JP4453299B2 - Manufacturing method of steel strip with few surface defects - Google Patents

Manufacturing method of steel strip with few surface defects Download PDF

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JP4453299B2
JP4453299B2 JP2003292742A JP2003292742A JP4453299B2 JP 4453299 B2 JP4453299 B2 JP 4453299B2 JP 2003292742 A JP2003292742 A JP 2003292742A JP 2003292742 A JP2003292742 A JP 2003292742A JP 4453299 B2 JP4453299 B2 JP 4453299B2
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steel strip
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rolled steel
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勝 三宅
永晴 松澤
保博 曽谷
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JFE Steel Corp
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本発明は、熱延鋼帯の表層部に存在する製鋼性の介在物や疵などの表面欠陥に起因して発生する、冷延鋼帯やめっき鋼帯の表面欠陥を低減させるための鋼帯の製造方法に関するものである。   The present invention relates to a steel strip for reducing surface defects of a cold-rolled steel strip and a plated steel strip, which are caused by surface defects such as steel-making inclusions and flaws existing in the surface layer portion of the hot-rolled steel strip. It is related with the manufacturing method.

スラブから冷延鋼帯が得られるまでの通常の薄板製造プロセスでは、鋳造されたスラブを熱間圧延工程にて減厚して所定の板厚の熱延鋼帯とし、次いで、各々バッチ式の酸洗ラインと冷間圧延ラインにおいて、若しくは酸洗工程と冷間圧延工程とが連続化された酸洗・冷延連続ラインにおいて、まず、熱延鋼帯表面の酸化スケール層を酸洗(塩酸等の強酸による酸洗)で溶解除去し、しかる後、冷間での複数回の圧延パスを経て所定の板厚の冷延鋼帯に減厚される。また、用途によっては、冷延鋼帯に亜鉛めっき、錫めっきなどのめっき処理が施される。   In a normal thin plate manufacturing process from slab to cold-rolled steel strip, the cast slab is reduced in thickness by a hot rolling process to obtain a hot-rolled steel strip of a predetermined thickness. In the pickling line and the cold rolling line, or in the pickling / cold rolling continuous line in which the pickling process and the cold rolling process are continuous, first, the oxide scale layer on the surface of the hot rolled steel strip is pickled (hydrochloric acid). It is removed by dissolution by pickling with a strong acid such as, and then, after a plurality of cold rolling passes, the steel sheet is reduced to a cold-rolled steel strip having a predetermined thickness. Depending on the application, the cold-rolled steel strip is subjected to a plating treatment such as galvanization and tin plating.

上記のようにして製造される冷延鋼帯やめっき鋼帯には、鋳造スラブ自体に起因するもの、熱間圧延工程に起因するもの、酸洗、冷間圧延、表面処理などの工程に起因するものなど、様々な要因に基づく様々な形態の表面欠陥が発生する。このように発生要因が種々多様である表面欠陥に対し、根本的にはその発生要因を断つことが重要であるが、一方において、一旦発生した表面欠陥を冷間圧延以前のプロセスにおいて除去することができれば、それも有効な欠陥防止対策になり得る。従来、この種の欠陥防止対策として、例えば、以下のような方法が提案されている。   The cold-rolled steel strip and the plated steel strip manufactured as described above are caused by the casting slab itself, the hot rolling process, the pickling, the cold rolling, the surface treatment, etc. Various forms of surface defects occur due to various factors such as In this way, it is important to fundamentally cut off the generation of surface defects with various factors. On the other hand, once the surface defects are generated, they must be removed in the process before cold rolling. If possible, it can be an effective defect prevention measure. Conventionally, for example, the following methods have been proposed as this type of defect prevention measure.

(a) 冷間圧延ラインの入側において、鋼帯に生じている表面欠陥、特にヘゲと呼ばれるラップ状の欠陥を検出し、この検出情報にもとづいてヘゲ部分のみをインラインで切削除去する方法(例えば、特許文献1参照)。この方法では、切削手段として切削バイト、フライス形式の回転式切削装置、超音波切削装置などを用い、冷間圧延機群の直前にて冷延原板の表層を数十〜数百ミクロン除去する。また、切削装置はボールネジ等を用いて幅方向送りを行うことにより、鋼帯全面について欠陥除去が可能であるとしている。また、鋼帯表面上に部分的に生成された切削痕は、その直後の冷間圧延工程での減厚により完全に消去するとしている。
(b) バッチ式の酸洗ラインの酸洗槽出側において、鋼帯の表裏面の疵の位置と大きさを検出してその情報を記憶し、その後、バッチ式の冷間圧延ラインの圧延機入側において、前記検出疵情報に基づいて表面疵を除去する方法(例えば、特許文献2参照)。
(a) On the entrance side of the cold rolling line, surface defects generated in the steel strip, especially wrap-like defects called scabs, are detected, and only the scabs are cut and removed inline based on this detection information. Method (for example, refer to Patent Document 1). In this method, a cutting tool, a milling rotary cutter, an ultrasonic cutter, or the like is used as a cutting means, and the surface layer of the cold-rolled original sheet is removed by several tens to several hundreds of microns immediately before the cold rolling mill group. In addition, the cutting device is said to be able to remove defects on the entire surface of the steel strip by feeding in the width direction using a ball screw or the like. Moreover, it is supposed that the cutting traces partially generated on the surface of the steel strip are completely erased by the thickness reduction in the cold rolling process immediately after that.
(b) At the outlet side of the pickling tank of the batch type pickling line, the position and size of the wrinkles on the front and back surfaces of the steel strip are detected and stored, and then the rolling of the batch type cold rolling line is performed. A method of removing surface wrinkles based on the detected wrinkle information on the machine entry side (see, for example, Patent Document 2).

特開2001−191206号公報JP 2001-191206 A 特開昭61−219403号公報Japanese Patent Laid-Open No. 61-219403

上記従来技術は、欠陥除去部において切削や研削により生じた痕跡(以下、「欠陥除去痕」という)、すなわち微小な窪み状の痕跡は、冷間圧延における減厚により消滅することを前提としているものと考えられ(特許文献1にはその旨の記載がある)、欠陥除去痕が製品鋼帯の表面品質に何らかの影響を与える可能性については、何も考慮していない。   The above prior art is based on the premise that traces generated by cutting or grinding in the defect removal portion (hereinafter referred to as “defect removal traces”), that is, minute dent-like traces disappear due to thickness reduction in cold rolling. (There is a description to that effect in Patent Document 1), and no consideration is given to the possibility that the defect removal traces have any influence on the surface quality of the product steel strip.

しかし、本発明者らが実験により確認したところによれば、従来技術の方法によって板厚方向の比較的深い位置(例えば、深さ50μm以上)にある欠陥を除去した際に生じる欠陥除去痕は、その後の冷間圧延でも完全には消失せず、冷間圧延した後も非欠陥除去部との板厚の差或いは表面肌の違い(板厚の微妙な違いによる肌差)となって残ることが判った。また、一般に冷延圧延に引き続き或いはめっき後にダルロールを用いた調質圧延(伸張率数%以下の軽圧下圧延)が施され、鋼帯面或いはめっき面に所望の表面粗さが付与されるが、上記のように欠陥除去部と非欠陥除去部との板厚に差がある場合、板厚が薄い部分(欠陥除去部)ではダルロール表面の凹凸の転写が弱くなり、極端な場合にはロール表面と鋼帯面が全く接触せず、外観上の光沢ムラを発生させる要因となることが判った。   However, according to what the present inventors have confirmed through experiments, defect removal traces generated when a defect at a relatively deep position in the thickness direction (for example, a depth of 50 μm or more) is removed by a conventional method is as follows. Even after the subsequent cold rolling, it does not disappear completely, and even after cold rolling, it remains as a difference in plate thickness or surface skin (skin difference due to subtle difference in plate thickness) from the non-defect removal part. I found out. In general, temper rolling using a dull roll (light rolling at a stretch rate of several% or less) is applied subsequent to cold rolling or after plating, and a desired surface roughness is imparted to the steel strip surface or plated surface. As mentioned above, when there is a difference in the plate thickness between the defect removal portion and the non-defect removal portion, the transfer of unevenness on the surface of the dull roll is weak in the thin portion (defect removal portion), and in extreme cases, the roll It was found that the surface and the steel strip surface do not come into contact at all, which causes the appearance of uneven gloss.

また、欠陥除去によって部分的に板厚の薄くなった鋼帯部分に複雑な形状のプレス成形が施されると、加工中に板厚が薄い部分での応力が大きくなるため、その部分の板厚がより一層減少し、極端な場合には破断や穴あきなどを生じる恐れがあることも判った。
以上のように、従来技術において比較的深い欠陥除去を行った場合、製品鋼帯の外観ムラやプレス成形などの2次加工後の製品欠陥を発生させることが判った。
In addition, if a steel strip that has been partially thinned by removing defects is subjected to press molding with a complicated shape, the stress at the thin part during processing increases, so the plate at that part It has also been found that the thickness is further reduced, and in extreme cases, there is a risk of breakage or perforation.
As described above, it has been found that, when relatively deep defect removal is performed in the prior art, product defects after secondary processing such as uneven appearance of the product steel strip and press forming are generated.

したがって本発明の目的は、熱延鋼帯の表面欠陥を除去することにより生じる欠陥除去痕によって、製品鋼帯(冷延鋼帯またはめっき鋼帯)の表面品質の低下やプレス成形などの2次加工に伴う問題を生じることがなく、優れた品質及び性能を有する製品鋼帯を安定して製造することができる鋼帯の製造方法を提供することにある。   Therefore, the object of the present invention is to reduce the surface quality of the product steel strip (cold-rolled steel strip or plated steel strip) or to perform secondary molding such as press forming due to the defect removal marks generated by removing the surface defects of the hot-rolled steel strip. An object of the present invention is to provide a method of manufacturing a steel strip that can stably produce a product steel strip having excellent quality and performance without causing problems associated with processing.

本発明者らは、上記課題を解決するための方策を見出すべく種々の実験と検討を行ったが、その一連の実験の過程において、鋼帯の表面欠陥部を同じ欠陥除去深さで除去した場合でも、製品鋼帯面に欠陥除去痕に起因した外観ムラが生じる場合と生じない場合があるという事実を見い出した。そこで、表面品質にこのような差が生じる原因について詳細な検討を行ったところ、ある程度までの深さの欠陥除去部に関しては、冷間圧延において欠陥除去痕が製品鋼帯の表面品質を劣化させない程度まで解消(消去)されるかどうかは、欠陥除去深さと欠陥除去幅(=鋼帯幅方向での欠陥除去幅)と冷間圧延における鋼帯の圧下率の3者の関係により相対的に決まることが判った。具体的には、所定の欠陥除去深さに対して冷間圧延での圧下率に応じて欠陥除去幅に上限を設けることにより、或いは所定の欠陥除去幅に対して冷間圧延での圧下率に応じて欠陥除去深さに上限を設けることにより、冷間圧延において欠陥除去痕が製品鋼帯の表面品質を劣化させない程度まで解消(消去)されることが判った。
本発明は、以上のような知見に基づきなされたもので、その特徴は以下のとおりである。
The present inventors conducted various experiments and examinations to find out measures for solving the above-mentioned problems. In the course of the series of experiments, the surface defect portion of the steel strip was removed at the same defect removal depth. Even in this case, the present inventors have found the fact that the product steel strip may or may not have uneven appearance due to defect removal marks. Therefore, a detailed study was conducted on the cause of such a difference in surface quality. As for the defect removal part having a depth of a certain degree, the defect removal trace does not deteriorate the surface quality of the product steel strip in cold rolling. Whether or not it is eliminated (erased) to a certain extent is relatively determined by the relationship between the defect removal depth and the defect removal width (= defect removal width in the steel strip width direction) and the reduction ratio of the steel strip in cold rolling. I knew that it would be decided. Specifically, by setting an upper limit on the defect removal width in accordance with the rolling reduction ratio in the cold rolling for a predetermined defect removal depth, or the rolling reduction ratio in the cold rolling with respect to the predetermined defect removal width. Accordingly, it has been found that by setting an upper limit on the defect removal depth according to the above, the defect removal traces are eliminated (erased) to the extent that the surface quality of the product steel strip is not deteriorated in cold rolling.
The present invention has been made based on the above findings, and the features thereof are as follows.

