JPH09103817A - Manufacture of hot rolled steel sheet - Google Patents
Manufacture of hot rolled steel sheetInfo
- Publication number
- JPH09103817A JPH09103817A JP25981295A JP25981295A JPH09103817A JP H09103817 A JPH09103817 A JP H09103817A JP 25981295 A JP25981295 A JP 25981295A JP 25981295 A JP25981295 A JP 25981295A JP H09103817 A JPH09103817 A JP H09103817A
- Authority
- JP
- Japan
- Prior art keywords
- scale
- rolling
- descaling
- steel
- steel sheet
- 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.)
- Withdrawn
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- Metal Rolling (AREA)
Abstract
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、熱間圧延時に鋼材
表面に高圧水ジェットを噴射してデスケーリングを行
い、スケール疵やスケール模様の発生を防止し、表面性
状の優れた熱延鋼板を製造する方法に関する。TECHNICAL FIELD The present invention relates to a hot-rolled steel sheet having excellent surface properties, which is produced by jetting a high-pressure water jet to the surface of a steel material during hot rolling for descaling to prevent the occurrence of scale flaws and scale patterns. It relates to a method of manufacturing.
【０００２】[0002]
【従来技術】鋼板の製造に当たっては、素材のスラブを
酸化性雰囲気の加熱炉により、通常１１００〜１３００
℃の温度で数時間加熱し、ついでホットストリップミル
にて熱間圧延されるのが一般的であるが、この際、スラ
ブ表面に生成したスケールが充分に除去されない状態の
まゝで鋼材が圧延されると、スケールが成品の表面に押
し込まれ、スケール疵やスケール模様として残る。2. Description of the Related Art In the production of a steel sheet, a slab of a raw material is usually heated in a heating furnace in an oxidizing atmosphere in a range of 1100 to 1300.
Generally, it is heated at a temperature of ℃ for several hours and then hot-rolled in a hot strip mill.At this time, the steel material is rolled until the scale generated on the slab surface is not sufficiently removed. Then, the scale is pushed into the surface of the product and remains as a scale flaw or a scale pattern.
【０００３】このようなスケール疵やスケール模様は、
圧延後の成品（黒皮成品）の外観を悪化させるのみなら
ず、酸洗によりスケールを除去した後の成品（白皮成
品）の表面に凹凸状の欠陥を残存させる原因となり、ま
た曲げ加工時のクラックの起点となったり、熱間圧延工
程内の鋼板強制冷却時に、スケール残存部と剥離部の冷
却能の差により、材質の機械的特性値にムラが発生する
等鋼板の品質に重大な悪影響を及ぼすものである。Such scale flaws and scale patterns are
Not only does the appearance of the rolled product (black leather product) deteriorate, but it also causes uneven defects to remain on the surface of the product (white leather product) after removing the scale by pickling, and during bending. It becomes a starting point of cracks, and during forced cooling of the steel plate in the hot rolling process, the difference in the cooling capacity between the scale remaining part and the peeling part causes unevenness in the mechanical property values of the material. It has an adverse effect.
【０００４】通常このようなスケール疵の発生を防止す
るための方法としては、圧延ラインに１００〜１５０kg
f/cm2 の吐出圧力の水ジェットによるデスケーリング装
置を設置し、これによって鋼材表面のスケールを剥離し
除去した後に圧延を行う方法がとられている。しかしな
がらスケールの剥離性の良否は、スケールの組成及び構
造によって大きく左右され、特にＳｉ含有量の多い鋼
（以下、高Ｓｉ鋼という）やＮｉを多く含む鋼のスケー
ルの場合、著しく剥離性が悪くなることが知られてい
る。Generally, a method for preventing the occurrence of such scale flaws is 100 to 150 kg on a rolling line.
A method is used in which a descaling device using a water jet with a discharge pressure of f / cm 2 is installed, and the scale on the steel material surface is peeled off and removed, and then rolling is performed. However, the quality of the peelability of the scale is greatly influenced by the composition and structure of the scale, and particularly in the case of a steel scale having a high Si content (hereinafter referred to as high Si steel) or a steel scale containing a large amount of Ni, the peelability is significantly poor. Is known to be.
