JPS6325060B2 - - Google Patents

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Publication number
JPS6325060B2
JPS6325060B2 JP22221984A JP22221984A JPS6325060B2 JP S6325060 B2 JPS6325060 B2 JP S6325060B2 JP 22221984 A JP22221984 A JP 22221984A JP 22221984 A JP22221984 A JP 22221984A JP S6325060 B2 JPS6325060 B2 JP S6325060B2
Authority
JP
Japan
Prior art keywords
temperature
water
steel strip
water tank
cooling
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
Application number
JP22221984A
Other languages
Japanese (ja)
Other versions
JPS61104032A (en
Inventor
Yoshihiro Iida
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
Kawasaki Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Priority to JP22221984A priority Critical patent/JPS61104032A/en
Publication of JPS61104032A publication Critical patent/JPS61104032A/en
Publication of JPS6325060B2 publication Critical patent/JPS6325060B2/ja
Granted legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/573—Continuous furnaces for strip or wire with cooling

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

（産業上の利用分野） 鋼帯の連続熱処理又は類似のラインで鋼帯を冷
却水槽に通して最終冷却する鋼帯の冷却方法の改
良に関して、この明細書で述べる技術内容は、と
くに鋼帯の最終冷却に使用する冷却水槽の処理水
量の大巾な節減と、鋼帯の冷却に伴つて処理水が
得た鋼帯の熱量の有効利用を図りながら、有効な
鋼帯の最終冷却を行う方法についての開発成果を
提案するところにある。 （従来の技術） 鋼帯の連続熱処理ラインにおける最終冷却に関
しては、例えば特公昭57―11931号公報を挙げる
ことができ、ここに鋼帯を連続して浸漬通過させ
る冷却水槽として、前段水槽と後段水槽に分け、
各水槽に水温検出器と温度制御装置を配置して、
あらかじめ温度制御装置に設定した各水槽の処理
水温度の、鋼帯の浸漬通過に伴う上昇に基づき、
水温検出器の作動を介して温度制御装置により、
後段水槽については冷却水供給ポンプにて冷却水
を供給し、前段水槽については後段水槽の処理水
を各水槽の中間に備えた給水ポンプにて注湯し、
それぞれ温度調整を行うことが開示されている。 この場合、一般に後段水槽の処理水は、最終冷
却鋼帯の温度を50℃以下にするため、30〜50℃ま
での温度、また前段水槽の処理水は高温水として
再利用できるように80℃程度の温度にそれぞれ設
定される。 ここで後段水槽に供給した冷却水は、後段水槽
における処理水温の調整に役立つほか、前段水槽
への注湯の部分を占め、その処理水温の調整に利
用されるが、余水の発生が不可避で、後段水槽に
設置したドレン管から無駄に排出される不利があ
つた。 この排水は50℃以下で温度が低いため熱源とし
て回収、再利用をすることは困難であり、また鋼
帯の処理量の増大に応じ排出量も増加し、廃棄に
手間がかかる。 （発明が解決しようとする問題点） 前述したような低温排水の発生をなくし、後段
水槽に供給した全水量を、前段水槽に導いて熱交
換による熱エネルギーの回収の容易な高温処理水
として有効な利用を図りながら適切な鋼帯の最終
冷却を実現することがこの発明の目的である。 （問題を解決するための手段） この発明は、鋼帯の連続熱処理又は類似のライ
ンで複数段に分けた冷却水槽に順次鋼帯を通して
最終冷却する冷却方法において、 後段水槽直前に位置するラインの冷却帯に設置
した冷却装置によつて鋼帯を冷却すると共に、 冷却水槽の後段水槽へ、その水槽内処理水温に
応じた給水を行い、冷却水槽の前段水槽には後段
水槽の処理水をオーバフローによる注湯を行い、 この間に鋼帯の入側温度Tsと後段水槽の処理
水温度T2を下記式の関係に従い制御し、前段水
槽から高温処理水を回収する ことを特徴とする鋼帯の冷却方法である。 （70−T2）2／T2−Tw＋70≦Ts ≦（100−T2）2／T2−Tw＋100 Ts：前段水槽への鋼帯の入側温度（℃） T2：後段水槽の処理水温度（℃） Tw：冷却水温度（℃） 第１図において１は前段水槽、２は後段水槽、
３は鋼帯であり、４は鋼帯の温度検出器、５は鋼
帯の温度制御装置、６は熱処理ラインの未端で鋼
帯を冷却する冷却帯、７はその冷却装置であり、
８は後段水槽２の温度検出器、９は後段水槽２の
温度制御装置、また１０は冷却水供給ポンプ、１
１は冷却水供給管、１２は冷却水温度検出器、そ
して１３は高温処理水の回収管である。 鋼帯の温度検出器４により鋼帯３の温度を検出
し、温度制御装置５に設定した鋼帯３の冷却水槽
へ向う入側温度Tsに応じて、冷却帯６における
冷却装置７の動作を制御する。 鋼帯３は引続き前段水槽１に導入されて、鋼帯
３のもつ熱エネルギーを処理水に伝熱し、ここに
前段水槽１の処理水温度をT1℃であらわす。 鋼帯３は前段水槽１から後段水槽２へ進んで最
終冷却温度を実現するため、後段水槽２に設置し
た温度検出器８により処理水温度を検出し、その
温度上昇に応じて温度制御装置９に設定した処理
水温度T2℃となるように、冷却水供給ポンプ１
０により、温度Tw℃の冷却水を供給し、前段水
槽１には後段水槽２からのオーバーフローした処
理水を供給することで前段水槽１の処理水温度
T1を再利用可能な温度として処理水回収管１３
を経て熱交換器などに導くことができる。 ここで第１図に説明した鋼帯の最終冷却に際し
て、鋼帯の入側温度Tsと後段水槽２の処理水温
度T2の制御は、さらに第２図、第３図に示すよ
うな演算装置１４の動作によつて制御される。 第２図における演算装置の動作は、後段水槽２
へ供給される冷却水の温度Tw℃と、後段水槽２
の処理水の温度変化に応じて、あらかじめ設定し
た前段水槽１の処理水温度T1に適合すべき鋼帯
の入側温度Tsを、演算装置１４により算出し、
この算出結果と温度検出器４′により検出した鋼
帯の入側温度Ts′とを温度制御装置５にて比較
し、鋼帯の入側温度Tsとなるべき制御を行う。 この時、後段水槽２の処理水温度T2の制御は、
その水槽に設置した温度検出器８により処理水温
度を検出し、その温度上昇に応じて温度制御装置
９に設定した処理水温度T2℃となるように、冷
却水供給ポンプ１０により温度Tw℃の冷却水を
供給する。 第３図における演算装置１４の動作は、後段水
槽２へ供給される冷却水の温度Tw℃と、鋼帯の
入側温度Ts℃の変化に応じて、あらかじめ設定
した前段水槽１の処理水温度T1に適合すべき後
段水槽２の処理水温度T2を、演算装置１４によ
り算出し、この算出結果と温度検出器９により検
出した後段水槽２の処理水温度T2′とを温度制御
装置９にて比較し、後段水槽２の処理水温度T2
となるべき制御を行う。 この時、鋼帯の入側温度Tsの制御は、冷却帯
７の出側に設置した温度検出器４により鋼帯の入
側温度Ts′を検出し、その温度上昇に応じて温度
制御装置５に設定した鋼帯の入側温度Tsとなる
ように制御するのである。 （作用） 鋼帯の最終冷却過程において、後段水槽２から
前段水槽１に供給される処理水の供給量W1と後
段水槽２へ供給される冷却水の供給量W2を下記
式として表わすことができる。 W1＝Ts−T1／T1−T2×Ws×Cp …(1) W2＝T1−T2／T2−Tw×Ws×Cp …(2) ここでW1：後段水槽２から前段水槽１へ供給
される処理水の供給量（トン／ｈ） W2：後段水槽２へ供給される冷却水の供給量