[1]熱延鋼帯を冷間圧延して冷延鋼帯を製造し、若しくは前記冷間圧延して得られた冷延鋼帯をめっき処理してめっき鋼帯を製造する、鋼帯の製造方法において、
酸洗槽が設置されたラインで熱延鋼帯を連続通板させ、前記酸洗槽入側において、欠陥検出装置により熱延鋼帯の表面欠陥部を検出し、その欠陥検出信号に基づき、前記欠陥検出装置の下流側に設置された欠陥除去装置により前記表面欠陥部を除去し、しかる後、熱延鋼帯を前記酸洗槽で酸洗処理し、
前記欠陥検出装置による表面欠陥部の検出と前記欠陥除去装置による表面欠陥部の除去は、酸洗槽入側に配置されたブライドルロール装置を構成する入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(但し、入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して実施し、且つ、
前記表面欠陥部の検出・除去工程では、製品鋼帯に外観ムラを生じさせない表面欠陥部の欠陥除去深さ及び欠陥除去幅を予め求めておき、これに基づいて欠陥除去深さと欠陥除去幅を設定し、表面欠陥部の除去を行うことを特徴とする表面欠陥の少ない鋼帯の製造方法。
[1] Cold-rolling a hot-rolled steel strip to produce a cold-rolled steel strip, or plating a cold-rolled steel strip obtained by the cold rolling to produce a plated steel strip. In the manufacturing method,
The hot-rolled steel strip is continuously passed through the line where the pickling tank is installed, and on the entrance side of the pickling tank, the surface defect portion of the hot-rolled steel strip is detected by a defect detection device, based on the defect detection signal, The surface defect portion is removed by a defect removing device installed on the downstream side of the defect detecting device, and then the hot-rolled steel strip is pickled in the pickling tank,
The detection of the surface defect portion by the defect detection device and the removal of the surface defect portion by the defect removal device are performed between the entry-side bridle roll and the exit-side bridle roll constituting the bridle roll device arranged on the pickling tank entry side. For the steel strip portion (including the steel strip portion wound around the entry side bridle roll and the exit side bridle roll), and
In the step of detecting and removing the surface defect portion, the defect removal depth and the defect removal width of the surface defect portion that does not cause the appearance unevenness in the product steel strip are obtained in advance, and based on this, the defect removal depth and the defect removal width are determined. A method for producing a steel strip with few surface defects, characterized in that the surface defect portion is removed by setting.

[2]熱延鋼帯を冷間圧延して冷延鋼帯を製造し、若しくは前記冷間圧延して得られた冷延鋼帯をめっき処理してめっき鋼帯を製造する、鋼帯の製造方法において、
酸洗槽が設置されたラインで熱延鋼帯を連続通板させ、前記酸洗槽入側において、欠陥検出装置により熱延鋼帯の表面欠陥部を検出し、その欠陥検出信号に基づき、前記欠陥検出装置の下流側に設置された欠陥除去装置により前記表面欠陥部を除去し、しかる後、熱延鋼帯を前記酸洗槽で酸洗処理し、
前記欠陥検出装置による表面欠陥部の検出と前記欠陥除去装置による表面欠陥部の除去は、酸洗槽入側に配置されたブライドルロール装置を構成する入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(但し、入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して実施し、且つ、
前記表面欠陥部の検出・除去工程では、下記(1)式を満足する欠陥除去深さΔH及び欠陥除去幅Wで表面欠陥部を除去することを特徴とする表面欠陥の少ない鋼帯の製造方法。
ΔH≦α(h/H)×{(H−h)/Wβ} …(1)
但し ΔH:欠陥除去深さ(μm)
W:欠陥除去幅(mm)
H:冷間圧延前の鋼帯板厚(mm)
h:冷間圧延後の鋼帯板厚(mm)
α,β:定数
[2] Cold-rolling a hot-rolled steel strip to produce a cold-rolled steel strip, or plating a cold-rolled steel strip obtained by the cold rolling to produce a plated steel strip. In the manufacturing method,
The hot-rolled steel strip is continuously passed through the line where the pickling tank is installed, and on the entrance side of the pickling tank, the surface defect portion of the hot-rolled steel strip is detected by a defect detection device, based on the defect detection signal, The surface defect portion is removed by a defect removing device installed on the downstream side of the defect detecting device, and then the hot-rolled steel strip is pickled in the pickling tank,
The detection of the surface defect portion by the defect detection device and the removal of the surface defect portion by the defect removal device are performed between the entry-side bridle roll and the exit-side bridle roll constituting the bridle roll device arranged on the pickling tank entry side. For the steel strip portion (including the steel strip portion wound around the entry side bridle roll and the exit side bridle roll), and
In the surface defect portion detection / removal step, the surface defect portion is removed with a defect removal depth ΔH and a defect removal width W that satisfy the following expression (1): .
ΔH ≦ α (h / H) × {(H−h) / W β } (1)
ΔH: Defect removal depth (μm)
W: Defect removal width (mm)
H: Steel strip thickness before cold rolling (mm)
h: Steel strip thickness after cold rolling (mm)
α, β: Constant

本発明によれば、熱延鋼帯の表面欠陥を除去することにより生じる欠陥除去痕によって、製品鋼帯(冷延鋼帯またはめっき鋼帯)の表面品質の低下やプレス成形などの2次加工に伴う問題が生じることがなく、優れた品質及び性能を有する製品鋼帯を安定して製造することができる。   According to the present invention, due to the defect removal trace generated by removing the surface defects of the hot-rolled steel strip, secondary processing such as deterioration of the surface quality of the product steel strip (cold-rolled steel strip or plated steel strip) and press forming. Therefore, the product steel strip having excellent quality and performance can be stably produced.

本発明法では、鋼帯の地鉄表面に露出した欠陥部だけの検出及び除去を行う場合と、鋼帯の地鉄表面に露出した欠陥部だけでなく、鋼帯の地鉄表面に露出することなく地鉄表層部中に存在する欠陥部を含めた鋼帯地鉄表面−表層部に存在する欠陥部の検出及び除去を行う場合とがあり、したがって、本発明法において検出及び除去される熱延鋼帯の“表面欠陥部”とは、「鋼帯の地鉄表面に露出した欠陥部」又は「鋼帯の地鉄表面に露出した欠陥部と、鋼帯の地鉄表面に露出することなく地鉄表層部中に存在する欠陥部とを含めた鋼帯地鉄表面−表層部に存在する欠陥部」を意味するものとする。
本発明の鋼帯の製造方法では、熱延鋼帯を冷間圧延して冷延鋼帯を製造し、若しくは前記冷間圧延して得られた冷延鋼帯をめっき処理してめっき鋼帯を製造するに際し、熱延鋼帯が連続通板する任意のラインにおいて、欠陥検出装置により熱延鋼帯の表面欠陥部を検出し、その欠陥検出信号に基づき、前記欠陥検出装置の下流側に設置された欠陥除去装置により熱延鋼帯の前記表面欠陥部を除去する。
In the method of the present invention, when detecting and removing only the defective portion exposed on the surface of the steel strip, and not only the defective portion exposed on the surface of the steel strip, but also exposed to the surface of the steel strip. In some cases, the surface of the steel strip including the defect existing in the surface layer portion of the iron-steel without detecting the defect existing in the surface layer and removing the defect is detected in the method of the present invention. “Surface defects” on the steel strip means “defects exposed on the surface of the steel strip” or “defects exposed on the surface of the steel strip and the surface of the steel strip. It shall mean “the surface of the steel strip including the defective portion existing in the surface layer portion of the steel plate minus the defective portion existing in the surface layer portion”.
In the steel strip manufacturing method of the present invention, the hot-rolled steel strip is cold-rolled to produce a cold-rolled steel strip, or the cold-rolled steel strip obtained by the cold rolling is plated and plated steel strip. In the arbitrary line through which the hot-rolled steel strip passes continuously, the surface defect portion of the hot-rolled steel strip is detected by the defect detection device, and on the downstream side of the defect detection device based on the defect detection signal. The said surface defect part of a hot-rolled steel strip is removed with the installed defect removal apparatus.

以下、本発明を実施するための設備構成の例と、この設備構成を用いて行われる表面欠陥部の検出・除去の基本形態について説明する。
図1は、本発明を実施するための設備構成の一例と、この設備構成を用いて行われる表面欠陥部の検出・除去の基本形態を示すものであり、この例は、バッチ式の酸洗ラインにおいて、酸洗槽4の入側に、上流側から順に欠陥検出装置1と欠陥除去装置2を配置し、表面欠陥の検出と除去を行うようにしたものである。その他、図において、3は欠陥除去装置の制御装置、7はペイオフリール、8は巻取リール、9はトラッキングロールである。
Hereinafter, an example of an equipment configuration for carrying out the present invention and a basic form of detection / removal of a surface defect portion performed using the equipment configuration will be described.
FIG. 1 shows an example of an equipment configuration for carrying out the present invention and a basic form of detection / removal of a surface defect portion performed using the equipment configuration. This example is a batch type pickling. In the line, the defect detection device 1 and the defect removal device 2 are arranged in order from the upstream side on the entry side of the pickling tank 4 to detect and remove surface defects. In addition, in the figure, 3 is a control device for the defect removing device, 7 is a payoff reel, 8 is a take-up reel, and 9 is a tracking roll.

前記欠陥検出装置1の検出方式には特別な制限はなく、光学方式や画像処理方式でもよいが、熱延鋼帯の表層下に存在するヘゲ疵等を確実に検出するという面で、渦流方式、漏洩磁束方式などの磁気方式のセンサーが望ましい。この磁気式センサーを用いた欠陥検出装置は、例えば、鋼帯の交流励磁を行うと同時に、表面欠陥に起因して発生する交流磁束の変化を検出することで表面欠陥部を検出するものを用いることができる。このような欠陥検出装置の具体例としては、鋼帯を交流磁化し、磁束を鋼帯の略幅方向に並べて設けられた2以上の磁気センサで検出し、検出信号の鋼帯幅方向の差分信号に基づき表面欠陥部の検出を行う欠陥検出装置が挙げられる。このような欠陥検出装置によれば、鋼帯を交流磁束によって磁化するため、直流磁化を用いる場合に較べて表皮効果の影響により磁束の浸透深さが制限され、鋼帯の表層部近くに集中することになる。このため鋼帯の表面または表層部に存在する表面欠陥部のみを効率よく検出することができる。
欠陥検出装置1は、鋼帯6の両面の表面欠陥を検出できるよう、連続通板する鋼帯両面に対向して配置される。
The detection method of the defect detection device 1 is not particularly limited and may be an optical method or an image processing method. However, in the aspect of reliably detecting the hail and the like existing under the surface layer of the hot-rolled steel strip, A magnetic type sensor such as a magnetic flux type or a magnetic flux leakage type is desirable. The defect detection apparatus using this magnetic sensor uses, for example, an apparatus that detects a surface defect portion by detecting a change in AC magnetic flux generated due to a surface defect at the same time as performing AC excitation of a steel strip. be able to. As a specific example of such a defect detection device, the steel strip is AC magnetized, the magnetic flux is detected by two or more magnetic sensors arranged in the substantially width direction of the steel strip, and the difference between the detection signals in the steel strip width direction is detected. There is a defect detection device that detects a surface defect portion based on a signal. According to such a defect detection apparatus, since the steel strip is magnetized by AC magnetic flux, the penetration depth of the magnetic flux is limited by the effect of the skin effect compared to the case where DC magnetization is used, and concentrated near the surface layer portion of the steel strip. Will do. For this reason, only the surface defect part which exists in the surface or surface layer part of a steel strip can be detected efficiently.
The defect detection device 1 is disposed so as to face both surfaces of the steel strip that is continuously passed through so as to detect surface defects on both surfaces of the steel strip 6.

前記欠陥除去装置2の欠陥除去手段に特別な制限はなく、例えば、研削砥石、切削バイト、研削ブラシ、フライス形式の回転式切削刃、超音波切削装置、アブレシブジェット(金属粉などの微小固体粉を含む高速・高圧水の噴射による研削手段)など、任意の手段を用いることができ、また、異なる種類の欠陥除去手段を組み合わせて使用してもよいが、加工能率の面では研削砥石または切削バイトが有利である。   There is no particular limitation on the defect removal means of the defect removal apparatus 2, for example, a grinding wheel, cutting tool, grinding brush, milling rotary cutter, ultrasonic cutting apparatus, abrasive jet (fine solid powder such as metal powder) Any means can be used, such as high-speed, high-pressure water-injected grinding means), and different types of defect-removing means may be used in combination. Bite is advantageous.

欠陥除去手段は、連続通板する鋼帯の表面に局部的に存在する表面欠陥部を研削又は切削により部分的に除去するものであるため、鋼帯面に対して接離可能(鋼帯面に直交する方向で移動可能)であるとともに鋼帯幅方向で移動可能であり、さらに好ましくは、表面欠陥の深さに対応するため、鋼帯厚さ方向での押し込み量の調整が可能となっている。   The defect removal means removes the surface defect part that exists locally on the surface of the steel strip that is continuously passed through by grinding or cutting. And can be moved in the width direction of the steel strip, and more preferably, the amount of indentation in the thickness direction of the steel strip can be adjusted to cope with the depth of the surface defect. ing.

