JP2774030B2 - Steel sheet cooling method - Google Patents
Steel sheet cooling methodInfo
- Publication number
- JP2774030B2 JP2774030B2 JP4339069A JP33906992A JP2774030B2 JP 2774030 B2 JP2774030 B2 JP 2774030B2 JP 4339069 A JP4339069 A JP 4339069A JP 33906992 A JP33906992 A JP 33906992A JP 2774030 B2 JP2774030 B2 JP 2774030B2
- Authority
- JP
- Japan
- Prior art keywords
- cooling
- steel sheet
- temperature
- longitudinal direction
- water
- 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.)
- Expired - Fee Related
Links
Landscapes
- Control Of Metal Rolling (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、厚鋼板などの水冷にお
いて長手方向に均一に冷却する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for uniformly cooling a steel plate or the like in a longitudinal direction by water cooling.
【０００２】[0002]
【従来の技術】一般に厚板製造工程において、焼き入れ
を目的とした冷却や、さらには合金元素の低減、省熱処
理などを目的とした圧延直後の制御冷却では水を冷媒と
した冷却プロセスが採用されている。そして制御冷却で
は、この冷却を途中の常温よりかなり高い温度で停止す
る技術が良く用いられるようになった。このプロセスに
おいて冷却装置内を通板させながら鋼板の先端から順次
冷却していく方法（以下通板冷却という）では、鋼板長
手方向各位置における冷却開始時刻に差が生じるため、
鋼板長手方向の各位置における冷却開始温度に差が生
じ、一定速度で通板した場合鋼板長手方向の位置により
冷却停止温度に偏差が発生する。2. Description of the Related Art Generally, a cooling process using water as a cooling medium is employed in a cooling process for quenching and in a controlled cooling process immediately after rolling for the purpose of reducing alloy elements and saving heat treatment in a thick plate manufacturing process. Have been. In the controlled cooling, a technique of stopping the cooling at a temperature considerably higher than the normal temperature on the way has come to be used frequently. In this process, in the method of sequentially cooling from the tip of the steel sheet while passing through the cooling device (hereinafter referred to as “passing cooling”), there is a difference in the cooling start time at each position in the longitudinal direction of the steel sheet,
A difference occurs in the cooling start temperature at each position in the longitudinal direction of the steel sheet, and when the sheet is passed at a constant speed, a deviation occurs in the cooling stop temperature depending on the position in the longitudinal direction of the steel sheet.
【０００３】この他、圧延前のスラブの加熱状態や、圧
延中のデスケーリングの影響など、前記以外の要因によ
る圧延終了時（または冷却開始時）の長手方向の温度差
が冷却停止温度偏差となって発生している。鋼板長手方
向の冷却停止温度を均一にすることは鋼板の残留応力発
生防止や、長手方向にわたり均一な材質を得るために重
要である。この問題に対し、特開昭61-213327 号公報、
特開昭61-253112 号公報、特開昭62-199723 号公報およ
び特開平2-179826号公報では、冷却装置入り側で鋼板長
手方向の各位置における温度を検出してその結果に応じ
て鋼板の通板速度を調整し、長手方向の冷却停止温度が
均一になるようないくつかの提案がなされている。[0003] In addition, the temperature difference in the longitudinal direction at the end of rolling (or at the start of cooling) due to factors other than the above, such as the heating state of the slab before rolling and the effect of descaling during rolling, is the difference between the cooling stop temperature deviation and the cooling stop temperature deviation. Has occurred. It is important to make the cooling stop temperature uniform in the longitudinal direction of the steel sheet in order to prevent generation of residual stress in the steel sheet and to obtain a uniform material in the longitudinal direction. To solve this problem, Japanese Patent Laid-Open No. 61-213327,
In JP-A-61-253112, JP-A-62-199723 and JP-A-2-179826, the temperature at each position in the longitudinal direction of the steel sheet is detected on the cooling device entrance side, and the steel sheet is detected in accordance with the result. Some proposals have been made to adjust the passing speed of the steel sheet so that the cooling stop temperature in the longitudinal direction becomes uniform.
