JP2014050875A - Cooling device, manufacturing apparatus and manufacturing method of hot rolled steel sheet - Google Patents
Cooling device, manufacturing apparatus and manufacturing method of hot rolled steel sheet Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 222
- 239000010959 steel Substances 0.000 title claims abstract description 222
- 238000001816 cooling Methods 0.000 title claims abstract description 123
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 38
- 239000000498 cooling water Substances 0.000 claims abstract description 68
- 238000005096 rolling process Methods 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 16
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 7
- 230000008569 process Effects 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 45
- 238000002347 injection Methods 0.000 claims description 20
- 239000007924 injection Substances 0.000 claims description 20
- 238000001514 detection method Methods 0.000 abstract description 7
- 239000007921 spray Substances 0.000 description 35
- 239000013078 crystal Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 8
- 238000005452 bending Methods 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000008400 supply water Substances 0.000 description 2
- 239000002352 surface water Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001141 propulsive effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Description
本発明は、熱延鋼板の冷却装置、製造装置、及び、製造方法に関する。本発明は、特に、微細結晶粒を有する熱延鋼板を製造する際に好適に用いられる熱延鋼板の冷却装置及び製造装置、並びに、この熱延鋼板の冷却装置を用いる熱延鋼板の製造方法に関する。 The present invention relates to a cooling apparatus, a manufacturing apparatus, and a manufacturing method for a hot-rolled steel sheet. In particular, the present invention relates to a hot-rolled steel sheet cooling apparatus and manufacturing apparatus that are preferably used when manufacturing a hot-rolled steel sheet having fine crystal grains, and a hot-rolled steel sheet manufacturing method using the hot-rolled steel sheet cooling apparatus. About.
自動車用や構造材用等として用いられる鋼材は、強度、加工性、靭性といった機械的特性に優れることが求められ、これらの機械的特性を総合的に高めるには、熱延鋼板の結晶粒を微細化することが有効である。そのため、微細結晶粒を有する熱延鋼板を得るための製造方法が数多く模索されてきている。また、結晶粒を微細化すれば、合金元素の添加量を削減しても優れた機械的性質を具備した高強度熱延鋼板を製造することが可能になる。 Steel materials used for automobiles, structural materials, etc. are required to have excellent mechanical properties such as strength, workability, and toughness. It is effective to reduce the size. Therefore, many manufacturing methods for obtaining a hot rolled steel sheet having fine crystal grains have been sought. Further, if the crystal grains are refined, it is possible to produce a high-strength hot-rolled steel sheet having excellent mechanical properties even if the addition amount of the alloy element is reduced.
熱延鋼板の結晶粒の微細化方法としては、熱間仕上圧延の特に後段において、高圧下圧延を行ってオーステナイト粒を微細化するとともに粒内に圧延歪を蓄積させ、冷却後（又は変態後）に得られるフェライト粒の微細化を図る方法等が知られている。そして、オーステナイト粒の再結晶や回復を抑制してフェライト変態を促進させるという観点からは、圧延後の短時間で鋼板を所定の温度以下（例えば、７２０℃以下）まで冷却することが有効である。すなわち、微細結晶粒を有する熱延鋼板を製造するためには、熱間仕上圧延に引き続き、従来よりも早く冷却することが可能な冷却装置を設置し、圧延後の鋼板を急冷することが有効である。 As a method for refining crystal grains of hot-rolled steel sheet, particularly in the latter stage of hot finish rolling, high-pressure rolling is performed to refine austenite grains and accumulate rolling strain in the grains, after cooling (or after transformation) And the like, and the like. And, from the viewpoint of suppressing recrystallization and recovery of austenite grains and promoting ferrite transformation, it is effective to cool the steel sheet to a predetermined temperature or lower (for example, 720 ° C. or lower) in a short time after rolling. . In other words, in order to manufacture hot rolled steel sheets with fine crystal grains, it is effective to install a cooling device that can cool faster than before, followed by hot finish rolling, and rapidly cool the rolled steel sheet. It is.
熱間仕上圧延後の鋼板の冷却に着目した技術として、例えば特許文献１には、鋼帯に対して圧力が互いにバランスするよう冷却水を噴射する上面冷却ボックスおよび下面冷却ボックスを備えた、急速冷却装置である第１の冷却装置を、熱間最終仕上圧延機の直近に設け、この第１の冷却装置の下流側に緩冷却装置である第２の冷却装置を設けた熱延鋼帯の冷却装置が開示されている。また、特許文献２には、通板初期の鋼板の波うち（ウェービング）をレーザービーム等を用いて検知し、このウェービングが消失してから冷却水の注水を開始する、熱間圧延時の冷却水注水開始制御方法が開示されている。また、特許文献３には、熱間圧延機で圧延された通板中の鋼板の上方への変位をマイクロ波ドップラー板速計又はレーザー距離計等を用いて検知し、操業トラブル回避の必要に応じて一部の冷却水供給を停止する熱延鋼帯の製造方法が開示されている。 As a technique focusing on cooling of a steel sheet after hot finish rolling, for example, Patent Document 1 includes a rapid cooling box including an upper surface cooling box and a lower surface cooling box that inject cooling water so that the pressure is balanced against the steel strip. The first cooling device as a cooling device is provided in the immediate vicinity of the hot final finishing rolling mill, and the hot rolled steel strip provided with the second cooling device as a slow cooling device on the downstream side of the first cooling device. A cooling device is disclosed. Further, Patent Document 2 discloses a cooling process during hot rolling, in which a wave (waving) of a steel sheet in the initial stage of sheet passing is detected using a laser beam or the like, and water injection is started after the disappearance of the waving. A water injection start control method is disclosed. Further, in Patent Document 3, the upward displacement of a steel plate in a sheet plate rolled by a hot rolling mill is detected using a microwave Doppler plate speedometer or a laser distance meter, etc., and it is necessary to avoid operational troubles. Accordingly, a method of manufacturing a hot-rolled steel strip that stops part of the cooling water supply is disclosed.
熱間仕上圧延後の鋼板は３００〜５００ｍｍ程度の間隔で並ぶ搬送ローラー（以下において、単に「ローラー」ということがある。）上を走行する。各ローラーの最上点を結ぶ線がパスラインである。鋼板には自重および冷却時には板上の滞留水の重みも加わるため、ローラー間で多少はパスラインより下方に撓むこともあるが、先端が巻き取り装置に達し張力が付与されれば、通常は撓みがほぼ無くなりパスライン上で安定して搬送される。 The steel sheet after hot finish rolling runs on transport rollers (hereinafter sometimes simply referred to as “rollers”) arranged at intervals of about 300 to 500 mm. A line connecting the top points of the rollers is a pass line. Since the steel plate is subject to its own weight and the weight of the accumulated water on cooling, it may be bent slightly below the pass line between the rollers, but if the tip reaches the winding device and tension is applied, it is normal. Is almost free from bending and is stably conveyed on the pass line.
