JP3333405B2 - Descaling method of hot rolled steel strip by high pressure rolling - Google Patents
Descaling method of hot rolled steel strip by high pressure rollingInfo
- Publication number
- JP3333405B2 JP3333405B2 JP26923096A JP26923096A JP3333405B2 JP 3333405 B2 JP3333405 B2 JP 3333405B2 JP 26923096 A JP26923096 A JP 26923096A JP 26923096 A JP26923096 A JP 26923096A JP 3333405 B2 JP3333405 B2 JP 3333405B2
- Authority
- JP
- Japan
- Prior art keywords
- steel strip
- scale
- rolling
- hot
- rolled steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 73
- 239000010959 steel Substances 0.000 title claims description 73
- 238000005096 rolling process Methods 0.000 title claims description 53
- 238000000034 method Methods 0.000 title claims description 13
- 238000005554 pickling Methods 0.000 claims description 36
- 230000009467 reduction Effects 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 7
- 239000010410 layer Substances 0.000 description 20
- 238000005097 cold rolling Methods 0.000 description 12
- 239000007921 spray Substances 0.000 description 8
- 241000316887 Saissetia oleae Species 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 4
- 239000012634 fragment Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 230000001680 brushing effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 238000004299 exfoliation Methods 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 239000006061 abrasive grain Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Metal Rolling (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
- Control Of Metal Rolling (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高圧下圧延で熱延スケ
ールを鋼帯表面から除去し、酸洗負荷を軽減したディス
ケーリング方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a descaling method in which hot-rolled scale is removed from the surface of a steel strip by high-pressure rolling to reduce the pickling load.
【０００２】[0002]
【従来の技術】熱間圧延された鋼帯は、酸化物を主体と
するスケールで表面が覆われている。この熱延鋼帯を、
そのまま冷延等の下工程に送ると、熱延スケールに起因
する表面疵やクラック等の欠陥が発生する原因となる。
そこで、通常、酸洗によって熱延スケールを除去し、熱
延鋼帯を下工程に搬送している。この方法では、酸洗設
備，廃酸処理，脱スケール能の調整等の点で問題があ
り、また酸洗時に発生する水素の侵入によって鋼材の特
性が劣化する虞れもある。酸洗に起因する諸問題を解決
するため、酸洗工程に送り込まれる熱延鋼帯のスケール
を除去する方法が種々検討されている。たとえば、スケ
ールが付着した熱延鋼帯を高圧下率で冷間圧延すること
（以下、黒皮圧延という）が特公昭５４−１３３４６０
号公報，特開昭５７−４１８２１号公報，特開昭５７−
１０９１７号公報等で紹介されている。高圧下率の冷間
圧延により、スケールに亀裂が発生し、また鋼帯に対す
る付着力が低下するので、ショットブラスト，高圧水噴
射，ブラッシング，砥粒研削等により冷間圧延後の鋼帯
から容易に分離される。その結果、酸洗槽に搬入される
熱延鋼帯に付着しているスケールが少なくなり、酸洗工
程の負荷が軽減する。2. Description of the Related Art A hot-rolled steel strip is covered with a scale mainly composed of an oxide. This hot rolled steel strip
If it is sent to a lower step such as cold rolling as it is, it causes defects such as surface flaws and cracks due to the hot rolling scale.
Therefore, the hot-rolled steel strip is usually removed by pickling, and the hot-rolled steel strip is transported to a lower step. This method has problems in pickling equipment, waste acid treatment, adjustment of descaling ability, and the like, and there is also a possibility that the properties of the steel material may be deteriorated due to intrusion of hydrogen generated during pickling. In order to solve various problems caused by the pickling, various methods for removing the scale of the hot-rolled steel strip sent to the pickling step have been studied. For example, cold rolling of a hot-rolled steel strip to which scale is attached at a high pressure ratio (hereinafter referred to as black scale rolling) is disclosed in Japanese Patent Publication No. 54-133460.
