JP4254364B2

JP4254364B2 - Thick steel plate controlled rolling apparatus and controlled rolling method using the same

Info

Publication number: JP4254364B2
Application number: JP2003169905A
Authority: JP
Inventors: 健滋井原; 佳徳弓削
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2003-06-13
Filing date: 2003-06-13
Publication date: 2009-04-15
Anticipated expiration: 2023-06-13
Also published as: JP2005000979A

Description

【０００１】
【発明の属する技術分野】
この発明は厚鋼板の制御圧延装置及び厚鋼板の制御圧延方法に係り、特に平坦度の良好な鋼板を製造し得る厚鋼板の制御圧延装置及び厚鋼板の制御圧延方法に関する。
【０００２】
厚鋼板の製造に当たっては、鋼板に要求される機械的性質、特に強度と靭性を確保するため、制御圧延が広く行われている。この制御圧延に当たっては、圧延過程で、圧延機に付帯するミルデスケーラーを利用して、あるいは専用の温度調整冷却装置を利用して圧延過程の鋼板を水冷することが行われる。しかし、圧延機に付帯するミルデスケーラーを利用して圧延過程の鋼板を水冷する場合には、水冷の間、圧延機を開放して通板せざるを得ず、ミルの稼働率が低下するという問題がある。一方、専用の温度調整冷却装置を利用する場合には温度調整冷却後の鋼板の平坦度が劣る場合がある。
【０００３】
このような問題を解決するために、特許文献１には、熱鋼板の表裏面の熱鋼板進行方向に１つ以上の冷却ヘッダーを有し、熱鋼板幅方向に複数のスプレーノズルを有する冷却装置を圧延機の直前および／または直後に配置し、該冷却装置に冷却ヘッダー単位の冷却水制御手段およびスプレーノズル単位のオンオフ制御手段を備えさせ、熱鋼板を冷却しながら複数パス圧延する際、特定の圧延パスにおける冷却スプレー幅を圧延中の鋼板幅以下に設定し、鋼板フロント／テール部の特定範囲のスプレーを遮断する、という発明が開示されている。
【０００４】
また、特許文献２には、厚板圧延ラインの圧延機出側に該圧延ラインと並設した圧延材搬送ラインとの間に、圧延ラインから圧延材搬送ラインへ搬送可能な冷却床と、圧延材搬送ラインから圧延ラインへ搬送可能な冷却床を設け、圧延機の中間厚圧延材を前記冷却床と圧延材搬送ラインで所定の温度に空冷したのち、再度圧延ラインへ戻して所定圧延厚まで圧延する厚鋼板の圧延方法が提案されている。
【０００５】
【特許文献１】
特開平8-57520号公報
【特許文献２】
特開昭60-180604号公報
【０００６】
【発明が解決しようとする課題】
しかし、特許文献１に記載の手段では、鋼板の板内（平面内）温度偏差が小さくなるという利益が得られるものの、鋼板を冷却するためのスプレーノズルが圧延機の直前又は直後に設置されているため、その稼動時には通常の圧延作業が阻害されるとともに、温度調整冷却後に鋼板の平坦度が悪いときに適切な対応策がないという問題がある。一方、特許文献２記載の手段では、冷却床が大掛かりであり、同一の条件で制御圧延を行う場合には好都合であるが、圧延材が小ロットのときにそれぞれに適した冷却条件付与することが難しい。また、特許文献１記載の手段と同様に温度調整冷却後に鋼板の平坦度が悪いときに適切な対応策がないという問題もある。
【０００７】
本発明は、上記従来の制御冷却圧延設備に係る問題点を解決することを目的とし、厚板圧延機の稼働率を低下させることなく、かつ制御冷却時に温度調整冷却の際に発生する鋼板の平坦度の低下を矯正することができる厚鋼板の制御圧延装置及びそれを用いた制御圧延方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明の厚鋼板の制御圧延装置は、厚鋼板の圧延機の後面に温度調整冷却装置、続いて矯正機を設けてなる厚鋼板の制御圧延装置において、前記温度調整冷却装置及び矯正機を開放状態、稼動状態を任意に選択可能なものとするとともに、前記温度調整冷却装置及び矯正機を、中間厚圧延材を圧延機に逆送可能に構成してなる。上記発明において、温度調整冷却装置はその冷却能力が15℃/s（板厚25mm基準）以上とすることが望ましい。また、厚鋼板圧延機と温度調整冷却装置の間には少なくとも20mの間隔を取ることが望ましい。
【０００９】
