detection device 8, the level fluctuation A i of the molten metal surface per unit time and the preset upper limit value A 0 that can prevent the occurrence of cracking breakout, For example, comparing with 5 [mm / sec], A i > A 0
In the case of 1, the casting speed V is decreased by the casting speed control device 9, and the detection result, the processing result, etc. are displayed on the monitor 10.
鋳造速度制御装置９は、凝固遅れ部のシェル厚が10mm
以上となる下限速度V0、例えば1.2〔m/min〕まで低下さ
せ、湯面レベル安定後、AiがA0以下になる範囲で増速し
て鋳造を継続するよう駆動ロール6Aを制御する。The casting speed control device 9 has a shell thickness of 10 mm in the solidification delay part.
The lower limit speed V 0 becomes the above, for example, 1.2 (m / min) is lowered, and after the molten metal surface level stabilizes, the drive roll 6A is controlled so as to continue the casting by accelerating in the range where A i is A 0 or less. .
以上のような構成の装置を用いて、次のような条件で
本発明を実施したところ、第７図に示す結果が得られ
た。When the present invention was carried out under the following conditions using the apparatus having the above configuration, the results shown in FIG. 7 were obtained.
第７図に示すように、本発明実施前においては、中炭
材の割れ性ブレークアウトが年に５件程度発生していた
が、本発明を実施することにより、中炭材の割れ性ブレ
ークアウトを完全に防止することができた。本発明は、
〔Ｃ〕濃度0.09〜0.15％の割れ性ブレークアウト発生鋼
種のみに適用することにより、割れ性ブレークアウトを
確実に予知し、防止することができる。 As shown in FIG. 7, before the present invention was implemented, about 5 cracking breakouts of the medium carbonaceous material occurred annually. I was able to prevent out completely. The present invention
[C] By applying only to the steel type with cracking breakout having a concentration of 0.09 to 0.15%, the cracking breakout can be predicted and prevented without fail.
〈発明の効果〉 前述の通り、本発明は、中炭材鋳造時に鋳型直下での
割れにより発生する割れ性ブレークアウトを防止するに
際し、鋳型の短辺近傍の湯面レベルを測定し、湯面レベ
ル変動量が予め設定した上限値を越えると、鋳造速度を
低下させるようにしたため、割れ性ブレークアウトを容
易かつ確実に防止することができる。<Effects of the Invention> As described above, the present invention measures the level of molten metal in the vicinity of the short side of the mold in preventing the cracking breakout that occurs due to cracking immediately below the mold during medium carbonaceous material casting. When the level fluctuation amount exceeds the preset upper limit value, the casting speed is reduced, so that the cracking breakout can be easily and surely prevented.
また、鋳型内溶鋼湯面の変動状況により、鋳型内シェ
ルの不均一凝固発生を予知するため、鋳型上部での検出
により検出器の耐久性の問題を軽減することができる。Further, the occurrence of non-uniform solidification of the shell in the mold is predicted according to the fluctuation state of the molten steel level in the mold, so that the problem of detector durability can be mitigated by detection at the upper part of the mold.