JP, JP-A-57-41821, JP-A-57-41821,
No. 10917, and the like. Cold rolling at a high pressure ratio causes cracks in the scale and decreases the adhesive force to the steel strip, so it can be easily removed from the steel strip after cold rolling by shot blasting, high pressure water injection, brushing, abrasive grinding, etc. Is separated into As a result, the scale attached to the hot-rolled steel strip carried into the pickling tank is reduced, and the load of the pickling step is reduced.
【０００３】[0003]
【発明が解決しようとする課題】熱延鋼帯を高圧下率で
黒皮圧延するとき、確かに酸洗工程の負荷が軽減される
ものの、鋼帯表面から剥離したスケールの破片が圧延ロ
ールによって鋼帯表面に押し付けられる。スケールに比
較して鋼帯が軟質であるため、ロールによる押圧力でス
ケールの破片が鋼帯表面に圧着され、或いは押し込まれ
る虞れがある。鋼帯表面に押し込まれた破片は、酸洗工
程での除去が困難になり、後続する冷間圧延工程で表面
疵等の欠陥を発生させる原因となる。そのため、たとえ
ば砥粒研削等によってスケール破片を除去しているが、
依然として鋼帯表面に残留するものがある。このような
ことから、黒皮圧延は、高品質の表面肌が要求される冷
延鋼帯の製造には適していないものとされていた。そし
て、前述した種々の問題があるものの、酸洗によるディ
スケーリングが主流になっている現状である。When the hot-rolled steel strip is subjected to black scale rolling at a high pressure reduction rate, the load of the pickling process is certainly reduced, but the scale fragments separated from the steel strip surface are removed by the rolling roll. Pressed against steel strip surface. Since the steel strip is softer than the scale, fragments of the scale may be pressed or pushed into the steel strip surface by the pressing force of the roll. Fragments pushed into the surface of the steel strip are difficult to remove in the pickling process and cause defects such as surface flaws in the subsequent cold rolling process. Therefore, scale fragments are removed by, for example, abrasive grinding.
Some still remain on the steel strip surface. For these reasons, it has been considered that black scale rolling is not suitable for producing a cold-rolled steel strip requiring a high quality surface skin. In spite of the various problems described above, descaling by pickling is currently the mainstream.
【０００４】本発明者等は、酸洗負荷の軽減に有効であ
る黒皮圧延の長所を活かすことを狙って、製品に表面疵
を発生させる残留スケールに対する対策を種々検討し
た。その結果、黒皮圧延後の鋼帯表面をブラッシング及
びスプレー処理するとき残留スケールのほぼ全量が除去
されること、また圧延機のワークロールに熱延鋼帯から
転写されたスケール片をポリッシャー，高圧水スプレ
ー，スクレーパ等で取り除くとき、鋼帯表面に残留する
スケール自体も大幅に少なくなることを見い出し、別途
出願した。このようにして、酸洗前の圧延で効率よくデ
ィスケーリングし、酸洗槽に持ち込まれるスケールを減
少させるとき、酸洗負荷が軽減される。本発明は、先願
で提案した黒皮圧延によるディスケーリングを更に改良
したものであり、高圧下圧延に使用するロール径を板厚
との関係で特定することにより、基地鋼からのスケール
の剥離を促進させ、軽度の酸洗によっても残存スケール
が内表面状態の鋼帯を得ることを目的とする。[0004] The present inventors have studied various measures against residual scale that causes surface flaws in products, with the aim of taking advantage of black scale rolling, which is effective in reducing the pickling load. As a result, almost all of the residual scale is removed when brushing and spraying the surface of the steel strip after the black scale rolling, and the scale pieces transferred from the hot-rolled steel strip to the work roll of the rolling mill are polished with a high pressure. When removing with a water spray, a scraper, etc., it was found that the scale itself remaining on the steel strip surface was significantly reduced, and a separate application was filed. In this way, when the scale before rolling is pickled efficiently by rolling before pickling and the scale brought into the pickling tank is reduced, the pickling load is reduced. The present invention is a further improvement of the descaling by black scale rolling proposed in the prior application, and by separating the roll diameter used for high-pressure rolling in relation to the sheet thickness, the peeling of the scale from the base steel is performed. It is an object of the present invention to obtain a steel strip having a residual scale in an inner surface state even by mild pickling.