鋼板を急冷するためには、高圧・大流量の冷却水を鋼板の上面、下面に向けて噴射する必要がある。通常の圧延後冷却では、冷却水の給水圧力が０．２〜０．３ＭＰａ、鋼板面での流量密度が０．５〜２ｍ３／（ｍ２・ｍｉｎ）程度であるのに対し、急冷のためには例えば給水圧力０．５ＭＰａ以上、流量密度１０ｍ３／（ｍ２・ｍｉｎ）以上が必要とされる。そのため、鋼板には自重や滞留水重量以外に上下面を押す大きな力が作用し、それらが適切なバランスを保っていないと、たとえ張力が付与された状態であってもパスラインに対し浮き上ったり沈み込んだりしてしまう。 In order to rapidly cool a steel plate, it is necessary to inject high-pressure, large-flow cooling water toward the upper and lower surfaces of the steel plate. In normal post-rolling cooling, the cooling water supply pressure is 0.2 to 0.3 MPa, and the flow density on the steel sheet surface is about 0.5 to 2 m 3 / (m 2 · min), whereas rapid cooling For this purpose, for example, a water supply pressure of 0.5 MPa or more and a flow density of 10 m 3 / (m 2 · min) or more are required. Therefore, a large force that pushes the upper and lower surfaces acts on the steel plate in addition to its own weight and accumulated water weight, and if they do not maintain an appropriate balance, they will float up against the pass line even if tension is applied. Or sink.
鋼板がパスラインから浮き上がると、位置が定まらなくなることに加えローラーからの推進力が伝わらなくなるため、走行が不安定となる。反対に鋼板がローラー間で下方に沈み込む場合も、ある限度を超えると鋼板がばたつき始め走行が不安定になることがある。また、ローラー間にガイドが設置されている場合には、鋼板下面がこれに接触し、スリ疵が生じることもある。 When the steel plate is lifted from the pass line, the position becomes unstable and the propulsive force from the roller is not transmitted, so that traveling becomes unstable. On the other hand, when the steel plate sinks downward between the rollers, the steel plate may start fluttering when it exceeds a certain limit, and running may become unstable. In addition, when a guide is installed between the rollers, the lower surface of the steel plate may come into contact with it, and a scratch may occur.
鋼板を急冷するためには、冷却水を連続的に噴射することが有効であり、鋼板の下面側では搬送ローラーの間隔を極力広げることが有効である。しかしローラーの間隔を広げると鋼板の走行が不安定になり易い。冷却水が鋼板に向けて広がりながら噴射されるスプレー形式のノズルから噴射された冷却水を鋼板に衝突させることによって鋼板を急冷する場合、鋼板の走行高さが変化するとノズルと鋼板との間の距離が変わり、冷却水が鋼板に衝突する際の広がり量も変ってしまう。また、鋼板幅方向に均一な冷却を行うために、ノズルはスプレーの広がりを考慮した所定の間隔で複数個配置されているが、鋼板の走行高さがパスラインからずれると、鋼板幅方向の均一冷却性も失われる。したがって、このような事態を回避するためには、急冷する場合であっても鋼板を安定して走行させること（鋼板の走行高さを安定化させること）が重要である。 In order to rapidly cool the steel plate, it is effective to continuously inject cooling water, and it is effective to widen the interval between the conveying rollers as much as possible on the lower surface side of the steel plate. However, if the distance between the rollers is increased, the running of the steel sheet tends to become unstable. When the steel sheet is rapidly cooled by colliding the cooling water sprayed from the spray type nozzle that is sprayed while the cooling water spreads toward the steel sheet, when the steel sheet travels rapidly, the distance between the nozzle and the steel sheet changes. The distance changes, and the amount of spread when the cooling water collides with the steel sheet also changes. Moreover, in order to perform uniform cooling in the steel plate width direction, a plurality of nozzles are arranged at predetermined intervals in consideration of the spread of the spray, but if the running height of the steel plate deviates from the pass line, Uniform cooling is also lost. Therefore, in order to avoid such a situation, it is important to make the steel plate run stably (stabilize the running height of the steel plate) even in the case of rapid cooling.
特許文献１には、鋼板から見て上下対称の位置に同形態の冷却ボックスを設置し、上下等圧力で冷却水を噴射する方法が開示されている。しかしながら、特許文献１では、鋼板の上面側と下面側とで冷却装置の位置や形態が異なる場合に鋼板の走行高さを安定化させることについては検討されておらず、鋼板の上面に滞留する冷却水や鋼板の自重の影響についても検討されていない。また、特許文献２には熱間圧延時の冷却水注水開始制御方法が開示されているが、注水中に鋼板の走行高さを安定化させることについては検討されていない。なお、特許文献２で使用しているレーザー等の光学センサーは飛散水や蒸気の影響を受けやすいため、冷却開始後の使用は困難である。また、特許文献３に開示されている技術では、安定した鋼板走行と適正な冷却とを両立させることは困難である。また、この技術には、上面冷却の注水密度が高くマイクロ波やレーザー光を通す空間が制約されていたり、鋼板上に滞留水が存在したりする場合には、鋼板変位の検知自体が難しいという問題もある。特許文献３に開示されているような、板速計で上方向速度を測定する方法では、そもそも上方向速度が大きい顕著な波うちしか検知できないという問題もある。特許文献１乃至特許文献３に開示されている技術とは異なる、鋼板の走行高さを検知する手段としては、渦電流式変位計等を例示することができる。水に強いので、耐熱性さえ確保できれば使用することも可能だが、渦電流式変位計は測定レンジに応じてセンサーヘッド部が大きくなるため、下面冷却を阻害してしまう虞がある。 Patent Document 1 discloses a method in which a cooling box having the same configuration is installed in a vertically symmetrical position when viewed from a steel plate, and cooling water is jetted at equal vertical pressure. However, in patent document 1, when the position and form of a cooling device differ in the upper surface side and lower surface side of a steel plate, it is not examined about stabilizing the running height of a steel plate, and it stays on the upper surface of a steel plate. The influence of cooling water and the weight of the steel sheet has not been studied. Further, Patent Document 2 discloses a cooling water injection start control method during hot rolling, but it has not been studied to stabilize the traveling height of the steel sheet during water injection. In addition, since the optical sensor such as a laser used in Patent Document 2 is easily affected by splashed water or steam, it is difficult to use after the start of cooling. Moreover, with the technique disclosed in Patent Document 3, it is difficult to achieve both stable steel plate running and proper cooling. In addition, this technology is difficult to detect the displacement of the steel plate itself when the water injection density of the top surface cooling is high and the space through which microwaves or laser light passes is restricted, or when stagnant water exists on the steel plate. There is also a problem. In the method of measuring the upward speed with a plate speedometer as disclosed in Patent Document 3, there is also a problem that only a significant wave having a large upward speed can be detected in the first place. As means for detecting the traveling height of the steel sheet, which is different from the techniques disclosed in Patent Documents 1 to 3, an eddy current displacement meter or the like can be exemplified. Since it is water resistant, it can be used as long as it has sufficient heat resistance. However, the eddy current displacement meter has a large sensor head depending on the measurement range, which may hinder bottom surface cooling.
そこで、本発明は、高圧且つ大流量の冷却水を衝突させることによって鋼板を急冷する場合であっても、鋼板を安定して走行させることが可能な熱延鋼板の冷却装置および製造装置、並びに、当該熱延鋼板の冷却装置を用いる熱延鋼板の製造方法を提供することを課題とする。 Accordingly, the present invention provides a hot-rolled steel sheet cooling apparatus and manufacturing apparatus capable of stably running a steel sheet, even when the steel sheet is rapidly cooled by colliding high-pressure and large-flow cooling water, and An object of the present invention is to provide a method for producing a hot-rolled steel sheet using the cooling device for the hot-rolled steel sheet.