図1の実施形態では、ペイオフリール7から繰り出された熱延鋼帯6の表面欠陥部が欠陥検出装置1で検出され、その欠陥検出信号に基づき欠陥除去装置2において表面欠陥部の除去が行われる。この際、欠陥除去装置2の欠陥除去手段は、欠陥除去装置2からの表面欠陥部の位置情報(鋼帯幅方向での位置情報)に基づき、除去すべき表面欠陥部の鋼帯幅方向位置に応じて鋼帯幅方向で移動するとともに、トラッキングロール9により表面欠陥部の鋼帯搬送方向位置が検出されているので、トラッキングロール9の出力に基づく動作タイミングで鋼帯面に作用(研削、切削など)し、表面欠陥部の除去を行う。
欠陥除去装置2により表面欠陥部が除去された熱延鋼帯6は、酸洗槽4に導入されて酸洗された後、コイラー8に巻き取られ、次いで、次工程である冷間圧延ラインに送られ、そこで所定の厚さまで圧延され、冷延鋼帯が得られる。また、場合によって、この冷延鋼帯にはめっき処理が施され、めっき鋼帯が製造される。
In the embodiment of FIG. 1, the surface defect portion of the hot-rolled steel strip 6 fed out from the payoff reel 7 is detected by the defect detection device 1, and the surface defect portion is removed by the defect removal device 2 based on the defect detection signal. Is called. At this time, the defect removing means of the defect removing apparatus 2 uses the position information of the surface defect portion from the defect removing apparatus 2 (position information in the steel strip width direction) and the position of the surface defect portion to be removed in the steel strip width direction. Accordingly, the tracking roll 9 detects the position of the surface defect portion in the steel strip conveyance direction, so that it acts on the steel strip surface at the operation timing based on the output of the tracking roll 9 (grinding, Cutting), and removing the surface defect.
The hot-rolled steel strip 6 from which the surface defect portion has been removed by the defect removing device 2 is introduced into the pickling tank 4 and pickled, and then wound around the coiler 8, and then the cold rolling line as the next step. And rolled to a predetermined thickness to obtain a cold-rolled steel strip. In some cases, this cold-rolled steel strip is subjected to a plating treatment to produce a plated steel strip.

図2は、本発明を実施するための設備構成の他の例を示すものであり、この例は、酸洗設備と冷間圧延設備が連続して設けられた連続製造ライン(酸洗・冷延連続ライン)において、酸洗槽4の入側に、上流側から順に欠陥検出装置1と欠陥除去装置2を配置し、表面欠陥の検出と除去を行うようにしたものである。図において、5は酸洗槽4の下流側に設置された冷間圧延機群であり、その他の構成は図1と同様であるので、同一の符号を付し、詳細な説明は省略する。また、この実施形態における欠陥検出装置1と欠陥除去装置2の構成及び機能なども、図1の実施形態と同様である。この実施形態では、酸洗槽4を出た熱延鋼帯6はそのまま冷間圧延機群5で圧延され、冷延鋼帯が製造される。また、場合によって、この冷延鋼帯にはめっき処理が施され、めっき鋼帯が製造される。   FIG. 2 shows another example of the equipment configuration for carrying out the present invention. This example shows a continuous production line (pickling / cooling) in which pickling equipment and cold rolling equipment are continuously provided. In the continuous continuous line), the defect detection device 1 and the defect removal device 2 are arranged in order from the upstream side on the entrance side of the pickling tank 4 to detect and remove surface defects. In the figure, reference numeral 5 denotes a cold rolling mill group installed on the downstream side of the pickling tank 4, and other configurations are the same as those in FIG. Further, the configurations and functions of the defect detection apparatus 1 and the defect removal apparatus 2 in this embodiment are the same as those in the embodiment of FIG. In this embodiment, the hot-rolled steel strip 6 exiting the pickling tank 4 is rolled as it is in the cold rolling mill group 5 to produce a cold-rolled steel strip. In some cases, this cold-rolled steel strip is subjected to a plating treatment to produce a plated steel strip.

本発明では、以上のような基本形態で表面欠陥部の検出・除去を行うものであるが、その際に、製品鋼帯に外観ムラを生じさせない表面欠陥部の欠陥除去深さ及び欠陥除去幅を予め求めておき、これに基づいて欠陥除去装置による欠陥除去深さと欠陥除去幅を設定し、欠陥除去を行う。また、好ましくは、下記(1)式を満足する欠陥除去深さΔH及び欠陥除去幅Wで表面欠陥部の除去を行う。
ΔH≦α(h/H)×{(H−h)/Wβ} …(1)
但し ΔH:欠陥除去深さ(μm)
W:欠陥除去幅(mm)
H:冷間圧延前の鋼帯板厚(mm)
h:冷間圧延後の鋼帯板厚(mm)
α,β:定数
In the present invention, the surface defect portion is detected and removed in the basic form as described above. At that time, the defect removal depth and the defect removal width of the surface defect portion that do not cause the appearance unevenness in the product steel strip. Is determined in advance, and based on this, the defect removal depth and defect removal width by the defect removal apparatus are set, and defect removal is performed. Preferably, the surface defect portion is removed with a defect removal depth ΔH and a defect removal width W that satisfy the following expression (1).
ΔH ≦ α (h / H) × {(H−h) / W β } (1)
ΔH: Defect removal depth (μm)
W: Defect removal width (mm)
H: Steel strip thickness before cold rolling (mm)
h: Steel strip thickness after cold rolling (mm)
α, β: Constant

図3(a)は欠陥除去部の鋼帯幅方向断面、同図(b)は欠陥除去部を冷間圧延した後の鋼帯幅方向断面をそれぞれ示しており、以下の説明における欠陥除去深さΔH、欠陥除去幅W、欠陥除去部の冷間圧延後のへこみ深さΔhを図中に示してある。
図4は、板厚3.2mm、板幅1800mmの熱延鋼帯の表面欠陥部を欠陥除去深さΔH:50μm、欠陥除去幅W:10〜50mmで除去した後、表1に示す5パスのタンデム冷間圧延のスケジュールにて板厚0.792mmの冷延鋼帯に圧延した場合について、圧延後の欠陥除去部のへこみ深さΔhの各圧延パスでの推移を示している。
FIG. 3A shows a cross section in the steel strip width direction of the defect removing portion, and FIG. 3B shows a cross section in the steel strip width direction after cold rolling of the defect removing portion. The depth ΔH, the defect removal width W, and the dent depth Δh after the cold rolling of the defect removal portion are shown in the figure.
FIG. 4 shows 5 passes shown in Table 1 after removing surface defect portions of a hot-rolled steel strip having a plate thickness of 3.2 mm and a plate width of 1800 mm at a defect removal depth ΔH: 50 μm and a defect removal width W: 10-50 mm. In the case of rolling into a cold-rolled steel strip having a thickness of 0.792 mm according to the tandem cold rolling schedule, the transition of the indentation depth Δh of the defect removal portion after rolling in each rolling pass is shown.

図4によれば、欠陥除去幅Wが50mm程度では、へこみ深さΔhは略圧下率なりに変形し、圧延によって板厚が半分に減厚されれば、へこみ深さΔhも略半分の深さになるように変形している。これに対して欠陥除去幅Wが30mm程度以下では、へこみ深さΔhが欠陥除去幅Wの減少に伴って大きく低減している。また、欠陥除去幅Wを狭くした際のへこみ深さΔhの低減効果は1パス目が特に大きく、3パス目以降ではへこみ深さΔhは略圧下率なりに変形している。   According to FIG. 4, when the defect removal width W is about 50 mm, the dent depth Δh is deformed to be approximately a reduction ratio, and if the plate thickness is reduced by half by rolling, the dent depth Δh is also approximately half the depth. It is deformed to become. On the other hand, when the defect removal width W is about 30 mm or less, the dent depth Δh is greatly reduced as the defect removal width W decreases. In addition, the effect of reducing the dent depth Δh when the defect removal width W is narrowed is particularly great in the first pass, and the dent depth Δh is deformed substantially to a reduction rate after the third pass.

上記のように欠陥除去幅Wを狭くした場合にへこみ深さΔhが減少する理由について、へこみ深さΔhの低減効果が大きい冷間圧延の1パス目を例に検討した。図5〜図7は、欠陥除去幅Wが各々10mm(図5)、30mm(図6)、50mm(図7)の欠陥除去部について、表1に示した圧延スケジュールで圧延した場合における第1圧延パス後の欠陥除去部のへこみ深さΔhを示したものであり、また、図8は、同じく欠陥除去部周辺部の板幅方向歪εの分布を示したものである。 The reason why the dent depth Δh is reduced when the defect removal width W is reduced as described above was examined by taking the first pass of cold rolling, which has a large effect of reducing the dent depth Δh, as an example. 5 to 7 show the first case where the defect removal width W is 10 mm (FIG. 5), 30 mm (FIG. 6), and 50 mm (FIG. 7), respectively, when rolling is performed according to the rolling schedule shown in Table 1. The indentation depth Δh of the defect removal portion after the rolling pass is shown, and FIG. 8 also shows the distribution of the plate width direction strain ε W in the periphery of the defect removal portion.

図5〜図7によれば、圧延前は矩形形状であった欠陥除去部は、1パス後にはなだらかなへこみ形状となる。これは、欠陥除去部は周辺部に較べて圧延前の板厚が薄いため、圧延中に局所的な圧延方向の大きな引っ張り応力が発生し、その結果、欠陥除去部周辺の圧延圧力が低下することにより圧延ロールの表面偏平変形がなだらかに推移するためであると考えられる。へこみ深さΔhは、欠陥除去部の幅方向中心部にて最大となり、欠陥除去幅Wが50mmでは略圧下率なりに変形し、欠陥除去幅Wが10mmではその1/3程度にまで低減している。   According to FIGS. 5-7, the defect removal part which was a rectangular shape before rolling becomes a gentle dent shape after 1 pass. This is because the defect-removed part has a thinner plate thickness before rolling than the peripheral part, so a large tensile stress in the local rolling direction is generated during rolling, and as a result, the rolling pressure around the defect-removed part decreases. This is considered to be because the surface flattening deformation of the rolling roll gradually changes. The indentation depth Δh is maximum at the center in the width direction of the defect removal portion, and is deformed to a substantially reduction rate when the defect removal width W is 50 mm, and is reduced to about 1/3 when the defect removal width W is 10 mm. ing.

また、図8によれば、板幅方向歪εは、欠陥除去幅Wが50mmの場合には欠陥除去部の幅方向中心部にて略0となっており、材料の横流れがない状態、すなわち圧下歪が全て長手方向歪となる平面歪状態となっている。これに対して欠陥除去幅Wが10mmの場合には、欠陥除去部の略全幅に亘って板幅方向歪εが幅縮まりの方向となっており、欠陥除去部の体積不足分を補うために、圧延中に欠陥除去部周辺の材料が欠陥除去部に向かって横流れをしていることが判る。つまり、欠陥除去幅Wを狭くすることにより冷間圧延後のへこみ深さΔhが小さくなるメカニズムは、圧延ロールの弾性変形と材料の横流れ作用との兼ね合いにより、欠陥除去部の略全幅に亘って材料の横れが生じるためであると考えられる。したがって、このようなメカニズムによるへこみ深さΔhの低減化の程度は、圧延の圧下率にも依存し、さらに圧延ロール径、圧延ロール材質、被圧延材の材質等にも影響される。例えば、材料の横流れを促進するという面では圧延ロール径を大きくすることが好ましく、また、圧延ロールの表面偏平変形の分布を小さくするという面ではロール硬度を硬くすることが好ましく、特に1パス目の圧延ロールにおける効果が大きい。 Further, according to FIG. 8, the plate width direction strain ε W is substantially 0 at the center in the width direction of the defect removal portion when the defect removal width W is 50 mm, and there is no lateral flow of material. In other words, all the rolling strains are in the plane strain state in which the longitudinal strain is the longitudinal strain. On the other hand, when the defect removal width W is 10 mm, the plate width direction strain ε W is in the direction of width reduction over substantially the entire width of the defect removal portion, so as to compensate for the insufficient volume of the defect removal portion. In addition, it can be seen that the material around the defect removal portion is laterally flowing toward the defect removal portion during rolling. In other words, the mechanism by which the dent depth Δh after cold rolling is reduced by reducing the defect removal width W is substantially the entire width of the defect removal portion due to the balance between the elastic deformation of the rolling roll and the lateral flow action of the material. This is thought to be due to the material falling. Therefore, the degree of the reduction of the dent depth Δh by such a mechanism depends on the rolling reduction ratio, and is also affected by the rolling roll diameter, the rolling roll material, the material of the material to be rolled, and the like. For example, it is preferable to increase the diameter of the rolling roll in terms of promoting the lateral flow of the material, and it is preferable to increase the roll hardness in terms of reducing the distribution of surface flattening deformation of the rolling roll, particularly in the first pass. The effect on the rolling rolls is great.