【０００５】[0005]
【課題を解決するための手段】本発明は、その目的を達
成するため、表面に熱延スケールが付着している熱延鋼
帯を酸洗に先立って高圧下率で冷間圧延する際、ワーク
ロールの半径をＲ（ｍｍ），圧延後の板厚をｈ（ｍｍ）
とするとき、２Ｒ≧１８０×ｈの大径ロールを使用し、
３０％以上の圧下率で熱延鋼帯を冷間圧延することによ
り、熱延鋼帯の基地鋼から熱延スケールを除去し、次い
で熱延鋼帯を酸洗工程に搬送する 熱延スケールの粉砕物は、圧延ロールの表面に対向配置
したポリッシャー，スプレーノズル，スクレーパ等によ
ってロール表面から除去され、系外に排出することが好
ましい。ポリッシャー，スプレーノズル，スクレーパ等
は、回転方向に関して圧下点よりも下流側の位置でワー
クロールの周面に対向配置される。また、ワークロール
に接して回転するバックアップロールに対しても、同様
なポリッシャー，スプレーノズル，スクレーパ等を設け
てもよい。SUMMARY OF THE INVENTION In order to achieve the object, the present invention provides a method for cold rolling a hot-rolled steel strip having a hot-rolled scale adhered to a surface thereof under a high-pressure reduction prior to pickling. The radius of the work roll is R (mm) and the thickness after rolling is h (mm)
When using a large diameter roll of 2R ≧ 180 × h,
The hot-rolled steel strip is cold-rolled at a rolling reduction of 30% or more to remove the hot-rolled scale from the base steel of the hot-rolled steel strip, and then transport the hot-rolled steel strip to the pickling process. It is preferable that the pulverized material is removed from the roll surface by a polisher, a spray nozzle, a scraper, or the like disposed opposite to the surface of the rolling roll, and discharged to the outside of the system. The polisher, the spray nozzle, the scraper, and the like are arranged facing the peripheral surface of the work roll at a position downstream of the rolling point in the rotation direction. Further, a similar polisher, spray nozzle, scraper and the like may be provided for a backup roll which rotates in contact with a work roll.
【０００６】本発明に従ったラインは、図１に示すよう
に構築される。熱延スケールが付着したままの熱延鋼帯
１は、ペイオフリール２から巻き戻され、ブライドルロ
ール３を経て冷間圧延機４で高圧下圧延される。熱延ス
ケールは、高圧下圧延によって亀裂，粉砕され、鋼帯１
から剥離される。鋼帯表面に残留しているスケール粉砕
物をブラシ５で除去した後、更にスプレー装置６に導入
され、スプレーノズル７から高圧水を吹き付けることに
よって鋼帯の表面が清浄化される。このように処理され
た鋼帯は、次いで酸洗槽８に送り込まれ、表面に僅かに
残っているスケールが酸洗除去される。そして、巻取り
リール９で巻き取られる。冷間圧延機４は、圧下率が３
０％以上となるように調整される。このような高圧下率
が熱延鋼帯１のディスケーリングに有効である理由を、
本発明者等は次のように考察した。A line according to the present invention is constructed as shown in FIG. The hot-rolled steel strip 1 with the hot-rolled scale adhered is unwound from the payoff reel 2, passed through bridle rolls 3, and rolled under high pressure by a cold rolling mill 4. The hot rolled scale is cracked and pulverized by high pressure rolling,
Peeled off from After the scale pulverized matter remaining on the steel strip surface is removed by the brush 5, the scale pulverized product is further introduced into the spray device 6, and the surface of the steel strip is cleaned by spraying high-pressure water from the spray nozzle 7. The steel strip treated in this way is then sent to a pickling tank 8, where scales slightly remaining on the surface are pickled and removed. Then, it is taken up by the take-up reel 9. The cold rolling mill 4 has a draft of 3
It is adjusted to be 0% or more. The reason why such high pressure reduction is effective for descaling of the hot-rolled steel strip 1 is as follows.