本発明者らは、急冷時の鋼板走行高さの安定化について研究を行った結果、搬送ローラーに掛かる荷重を計測し、これを元に上下冷却水噴射の圧力を調整する方法を案出した。 As a result of studying the stabilization of the running height of the steel sheet during rapid cooling, the present inventors have devised a method for measuring the load applied to the transport roller and adjusting the pressure of the upper and lower cooling water jets based on this measurement. .
鋼板の走行高さを安定化させる前提条件は、鋼板と搬送ローラーとの接触を保つこと、すなわち搬送ローラーに掛かる荷重を正値とすることである。搬送ローラーに掛かる荷重を計測する方式（荷重計測方式）では負値は計測できないが、この荷重が常に正値になるように、鋼板の上面および下面に向けて噴射される冷却水の噴射圧力を調整すれば良く、荷重計測方式でも、鋼板の走行高さの安定化制御を実施することができる。 The precondition for stabilizing the running height of the steel sheet is to maintain contact between the steel sheet and the transport roller, that is, to set the load applied to the transport roller to a positive value. Although the negative value cannot be measured with the method of measuring the load applied to the transport roller (load measurement method), the injection pressure of the cooling water injected toward the upper and lower surfaces of the steel sheet is set so that this load is always positive. It is only necessary to adjust, and stabilization control of the running height of the steel sheet can be performed even with the load measurement method.
搬送ローラーに掛かる荷重の計測は、搬送ローラー両端の軸箱（チョック）下面とそれを支持する架台との間にロードセルを設置することで実現できる。搬送ローラーおよび軸箱の重量に対し相対的に小さい荷重を精度良く計測する必要があるため、ロードセルの型式や設置部の形状や加工精度等には注意を要するが、荷重計測手法としては一般的で、耐環境性や耐久性等の点でも信頼でき、鋼板の高さを直接計測する従来提案方法に比べ、はるかに安定した計測が可能である。 Measurement of the load applied to the transport roller can be realized by installing a load cell between the lower surface of the axle box (chock) at both ends of the transport roller and the gantry supporting it. Because it is necessary to accurately measure a relatively small load with respect to the weight of the transport roller and axle box, care is required for the type of load cell, the shape of the installation part, processing accuracy, etc. Therefore, it is reliable in terms of environmental resistance, durability, etc., and much more stable measurement is possible compared to the conventionally proposed method of directly measuring the height of a steel plate.
鋼板の上方から供給された冷却水の衝突力が大きければ、搬送ローラーに掛かる荷重が大きくなり、同時に搬送ローラー間での鋼板の沈み込み（撓み）も大きくなる。撓みは隣り合う２本の搬送ローラー間の中央で最大となるが、その最大撓み量と、ローラー荷重との関係は、鋼板の剛性と寸法、張力から求めることができ、ローラー荷重を計測することにより、最大撓み量を推定できる。隣り合う搬送ローラーに掛かる荷重は、その間に供給される冷却水が均等あるいは対称であればほぼ等しくなるため、計測は何れか一方でも良い。冷却水によって鋼板を冷却する領域（冷却ゾーン）が長くそこに多数の搬送ローラーが配置される場合は、一本おきに荷重を計測しても良い。 If the collision force of the cooling water supplied from above the steel plate is large, the load applied to the transport roller increases, and at the same time, the subsidence (deflection) of the steel plate between the transport rollers also increases. The maximum deflection is at the center between two adjacent transport rollers. The relationship between the maximum deflection and the roller load can be determined from the rigidity, dimensions, and tension of the steel sheet, and the roller load must be measured. Thus, the maximum deflection amount can be estimated. Since the load applied to the adjacent transport rollers is substantially equal if the cooling water supplied between them is uniform or symmetric, measurement may be performed either. When the area | region (cooling zone) which cools a steel plate with cooling water is long and many conveyance rollers are arrange | positioned there, you may measure a load every other.
搬送ローラー間にガイドが渡され、例えばそのパスライン（搬送ローラー頂点高さ）からの距離が３０ｍｍであり、鋼板下面とガイドとの接触を回避する場合には、鋼板の最大撓み量３０ｍｍに相当するローラー荷重限界値を予め求めておき、ローラー荷重がその限界値以下となるように上下冷却水噴射圧力を調整すれば良い。鋼板を均一に冷却する目的で、鋼板高さのパスラインからの偏差を所定値以内に抑制する場合も、上下冷却水噴射圧力を同様に調整すれば良い。 When the guide is passed between the transport rollers, for example, when the distance from the pass line (the height of the transport roller apex) is 30 mm, and the contact between the lower surface of the steel plate and the guide is avoided, the maximum deflection amount of the steel plate is equivalent to 30 mm. What is necessary is just to obtain | require the roller load limit value to perform beforehand and to adjust a vertical cooling water injection pressure so that a roller load may become below that limit value. Even when the deviation of the steel plate height from the pass line is suppressed within a predetermined value for the purpose of uniformly cooling the steel plate, the upper and lower cooling water injection pressures may be adjusted similarly.
鋼板の上面に向けて噴射される冷却水の圧力や鋼板の下面に向けて噴射される冷却水の圧力を変更すると、鋼板の上面や下面における冷却能が変化し、上下非対称な冷却となる可能性もあるが、薄鋼板の冷却においては、板厚方向に顕著な温度差が生じることはなく、そもそも大きな問題とはならない。一方、鋼板の組織制御のためには冷却停止温度を適切に制御することが重要であり、上面側の冷却能と下面側の冷却能とを合計した全体の冷却能は目標通りに維持する必要がある。すなわち、ローラー荷重の値が大き過ぎる場合には下面側の冷却水噴射の圧力を高める必要があり、下面側の冷却能を高めた場合に全体の冷却能を維持するために、上面側の冷却能を低減する必要があり、そのために、上面に向けて噴射される冷却水の圧力（噴射圧力）を低くしなければならない。鋼板の上面側に配置されたノズル（上面ノズル）と、鋼板の下面側に配置されたノズル（下面ノズル）とが、鋼板から等距離にあるとは限らず、また、上面ノズルと下面ノズルとでは、ノズル列数や、これらがスプレー形式のノズルである場合にはスプレー広がり角も異なるので、全体の冷却能を一定に保持するための噴射圧の変更量は、上下で一致するとは限らない。よって、冷却装置の構造や冷却の設定条件に応じて予め上下個別に噴射圧と冷却能との関係を求めておき、これを考慮した上下噴射圧の変更制御を行うか、下流側で鋼板温度を監視し、これを一定とする様に上下両方の噴射圧を調整する別の制御を同時に行うことが有効であることに想到した。本発明は、このような知見に基づいて完成させた。 Changing the pressure of the cooling water sprayed toward the upper surface of the steel sheet or the pressure of the cooling water sprayed toward the lower surface of the steel sheet may change the cooling capacity of the upper and lower surfaces of the steel sheet, resulting in asymmetrical upper and lower cooling. However, in cooling a thin steel plate, there is no significant temperature difference in the thickness direction, which is not a big problem in the first place. On the other hand, it is important to control the cooling stop temperature appropriately for the structure control of the steel sheet, and it is necessary to maintain the overall cooling capacity, which is the sum of the cooling capacity on the upper surface side and the cooling capacity on the lower surface side, as intended. There is. That is, when the roller load value is too large, it is necessary to increase the pressure of the cooling water jet on the lower surface side, and in order to maintain the entire cooling capacity when the lower surface cooling capacity is increased, Therefore, it is necessary to reduce the pressure (injection pressure) of the cooling water injected toward the upper surface. The nozzle arranged on the upper surface side of the steel plate (upper surface nozzle) and the nozzle arranged on the lower surface side of the steel plate (lower surface nozzle) are not necessarily equidistant from the steel plate. Then, since the number of nozzle rows and the spray spread angles are different when these are spray type nozzles, the amount of change in the injection pressure for keeping the entire cooling capacity constant does not always match up and down. . Therefore, the relationship between the injection pressure and the cooling capacity is obtained separately in advance according to the structure of the cooling device and the cooling setting conditions, and the change control of the upper and lower injection pressure is performed in consideration of this, or the steel plate temperature is measured on the downstream side. It was conceived that it is effective to simultaneously perform another control for adjusting both the upper and lower injection pressures so as to keep this constant. The present invention has been completed based on such findings.