（トン／ｈ） W3：鋼帯処理量（トン／ｈ） Ts：鋼帯の入側温度（℃） T1：前段水槽１の処理水温度（℃） T2：後段水槽２の処理水温度（℃） Tw：冷却水温度（℃） Cp：鋼帯の比熱（kcal／Kg℃）（Cp＝0.12） 後段水槽２および前段水槽１へ供給される冷却
水、処理水の供給量は、式(1)，(2)よりW1＝W2で
あり、下記式で表わす。 Ts＝（T1−T2）2／T2−Tw＋T1 …(3) 式(3)において、前段水槽１の処理水を高温水と
して回収するためには、その水槽で得るべき処理
水の温度範囲を設定し、鋼帯の入側温度Tsと後
段水槽２の処理水温度T2を、その温度範囲に適
応するように制御すればよい。 そこで前段水槽１の処理水温度T1の温度範囲
は、以下に述べる条件とする。 前段水槽１に導入する鋼帯の入側温度Tsが高
く、その水槽への浸漬通過に伴う処理水の沸騰で
水蒸気が多量に発生すると、鋼帯の冷却にかかる
操業が困難となるばかりでなく、水蒸気による鋼
帯の酸化が懸念されるため、前段水槽１の処理水
温度T1を100℃以下とする。 式(3)に従い前段水槽１の処理水温度T1を100℃
以下とするためには、鋼帯の入側温度Ts、後段
水槽２の処理水温度T2および冷却水温度Twを、
下記式の関係について満足させる必要がある。 Ts≦（100−T2）2／T2−Tw＋100 …(4) また、前段水槽１の処理水を再利用できる最低
温度としては、例えば連続焼鈍ラインに設置した
洗浄タンクに補給する場合など、通常70〜90℃に
設定するため、その水槽の処理水の最低温度は70
℃以上とする。式(3)において前段水槽１の処理水
温度T1を70℃以上とするためには、鋼帯の入側
温度Ts、後段水槽２の処理水温度T2および冷却
水温Twを、下記式の関係について満足させる必
要がある。 Ts≧（70−T2）2／T2−Tw＋70 …(5) 式(4)，(5)における鋼帯の入側温度Ts、後段水
槽２の処理水温度T2の温度範囲に関しては、以
下の条件とする。 後段水槽２の処理水温度T2については、通常
鋼帯の最終冷却温度を50℃以下にするため、処理
水温は30〜50℃に設定する。 鋼帯の入側温度Tsについては、鋼帯を前段水
槽１に導入する前に必要以上に冷却すると、水槽
の冷却水を高温水として回収できないばかりか、
第４図に示したように350℃の鋼帯を、110℃まで
冷却するのにガスジエツト冷却装置を用いて冷却
した場合、鋼帯の温度が150℃以下になると、必
要電力量が非常に大きくなり、冷却コストが増大
するという不具合がおこり、また、鋼帯の温度が
300℃以上を越えて最終冷却を終えると、鋼帯の
酸化皮膜が厚くなりテンパーカラーといわれる不
良が発生する。 よつて、鋼帯の入側温度Tsの下限を150℃、上
限を250℃とする。 第５図は、鋼帯の入側温度Tsと後段水槽２の
処理水温度T2との関係を、前段水槽１の処理水
温度T1をパラメータとして示したグラフである。 この図では、後段水槽２に供給される冷却水温
度Twが25℃の場合について示しており、前述し
たように鋼帯の入側温度Ts、後段水槽２の処理
水温度T2を設定し、鋼帯を冷却することで前段
水槽の処理水温度T1が、ある決まつた温度で安
定することがわかる。 また、図中に示す斜線部は、先に述べた鋼帯の
入側温度Ts、前段水槽１の処理水温度T1および
後段水槽２の処理水温度T2に対する各条件を示
した。 よつて、式(4)，(5)より得られる下記式を満足す
る各条件を設定し、鋼帯の最終冷却を行えばよい
のである。 （70−T2）2／T2−Tw＋70≦Ts ≦（100−T2）2／T2−Tw＋100 …(6) （実施例） この発明による実施例について、鋼帯処理量
Ws＝100トン／ｈ、前段水槽１の処理温度T1＝
85℃および後段水槽２へ供給される冷却水温度
Tw＝25℃として、鋼帯の冷却を行つた。（ここで
鋼帯の比熱Cp＝0.12kcal／Kg℃） 実施例 １ この発明に従う鋼帯の最終冷却に際し、後段水
槽２の処理水温度T2＝40℃に設定し、冷却水温
度Tw＝25℃と共に演算装置１４へ入力し、式(6)
に基づく鋼帯の入側温度Ts＝220℃を算出した。 上記条件による鋼帯の最終冷却で得られた結果
は、前段水槽１の処理水温度T1＝85℃、冷却水
供給量W2＝36トン／ｈ、得られた処理水量W1＝
36トン／ｈであつた。 実施例 ２ この発明に従う鋼帯の最終冷却に際し、鋼帯の
入側温度Ts＝200℃に設定し、冷却水温度Tw＝25
℃と共に演算装置１４へ入力し、式(6)に基づく後
段水槽２の処理水温度T2＝41.5℃を算出した。 上記条件による鋼帯の最終冷却で得られた結果
は、前段水槽１の処理水温度T1＝85℃、冷却水
供給量W2＝31.2トン／ｈ、得られた処理水量W1
＝31.2トン／ｈであつた。 比較例 従来の冷却方法により、鋼帯の入側温度Ts＝
200℃、後段水槽２の処理水温度T2＝40℃と設定
し、式(1)，(2)に基づく、各水槽の供給量を算出
し、この条件に従い鋼帯の最終冷却を行つた。 得られた結果は、前段水槽１の処理水温度T1
＝85℃、冷却水供給量W2＝36トン／ｈ、前段水
槽１へ供給された処理水供給量W1＝31.2トン／
ｈ、後段水槽２から排出される処理水量（W2−
W1）＝W3＝4.8トン／ｈであつた。 表―１は以上の結果をまとめたものである。 (Industrial Application Field) The technical contents described in this specification are particularly applicable to the continuous heat treatment of steel strips or the improvement of the cooling method for steel strips in which the steel strips are passed through a cooling water tank for final cooling in a similar line. A method for effective final cooling of the steel strip while drastically reducing the amount of water treated in the cooling water tank used for final cooling and effectively utilizing the heat of the steel strip obtained by the treated water as the steel strip is cooled. This is where we propose the development results for. (Prior art) Regarding the final cooling in a continuous heat treatment line for steel strips, for example, Japanese Patent Publication No. 11931/1987 describes a cooling water tank in which the steel strip is continuously immersed and passes through it. Divide into aquariums,
A water temperature detector and temperature control device are placed in each aquarium,
Based on the increase in the temperature of the treated water in each water tank, which is set in the temperature control device in advance, as the steel strip passes through the immersion,
By the temperature control device through the operation of the water temperature sensor,
Cooling water is supplied to the second stage water tank by a cooling water supply pump, and for the first stage water tank, the treated water from the second stage water tank is poured into the water tank by a water supply pump installed between each tank.