The present inventors have considered as follows.
【０００７】熱延鋼帯１の表面に形成されているスケー
ルは、主としてＦｅ3 Ｏ4 で構成されるが、概念的には
内部から表層に向かって酸素濃度が順次高くなるＦｅＯ
層，Ｆｅ3 Ｏ4 層及びＦｅ2 Ｏ3 層が基地鋼の表面に積
層された構造をもつものと考えられる。実際、急冷され
た鋼帯ほどＦｅＯ層が厚くなる傾向を示す。スケール層
は、弱脱酸鋼では６〜７μｍと比較的薄く、Ｔｉキルド
鋼では９〜１０μｍと比較的厚くなっている。The scale formed on the surface of the hot-rolled steel strip 1 is mainly composed of Fe 3 O 4. Conceptually, FeO in which the oxygen concentration gradually increases from the inside toward the surface layer.
It is considered that the layer, the Fe 3 O 4 layer and the Fe 2 O 3 layer have a structure laminated on the surface of the base steel. In fact, the more rapidly the steel strip is cooled, the thicker the FeO layer tends to be. The scale layer is relatively thin at 6 to 7 μm for weakly deoxidized steel, and relatively thick at 9 to 10 μm for Ti-killed steel.
【０００８】スケール層の大半を占めるＦｅ3 Ｏ4 層及
びＦｅ2 Ｏ3 層は硬質で脆く、比較的低い圧下力でもク
ラックが入り易い。たとえば、酸洗の前工程として組み
込まれている従来のテンションレベラー程度の圧下力
（約２％）や機械的な繰返し曲げ加工でも、クラックが
入り剥離する。硫酸酸洗でみられるような機械的な繰返
し曲げを与える装置でも、Ｆｅ2 Ｏ3 層，Ｆｅ3 Ｏ4 層
に亀裂を付けることができる。これに対し、基地鋼との
界面にあるＦｅＯ層は、展延性があり、低い圧下率では
基地鋼の伸びに従って変形する。そのため、テンション
レベラー程度の圧下力で下地鋼から剥離せず、酸洗槽に
持ち込まれる。しかし、３０％以上の高い圧延率に設定
すると、基地鋼とＦｅＯ層との変形量の差が大きくな
り、基地鋼の伸びに追従できなくなったＦｅＯ層にクラ
ックが発生する。クラックの発生は、圧延率が高いほど
顕著となる。しかし、高過ぎる圧延率では、圧延荷重が
高くなり、ロールバイト部での面圧が大きくなり、基地
鋼にスケールを押し込み圧着する場合がある。そのた
め、高過ぎる圧延率では却って脱スケール性が劣化する
傾向がみられる。The Fe 3 O 4 layer and the Fe 2 O 3 layer, which occupy most of the scale layer, are hard and brittle, and easily crack even with a relatively low rolling force. For example, cracking occurs and peels off even with a rolling force (approximately 2%) of a conventional tension leveler or a mechanical repeated bending process incorporated as a pre-process of pickling. Cracks can be formed in the Fe 2 O 3 layer and the Fe 3 O 4 layer even with a device that gives mechanical repetitive bending as seen in sulfuric acid pickling. On the other hand, the FeO layer at the interface with the base steel has ductility, and deforms at a low rolling reduction according to the elongation of the base steel. For this reason, the steel sheet is not peeled off from the base steel by the rolling force of the tension leveler and is taken into the pickling tank. However, when a high rolling reduction of 30% or more is set, the difference in the deformation between the base steel and the FeO layer becomes large, and cracks occur in the FeO layer that cannot follow the elongation of the base steel. The occurrence of cracks becomes more remarkable as the rolling ratio increases. However, if the rolling ratio is too high, the rolling load increases, the surface pressure at the roll bite increases, and the scale may be pushed into the base steel and pressed. Therefore, if the rolling ratio is too high, the tendency of descaling tends to be rather deteriorated.