【０００４】しかしこれらの従来技術はそのほぼすべて
が鋼板上下からのスプレー状あるいは柱状の水による冷
却、すなわち冷却水の冷却能力はつねにコンスタントな
状態で冷却を制御する方法であり、スプレー状あるいは
柱状の水は常に新しい水と入れ替わっており、本発明の
対象であるドブ漬けのように鋼板周辺に水が滞留するこ
とにより冷却中に冷却能力が低下するようなことはな
い。However, almost all of these prior arts are cooling by spraying or columnar water from above and below the steel plate, that is, a method of controlling the cooling in a state where the cooling capacity of the cooling water is always constant. This water is always replaced with fresh water, and the cooling capacity does not decrease during cooling due to the water remaining around the steel plate as in the case of pickling, which is the subject of the present invention.
【０００５】[0005]
【発明が解決しようとする課題】前述した従来技術は、
冷却開始時の鋼板長手方向温度差に対して冷却停止時の
鋼板長手方向温度を均一にする方法であった。これは供
給する水量密度が最大100l/m2min程度までの水冷設備
で、供給した水が、比較的早く入れ替わる。すなわちつ
ねに新しい水が鋼板表面を冷却できる状態にあり、冷却
装置の冷却能力が鋼板冷却中にほとんど変化しない場合
に適用できる方法である。しかしさらに高い冷却能を得
るために水量密度を大きくした場合、鋼板の冷却は浸漬
状態となり、冷却装置内の冷却メカニズムは水量密度が
少ない場合と異なってくる。The prior art described above is
In this method, the temperature in the longitudinal direction of the steel sheet when cooling was stopped was made uniform with respect to the temperature difference in the longitudinal direction of the steel sheet when cooling started. This is a water cooling system with a supplied water density of up to about 100 l / m 2 min. The supplied water is replaced relatively quickly. That is, this method is applicable when fresh water is always in a state capable of cooling the steel sheet surface and the cooling capacity of the cooling device hardly changes during the cooling of the steel sheet. However, when the water density is increased in order to obtain a higher cooling capacity, the cooling of the steel sheet is immersed, and the cooling mechanism in the cooling device is different from that when the water density is low.
【０００６】浸漬状態での冷却では鋼板の先端はつねに
入れ替わった新しい水で冷却されるのに対し、鋼板の尾
端は、十分に入れ替えされていない温度の上昇した水で
冷却される。初期の温度の低い水による冷却と後期の温
度の上昇した水では冷却能に差があるため、鋼板を一定
の速度で通板した場合、鋼板先端では冷却停止温度が低
く、尾端では冷却停止温度が高くなる現象が発生すると
いう問題がある。[0006] In the cooling in the immersion state, the tip of the steel sheet is cooled by fresh water that is constantly replaced, while the tail end of the steel sheet is cooled by water that has not been sufficiently replaced and has an increased temperature. Since there is a difference in cooling capacity between cooling with low-temperature water at the initial stage and water with a higher temperature in the latter period, when the steel sheet is passed at a constant speed, the cooling stop temperature is low at the tip of the steel sheet and stopped at the tail end. There is a problem that a phenomenon that the temperature becomes high occurs.
【０００７】本発明では、上記問題を解決した浸漬型冷
却における鋼板長手方向の均一冷却技術を提供するのを
目的とする。An object of the present invention is to provide a technology for uniform cooling in the longitudinal direction of a steel sheet in immersion cooling which has solved the above-mentioned problems.