以下、本発明について説明する。 The present invention will be described below.
本発明の第１の態様は、仕上圧延機と巻取り機との間に位置する鋼板から搬送ローラーへと加えられる荷重を検知する荷重検知部を有する、熱延鋼板の製造設備である。 A first aspect of the present invention is a hot-rolled steel plate manufacturing facility having a load detection unit that detects a load applied from a steel plate located between a finishing mill and a winder to a conveyance roller.
また、上記本発明の第１の態様において、さらに、上記荷重が所定値以下の正値となるように、鋼板の上面並びに下面に向けて噴射される冷却水の量及び／又は噴射圧力を調整する冷却水調整部を有することが好ましい。 Further, in the first aspect of the present invention, the amount and / or injection pressure of the cooling water injected toward the upper surface and the lower surface of the steel plate are further adjusted so that the load becomes a positive value equal to or less than a predetermined value. It is preferable to have a cooling water adjusting unit.
また、冷却水調整部を有する上記本発明の第１の態様において、上記荷重が所定値以下の正値となり、且つ、上記荷重が検知された搬送ローラーと鋼板の搬送方向の上流側に隣接する搬送ローラー、及び、上記荷重が検知された搬送ローラーと搬送方向の下流側に隣接する搬送ローラーの間の区間で鋼板の冷却量が目標通りとなるように、冷却水調整部によって、鋼板の上面並びに下面に向けて噴射される冷却水の量及び／又は噴射圧力が調整されることが好ましい。 Further, in the first aspect of the present invention having the cooling water adjusting unit, the load is a positive value equal to or less than a predetermined value, and is adjacent to the upstream side in the transport direction of the transport roller and the steel plate in which the load is detected. The upper surface of the steel sheet is adjusted by the cooling water adjusting unit so that the cooling amount of the steel sheet becomes a target in the section between the transport roller and the transport roller where the load is detected and the transport roller adjacent to the downstream side in the transport direction. In addition, it is preferable that the amount and / or injection pressure of the cooling water injected toward the lower surface is adjusted.
また、上記本発明の第１の態様において、鋼板へ向けて噴射される冷却水の給水圧力が０．５ＭＰａ以上であり、且つ、鋼板の表面における冷却水の水量密度が１０ｍ３／（ｍ２・ｍｉｎ）以上であることが好ましい。 In the first aspect of the present invention, the supply pressure of the cooling water injected toward the steel plate is 0.5 MPa or more, and the water density of the cooling water on the surface of the steel plate is 10 m 3 / (m 2. -Min) or more is preferable.
本発明の第２の態様は、鋼板の搬送方向上流側から順に配置された、仕上圧延機と、上記本発明の第１の態様にかかる熱延鋼板の冷却装置と、巻取り機とを備える、熱延鋼板の製造装置である。 A second aspect of the present invention includes a finish rolling mill, a hot-rolled steel sheet cooling device according to the first aspect of the present invention, and a winder, which are sequentially arranged from the upstream side in the conveyance direction of the steel sheet. It is a manufacturing apparatus of a hot-rolled steel sheet.
本発明の第３の態様は、上記本発明の第１の態様にかかる熱延鋼板の冷却装置を用いて、仕上圧延機と巻取り機との間に位置する鋼板を冷却する工程を有する、熱延鋼板の製造方法である。 The third aspect of the present invention includes a step of cooling the steel sheet located between the finish rolling mill and the winder using the hot rolled steel sheet cooling device according to the first aspect of the present invention. It is a manufacturing method of a hot-rolled steel sheet.
本発明によれば、荷重検知部によって鋼板から搬送ローラーへと加えられる荷重を検知することができるので、検知した荷重に応じて冷却水の供給形態を制御することにより、高圧且つ大流量の冷却水を衝突させることによって鋼板を急冷する場合であっても、鋼板を安定して走行させることが可能になる。このような冷却水の供給形態制御は、例えば、搬送ローラーへと加えられる荷重が所定値以下の正値となるように、鋼板の上面及び下面へと供給される冷却水の量及び／又は噴射圧力を調整することにより、行うことができる。鋼板を急冷する場合であっても鋼板を安定して走行させることにより、微細結晶粒を有する熱延鋼板を製造しやすくなるので、本発明によれば、微細結晶粒を有する熱延鋼板を製造する際に好適に使用可能な熱延鋼板の冷却装置及び製造装置、並びに、微細結晶粒を有する熱延鋼板を製造することが可能な熱延鋼板の製造方法を提供することができる。 According to the present invention, since the load applied from the steel sheet to the transport roller can be detected by the load detection unit, the cooling water supply mode is controlled according to the detected load, thereby cooling at a high pressure and a large flow rate. Even when the steel sheet is rapidly cooled by colliding with water, the steel sheet can be stably driven. Such cooling water supply form control is performed by, for example, the amount and / or injection of the cooling water supplied to the upper surface and the lower surface of the steel sheet so that the load applied to the transport roller becomes a positive value equal to or less than a predetermined value. This can be done by adjusting the pressure. Even when the steel plate is rapidly cooled, it is easy to produce a hot-rolled steel plate having fine crystal grains by running the steel plate stably. According to the present invention, a hot-rolled steel plate having fine crystal grains is produced. It is possible to provide a method and apparatus for manufacturing a hot-rolled steel sheet capable of producing a hot-rolled steel sheet having fine crystal grains, and a cooling apparatus and a manufacturing apparatus for a hot-rolled steel sheet that can be suitably used for the above.
以下、図面を参照しつつ、本発明の実施の形態について説明する。見やすさのため、図面では繰り返される一部符号の記載を省略することがある。なお、以下に説明する形態は本発明の例示であり、本発明は以下に説明する形態に限定されない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. For ease of viewing, repeated reference numerals may be omitted in the drawings. In addition, the form demonstrated below is an illustration of this invention and this invention is not limited to the form demonstrated below.
