JPH03277721A - Method for controlling cooling of hot rolled steel strip - Google Patents
Method for controlling cooling of hot rolled steel stripInfo
- Publication number
- JPH03277721A JPH03277721A JP2079195A JP7919590A JPH03277721A JP H03277721 A JPH03277721 A JP H03277721A JP 2079195 A JP2079195 A JP 2079195A JP 7919590 A JP7919590 A JP 7919590A JP H03277721 A JPH03277721 A JP H03277721A
- Authority
- JP
- Japan
- Prior art keywords
- cooling
- hot
- zone
- rolled steel
- temperature
- 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
- 238000001816 cooling Methods 0.000 title claims abstract description 96
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 27
- 239000010959 steel Substances 0.000 title claims abstract description 27
- 238000000034 method Methods 0.000 title claims description 14
- 230000009466 transformation Effects 0.000 claims abstract description 42
- 238000005096 rolling process Methods 0.000 claims abstract description 16
- 238000004804 winding Methods 0.000 claims description 22
- 238000010791 quenching Methods 0.000 claims description 20
- 230000000171 quenching effect Effects 0.000 claims description 20
- 238000005098 hot rolling Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 239000000498 cooling water Substances 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005482 strain hardening Methods 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000029052 metamorphosis Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
- B21B37/76—Cooling control on the run-out table
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Control Of Metal Rolling (AREA)
- Control Of Heat Treatment Processes (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野）
この発明は、熱延鋼帯（ホットコイル）のホットランテ
ーブル上での冷却（ホットラン冷却）方法に係わり、特
にコイル長手方向の特性値変動を抑制して均一な材質を
有するホットコイルを製造するためのホットラン冷却制
御方法に関するものである。[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a method for cooling a hot-rolled steel strip (hot coil) on a hot run table (hot run cooling), and in particular, to a method for cooling a hot rolled steel strip (hot coil) on a hot run table, and in particular to a method for cooling a hot rolled steel strip (hot coil) on a hot run table. The present invention relates to a hot run cooling control method for producing hot coils with uniform material quality.
〈従来技術とその課題〉
一般に、ホットコイルは形状及び材質の均一性を確保し
ながら大量にかつ効率良く製造することが必要とされて
いる。<Prior art and its problems> Generally, hot coils need to be manufactured in large quantities and efficiently while ensuring uniformity in shape and material.
このため、従来より、仕上温度と巻取温度とがコイルの
部位によらず一定となるようにホットラン冷却を制御し
て均質なコイルが得られるように管理することが広く行
われてきた。For this reason, conventionally, it has been widely practiced to control hot run cooling so that the finishing temperature and winding temperature are constant regardless of the location of the coil to obtain a homogeneous coil.
ところが、コイルの部位によらず仕上温度と巻取温度と
を一定に保つことを骨子とした冷却制御方法では圧延速
度も一定に保つ必要が生じ、生産性の面でどうしても制
約を受けざるを得なかった。However, the cooling control method, which is based on keeping the finishing temperature and coiling temperature constant regardless of the part of the coil, requires keeping the rolling speed constant, which inevitably limits productivity. There wasn't.
即ち、近年、ホットコイルの生産性を向上させるべくコ
イルトップ部が巻取機に巻取られた後に圧延速度を増加
させる所謂“加速圧延”が採用されるようになってきた
が、このような加速圧延を行うと、例え仕上温度と巻取
温度とがコイル位置によらず一定となるようにホットラ
ン冷却を制御したとしても仕上圧延機と巻取機との距離
に変化がないため、第２図に示すように、ホットラン冷
却中の冷却速度は一定とはならず、従ってミクロ組織の
変動、ひいては機械的性質の変動を避けることができな
いと言う問題があったためである。That is, in recent years, in order to improve the productivity of hot coils, so-called "accelerated rolling" has been adopted in which the rolling speed is increased after the coil top part is wound on a winder. When accelerated rolling is performed, even if hot run cooling is controlled so that the finishing temperature and winding temperature are constant regardless of the coil position, there is no change in the distance between the finishing mill and the winding machine. As shown in the figure, the cooling rate during hot run cooling is not constant, and therefore there is a problem in that variations in the microstructure and eventually variations in mechanical properties cannot be avoided.