【０００８】[0008]
【課題を解決するための手段】本発明は前記問題点を解
決するために、浸漬状態の鋼板冷却時に冷却装置内の水
温上昇による冷却能力低下を考慮して冷却途中の鋼板の
通板速度を減速することにより鋼板長手方向に均一な冷
却停止温度を得るようにしたものである。すなわち本発
明は、板厚が均一な厚鋼板を浸漬型水冷装置を用いて通
板しながら冷却するプロセスにおいて、冷却装置内での
板の通過位置に応じて冷却途中に鋼板速度を減速して通
板することを特徴とする鋼板の冷却方法である。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention considers a reduction in cooling capacity due to a rise in water temperature in a cooling device when cooling a steel sheet in an immersed state. By reducing the speed, a uniform cooling stop temperature is obtained in the longitudinal direction of the steel sheet. That is, the present invention is a process of cooling a thick steel plate having a uniform thickness while passing the plate using an immersion type water cooling device, in which the speed of the steel plate is reduced during cooling according to the passing position of the plate in the cooling device. This is a method for cooling a steel sheet, which comprises passing the sheet.
【０００９】[0009]
【作用】発明者らの調査によると、浸漬状態で冷却する
場合、鋼板を一定速度で通板すると、冷却装置内の水温
は徐々に上昇してゆき、冷却能力は鋼板先端から尾端に
かけて徐々に低下していく。しかし鋼板先端からほぼ冷
却装置長さの位置以降尾端までは、冷却能力低下は止ま
り、ほぼ一定の冷却能力の定常状態になる。According to the investigations by the inventors, when cooling in the immersion state, when the steel sheet is passed at a constant speed, the water temperature in the cooling device gradually rises, and the cooling capacity gradually increases from the tip to the tail end of the steel sheet. To decline. However, from the front end of the steel sheet to the tail end after the position substantially equal to the length of the cooling device, the cooling capacity stops decreasing, and a steady state of substantially constant cooling capacity is attained.
【００１０】本発明は前記問題点を解決するために、浸
漬状態の鋼板冷却時に冷却装置内の水温上昇による冷却
能力低下を考慮して冷却途中の鋼板の通板速度を減速す
ることにより鋼板長手方向に均一な冷却停止温度を得る
ようにしたものである。また、本発明によれば、鋼板の
先端が冷却装置内に進入してから冷却装置出側に到達し
た時点で鋼板の通板速度を減速し、その後一定速度で通
板させることにより、鋼板長手方向の冷却時間を変化さ
せることで、冷却装置の冷却能力低下にかかわらず冷却
停止温度は鋼板長手方向に一定な均一冷却が得られるよ
うになった。[0010] In order to solve the above-mentioned problems, the present invention reduces the passing speed of a steel sheet in the middle of cooling by cooling the steel sheet in a cooling state in consideration of a decrease in cooling capacity due to a rise in water temperature in a cooling device when the steel sheet is immersed. This is to obtain a uniform cooling stop temperature in the direction. Further, according to the present invention, when the leading end of the steel sheet reaches the cooling device outlet side after entering the cooling device, the sheet passing speed of the steel plate is reduced, and thereafter, the steel sheet is passed at a constant speed, whereby the steel plate longitudinal length is reduced. By changing the cooling time in the direction, it was possible to obtain a uniform and uniform cooling at the cooling stop temperature in the longitudinal direction of the steel sheet irrespective of the decrease in the cooling capacity of the cooling device.
【００１１】[0011]
【実施例】図２は、板厚22mm、長さ30m の鋼板を圧延し
たのち、鋼板温度760 ℃から、設備長さ11m の浸漬型水
冷装置により通板速度120mpmで通板冷却した時の鋼板長
手方向の冷却停止温度分布である。図３は上記鋼板の冷
却中における冷却装置の入り側、中央および出側の水温
の変化を測定したものである。鋼板先端部から冷却設備
長さ位置あたりまで約11m間は鋼板長手方向の冷却停止
温度は上昇し、それ以降は冷却停止温度はほぼ一定の温
度となる。発明者らはこのことから鋼板の冷却が進む毎
に徐々に冷却装置の冷却能力が低下することを発見し、
その原因が冷却装置内の水温上昇によるものであること
を解明した。FIG. 2 shows a steel sheet having a thickness of 22 mm and a length of 30 m, rolled, and then cooled from a steel sheet temperature of 760 ° C. by an immersion type water cooling apparatus having a facility length of 11 m at a passing speed of 120 mpm. It is a cooling stop temperature distribution in a longitudinal direction. FIG. 3 shows changes in the water temperature at the entrance, the center, and the exit of the cooling device during the cooling of the steel sheet. The cooling stop temperature in the longitudinal direction of the steel sheet rises for about 11 m from the tip of the steel sheet to the cooling facility length position, and thereafter, the cooling stop temperature becomes almost constant. The inventors have found from this that the cooling capacity of the cooling device gradually decreases as the cooling of the steel sheet progresses,
It was clarified that the cause was due to the rise in water temperature in the cooling device.
