JPH1147806A - Manufacture of black plate for electrogalvanizing - Google Patents
Manufacture of black plate for electrogalvanizingInfo
- Publication number
- JPH1147806A JPH1147806A JP20368997A JP20368997A JPH1147806A JP H1147806 A JPH1147806 A JP H1147806A JP 20368997 A JP20368997 A JP 20368997A JP 20368997 A JP20368997 A JP 20368997A JP H1147806 A JPH1147806 A JP H1147806A
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- Japan
- Prior art keywords
- rolling
- steel sheet
- cold
- plating
- 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.)
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- Metal Rolling (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電気亜鉛めっき鋼
板のめっき原板として使用される冷延鋼板の製造方法に
関し、詳しくは電気亜鉛めっき鋼板のめっき表面に現れ
る松葉状模様の発生を抑制防止し得るようにしたもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cold-rolled steel sheet used as a base material for electrogalvanized steel sheet, and more particularly to a method for suppressing the occurrence of a crutch pattern appearing on the plating surface of an electrogalvanized steel sheet. It is something that you get.
【０００２】[0002]
【従来の技術】電気亜鉛めっき鋼板のめっき原板とし
て、弱脱酸鋼，低炭素Ａｌキルド鋼等の低炭素鋼を熱間
圧延および冷間圧延して製造される鋼板が使用されてい
る。熱間圧延は、加熱炉から抽出されたスラブをシート
バーに減厚する粗圧延と、シートバーを所定板厚に減厚
圧延する仕上げ圧延の工程からなる。図５において、
（１）は粗圧延装置，（２）は仕上げ圧延装置である。
粗圧延装置（１）は２基の圧延機(R1)(R2)（前段圧延機
R1はリバース圧延機）からなり、仕上げ圧延装置（２）
は複数基の圧延機（図では７基の圧延機F1〜F7）をタン
デム配列した構成を有している。粗圧延装置（１）で
は、前段の圧延機(R1)による正方向パス（ａ）と逆方向
パス（ｂ）の正逆パス圧延が所定の回数（例えば,5〜7
回）繰返され、仕上げ圧延は圧延機（F1）〜（F7）によ
る１パス圧延により行われる。2. Description of the Related Art A steel sheet produced by hot rolling and cold rolling a low-carbon steel such as a weakly deoxidized steel and a low-carbon Al-killed steel is used as a base plate for electrogalvanized steel sheets. The hot rolling includes a rough rolling process of reducing the thickness of a slab extracted from a heating furnace into a sheet bar, and a finishing rolling process of reducing the thickness of the sheet bar to a predetermined thickness. In FIG.
(1) is a rough rolling device, and (2) is a finish rolling device.
Rough rolling mill (1) consists of two rolling mills (R1) (R2) (pre-mill
R1 consists of a reverse rolling mill) and a finishing rolling mill (2)
Has a configuration in which a plurality of rolling mills (seven rolling mills F1 to F7 in the figure) are arranged in tandem. In the rough rolling device (1), forward and reverse pass rolling of the forward pass (a) and the reverse pass (b) by the preceding rolling mill (R1) is performed a predetermined number of times (for example, 5 to 7).
The final rolling is performed by one-pass rolling using rolling mills (F1) to (F7).
【０００３】熱延工程の鋼材の表面にはスケールが生成
する。粗圧延では、鋼材温度が高く（約1100℃以上) 、
このためスケール生成は顕著である。スケールの成長応
力が鋼板表面との密着応力を越えると、図６（１）のよ
うに、スケール（Ｓ）にブリスター（半球状の膨れ）
（ｂ）が生じ、同図（２）のようにロール（ｒ）の圧下
の際に二枚噛み状態となり易く、これは同図（３）に示
すように鋼板表面に山状のスケール疵（ｄ）を生じる原
因となる。この対策として図７のように、ロールの近傍
に高圧水噴射ノズル（３）を設け、噴射流の衝撃作用で
スケールを破砕除去（デスケーリング）するようにして
いる。高圧水噴射流の吹き付けは、鋼材温度の低下を伴
うので、高圧水噴射の実施はできるだけ少ない回数に制
限されている。例えば、正逆パス圧延回数が５回に設定
された粗圧延では、２〜３回のパスチャンスで高圧水噴
射を実施し、また仕上げ圧延工程では、上流側の圧延機
のスタンド間でのみ高圧水噴射を行うようにしている。
粗圧延および仕上げ圧延を経た熱延鋼板は、酸洗処理の
後、冷間圧延され、冷延鋼板は、焼鈍処理（応力除去
等）および表面浄化処理（電解脱脂処理等）を施され
て、電気亜鉛めっきラインに供給される。[0003] Scale is formed on the surface of the steel material in the hot rolling process. In rough rolling, the steel material temperature is high (about 1100 ° C or more),
For this reason, scale generation is remarkable. When the growth stress of the scale exceeds the adhesion stress with the steel sheet surface, the scale (S) is blistered (hemispherical swelling) as shown in FIG.