しかし、最近、需要者側におけるホットコイル取り扱い
の自動化が進展するに伴って、従来よりも一段と均一な
特性を有したホットコイルを求める傾向が高まってきて
いる。However, recently, as the automation of hot coil handling on the consumer side progresses, there is an increasing tendency to seek hot coils with more uniform characteristics than before.
そこで、このような要求に応えるべく、例えば特開昭６
２−２５６９２０号にも見られるように、鋼の相変態挙
動をモデル化し、熱間圧延を終えたホットコイルの冷却
を上記モデルに基づいた所定の変態率パターンに沿って
制御しようとする試みも行われている。Therefore, in order to meet such demands, for example,
As seen in No. 2-256920, there have also been attempts to model the phase transformation behavior of steel and to control the cooling of the hot coil after hot rolling according to a predetermined transformation rate pattern based on the above model. It is being done.
しかし、このような相変態挙動予測モデルを用いてのホ
ットコイルの冷却制御法には、オンラインで精密な冷却
速度及び変態速度の計算を行うだけの時間的余裕がなく
て所定パターン通りの冷却が行えないと言う問題があっ
た。つまり、第３図は低炭素鋼をホットラン冷却した時
のホットランテーブル上での変態挙動を材質予測モデル
によって推定した結果であるが、この第３図からも分か
るようにホットコイルの変態は変態開始後２秒程度の時
間内ではり終了しており、実用的な演算器では、このよ
うな短時間に“実測変態率等のブタを基に鋼板各位置に
おける変態速度を一定にするような最適冷却パターンを
割り出す”等の如き複雑な計算を行うことは無理であっ
た。However, in hot coil cooling control methods using such a phase transformation behavior prediction model, there is not enough time to accurately calculate the cooling rate and transformation rate online, making it difficult to cool according to a predetermined pattern. There was a problem that I couldn't do it. In other words, Figure 3 shows the results of estimating the transformation behavior on a hot run table when low carbon steel is cooled in a hot run using a material prediction model. The welding is completed within about 2 seconds, and a practical calculator can calculate the optimal transformation rate at each position of the steel plate based on the measured transformation rate, etc. in such a short time. It was impossible to perform complex calculations such as "determining a cooling pattern."
このようなことから、本発明が目的としたのは、ホント
コイルを製造する際に指摘される前記問題を解消し、長
手方向での特性変動が極めて少ないホ７）コイルを安定
にかつ効率良く製造できる実用的な手段を提供すること
であった。Therefore, the purpose of the present invention is to solve the above-mentioned problems that are pointed out when manufacturing real coils, and to stably and efficiently manufacture coils with very little variation in characteristics in the longitudinal direction. The aim was to provide a practical means of manufacturing.
く課題を解決するための手段〉
本発明者は、上記目的を達成すべく様々な観点に立って
研究を重ねた結果、次に示すような思考過程を経て後述
するような新しい知見を得ることができた。Means for Solving the Problem> As a result of repeated research from various viewpoints in order to achieve the above object, the inventor has obtained new knowledge as described below through the following thought process. was completed.
即ち、先にも述べたように、ホットコイルを仕上圧延し
た後でホットラン冷却するに際し、仕上温度と巻取温度
を一定に保つような冷却制御を行ったとしても部分的な
特性不均一を生じる原因は、主として冷却速度の変動に
あり、冷却速度の変動を小さくするように冷却制御を行
えばミクロ組織の変動が抑えられ、その結果としてコイ
ル長手方向における特性の均一化が図れることが推察さ
れる。つまり、第４図は材質予測モデルで予測した低炭
素鋼の連続冷却変態線図であり、冷却速度が変動（図中
の番号■〜■はそれぞれ異なる冷却速度曲線である）す
ると“変態生成相の体積率”や“フェライト、パーライ
ト等の生成温度”も変動することを示しているが、この
事実は、逆に冷却速度の変動を無くすることがコイル長
手方向における特性の均一化に有効であることを示して
いるとも言える。In other words, as mentioned earlier, when a hot coil is subjected to hot run cooling after finishing rolling, even if cooling control is performed to keep the finishing temperature and coiling temperature constant, local property non-uniformity occurs. The cause is mainly due to fluctuations in the cooling rate, and it is assumed that if cooling control is performed to reduce fluctuations in the cooling rate, fluctuations in the microstructure can be suppressed, and as a result, the characteristics in the longitudinal direction of the coil can be made uniform. Ru. In other words, Fig. 4 is a continuous cooling transformation diagram of low carbon steel predicted by the material prediction model, and when the cooling rate fluctuates (numbers ■ to ■ in the figure are different cooling rate curves), the “transformation formation phase This shows that the "volume fraction of ferrite, pearlite, etc." and the "formation temperature of ferrite, pearlite, etc." also fluctuate, but this fact suggests that eliminating fluctuations in the cooling rate is effective in making the characteristics uniform in the longitudinal direction of the coil. It can also be said that this indicates something.