図9は、欠陥除去幅Wが10〜50mm、欠陥除去深さΔHが各々25μm、50μm、100μmの欠陥除去部について、表1に示した5パスの圧延スケジュールで冷間圧延した後のへこみ深さΔhと、この冷延鋼板を合金化亜鉛めっきした後の外観ムラの発生の有無を調べた結果を示している。図9によれば、先に述べたように、へこみ深さΔhは欠陥除去寸法(欠陥除去幅W、欠陥除去深さΔH)に大きく影響されていることが判る。また、へこみ深さΔhが一定レベル以下ではめっき鋼帯には外観ムラは発生しておらず、欠陥除去幅Wと欠陥除去深さΔHとの関係では、欠陥除去深さΔHが50μmの場合には欠陥除去幅Wが略30mm以下において、また、欠陥除去深さΔHが100μmの場合には欠陥除去幅Wが略10mm以下において、それぞれ外観ムラは発生していない。
したがって、この図9に示されるような製品鋼帯に外観ムラを生じさせない欠陥除去深さΔH及び欠陥除去幅Wを予め求めておき、これに基づいて欠陥除去深さΔHと欠陥除去幅Wを設定し、欠陥除去を行うことにより、外観ムラのない製品鋼帯を得ることができる。
FIG. 9 shows the depth of dent after cold rolling with a 5-pass rolling schedule shown in Table 1 for a defect removal portion having a defect removal width W of 10 to 50 mm and a defect removal depth ΔH of 25 μm, 50 μm, and 100 μm, respectively. And Δh, and the results of examining the occurrence of unevenness in appearance after galvanizing this cold-rolled steel sheet. As can be seen from FIG. 9, the dent depth Δh is greatly influenced by the defect removal dimension (defect removal width W, defect removal depth ΔH), as described above. Further, when the dent depth Δh is below a certain level, the appearance of the plated steel strip is not uneven, and the relationship between the defect removal width W and the defect removal depth ΔH is that when the defect removal depth ΔH is 50 μm. No defect unevenness occurs when the defect removal width W is about 30 mm or less, and when the defect removal depth ΔH is 100 μm, the defect removal width W is about 10 mm or less.
Therefore, a defect removal depth ΔH and a defect removal width W that do not cause appearance unevenness in the product steel strip as shown in FIG. 9 are obtained in advance, and based on this, the defect removal depth ΔH and the defect removal width W are determined. By setting and removing defects, a product steel strip with no uneven appearance can be obtained.

図9の結果から、冷間圧延後のへこみ深さΔhは下記(A)式にて近似できることが判った。
Δh=α´Wβ´・ΔH …(A)
但し ΔH:欠陥除去深さ(μm)
W:欠陥除去幅(mm)
α´,β´:被圧延材の材質及び圧延条件に応じて決まる定数
また、図4の結果からして、冷間圧延後のへこみ深さΔhは総圧下率に略反比例し、また、外観ムラとならない閾値は冷間圧延後のへこみ深さΔhと冷間圧延後の鋼帯板厚hの比率に依存する。
From the results of FIG. 9, it was found that the dent depth Δh after cold rolling can be approximated by the following equation (A).
Δh = α′W β ′ · ΔH (A)
ΔH: Defect removal depth (μm)
W: Defect removal width (mm)
α ′, β ′: Constants determined according to the material and rolling conditions of the material to be rolled From the results of FIG. 4, the dent depth Δh after cold rolling is approximately inversely proportional to the total rolling reduction, and the appearance The threshold value at which unevenness does not occur depends on the ratio of the depth of recess Δh after cold rolling and the steel strip thickness h after cold rolling.

本発明者らは、上記の点を前提として数多くの実験を行い、その結果に基づいて、製品鋼帯に外観ムラを生じさせない欠陥除去寸法(欠陥除去深さΔH、欠陥除去幅W)の条件を見出すべく検討を行った。その結果、欠陥除去深さΔHと欠陥除去幅Wが下記(1)式を満足するように表面欠陥部の除去を行えば、製品鋼帯の外観ムラの発生を適切に防止できることが判った。この(1)式の技術的意義は、後述する実施例において明らかになる。
ΔH≦α(h/H)×{(H−h)/Wβ} …(1)
但し ΔH:欠陥除去深さ(μm)
W:欠陥除去幅(mm)
H:冷間圧延前の鋼帯板厚(mm)
h:冷間圧延後の鋼帯板厚(mm)
α,β:定数
The present inventors have conducted a number of experiments on the premise of the above points, and based on the results, conditions for defect removal dimensions (defect removal depth ΔH, defect removal width W) that do not cause appearance unevenness in the product steel strip. We examined to find out. As a result, it has been found that if the surface defect portion is removed so that the defect removal depth ΔH and the defect removal width W satisfy the following formula (1), occurrence of uneven appearance of the product steel strip can be prevented appropriately. The technical significance of the formula (1) will be clarified in examples described later.
ΔH ≦ α (h / H) × {(H−h) / W β } (1)
ΔH: Defect removal depth (μm)
W: Defect removal width (mm)
H: Steel strip thickness before cold rolling (mm)
h: Steel strip thickness after cold rolling (mm)
α, β: Constant

ここで、α,βは被圧延材の材質と圧延条件により定まる定数である。上述したように冷間圧延後のへこみ深さΔhは、圧延ロール径、圧延ロール材質などの冷間圧延条件と鋼帯の材質の影響を受ける。また、本発明者らによる実験の結果では、外観ムラの発生はへこみ深さΔhと調質圧延での伸張率の影響を受け、冷間圧延後のへこみ深さΔhと板厚hとの比Δh/hが調質圧延における伸張率e以下であれば欠陥除去部は製品鋼帯の外観ムラにならないことが判った。通常、冷延鋼帯やこれをめっき処理した鋼帯は材質調整と鋼帯への光沢付与のため、数%以下の伸張率にて調質圧延が行われる。この際、圧延ロール表面が扁平変形するため、多少のへこみが残存していても圧延ロールとの接触状態が保たれる。したがって、α、βは被圧延材の材質と圧延条件(冷間圧延での圧延ロール径や圧延ロール材質、調質圧延での伸張率など)に応じて決められる。   Here, α and β are constants determined by the material of the material to be rolled and the rolling conditions. As described above, the indentation depth Δh after the cold rolling is affected by the cold rolling conditions such as the rolling roll diameter and the rolling roll material and the material of the steel strip. Further, as a result of experiments by the present inventors, the occurrence of unevenness in appearance is affected by the dent depth Δh and the elongation ratio in temper rolling, and the ratio between the dent depth Δh after cold rolling and the sheet thickness h. It was found that if Δh / h is equal to or less than the elongation ratio e in temper rolling, the defect-removed portion does not cause uneven appearance of the product steel strip. Usually, temper rolling is performed at a stretch rate of several percent or less for the cold-rolled steel strip and the steel strip plated with the steel strip to adjust the material and impart luster to the steel strip. At this time, since the surface of the rolling roll is deformed flat, the contact state with the rolling roll is maintained even if some dent remains. Therefore, α and β are determined according to the material of the material to be rolled and the rolling conditions (rolling roll diameter and rolling roll material in cold rolling, elongation rate in temper rolling, etc.).

欠陥除去幅Wは、欠陥の発生状況(欠陥幅)、研削砥石などの欠陥除去手段の剛性の問題、欠陥除去手段の鋼帯幅方向での位置決め精度の問題などの面からはなるべく広いことが好ましいが、例えば本発明では、表面欠陥の発生状況(欠陥深さ)から目標欠陥除去深さを決定し、その深さと冷間圧延前後の板厚から上記(1)式に基づいて欠陥除去幅W(工具幅)を決定する。なお、この際の目標欠陥除去深さと欠陥除去幅は、欠陥の発生状況から上記(1)式に基づいて適宜変更してもよい。
先に述べたように、上記(1)式における定数α、βは被圧延材の材質と圧延条件に応じて決められるものであるが、一般的な被圧延材の材質と圧延条件を前提とした場合には、500≦α≦2000、0.6≦β≦0.7程度の範囲となる。
また、欠陥除去部は非除去部に比べて板厚が薄いことから、冷間圧延中に周辺の非欠陥除去部との間に伸び変形差が生じ、欠陥除去部に大きな引張り応力が作用することになる。この際、極端な場合には欠陥除去部に亀裂が発生し、この亀裂が圧延機間張力等により拡大して板幅全体の破断事故につながることもある。このような問題は欠陥除去深さΔHが大きいほど生じやすく、このため欠陥除去深さΔHは150μm程度以下、より好ましくは100μm程度以下とすることが望ましい。
The defect removal width W may be as wide as possible in terms of the occurrence of defects (defect width), the problem of rigidity of defect removal means such as a grinding wheel, and the problem of positioning accuracy of the defect removal means in the steel strip width direction. Preferably, for example, in the present invention, the target defect removal depth is determined from the occurrence state (defect depth) of surface defects, and the defect removal width is calculated based on the above equation (1) from the depth and the plate thickness before and after cold rolling. W (tool width) is determined. Note that the target defect removal depth and the defect removal width at this time may be appropriately changed based on the above equation (1) from the state of occurrence of defects.
As described above, the constants α and β in the above equation (1) are determined according to the material and rolling conditions of the material to be rolled, and are based on the general material and rolling conditions of the material to be rolled. In this case, the range is about 500 ≦ α ≦ 2000 and 0.6 ≦ β ≦ 0.7.
In addition, since the thickness of the defect-removed part is thinner than that of the non-removed part, a difference in elongation and deformation occurs between the non-defect removed part in the vicinity during cold rolling, and a large tensile stress acts on the defect-removed part. It will be. At this time, in an extreme case, a crack is generated in the defect removing portion, and this crack may be expanded due to the tension between rolling mills and the like, leading to a fracture accident of the entire sheet width. Such a problem is more likely to occur as the defect removal depth ΔH is larger. For this reason, the defect removal depth ΔH is desirably about 150 μm or less, more preferably about 100 μm or less.

次に、連続ライン中において表面欠陥部の検出と除去を行う位置について、好ましい実施形態を説明する。
本発明による表面欠陥の検出と除去は、熱延鋼帯が連続通板する任意のラインで行うことができる。すなわち、コイル検査ライン、酸洗ライン、冷間圧延ライン、酸洗工程と冷間圧延工程が連続した酸洗・冷延連続ラインなど、熱間圧延工程以降、冷間圧延工程以前の任意の段階で行うことができるが、特に、鋼帯に張力を付与するためのブライドルロール装置を有するラインにおいて行われることが好ましい。このようなブライドルロール装置が設けられたラインでは、鋼帯に適度な張力が付与されているため、板形状不良などによる板面の変動が小さく、表面欠陥の検出や除去を高精度に安定して行うことができる利点がある。
Next, a preferred embodiment will be described with respect to the position where the surface defect portion is detected and removed in the continuous line.
Detection and removal of surface defects according to the present invention can be performed in any line through which a hot-rolled steel strip is continuously passed. That is, any stage after the hot rolling process and before the cold rolling process, such as coil inspection line, pickling line, cold rolling line, pickling / cold rolling continuous line where pickling process and cold rolling process are continuous In particular, it is preferably performed in a line having a bridle roll device for applying tension to the steel strip. In a line equipped with such a bridle roll device, an appropriate tension is applied to the steel strip, so fluctuations in the plate surface due to plate shape defects and the like are small, and surface defect detection and removal is stabilized with high accuracy. There are advantages that can be done.

また、複数のブライドルロールからなるブライドルロール装置内の鋼帯部分は、板形状不良や振動などによる板面の変動が特に小さい。このためブライドルロール装置内で表面欠陥検出と表面欠陥除去を行うこと、すなわち、ブライドルロール装置の入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して表面欠陥検出と表面欠陥除去を実施することにより、板形状不良や振動などによる板面の変動の影響を受けることなく、表面欠陥検出と表面欠陥除去を高精度且つ安定的に行うことができる。   In addition, the steel strip portion in the bridle roll device composed of a plurality of bridle rolls has particularly small fluctuations in the plate surface due to plate shape defects or vibrations. For this reason, surface defect detection and surface defect removal are performed in the bridle roll device, that is, the steel strip portion between the entry side bridle roll and the exit side bridle roll (entrance side bridle roll and exit side bridle roll). By detecting surface defects and removing surface defects (including steel strips wrapped around), surface defect detection and surface defect removal are not affected by variations in the plate surface due to plate shape defects or vibrations. Can be performed with high accuracy and stability.