【０００５】この原因は、高温酸化に際して鋼中のＳｉ
が選択酸化されてＦｅＯ（ウスタイト）と地鉄の界面に
２ＦｅＯ・ＳｉＯ2 （ファイアライト）が形成され、こ
れが低融点（１１７０℃）のため溶融状態となり、スケ
ールと地鉄中に楔状に侵入するため、スケールと地鉄界
面が複雑に入り組んだ特有構造のスケール層が形成され
るためである。また鋼中にＮｉを含む場合は、酸化が進
行するとＮｉの濃化部が凸状として残存し、界面形状が
凹凸となる。そのためスケールの剥離性が悪くなる。[0005] This is because the Si in the steel during high-temperature oxidation is
Is selectively oxidized to form 2FeO.SiO 2 (firelite) at the interface between FeO (wustite) and the base iron, which is in a molten state due to its low melting point (1170 ° C.) and penetrates into the scale and the base iron in a wedge shape. Therefore, a scale layer having a unique structure in which the scale and the ground iron interface are complicatedly formed is formed. When the steel contains Ni, as the oxidation progresses, the concentrated portion of Ni remains as a convex shape and the interface shape becomes uneven. Therefore, the peelability of the scale becomes poor.
【０００６】このような悪影響は、鋼の化学組成に依存
するものであるが、特にＳｉの影響が大きく、Ｓｉ含有
量が０．２％以上の場合に著しく増大し、この範囲の鋼
を熱間圧延する場合には、スケール疵の発生を完全に防
止することは極めて困難であった。これを改善する手段
としては、例えば加熱温度をファイアライト溶融点（１
１７０℃）以下とする方法や、加熱前のスラブ面にスケ
ールを改質し、剥離性を向上させるための薬剤を塗布す
る方法（特開昭５７−６４９３号）、ブラシロールを使
用して機械的にスケールを剥離させる方法（特開昭５９
−１３９２６号）などが提案されているが、いづれも繁
雑で作業性に劣る、製造コストの面で問題がある、温度
低下により仕上圧延が制約される等の問題があり、いづ
れもスケール疵を防止する抜本的な対策とはなっていな
い。[0006] Such an adverse effect depends on the chemical composition of the steel. Particularly, the influence of Si is large, and is significantly increased when the Si content is 0.2% or more. In the case of cold rolling, it was extremely difficult to completely prevent the occurrence of scale flaws. As a means for improving this, for example, the heating temperature is set to the melting point of the firelite (1).
170 ° C.) or less, a method of modifying the scale on the slab surface before heating and applying a chemical agent for improving peelability (JP-A-57-6493), a machine using a brush roll. Method for peeling off the scale manually
No. -13926) has been proposed, but there are problems that they are complicated and inferior in workability, there is a problem in terms of manufacturing cost, and finish rolling is restricted due to temperature decrease. It is not a drastic measure to prevent it.
【０００７】[0007]
【発明が解決しようとする課題】本発明は、上記の問題
を解消することを目的としてなされたもので、デスケー
リングを最適な条件で実施することにより、スケール疵
がなく、表面性状が良好な熱延鋼板を製造する方法を提
供しようとするものである。DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and by performing descaling under optimal conditions, there are no scale flaws and good surface properties. An object of the present invention is to provide a method for manufacturing a hot-rolled steel sheet.