しかしながら、このような施策は実際上冷却速度の変動
を避けがたい加速圧延が導入されているホットコイル製
造ラインでは採用することができない上、“冷却速度の
変動”はどではないにしても“圧延仕上温度の変動”等
も少なからずホットコイル長手方向での特性不均一に影
響を及ぼす要因となっている。なお、第５図はやはり材
質予測モデルで予測した低炭素鋼の加工連続冷却変態線
図であり、これによって加工硬化したオーステナイトの
相変態挙動を推定できると考えられる・が、この第５図
からも、仕上温度が変動してオーステナイトの加工硬化
の程度が変動すると変態曲線自体が大きく変化するため
、ミクロ組織の変動を避けられないことが窺える。However, such measures cannot be adopted in hot coil production lines where accelerated rolling is introduced, where variation in cooling rate is unavoidable. Fluctuations in rolling finishing temperature are also factors that affect the non-uniformity of properties in the longitudinal direction of hot coils. Furthermore, Figure 5 is a continuous cooling transformation diagram for low carbon steel predicted by the material prediction model, and it is thought that the phase transformation behavior of work-hardened austenite can be estimated from this diagram. However, if the finishing temperature changes and the degree of work hardening of austenite changes, the transformation curve itself changes significantly, so it can be seen that changes in the microstructure cannot be avoided.
このように、連続冷却中の変態挙動は種々の要因により
大きく変化するため、均質なホットコイルを得るには、
結局はこれらの要因の影響を全て精度良く予測して冷却
制御を行うか、或いはオンラインでの変態率等の実測デ
ータを基にフィードバック或いはフィードフォワード制
御を行うことが必要となるが、前者に関しては未だ十分
な予測精度が得られていないし、後者については演算時
間の制約があって実用できない等の問題がある。In this way, the transformation behavior during continuous cooling changes greatly due to various factors, so in order to obtain a homogeneous hot coil,
In the end, it is necessary to perform cooling control by accurately predicting the effects of all of these factors, or to perform feedback or feedforward control based on online measured data such as transformation rate, but regarding the former, Sufficient prediction accuracy has not yet been obtained, and the latter has problems such as being impractical due to calculation time constraints.
しかるに、本発明者は、「冷却速度やオーステナイトの
加工硬化程度等に影響される相変態を等温の状態で進行
させてやればその変態温度に応じた一定の変態組織が得
られ、上述したような問題点を回避できる筈である」と
の考えの下に、種々の炭素綱を用い、仕上圧延後に種々
の急冷停止温度Ｔｌ１１まで急速冷却してから等温変態
になぞらえた空冷を施す実験を行った後、得られた鋼板
の機械的性質を調査し、「仕上圧延後所定の温度まで急
速冷却した後空冷によっては一゛等温の状態で変態を完
了させると、仕上温度の変動或いは加速圧延による通板
速度の変化によらず一定のミクロ組織を有するホットコ
イルが得られる」との知見を得たのである。However, the inventor believes that ``If the phase transformation, which is influenced by the cooling rate and the degree of work hardening of austenite, is allowed to proceed in an isothermal state, a constant transformed structure corresponding to the transformation temperature can be obtained, and as mentioned above, Based on this idea, we conducted experiments in which various carbon steels were rapidly cooled to various quenching stop temperatures T11 after finishing rolling, and then air-cooled in a manner similar to isothermal transformation. After that, the mechanical properties of the obtained steel sheet were investigated. They found that a hot coil with a constant microstructure can be obtained regardless of changes in the threading speed.
例えば、第６図はＦｅ−０，１４ｗｔ％Ｃ−０，０３ｉ
ｍｔ％Ｓｉ１ 、３４ｗ ｔ％Ｍｎ綱についての調査結
果である。この第６図からも、鋼板の硬さは急冷停止温
度Ｔｒｒｌの低下に伴い増加するが、急冷停止温度Ｔｍ
かは＼一定であればオーステナイトの状態によらずは＼
一定の硬さ（ミクロ組織）となることが明らかである。For example, Fig. 6 shows Fe-0,14wt%C-0,03i
These are the investigation results for mt%Si1, 34wt%Mn class. This figure 6 also shows that the hardness of the steel plate increases as the quenching stop temperature Trrl decreases, but the hardness of the steel plate increases as the quenching stop temperature Trrl decreases.