さらに、ブライドルロール装置内では、鋼帯は装置を構成する複数のブライドルロールに対して表裏面が交互に巻き付いた状態で通板するが、この各ブライドルロールに巻き付いた鋼帯部分は板形状不良や振動などによる板面の変動が最も小さく、したがって、この鋼帯部分に対して表面欠陥の検出と除去を実施することにより、それらを特に高精度且つ安定的に行うことができ、しかも、鋼帯表裏面に対して欠陥検出装置や欠陥除去装置の配置がしやすく、且つ加工屑の処理もしやすいなどの利点もある。   Furthermore, in the bridle roll device, the steel strip passes through the bridle rolls that make up the device with the front and back surfaces alternately wound, but the steel strip portion wound around each bridle roll has a poor plate shape. The fluctuation of the plate surface due to vibration and vibration is the smallest. Therefore, by detecting and removing surface defects on this steel strip part, they can be performed with particularly high accuracy and stability. There are also advantages such as easy arrangement of the defect detection device and defect removal device on the front and back surfaces of the belt and easy processing of the processing waste.

図10は、ブライドルロール装置11の位置に欠陥検出装置1と欠陥除去装置2を配置した場合の一実施形態を示している。なお、この実施形態は、欠陥除去装置2の欠陥除去手段として研削砥石12を用いたものである。
本実施形態のブライドルロール装置11は4ロール式であり、熱延鋼帯6は4本のブライドルロール110a〜110dに対して表裏面が交互に巻き付いた状態で通板する。鋼帯表裏面の表面欠陥を検出するための欠陥検出装置1a,1b(検出センサ)は、上流側の2本のブライドルロール110a,110bに各々対向して配置され、ブライドルロール110a,110bに巻き付いた鋼帯部分(鋼帯の表裏面)の表面欠陥を検出する。
FIG. 10 shows an embodiment in which the defect detection device 1 and the defect removal device 2 are arranged at the position of the bridle roll device 11. In this embodiment, a grinding wheel 12 is used as the defect removing means of the defect removing apparatus 2.
The bridle roll device 11 of the present embodiment is a four-roll type, and the hot-rolled steel strip 6 passes through the four bridle rolls 110a to 110d with the front and back surfaces wound alternately. Defect detection devices 1a and 1b (detection sensors) for detecting surface defects on the front and back surfaces of the steel strip are arranged opposite to the two upstream bridle rolls 110a and 110b, and are wound around the bridle rolls 110a and 110b. Detects surface defects in steel strip parts (front and back surfaces of steel strip).

一方、欠陥除去装置2の欠陥除去手段である研削砥石12a,12bは、下流側の2本のブライドルロール110c,110dの側方位置においてロールに各々対向して配置され、上記欠陥検出装置1a,1bによる欠陥検出に基づいて、ブライドルロール110c,110dに巻き付いた鋼帯部分(鋼帯の表裏面)の表面欠陥部を研削除去する。この研削砥石12a,12bは、移動機構(押し込み機構)によりブライドルロール110c,110d方向に対して進退可能であり、除去すべき表面欠陥部がある鋼帯部分が通板してきた際にブライドルロール110c,110d方向に移動し、表面欠陥部の部分的な研削除去を行う。なお、研削砥石12a,12bの鋼帯幅方向での移動・位置調整機構については後述する(図14の説明)。   On the other hand, the grinding wheels 12a and 12b, which are defect removal means of the defect removal apparatus 2, are respectively arranged facing the rolls at the side positions of the two bridle rolls 110c and 110d on the downstream side, and the defect detection apparatus 1a, Based on the defect detection by 1b, the surface defect portion of the steel strip portion (front and back surfaces of the steel strip) wound around the bridle rolls 110c and 110d is ground and removed. The grinding wheels 12a and 12b can be moved back and forth in the direction of the bridle rolls 110c and 110d by a moving mechanism (pushing mechanism), and when the steel strip portion having a surface defect portion to be removed passes through the bridle roll 110c. , 110d, and partially grind and remove the surface defect portion. The movement / position adjustment mechanism of the grinding wheels 12a and 12b in the steel strip width direction will be described later (description of FIG. 14).

ブライドルロール装置において、ブライドルロールに巻き付いた鋼帯部分に対して表面欠陥検出と表面欠陥除去を行う形態は任意であり、上記実施形態に限定されるものではない。例えば、図10に示すような4ロール式のブライドルロール装置において、入側の2本のブライドルロール又は出側の2本のブライドルロールの位置で表面欠陥検出と表面欠陥除去を行ってもよい。図11はその一実施形態を示すもので、ブライドルロール装置の入側の2本のブライドルロール110a,110bに巻き付いた鋼帯部分に対して表面欠陥検出と表面欠陥除去を行う場合を示している。
この実施形態では、鋼帯おもて面の表面欠陥を検出するための欠陥検出装置1a(検出センサ)と欠陥除去装置2の欠陥除去手段である研削砥石12aが、ブライドルロール装置11の入側の第1のブライドルロール110aに各々対向して順次配置され、欠陥検出装置1aによりブライドルロール110aに巻き付いた鋼帯部分(鋼帯のおもて面)の表面欠陥を検出し、その検出に基づき、直ちに研削砥石12aが表面欠陥部を研削除去する。また、鋼帯裏面の表面欠陥を検出するための欠陥検出装置1b(検出センサ)と欠陥除去装置2の欠陥除去手段である研削砥石12bが、第2のブライドルロール110bに各々対向して順次配置され、欠陥検出装置1bによりブライドルロール110bに巻き付いた鋼帯部分(鋼帯の裏面)の表面欠陥を検出し、その検出に基づき、直ちに研削砥石12bが表面欠陥部を研削除去する。
In the bridle roll apparatus, the form of performing surface defect detection and surface defect removal on the steel strip portion wound around the bridle roll is arbitrary, and is not limited to the above embodiment. For example, in a 4-roll bridle roll apparatus as shown in FIG. 10, surface defect detection and surface defect removal may be performed at the position of two bridle rolls on the entry side or two bridle rolls on the exit side. FIG. 11 shows the embodiment, and shows a case where surface defect detection and surface defect removal are performed on the steel strip portion wound around the two bridle rolls 110a and 110b on the entry side of the bridle roll apparatus. .
In this embodiment, a defect detection device 1a (detection sensor) for detecting surface defects on the front surface of the steel strip and a grinding wheel 12a that is a defect removal means of the defect removal device 2 are provided on the entry side of the bridle roll device 11. The surface defect of the steel strip portion (the front surface of the steel strip) that is sequentially arranged facing each of the first bridle rolls 110a and wound around the bridle roll 110a by the defect detection device 1a is detected, and based on the detection. Immediately, the grinding wheel 12a removes the surface defect by grinding. Further, a defect detection device 1b (detection sensor) for detecting a surface defect on the back surface of the steel strip and a grinding wheel 12b which is a defect removal means of the defect removal device 2 are sequentially arranged facing each of the second bridle rolls 110b. Then, a surface defect of the steel strip portion (back surface of the steel strip) wound around the bridle roll 110b is detected by the defect detection device 1b, and the grinding wheel 12b immediately removes the surface defect portion based on the detection.

また、3ロール方式や2ロール方式のブライドルロール装置のブライドルロールに巻き付いた鋼帯部分に対して表面欠陥検出と表面欠陥除去を行ってもよい。
図12は、3ロール方式のブライドルロール装置11のブライドルロールに巻き付いた鋼帯部分に対して表面欠陥検出と表面欠陥除去を行う場合を示している。この実施形態では、鋼帯おもて面の表面欠陥を検出するための欠陥検出装置1a(検出センサ)がブライドルロール装置11の第1のブライドルロール110aに、欠陥除去装置2の欠陥除去手段である研削砥石12aが第3のブライドルロール110cに各々対向して配置され、欠陥検出装置1aによりブライドルロール110aに巻き付いた鋼帯部分(鋼帯のおもて面)の表面欠陥を検出し、その検出に基づき、ブライドルロール110cに巻き付いた鋼帯部分について研削砥石12aが表面欠陥部を研削除去する。また、鋼帯裏面の表面欠陥を検出するための欠陥検出装置1b(検出センサ)と欠陥除去装置2の欠陥除去手段である研削砥石12bが第2のブライドルロール110bに各々対向して順次配置され、欠陥検出装置1bによりブライドルロール110bに巻き付いた鋼帯部分(鋼帯の裏面)の表面欠陥を検出し、その検出に基づき、直ちに研削砥石12bが表面欠陥部を研削除去する。
Further, surface defect detection and surface defect removal may be performed on a steel strip portion wound around a bridle roll of a 3-roll type or 2-roll type bridle roll device.
FIG. 12 shows a case where surface defect detection and surface defect removal are performed on the steel strip portion wound around the bridle roll of the three-roll type bridle roll apparatus 11. In this embodiment, the defect detection device 1a (detection sensor) for detecting surface defects on the steel strip front surface is replaced with the first bridle roll 110a of the bridle roll device 11 by the defect removal means of the defect removal device 2. A grinding wheel 12a is arranged opposite to each of the third bridle rolls 110c, and the surface detection of the steel strip portion (the front surface of the steel strip) wound around the bridle roll 110a is detected by the defect detection device 1a. Based on the detection, the grinding wheel 12a grinds away the surface defect portion of the steel strip portion wound around the bridle roll 110c. Further, a defect detection device 1b (detection sensor) for detecting a surface defect on the back surface of the steel strip and a grinding wheel 12b which is a defect removal means of the defect removal device 2 are sequentially arranged facing each of the second bridle rolls 110b. Then, the surface defect of the steel strip portion (back surface of the steel strip) wound around the bridle roll 110b is detected by the defect detection device 1b, and the grinding wheel 12b immediately removes the surface defect portion based on the detection.

図13は、2ロール方式のブライドルロール装置11のブライドルロールに巻き付いた鋼帯部分に対して表面欠陥検出と表面欠陥除去を行う場合を示している。この実施形態では、鋼帯おもて面の表面欠陥を検出するための欠陥検出装置1a(検出センサ)と欠陥除去装置2の欠陥除去手段である研削砥石12aが、ブライドルロール装置11の第1のブライドルロール110aに各々対向して順次配置され、欠陥検出装置1aによりブライドルロール110aに巻き付いた鋼帯部分(鋼帯のおもて面)の表面欠陥を検出し、その検出に基づき、直ちに研削砥石12aが表面欠陥部を研削除去する。また、鋼帯裏面の表面欠陥を検出するための欠陥検出装置1b(検出センサ)と欠陥除去装置2の欠陥除去手段である研削砥石12bが、第2のブライドルロール110bに各々対向して順次配置され、欠陥検出装置1bによりブライドルロール110bに巻き付いた鋼帯部分(鋼帯の裏面)の表面欠陥を検出し、その検出に基づき、直ちに研削砥石12bが表面欠陥部を研削除去する。
図10〜図13は、表面欠陥検出と表面欠陥除去をブライドルロール装置11を構成するブライドルロール110に巻き付いた鋼帯部分に対して実施するものであり、この方法が表面欠陥検出と表面欠陥除去を最も高精度且つ安定的に行うことができるが、場合によっては、ブライドルロール装置11を構成するブライドルロール110間の鋼帯部分に対して表面欠陥検出及び/又は表面欠陥除去を行ってもよい。
FIG. 13 shows a case where surface defect detection and surface defect removal are performed on the steel strip portion wound around the bridle roll of the two-roll type bridle roll apparatus 11. In this embodiment, the defect detection device 1a (detection sensor) for detecting surface defects on the front surface of the steel strip and the grinding wheel 12a that is the defect removal means of the defect removal device 2 are the first of the bridle roll device 11. The surface defect of the steel strip portion (the front surface of the steel strip), which is sequentially arranged facing each of the bridle rolls 110a and wound around the bridle roll 110a by the defect detection device 1a, is detected and immediately ground based on the detection. The grindstone 12a grinds away the surface defect portion. Further, a defect detection device 1b (detection sensor) for detecting a surface defect on the back surface of the steel strip and a grinding wheel 12b which is a defect removal means of the defect removal device 2 are sequentially arranged facing each of the second bridle rolls 110b. Then, a surface defect of the steel strip portion (back surface of the steel strip) wound around the bridle roll 110b is detected by the defect detection device 1b, and the grinding wheel 12b immediately removes the surface defect portion based on the detection.
10 to 13 show that surface defect detection and surface defect removal are performed on a steel strip portion wound around a bridle roll 110 constituting the bridle roll device 11, and this method is used for surface defect detection and surface defect removal. However, depending on the case, surface defect detection and / or surface defect removal may be performed on the steel strip portion between the bridle rolls 110 constituting the bridle roll device 11. .