図１は、第１実施形態にかかる本発明の熱延鋼板の冷却装置１０（以下において、単に「冷却装置１０」ということがある。）を模式的に示す図である。図１の紙面左側が鋼板１の搬送方向上流側であり、同右側が鋼板１の搬送方向下流側である。図１には、鋼板１の上面側にフラットスプレー（又はフルコーンスプレー）１３、１３、…を、鋼板１の下面側にフラットスプレー（又はフルコーンスプレー）１４、１４、…をそれぞれ使用し、鋼板１を連続冷却するために搬送ローラー１１、１１、…の間隔を広げた例を示しており、ローラー３本分の区間のみを抽出して示している。冷却装置１０は、鋼板１の搬送方向に並列している搬送ローラー１１、１１、…のうち、一部の搬送ローラー１１（図１では、鋼板１の搬送方向に並列している３つの搬送ローラー１１、１１、１１のうち、真ん中に配置されている搬送ローラー１１）に、鋼板１から搬送ローラー１１へと加えられる荷重を検知する荷重計１２が設けられ、冷却水供給部として機能するフラットスプレー１３、１３、…、および、フラットスプレー１４、１４、…（以下において、これらを「スプレー」ということがある。）から鋼板１へ冷却水が供給されることにより、鋼板１が冷却される。冷却装置１０において、スプレーから鋼板１へ向けて供給される冷却水の噴射圧力や給水圧力は、冷却水調整部１５によって決定される。図１には、さらに、搬送ローラー１１、１１、１１の間、且つ、鋼板１の下面側に配置された下面ガイド１６、１６が示されており、鋼板１の上面に滞留水１７が存在する様子が示されている。 FIG. 1 is a diagram schematically illustrating a hot-rolled steel sheet cooling device 10 (hereinafter, simply referred to as “cooling device 10”) according to the first embodiment of the present invention. The left side of FIG. 1 is the upstream side in the conveyance direction of the steel plate 1, and the right side is the downstream side in the conveyance direction of the steel plate 1. In FIG. 1, flat spray (or full cone spray) 13, 13,... Is used on the upper surface side of the steel plate 1, and flat spray (or full cone spray) 14, 14,. The example which expanded the space | interval of the conveyance rollers 11, 11, and ... in order to continuously cool the steel plate 1 is shown, and only the area for three rollers is extracted and shown. The cooling device 10 includes a part of the transport rollers 11, 11,... Parallel to the transport direction of the steel plate 1 (three transport rollers parallel to the transport direction of the steel plate 1 in FIG. 1). 11, 11, 11, a transport roller 11) disposed in the middle is provided with a load meter 12 that detects a load applied from the steel plate 1 to the transport roller 11, and functions as a cooling water supply unit. The steel plate 1 is cooled by supplying cooling water to the steel plate 1 from 13, 13,... And the flat sprays 14, 14,. In the cooling device 10, the cooling water injection pressure and the water supply pressure supplied from the spray toward the steel plate 1 are determined by the cooling water adjusting unit 15. FIG. 1 further shows lower surface guides 16, 16 disposed between the transport rollers 11, 11, 11 and on the lower surface side of the steel plate 1, and stagnant water 17 exists on the upper surface of the steel plate 1. The situation is shown.
このように、搬送ローラー１１、１１、…が等間隔に配置され、スプレーから噴射された冷却水による鋼板１への荷重がその両側の搬送ローラー１１、１１、…に均等に掛かる場合には、中央の搬送ローラー１１のみで荷重を計測し、その値を元に冷却水量や給水圧力を調整すれば良い。スプレーの噴射ノズルを付け替えない限り、あるいは噴射ノズルの数を変えたり噴射ノズルの流路を変更したりする特殊な機能を備えない限り、給水圧力が決まれば冷却水量も決まるため、実際に調整するのは冷却水量又は給水圧力のどちらか一方で良い。図１の例では鋼板上下面を均等に冷却するため、搬送ローラー１１、１１、…の直上にはスプレーを配置していないが、冷却能を増すためにここにスプレーを配置しても良い。荷重計１２によって荷重が計測される搬送ローラー１１の直上にスプレーを配置する場合には、ローラー間における鋼板１の最大撓み量とローラーに加えられた荷重との関係を求める際に、直上に配置したスプレーから供給された冷却水による荷重を考慮しておけば良い。 In this way, when the transport rollers 11, 11,... Are arranged at equal intervals and the load on the steel plate 1 by the cooling water sprayed from the spray is equally applied to the transport rollers 11, 11,. What is necessary is just to measure a load only with the center conveyance roller 11, and to adjust the amount of cooling water and water supply pressure based on the value. Unless the spray nozzle is replaced, or unless there is a special function to change the number of spray nozzles or change the flow path of the spray nozzle, the amount of cooling water will also be determined if the feed water pressure is determined, so it is actually adjusted Either of the cooling water amount or the supply water pressure may be used. In the example of FIG. 1, in order to cool the upper and lower surfaces of the steel plate uniformly, no spray is disposed immediately above the transport rollers 11, 11..., But a spray may be disposed here in order to increase the cooling ability. When the spray is disposed directly above the transport roller 11 where the load is measured by the load meter 12, the spray is disposed directly above when obtaining the relationship between the maximum amount of bending of the steel plate 1 between the rollers and the load applied to the roller. It is sufficient to consider the load due to the cooling water supplied from the spray.
図２は、第２実施形態にかかる本発明の熱延鋼板の冷却装置２０（以下において、単に「冷却装置２０」ということがある。）を模式的に示す図である。図２の紙面左側が鋼板１の搬送方向上流側であり、同右側が鋼板１の搬送方向下流側である。図２には、鋼板１の上面側にパイプラミナースプレー２３、２３、…を、鋼板１の下面側にフルコーンスプレー２４、２４、…を用い、搬送ローラー２１、２１、…は間隔を狭くして鋼板１の走行安定化に配慮している例を示した。冷却装置２０は、鋼板１の搬送方向に並列している搬送ローラー２１、２１、…の一部に、搬送ローラー２１、２１、…へと加えられる荷重を検知する荷重計２２、２２、…が設けられており、荷重計２２が設けられている搬送ローラー２１と、荷重計２２が設けられていない搬送ローラー２１とが、鋼板の搬送方向に交互に配置されている。冷却装置２０では、冷却水供給部として機能するパイプラミナースプレー２３、２３、…、および、フルコーンスプレー２４、２４、…（以下において、これらを「スプレー」ということがある。）から鋼板１へ冷却水が供給されることにより、鋼板１が冷却される。冷却装置２０において、スプレーから鋼板１へ向けて供給される冷却水の噴射圧力や給水圧力は、冷却水調整部２５によって決定される。図２には、さらに、鋼板１の上面に滞留水２６が存在する様子が示されている。 FIG. 2 is a diagram schematically illustrating a hot-rolled steel sheet cooling device 20 according to the second embodiment (hereinafter, simply referred to as “cooling device 20”). The left side of FIG. 2 is the upstream side in the conveyance direction of the steel plate 1, and the right side is the downstream side in the conveyance direction of the steel plate 1. In FIG. 2, pipe laminar sprays 23, 23,... Are used on the upper surface side of the steel plate 1, and full cone sprays 24, 24,... Are used on the lower surface side of the steel plate 1, and the conveying rollers 21, 21,. Thus, an example in which traveling stability of the steel plate 1 is taken into consideration is shown. The cooling device 20 includes load meters 22, 22,... That detect loads applied to the transport rollers 21, 21,... On a part of the transport rollers 21, 21,. The conveying roller 21 provided with the load meter 22 and the conveying roller 21 not provided with the load meter 22 are alternately arranged in the conveying direction of the steel plate. In the cooling device 20, the pipe laminar sprays 23, 23,... And the full cone sprays 24, 24,... (Which may be referred to as “sprays” hereinafter) function as a cooling water supply unit. The steel sheet 1 is cooled by supplying the cooling water. In the cooling device 20, the injection pressure and the supply water pressure of the cooling water supplied from the spray toward the steel plate 1 are determined by the cooling water adjusting unit 25. FIG. 2 further shows a state in which the accumulated water 26 exists on the upper surface of the steel plate 1.