If it is constant, it does not depend on the state of austenite.
It is clear that the hardness (microstructure) is constant.
なお、急冷停止温度Ｔｍと硬さとの関係は鋼種によって
変化するが、何れの場合も急冷停止温度Ｔ＋ｍが一定で
あればはり一定の硬さが得られた。Although the relationship between the quenching stop temperature Tm and the hardness varies depending on the steel type, in any case, if the quenching stop temperature T+m was constant, a constant hardness was obtained.
ただ、この場合でも、巻取温度は変態生成相の析出・軟
化挙動に影響を及ぼすので一定にする必要があるが、変
態途中に冷却制御を行うと変態潜熱等の影響を考慮しな
がら鋼板の温度を計算することが必要となり、所定の温
度で精度良く巻取ることが困難となる。しかし、空冷ゾ
ーンに変態率計等を設置し、この変態率計により変態の
完了を確認した後、空冷ゾーンと制御冷却ゾーンの間に
設置した巻取制御温度計の実測温度に基づいて制御冷却
ゾーンにおける冷却水量を制御すれば、精度良い巻取温
度制御が可能となって上記問題は払拭される。However, even in this case, the coiling temperature must be kept constant as it affects the precipitation and softening behavior of the phase formed during transformation. It is necessary to calculate the temperature, which makes it difficult to accurately wind the film at a predetermined temperature. However, a transformation rate meter, etc. is installed in the air cooling zone, and after confirming the completion of transformation with this transformation rate meter, control cooling is performed based on the actual temperature measured by a winding control thermometer installed between the air cooling zone and the control cooling zone. By controlling the amount of cooling water in the zone, it becomes possible to control the winding temperature with high precision, and the above-mentioned problem can be eliminated.
本発明は、上記幾つかの知見事項等を基にして完成され
たものであり、
［熱間圧延終了後の熱延鋼帯をホットランテーブル上で
冷却し巻取るに際して、ホットランテブルを仕上圧延機
側から急冷ゾーン、空冷ゾーン及び制御冷却ゾーンの３
区分に分割しておくと共に、まず急冷ゾーンにて予め定
めた急冷停止温度にまで急速冷却し、続いて空冷ゾーン
において変態が完了するまで空冷した後、引き続き制御
冷却ゾーンにて所定の巻取温度となるように制御冷却し
てから巻取ることにより、長平方向の特性が非常に均一
なホットコイルを安定して製造し得るようにした点」
そ特徴とするものである。The present invention was completed based on the above-mentioned several findings. From the side: quenching zone, air cooling zone, and control cooling zone.
In addition to dividing it into sections, it is first rapidly cooled in the quenching zone to a predetermined quenching stop temperature, then air cooled in the air cooling zone until the transformation is completed, and then continued to the controlled cooling zone to a predetermined winding temperature. By controlling the cooling so that the coil is cooled and then winding it, it is possible to stably manufacture hot coils with extremely uniform properties in the longitudinal direction.
く作用・効果〉
上述のように、本発明では、ホットコイルのホットラン
冷却に際し、仕上圧延後のホットコイルを所定の急冷停
止温度Ｔｍまで急冷して所望の特性（強度等）が得られ
るようにした後、空冷によっては一゛等温状態で安定し
た変態を完了させ、続いて巻取制御温度Ｔｃの実測値に
基づいて所定の巻取温度まで制御冷却して巻取るので、
加速圧延等のように通板速度がコイル長手方向で変動す
るような場合でも、或いは仕上温度の変動によりオース
テナイトの加工硬化の程度がコイル長手方向で変動する
ようなことがあっても一定の温度で変態を進行させるこ
とができ、しかも巻取温度をも精度良く一定に保つこと
ができるので、コイル長手方向のミクロ組織の変化が小
さい、極めて均一な特性を有するホットコイルの製造が
可能となる。Functions and Effects> As described above, in the present invention, during hot run cooling of a hot coil, the hot coil after finish rolling is rapidly cooled to a predetermined quenching stop temperature Tm so that desired properties (strength, etc.) can be obtained. After that, stable transformation is completed in an isothermal state by air cooling, and then controlled cooling is performed to a predetermined winding temperature based on the actual value of the winding control temperature Tc, and the winding is performed.