【０００９】実際、冷間圧延で熱延鋼帯表面から剥離し
たスケールの粉砕物を調査してみると、圧下率が低いと
きには剥離したスケールが粉粒状であるのに対し、圧下
率の上昇に伴って粉砕物のサイズが大きく鱗片状になっ
てくることが観察される。この圧下率に応じた剥離スケ
ールの状態変化は、高圧下率の圧延になるほどスケール
層の深くまで，換言すればＦｅＯ層まで入ったクラック
を起点としてスケール剥離が生じ、スケール剥離量が多
くなる原因であると推察される。その結果、圧延後の鋼
帯表面に残存するスケールが大幅に少なくなる。基地鋼
とスケールとの延性の差を利用してディスケーリングす
るとき、ロール圧下による不均一変形を大きくすること
が有効である。すなわち、圧延時のメタルフローは、図
３（ａ）に示すように不均一変形である。また、鋼板の
表面近傍と厚み方向中心部には、図３（ｂ）に示すよう
に変形程度の差がある。この圧延形態及びスケール層と
基地鋼の延性差により、スケール層に剥離が生じる。こ
の不均一変形では、ワークロールと鋼板表面（スケール
面）間に働く摩擦係数μが大きいとき、表面に働く剪断
力τ（＝μＰ）も大きく、結果としてスケールが剥離す
る。In fact, when the pulverized material of the scale peeled from the surface of the hot-rolled steel strip by the cold rolling is examined, when the rolling reduction is low, the peeled scale is in the form of powder and granules. It is observed that the size of the pulverized material becomes large and scale-like. This change in the state of the exfoliated scale according to the rolling reduction is caused by the fact that as the rolling becomes higher in the high rolling reduction, the scale exfoliation starts from a crack that has entered the scale layer, in other words, a crack that has entered the FeO layer, and the scale exfoliation amount increases. It is inferred that As a result, the scale remaining on the surface of the steel strip after rolling is significantly reduced. When performing descaling using the difference in ductility between the base steel and the scale, it is effective to increase the non-uniform deformation due to roll reduction. That is, the metal flow during rolling is non-uniform deformation as shown in FIG. Further, there is a difference in the degree of deformation between the vicinity of the surface of the steel sheet and the center in the thickness direction, as shown in FIG. Due to this rolling mode and the difference in ductility between the scale layer and the base steel, the scale layer is peeled. In this non-uniform deformation, when the friction coefficient μ acting between the work roll and the steel plate surface (scale surface) is large, the shear force τ (= μP) acting on the surface is also large, and as a result, the scale peels.
【００１０】そこで、本発明者等は、板厚方向の不均一
変形に及ぼすワークロールの影響を種々調査検討した。
その結果、後述する実施例でも明らかなように、２Ｒ≧
１８０×ｈ［ただし、Ｒ：ワークロールの半径（ｍ
ｍ），ｈ：圧延後の板厚（ｍｍ）］の大径ロールを使用
することによって、スケール剥離が促進されることを見
い出した。大径ロールは、圧延荷重を大きくし、結果と
して鋼帯表面に作用する剪断力τを大きくする。また、
ロール径が大きいことから、鋼帯に接触するワークロー
ルの接触弧長が長くなることによっても不均一変形が大
きくなる。なかでも、２Ｒ≧１８０×ｈの大径ロール
は、スケール剥離に顕著な効果を発揮する。ＦｅＯ層と
下地鋼との界面からスケールが剥離されると、圧延後の
鋼帯表面に残存するスケールが大幅に少なくなる。ま
た、圧延ロールに付着しているスケール片をポリッシン
グ，ブラッシング，スプレー処理等で除去しながら高圧
下圧延するとき、圧延ロール表面に移し取られたスケー
ル片に起因する問題が解消され、従来の黒皮圧延材では
みられない優れた表面性状をもつ鋼帯が得られる。その
ため、酸洗工程の負荷が大幅に軽減され、酸洗槽の小規
模化，酸洗時間の短縮，低濃度酸液の使用等が可能にな
る。また、冷間圧延時の圧下率を調整することによっ
て、酸洗後の製品板厚をもつ冷延鋼板を得ることもでき
る。Therefore, the present inventors conducted various investigations and examined the effect of the work roll on the non-uniform deformation in the thickness direction.