It is disclosed that temperature adjustment is performed in each case. In this case, generally the treated water in the latter stage water tank is kept at a temperature of 30 to 50 degrees Celsius in order to keep the temperature of the final cooling steel strip below 50 degrees Celsius, and the treated water in the earlier stage water tank is kept at a temperature of 80 degrees Celsius so that it can be reused as high temperature water. Each temperature is set to a certain degree. The cooling water supplied to the second-stage water tank here not only helps in adjusting the temperature of the treated water in the second-stage water tank, but also occupies the portion of pouring into the first-stage water tank and is used to adjust the temperature of the treated water, but the generation of surplus water is unavoidable. However, this had the disadvantage of wasteful discharge from the drain pipe installed in the rear water tank. Because this wastewater has a low temperature of 50°C or less, it is difficult to recover and reuse it as a heat source.Furthermore, as the amount of steel strip processed increases, the amount of wastewater discharged also increases, making disposal time-consuming. (Problems to be solved by the invention) Effective as high-temperature treated water that eliminates the generation of low-temperature wastewater as described above and guides the entire amount of water supplied to the rear-stage water tank to the front-stage water tank, where thermal energy can be easily recovered through heat exchange. It is an object of the present invention to achieve appropriate final cooling of the steel strip while making efficient use of the steel strip. (Means for Solving the Problem) The present invention provides continuous heat treatment of a steel strip or a cooling method in which the steel strip is sequentially passed through cooling water tanks divided into multiple stages in a similar line for final cooling. The steel strip is cooled by a cooling device installed in the cooling zone, and water is supplied to the downstream tank of the cooling water tank according to the temperature of the treated water in that tank, and the treated water from the downstream tank overflows into the upstream tank of the cooling water tank. During this period, the temperature T s on the inlet side of the steel strip and the temperature T 2 of the treated water in the downstream water tank are controlled according to the relationship expressed by the following formula, and high-temperature treated water is recovered from the downstream water tank. This is a cooling method. (70−T 2 ) 2 /T 2 −T w +70≦T s ≦ (100−T 2 ) 2 /T 2 −T w +100 T s : Temperature at the entrance of the steel strip into the front water tank (℃) T 2 : Temperature of treated water in rear water tank (°C) T w : Temperature of cooling water (°C) In Figure 1, 1 is the front water tank, 2 is the rear water tank,
3 is a steel strip, 4 is a temperature detector for the steel strip, 5 is a temperature control device for the steel strip, 6 is a cooling zone that cools the steel strip at the end of the heat treatment line, 7 is a cooling device for the steel strip,
8 is a temperature detector for the rear water tank 2, 9 is a temperature control device for the rear water tank 2, and 10 is a cooling water supply pump;