Even if the threading speed varies in the longitudinal direction of the coil, such as during accelerated rolling, or the degree of work hardening of austenite varies in the longitudinal direction of the coil due to variations in finishing temperature, the temperature remains constant. Since the transformation can proceed with the coil and the coiling temperature can be kept constant with high precision, it is possible to manufacture hot coils with very uniform characteristics and minimal changes in the microstructure in the longitudinal direction of the coil. .
また、本発明においては変態開始以前に急速冷却し、か
つ変態完了後にも制御冷却するので、変態速度と冷却速
度によって複雑に変化する変態潜熱の影響を考慮する必
要もなく、しかも鋼板の物性値（例えば比熱や密度）に
関してもオーステナイト又はフェライト単相についての
み考えれば良いことから、温度制御の精度も向上する。In addition, in the present invention, rapid cooling is performed before the start of transformation, and controlled cooling is performed even after the completion of transformation, so there is no need to consider the influence of latent heat of transformation, which changes complicatedly depending on the transformation rate and cooling rate, and the physical properties of the steel sheet Regarding (for example, specific heat and density), since it is only necessary to consider the austenite or ferrite single phase, the accuracy of temperature control is also improved.
更に、必要な計算も“綱板温度の推定”に関するものの
みであるので短時間で行うことができ、そのためオンラ
インでのダイナミックな冷却制御が可能となって精度の
大幅な向上にもつながる。Furthermore, since the required calculations are only related to estimating the steel plate temperature, they can be performed in a short time, making it possible to perform online dynamic cooling control, leading to a significant improvement in accuracy.
なお、前記「急冷停止温度ＴｍＪは鋼板の化学成分や必
要強度等に応じて設定されるが、その設定には、例えば
実験にて特定成分鋼に関する「強度−急冷停止温度Ｔｌ
１１曲線（第６図のような曲線）」を求めて置く方法や
、所定特性を得るための実験式に基づいて算出する方法
等を採用すれば良い。The above-mentioned "quenching stop temperature TmJ" is set according to the chemical composition and required strength of the steel plate, but for example, the "strength - quenching stop temperature Tl
11 curve (such as the curve shown in FIG. 6), or a method of calculating based on an empirical formula for obtaining a predetermined characteristic, etc. may be adopted.
続いて、本発明を実施例によって更に具体的に説明する
。Next, the present invention will be explained in more detail with reference to Examples.
〈実施例〉
この実施例では、第１図に示すようなホットラン冷却設
備を用いて仕上圧延後のホットコイルの冷却及び巻取り
を行った。<Example> In this example, a hot run cooling equipment as shown in FIG. 1 was used to cool and wind up a hot coil after finish rolling.
即ち、第１図で示す冷却設備は仕上圧延機（１）で圧延
された鋼板（２）を急冷ゾーン（３）で所定の急冷停止
温度Ｔｌ１１まで急速冷却した後、空冷ゾーン（４）で
空冷し、その後更に制御冷却ゾーン（５）で制御冷却し
てから巻取機（６）で巻取ってホットコイルとするもの
であるが、この実施例では、仕上圧延機（１１の直後に
配置した温度計（７］によって実測された仕上温度と通
板速度計（８）によって実測された鋼板移動速度等のデ
ータを冷却制御用マイコンαりにフィードフォワードさ
せると共に、予め入力されている鋼板の板厚や材質等の
データをも加味して必要な冷却水量等を算出し、冷却バ
ンク制御装置αつに指示を与えるようにした。また、急
冷ゾーン（３）直後には水切り装置（９）と変態制御用
温度計０ｒｆＩが設置されており、水切り装置（９）で
鋼板表面の冷却水を除去した後に変態制御用温度計００
で実測された温度は冷却制御用マイコンα船にフィード
バックされ、急冷ゾーン（３）での冷却制御のｍｆｌ整
に利用される。That is, the cooling equipment shown in Fig. 1 rapidly cools a steel plate (2) rolled by a finishing mill (1) in a quenching zone (3) to a predetermined quenching stop temperature Tl11, and then cools it with air in an air cooling zone (4). After that, it is further controlled and cooled in a controlled cooling zone (5) and then wound up in a winder (6) to form a hot coil. Data such as the finishing temperature actually measured by the thermometer (7) and the steel plate movement speed actually measured by the plate threading speed meter (8) are fed forward to the cooling control microcomputer α, and the data of the steel plate that has been input in advance is fed forward. The required amount of cooling water is calculated by taking into consideration data such as thickness and material, and instructions are given to the cooling bank control device α.Also, immediately after the quenching zone (3), a draining device (9) is installed. A transformation control thermometer 0rfI is installed, and the transformation control thermometer 0rfI is installed after the cooling water on the surface of the steel plate is removed by the drainer (9).