本発明の目的は、厚鋼板の中間厚圧延材に温度調整冷却を行う厚鋼板の制御圧延において、前記温度調整冷却の前段及び／又は後段において鋼板の矯正工程を行った後、圧延機に逆送して所定圧下率の制御圧延を行うことによって解決できる。
【００１０】
【発明の実施の形態】
図１は、本発明に係る厚鋼板の制御圧延装置の設備レイアウト図である。ここに示すように本発明では、厚板圧延機1の後面側に温度調整冷却装置2、さらにそれに続いて矯正機3が直列に配置される。ミルデスケーラー4は従来どおり圧延機1の圧延材5の噛み込み部に向かって高圧水を噴射するように配置される。
【００１１】
温度調整冷却装置2の構造は、厚板圧延機に付帯して設けられる従来の温度調整冷却装置と特に変わるところはない。ただし、その状態を開放状態、稼動状態が任意に選択可能なものとすることが必要である。また、中間厚圧延材を圧延機に逆送可能に構成することが必要である。その冷却能力は、圧延中の中間厚圧延材に対して十分大きな冷却速度を与えるものであることが必要であり、たとえば、中間厚圧延材の板厚が25mmのとき15℃/s以上の冷却速度を与えるものとするのが望ましい。また、冷却能力を調整できることが望ましい。これにより、短時間で中間厚圧延材の温度を制御圧延に適した温度に調整することができ、厚板の制御圧延工程を被圧延材に応じて適性条件に保ちながら、全体の所要時間を短縮することができる。
【００１２】
矯正機3も厚板の矯正に通常使用されるものを利用することができる。ただし、その状態を開放状態、稼動状態が任意に選択可能なものとすることが必要である。また、中間厚圧延材を圧延機に逆送可能に構成することが必要である。その設置により温度調整冷却装置2の冷却速度を大きくしたとき、中間厚圧延材に平坦度不良が生じても直ちに矯正することができ、円滑に制御圧延を続行できる。
【００１３】
本発明では、このように能力の大きい温度調整冷却装置2と矯正機3をセットして使用する。その際、▲１▼鋼板の矯正工程は温度調整冷却工程の後段に行うことができるほか、まず、▲２▼矯正工程を行なってその後温度調整冷却工程を行なうようにすることもできる。さらに、これらを組み合わせることもできる。
【００１４】
鋼板の矯正工程を温度調整冷却工程の後段に行う場合は、温度調整冷却装置2を水冷状態（稼動状態）にして中間厚圧延材を所定の温度まで冷却し、続いて矯正機3によって所定の平坦度に矯正し（順送状態）、しかる後、矯正機3及び温度調整冷却装置2を開放状態にして圧延機まで逆送により戻して、所定の圧下率により制御圧延を行う。
【００１５】
矯正工程を行なってその後温度調整冷却工程を行なう場合には、温度調整冷却装置2を開放状態にして中間厚圧延材を順送状態で通板し、直ちに矯正機3によって所定の平坦度に矯正し、しかる後、温度調整冷却装置2を水冷状態（稼動状態）にして中間厚圧延材を圧延機側に逆送により戻し、さらに所定の圧下率により制御圧延を行う。この場合、温度調整冷却装置2による水冷を中間厚圧延材の全面にわたって均一に行なえる利益がある。
【００１６】
本発明による厚鋼板の制御圧延装置では、制御圧延の際、中間厚圧延材の強制冷却のためにミルデスケーラーを使用しない。したがって、たとえば普通鋼などを通常の工程により圧延することができる。すなわち、圧延機の後面で制御圧延のための中間厚圧延材に温度調整冷却及び形状矯正を行いながら、圧延機１では通常のとおり、ミルデスケーラー4を稼動しながら普通鋼などの圧延を行い、その製品を一旦、圧延機1の前面に留め置く。この状態で温度調整冷却及び形状矯正を行なった中間厚圧延材を圧延機1に通板して制御圧延を行ない、その完了後、前記圧延機1の前面に留め置かれている普通鋼を後方の冷却設備などに送りこむ。
【００１７】
本発明により、このように圧延機の稼動率を上げることができるが、そのためには、温度調整冷却装置2及び矯正機3の稼動の際、ローラーテーブル上を前後に搬送される中間厚圧延材と、圧延機1の稼動の際、圧延機1の前後面でローラーテーブル上を前後に搬送される普通鋼とが互いに干渉しないことが重要である。そのため、本発明では、圧延機と温度調整冷却装置の間には十分な間隔を、具体的には少なくとも20mの間隔を置くことが望ましい。
【００１８】
本発明にしたがい制御圧延を行う場合と従来法により制御圧延を行う場合の諸操業パラメータを対比して表１に示す。ここに、従来例１とは、温度調整冷却装置のみをもち、矯正機を有しない場合であり、従来例２とは、制御圧延の際、ミルデスケーラーにより中間厚圧延材を水冷するものである。なお、操業は、対象材をすべて板厚10〜70mmの制御圧延材とし、温度調整方法は水冷により１回のみ行なうものとする。水冷はラミナーフロー方式により行い、水量密度は、上部で400l/min・m²、下部で700l/min・m²とした。
【００１９】
【表１】