【０００８】[0008]
【課題の解決手段】本発明者らは、熱間圧延時の鋼材表
面に生成するスケールのデスケーリングによる剥離性を
向上させるには、鋼材の地鉄界面にポアを集中させるこ
とが重要であると考え、ポアの形成要因として最終粗圧
延を終えて仕上圧延前のスケールブレーカー（以下「Ｆ
ＳＢ」という）に至るまでのスラブの経過時間に着目
し、この経過時間とポアの関連について調査した。その
結果、スラブの全長が最終粗圧延を終えて粗圧延機から
送り出されたのち、ＦＳＢを通過するまでの経過時間が
３０秒以下ではポアの生成量が少なく、デスケーリング
後のスケール剥離性が低下し、スケールが残存するこ
と、上記経過時間が３００秒以上では、スケール層が厚
くなって却ってスケール剥離性が悪くなるほか、生産性
が著しく低下したり、鋼材の温度低下が大きくなるた
め、圧延性、通板性の悪化も引き起こす等の不具合を生
ずることを見出し、これより上記経過時間は３０〜３０
０秒、好ましくは５０〜１２０秒とするとよいことが分
かった。Means for Solving the Problems It is important for the present inventors to concentrate pores at the base metal interface of a steel material in order to improve the peeling property due to descaling of the scale generated on the surface of the steel material during hot rolling. As a factor for forming pores, a scale breaker after final rough rolling and before finish rolling (hereinafter referred to as “F
Focusing on the elapsed time of the slab before reaching "SB"), the relationship between this elapsed time and the pore was investigated. As a result, after the final rough rolling of the slab has been completed and after being sent from the rough rolling mill, the amount of pores generated is small when the elapsed time before passing through the FSB is 30 seconds or less, and the scale peeling property after descaling is small. If the scale is decreased and the scale remains, and if the elapsed time is 300 seconds or more, the scale layer becomes thick and the scale peeling property is rather deteriorated, and the productivity is significantly decreased, and the temperature decrease of the steel material is increased, It was found that problems such as deterioration of rollability and stripability occur, and the elapsed time is 30 to 30.
It has been found that it is good to set it to 0 second, preferably 50 to 120 seconds.
【０００９】本発明者らはまた、ＦＳＢでの吐出圧力と
スケール剥離性についても調査したところ、吐出圧力を
２５０kgf/cm2 以上にすると、Ｓｉ、Ｎｉを０．２％以
上含むＳｉ含有鋼やＮｉ含有鋼等の難スケール剥離材で
あっても、スケールをほゞ剥離できることを見出した。
すなわち表１に示すような組成の鋼材Ａ、Ｂ及びＣにつ
いて、デスケーリング吐出圧力と圧延後の製品における
スケール残存率との関係を調査した結果、図２に示すよ
うに、鋼材Ａ、Ｂ及びＣ共、デスケーリングの吐出圧力
が２５０kgf/cm 2 以下では、単位面積当たりのスケール
残存率が大きくなるが、吐出圧力が２５０kgf/cm2 を越
えると、スケール残存率はほゞ１％未満となることを見
出した。The present inventors also set the discharge pressure at the FSB and
When the scale peelability was also investigated, the discharge pressure was
250kgf / cmTwoWith the above, Si and Ni should be 0.2% or less.
For difficult-scale peeling materials such as Si-containing steel and Ni-containing steel
It was found that even if there is, the scale can be almost peeled off.
That is, for steel materials A, B and C having the compositions shown in Table 1,
The descaling discharge pressure and the product after rolling
As a result of investigating the relationship with the scale residual rate, it is shown in Fig. 2.
Descaling discharge pressure for steel materials A, B and C
Is 250 kgf / cm TwoBelow is the scale per unit area
The discharge rate is 250kgf / cm although the residual rate becomes large.TwoOver
If you look at it, you can see that the scale survival rate is less than 1%.
Issued.
【００１０】第１の発明は、上記の知見に基づいて創案
されたもので、スラブの全長が最終粗圧延を終えて粗圧
延機から送り出されたのち、ＦＳＢを通過するまでの経
過時間が３０〜３００秒、好ましくは５０〜１２０秒で
あり、ＦＳＢより噴射する吐出圧力２５０〜６００kgf/
cm2 の高圧水ジェットによりデスケーリングすることを
特徴とする。The first invention was devised based on the above findings, and the elapsed time from the completion of the final rough rolling of the slab after being sent out from the rough rolling mill to the passage of the FSB is 30 times. ~ 300 seconds, preferably 50-120 seconds, the discharge pressure from the FSB is 250-600 kgf /
It is characterized by descaling by a high-pressure water jet of cm 2 .