【００１２】図４に通板速度一定時の鋼板長手方向の位
置による冷却停止温度と冷却速度の変化を示す。図１に
本発明方法により冷却途中に減速を行った場合の鋼板長
手方向位置による冷却停止温度と冷却速度の変化を示
す。冷却設備の冷却能力の減少が停止する鋼板長さ位置
が先端から約 11m冷却装置内に進入した時点で通板速度
を120mpmから100mpmに減速することにより、冷却停止温
度は全長にわたって鋼板先端部の冷却停止温度に一致
し、長手方向に均一な冷却停止温度となる。FIG. 4 shows changes in the cooling stop temperature and the cooling rate depending on the position in the longitudinal direction of the steel sheet when the feeding speed is constant. FIG. 1 shows changes in the cooling stop temperature and the cooling rate depending on the position in the longitudinal direction of the steel sheet when deceleration is performed during cooling by the method of the present invention. When the length of the steel plate at which the cooling capacity of the cooling equipment stops decreasing reaches about 11m from the tip, the passing speed is reduced from 120 mpm to 100 mpm. The cooling stop temperature coincides with the cooling stop temperature and becomes uniform in the longitudinal direction.
【００１３】浸漬型水冷却装置の冷却能力低下率は鋼板
の厚さと通板速度により異なる。図５に冷却停止温度と
冷却能低下率を示す。ここで冷却能低下率をηCRとし、
鋼板先端の冷却速度を CR0とすると、鋼板尾端の冷却速
度 CR1は CR1＝ CR0×（１−ηCR） 鋼板長手方向に均一な冷却停止温度を得るための先端、
尾端の冷却時間はそれぞれ下式となる。[0013] The cooling capacity reduction rate of the immersion type water cooling device differs depending on the thickness of the steel sheet and the passing speed. FIG. 5 shows the cooling stop temperature and the cooling power decrease rate. Here, the cooling power reduction rate is defined as η CR ,
When the cooling rate of the steel sheet tip and C R0, cooling rate C R1 is C R1 = C R0 × (1 -η CR) tip for obtaining steel sheet longitudinally uniform cooling stop temperature of the steel sheet tail end,
The cooling time at the tail end is given by the following formula.
【００１４】Δ TL ＝（ T0 − T1 ）／ CR0 Δ TT ＝（ T0 − T1 ）／ CR1 ここで T0:冷却開始温度 T1:冷却停止温度 冷却装置長さをＬとすると通板冷却途中における減速量
ΔV は ΔV ＝｛（Ｌ／Δ TL ）−（Ｌ／Δ TT ）｝×60 ＝Ｌ｛ CR0／（ T0 − T1 ）− CR0（１−ηCR）／（ T0 − T1 ）｝×60 ＝｛Ｌ・ CR0／（ T0 − T1 ）｝・ηCR ×60（mpm) さらに冷却装置内の冷却水の循環速度を変化させるなど
して冷却能が変化する場合には、通板速度の減少を2 〜
3 段に分けるなど複数段で行うことにより、より木目細
かな冷却制御が可能となる。[0014] Δ T L = - (- T 1 T 0) / C R1 where T 0 (T 0 T 1) / C R0 Δ T T =: cooling stop temperature cooling device Length: cooling start temperature T 1 of deceleration amount [delta] V in the strip passing during cooling When L is ΔV = {(L / Δ T L) - (L / Δ T T)} × 60 = L {C R0 / (T 0 - T 1) - C R0 ( 1−η CR ) / (T 0 −T 1 )｝ × 60 = {L · C R0 / (T 0 −T 1 )} · η CR × 60 (mpm) If the cooling capacity changes, for example, by changing the
By performing it in multiple stages, such as dividing it into three stages, more detailed cooling control becomes possible.