第１図は、この発明に係る方法を実施するための装置を
示す概略図、第２図は連続鋳造設備を示す全体概略図、
第３図は湯面レベル変動による凝固シェル不均一生成を
示す概略断面図、第４図は溶鋼中炭素濃度と短辺割れ性
ブレークアウト発生頻度の関係を示すグラフ、第５図は
湯面レベル変動量と凝固シェル不均一生成度の関係を示
すグラフ、第６図は鋳造速度と短辺割れ性ブレークアウ
ト発生頻度の関係を示すグラフ、第７図は割れ性ブレー
クアウト発生頻度を示すグラフである。 １……取鍋、２……タンディッシュ ３……浸漬ノズル、４……鋳型 4A……鋳型長辺、4B……鋳型短辺 ５……溶鋼、６……案内支持ロール群 6A……駆動ロール ７……湯面検出（渦流）センサー ８……異常検出装置、９……鋳造速度制御装置 10……モニター、11……凝固シェルFIG. 1 is a schematic view showing an apparatus for carrying out the method according to the present invention, and FIG. 2 is an overall schematic view showing a continuous casting facility,
Fig. 3 is a schematic cross-sectional view showing the non-uniform formation of solidified shells due to fluctuations in the molten metal level, Fig. 4 is a graph showing the relationship between the carbon concentration in molten steel and the frequency of short-side cracking breakouts, and Fig. 5 is the molten metal level. FIG. 6 is a graph showing the relationship between the amount of fluctuation and the degree of non-uniform formation of the solidified shell, FIG. 6 is a graph showing the relationship between the casting speed and the short side cracking breakout occurrence frequency, and FIG. 7 is a graph showing the cracking breakout occurrence frequency. is there. 1 ... Ladle, 2 ... Tundish 3 ... Immersion nozzle, 4 ... Mold 4A ... Mold long side, 4B ... Mold short side 5 ... Molten steel, 6 ... Guide support roll group 6A ... Drive Roll 7 …… Melting surface detection (vortex) sensor 8 …… Abnormality detection device, 9 …… Casting speed control device 10 …… Monitor, 11 …… Solidification shell
Claims (1)
凝固に起因して鋳型直下での割れにより発生する割れ性
ブレークアウトの防止方法であって、 鋳型の短辺近傍の湯面レベルを測定し、この鋳型短辺近
傍における局所的な単位時間当たりの湯面レベル変動量
Aiと、予め設定した割れ性ブレークアウト発生を防止で
きる前記湯面レベル変動量の上限値A0とを比較し、Ai＞
A0の場合、鋳造速度を低下させることを特徴とする連続
鋳造の割れ性ブレークアウト防止方法。1. A method for preventing cracking breakout caused by cracking just below the mold due to uneven solidification in the mold in continuous casting of medium carbonaceous material, which is a level of molten metal near the short side of the mold. Is measured, and the amount of local level fluctuations per unit time near the short side of the mold
A i is compared with a preset upper limit value A 0 of the level fluctuation amount that can prevent the occurrence of cracking breakout, and A i >
In the case of A 0, a method for preventing breakable breakout in continuous casting, which is characterized by lowering the casting speed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2267783A JPH0815645B2 (en) | 1990-10-05 | 1990-10-05 | Preventing cracking breakout in continuous casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2267783A JPH0815645B2 (en) | 1990-10-05 | 1990-10-05 | Preventing cracking breakout in continuous casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04143054A JPH04143054A (en) | 1992-05-18 |
| JPH0815645B2 true JPH0815645B2 (en) | 1996-02-21 |
Family
ID=17449525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2267783A Expired - Lifetime JPH0815645B2 (en) | 1990-10-05 | 1990-10-05 | Preventing cracking breakout in continuous casting |
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| Country | Link |
|---|---|
| JP (1) | JPH0815645B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6859919B2 (en) * | 2017-10-18 | 2021-04-14 | 日本製鉄株式会社 | Breakout prediction method |
| JP7726197B2 (en) * | 2022-12-20 | 2025-08-20 | Ｊｆｅスチール株式会社 | Molten steel level control method |
| CN116748483A (en) * | 2023-06-20 | 2023-09-15 | 武汉钢铁有限公司 | A slab continuous casting control method, device, equipment and medium |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5928430B2 (en) * | 1980-01-23 | 1984-07-12 | 川崎製鉄株式会社 | Breakout prevention method in continuous casting |
| JPS6453745A (en) * | 1987-08-24 | 1989-03-01 | Kawasaki Steel Co | Continuous casting method for steel stock of low high temperature strength |
-
1990
- 1990-10-05 JP JP2267783A patent/JPH0815645B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04143054A (en) | 1992-05-18 |
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