【００１１】ここで、吐出圧力の下限を２５０kgf/cm2
としたのは、これ以下では上述するように、スケール残
存率が大きくなって製品価値が著しく損なわれるためで
あるが、上限を６００kgf/cm2 以下としたのは、圧延後
の製品のスケール残存率は低減できても、ポンプの高圧
化に伴うモータの大型化やヘッダー、配管の肉厚増加等
の設備、コスト面の問題が非常に大きくなるためであ
る。Here, the lower limit of the discharge pressure is 250 kgf / cm 2
The reason for this is that, as described below, the scale remaining rate becomes large and the product value is significantly impaired, but the upper limit of 600 kgf / cm 2 or less is the scale remaining of the product after rolling. This is because, although the rate can be reduced, the problem of equipment and cost, such as an increase in the size of the motor and an increase in the wall thickness of the header and the piping, becomes very large due to the high pressure of the pump.
【００１２】Ｓｉ含有鋼は、Ｓｉの含有量が０．２％以
上になると、加熱時のスケールや二次スケール中にファ
イアライトが地鉄界面に深く侵入し、スケール剥離は困
難を極め、またＮｉ含有鋼もＮｉ含有量が０．２％を越
えると、地鉄界面の凹凸が激しくなり、スケール剥離性
が困難となるが、本発明は、上述の鋼材Ａ、Ｂ及びＣの
ように、Ｓｉ及びＮｉ含有量がそれぞれ０．２％以上あ
るような鋼材に対しても十分なスケール剥離効果があ
る。In Si-containing steel, when the Si content is 0.2% or more, firelite penetrates deeply into the base metal interface in the scale and secondary scale during heating, and scale peeling becomes extremely difficult. When the Ni content of the Ni-containing steel exceeds 0.2%, the unevenness of the base iron interface becomes severe and the scale releasability becomes difficult. However, according to the present invention, like the steel materials A, B and C described above, A sufficient scale peeling effect is obtained even for steel materials having Si and Ni contents of 0.2% or more.
【００１３】したがって第２の発明は、上記発明のデス
ケーリングをＳｉ含有量が０．２〜２．０％の鋼材に実
施したことを特徴とし、第３の発明は、上記発明のデス
ケーリングをＮｉ含有量が０．２〜２．０％の鋼材に対
して実施することを特徴とする。Ｓｉの含有量は０．２
％以上になると、加熱時のスケールや二次スケール中に
ファイアライトが生成するため、そのファイアライトが
地鉄界面に深く侵入し、スケール剥離は困難を極める。
本発明方法によると、このようにスケール剥離が困難な
Ｓｉを０．２％以上含有する鋼板に対し、より効果的な
デスケールが可能である。上限は本来限定する必要はな
いが、溶接性、冷間加工性が悪化するため、Ｓｉ含有量
を２．０％以下に限定した。一方、Ｎｉは０．２％を越
えると地鉄界面の凹凸が著しくなり、スケール剥離が困
難となる。本発明法によると、このような鋼板に対し、
より効果的にデスケールが可能となる。上限は本来限定
する必要はないが、靱性、延性や経済性等を総合的に判
断してＮｉ含有量を２．０％以下とした。Therefore, the second invention is characterized in that the descaling of the above invention is carried out on a steel material having a Si content of 0.2 to 2.0%, and the third invention is the descaling of the above invention. It is characterized in that it is carried out for a steel material having a Ni content of 0.2 to 2.0%. Si content is 0.2
When the content is more than%, fire light is generated in the scale during heating and the secondary scale, so that the fire light penetrates deeply into the interface of the base metal, and scale peeling becomes extremely difficult.