冷却装置２０でも、冷却能力を上げるためにスプレーから噴射された水が鋼板１に衝突する際の衝突力を高めたり、上面の滞留水２６が増大したりすれば、鋼板１の走行が不安定になるため、本発明の適用対象となる。なお、図２には、荷重計２２が設けられている搬送ローラー２１と、荷重計２２が設けられていない搬送ローラー２１とが、鋼板の搬送方向に交互に配置されている様子を示したが、本発明の冷却装置はこの形態に限定されない。なお、一般に、冷却温度を制御するためにスプレー（スプレーが接続されているヘッダー）を選択的に使用する場合があるが、ヘッダーを選択的に使用する場合には、想定される使用パターンを考慮した上で必要な箇所に荷重計２２、２２、…を配置し、荷重を計測すれば良い。 Even in the cooling device 20, if the collision force when the water sprayed from the spray collides with the steel plate 1 to increase the cooling capacity or the accumulated water 26 on the upper surface increases, the running of the steel plate 1 becomes unstable. Therefore, the present invention is applied. FIG. 2 shows a state in which the transport roller 21 provided with the load meter 22 and the transport roller 21 not provided with the load meter 22 are alternately arranged in the steel plate transport direction. The cooling device of the present invention is not limited to this form. In general, a spray (a header to which a spray is connected) may be selectively used to control the cooling temperature. However, when a header is selectively used, an assumed usage pattern is considered. Then, load meters 22, 22,... May be arranged at necessary places to measure the load.
図３は、本発明の冷却装置１０を有する熱延鋼板の製造装置１００を模式的に示す図である。図３では、仕上圧延機列２、巻取り機３、および、冷却装置１０以外の機器の記載を省略している。熱延鋼板の製造装置１００は、仕上圧延機列２と巻取り機３とを有し、これらの間に冷却装置１０が配置されている。本発明の冷却装置１０によれば、高圧且つ大流量の冷却水を衝突させることによって鋼板を急冷する場合であっても、鋼板を安定して走行させることが可能なので、仕上圧延機列２による仕上圧延の終了直後に冷却装置１０を用いて鋼板を急冷する場合であっても、鋼板を安定して走行させることができる。鋼板を安定して走行させることにより、鋼板を均一に冷却することが可能になるので、本発明によれば、微細結晶粒を有する熱延鋼板を製造することが可能な、熱延鋼板の製造装置１００を提供することができる。なお、ここでは冷却装置１０を有する熱延鋼板の製造装置１００を例示したが、本発明の熱延鋼板の製造装置は当該形態に限定されず、例えば、仕上圧延機と巻取り機との間に、冷却装置２０が配置された形態とすることも可能である。 FIG. 3 is a diagram schematically showing a hot-rolled steel sheet manufacturing apparatus 100 having the cooling apparatus 10 of the present invention. In FIG. 3, description of equipment other than the finish rolling mill row 2, the winder 3, and the cooling device 10 is omitted. The hot-rolled steel sheet manufacturing apparatus 100 includes a finish rolling mill row 2 and a winder 3, and a cooling device 10 is disposed between them. According to the cooling device 10 of the present invention, even when the steel plate is rapidly cooled by colliding with high-pressure and high-flow-rate cooling water, the steel plate can be traveled stably. Even when the steel sheet is rapidly cooled using the cooling device 10 immediately after finishing rolling, the steel sheet can be stably run. Since the steel plate can be cooled uniformly by running the steel plate stably, according to the present invention, it is possible to produce a hot-rolled steel plate having fine crystal grains. An apparatus 100 can be provided. In addition, although the manufacturing apparatus 100 of the hot-rolled steel sheet which has the cooling device 10 was illustrated here, the manufacturing apparatus of the hot-rolled steel sheet of this invention is not limited to the said form, For example, between a finishing rolling mill and a winder. In addition, a configuration in which the cooling device 20 is arranged is also possible.
図４は、本発明の作用を検証するために行った実験室用の装置を模式的に示す図である。隣接する搬送ローラーの間隔を１．９ｍとし、フラットスプレーノズルを備えたヘッダーを、銅板の上面側および下面側にそれぞれ９本ずつ配置した。銅板に張力を負荷した状態で両搬送ローラーに接するように静止させておき、上面側に配置したヘッダー（上ヘッダー）および下面側に配置したヘッダー（下ヘッダー）の給水圧を変更しながら冷却水を噴射し、片側の搬送ローラーで計測した荷重と銅板の撓み量との関係を調査した。室温での静的な試験のため銅板の撓みは接触式変位計で計測できる。銅を用いたのは、板の剛性を熱間の鋼に近づけるためである。その結果を図５乃至図７に示す。例えば、パスラインよりも下側に撓んだ場合に負の値で表す撓み量として−１０ｍｍから０ｍｍまでが適正範囲だとすれば、これに相当するローラー荷重は０．２ｋＮから１．９ｋＮの範囲だということが分かり、ローラー荷重をこの範囲に調整するには、上下ヘッダーの給水圧力差（上−下）を−０．０８ＭＰａから０．１ＭＰａの範囲内に調整すれば良いことが分かる。 FIG. 4 is a diagram schematically showing a laboratory apparatus used for verifying the operation of the present invention. The interval between adjacent transport rollers was set to 1.9 m, and nine headers equipped with flat spray nozzles were arranged on each of the upper surface side and the lower surface side of the copper plate. Cooling water while changing the feed water pressure of the header (upper header) placed on the upper surface side and the header (lower header) placed on the lower surface side while keeping the copper plate under tension so as to contact both transport rollers The relationship between the load measured by the conveyance roller on one side and the bending amount of the copper plate was investigated. The copper plate deflection can be measured with a contact displacement meter for static testing at room temperature. The reason for using copper is to make the rigidity of the plate closer to that of hot steel. The results are shown in FIGS. For example, if the appropriate range is from −10 mm to 0 mm as the amount of deflection expressed as a negative value when deflected below the pass line, the corresponding roller load is 0.2 kN to 1.9 kN. It turns out that it is a range, and in order to adjust a roller load to this range, it turns out that what is necessary is just to adjust the water supply pressure difference (upper-lower) of an upper and lower header in the range of -0.08MPa to 0.1MPa.
実際に冷却を行う場合には、冷却能が所定の値となるように、給水圧力を調整する必要も生じるが、走行安定性が確保される範囲で上下どちらか片側の給水圧力を増減させても良いし、対になる上下のヘッダーの給水圧力差を固定したまま上下給水圧力の平均値（あるいは、上下給水圧力の鋼板進行方向の積分値）を変更しても良い。図４の事例では上下に同じ仕様のフラットスプレーを用いているため、上下給水圧力の平均値を一定に保っておけば、個々の対になる上下のヘッダーの給水圧力差を変更しても全体の冷却能はほとんど変化しない。 When actually cooling, it may be necessary to adjust the water supply pressure so that the cooling capacity becomes a predetermined value, but the water supply pressure on either one of the upper and lower sides can be increased or decreased within the range that ensures running stability. Alternatively, the average value of the upper and lower water supply pressures (or the integral value of the upper and lower water supply pressures in the direction of travel of the steel sheet) may be changed while fixing the difference between the water supply pressures of the upper and lower headers. In the case of Fig. 4, flat sprays with the same specifications are used for the upper and lower sides, so if the average value of the upper and lower water supply pressures is kept constant, the overall difference can be achieved even if the water supply pressure difference between the upper and lower headers is changed. The cooling capacity of the battery hardly changes.
以下、実施例を参照しつつ、本発明についてさらに説明する。 The present invention will be further described below with reference to examples.
冷却装置１０に相当する急冷装置を用いて鋼板を冷却した場合（本発明例）、および、荷重検知部を有しない従来の冷却装置を用いて鋼板を冷却した場合（比較例）のそれぞれについて、鋼板を実際に冷却することにより、鋼板の走行安定性および冷却むらの発生状況を調査した。
本発明例および比較例ともに、隣接するローラーの間隔は１．９ｍとし、隣接するローラーの間には、上下各９本のヘッダーを配置した。ヘッダーには、給水圧力が１．５ＭＰａのときに２００Ｌ／ｍｉｎ（上面側）、および、１８０Ｌ／ｍｉｎ（下面側）の水を噴射するフラットスプレーノズルを板幅方向に６０ｍｍ間隔で設置した。個々のヘッダーに給水圧力調整機構が備えられ０．０５ＭＰａ以下の精度で制御可能であり、上面側および下面側のそれぞれで給水圧力が一様となるように制御した。
冷却される鋼板の大きさは、板厚２ｍｍ、板幅２４００ｍｍ、１６００ｍｍとし、これを毎分１２００ｍの速さで通し、８５０℃から６５０℃までの２００℃降下（冷却量１００％）とした冷却を行った。なお、事前の調査により、板幅が１２４０ｍｍの場合には、ローラー荷重が０．２ｋＮ以上２．０ｋＮ以下の範囲にあれば、鋼板の撓みが−１０ｍｍから０ｍｍの範囲におさまり、鋼板の安定走行および均一冷却が可能であることが分かっている。
About each of the case where a steel plate is cooled using a quenching device corresponding to the cooling device 10 (example of the present invention), and the case where a steel plate is cooled using a conventional cooling device that does not have a load detection unit (comparative example), By actually cooling the steel sheet, the running stability of the steel sheet and the occurrence of uneven cooling were investigated.
In both the inventive example and the comparative example, the interval between adjacent rollers was 1.9 m, and nine headers were arranged between the adjacent rollers. In the header, flat spray nozzles that inject 200 L / min (upper surface side) and 180 L / min (lower surface side) of water at a water supply pressure of 1.5 MPa were installed at intervals of 60 mm in the plate width direction. Each header is provided with a feed water pressure adjusting mechanism and can be controlled with an accuracy of 0.05 MPa or less, and the feed water pressure is controlled to be uniform on each of the upper surface side and the lower surface side.
The size of the steel plate to be cooled is 2 mm thick, 2400 mm wide, 1600 mm wide, and this is passed at a speed of 1200 m / min, and the cooling is 200 ° C. from 850 ° C. to 650 ° C. (cooling amount 100%). Went. In addition, when the plate width is 1240 mm as a result of prior investigation, if the roller load is in the range of 0.2 kN or more and 2.0 kN or less, the bending of the steel plate is within the range of −10 mm to 0 mm, and the stable running of the steel plate And it has been found that uniform cooling is possible.
本発明例および比較例の冷却条件を表１に、本発明例および比較例の結果を表２に、それぞれ示す。なお、本発明例の急冷装置および比較例の冷却装置は、ロードセル（荷重検知部）の設置有無を除き、同様の機能を有している。 Table 1 shows the cooling conditions of the inventive examples and comparative examples, and Table 2 shows the results of the inventive examples and comparative examples. The rapid cooling device of the present invention example and the cooling device of the comparative example have the same functions except for the presence or absence of a load cell (load detection unit).
条件Ｎｏ．１は従来方式の冷却装置を用いた例（比較例）である。全ヘッダーから給水圧１．５ＭＰａで冷却水を噴射したところ、鋼板がローラー間で下方に大きく撓み、下面ガイドに接触した結果、下面にスリ疵を生じると共に冷却むらが生じた。これに対処するため、条件Ｎｏ．２（比較例）では上面側の給水圧を１．１ＭＰａまで低下させたところ、今度は鋼板が浮き上がってしまい走行が不安定となると共に冷却量も９５％まで低下してしまった。 Condition No. 1 is an example (comparative example) using a conventional cooling device. When cooling water was jetted from all the headers at a water supply pressure of 1.5 MPa, the steel plate was greatly bent downward between the rollers, and as a result of contacting the lower surface guide, there was a crack on the lower surface and uneven cooling. In order to deal with this, the condition No. In No. 2 (Comparative Example), when the water supply pressure on the upper surface side was lowered to 1.1 MPa, the steel sheet was lifted up, the running became unstable, and the cooling amount was lowered to 95%.
条件Ｎｏ．３は本発明例である。ロードセルで測定したローラー荷重が０．２ｋＮ以上２．０ｋＮ未満の範囲になるように、上下の給水圧を調整した結果、上面側の給水圧を１．１５ＭＰａとし、且つ、下面側の給水圧を１．４５ＭＰａとすることでローラー荷重が０．８７ＭＰａとなり、鋼板を安定走行させることができた。但し、そのままでは冷却量が９５％であったため、条件Ｎｏ．４（本発明例）では、さらに冷却量の制御も併用した。その結果、上面側の給水圧を１．３５ＭＰａとし、且つ、下面側の給水圧を１．６５ＭＰａとすることでローラー荷重が１．４５ＭＰａとなり、冷却量が１００％になって目的の冷却を行うことができた。 Condition No. 3 is an example of the present invention. As a result of adjusting the upper and lower water supply pressures so that the roller load measured by the load cell is in the range of 0.2 kN or more and less than 2.0 kN, the upper surface water supply pressure is 1.15 MPa, and the lower surface water supply pressure is By setting the pressure to 1.45 MPa, the roller load was 0.87 MPa, and the steel sheet could be stably run. However, since the cooling amount was 95% as it is, the condition No. In No. 4 (invention example), the cooling amount was also controlled. As a result, by setting the water supply pressure on the upper surface side to 1.35 MPa and the water supply pressure on the lower surface side to 1.65 MPa, the roller load becomes 1.45 MPa, the cooling amount becomes 100%, and the target cooling is performed. I was able to.