As a result, as is clear from the examples described later, 2R ≧
180 × h [where R: radius of work roll (m
m), h: plate thickness after rolling (mm)], it was found that scale peeling was promoted by using a large-diameter roll. The large-diameter roll increases the rolling load and consequently increases the shear force τ acting on the steel strip surface. Also,
Since the roll diameter is large, the nonuniform deformation increases even when the contact arc length of the work roll that contacts the steel strip increases. Among them, a large-diameter roll of 2R ≧ 180 × h exerts a remarkable effect on scale peeling. When the scale is peeled off from the interface between the FeO layer and the base steel, the scale remaining on the steel strip surface after rolling is significantly reduced. In addition, when rolling under high pressure while removing scale pieces adhering to the rolling rolls by polishing, brushing, spraying, etc., the problem caused by the scale pieces transferred to the surface of the rolling rolls is solved, and the conventional black color is eliminated. A steel strip having excellent surface properties not found in rolled steel can be obtained. Therefore, the load of the pickling step is greatly reduced, and the pickling tank can be downsized, the pickling time can be reduced, and a low-concentration acid solution can be used. Further, by adjusting the rolling reduction at the time of cold rolling, a cold rolled steel sheet having a product thickness after pickling can be obtained.
【００１１】[0011]
【実施例】板厚２．７ｍｍの熱延鋼帯を、酸洗に先立っ
て圧下率４５％で冷間圧延した。熱延鋼帯には、表１に
示す成分・組成を持ち、表面に平均厚み１０〜１５μｍ
の熱延スケールが付着したままの熱延鋼帯を使用した。
このとき、ワークロールの胴長と同じ長さを持ち、シリ
カ又はアルミナ砥粒入りナイロンブラシ製のロール状ポ
リッシャーを、ワークロールの周面に加圧力１〜４Ｎ／
ｍｍ2 で押し付け、ポリッシャーを従動回転させた。ま
た、ワークロールに臨んでいる部分を除き、ポリッシャ
ーを吸引機のフードに収め、ポリッシャー周辺の空気を
流量１〜２０Ｎｍ3 ／分で吸引した。EXAMPLE A hot-rolled steel strip having a thickness of 2.7 mm was cold-rolled at a rolling reduction of 45% prior to pickling. The hot-rolled steel strip has the components and compositions shown in Table 1, and has an average thickness of 10 to 15 μm on the surface.
The hot-rolled steel strip with the hot-rolled scale of No. 1 attached was used.
At this time, a roll-shaped polisher having the same length as the body length of the work roll and made of a nylon brush containing silica or alumina abrasive grains is applied to the peripheral surface of the work roll with a pressure of 1 to 4 N /
mm 2 and the polisher was driven to rotate. Except for the part facing the work roll, the polisher was placed in the hood of the suction machine, and the air around the polisher was sucked at a flow rate of 1 to 20 Nm 3 / min.