According to the method of the present invention, it is possible to perform more effective descaling on a steel sheet containing 0.2% or more of Si, which is difficult to scale off. Although there is no need to limit the upper limit, since the weldability and cold workability deteriorate, the Si content is limited to 2.0% or less. On the other hand, when Ni exceeds 0.2%, the unevenness of the interface of the base metal becomes remarkable, and scale peeling becomes difficult. According to the method of the present invention, for such a steel plate,
Descaling becomes possible more effectively. The upper limit is not necessarily limited, but the Ni content is set to 2.0% or less by comprehensively judging toughness, ductility, economy and the like.
【００１４】第１の発明のデスケーリングはまた、鋼材
温度が８５０〜１０００℃の鋼材に対して実施するのが
望ましい。デスケーリングを８５０℃以下で実施する
と、スケールの強度が地鉄強度より上昇してしまい、ス
ケール剥離が困難となる。また、過度に鋼板温度が低下
すると、圧延性、通板性が悪化し、圧延不可となる場合
もある。８５０℃以上では冷却ひずみ効果が生じ易くな
ってスケール剥離効果が増大し、効率よくデスケーリン
グ可能である。一方、１０００℃以上では生成スケール
の状況が異なることを知見した。本発明者らは数多くの
生成スケールの状況を観察した結果、スケール中の空孔
がスケール剥離性の良否に大きく影響することを見出し
た。すなわち１０００℃以上になると、酸化の進行が著
しく早くなるため、スケール厚が増加するとともに、ス
ケール中に大きな空孔が生成し、この空孔による緩衝で
スケール剥離が困難となり、スケールが残存し易くな
る。The descaling according to the first aspect of the present invention is also preferably performed on a steel material having a steel material temperature of 850 to 1000 ° C. When the descaling is performed at 850 ° C. or less, the scale strength becomes higher than the base steel strength, and scale peeling becomes difficult. Further, if the steel sheet temperature is excessively lowered, the rolling property and the threading property may be deteriorated and the rolling may become impossible. When the temperature is 850 ° C. or higher, the cooling strain effect easily occurs, the scale peeling effect increases, and efficient descaling is possible. On the other hand, it was found that the situation of production scale was different at 1000 ° C or higher. As a result of observing a lot of generated scales, the present inventors have found that the pores in the scale have a great influence on the quality of scale releasability. That is, when the temperature is 1000 ° C. or higher, the progress of oxidation is significantly accelerated, the scale thickness increases, and large pores are generated in the scale, which makes it difficult to exfoliate the scale and the scale easily remains. Become.
【００１５】したがって第４の好ましい発明は、上記発
明のデスケーリングを鋼材温度が８５０〜１０００℃の
鋼材に対して行うことを特徴とする。本発明者らはま
た、デスケーリングによるスケール剥離性を向上させる
には、地鉄とスケール界面をフラットにさせると共に、
鋼材表面にクラックを生じさせることが必要であると考
え、この要因と考える圧下率とスケール剥離性との関連
について調査した。すなわち、仕上圧延前の粗圧延にお
ける各パスの圧下率及び仕上圧延前までの累積圧下率に
ついて、上記各パスの圧下率及び累積圧下率を変えたと
きのスケール残存率を調査した。その結果、仕上圧延前
までの各パスの圧下率及び仕上圧延前までの累積圧下率
は、とくに前者の各パスの圧下率が２５％以上で、かつ
後者の累積圧下率が８５％以上の鋼材に対し上記デスケ
ーリングを実施すると、スケール残存率の著しい低下が
見られた。このことは、上記圧下率による圧延により、
鋼材表面にクラックが入り易くなり、スケールが容易に
剥離し易くなったためと思われる。Therefore, a fourth preferred invention is characterized in that the descaling of the above invention is performed on a steel material having a steel material temperature of 850 to 1000 ° C. In order to improve the scale peeling property by descaling, the present inventors also make the base metal and the scale interface flat, and
We considered that it is necessary to generate cracks on the steel surface, and investigated the relationship between this factor, which is considered to be the reduction ratio, and scale releasability. That is, with respect to the rolling reduction of each pass in rough rolling before finish rolling and the cumulative rolling reduction up to finish rolling, the scale remaining rate when the rolling reduction of each pass and the cumulative rolling reduction was changed was investigated. As a result, the reduction ratio of each pass before finish rolling and the cumulative reduction ratio before finish rolling are steel products in which the reduction ratio of each pass of the former is 25% or more and the cumulative reduction ratio of the latter is 85% or more. On the other hand, when the above-mentioned descaling was carried out, the scale residual rate was remarkably reduced. This means that by rolling with the above reduction ratio,
It is considered that the steel surface was easily cracked and the scale was easily peeled off.
【００１６】したがって第５の好ましい発明は、上記発
明のデスケーリングを仕上圧延前の粗圧延における各パ
スの圧下率を２５％以上とし、かつ圧延開始点から仕上
圧延前までの累積圧下率が８５％以上の鋼材に対して行
うことを特徴とする。Therefore, in a fifth preferred aspect of the present invention, the descaling of the above invention is performed so that the rolling reduction of each pass in rough rolling before finish rolling is 25% or more, and the cumulative rolling reduction from the rolling start point to before finish rolling is 85. % Or more of the steel material.
【発明の実施の形態】図１に示す仕上圧延機２の入側に
は、スラブの移動方向と直交する方向に配置した１列又
は複数列のノズルヘッダー（ノズル高さ２５０〜３００
mm）よりなるＦＳＢ３が配置され、スラブ全長が最終粗
圧延を終えて粗圧延機１から送り出されたのち、仕上圧
延機２入側のＦＳＢ３を通過するまでの経過時間が３０
〜３００秒となり、かつ粗圧延における各パスの圧下率
を２５％以上で、圧延開始点から仕上圧延前までの累積
圧下率が８５％以上となるように鋼材４を通板させた状
態で、ＦＳＢ３より吐出圧力２５０〜６００kgf/cm2 の
高圧水ジェットを噴射し、デスケーリングする。BEST MODE FOR CARRYING OUT THE INVENTION On the inlet side of a finish rolling mill 2 shown in FIG.
mm) is arranged, and the elapsed time from when the slab full length has finished the final rough rolling and after being sent from the rough rolling mill 1 to passing through the FSB 3 on the entry side of the finish rolling mill 2 is 30
~ 300 seconds, and the rolling reduction of each pass in the rough rolling is 25% or more, and in the state where the steel material 4 is threaded so that the cumulative reduction from the rolling start point to before the finish rolling is 85% or more, A high-pressure water jet with a discharge pressure of 250 to 600 kgf / cm 2 is jetted from the FSB 3 to descale.
【００１７】[0017]
【実施例】表１に示す鋼材Ａ、Ｂ及びＣについて、図１
の仕上圧延機２入側に設けたＦＳＢ３より表２に示した
操業条件で粗圧延機１より送り出された鋼材４に対しデ
スケーリングしたのち、仕上圧延を行い、得られた鋼材
表面のスケール残存率を定量的に評価した。その結果を
表２に併記した。EXAMPLE FIG. 1 shows the steel materials A, B and C shown in Table 1.
After the descaling of the steel material 4 sent from the rough rolling machine 1 under the operating conditions shown in Table 2 by the FSB 3 provided on the entry side of the finishing rolling machine 2, finish rolling is performed, and the scale remains on the surface of the obtained steel material. The rate was evaluated quantitatively. The results are shown in Table 2.