【００１５】[0015]
【発明の効果】本発明は、浸漬状態での冷却装置による
冷却能力低下を冷却停止温度、板厚のパラメータで評価
し、通板冷却中の鋼板速度を途中で減速する方法を採用
したため鋼板長手方向の冷却停止温度分布を均一にする
ことができるようになった。According to the present invention, the method of evaluating the cooling capacity reduction by the cooling device in the immersion state by using parameters of the cooling stop temperature and the sheet thickness and adopting a method of reducing the steel sheet speed during the passing sheet cooling is adopted. It has become possible to make the cooling stop temperature distribution in the directions uniform.
【図面の簡単な説明】[Brief description of the drawings]
【図１】通板途中減速による鋼板長手方向位置の冷却速
度と冷却停止温度の関係を示す特性図。FIG. 1 is a characteristic diagram showing a relationship between a cooling speed at a position in a longitudinal direction of a steel sheet and a cooling stop temperature due to deceleration during passing of the sheet.
【図２】通板速度一定時の鋼板長手方向の冷却停止温度
分布を示す特性図。FIG. 2 is a characteristic diagram showing a cooling stop temperature distribution in a longitudinal direction of a steel sheet when a sheet passing speed is constant.
【図３】通板冷却時の冷却装置入り側、中央、出側の水
温変化を示す特性図。FIG. 3 is a characteristic diagram showing water temperature changes on the inlet side, center, and outlet side of the cooling device at the time of passing plate cooling.
【図４】通板速度一定時の鋼板長手方向位置の冷却速度
と冷却停止温度の関係を示す特性図。FIG. 4 is a characteristic diagram showing a relationship between a cooling speed and a cooling stop temperature at a position in a longitudinal direction of the steel plate when a passing speed is constant.
【図５】冷却停止温度、板厚による冷却能低下率の変化
を示す特性図。FIG. 5 is a characteristic diagram showing a change in a cooling capacity reduction rate depending on a cooling stop temperature and a plate thickness.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) B21B 1/00 B21B 37/00──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 6 , DB name) B21B 1/00 B21B 37/00
Claims (1)
用いて通板しながら冷却するプロセスにおいて、冷却装
置内での板の通過位置に応じて冷却途中に鋼板速度を減
速して通板することを特徴とする鋼板の冷却方法。In a process of cooling a thick steel plate having a uniform thickness while passing the plate using an immersion type water cooling device, the speed of the steel plate is reduced during cooling in accordance with the position of the plate passing through the cooling device. A method for cooling a steel sheet, comprising passing the sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4339069A JP2774030B2 (en) | 1992-12-18 | 1992-12-18 | Steel sheet cooling method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4339069A JP2774030B2 (en) | 1992-12-18 | 1992-12-18 | Steel sheet cooling method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06182416A JPH06182416A (en) | 1994-07-05 |
| JP2774030B2 true JP2774030B2 (en) | 1998-07-09 |
Family
ID=18323968
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4339069A Expired - Fee Related JP2774030B2 (en) | 1992-12-18 | 1992-12-18 | Steel sheet cooling method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2774030B2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62166014A (en) * | 1986-01-14 | 1987-07-22 | Nippon Steel Corp | Cooling method for hot steel plate with different thickness |
-
1992
- 1992-12-18 JP JP4339069A patent/JP2774030B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06182416A (en) | 1994-07-05 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |