JP2001262220A - Method for cooling steel material - Google Patents
Method for cooling steel materialInfo
- Publication number
- JP2001262220A JP2001262220A JP2000082119A JP2000082119A JP2001262220A JP 2001262220 A JP2001262220 A JP 2001262220A JP 2000082119 A JP2000082119 A JP 2000082119A JP 2000082119 A JP2000082119 A JP 2000082119A JP 2001262220 A JP2001262220 A JP 2001262220A
- Authority
- JP
- Japan
- Prior art keywords
- water
- cooled
- cooling
- temperature
- steel material
- 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.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、鋼材の冷却方法に
係わり、特に、鋼材の被冷却面に水分が残らない所謂
「乾燥状態」に維持しつつ、短時間で冷却が可能な冷却
技術に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling steel, and more particularly to a cooling technique capable of cooling in a short time while maintaining a so-called "dry state" in which no water remains on a surface to be cooled of the steel. Things.
【０００２】[0002]
【従来の技術】製鉄所では、連続鋳造された鋳片を品質
良く凝固したり、熱間圧延された鋼帯を所望通りに熱処
理したり、あるいは常温まで冷却したりするため、鋼種
やサイズの種々異なる鋼材（この場合、鋳片、鋼帯、形
鋼、鋼板等の全てを指す）を水で冷却することが多い。
従って、従来より、冷却に使用する水噴射ノズルや冷却
方法に関して多くの研究がなされ、公表されたものも数
えきれない。2. Description of the Related Art In steel mills, in order to solidify continuously cast slabs with good quality, heat-treat a hot-rolled steel strip as desired, or cool it to room temperature, the steel type and size are reduced. Various steel materials (in this case, all of slabs, steel strips, steel bars, steel plates, etc.) are often cooled with water.
Therefore, many studies have been made on water jet nozzles and cooling methods used for cooling, and a large number have been published.
【０００３】ノズルの構造についてみると、最近は、従
来から用いられている高圧水のみを噴射させる単相流体
噴霧ノズルに代わり、冷却能力を適宜調整可能とするた
めに、水と圧縮気体（主として空気）とを、それぞれの
量比を変えて混合し、冷媒とする二流体噴霧ノズルが一
般に用いられるようになってきた。例えば、特開昭５９
−２９０５５号公報は、連続鋳造された鋳片の幅方向で
水量分布をできるだけ均一にするため、「ノズルチップ
の内側端面を凹んだ球面状にすると共に、該先端部に開
設された先端開口部の入側部に凹んだ混合流体の流入ガ
イド面を設けた」ことを特徴とする気水ノズルを提案し
ている。また、特開昭６２−７４００号公報は、製造ラ
インを走行中の鋼帯の幅方向で均一な冷却を行なうた
め、気体と水の混合状態をノズル内の流路を広くした
り、狭くすることで改良することを開示している。さら
に、特開平３−２３８０６２号公報は、「気体導入部並
びに液体導入部を有する混合器に噴出オリフィスを有す
るノズル部が装着され、混合器内において気体導入部か
ら導入された気体と液体導入部から導入された液体とが
混合されてノズル部の噴出オリフィスから気液が噴出さ
れる噴霧用ノズルにおいて、噴出オリフィスからの気液
の噴霧角をミストの噴霧状態、分布を損なうことなく調
整可能な空気流を噴出する調整オリフィスを別途設け
た」ことを特徴とするノズルを開示している。つまり、
気液流に加え、該気液流を加速する空気をも同時に吹け
る構造のノズルである。With regard to the structure of the nozzle, recently, instead of a single-phase fluid spray nozzle that only uses high-pressure water, which has been conventionally used, water and compressed gas (mainly, And air) are mixed at different ratios, and a two-fluid spray nozzle serving as a refrigerant has been generally used. For example, JP
Japanese Unexamined Patent Publication No.-29055 discloses a method of making a water flow distribution as uniform as possible in the width direction of a continuously cast slab, by forming a concave spherical inner end face of a nozzle tip and a tip opening formed at the tip. And a recessed inflow guide surface for the mixed fluid is provided on the inlet side of the nozzle. " Japanese Patent Application Laid-Open No. Sho 62-7400 discloses that, in order to perform uniform cooling in the width direction of a steel strip running on a production line, a mixed state of gas and water is made wider or narrower in a nozzle. It is disclosed that it can be improved by doing so. Further, Japanese Patent Application Laid-Open No. Hei 3-28062 discloses that "a nozzle having a jet orifice is attached to a mixer having a gas introduction part and a liquid introduction part, and the gas introduced from the gas introduction part and the liquid introduction part in the mixer. The spray angle of the gas-liquid from the ejection orifice can be adjusted without impairing the spray state and distribution of the mist in the spray nozzle where the liquid introduced from the nozzle is mixed and the gas-liquid is ejected from the ejection orifice of the nozzle part A separate adjustment orifice for ejecting an air flow is separately provided. " That is,
This nozzle has a structure capable of simultaneously blowing air for accelerating the gas-liquid flow in addition to the gas-liquid flow.
【０００４】熱延鋼帯の冷却方法については、ノズルの
他、特開平２−１９７３１２号公報に開示されたよう
に、走行中の熱延鋼帯に注水された冷却水が膜沸騰する
高温域では、鋼帯搬送路の上下両側に設けた冷却水ヘッ
ダから両面に注水し、冷却水の沸騰が膜沸騰から核沸騰
に移行する遷移沸騰領域では、下面に冷却水を注水す
る」技術が開示されている。[0004] As for the method of cooling the hot-rolled steel strip, in addition to the nozzle, as disclosed in JP-A-2-197312, as described in Japanese Patent Application Laid-Open No. 2-197312, the cooling water injected into the running hot-rolled steel strip has a high temperature range in which film boiling occurs. In this technology, cooling water is injected to both sides from cooling water headers provided on both the upper and lower sides of the steel strip transport path, and cooling water is injected to the lower surface in the transition boiling region where the boiling of cooling water shifts from film boiling to nucleate boiling '' Have been.
【０００５】ところで、かかる従来の技術は、鋼鋳片、
鋼板等、鋼材の幅方向あるいは全体の均一冷却に主眼が
ある。しかしながら、鋼材の冷却では、例えば熱処理、
表面処理のように、冷却に用いた冷媒（水が多いが）を
冷却後にいつまでも該鋼材に保持しておきたくない場合
もある。つまり、残留した水が鋼材の熱処理条件に影響
を与えたり、錆や冷却ムラの発生等が生じ、製品の品質
を損なう恐れがあるからである。かかる問題を解消する
には、冷却時及び冷却後の鋼材表面が極力乾燥状態（以
下、ドライ状態ともいい、噴霧した水が被冷却面に残ら
ない状態をいう）で、且つ短時間での冷却が必要であ
る。しかしながら、このような観点での研究、開発は従
来見られず、鋼材の冷却方法は、もっと改良する余地が
あるのが現状である。[0005] Incidentally, such a conventional technique includes a steel slab,
The main focus is on uniform cooling in the width direction or the entirety of a steel material such as a steel plate. However, in cooling steel, for example, heat treatment,
As in the case of the surface treatment, there is a case where it is not desired to keep the refrigerant used for cooling (although the water is large) in the steel material forever after cooling. In other words, the remaining water may affect the heat treatment conditions of the steel material, cause rust, uneven cooling, and the like, thereby deteriorating the quality of the product. In order to solve such a problem, it is necessary to cool the steel surface during and after cooling in a dry state as much as possible (hereinafter also referred to as a dry state, in which sprayed water does not remain on the surface to be cooled) and in a short time. is necessary. However, research and development from such a viewpoint have not been seen so far, and at present, there is room for further improvement in the method of cooling steel.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、かかる事情
に鑑み、高温状態の鋼材を、水で濡らすことなく短時間
で冷却可能な鋼材の冷却方法を提供することを目的とし
ている。SUMMARY OF THE INVENTION An object of the present invention is to provide a method for cooling a steel material in a high temperature state in a short time without wetting it with water.
【０００７】[0007]
【課題を解決するたのの手段】発明者は、上記目的を達
成するため、鋼材の冷却について鋭意研究し、その成果
を本発明に具現化した。Means for Solving the Problems In order to achieve the above object, the inventor has made intensive studies on cooling of steel materials and has embodied the results in the present invention.
【０００８】すなわち、本発明は、高温の鋼材に、空気
と水の混合冷媒を噴霧し、該鋼材を常温まで冷却するに
際し、被冷却面の温度が５０℃になるまでは、該被冷却
面の温度変化に応じて前記水の水滴径を調整すると共
に、最大粒径の水滴の被冷却面における衝突速度をその
破壊衝突速度超えとして噴霧し、５０℃未満では空気の
みで冷却することを特徴とする鋼材の冷却方法である。That is, according to the present invention, when a refrigerant mixture of air and water is sprayed on a high-temperature steel material, and when the steel material is cooled to room temperature, the temperature of the surface to be cooled becomes 50 ° C. The water droplet diameter of the water is adjusted in accordance with the temperature change, and the collision speed of the water droplet having the maximum particle diameter on the surface to be cooled is sprayed at a speed exceeding the destructive collision speed, and when the temperature is lower than 50 ° C., cooling is performed only with air. It is a method of cooling a steel material.
【０００９】また、本発明は、前記水の水滴径を、被冷
却面温度＞２００℃の時は、最大粒径が１００μｍ超え
又は平均粒径が８５μｍ超えとし、２００℃≧被冷却面
温度≧５０℃の時は、最大粒径が１００μｍ以下又は平
均粒径が８５μｍ以下とすることを特徴とする鋼材の冷
却方法である。In the present invention, the water droplet diameter may be set such that the maximum particle size exceeds 100 μm or the average particle size exceeds 85 μm when the temperature of the surface to be cooled is greater than 200 ° C. This is a method for cooling a steel material, wherein the maximum particle size at 50 ° C. is 100 μm or less or the average particle size is 85 μm or less.
【００１０】さらに、本発明は、前記混合冷媒を別途に
圧縮空気で加速することを特徴とする鋼材の冷却方法で
ある。Further, the present invention is a method for cooling a steel material, wherein the mixed refrigerant is separately accelerated by compressed air.
【００１１】加えて、本発明は、前記鋼材が、製造ライ
ンを鉛直方向に走行中の鋼板あるいは鋼帯であることを
特徴とする鋼材の冷却方法である。In addition, the present invention is a method for cooling a steel material, wherein the steel material is a steel sheet or a steel strip running in a vertical direction on a production line.
【００１２】本発明によれば、鋼材の被冷却面にかかっ
た水を速やかに蒸発するようにしたので、高温状態の鋼
材を、水で濡らすことなく短時間で常温まで冷却できる
ようになる。その結果、冷却ムラ、錆等のない品質に優
れた製品鋼材が製造できるようになった。According to the present invention, since the water applied to the surface to be cooled of the steel material is quickly evaporated, the high-temperature steel material can be cooled to room temperature in a short time without being wetted with water. As a result, it has become possible to manufacture a product steel material having excellent quality without cooling unevenness and rust.
【００１３】[0013]
【発明の実施の形態】以下、図面を参照して、本発明の
実施の形態を説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１４】本発明は、製鉄所において鋼材を連続的に
冷却する工程で利用される。例えば、図６に示すような
溶鋼を連続鋳造する際の鋳片の二次冷却、図７に示すよ
うな表面処理工程で溶融亜鉛めっきを合金化した後の鋼
帯の冷却等が挙げられ、鋼材の進行方向に沿って複数の
水噴射ノズルを配列して行なわれる。これらの冷却は、
鋼材を水平に走行させて水をかける場合と、図６及び７
に示したように、鉛直方向に走行させた場合とがある
が、本発明では、後者への適用がより好ましい。The present invention is used in a step of continuously cooling steel material in an ironworks. For example, secondary cooling of a slab when continuously casting molten steel as shown in FIG. 6, cooling of a steel strip after galvannealing in a surface treatment step as shown in FIG. 7, and the like, It is performed by arranging a plurality of water injection nozzles along the traveling direction of the steel material. These cooling
The case where steel is run horizontally and water is applied, and FIGS. 6 and 7
In some cases, the vehicle travels in the vertical direction, as shown in (1). However, in the present invention, application to the latter is more preferable.
【００１５】発明者は、被冷却面にかかった水を速やか
に蒸発することが、乾燥状態を維持した冷却の要件と考
え、その要件を達成するための具体的手段について鋭意
研究した。そして、噴霧する水の水滴径を適正にするこ
と（第１要件）及び水滴の被冷却面に衝突した際の破壊
程度を増加させること（第２要件）で、目的を達成させ
たのである。The inventor considered that the rapid evaporation of water applied to the surface to be cooled is a requirement for cooling while maintaining a dry state, and has intensively studied specific means for achieving the requirement. The object was achieved by making the diameter of the water droplet to be sprayed appropriate (first requirement) and increasing the degree of destruction of the water droplet upon collision with the surface to be cooled (second requirement).
【００１６】まず、第１の要件である噴霧する水の水滴
径の適正化について説明する。First, the first requirement, that is, the optimization of the diameter of the sprayed water will be described.
【００１７】それは、水の蒸発速度が温度に依存してい
ることに着眼し、鋼材の被冷却面温度が高い時には、水
滴が大きく、低い時には、水滴が小さなるように水を噴
霧することである。鋼材はある一定速度で走行している
ので、進行方向の位置に沿って温度が低下して行く。従
って、具体的には、進行方向に沿い離隔して多段に配列
した各ノズルの噴霧する水の水滴径（実際には径分布）
を調整することでこの要件を達成する。It is focused on the fact that the evaporation rate of water depends on the temperature. When the temperature of the steel surface to be cooled is high, water droplets are large, and when the temperature is low, water is sprayed so that the water droplets are small. is there. Since the steel material travels at a certain speed, the temperature decreases along the position in the traveling direction. Therefore, specifically, the water droplet diameter (actually, the diameter distribution) of the water sprayed from each of the nozzles arranged in a multi-stage spaced apart along the traveling direction.
This requirement is achieved by adjusting.
【００１８】図１に、発明者が試験で得た噴霧水の水滴
の最大粒径及び被冷却面温度と鋼材被冷却面の湿潤状態
との関係を示す。図１に示すように、被冷却面の湿潤状
態は、噴霧水の水滴の最大粒径及び被冷却面温度に依存
していることが明らかである。FIG. 1 shows the relationship between the maximum particle size of the water droplets of the spray water and the temperature of the surface to be cooled and the wet state of the surface to be cooled of the steel material obtained by the inventors in the test. As shown in FIG. 1, it is clear that the wet state of the surface to be cooled depends on the maximum particle size of the water droplets of the spray water and the temperature of the surface to be cooled.
【００１９】なお、図１に示す被冷却面が乾き状態と湿
り状態の境界線（１）及び湿り状態と濡れ状態の境界線
（２）は、それぞれ下記（１）式及び（２）式で表され
る。The boundary line (1) between the dry and wet states and the boundary line (2) between the wet state and the wet state shown in FIG. 1 are expressed by the following equations (1) and (2), respectively. expressed.
【００２０】 Ｒmax ＝−０．００２９３３×Ｔ2＋１．２００Ｔ−２２．６７……（１） Ｒmax ＝−０．００２５９７×Ｔ2＋１．４２２Ｔ−２３．５１……（２） ここで、Ｔは被冷却面温度（℃）、Ｒmaxは噴霧水の水
滴の最大粒径を示す。また、水滴の粒径の測定は、公知
の所謂「液浸法」を用いて行い、粒径分布はフラホーフ
ェル法を用いて求めている。R max = −0.002933 × T 2 + 1.200T−22.67 (1) R max = −0.002597 × T 2 + 1.422T−23.51 (2) T indicates the surface temperature to be cooled (° C.), and R max indicates the maximum particle size of the water droplets of the spray water. In addition, the measurement of the particle size of the water droplet is performed by using a known so-called “liquid immersion method”, and the particle size distribution is obtained by using the Flachofel method.
【００２１】図１より、（１）式より上方になるように
噴霧水の水滴の最大粒径Ｒmaxを調整すれば、被冷却面
を乾き状態に維持できる。つまり、各ノズル毎に上記関
係を満足させるように、水を噴霧させるのである。From FIG. 1, if the maximum particle size R max of the water droplet of the spray water is adjusted so as to be higher than the expression (1), the surface to be cooled can be maintained in a dry state. That is, water is sprayed so as to satisfy the above relationship for each nozzle.
【００２２】しかしながら、実用に際しては、各ノズル
毎に水滴径を調整するのは、煩雑でわずらわしい。そこ
で、本発明では、前記水の水滴径を、被冷却面温度＞２
００℃の時は、最大粒径が１００μｍ超え又は平均粒径
が８５μｍ超えとし、２００℃≧被冷却面温度≧５０℃
の時は、最大粒径が１００μｍ以下又は平均粒径が８５
μｍ以下として、最低２種類の水滴径の利用でも良いよ
うに簡略化した。However, in practical use, it is complicated and troublesome to adjust the water droplet diameter for each nozzle. Therefore, in the present invention, the diameter of the water droplet is set such that the temperature of the surface to be cooled is> 2.
When the temperature is 00 ° C., the maximum particle size exceeds 100 μm or the average particle size exceeds 85 μm, and 200 ° C. ≧ cooled surface temperature ≧ 50 ° C.
When the maximum particle size is 100 μm or less or the average particle size is 85
μm or less, the structure is simplified so that at least two types of water droplet diameters may be used.
【００２３】これは、図１に基づいた下記の考えによる
ものである。This is based on the following concept based on FIG.
【００２４】（ａ）：被冷却面温度＞２００℃の時は、
被冷却面の濡れは発生しにくいため、破壊衝突速度の小
さい液滴径の大きい噴霧水を用いる方が、有効に水の蒸
発潜熱を利用できるため急速冷却が可能である。(A): When the temperature of the surface to be cooled is> 200 ° C.,
Since the surface to be cooled is less likely to be wetted, spray water having a small breaking collision velocity and a large droplet diameter can rapidly utilize the latent heat of vaporization of water, thereby enabling rapid cooling.
【００２５】（ｂ）：２００℃≧被冷却面温度≧５０℃
の時は、被冷却面が濡れ易いため、液滴径を小さくする
ことで破壊される水量を制限しつつ、破壊されない液滴
は気流にのせて排気することで冷却能力の向上と被冷却
面のドライ条件の確保が可能である。(B): 200 ° C. ≧ cooled surface temperature ≧ 50 ° C.
In this case, since the surface to be cooled is easily wet, the amount of water that is destroyed is reduced by reducing the diameter of the droplet, and the droplets that are not destroyed are exhausted in an airflow to improve the cooling capacity and increase the surface to be cooled. Dry conditions can be secured.
【００２６】つまり、図１から明らかなように、冷却面
温度が２００℃以下の場合、水滴の最大粒径が１００μ
ｍ超え又は水滴の平均粒径が８５μｍ超えの噴霧水を用
いて冷却を行った場合、被冷却面は湿った状態もしくは
濡れた状態となるためである。そして、最終的に、５０
℃＞被冷却面温度になったら、被冷却面が非常に濡れ易
いので、空気のみの冷却によって、水滴による濡れの防
止と一部湿り状態となっている箇所の乾燥を行なうので
ある。That is, as is clear from FIG. 1, when the cooling surface temperature is 200 ° C. or less, the maximum particle size of the water droplet is 100 μm.
This is because when cooling is performed using spray water having a diameter of more than m or an average particle diameter of water droplets of more than 85 μm, the surface to be cooled is in a wet state or a wet state. And finally, 50
When the temperature of the cooling target surface becomes higher than the temperature of the cooling target surface, the surface to be cooled is very easily wetted. Therefore, by cooling only the air, the wetting by the water droplets and the drying of the partially wetted portion are performed.
【００２７】なお、以下、水滴の最大粒径が１００μｍ
超え又は水滴の平均粒径が８５μｍ超えの噴霧水を用い
た直接冷却を「ミスト冷却」、水滴の最大粒径が１００
μｍ以下又は水滴の平均粒径が８５μｍ以下の噴霧水を
用いた噴霧水による直接冷却を「フォグ冷却」、送風機
からの空気を用いた空気冷却を「ファン冷却」と記す。Hereinafter, the maximum particle size of the water droplet is 100 μm.
Direct cooling using spray water having an average particle diameter of more than 85 μm or more is “mist cooling”,
Direct cooling by spray water using spray water having an average particle size of water droplets of 85 μm or less is referred to as “fog cooling”, and air cooling using air from a blower is referred to as “fan cooling”.
【００２８】本発明では、この水滴径の調整を実際に行
なうには、鋼材の温度が５０℃になるまでは、空気と水
の混合冷媒を噴霧するノズルを、５０℃未満では送風機
を使用する。そして、ノズルからの噴霧水の水滴径を噴
霧水の量と圧縮空気のノズルへの供給圧力とを変更して
調整する。発明者は、このノズルからの噴霧水の水滴径
と、噴霧水の量及び圧縮空気のノズルへの供給圧力との
関係を別途求め、それを図２に示す。図２から明らかな
ように、同一のノズルで、水噴霧用の圧縮空気の供給圧
力と噴霧水量とを変更することで、噴霧水の水滴径が調
整できる、つまり、ミスト冷却とフォグ冷却の両者が選
択可能である。In the present invention, in order to actually adjust the water droplet diameter, a nozzle for spraying a mixed refrigerant of air and water is used until the temperature of the steel material reaches 50 ° C., and a blower is used when the temperature is lower than 50 ° C. . Then, the droplet diameter of the spray water from the nozzle is adjusted by changing the amount of the spray water and the supply pressure of the compressed air to the nozzle. The inventor separately obtained the relationship between the droplet diameter of the spray water from the nozzle, the amount of the spray water, and the supply pressure of the compressed air to the nozzle, and this is shown in FIG. As is apparent from FIG. 2, the diameter of the water droplets of the spray water can be adjusted by changing the supply pressure of the compressed air for water spray and the amount of the spray water with the same nozzle, that is, both the mist cooling and the fog cooling. Is selectable.
【００２９】次に、第２の要件である噴霧水の流速につ
いて説明する。それは、噴霧水の流速を、水滴が被冷却
面に衝突した時に破壊する流速以上とすることである。
発明者が衝突流速について検討した結果を図３に示す。
図３は、平均粒径３０μｍの水滴を固体面に衝突させた
場合の例であるが、流速が２．５ｍ／ｓｅｃであると、
噴霧水のうち水滴径が３０μｍ以上の水滴が破壊され
る。また、図４に、水滴径と破壊衝突速度との関係を示
す。図４によれば、平均粒径３０μｍの噴霧水では、最
大粒径の水滴、すなわち４５μｍの水滴は、衝突速度が
２．２ｍ／ｓｅｃ以上で破壊され、最小粒径の水滴すな
わち１５μｍの水滴は、衝突速度が３．６ｍ／ｓｅｃ以
上で破壊されることが明らかである。Next, the flow rate of the spray water, which is the second requirement, will be described. That is, the flow rate of the spray water is set to be equal to or higher than the flow rate at which the water drops break when the water drops collide with the surface to be cooled.
FIG. 3 shows the result of the study of the collision velocity by the inventor.
FIG. 3 shows an example in which a water droplet having an average particle diameter of 30 μm is caused to collide with a solid surface. When the flow velocity is 2.5 m / sec,
Water droplets having a water droplet diameter of 30 μm or more in the spray water are destroyed. FIG. 4 shows the relationship between the water droplet diameter and the destructive collision speed. According to FIG. 4, in the spray water having an average particle size of 30 μm, the water droplet having the maximum particle size, that is, the water droplet having a size of 45 μm is broken at a collision velocity of 2.2 m / sec or more, and the water droplet having the minimum particle size, that is, a water droplet having a size of 15 μm is broken. It is clear that the vehicle is destroyed at a collision speed of 3.6 m / sec or more.
【００３０】これらの検討結果から、発明者は、この程
度の衝突速度は実際の冷却で実施可能であると判断し、
衝突速度を水滴の破壊速度超えとする第２の要件を考え
た。つまり、これによって、水の蒸発が起き易くすると
共に、水滴をできるだけ破壊して水の蒸発を促進するば
かりでなく、蒸発潜熟を有効に利用するようにしたので
ある。Based on the results of these studies, the inventor has determined that such a collision speed can be implemented by actual cooling.
A second requirement to make the collision speed exceed the breaking speed of the water droplet was considered. In other words, this not only facilitates the evaporation of water, but also breaks down water droplets as much as possible to promote the evaporation of water, and also makes effective use of evaporation latent ripening.
【００３１】従って、本発明は、この第２の要件を前記
第１の要件と併用することで、噴霧した水を速やかに蒸
発さえても（乾燥状態で）、従来より冷却効果が高ま
り、短時間での冷却を達成されるのである。Therefore, according to the present invention, by using the second requirement in combination with the first requirement, even if the sprayed water is quickly evaporated (in a dry state), the cooling effect is improved as compared with the conventional one, and Cooling in time is achieved.
【００３２】また、本発明では、前記水滴の被冷却面に
おける衝突速度を具体的に増す手段として、別途に準備
した圧縮空気を、水と圧縮空気を混合した冷媒とは別流
路で、同一ノズルに供給し、吐出せしめることも考え
た。すなわち、水噴霧用の圧縮空気とは別個に、ノズル
チップの前記冷媒吐出孔の外周から該冷媒の吐出方向に
圧縮空気を吐出せしめ、前記した冷却効果を高めるよう
にした。Further, in the present invention, as means for specifically increasing the collision speed of the water droplets on the surface to be cooled, separately prepared compressed air is supplied to the same flow path as the refrigerant mixed with water and compressed air in the same flow path. It was also considered to supply the liquid to the nozzle and discharge it. That is, separately from the compressed air for water spraying, compressed air is discharged in the discharge direction of the refrigerant from the outer periphery of the refrigerant discharge hole of the nozzle tip to enhance the cooling effect.
【００３３】なお、前記した平均粒径が３０μｍの水滴
の場合、被冷却面への水滴の衝突速度と被冷却面の熱伝
達係数βとの関係は、図５に示すようになる。図５よ
り、噴霧水の最大粒径の水滴の衝突速度が、最大粒径の
水滴の破壊衝突速度超えに達した時点で、水の蒸発潜熱
が有効に作用し、被冷却面の熱伝達係数βが急激に上昇
し、最小粒径の水滴がほぼ完全に破壊する衝突速度を満
足する段階で、熱伝達係数βの上昇はほぼ飽和すること
がわかる。つまり、図５の関係は、噴霧する水の最大粒
径の水滴が鋼材に衝突する速度を、最大粒径の水滴の破
壊衝突速度超えとすれば、鋼材の短時間冷却が達成でき
ることを示唆している。In the case of a water droplet having an average particle diameter of 30 μm, the relationship between the collision speed of the water droplet on the surface to be cooled and the heat transfer coefficient β of the surface to be cooled is as shown in FIG. As shown in FIG. 5, when the collision velocity of the droplet having the maximum particle diameter of the spray water exceeds the destruction collision velocity of the droplet having the maximum particle diameter, the latent heat of evaporation of the water effectively acts, and the heat transfer coefficient of the surface to be cooled. It can be seen that the rise of the heat transfer coefficient β is almost saturated at the stage where β suddenly rises and the collision velocity at which the water droplets having the minimum particle size almost completely breaks is satisfied. In other words, the relationship in FIG. 5 suggests that short-term cooling of the steel material can be achieved if the speed at which the water droplet having the maximum particle size collides with the steel material exceeds the breaking collision speed of the water droplet having the maximum particle size. ing.
【００３４】[0034]
【実施例】合金化溶融亜鉛めっき鋼板の製造ラインに、
本発明に係る冷却方法を適用した。[Example] In the production line of galvannealed steel sheet,
The cooling method according to the present invention was applied.
【００３５】つまり、前記図７に示した製造ラインにお
いて、合金化炉から抜け出し、鉛直方向に走行している
鋼帯の表面に、水と圧縮空気からなる混合冷媒に加速用
空気を加えて、鋼帯に吹き付けた。その際のノズル配置
状況を図８に示す。鋼帯１の表面温度は、４５０℃、走
行速度は１００ｍ／ｍｉｎである。また，鋼帯１の幅
は、１２００ｍｍであったので、幅方向に長いスリット
状開口を有するノズル２を水平にして６５段に配置し、
高さ方向における各ノズル２の間隔は、３００ｍｍとし
た。各ノズル２からの混合冷媒３の噴霧条件、及び圧縮
空気の流量を表１に示す。つまり、表１から明らかなよ
うに、鋼帯１の進行方向に沿って鋼帯１の温度変化が生
じるので、本発明に従い、その温度に応じて混合冷媒３
の噴霧条件を変化させた。また、別途の圧縮空気での加
速も行なっている。That is, in the production line shown in FIG. 7, the acceleration air is added to the mixed refrigerant consisting of water and compressed air on the surface of the steel strip running out of the alloying furnace and running in the vertical direction. Sprayed on steel strip. FIG. 8 shows the nozzle arrangement at that time. The surface temperature of the steel strip 1 is 450 ° C., and the running speed is 100 m / min. Also, since the width of the steel strip 1 was 1200 mm, the nozzles 2 having slit-shaped openings long in the width direction were horizontally arranged at 65 steps,
The interval between the nozzles 2 in the height direction was 300 mm. Table 1 shows the spray conditions of the mixed refrigerant 3 from each nozzle 2 and the flow rate of the compressed air. In other words, as is apparent from Table 1, the temperature of the steel strip 1 changes along the traveling direction of the steel strip 1. Therefore, according to the present invention, the mixed refrigerant 3 changes according to the temperature.
Was changed. In addition, acceleration with separate compressed air is also performed.
【００３６】その結果、本発明の実施中は、鋼帯１下方
への水だれは一切起きなかった。鋼帯１の冷却状況を温
度で評価し、図９に示す。図９より、４５０℃より１０
０℃まで、１２秒分という短時間で冷却ができている。As a result, no dripping occurred below the steel strip 1 during the implementation of the present invention. The cooling condition of the steel strip 1 was evaluated by temperature and is shown in FIG. According to FIG.
Cooling to 0 ° C. was completed in a short time of 12 seconds.
【００３７】一方、従来通りの混合冷媒の噴霧条件（表
１及び図９のミスト冷却のみに相当）で冷却した場合
も、表１及び図９に同時に示すが、水だれが発生した。On the other hand, when cooling was performed under the conventional spray condition of the mixed refrigerant (corresponding to only the mist cooling in Table 1 and FIG. 9), dripping occurred, as shown in Table 1 and FIG. 9 simultaneously.
【００３８】なお、表１に示した本発明の実施条件は、
フォグ冷却時（Ｎｏ．１５ノズルからＮｏ．６５ノズル
まで）は、水滴の平均粒径が３０μｍの噴霧水であり、
噴霧水の最大粒径４５μｍの水滴が被冷却面に速度２．
２ｍ／ｓｅｃ以上で衝突することになる。The operating conditions of the present invention shown in Table 1 are as follows:
At the time of fog cooling (from No. 15 nozzle to No. 65 nozzle), the spray water has an average particle diameter of water droplets of 30 μm,
A droplet having a maximum particle size of 45 μm of the spray water is applied to the surface to be cooled at a speed of 2.