【００１８】表２に示されるように、本発明の範囲内に
あるＮｏ．３〜５、７、９〜１３の鋼材は、それぞれス
ケール残存率が１％以下となり、更に吐出圧力、圧下
率、粗圧延終了後、デスケーリングまでの経過時間、デ
スケーリング温度を調整したＮｏ．３、４、７、９、１
２の鋼材では、スケール残存は皆無であった。しかしな
がら、吐出圧力で本発明の範囲を外れたＮｏ．１の鋼材
及びスラブ全長が粗圧延を終えてからＦＳＢに達するま
での経過時間が本発明の範囲を外れたＮｏ．２、６、８
の鋼材は、スケール残存率がＮｏ．１で５２％、Ｎｏ．
２で３５％、Ｎｏ．６で７２％、Ｎｏ．８で１２％に達
した。なお、Ｎｏ．８の鋼材においてはデスケーリング
までの経過時間が長く、鋼材の温度低下により仕上圧延
時に絞り込みが発生し、成品に成り得なかった。As shown in Table 2, No. 1 within the scope of the present invention. The steel materials of Nos. 3 to 5, 7, and 9 to 13 each had a scale residual rate of 1% or less. Further, the discharge pressure, the rolling reduction, the elapsed time until the descaling after the completion of rough rolling, and the descaling temperature were adjusted. 3, 4, 7, 9, 1
With the steel material No. 2, no scale remained. However, the discharge pressure was outside the range of the present invention. The elapsed time from the completion of rough rolling of the steel material and slab full length of 1 to reaching FSB falls outside the range of the present invention. 2, 6, 8
No. 2 has a residual scale rate of No. 52% in No. 1, No. 1
35% for No. 2, No. 72% in No. 6, No. 6 At 8 it reached 12%. In addition, No. In the steel material of No. 8, the elapsed time until descaling was long, and narrowing occurred during finish rolling due to the temperature decrease of the steel material, and it could not be a finished product.
【００１９】[0019]
【表１】 [Table 1]
【００２０】[0020]
【表２】 [Table 2]
【００２１】[0021]
【発明の効果】本発明によれば、従来スケール除去が困
難と考えられていた高Ｓｉ含有鋼及びＮｉ含有鋼に対し
ても、スラブ全長が最終粗圧延を終えて粗圧延機から送
り出されたのち、ＦＳＢを通過するまの経過時間を３０
〜３００秒に設定し、かつＦＳＢからの吐出圧力を２５
０〜６００kgf/cm2 にしてデスケーリングすることによ
り、スケール除去が行われ、スケール疵のない表面性状
の良好な熱延鋼板を得ることができる。According to the present invention, even for high Si-containing steel and Ni-containing steel, which were conventionally considered to be difficult to remove scale, the full length of the slab was sent from the rough rolling machine after the final rough rolling. After that, the elapsed time before passing through the FSB is 30
~ 300 seconds and set the discharge pressure from FSB to 25
By performing descaling at 0 to 600 kgf / cm 2 , scale removal is performed, and a hot-rolled steel sheet with good surface properties without scale flaws can be obtained.
【００２２】また、デスケーリングを鋼材温度８５０〜
１０００℃の鋼材に対して行うことにより、及び若しく
はデスケーリングを実施する鋼材の圧下率を、仕上圧延
前の粗圧延における各パスの圧下率を２５％以上、圧延
開始点から仕上圧延前までの累積圧下率を８５％以上と
することにより、デスケーリングによるスケールの剥離
性をより一層向上させることができる。Further, descaling is carried out at a steel material temperature of 850 to 850.
The reduction rate of the steel material to be subjected to descaling by performing it on the steel material at 1000 ° C. is 25% or more for the reduction rate of each pass in rough rolling before finish rolling, and from the rolling start point to before finish rolling. By setting the cumulative rolling reduction to 85% or more, the scale releasability due to descaling can be further improved.
【図１】圧延ラインの模式図。FIG. 1 is a schematic diagram of a rolling line.
【図２】デスケーリング吐出圧力とスケール残存率の関
係を示す図。FIG. 2 is a diagram showing a relationship between a descaling discharge pressure and a scale residual rate.