【００２０】
表１から分かるように、本発明を適用した場合には、ミルアイドルタイムが短く、かつ板内温度偏差が小さく、矯正率が小さく、圧延能率を低下させることなく、平坦度を良好に維持して制御圧延できることが分かる。なお、矯正率とは、製品として出荷する前にオフラインで矯正を行う製品の比率をいう。これに対し、従来例１の場合はミルアイドルタイムが短いが、温度偏差が大きく、従来例２では板内温度偏差は小さいがミルアイドルタイムが長い。
【００２１】
【発明の効果】
本発明により、厚板圧延機の稼働率を低下させることなく、かつ制御冷却時に温度調整冷却の際に発生する鋼板の平坦度の低下を矯正することができる。
【図面の簡単な説明】
【図１】本発明に係る厚鋼板の制御圧延装置の設備レイアウト図である。
【符号の説明】
1：厚板圧延機
2：温度調整冷却装置
3：矯正機
4：ミルデスケーラー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thick steel plate controlled rolling apparatus and a thick steel plate controlled rolling method, and more particularly to a thick steel plate controlled rolling apparatus and a thick steel plate controlled rolling method capable of producing a steel plate with good flatness.
[0002]
In the production of thick steel plates, controlled rolling is widely performed in order to ensure the mechanical properties required for the steel plates, particularly strength and toughness. In this controlled rolling, rolling process, by utilizing the mill de scaler incidental to the rolling mill, or you are utilized to temperature modulated cooling device dedicated to water cooling the steel plate rolling process is performed. However, when the steel sheet in the rolling process is water-cooled using a mill scaler attached to the rolling mill, during the water cooling, the rolling mill must be opened to let it pass, and the operating rate of the mill decreases. There's a problem. On the other hand, when using a dedicated temperature control cooling device, the flatness of the steel plate after temperature control cooling may be inferior.
[0003]
In order to solve such a problem, Patent Document 1 discloses a cooling device having one or more cooling headers in the traveling direction of the hot steel plate on the front and back surfaces of the hot steel plate and a plurality of spray nozzles in the hot steel plate width direction. Is placed immediately before and / or after the rolling mill, and the cooling device is provided with cooling water control means in units of cooling headers and on / off control means in units of spray nozzles. An invention is disclosed in which the cooling spray width in the rolling pass is set to be equal to or less than the width of the steel plate during rolling, and spraying in a specific range of the front / tail portion of the steel plate is blocked.
[0004]
Patent Document 2 discloses a cooling bed that can be transported from the rolling line to the rolling material transport line between the rolling line and the rolling material transport line arranged in parallel on the rolling mill delivery side of the thick plate rolling line, and rolling. A cooling bed that can be conveyed from the material conveying line to the rolling line is provided, and after the intermediate thickness rolled material of the rolling mill is air-cooled to a predetermined temperature in the cooling bed and the rolled material conveying line, it is returned to the rolling line again to the predetermined rolling thickness. A method for rolling thick steel plates to be rolled has been proposed.
[0005]
[Patent Document 1]
JP-A-8-57520 [Patent Document 2]
JP 60-180604 A [0006]
[Problems to be solved by the invention]
However, with the means described in Patent Document 1, the advantage that the temperature deviation within the plate (in plane) of the steel plate is reduced is obtained, but the spray nozzle for cooling the steel plate is installed immediately before or after the rolling mill. Therefore, there are problems that normal rolling work is hindered during operation, and that there is no appropriate countermeasure when the flatness of the steel sheet is poor after temperature-controlled cooling. On the other hand, in the means described in Patent Document 2, the cooling floor is large, which is convenient when controlled rolling is performed under the same conditions. However, when the rolled material is a small lot, it is necessary to provide appropriate cooling conditions for each. Is difficult. In addition, as with the means described in Patent Document 1, there is also a problem that there is no appropriate countermeasure when the flatness of the steel sheet is poor after temperature adjustment cooling.
[0007]
The present invention aims to solve the problems associated with the above-mentioned conventional controlled cooling and rolling equipment, without reducing the operating rate of the thick plate rolling mill, and for the steel sheet generated during temperature-controlled cooling during controlled cooling. An object of the present invention is to provide a controlled rolling apparatus for a thick steel plate capable of correcting a decrease in flatness and a controlled rolling method using the same.
[0008]
[Means for Solving the Problems]
The steel plate control rolling device of the present invention is a steel plate control rolling device in which a temperature control cooling device is provided on the rear surface of the steel plate rolling mill, followed by a straightening device, and the temperature control cooling device and the straightening device are opened. The temperature and cooling device and the straightening machine are configured such that the intermediate thickness rolled material can be fed back to the rolling mill . In the above invention, it is desirable that the temperature adjusting cooling device has a cooling capacity of 15 ° C./s (based on a plate thickness of 25 mm) or more. Further, it is desirable that an interval of at least 20 m be provided between the thick steel plate rolling mill and the temperature control cooling device.
[0009]
An object of the present invention, in the controlled rolling of steel plate to perform the temperature adjustment cooling to the intermediate thickness rolled material of steel plate, after the straightening process of Oite steel in front and / or rear stage of the temperature adjustment cooling, rolling mill It is possible to solve this problem by performing reverse control and performing controlled rolling at a predetermined reduction rate .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an equipment layout diagram of a control rolling device for thick steel plates according to the present invention. As shown here, in the present invention, the temperature adjustment cooling device 2 and further the straightening machine 3 are arranged in series on the rear surface side of the thick plate mill 1. The mill descaler 4 is arranged so as to inject high-pressure water toward the biting portion of the rolling material 5 of the rolling mill 1 as usual.