1 is a cooling water supply pipe, 12 is a cooling water temperature detector, and 13 is a collection pipe for high temperature treated water. The temperature of the steel strip 3 is detected by the steel strip temperature detector 4, and the cooling device 7 in the cooling zone 6 operates according to the temperature T s of the steel strip 3 on the inlet side toward the cooling water tank set in the temperature control device 5. control. The steel strip 3 is subsequently introduced into the front water tank 1, and the thermal energy of the steel strip 3 is transferred to the treated water, where the temperature of the treated water in the front water tank 1 is expressed as T 1 °C. The steel strip 3 advances from the front stage water tank 1 to the rear stage water tank 2 to achieve the final cooling temperature, so the temperature of the treated water is detected by the temperature detector 8 installed in the rear stage water tank 2, and the temperature control device 9 is activated according to the temperature rise. Cooling water supply pump 1 so that the treated water temperature T 2 °C is set at
0, the temperature of the treated water in the front water tank 1 is adjusted by supplying cooling water with a temperature of T w ℃, and supplying the overflow treated water from the rear water tank 2 to the front water tank 1.
Treated water recovery pipe 13 with T 1 as reusable temperature
can be led to a heat exchanger etc. During the final cooling of the steel strip as explained in FIG. 1, the control of the steel strip inlet temperature T s and the treated water temperature T 2 of the downstream water tank 2 is further carried out by calculations as shown in FIGS. 2 and 3. controlled by the operation of device 14. The operation of the arithmetic unit in FIG. 2 is as follows:
The temperature T w ℃ of the cooling water supplied to the downstream water tank 2
According to the temperature change of the treated water, the calculation device 14 calculates the inlet temperature T s of the steel strip that should match the preset treated water temperature T 1 of the front water tank 1,
The temperature controller 5 compares this calculation result with the steel strip entrance temperature T s ' detected by the temperature detector 4', and performs control to achieve the steel strip entrance temperature T s . At this time, the temperature T 2 of the treated water in the latter water tank 2 is controlled as follows:
The temperature of the treated water is detected by a temperature detector 8 installed in the water tank, and the temperature T w is adjusted by the cooling water supply pump 10 so that the temperature of the treated water reaches T 2 °C set in the temperature control device 9 according to the temperature rise . ℃ supply cooling water. The operation of the arithmetic unit 14 in FIG. 3 is based on the preset processing of the front water tank 1 according to changes in the temperature T w ℃ of the cooling water supplied to the rear water tank 2 and the temperature T s ℃ on the inlet side of the steel strip. The processing unit 14 calculates the temperature T 2 of the treated water in the rear water tank 2 that should match the water temperature T 1 , and uses this calculation result and the temperature T 2 ' of the treated water in the rear tank 2 detected by the temperature detector 9 as the temperature. Compared with the control device 9, the temperature of the treated water in the rear water tank 2 is T 2
Perform the control that should be achieved. At this time, the entrance temperature T s of the steel strip is controlled by detecting the entrance temperature T s ′ of the steel strip with the temperature detector 4 installed on the exit side of the cooling zone 7, and controlling the temperature according to the temperature rise. It is controlled so that the temperature at the entrance side of the steel strip is T s set in the device 5. (Function) In the final cooling process of the steel strip, the supply amount W 1 of the treated water supplied from the rear stage water tank 2 to the front stage water tank 1 and the supply amount W 2 of the cooling water supplied to the rear stage water tank 2 are expressed as the following formula. Can be done. W 1 =T s −T 1 /T 1 −T 2 ×W s ×C p …(1) W 2 =T 1 −T 2 /T 2 −T w ×W s ×C p …(2) Here W 1 : Supply amount of treated water supplied from rear stage water tank 2 to front stage water tank 1 (tons/h) W 2 : Supply amount of cooling water supplied to rear stage water tank 2 (tons/h) W 3 : Steel strip treatment Amount (ton/h) T s : Temperature at the entrance of the steel strip (°C) T 1 : Temperature of treated water in front water tank 1 (°C) T 2 : Temperature of treated water in rear water tank 2 (°C) T w : Temperature of cooling water (℃) C p : Specific heat of steel strip (kcal/Kg℃) (C p = 0.12) The supply amount of cooling water and treated water supplied to the rear water tank 2 and the front water tank 1 is calculated by formulas (1) and (2). ), W 1 = W 2 , which is expressed by the following formula. T s = (T 1 - T 2 ) 2 / T 2 - T w + T 1 ...(3) In equation (3), in order to recover the treated water in the front water tank 1 as high-temperature water, the amount of water that should be obtained in that tank is What is necessary is to set the temperature range of the treated water, and control the inlet side temperature T s of the steel strip and the treated water temperature T 2 of the rear stage water tank 2 to adapt to the temperature range. Therefore, the temperature range of the treated water temperature T1 in the front water tank 1 is set to the conditions described below. If the entrance temperature T s of the steel strip introduced into the pre-stage water tank 1 is high, and a large amount of water vapor is generated due to boiling of the treated water as it passes through the water tank, operations related to cooling the steel strip will become difficult. Since there is a concern that the steel strip may be oxidized by water vapor, the temperature T 1 of the treated water in the front water tank 1 is set to 100°C or less. According to formula (3), the temperature of the treated water in the front water tank 1 is set to 100℃.
In order to satisfy the following, the temperature T s on the inlet side of the steel strip, the temperature T 2 of the treated water in the downstream water tank 2, and the temperature T w of the cooling water must be
It is necessary to satisfy the relationship of the following formula. T s ≦ (100−T 2 ) 2 /T 2 −T w +100 …(4) In addition, the lowest temperature at which the treated water in the front water tank 1 can be reused is, for example, the temperature at which the treated water in the pre-stage water tank 1 can be replenished into a cleaning tank installed in the continuous annealing line. The minimum temperature of the treated water in that aquarium is 70°C, as it is usually set at 70 to 90°C.
℃ or higher. In formula (3), in order to make the treated water temperature T 1 of the front stage water tank 1 70°C or higher, the steel strip inlet temperature T s , the treated water temperature T 2 of the rear stage water tank 2 and the cooling water temperature T w are as follows. It is necessary to satisfy the relationship between the expressions. T s ≧ (70−T 2 ) 2 /T 2 −T w +70 …(5) Steel strip entrance temperature T s in formulas (4) and (5), and treated water temperature T 2 in the rear water tank 2 Regarding the scope, the following conditions apply. Regarding the temperature T2 of the treated water in the second stage water tank 2, the temperature of the treated water is usually set at 30 to 50°C in order to keep the final cooling temperature of the steel strip below 50°C. Regarding the inlet temperature T s of the steel strip, if the steel strip is cooled more than necessary before being introduced into the front water tank 1, not only will the cooling water in the water tank not be recovered as high temperature water,
As shown in Figure 4, when a gas jet cooling device is used to cool a steel strip at 350°C to 110°C, the amount of electricity required becomes extremely large when the temperature of the steel strip falls below 150°C. This causes problems such as increased cooling costs, and the temperature of the steel strip increases.
If the temperature exceeds 300°C and the final cooling is completed, the oxide film on the steel strip becomes thick and a defect called temper color occurs. Therefore, the lower limit of the entrance side temperature T s of the steel strip is 150°C, and the upper limit is 250°C. FIG. 5 is a graph showing the relationship between the steel strip inlet temperature T s and the treated water temperature T 2 of the rear water tank 2 using the treated water temperature T 1 of the front water tank 1 as a parameter. This figure shows the case where the temperature T w of the cooling water supplied to the rear water tank 2 is 25°C, and as described above, the temperature T s on the inlet side of the steel strip and the temperature T 2 of the treated water in the rear water tank 2 are set. However, it can be seen that by cooling the steel strip, the temperature T 1 of the treated water in the front water tank stabilizes at a certain fixed temperature. Moreover, the hatched area shown in the figure indicates each condition for the above-mentioned steel strip inlet temperature T s , treated water temperature T 1 of the front stage water tank 1, and treated water temperature T 2 of the rear stage water tank 2. Therefore, the final cooling of the steel strip can be performed by setting conditions that satisfy the following equations obtained from equations (4) and (5). (70−T 2 ) 2 /T 2 −T w +70≦T s ≦ (100−T 2 ) 2 /T 2 −T w +100 …(6) (Example) Regarding the example according to the present invention, steel strip treatment amount
W s = 100 tons/h, treatment temperature of front water tank 1 T 1 =
85℃ and cooling water temperature supplied to rear water tank 2
The steel strip was cooled at T w =25°C. (Here, the specific heat of the steel strip C p = 0.12 kcal/Kg °C) Example 1 During the final cooling of the steel strip according to the present invention, the temperature of the treated water in the downstream water tank 2 was set to T 2 = 40 °C, and the cooling water temperature T w =25℃ and input it to the arithmetic unit 14, formula (6)
The entrance temperature T s of the steel strip was calculated based on 220°C. The results obtained in the final cooling of the steel strip under the above conditions are that the temperature of the treated water in the front water tank 1 T 1 = 85°C, the amount of cooling water supplied W 2 = 36 tons/h, and the amount of treated water obtained W 1 =
It was 36 tons/h. Example 2 During the final cooling of the steel strip according to the present invention, the entrance temperature of the steel strip is set to T s =200°C, and the cooling water temperature T w =25
The temperature of the treated water in the downstream water tank 2, T 2 =41.5°C, was calculated based on equation (6). The results obtained in the final cooling of the steel strip under the above conditions are that the temperature of the treated water in the front water tank 1 T 1 = 85°C, the amount of cooling water supplied W 2 = 31.2 tons/h, and the amount of treated water obtained W 1
= 31.2 tons/h. Comparative example: Using the conventional cooling method, the entrance temperature of the steel strip T s =
The temperature of the treated water in the second stage water tank 2 was set at 200°C and the temperature of the treated water T 2 = 40°C, the supply amount of each water tank was calculated based on equations (1) and (2), and the final cooling of the steel strip was performed according to these conditions. . The obtained results show that the temperature of the treated water in the front water tank 1 is T 1
= 85°C, cooling water supply amount W 2 = 36 tons/h, treated water supply amount W 1 supplied to front stage water tank 1 = 31.2 tons/
h, the amount of treated water discharged from the rear water tank 2 (W 2 −
W 1 )=W 3 =4.8 tons/h. Table 1 summarizes the above results.

【表】 表―１に示したように、この発明による鋼帯の
最終冷却では、後段水槽２に供給される冷却水
が、オーバフローにより前段水槽１へ注湯される
ため、後段水槽２からの排水量W3＝０であるの
に対し、従来の冷却方法では、後段水槽１と前段
水槽２との間に設置された冷却水供給ポンプによ
り処理水の供給を行う以外はドレン管より排出さ
れるため、この場合、冷却水供給量W2＝36ト
ン／ｈに対し、85℃の処理水として回収された処
理水量W1＝31.2トン／ｈであり、4.8トン／ｈの
処理水が無駄に排出されたことになる。 この発明による鋼帯の冷却方法により回収した
処理水W1は、従来の冷却方法に比較して、後段
水槽２に供給された冷却水量を、すべて高温水と
して回収することができ、飛躍的に改善されたこ
とがわかる。 （発明の効果） この発明によれば、鋼帯の最終冷却に使用する
冷却水槽の処理水量の大巾な節減と、処理水が得
た鋼帯のもつ熱量の有効利用を図りながら、すべ
て高温水として回収することができると共に、適
切な鋼帯の冷却を実施することができる。[Table] As shown in Table 1, in the final cooling of the steel strip according to the present invention, the cooling water supplied to the rear water tank 2 is poured into the front water tank 1 due to overflow. The amount of water discharged is W 3 = 0, whereas in the conventional cooling method, water is discharged from the drain pipe except for supply of treated water by a cooling water supply pump installed between the rear water tank 1 and the front water tank 2. Therefore, in this case, while the cooling water supply amount W 2 = 36 tons/h, the amount of treated water recovered as 85°C treated water W 1 = 31.2 tons/h, and 4.8 tons/h of treated water was wasted. It will have been ejected. Compared to conventional cooling methods, the treated water W 1 recovered by the steel strip cooling method according to the present invention can recover all of the amount of cooling water supplied to the downstream water tank 2 as high-temperature water, which is dramatically I can see that it has improved. (Effects of the Invention) According to the present invention, the amount of treated water in the cooling water tank used for final cooling of the steel strip can be greatly reduced, and the heat of the steel strip obtained by the treated water can be effectively utilized. It can be recovered as water and appropriate cooling of the steel strip can be carried out.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、この発明に従う鋼帯の冷却方法を示
す図、第２図，３図は、本発明に係わる他の実施
例の演算装置１４の動作による制御を示す図、第
４図は、鋼帯の入側温度Tsと、必要電力との関
係を表わすグラフ、第５図は、鋼帯の入側温度
T1と処理水温度T2との関係を処理水温度T1をパ
ラメータとして示したグラフである。 １…前段水槽、２…後段水槽、３…鋼帯、４…
温度検出器、５…温度制御装置、６…冷却帯、７
…冷却装置、８…温度検出器、９…温度制御装
置、１０…冷却水供給ポンプ、１１…冷却水供給
管、１２…温度検出器、１３…処理水回収管、１
４…演算装置。 FIG. 1 is a diagram showing a method for cooling a steel strip according to the present invention, FIGS. 2 and 3 are diagrams showing control by the operation of the arithmetic unit 14 in another embodiment according to the present invention, and FIG. Figure 5 is a graph showing the relationship between the entrance temperature T s of the steel strip and the required power.
It is a graph showing the relationship between T 1 and treated water temperature T 2 using treated water temperature T 1 as a parameter. 1... Front stage water tank, 2... Back stage water tank, 3... Steel strip, 4...
Temperature detector, 5... Temperature control device, 6... Cooling zone, 7
...Cooling device, 8...Temperature detector, 9...Temperature control device, 10...Cooling water supply pump, 11...Cooling water supply pipe, 12...Temperature detector, 13...Treated water recovery pipe, 1
4...Arithmetic device.

Claims (1)

【特許請求の範囲】 １ 鋼帯の連続処理又は類似のラインで複数段に
分けた冷却水槽に、順次鋼帯を通して最終冷却す
る冷却方法において、 冷却水槽直前に位置するラインの冷却帯に設置
した冷却装置によつて鋼帯を冷却すると共に、 冷却水槽の後段水槽へ、その水槽内処理水温度
に応じた給水を行い、冷却水槽の前段水槽には後
段水槽の処理水をオーバフローによる注湯を行
い、 この間に、鋼帯の入側温度Tsと後段水槽の処
理水温度T2を下記式の関係に従い制御し、前段
水槽から高温の処理水を回収することを特徴とす
る鋼帯の冷吸方法。 （70−T2）2／T2−Tw＋70 ≦Ts≦（100−T2）2／T2−Tw＋100 ここでTs：前段水槽への鋼帯の入側温度（℃） T2：後段水槽の処理水温度（℃） Tw：冷却水温度（℃）[Scope of Claims] 1. In a cooling method in which steel strip is continuously processed or the steel strip is passed through cooling water tanks divided into multiple stages in a similar line for final cooling, the steel strip is installed in the cooling zone of the line located immediately before the cooling water tank. The steel strip is cooled by the cooling device, and water is supplied to the downstream tank of the cooling water tank according to the temperature of the treated water in that tank, and the treated water from the downstream tank is poured into the upstream tank of the cooling water tank by overflow. During this period, the temperature at the inlet side of the steel strip T s and the temperature of the treated water in the downstream water tank T 2 are controlled according to the relationship shown in the following equation, and the high-temperature treated water is recovered from the front stage water tank. How to smoke. (70−T 2 ) 2 /T 2 −T w +70 ≦T s ≦ (100−T 2 ) 2 /T 2 −T w +100 where T s : Temperature at the entrance of the steel strip into the front water tank (°C) T 2 : Temperature of treated water in downstream water tank (°C) T w : Temperature of cooling water (°C)
JP22221984A 1984-10-24 1984-10-24 Method for cooling steel strip Granted JPS61104032A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP22221984A JPS61104032A (en) 1984-10-24 1984-10-24 Method for cooling steel strip

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP22221984A JPS61104032A (en) 1984-10-24 1984-10-24 Method for cooling steel strip

Publications (2)

Publication Number Publication Date
JPS61104032A JPS61104032A (en) 1986-05-22
JPS6325060B2 true JPS6325060B2 (en) 1988-05-24

Family

ID=16778989

Family Applications (1)

Application Number Title Priority Date Filing Date
JP22221984A Granted JPS61104032A (en) 1984-10-24 1984-10-24 Method for cooling steel strip

Country Status (1)

Country Link
JP (1) JPS61104032A (en)

Also Published As

Publication number Publication date
JPS61104032A (en) 1986-05-22

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