The temperature actually measured is fed back to the cooling control microcomputer α ship and used to adjust the mfl of the cooling control in the rapid cooling zone (3).
次に、空冷ゾーン（４）の中には１台以上の変態重訂α
υが設置されており、実測した変態率を冷却制御用マイ
コン０４）にフィードフォワードして空冷ゾーン（４）
で変態が完了することを確認する。もし、仮に変態が完
了しない場合には急冷ゾーン（３）の冷却を強化して変
態制御用温度計測で実測される急冷停止温度Ｔｍを低下
させ、空冷ゾーン（４）での変態を促進させる。更に、
空冷ゾーン（４）の直後に配置された巻取制御用温度計
（財）で実測された温度は冷却制御用マイコンａ０にフ
ィードフォワードされ、通板速度、板厚、材質等のデー
タと共に必要な冷却水量等の算出が行われた後、これに
基づいた冷却バンク制御装置αりへの指示がなされ、制
御冷却シン（５）の冷却が制御される。そして、巻取機
（６）の直前には巻取温度計α濁が配置されているが、
この巻取温度計■で実測された巻取温度は冷却制御用マ
イコンＱ４１にフィードバックされ、制御冷却ゾーン（
５）での冷却の微調整に利用される。Next, in the air cooling zone (4) there is one or more transformation
υ is installed, and the actually measured transformation rate is fed forward to the cooling control microcomputer 04) and the air cooling zone (4)
to confirm that the metamorphosis is complete. If the transformation is not completed, the cooling in the quenching zone (3) is strengthened to lower the quenching stop temperature Tm actually measured by temperature measurement for transformation control, and the transformation in the air-cooling zone (4) is promoted. Furthermore,
The temperature actually measured by the winding control thermometer placed immediately after the air cooling zone (4) is fed forward to the cooling control microcomputer a0, which records the necessary data such as sheet threading speed, sheet thickness, material, etc. After calculating the amount of cooling water, etc., an instruction is given to the cooling bank control device α based on the calculation, and cooling of the control cooling sink (5) is controlled. A winding thermometer α is placed just before the winder (6).
The winding temperature actually measured by this winding thermometer ■ is fed back to the cooling control microcomputer Q41, and the control cooling zone (
It is used for fine adjustment of cooling in step 5).
第７図は、上記の如き本発明による冷却制御を実施した
場合（本発明例）と従来通り仕上温度と巻取温度の制御
のみを実施した場合（比較例）との鋼板長手方向の機械
的性質を調査した結果を比較したものである。なお、適
用した鋼種は５５キロ鋼（Ｆｅ−０，１４ｗｔχＣ−０
，０３ｗｔχ５ｉ−１，３０ｗｔχＭｎ）で、これを板
厚：３．２ｍに仕上圧延した後ホットラン冷却し、５０
０℃で巻取った。ここで、本発明例では仕上圧延後のホ
ントコイルを直ちに６２０℃まで水冷し、続いて該温度
から空冷して変態を完了させてから巻取温度まで制御冷
却した後巻取った。Figure 7 shows the mechanical properties of the steel sheet in the longitudinal direction when the cooling control according to the present invention as described above is implemented (invention example) and when only the finishing temperature and coiling temperature are controlled as before (comparative example). This is a comparison of the results of investigating the properties. The applied steel type was 55kg steel (Fe-0, 14wtχC-0
, 03wtχ5i-1, 30wtχMn), this was finish rolled to a plate thickness of 3.2m, hot-run cooled, and
It was wound up at 0°C. Here, in the example of the present invention, the real coil after finishing rolling was immediately water-cooled to 620°C, then air-cooled from this temperature to complete the transformation, and then controlled to be cooled to the coiling temperature and then coiled.