[0011]
The structure of the temperature control cooling device 2 is not particularly different from that of a conventional temperature control cooling device provided as an accessory to the plate mill. However, it is necessary that the open state and the operating state can be arbitrarily selected. Further, it is necessary to configure the intermediate thickness rolled material so that it can be fed back to the rolling mill. The cooling capacity must provide a sufficiently high cooling rate for the intermediate thickness rolled material during rolling. For example, when the plate thickness of the intermediate thickness rolled material is 25 mm, the cooling capacity is 15 ° C./s or more. It is desirable to give speed. It is desirable that the cooling capacity can be adjusted. As a result, the temperature of the intermediate thick rolled material can be adjusted to a temperature suitable for controlled rolling in a short time, and the overall required time can be reduced while keeping the controlled rolling process of the thick plate at suitable conditions according to the material to be rolled. It can be shortened.
[0012]
The straightening machine 3 can also use the one normally used for straight board correction. However, it is necessary that the open state and the operating state can be arbitrarily selected. Further, it is necessary to configure the intermediate thickness rolled material so that it can be fed back to the rolling mill. When the cooling rate of the temperature adjustment cooling device 2 is increased by the installation, even if the flatness defect occurs in the intermediate thickness rolled material, it can be corrected immediately, and the controlled rolling can be continued smoothly.
[0013]
In the present invention, the temperature adjusting cooling device 2 and the straightening machine 3 having such a large capacity are set and used. At that time, (1) the correction process of the steel sheet can be performed after the temperature adjustment cooling process, or first, the (2) correction process can be performed and then the temperature adjustment cooling process can be performed. Furthermore, these can also be combined.
[0014]
When the steel plate straightening process is performed after the temperature adjustment cooling process, the intermediate temperature rolled material is cooled to a predetermined temperature by setting the temperature adjustment cooling device 2 in a water-cooled state (operating state) , and then a predetermined machine 3 The flatness is corrected (sequentially fed state) , and then the straightening machine 3 and the temperature control cooling device 2 are opened and returned to the rolling mill by reverse feeding , and controlled rolling is performed at a predetermined reduction rate.
[0015]
When the temperature adjustment cooling process is performed after the correction process, the temperature adjustment cooling device 2 is opened and the intermediate thickness rolled material is fed in a progressive state and immediately corrected to a predetermined flatness by the correction machine 3. Thereafter, the temperature adjustment cooling device 2 is set in a water-cooled state (operating state) , and the intermediate-thick rolled material is returned to the rolling mill side by back feeding , and further controlled rolling is performed at a predetermined reduction rate. In this case, there is an advantage that water cooling by the temperature control cooling device 2 can be performed uniformly over the entire surface of the intermediate thickness rolled material.
[0016]
In the controlled rolling apparatus for thick steel plates according to the present invention, a mill descaler is not used for forced cooling of the intermediate thick rolled material during controlled rolling. Therefore, for example, ordinary steel can be rolled by a normal process. That is, while performing temperature adjustment cooling and shape correction on the intermediate thickness rolled material for control rolling on the rear surface of the rolling mill, the rolling mill 1 performs rolling of ordinary steel and the like while operating the mill descaler 4, as usual. The product is temporarily retained on the front surface of the rolling mill 1. In this state, the intermediate thickness rolled material subjected to temperature adjustment cooling and shape correction is passed through the rolling mill 1 to perform controlled rolling, and after the completion, the normal steel retained on the front surface of the rolling mill 1 is moved backward. It is sent to the cooling equipment.
[0017]
According to the present invention, the operation rate of the rolling mill can be increased in this way. For that purpose, when the temperature adjustment cooling device 2 and the straightening machine 3 are operated, the intermediate thickness rolled material conveyed back and forth on the roller table When the rolling mill 1 is in operation, it is important that the front and rear surfaces of the rolling mill 1 do not interfere with each other with the normal steel conveyed back and forth on the roller table. Therefore, in the present invention, it is desirable to provide a sufficient distance between the rolling mill and the temperature control cooling device, specifically, a distance of at least 20 m.
[0018]
Table 1 shows a comparison of various operating parameters when performing controlled rolling according to the present invention and when performing controlled rolling according to the conventional method. Here, Conventional Example 1 is a case where only the temperature adjustment cooling device is provided and no straightening machine is provided, and Conventional Example 2 is a method in which the intermediate thickness rolled material is water-cooled by a mill descaler at the time of controlled rolling. . It should be noted that the operation is carried out with all the target materials being controlled rolled materials having a thickness of 10 to 70 mm, and the temperature adjustment method is performed only once by water cooling. Water cooling was carried out by the laminar flow system, water density is, 400l / min · m ² at the top, and a 700l / min · m ² at the bottom.
[0019]
[Table 1]