条件Ｎｏ．５は板幅が１６００ｍｍと広くなった場合（本発明例）である。事前調査の結果がない鋼板を冷却する場合には、ローラー荷重の適正範囲を板幅分だけ補正して判別、制御すれば良い。条件Ｎｏ．５のローラー荷重１．８６ｋＮは、条件Ｎｏ．４のローラー荷重１．４５ｋＮと等価な状態を示しており、鋼板走行状況および冷却むら発生状況の結果も、条件Ｎｏ．４と同じであった。 Condition No. 5 is the case where the plate width is as wide as 1600 mm (example of the present invention). In the case of cooling a steel plate that has not been subjected to a preliminary investigation, it is only necessary to correct and determine and control the appropriate range of roller load by the plate width. Condition No. No. 5 roller load 1.86 kN 4 shows a state equivalent to a roller load of 1.45 kN. It was the same as 4.
条件Ｎｏ．６は条件Ｎｏ．４において上面側に配置したヘッダーの中の２本が故障で不使用となった状況である。表２に示したように、本発明を適用しない条件Ｎｏ．６（比較例）では、上下のスプレー衝突圧のバランスが崩れ、鋼板が浮き上がって走行が不安定になるとともに、冷却むらも発生した。また、当然ながらヘッダー２本分の冷却量不足も生じた。これに対し、ロードセルで測定したローラー荷重が０．２ｋＮ以上２．０ｋＮ未満の範囲になるように、上下の給水圧を調整した条件Ｎｏ．７（本発明例）では、上面側の給水圧を１．８０ＭＰａとし、且つ、下面側の給水圧を１．８０ＭＰａとすることでローラー荷重が１．５０ＭＰａとなり、鋼板を安定走行させつつ正常な冷却を実施できた。 Condition No. 6 is condition No. In FIG. 4, two of the headers arranged on the upper surface side are not used due to a failure. As shown in Table 2, condition no. In No. 6 (Comparative Example), the balance between the upper and lower spray collision pressures was lost, the steel sheet was lifted, running was unstable, and cooling unevenness also occurred. Of course, the cooling amount for two headers was insufficient. On the other hand, Condition No. in which the upper and lower water supply pressures were adjusted so that the roller load measured by the load cell was in the range of 0.2 kN or more and less than 2.0 kN. 7 (example of the present invention), the water supply pressure on the upper surface side is 1.80 MPa, and the water supply pressure on the lower surface side is 1.80 MPa. Cooling could be carried out.
以上説明したように、仕上圧延機と巻取り機との間に位置する鋼板から搬送ローラーへと加えられる荷重を検知する荷重検知部を有する本発明の冷却装置によれば、検知された荷重に応じて冷却水の供給形態を制御することにより、１．０ＭＰａを超える圧力で給水された冷却水によって鋼板を急冷する場合であっても、鋼板を安定して走行させることが可能である。そして、鋼板を安定して走行させることが可能になる結果、鋼板を均一に冷却することが可能になる。したがって、本発明によれば、微細結晶粒を有する鋼板などの圧延後に急速冷却を要する鋼板を製造する際にも使用可能な、熱延鋼板の冷却装置を提供することができる。そして、このような効果を奏する冷却装置を、熱延鋼板の製造装置の仕上圧延機と巻取り機との間に配置することにより、微細結晶粒を有する鋼板などの圧延後に急速冷却を要する鋼板を製造する際にも使用可能な、熱延鋼板の製造装置を提供することができる。さらに、例えば、仕上圧延を行ってから、本発明の熱延鋼板の冷却装置を用いて、仕上圧延機と巻取り機との間に位置する鋼板を冷却し、その後、冷却された鋼板を巻取り機で巻き取る形態とすることにより、微細結晶粒を有する鋼板などの圧延後に急速冷却を要する鋼板を製造することが可能な、熱延鋼板の製造方法を提供することができる。 As described above, according to the cooling device of the present invention having the load detection unit that detects the load applied to the conveying roller from the steel plate located between the finish rolling mill and the winder, the detected load By controlling the supply form of the cooling water accordingly, the steel sheet can be stably driven even when the steel sheet is rapidly cooled by the cooling water supplied at a pressure exceeding 1.0 MPa. And as a result of being able to run a steel plate stably, it becomes possible to cool a steel plate uniformly. Therefore, according to this invention, the cooling apparatus of a hot-rolled steel plate which can be used also when manufacturing the steel plate which requires rapid cooling after rolling, such as a steel plate which has a fine crystal grain, can be provided. And the steel plate which requires rapid cooling after rolling of the steel plate etc. which have a fine crystal grain by arrange | positioning the cooling device which has such an effect between the finishing mill of a manufacturing apparatus of a hot-rolled steel plate, and a winder It is possible to provide a hot-rolled steel sheet manufacturing apparatus that can be used when manufacturing the steel sheet. Further, for example, after performing finish rolling, the steel sheet located between the finish rolling mill and the winder is cooled using the hot-rolled steel sheet cooling apparatus of the present invention, and then the cooled steel sheet is wound. By making it the form wound up with a take-off machine, the manufacturing method of a hot-rolled steel plate which can manufacture the steel plate which requires rapid cooling after rolling, such as a steel plate which has a fine crystal grain, can be provided.
本発明の熱延鋼板の冷却装置、熱延鋼板の製造装置、及び、熱延鋼板の製造方法は、微細結晶粒を有する鋼板などの圧延後に急速冷却を要する鋼板の製造に用いることができる。また、微細結晶粒を有する熱延鋼板は、自動車用、家電用、機械構造用、建築用等の用途に使用される素材として用いることができる。 The apparatus for cooling a hot-rolled steel sheet, the apparatus for manufacturing a hot-rolled steel sheet, and the method for manufacturing a hot-rolled steel sheet according to the present invention can be used for manufacturing a steel sheet that requires rapid cooling after rolling, such as a steel sheet having fine crystal grains. Moreover, the hot-rolled steel sheet having fine crystal grains can be used as a material used for applications such as automobiles, household appliances, machine structures, and buildings.
１…鋼板
２…仕上圧延機列
３…巻取り機
１０、２０…熱延鋼板の冷却装置
１１、２１…搬送ローラー
１２、２２…荷重計（荷重検知部）
１３、１４…フラットスプレー（冷却水供給部）
１５、２５…冷却水調整部
１６…下面ガイド
１７、２６…滞留水
２３…パイプラミナースプレー（冷却水供給部）
２４…フルコーンスプレー（冷却水供給部）
１００…熱延鋼板の製造装置
DESCRIPTION OF SYMBOLS 1 ... Steel plate 2 ... Finish rolling mill row 3 ... Winding machine 10, 20 ... Cooling device of hot-rolled steel plate 11, 21 ... Conveyance roller 12, 22 ... Load meter (load detection part)
13, 14 ... Flat spray (cooling water supply part)
15, 25 ... Cooling water adjustment unit 16 ... Lower surface guide 17, 26 ... Retained water 23 ... Pipe laminar spray (cooling water supply unit)
24 ... Full cone spray (cooling water supply unit)
100 ... Hot rolled steel plate manufacturing equipment
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| CN110805096A (en) * | 2019-11-22 | 2020-02-18 | 东北大学 | Variable-frequency water supply control method for heat treatment of metal plate strip |
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| JP5946380B2 (en) | 2016-07-06 |
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