この第７図からも明らかなように、本発明方法によれば
通板速度、圧延仕上温度の変動によらず機械低性質の変
動を安定して抑制することができ、コイル長手方向の特
性の均一化に大いに役立つことが分かる。As is clear from FIG. 7, according to the method of the present invention, fluctuations in mechanical properties can be stably suppressed regardless of fluctuations in strip threading speed and finishing temperature, and changes in properties in the longitudinal direction of the coil can be suppressed. It can be seen that this is very useful for uniformity.
また、本発明方法による冷却制御を実施した場合の“巻
取温度の的中率”は９６％程度であり、従来通り仕上温
度と巻取温度の制御のみを実施した場合の巻取温度の的
中率−８７％よりも大幅に向上することも確認された。In addition, the "accuracy rate of winding temperature" when implementing the cooling control according to the method of the present invention is about 96%, compared to the conventional method of controlling only the finishing temperature and winding temperature. It was also confirmed that the medium rate was significantly improved from -87%.
従って、本発明方法によると、巻取温度の変動を抑制す
ることも容易となり、特性の均一化効果を安定させる上
で極めて有利である。Therefore, according to the method of the present invention, fluctuations in the winding temperature can be easily suppressed, which is extremely advantageous in stabilizing the effect of uniformizing characteristics.
〈効果の総括〉
以上に説明した如く、この発明によれば、通板速度、圧
延仕上温度が変動しても、長平方向のミクロ組織、特性
値の変動が極めて小さい均質なホットコイルを生産性良
く安定製造することが可能となるなど、産業上極めて有
用な効果がもたらされる。<Summary of Effects> As explained above, according to the present invention, even if the threading speed and rolling finish temperature vary, a homogeneous hot coil with extremely small fluctuations in the longitudinal microstructure and characteristic values can be produced with high productivity. This brings about extremely useful effects industrially, such as making it possible to produce products in a stable manner.
第１図は、実施例で使用した本発明性実施に係わるホッ
トラン冷却設備の構成を示す概略説明図である。
第２図は、ホットランテーブルでの通板速度の変化に伴
う鋼板の冷却速度変化を示した概念図である。
第３図は、低炭素鋼をホットラン冷却した時のホットラ
ンテーブル上での変態率の推移を示したグラフである。
第４図は、低炭素鋼の連続冷却変態線図である。
第５図は、低炭素鋼の加工連続冷却変態線図である。
第６図は、急冷停止温度Ｔｍと硬さのとの関係を示すグ
ラフである。
第７図は、“本発明方法例を実施したホットコイルにお
ける長平方向の機械的性質”を従来例のそれと比較した
グラフである。
図面において、
１・・・仕上圧延機、 ２・・・鋼板。
３・・・急冷ゾーン、 ４・・・空冷ゾーン。
５・・・制御冷却ゾーン、６・・・巻取機。
８・・・通板速度計
１０・・・変態制御用温度計。
１２・・・巻取制御用温度計。
７・・・仕上温度計。
９・・・水切り装置。
１１・・・変態率針。
１３・・・巻取温度計。
１４・・・冷却制御用マイコン
１５・・・冷却バンク制御装置。FIG. 1 is a schematic explanatory diagram showing the configuration of a hot run cooling facility according to the embodiment of the present invention used in Examples. FIG. 2 is a conceptual diagram showing changes in the cooling rate of a steel plate due to changes in the passing rate on the hot run table. FIG. 3 is a graph showing the change in transformation rate on a hot run table when low carbon steel is cooled in a hot run. FIG. 4 is a continuous cooling transformation diagram of low carbon steel. FIG. 5 is a continuous cooling transformation diagram of low carbon steel. FIG. 6 is a graph showing the relationship between quenching stop temperature Tm and hardness. FIG. 7 is a graph comparing the "mechanical properties in the longitudinal direction of the hot coil in which the method example of the present invention was implemented" with that of the conventional example. In the drawings: 1... Finishing rolling mill, 2... Steel plate. 3...Quick cooling zone, 4...Air cooling zone. 5... Control cooling zone, 6... Winding machine. 8... Sheet threading speed meter 10... Thermometer for transformation control. 12...Thermometer for winding control. 7... Finishing thermometer. 9...Draining device. 11... Perversion rate needle. 13... Winding thermometer. 14... Cooling control microcomputer 15... Cooling bank control device.