１・・粗圧延機 ２・・仕上圧延機 ３・・ＦＳＢ ４・・鋼材 1 ・ ・ Rough rolling mill 2 ・ ・ Finishing rolling mill 3 ・ ・ FSB 4 ・ ・ Steel material
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｃ２２Ｃ 38/08 Ｃ２２Ｃ 38/08 (72)発明者 栗田 俊哉 広島県呉市昭和町11番１号 日新製鋼株式 会社呉製鉄所内 (72)発明者 平松 昭史 広島県呉市昭和町11番１号 日新製鋼株式 会社技術研究所内 (72)発明者 面迫 浩次 広島県呉市昭和町11番１号 日新製鋼株式 会社技術研究所内 (72)発明者 山田 利郎 広島県呉市昭和町11番１号 日新製鋼株式 会社技術研究所内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Reference number within the agency FI Technical display location C22C 38/08 C22C 38/08 (72) Inventor Toshiya Kurita 11-1 Showa-cho, Kure City, Hiroshima Prefecture Nisshin Steel Co., Ltd.Kure Works (72) Inventor Akifumi Hiramatsu 11-11 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Technical Research Institute (72) Inventor Koji Osasako 11-11, Kure-shi, Hiroshima No. 11 Research Institute of Nisshin Steel Co., Ltd. (72) Inventor Toshiro Yamada 11-1 Showa-cho, Kure City, Hiroshima Prefecture Research Institute of Nisshin Steel Co., Ltd.
Claims (5)
のに際し、スラブの全長が最終粗圧延を終えて粗圧延機
から送り出されたのち、仕上圧延前のスケールブレーカ
ーを通過するまでの経過時間が３０〜３００秒となるよ
うにスラブを通板させ、吐出圧力２５０〜６００kgf/cm
2 の高圧水ジェットによるデスケーリングを仕上圧延前
で実施することを特徴とする熱延鋼板の製造方法。1. When manufacturing a hot-rolled steel sheet by hot rolling a slab, the entire length of the slab is sent from a rough rolling machine after final rough rolling, and then passes through a scale breaker before finish rolling. The slab is passed through so that the elapsed time of 30 to 300 seconds, and the discharge pressure is 250 to 600 kgf / cm.
A method for manufacturing a hot-rolled steel sheet, characterized in that descaling by the high-pressure water jet in 2 is performed before finish rolling.
象とする請求項１記載の熱延鋼板の製造方法。2. The method for producing a hot-rolled steel sheet according to claim 1, wherein the steel material has a Si content of 0.2 to 2.0%.
象とする請求項１又は２記載の熱延鋼板の製造方法。3. The method for producing a hot-rolled steel sheet according to claim 1, wherein the steel material has a Ni content of 0.2 to 2.0%.
０℃の鋼材に対して行われる請求項１ないし３のいづれ
かの請求項に記載の熱延鋼板の製造方法。4. A steel material temperature of 850 to 100 for descaling.
The method for producing a hot-rolled steel sheet according to any one of claims 1 to 3, which is performed on a steel material at 0 ° C.
での各パスの圧下率を２５％以上とし、かつ圧延開始点
からの累積圧下率が８５％以上の鋼材に対して行うこと
を特徴とする請求項１ないし４のいづれかの請求項に記
載の熱延鋼板の製造方法。5. Descaling is performed on a steel material having a rolling reduction of 25% or more in each pass from rough rolling to finish rolling and a cumulative rolling reduction of 85% or more from a rolling start point. The method for manufacturing a hot-rolled steel sheet according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25981295A JPH09103817A (en) | 1995-10-06 | 1995-10-06 | Manufacture of hot rolled steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25981295A JPH09103817A (en) | 1995-10-06 | 1995-10-06 | Manufacture of hot rolled steel sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09103817A true JPH09103817A (en) | 1997-04-22 |
Family
ID=17339349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25981295A Withdrawn JPH09103817A (en) | 1995-10-06 | 1995-10-06 | Manufacture of hot rolled steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09103817A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2130938A4 (en) * | 2007-03-27 | 2017-06-21 | Nippon Steel & Sumitomo Metal Corporation | High-strength hot rolled steel sheet being free from peeling and excelling in surface and burring properties and process for manufacturing the same |
-
1995
- 1995-10-06 JP JP25981295A patent/JPH09103817A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2130938A4 (en) * | 2007-03-27 | 2017-06-21 | Nippon Steel & Sumitomo Metal Corporation | High-strength hot rolled steel sheet being free from peeling and excelling in surface and burring properties and process for manufacturing the same |
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