なお、ブライドルロール装置11が複数基設置されている場合には、ライン上流側のブライドルロール装置11内で欠陥検出装置1による表面欠陥の検出(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の検出)を行い、次いで、下流側のブライドルロール装置11内で欠陥除去装置2による表面欠陥の除去(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の除去)を行ってもよい。また、ライン上流側のブライドルロール装置11内で、熱延鋼帯のおもて面側又は裏面側について欠陥検出装置1による表面欠陥の検出(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の検出)と欠陥除去装置2による表面欠陥の除去(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の除去)を行い、次いで、下流側のブライドルロール装置11内で、熱延鋼帯の反対側面について欠陥検出装置1による表面欠陥の検出(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の検出)と欠陥除去装置2による表面欠陥の除去(好ましくは、ブライドルロール110に巻き付いた鋼帯部分の表面欠陥の除去)を行ってもよい。これらの実施形態は、いずれも本発明法に含まれる。   When a plurality of bridle roll devices 11 are installed, detection of surface defects by the defect detection device 1 in the bridle roll device 11 on the upstream side of the line (preferably, a steel strip portion wound around the bridle roll 110) Detection of surface defects), and then removal of surface defects by the defect removal device 2 in the bridle roll device 11 on the downstream side (preferably, removal of surface defects on the steel strip portion wound around the bridle roll 110). Also good. Further, in the bridle roll device 11 on the upstream side of the line, detection of surface defects by the defect detection device 1 on the front surface side or back surface side of the hot rolled steel strip (preferably, the steel strip portion wound around the bridle roll 110) Detection of surface defects) and removal of surface defects by the defect removing device 2 (preferably, removal of surface defects in the steel strip portion wound around the bridle roll 110), and then, in the bridle roll device 11 on the downstream side, Detection of surface defects on the opposite side of the steel strip by the defect detection device 1 (preferably detection of surface defects in the steel strip portion wound around the bridle roll 110) and removal of surface defects by the defect removal device 2 (preferably bridle) (Removal of surface defects in the steel strip portion wound around the roll 110) may be performed. Any of these embodiments is included in the method of the present invention.

図14は、図10〜図13の実施形態における欠陥除去装置2の平面図である。この欠陥除去装置2は、鋼帯幅方向の一部領域を移動可能な研削砥石12又は切削バイト13(以下、ここでは「欠陥除去手段」という)を複数基備え、表面欠陥除去を鋼帯幅方向でこれら複数基の欠陥除去手段に分担させることにより、鋼帯全幅の表面欠陥除去を行えるようにしてある。この実施形態では、欠陥除去装置2は鋼帯幅方向で4つのセクションに分割され、各セクションに欠陥除去手段が備えられている。これら各欠陥除去手段は、各セクション内において鋼帯幅方向移動(横行移動)可能であり、駆動手段により移動する。このように鋼帯幅方向で複数基の欠陥除去手段を設け、各欠陥除去手段の鋼帯幅方向での移動距離を短くすることにより、連続通板する鋼帯面の表面欠陥の除去を確実かつ効率的に行うことができる。   FIG. 14 is a plan view of the defect removal apparatus 2 in the embodiment of FIGS. The defect removing apparatus 2 includes a plurality of grinding wheels 12 or cutting tools 13 (hereinafter referred to as “defect removing means”) that can move in a partial region in the steel strip width direction, and remove surface defects. The surface defect removal of the full width of the steel strip can be performed by sharing these plural defect removal means in the direction. In this embodiment, the defect removal apparatus 2 is divided into four sections in the steel strip width direction, and each section is provided with defect removal means. Each of these defect removal means can be moved in the width direction of the steel strip (transverse movement) in each section, and is moved by the driving means. In this way, by providing a plurality of defect removal means in the steel strip width direction and shortening the moving distance of each defect removal means in the steel strip width direction, it is possible to reliably remove surface defects on the steel strip surface that passes continuously. And can be performed efficiently.

通常、冷延鋼帯の板幅は最大でも2000mm程度であり、したがって、本実施形態のように欠陥除去装置2を鋼帯幅方向で4セクション程度に分割し、各々のセクションに欠陥除去手段を設置すれば、1つの欠陥除去手段は鋼帯幅方向で最大500mm程度の範囲で横行移動すればよく、効率的かつ確実な欠陥除去を行うことができる。欠陥除去装置2を鋼帯幅方向に幾つのセクションに分割するかは、表面欠陥の発生頻度、ライン速度、欠陥除去手段の鋼帯幅方向での送り速度、欠陥検出装置と欠陥除去装置間の距離などを勘案して決めればよい。   Usually, the plate width of the cold-rolled steel strip is about 2000 mm at the maximum. Therefore, the defect removing apparatus 2 is divided into about four sections in the steel strip width direction as in this embodiment, and defect removing means is provided in each section. If installed, one defect removing means may be traversed within a range of up to about 500 mm in the steel strip width direction, and efficient and reliable defect removal can be performed. The number of sections in which the defect removal device 2 is divided in the steel strip width direction depends on the occurrence frequency of surface defects, the line speed, the feed speed of the defect removal means in the steel strip width direction, between the defect detection device and the defect removal device. You only need to determine the distance.

各欠陥除去手段の鋼帯幅方向での移動機構(横行機構)は任意であり、例えば、横行用ボールネジとこれを回転させるモータなどからなる公知の機構等、適宜な機構を用いることができる。また、欠陥除去手段を鋼帯面に対し接離(移動)させるための機構も任意であり、例えば、欠陥除去手段をその横行機構ごとシリンダ装置で保持し、このシリンダ装置を駆動手段として欠陥除去手段を鋼帯面に対して接離動作させるような機構等、適宜な機構を用いることができる。
上記複数基の欠陥除去手段の鋼帯幅方向での移動や、鋼帯面方向への移動は、制御装置3(図1及び図2)により各々独立して制御され、これにより鋼帯面のどの位置の表面欠陥部であっても容易に除去することができる。すなわち、欠陥検出装置1の欠陥検知信号に基づいて、鋼帯幅方向における欠陥位置に相当するセクションの欠陥除去手段を鋼帯幅方向で欠陥位置まで移動させ、次いで欠陥除去手段を鋼帯面方向に移動させることにより、表面欠陥部の除去を容易に行うことができる。
The moving mechanism (transverse mechanism) in the steel strip width direction of each defect removing means is arbitrary, and for example, an appropriate mechanism such as a known mechanism including a traverse ball screw and a motor for rotating the traverse ball screw can be used. Also, the mechanism for moving the defect removing means to and from the steel strip surface is optional. For example, the defect removing means is held by the cylinder device together with its traversing mechanism, and this cylinder device is used as the driving means to remove the defect. An appropriate mechanism such as a mechanism for moving the means toward and away from the steel strip surface can be used.
The movement of the plurality of defect removing means in the steel strip width direction and the movement in the steel strip surface direction are independently controlled by the control device 3 (FIGS. 1 and 2), whereby the steel strip surface Any surface defect at any position can be easily removed. That is, based on the defect detection signal of the defect detection device 1, the defect removal means of the section corresponding to the defect position in the steel strip width direction is moved to the defect position in the steel strip width direction, and then the defect removal means is moved in the steel strip surface direction. The surface defect portion can be easily removed by moving to.

また、先に挙げた従来技術では、表面欠陥部の除去は冷間圧延の直前で行われているが、図1及び図2に示すように酸洗ラインの酸洗槽4入側において表面欠陥部の検出と除去を行い、しかる後、熱延鋼帯を酸洗槽4において酸洗処理することにより、酸洗による溶解作用によって欠陥除去痕の表面肌が改質され、しかも欠陥除去により生じた加工屑(この加工屑が製品鋼帯の表面に残存していると表面疵などの原因となる)の鋼帯面からの除去が確実になされるため、より優れた表面品質の製品鋼帯を得ることができる。酸洗設備は、熱延鋼帯を冷間圧延する前に鋼帯面の酸化スケール層を溶解除去するために設置されるもので、熱延鋼帯を冷間圧延する設備ではほぼ必須の設備である。したがって、この実施形態は、特別な設備を設置することなく酸洗設備という既存の設備を用いて実施できるという面でも有利な形態である。   Moreover, in the prior art mentioned above, although the removal of the surface defect part is performed immediately before cold rolling, as shown in FIG.1 and FIG.2, the surface defect in the pickling tank 4 entrance side of a pickling line Then, the hot rolled steel strip is pickled in the pickling tank 4, so that the surface skin of the defect removal trace is modified by the dissolving action by pickling, and is caused by the defect removal. The product strip with better surface quality can be reliably removed from the steel strip surface if the scrap is left on the surface of the product strip. Can be obtained. The pickling equipment is installed to dissolve and remove the oxide scale layer on the steel strip surface before cold rolling the hot rolled steel strip. It is almost essential equipment for cold rolling the hot rolled steel strip. It is. Therefore, this embodiment is also an advantageous form in that it can be implemented using existing equipment called pickling equipment without installing special equipment.

また、上記熱延鋼帯の酸洗は液温80℃以上の条件で行うことが好ましく、これにより鋼帯面の欠陥除去痕に対する溶解作用が高まり、欠陥除去痕の表面肌の改質をより効果的に行うことができる。なお、液温を95℃より高くしても鋼帯面の欠陥除去痕に対する溶解作用は飽和するため、液温を高温に保持するための蒸気などの原単位の低減の観点から、液温は95℃以下とすることが好ましい。
酸洗は、一般に塩酸系の酸洗液を用い、複数の塩酸槽にて行われる。各塩酸槽の塩酸濃度は、酸洗液を循環させるために異なる場合が多いが、その最も濃度の高い槽の塩酸濃度が6%以上であることが好ましく、これにより鋼帯面の欠陥除去痕に対する溶解作用を高めることができる。一方、塩酸濃度を11%より高くしても鋼帯面の欠陥除去痕に対する溶解作用は飽和するため、塩酸原単位低減の観点から、塩酸濃度は11%以下とすることがさらに好ましい。
なお、酸洗液としては、前記したように塩酸系の酸洗液が一般的であるが、硫酸系の酸洗液を用いることもできる。
また、以上述べた点からして、酸洗槽入側に配置されたブライドルロール装置の位置において、上記の実施形態により表面欠陥部の検出と除去を行うことが、最も好ましい実施形態であると言える。
In addition, the pickling of the hot-rolled steel strip is preferably performed at a liquid temperature of 80 ° C. or higher, thereby increasing the dissolving action on the defect removal traces on the steel strip surface, and further improving the surface skin of the defect removal traces. Can be done effectively. Even if the liquid temperature is higher than 95 ° C., the dissolution action on the defect removal traces on the steel strip surface is saturated. From the viewpoint of reducing the basic unit such as steam for keeping the liquid temperature at a high temperature, the liquid temperature is The temperature is preferably 95 ° C. or lower.
The pickling is generally performed in a plurality of hydrochloric acid tanks using a hydrochloric acid-based pickling solution. The concentration of hydrochloric acid in each hydrochloric acid tank is often different in order to circulate the pickling solution, but the concentration of hydrochloric acid in the tank with the highest concentration is preferably 6% or more, so that defect removal marks on the steel strip surface can be obtained. Can be enhanced. On the other hand, even if the hydrochloric acid concentration is higher than 11%, the dissolving action on the defect removal traces on the steel strip surface is saturated. Therefore, from the viewpoint of reducing the hydrochloric acid basic unit, the hydrochloric acid concentration is more preferably 11% or less.
As described above, the pickling solution is generally a hydrochloric acid-based pickling solution, but a sulfuric acid-based pickling solution can also be used.
Further, from the above points, it is most preferable embodiment to detect and remove the surface defect portion according to the above embodiment at the position of the bridle roll device arranged on the entrance side of the pickling tank. I can say that.