Claims (1)
却し巻取るに際して、ホットランテーブルを仕上圧延機
側から急冷ゾーン、空冷ゾーン及び制御冷却ゾーンの３
区分に分割しておくと共に、まず急冷ゾーンにて予め定
めた急冷停止温度にまで急速冷却し、続いて空冷ゾーン
において変態が完了するまで空冷した後、引き続き制御
冷却ゾーンにて所定の巻取温度となるように制御冷却し
てから巻取ることを特徴とする、熱延鋼帯の冷却制御方
法。When the hot-rolled steel strip after hot rolling is cooled and wound on the hot run table, the hot run table is divided into three zones from the finish rolling mill side: a quenching zone, an air cooling zone, and a controlled cooling zone.
In addition to dividing it into sections, it is first rapidly cooled in the quenching zone to a predetermined quenching stop temperature, then air cooled in the air cooling zone until the transformation is completed, and then continued to the controlled cooling zone to a predetermined winding temperature. A method for controlling the cooling of a hot rolled steel strip, the method comprising controlling the cooling so that the temperature becomes as follows, and then winding the strip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2079195A JPH03277721A (en) | 1990-03-28 | 1990-03-28 | Method for controlling cooling of hot rolled steel strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2079195A JPH03277721A (en) | 1990-03-28 | 1990-03-28 | Method for controlling cooling of hot rolled steel strip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03277721A true JPH03277721A (en) | 1991-12-09 |
Family
ID=13683195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2079195A Pending JPH03277721A (en) | 1990-03-28 | 1990-03-28 | Method for controlling cooling of hot rolled steel strip |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03277721A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001017704A1 (en) * | 1999-09-10 | 2001-03-15 | Siemens Aktiengesellschaft | Method and device for cooling a hot rolled steel strip that runs off a roll stand |
| JP2002361312A (en) * | 2001-06-13 | 2002-12-17 | Kawasaki Steel Corp | Method for cooling thick and high tensile strength hot rolled steel strip |
| KR101008131B1 (en) * | 2008-06-27 | 2011-01-13 | 주식회사 포스코 | Hot rolled coil cooling system, slow cooling apparatus and slow cooling method in the hot rolled coil cooling system |
| US8359894B2 (en) | 2009-12-16 | 2013-01-29 | Nippon Steel Corporation | Method for cooling hot-rolled steel strip |
| JP2014065077A (en) * | 2012-09-06 | 2014-04-17 | Jfe Steel Corp | Method of manufacturing hot rolled steel plate |
| CN104070075A (en) * | 2014-06-04 | 2014-10-01 | 北京中冶设备研究设计总院有限公司 | Laminar cooling process control device and method for hot rolled strip steel |
| CN104307891A (en) * | 2014-11-07 | 2015-01-28 | 武汉钢铁(集团)公司 | Stepped hot rolled strip production line laminar flow cooling control method |
-
1990
- 1990-03-28 JP JP2079195A patent/JPH03277721A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001017704A1 (en) * | 1999-09-10 | 2001-03-15 | Siemens Aktiengesellschaft | Method and device for cooling a hot rolled steel strip that runs off a roll stand |
| JP2002361312A (en) * | 2001-06-13 | 2002-12-17 | Kawasaki Steel Corp | Method for cooling thick and high tensile strength hot rolled steel strip |
| JP4677685B2 (en) * | 2001-06-13 | 2011-04-27 | Ｊｆｅスチール株式会社 | Cooling method for thick-walled high-tensile hot-rolled steel strip |
| KR101008131B1 (en) * | 2008-06-27 | 2011-01-13 | 주식회사 포스코 | Hot rolled coil cooling system, slow cooling apparatus and slow cooling method in the hot rolled coil cooling system |
| US8359894B2 (en) | 2009-12-16 | 2013-01-29 | Nippon Steel Corporation | Method for cooling hot-rolled steel strip |
| JP2014065077A (en) * | 2012-09-06 | 2014-04-17 | Jfe Steel Corp | Method of manufacturing hot rolled steel plate |
| CN104070075A (en) * | 2014-06-04 | 2014-10-01 | 北京中冶设备研究设计总院有限公司 | Laminar cooling process control device and method for hot rolled strip steel |
| CN104307891A (en) * | 2014-11-07 | 2015-01-28 | 武汉钢铁(集团)公司 | Stepped hot rolled strip production line laminar flow cooling control method |
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