【００１２】 [0012]
【００１３】圧延後の鋼帯を、図１に示すラインに沿っ
てブラッシング５，スプレー処理６した後、実ラインの
酸液にほぼ等しい１０％ＨＣｌ＋７％Ｆｅ2+＋１％Ｆｅ
3+の割合で調合した酸液（９０℃）を収容した酸洗槽８
に搬送して酸洗した。酸洗後の鋼帯表面に付着している
スケールの個数及びサイズを調査した。スケールの個数
は目視観察でカウントし、単位面積当りの個数（個／ｍ
2）で表した。他方、スケールのサイズはノギス及び光
学顕微鏡で測定した。調査結果を圧延機のロール径で整
理したところ、図４に示す関係が得られた。圧下率３０
％以上の圧延では、十分な脱スケール性を得るための単
位板厚当りの圧下力（Ｐ／ｈ）は２５０ｋｇ／ｍｍ2以
上必要であることが実験データから得られた。図４にお
いて、摩擦係数μ＝０．１で単位板厚当りの圧下力が２
５０ｋｇ／ｍｍ2以上で且つ圧下率３０％以上の場合、
ロール径２Ｒ：板厚ｈの比２Ｒ／ｈは１８０以上を必要
とした。したがって、２Ｒ≧１８０×ｈの関係を満足す
る条件下で圧延することによって、十分な脱スケール性
が得られ、展延性のあるＦｅＯ層を剥離させることも可
能になることが判った。The steel strip after rolling is brushed 5 and sprayed 6 along the line shown in FIG. 1, and then 10% HCl + 7% Fe 2+ + 1% Fe which is almost equal to the acid solution of the actual line.
Pickling tank 8 containing an acid solution (90 ° C.) prepared at a ratio of 3+
And pickled. The number and size of scales adhering to the steel strip surface after pickling were investigated. The number of scales is counted by visual observation, and the number per unit area (pieces / m
2 ). On the other hand, the size of the scale was measured with a caliper and a light microscope. When the investigation results were arranged by the roll diameter of the rolling mill, the relationship shown in FIG. 4 was obtained. Reduction rate 30
From the experimental data, it was found that a rolling force of not less than 250% / mm 2 is required for rolling at a rolling rate of not less than 250% in order to obtain a sufficient descaling property. In FIG. 4, when the friction coefficient μ = 0.1 and the rolling force per unit thickness is 2
In the case of 50 kg / mm 2 or more and a rolling reduction of 30% or more,
The ratio 2R / h of roll diameter 2R: plate thickness h required 180 or more. Therefore, it was found that by performing rolling under a condition satisfying the relationship of 2R ≧ 180 × h, sufficient descaling property was obtained, and it was also possible to peel off a spreadable FeO layer.
【００１４】[0014]
【発明の効果】以上に説明したように、本発明において
は、スケールが付着している熱延鋼帯を高圧下圧延する
ことによりディスケーリングする際、２Ｒ≧１８０×ｈ
のロール径をもつワークロールを使用すると共に、圧下
率を３０％以上に規制している。これにより、熱延鋼帯
表面からスケールが効率よく除去される。このようにし
てディスケーリングされた鋼帯は、後続する工程で軽度
の酸洗によって冷延用素材に調整される。そのため、酸
洗時間の短縮，酸洗設備の小規模化や低濃度酸液の使用
等が可能となり、また酸洗に起因する欠陥が素材に持ち
込まれることも抑制される。As described above, in the present invention, when the hot-rolled steel strip to which the scale is adhered is descaled by rolling under high pressure, 2R ≧ 180 × h
And a reduction rate of 30% or more. Thereby, the scale is efficiently removed from the surface of the hot-rolled steel strip. The steel strip descaled in this way is adjusted to a cold-rolling material by light pickling in a subsequent step. Therefore, it is possible to shorten the pickling time, reduce the size of the pickling equipment, use a low-concentration acid solution, etc., and also suppress the defects caused by the pickling from being introduced into the material.
【図１】 本発明に従った熱延鋼帯のディスケーリング
ラインFIG. 1 shows a descaling line of a hot-rolled steel strip according to the present invention.