[0020]
As can be seen from Table 1, when the present invention is applied, the mill idle time is short, the in-plate temperature deviation is small, the correction rate is small, and the flatness is maintained well without reducing the rolling efficiency. It can be seen that controlled rolling is possible. The correction rate refers to the ratio of products that are corrected off-line before shipping as products. On the other hand, in the case of Conventional Example 1, the mill idle time is short, but the temperature deviation is large. In Conventional Example 2, the in-plate temperature deviation is small, but the mill idle time is long.
[0021]
【The invention's effect】
By this invention, the fall of the flatness of the steel plate which generate | occur | produces in the time of temperature adjustment cooling at the time of control cooling can be corrected, without reducing the operation rate of a thick plate rolling mill.
[Brief description of the drawings]
FIG. 1 is an equipment layout diagram of a control rolling device for thick steel plates according to the present invention.
[Explanation of symbols]
1: Thick plate rolling machine
2: Temperature control cooling device
3: Straightening machine
4: Mildescaler

Claims

In the control rolling device for thick steel plates, which is provided with a temperature adjustment cooling device on the rear surface of the thick steel plate rolling machine, followed by a straightening machine ,
The temperature adjustment cooling device and the straightening machine can be arbitrarily selected from an open state and an operating state, and the temperature adjustment cooling device and the straightening machine are configured so that the intermediate thickness rolled material can be fed back to the rolling mill. controlled rolling apparatus of steel plate, characterized in that.

The controlled rolling apparatus for a thick steel plate according to claim 1, wherein the cooling capacity of the temperature adjusting cooling device is 15 ° C / s or more (based on a thickness of 25 mm).

The controlled rolling apparatus for thick steel plates according to claim 1 or 2, wherein an interval of at least 20 m is placed between the rolling mill and the temperature control cooling device.

In the controlled rolling of thick steel plate that performs temperature-controlled cooling on the intermediate thickness rolled material of thick steel plate,
After the correction process of Oite steel in front and / or rear stage of the temperature adjustment cooling, controlled rolling method of steel plate, characterized in that to perform the controlled rolling of a predetermined pressure under rate backhaul rolling mill.