The collision occurs at 2 m / sec or more.
【００３９】[0039]
【表１】 [Table 1]
【００４０】なお、上記実施例は、合金化溶融亜鉛めっ
き鋼帯の冷却の場合であるが、本発明は、それに限ら
ず、連続鋳造機での鋳片の二次冷却、鋼板の連続焼入れ
のための冷却等にも、噴霧条件を適宜選択することで適
用できることは、言うまでもない。Although the above embodiment is directed to the case of cooling a galvannealed steel strip, the present invention is not limited to this. For example, secondary cooling of a slab by a continuous casting machine and continuous quenching of a steel sheet. Needless to say, it can be applied to cooling for the purpose by appropriately selecting the spraying conditions.
【００４１】[0041]
【発明の効果】以上述べたように、本発明により、高温
の鋼材を、その表面を濡らすことはく、短時間で冷却す
ることが可能となる。その結果、冷却ムラ、錆等のない
品質に優れた製品鋼材が製造できるようになった。As described above, according to the present invention, a high-temperature steel material can be cooled in a short time without wetting the surface thereof. As a result, it has become possible to manufacture a product steel material having excellent quality without cooling unevenness and rust.
【図１】噴霧水の水滴の最大粒径及び被冷却面温度と、
被冷却面の湿潤状態との関係を示す図である。FIG. 1 shows the maximum particle diameter of spray water droplets and the temperature of a surface to be cooled,
It is a figure showing the relation with the wet state of the surface to be cooled.
【図２】噴霧水量及び水噴霧用の圧縮空気のノズルへの
供給圧力と、噴霧水の液滴径との関係を示す図である。FIG. 2 is a diagram showing a relationship between a spray water amount, a supply pressure of compressed air for spraying water to a nozzle, and a droplet diameter of the spray water.
【図３】平均粒径３０μｍの水滴が、衝突速度２．５ｍ
／ｓｅｃで固体面に衝突した時の水滴の破壊割合を示す
グラフである。FIG. 3 shows that a water droplet having an average particle diameter of 30 μm has a collision velocity of 2.5 m.
4 is a graph showing the destruction rate of water droplets when colliding with a solid surface at / sec.
【図４】液滴径と破壊衝突速度との関係を示すグラフで
ある。FIG. 4 is a graph showing a relationship between a droplet diameter and a breaking collision velocity.
【図５】被冷却面への水滴の衝突速度と被冷却面の熱伝
達係数との関係を示すグラフである。FIG. 5 is a graph showing a relationship between a collision speed of a water droplet on a surface to be cooled and a heat transfer coefficient of the surface to be cooled.
【図６】一般的な連続鋳造機で鋳片の二次冷却を示す図
である。FIG. 6 is a view showing secondary cooling of a slab in a general continuous casting machine.
【図７】一般的な合金化溶融亜鉛めっき鋼板の製造ライ
ンを示す図である。FIG. 7 is a view showing a production line for a general alloyed hot-dip galvanized steel sheet.
【図８】図７に示した合金化炉の下流に配置した冷却ノ
ズル群例を示す図である。8 is a diagram showing an example of a cooling nozzle group arranged downstream of the alloying furnace shown in FIG.
【図９】本発明に係る鋼材の冷却方法を実施した結果と
しての、鋼材の温度変化を示す図である。FIG. 9 is a diagram showing a temperature change of the steel material as a result of performing the method of cooling the steel material according to the present invention.
１ 鋼帯 ２ ノズル ３ 混合冷媒 ４ 取鍋 ５ タンディッシュ ６ 二次冷却ノズル ７ ピンチロール ８ 鋳片 ９ めっき浴槽 １０ スナウト １１ シンクロール １２ サポートロール １３ ワイピングノズル １４ 合金化炉 １５ 送風機 １６ めっき浴 １７ 空気 Reference Signs List 1 steel strip 2 nozzle 3 mixed refrigerant 4 ladle 5 ladle 5 tundish 6 secondary cooling nozzle 7 pinch roll 8 cast piece 9 plating bath 10 snout 11 sink roll 12 support roll 13 wiping nozzle 14 alloying furnace 15 blower 16 plating bath 17 air
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4E004 KA11 KA17 MC02 4K034 AA02 AA19 BA04 CA04 DB03 FA01 FA05 FB03 4K043 AA01 CB04 EA04 FA03 FA13 HA04 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E004 KA11 KA17 MC02 4K034 AA02 AA19 BA04 CA04 DB03 FA01 FA05 FB03 4K043 AA01 CB04 EA04 FA03 FA13 HA04
Claims (4)
霧し、該鋼材を常温まで冷却するに際し、 被冷却面の温度が５０℃になるまでは、該被冷却面の温
度変化に応じて前記水の水滴径を調整すると共に、最大
粒径の水滴の被冷却面における衝突速度をその破壊衝突
速度超えとして噴霧し、５０℃未満では空気のみで冷却
することを特徴とする鋼材の冷却方法。1. A method in which a mixture of air and water is sprayed onto a high-temperature steel material, and when the steel material is cooled to room temperature, the temperature of the surface to be cooled is changed until the temperature of the surface to be cooled reaches 50 ° C. The water droplet diameter of the water is adjusted accordingly, and the collision speed of the water droplet having the maximum particle size on the surface to be cooled is sprayed as exceeding the destruction collision speed, and at a temperature lower than 50 ° C., the steel material is cooled only with air. Cooling method.
０℃の時は、最大粒径が１００μｍ超え又は平均粒径が
８５μｍ超えとし、２００℃≧被冷却面温度≧５０℃の
時は、最大粒径が１００μｍ以下又は平均粒径が８５μ
ｍ以下とすることを特徴とする請求項１記載の鋼材の冷
却方法。2. The method according to claim 1, wherein the diameter of the water droplet is set such that the surface temperature to be cooled is> 20.
At 0 ° C., the maximum particle size exceeds 100 μm or the average particle size exceeds 85 μm. When 200 ° C. ≧ cooled surface temperature ≧ 50 ° C., the maximum particle size is 100 μm or less or the average particle size is 85 μm.
2. The method for cooling steel material according to claim 1, wherein the temperature is not more than m.
ることを特徴とする請求項１又は２記載の鋼材の冷却方
法。3. The method according to claim 1, wherein the mixed refrigerant is separately accelerated by compressed air.
行中の鋼板あるいは鋼帯であることを特徴とする請求項
１〜３のいずれかに記載の鋼材の冷却方法。4. The method for cooling steel according to claim 1, wherein the steel is a steel plate or a steel strip running in a vertical direction on a production line.
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| JP2004010960A (en) * | 2002-06-06 | 2004-01-15 | Nippon Steel Corp | Cooling process in process line for manufacturing industrial product |
| JP2007118042A (en) * | 2005-10-28 | 2007-05-17 | Jfe Steel Kk | Secondary cooling method for continuously cast slab |
| JP2008221316A (en) * | 2007-03-15 | 2008-09-25 | Jfe Steel Kk | Method for cooling continuously cast slab |
| JP2010253525A (en) * | 2009-04-28 | 2010-11-11 | Jfe Steel Corp | Secondary cooling method for continuously cast slab by two fluid mist spray nozzle |
| JP2014050873A (en) * | 2012-09-10 | 2014-03-20 | Nippon Steel & Sumitomo Metal | Secondary cooling method for continuous casting |
| CN103740904A (en) * | 2009-12-11 | 2014-04-23 | 株式会社Ihi | Mist cooling apparatus, heat treatment apparatus, and mist cooling method |
| JP2015055001A (en) * | 2013-09-13 | 2015-03-23 | Ｊｆｅスチール株式会社 | Steel sheet cooling device and steel sheet cooling method |
| WO2017163732A1 (en) * | 2016-03-23 | 2017-09-28 | 株式会社Ihi | Cooling device and thermal treatment device |
| JP2019147087A (en) * | 2018-02-27 | 2019-09-05 | Ｊｆｅスチール株式会社 | Mist nozzle spray type cooling method and cooling device |
| JP7444149B2 (en) | 2020-12-01 | 2024-03-06 | Ｊｆｅスチール株式会社 | Cooling method and cooling device for coiled hot rolled steel sheet |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004010960A (en) * | 2002-06-06 | 2004-01-15 | Nippon Steel Corp | Cooling process in process line for manufacturing industrial product |
| JP2007118042A (en) * | 2005-10-28 | 2007-05-17 | Jfe Steel Kk | Secondary cooling method for continuously cast slab |
| JP2008221316A (en) * | 2007-03-15 | 2008-09-25 | Jfe Steel Kk | Method for cooling continuously cast slab |
| JP2010253525A (en) * | 2009-04-28 | 2010-11-11 | Jfe Steel Corp | Secondary cooling method for continuously cast slab by two fluid mist spray nozzle |
| CN103740904B (en) * | 2009-12-11 | 2016-08-24 | 株式会社Ihi | Spray cooling device, annealing device and Spray Way |
| CN103740904A (en) * | 2009-12-11 | 2014-04-23 | 株式会社Ihi | Mist cooling apparatus, heat treatment apparatus, and mist cooling method |
| EP2511385A4 (en) * | 2009-12-11 | 2015-08-26 | Ihi Corp | Mist cooling apparatus, heat treatment apparatus, and mist cooling method |
| US9187795B2 (en) | 2009-12-11 | 2015-11-17 | Ihi Corporation | Mist cooling apparatus, heat treatment apparatus, and mist cooling method |
| JP2014050873A (en) * | 2012-09-10 | 2014-03-20 | Nippon Steel & Sumitomo Metal | Secondary cooling method for continuous casting |
| JP2015055001A (en) * | 2013-09-13 | 2015-03-23 | Ｊｆｅスチール株式会社 | Steel sheet cooling device and steel sheet cooling method |
| WO2017163732A1 (en) * | 2016-03-23 | 2017-09-28 | 株式会社Ihi | Cooling device and thermal treatment device |
| JP2019147087A (en) * | 2018-02-27 | 2019-09-05 | Ｊｆｅスチール株式会社 | Mist nozzle spray type cooling method and cooling device |
| JP7444149B2 (en) | 2020-12-01 | 2024-03-06 | Ｊｆｅスチール株式会社 | Cooling method and cooling device for coiled hot rolled steel sheet |
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