したがって、表面欠陥部の検出及び除去の位置について、本発明の好ましい実施形態をまとめると、以下のようになる。
(1) ブライドルロール装置を構成する入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(但し、入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して、欠陥検出装置による表面欠陥検出と欠陥除去装置による表面欠陥除去を実施する。
(2) 上記(1)において、ブライドルロール装置を構成するブライドルロールに巻き付いた鋼帯部分に対して、欠陥検出装置による表面欠陥検出と欠陥除去装置による表面欠陥除去を実施する。
(3) 鋼帯幅方向の一部領域を移動可能な欠陥除去手段を鋼帯幅方向で複数基備えた欠陥除去装置を用い、表面欠陥除去を鋼帯幅方向で前記複数基の欠陥除去手段に分担させることにより、鋼帯全幅の表面欠陥除去を行う。
(4) 上記(1)又は(2)において、鋼帯幅方向の一部領域を移動可能な欠陥除去手段を鋼帯幅方向で複数基備えた欠陥除去装置を用い、表面欠陥除去を鋼帯幅方向で前記複数基の欠陥除去手段に分担させることにより、鋼帯全幅の表面欠陥除去を行う。
また、上記(1)〜(4)の形態による表面欠陥の検出と除去を酸洗槽入側において行い、しかる後、熱延鋼帯を酸洗槽において酸洗すること、好ましくは上述した特定の条件で酸洗することが特に望ましい。
Therefore, the preferred embodiments of the present invention are summarized as follows for the detection and removal positions of the surface defect portion.
(1) For the steel strip portion between the entry-side bridle roll and the exit-side bridle roll constituting the bridle roll device (however, including the steel strip portion wound around the entry-side bridle roll and the exit-side bridle roll) Surface defect detection by a defect detection device and surface defect removal by a defect removal device are performed.
(2) In (1) above, surface defect detection by the defect detection device and surface defect removal by the defect removal device are performed on the steel strip portion wound around the bridle roll constituting the bridle roll device.
(3) Using a defect removal apparatus provided with a plurality of defect removal means movable in the steel strip width direction in the steel strip width direction, surface defect removal in the steel strip width direction using the plurality of defect removal means The surface defect removal of the full width of the steel strip is carried out by sharing the same.
(4) In the above (1) or (2), the surface defect removal is performed by using a defect removal apparatus provided with a plurality of defect removal means in the steel strip width direction that can move a partial region in the steel strip width direction The surface defect removal of the entire width of the steel strip is performed by sharing the plurality of defect removal means in the width direction.
In addition, detection and removal of surface defects in the forms (1) to (4) above are performed on the entrance side of the pickling tank, and then the hot-rolled steel strip is pickled in the pickling tank, preferably the above-described identification It is particularly desirable to perform pickling under the following conditions.

図2に示す酸洗・冷延連続ラインにおいて、図10に示すように酸洗槽4の直前のブライドルロール装置11に欠陥検出装置1と欠陥除去装置2を設置し、インラインでの熱延鋼帯の表面欠陥除去を行なった。熱延鋼帯は板厚3.2mm、板幅1500〜1800mmの自動車外板用のIF鋼である。
欠陥検出装置1では渦流式センサーを用いて欠陥検出を行った。欠陥除去装置1では、欠陥検出装置1からの欠陥検出信号に基づき、目標欠陥除去深さを20〜140μmの範囲で20μmピッチで変更し、また欠陥除去幅Wを10〜60mmの範囲で10mmピッチで変更し、外径φ400mm、粒度番号36番の研削砥石を使用して欠陥除去を行った。この欠陥除去後の熱延鋼帯を酸洗槽4で酸洗(酸洗槽前後のライン速度:平均150mpm)した後、冷間圧延、合金化亜鉛めっき及び調質圧延を順次行って製品鋼帯を製造した。本実施例の冷間圧延条件、調質圧延条件は下記の通りであり、上記(1)式における定数α、βの値は、α:766、β:0.6517である。
・冷間圧延条件 圧延ロール:φ500mm(全スタンド)
圧延パススケジュール:表1(5パス)
・調質圧延条件 伸張率:1%
In the continuous pickling / cold rolling line shown in FIG. 2, the defect detection device 1 and the defect removal device 2 are installed in the bridle roll device 11 immediately before the pickling tank 4 as shown in FIG. Strip surface defects were removed. The hot-rolled steel strip is IF steel for automobile outer plates having a plate thickness of 3.2 mm and a plate width of 1500 to 1800 mm.
In the defect detection apparatus 1, defect detection was performed using an eddy current sensor. In the defect removal apparatus 1, based on the defect detection signal from the defect detection apparatus 1, the target defect removal depth is changed at a pitch of 20 μm within a range of 20 to 140 μm, and the defect removal width W is a pitch of 10 mm within a range of 10 to 60 mm. The defect was removed using a grinding wheel having an outer diameter of 400 mm and a particle size number of 36. The hot-rolled steel strip after removal of the defects is pickled in the pickling tank 4 (line speed before and after the pickling tank: average 150 mpm), and then subjected to cold rolling, alloying galvanizing and temper rolling in order. A strip was manufactured. The cold rolling conditions and temper rolling conditions of this example are as follows, and the values of the constants α and β in the above equation (1) are α: 766 and β: 0.6517.
・ Cold rolling conditions Rolling roll: φ500mm (all stands)
Rolling pass schedule: Table 1 (5 passes)
-Conditioning rolling conditions Elongation rate: 1%

図15に、上記(1)式による外観ムラ発生限界線と欠陥除去痕に由来する製品鋼帯の外観ムラの発生状況を示す。同図から明らかなように、欠陥除去深さを上記(1)式による外観ムラ発生限界線よりも大きくした場合には、欠陥除去部が外観ムラとなるのに対し、欠陥除去深さを上記(1)式による外観ムラ発生限界線より小さくした場合には全く外観ムラは発生していない。   FIG. 15 shows the appearance of the appearance unevenness of the product steel strip derived from the appearance unevenness occurrence limit line and the defect removal trace according to the above equation (1). As is clear from the figure, when the defect removal depth is larger than the appearance unevenness occurrence limit line according to the above equation (1), the defect removal portion becomes the appearance unevenness, whereas the defect removal depth is When it is smaller than the appearance unevenness generation limit line according to the formula (1), no appearance unevenness occurs.

図2に示す酸洗・冷延連続ラインにおいて、図10に示すように酸洗槽4の直前のブライドルロール装置11に欠陥検出装置1と欠陥除去装置2を設置し、インラインでの熱延鋼帯の表面欠陥除去を行なった。熱延鋼帯は板厚2.8mm、板幅1500〜1800mmであって、材料硬度が実施例1の材料よりも約30%高いIF鋼である。
欠陥検出装置1では渦流式センサーを用いて欠陥検出を行った。欠陥除去装置1では、欠陥検出装置1からの欠陥検出信号に基づき、目標欠陥除去深さを20〜140μmの範囲で20μmピッチで変更し、また欠陥除去幅Wを10〜60mmの範囲で10mmピッチで変更し、外径φ400mm、粒度番号36番の研削砥石を使用して欠陥除去を行った。この欠陥除去後の熱延鋼帯を酸洗槽4で酸洗(酸洗槽前後のライン速度:平均150mpm)した後、冷間圧延、合金化亜鉛めっき及び調質圧延を順次行って製品鋼帯を製造した。本実施例の冷間圧延条件、調質圧延条件は下記の通りであり、上記(1)式における定数α、βの値は、α:1364、β:0.6517である。
・冷間圧延条件 圧延ロール:φ500mm(全スタンド)
圧延パススケジュール:表2(5パス)
・調質圧延条件 伸張率:2%
In the continuous pickling / cold rolling line shown in FIG. 2, the defect detection device 1 and the defect removal device 2 are installed in the bridle roll device 11 immediately before the pickling tank 4 as shown in FIG. Strip surface defects were removed. The hot-rolled steel strip is IF steel having a plate thickness of 2.8 mm, a plate width of 1500 to 1800 mm, and a material hardness of about 30% higher than that of the material of Example 1.
In the defect detection apparatus 1, defect detection was performed using an eddy current sensor. In the defect removal apparatus 1, based on the defect detection signal from the defect detection apparatus 1, the target defect removal depth is changed at a pitch of 20 μm within a range of 20 to 140 μm, and the defect removal width W is a pitch of 10 mm within a range of 10 to 60 mm. The defect was removed using a grinding wheel having an outer diameter of 400 mm and a particle size number of 36. The hot-rolled steel strip after removal of the defects is pickled in the pickling tank 4 (line speed before and after the pickling tank: average 150 mpm), and then subjected to cold rolling, alloying galvanizing and temper rolling in order. A strip was manufactured. The cold rolling conditions and temper rolling conditions of this example are as follows, and the values of constants α and β in the above equation (1) are α: 1364 and β: 0.6517.
・ Cold rolling conditions Rolling roll: φ500mm (all stands)
Rolling pass schedule: Table 2 (5 passes)
-Conditioning rolling conditions Elongation rate: 2%

図16に、上記(1)式による外観ムラ発生限界線と欠陥除去痕に由来する製品鋼帯の外観ムラの発生状況を示す。同図から明らかなように、欠陥除去深さを上記(1)式による外観ムラ発生限界線よりも大きくした場合には、欠陥除去部が外観ムラとなるのに対し、欠陥除去深さを上記(1)式による外観ムラ発生限界線より小さくした場合には全く外観ムラは発生していない。   FIG. 16 shows the appearance of the appearance unevenness of the product steel strip derived from the appearance unevenness occurrence limit line and the defect removal trace according to the above equation (1). As is clear from the figure, when the defect removal depth is larger than the appearance unevenness occurrence limit line according to the above equation (1), the defect removal portion becomes the appearance unevenness, whereas the defect removal depth is When it is smaller than the appearance unevenness generation limit line according to the formula (1), no appearance unevenness occurs.

図2に示す酸洗・冷延連続ラインにおいて、図10に示すように酸洗槽4の直前のブライドルロール装置11に欠陥検出装置1と欠陥除去装置2を設置し、インラインでの熱延鋼帯の表面欠陥除去を行なった。熱延鋼帯は、実施例1の材料と同じ板厚3.2mm、板幅1500〜1800mmの自動車外板用のIF鋼である。
欠陥検出装置1では渦流式センサーを用いて欠陥検出を行った。欠陥除去装置2では、欠陥検出装置1からの欠陥検出信号に基づき、目標欠陥除去深さを50μm、欠陥除去幅Wを10mm、50mmの2水準として、外径φ400mm、粒度番号36番の研削砥石を使用して欠陥除去を行った。この欠陥除去後の熱延鋼帯を酸洗槽4で酸洗(酸洗槽前後のライン速度:平均150mpm)した後、冷間圧延、合金化亜鉛めっき及び調質圧延を順次行って製品鋼帯を製造した。本実施例の冷間圧延条件、調質圧延条件は下記の通りであり、上記(1)式における定数α、βの値は、α:766、β:0.6517である。
・冷間圧延条件 圧延ロール:φ500mm(全スタンド)
圧延パススケジュール:表1(5パス)
・調質圧延条件 伸張率:1%
In the continuous pickling / cold rolling line shown in FIG. 2, the defect detection device 1 and the defect removal device 2 are installed in the bridle roll device 11 immediately before the pickling tank 4 as shown in FIG. Strip surface defects were removed. The hot-rolled steel strip is an IF steel for automobile outer plates having a plate thickness of 3.2 mm and a plate width of 1500 to 1800 mm, the same as the material of Example 1.
In the defect detection apparatus 1, defect detection was performed using an eddy current sensor. In the defect removal apparatus 2, based on the defect detection signal from the defect detection apparatus 1, a grinding wheel with an outer diameter of φ400 mm and a particle size number of 36 is set with two levels of a target defect removal depth of 50 μm and a defect removal width W of 10 mm and 50 mm. Was used to remove the defects. The hot-rolled steel strip after removal of the defects is pickled in the pickling tank 4 (line speed before and after the pickling tank: average 150 mpm), and then subjected to cold rolling, alloying galvanizing and temper rolling in order. A strip was manufactured. The cold rolling conditions and temper rolling conditions of this example are as follows, and the values of the constants α and β in the above equation (1) are α: 766 and β: 0.6517.
・ Cold rolling conditions Rolling roll: φ500mm (all stands)
Rolling pass schedule: Table 1 (5 passes)
-Conditioning rolling conditions Elongation rate: 1%

亜鉛めっき処理ラインの出側にて、1コイル毎に欠陥除去痕に由来する外観ムラを含めた表面欠陥の個数と長さをカウントし、全コイル長に対する総欠陥長さを不良率とした。
不良率は1週間分の調査結果を平均して1データとした。本実施例では、最初の10週間は熱延鋼帯の欠陥除去を全く行わず、その期間における10データの平均不良率を1.0とした。次の10週間では欠陥除去幅を10mmとした熱延鋼帯の欠陥除去を行い、さらに次の10週間では欠陥除去幅を50mmとした欠陥除去を行った。なお、定期的にサンプルを採取して冷間圧延後のへこみ深さを測定したところ、欠陥除去幅10mmでは冷間圧延後のへこみ深さは板厚の1%以下であり、欠陥除去幅50mmでは冷間圧延後のへこみ深さは板厚の1%以上であった。
図17に不良率の推移を示す。これによれば、欠陥除去幅10mmで欠陥除去を行った場合には、その前の欠陥除去を全く行わなかった場合に較べて不良率が1/5程度にまで低減した。一方、欠陥除去幅50mmで欠陥除去を行った場合には、欠陥除去痕に由来する外観ムラが多く観察された。
On the exit side of the galvanization processing line, the number and length of surface defects including appearance irregularities derived from defect removal traces were counted for each coil, and the total defect length relative to the total coil length was defined as the defect rate.
The defect rate was averaged from the survey results for one week to be one data. In this example, the defect removal of the hot-rolled steel strip was not performed at all for the first 10 weeks, and the average defect rate of 10 data in that period was set to 1.0. In the next 10 weeks, defects were removed from the hot-rolled steel strip with a defect removal width of 10 mm, and in the next 10 weeks, defects were removed with a defect removal width of 50 mm. In addition, when the sample was taken regularly and the dent depth after the cold rolling was measured, the dent depth after the cold rolling was 1% or less of the plate thickness at the defect removal width of 10 mm, and the defect removal width was 50 mm. Then, the dent depth after cold rolling was 1% or more of the plate thickness.
FIG. 17 shows the transition of the defect rate. According to this, when the defect removal was performed with the defect removal width of 10 mm, the defect rate was reduced to about 1/5 compared to the case where the previous defect removal was not performed at all. On the other hand, when defect removal was performed with a defect removal width of 50 mm, many appearance irregularities derived from defect removal traces were observed.