【図２】 熱延鋼帯表面に形成されているスケールの層
構成Fig. 2 Layer composition of scale formed on hot rolled steel strip surface
【図３】 熱延鋼帯を高圧下圧延するときのメタルフロ
ー（ａ）及び変形領域（ｂ）FIG. 3 shows a metal flow (a) and a deformed area (b) when a hot-rolled steel strip is rolled under high pressure.
【図４】 ワークロールのロール径がスケール剥離性に
及ぼす影響FIG. 4 Effect of work roll diameter on scale peelability
１：スケールが付着している熱延鋼帯 ２：ペイオフ
リール ３：ブライドルロール ４：冷間圧延機 ５：ブラ
シ ６：スプレー装置 ７：スプレーノズル ８：酸洗槽 ９：巻取りリー
ル1: Hot-rolled steel strip with scale attached 2: Payoff reel 3: Bridle roll 4: Cold rolling mill 5: Brush 6: Spray device 7: Spray nozzle 8: Pickling tank 9: Take-up reel
───────────────────────────────────────────────────── フロントページの続き 審査官 田中 則充 (56)参考文献 特開 昭55−27408（ＪＰ，Ａ) 特開 昭60−145216（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B21B 45/06 B21B 27/02 ────────────────────────────────────────────────── ─── Continued on the front page Examiner Norimitsu Tanaka (56) References JP-A-55-27408 (JP, A) JP-A-60-145216 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B21B 45/06 B21B 27/02
Claims (1)
鋼帯を酸洗に先立って高圧下率で冷間圧延する際、ワー
クロールの半径をＲ（ｍｍ），圧延後の板厚をｈ（ｍ
ｍ）とするとき、２Ｒ≧１８０×ｈの大径ロールを使用
し、３０％以上の圧下率で熱延鋼帯を冷間圧延すること
により、熱延鋼帯の基地鋼から熱延スケールを除去し、
次いで熱延鋼帯を酸洗工程に搬送するディスケーリング
方法。When a hot-rolled steel strip having a hot-rolled scale attached to its surface is cold-rolled at a high pressure ratio before pickling, the radius of the work roll is set to R (mm), and the sheet thickness after rolling. To h (m
m), a large-diameter roll of 2R ≧ 180 × h is used, and the hot-rolled steel strip is cold-rolled at a rolling reduction of 30% or more, so that the hot-rolled scale is removed from the base steel of the hot-rolled steel strip. Remove,
Next, a descaling method of transporting the hot-rolled steel strip to the pickling process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26923096A JP3333405B2 (en) | 1995-11-22 | 1996-09-19 | Descaling method of hot rolled steel strip by high pressure rolling |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32632995 | 1995-11-22 | ||
| JP7-326329 | 1995-11-22 | ||
| JP26923096A JP3333405B2 (en) | 1995-11-22 | 1996-09-19 | Descaling method of hot rolled steel strip by high pressure rolling |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09201615A JPH09201615A (en) | 1997-08-05 |
| JP3333405B2 true JP3333405B2 (en) | 2002-10-15 |
Family
ID=26548678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26923096A Expired - Lifetime JP3333405B2 (en) | 1995-11-22 | 1996-09-19 | Descaling method of hot rolled steel strip by high pressure rolling |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3333405B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009034690A (en) * | 2007-07-31 | 2009-02-19 | Nisshin Steel Co Ltd | Descaling and cold rolling method for hot-rolled steel strip, and work roll for rolling |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108480321A (en) * | 2018-05-30 | 2018-09-04 | 中冶南方工程技术有限公司 | For the stainless steel bright annealing unit band clean device and method of steel plate surface |
-
1996
- 1996-09-19 JP JP26923096A patent/JP3333405B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009034690A (en) * | 2007-07-31 | 2009-02-19 | Nisshin Steel Co Ltd | Descaling and cold rolling method for hot-rolled steel strip, and work roll for rolling |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09201615A (en) | 1997-08-05 |
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