本発明は、自動車、家電製品、建材などに用いられる表面品質が優れた冷延鋼帯やめっき鋼帯を製造するために利用することができる。   INDUSTRIAL APPLICATION This invention can be utilized in order to manufacture the cold-rolled steel strip and the plated steel strip excellent in the surface quality used for a motor vehicle, a household appliance, a building material, etc.

本発明を実施するための設備構成の一例と、この設備構成を用いて行われる表面欠陥部の検出・除去の基本形態を示す説明図An explanatory diagram showing an example of the equipment configuration for carrying out the present invention and the basic form of detection / removal of a surface defect portion performed using this equipment configuration 本発明を実施するための設備構成の他の例と、この設備構成を用いて行われる表面欠陥部の検出・除去の基本形態を示す説明図Explanatory drawing which shows the other form of the equipment structure for implementing this invention, and the basic form of the detection / removal of the surface defect part performed using this equipment structure 熱延鋼帯の欠陥除去寸法(ΔH、W)と、欠陥除去部を冷間圧延した後のへこみ深さΔhを示す説明図Explanatory drawing which shows the dent depth (DELTA) h after cold-rolling the defect removal dimension ((DELTA) H, W) of a hot-rolled steel strip, and a defect removal part. 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合において、各圧延パス後の欠陥除去部のへこみ深さΔhの推移を示すグラフThe graph which shows transition of the dent depth (DELTA) h of the defect removal part after each rolling pass in the case of cold rolling after removing the surface defect of a hot-rolled steel strip 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合における、第1圧延パス後の欠陥除去部のへこみ深さΔhの一例を示す説明図Explanatory drawing which shows an example of dent depth (DELTA) h of the defect removal part after the 1st rolling pass in the case of performing cold rolling after performing the surface defect removal of a hot-rolled steel strip. 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合における、第1圧延パス後の欠陥除去部のへこみ深さΔhの他の例を示す説明図Explanatory drawing which shows the other example of dent depth (DELTA) h of the defect removal part after the 1st rolling pass in the case of performing cold rolling after performing the surface defect removal of a hot-rolled steel strip. 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合における、第1圧延パス後の欠陥除去部のへこみ深さΔhの他の例を示す説明図Explanatory drawing which shows the other example of dent depth (DELTA) h of the defect removal part after the 1st rolling pass in the case of performing cold rolling after performing the surface defect removal of a hot-rolled steel strip. 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合における、第1圧延パス後の欠陥除去部周辺部の板幅方向歪εの分布を示す説明図Explanatory drawing which shows distribution of sheet width direction distortion | strain (epsilon) W of the defect removal part periphery part after a 1st rolling pass in the case of performing cold rolling after performing the surface defect removal of a hot-rolled steel strip. 熱延鋼帯の表面欠陥除去を行った後に冷間圧延した場合における、欠陥除去部のへこみ深さΔhとめっき後の外観ムラの発生状況を欠陥除去幅Wとの関係で示すグラフThe graph which shows the generation | occurrence | production condition of the unevenness | corrugation depth Δh of a defect removal part, and the external appearance nonuniformity after plating in relation to the defect removal width W at the time of cold rolling after removing the surface defect of a hot-rolled steel strip 本発明の製造方法において、欠陥検出装置及び欠陥除去装置の実施形態の一例を示す説明図Explanatory drawing which shows an example of embodiment of a defect detection apparatus and a defect removal apparatus in the manufacturing method of this invention. 本発明の製造方法において、欠陥検出装置及び欠陥除去装置の実施形態の他の例を示す説明図Explanatory drawing which shows the other example of embodiment of a defect detection apparatus and a defect removal apparatus in the manufacturing method of this invention. 本発明の製造方法において、欠陥検出装置及び欠陥除去装置の実施形態の他の例を示す説明図Explanatory drawing which shows the other example of embodiment of a defect detection apparatus and a defect removal apparatus in the manufacturing method of this invention. 本発明の製造方法において、欠陥検出装置及び欠陥除去装置の実施形態の他の例を示す説明図Explanatory drawing which shows the other example of embodiment of a defect detection apparatus and a defect removal apparatus in the manufacturing method of this invention. 図10〜図13に示す欠陥除去装置の平面図Plan view of the defect removing apparatus shown in FIGS. 実施例1における製品鋼帯の外観ムラの発生状況を欠陥除去幅Wと欠陥除去深さΔHとの関係で示すグラフThe graph which shows the generation | occurrence | production state appearance irregularity of the product steel strip in Example 1 by the relationship between the defect removal width W and defect removal depth (DELTA) H. 実施例2における製品鋼帯の外観ムラの発生状況を欠陥除去幅Wと欠陥除去深さΔHとの関係で示すグラフThe graph which shows the generation | occurrence | production state of the appearance nonuniformity of the product steel strip in Example 2 by the relationship between the defect removal width W and the defect removal depth ΔH. 実施例3における製品鋼帯の不良率の推移を示すグラフThe graph which shows transition of the defect rate of the product steel strip in Example 3

符号の説明Explanation of symbols

1,1a,1b…欠陥検出装置
2…欠陥除去装置
3…制御装置
4…酸洗槽
5…冷間圧延機群
6…鋼帯
7…アンコイラー
8…コイラー
9…トラッキングロール
11…ブライドルロール装置
12a,12b…研削砥石
110a〜110d…ブライドルロール
DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Defect detection apparatus 2 ... Defect removal apparatus 3 ... Control apparatus 4 ... Pickling tank 5 ... Cold rolling mill group 6 ... Steel strip 7 ... Uncoiler 8 ... Coiler 9 ... Tracking roll 11 ... Bridle roll apparatus 12a , 12b ... Grinding wheels 110a to 110d ... Bridle roll

Claims (2)

熱延鋼帯を冷間圧延して冷延鋼帯を製造し、若しくは前記冷間圧延して得られた冷延鋼帯をめっき処理してめっき鋼帯を製造する、鋼帯の製造方法において、
酸洗槽が設置されたラインで熱延鋼帯を連続通板させ、前記酸洗槽入側において、欠陥検出装置により熱延鋼帯の表面欠陥部を検出し、その欠陥検出信号に基づき、前記欠陥検出装置の下流側に設置された欠陥除去装置により前記表面欠陥部を除去し、しかる後、熱延鋼帯を前記酸洗槽で酸洗処理し、
前記欠陥検出装置による表面欠陥部の検出と前記欠陥除去装置による表面欠陥部の除去は、酸洗槽入側に配置されたブライドルロール装置を構成する入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(但し、入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して実施し、且つ、
前記表面欠陥部の検出・除去工程では、製品鋼帯に外観ムラを生じさせない表面欠陥部の欠陥除去深さ及び欠陥除去幅を予め求めておき、これに基づいて欠陥除去深さと欠陥除去幅を設定し、表面欠陥部の除去を行うことを特徴とする表面欠陥の少ない鋼帯の製造方法。
In the manufacturing method of a steel strip, a cold-rolled steel strip is manufactured by cold rolling a hot-rolled steel strip, or a cold-rolled steel strip obtained by the cold rolling is plated to manufacture a plated steel strip. ,
The hot-rolled steel strip is continuously passed through the line where the pickling tank is installed, and on the entrance side of the pickling tank, the surface defect portion of the hot-rolled steel strip is detected by a defect detection device, based on the defect detection signal, The surface defect portion is removed by a defect removing device installed on the downstream side of the defect detecting device, and then the hot-rolled steel strip is pickled in the pickling tank,
The detection of the surface defect portion by the defect detection device and the removal of the surface defect portion by the defect removal device are performed between the entry-side bridle roll and the exit-side bridle roll constituting the bridle roll device arranged on the pickling tank entry side. For the steel strip portion (including the steel strip portion wound around the entry side bridle roll and the exit side bridle roll), and
In the step of detecting and removing the surface defect portion, the defect removal depth and the defect removal width of the surface defect portion that does not cause the appearance unevenness in the product steel strip are obtained in advance, and based on this, the defect removal depth and the defect removal width are determined. A method for producing a steel strip with few surface defects, characterized in that the surface defect portion is removed by setting.
熱延鋼帯を冷間圧延して冷延鋼帯を製造し、若しくは前記冷間圧延して得られた冷延鋼帯をめっき処理してめっき鋼帯を製造する、鋼帯の製造方法において、
酸洗槽が設置されたラインで熱延鋼帯を連続通板させ、前記酸洗槽入側において、欠陥検出装置により熱延鋼帯の表面欠陥部を検出し、その欠陥検出信号に基づき、前記欠陥検出装置の下流側に設置された欠陥除去装置により前記表面欠陥部を除去し、しかる後、熱延鋼帯を前記酸洗槽で酸洗処理し、
前記欠陥検出装置による表面欠陥部の検出と前記欠陥除去装置による表面欠陥部の除去は、酸洗槽入側に配置されたブライドルロール装置を構成する入側ブライドルロールと出側ブライドルロールとの間の鋼帯部分(但し、入側ブライドルロール及び出側ブライドルロールに巻き付いた鋼帯部分を含む)に対して実施し、且つ、
前記表面欠陥部の検出・除去工程では、下記(1)式を満足する欠陥除去深さΔH及び欠陥除去幅Wで表面欠陥部を除去することを特徴とする表面欠陥の少ない鋼帯の製造方法。
ΔH≦α(h/H)×{(H−h)/Wβ} …(1)
但し ΔH:欠陥除去深さ(μm)
W:欠陥除去幅(mm)
H:冷間圧延前の鋼帯板厚(mm)
h:冷間圧延後の鋼帯板厚(mm)
α,β:定数
In the manufacturing method of a steel strip, a cold-rolled steel strip is manufactured by cold rolling a hot-rolled steel strip, or a cold-rolled steel strip obtained by the cold rolling is plated to manufacture a plated steel strip. ,
The hot-rolled steel strip is continuously passed through the line where the pickling tank is installed, and on the entrance side of the pickling tank, the surface defect portion of the hot-rolled steel strip is detected by a defect detection device, based on the defect detection signal, The surface defect portion is removed by a defect removing device installed on the downstream side of the defect detecting device, and then the hot-rolled steel strip is pickled in the pickling tank,
The detection of the surface defect portion by the defect detection device and the removal of the surface defect portion by the defect removal device are performed between the entry-side bridle roll and the exit-side bridle roll constituting the bridle roll device arranged on the pickling tank entry side. For the steel strip portion (including the steel strip portion wound around the entry side bridle roll and the exit side bridle roll), and
In the surface defect portion detection / removal step, the surface defect portion is removed with a defect removal depth ΔH and a defect removal width W that satisfy the following expression (1): .
ΔH ≦ α (h / H) × {(H−h) / W β } (1)
ΔH: Defect removal depth (μm)
W: Defect removal width (mm)
H: Steel strip thickness before cold rolling (mm)
h: Steel strip thickness after cold rolling (mm)
α, β: Constant
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