As shown in FIG. 2B, when the roll (r) is rolled down, two sheets are likely to be in a state of being bitten, which is caused by a mountain-like scale flaw on the steel sheet surface as shown in FIG. d). As a countermeasure, as shown in FIG. 7, a high-pressure water injection nozzle (3) is provided in the vicinity of the roll, and the scale is crushed and removed (descaling) by the impact of the jet flow. Since the spraying of the high-pressure water jet involves a decrease in the temperature of the steel material, the execution of the high-pressure water jet is limited to a minimum number of times. For example, in rough rolling in which the number of times of forward and reverse pass rolling is set to 5, high-pressure water injection is performed with two to three pass chances, and in the finish rolling process, high-pressure water is injected only between stands of the upstream rolling mill. Water injection is performed.
The hot-rolled steel sheet that has undergone rough rolling and finish rolling is cold-rolled after pickling, and the cold-rolled steel sheet is subjected to annealing treatment (stress removal, etc.) and surface purification treatment (electrolytic degreasing treatment, etc.) Supplied to electrogalvanizing line.
【０００４】[0004]
【発明が解決しようとする課題】熱延工程での高圧水噴
射の実施は、冷延鋼板のスケール疵の発生を抑制防止し
表面品質を高めることを可能にする。しかし、健全な表
面を有する冷延鋼板であっても、これをめっき原板とし
て行う電気亜鉛めっきにおいて、めっき表面に松葉状の
模様が現れることがある。めっき表面に現れる松葉状模
様は、めっきの耐食性等に悪影響を及ぼすものではない
が、めっき鋼板の外観を損ない製品価値を低下させる。
この松葉状模様を防止する方法として、めっき条件の制
御、特に初期電析における高電流密度化が有効である
が、それにはめっきラインの鋼板移送速度の制限（通常
のめっき操業に比べて約40％ないしそれ以上の低速度
化）が必要となり、生産性の大幅な低下を免れない。本
発明者等は、電気亜鉛めっき鋼板に現れる松葉状模様の
防止策について鋭意検討の結果、めっき原板として使用
される冷延鋼板の製造工程、特に熱間圧延の粗圧延工程
で実施される高圧水噴射のデスケーリング条件が、めっ
き表面の松葉状模様の発生を左右する重要な因子である
ことを見出した。本発明はこの知見に基づいてなされた
ものである。The implementation of high-pressure water injection in the hot rolling process makes it possible to prevent the occurrence of scale flaws in the cold-rolled steel sheet and to improve the surface quality. However, even in the case of a cold-rolled steel sheet having a healthy surface, a pine needle-shaped pattern may appear on the plating surface in electrogalvanizing using the cold-rolled steel sheet as a plating base sheet. The pine needle-shaped pattern appearing on the plating surface does not adversely affect the corrosion resistance and the like of the plating, but impairs the appearance of the plated steel sheet and lowers the product value.
As a method of preventing this pine needle-shaped pattern, it is effective to control the plating conditions, particularly to increase the current density in the initial electrodeposition, but it is necessary to limit the transfer speed of the steel sheet in the plating line (about 40 times less than in ordinary plating operations). % Or more), and a drastic reduction in productivity is inevitable. The present inventors have conducted intensive studies on measures to prevent crescent-shaped patterns appearing on electrogalvanized steel sheets, and as a result, have found that high-pressure rolling performed in the manufacturing process of a cold-rolled steel sheet used as an original plate for plating, particularly in the rough rolling step of hot rolling. It was found that the descaling condition of the water jet was an important factor in determining the occurrence of the pine needle pattern on the plating surface. The present invention has been made based on this finding.
【０００５】[0005]
【課題を解決するための手段】本発明は、低炭素鋼スラ
ブを、リバース圧延機で正逆パス圧延する粗圧延とタン
デム圧延機で仕上げ圧延する工程からなる熱間圧延に付
し、熱延鋼板を冷間圧延して電気亜鉛めっき用めっき原
板である冷延鋼板を製造する方法において、リバース圧
延機に侵入する鋼材に対しその圧延直前に高圧水噴射流
を吹き付けて鋼材表面のスケールを破砕除去するデスケ
ーリング処理を、リバース圧延の全パスチャンスにおい
て行うことを特徴としている。SUMMARY OF THE INVENTION According to the present invention, a low-carbon steel slab is subjected to hot rolling comprising a step of rough rolling by forward and reverse pass rolling by a reverse rolling mill and a step of finish rolling by a tandem rolling mill. In a method of cold-rolling a steel sheet to produce a cold-rolled steel sheet, which is a base sheet for electrogalvanizing, a high-pressure water jet is applied to the steel material entering the reverse rolling mill immediately before rolling to break the scale on the surface of the steel material It is characterized in that the descaling process to be removed is performed in all pass chances of the reverse rolling.
【０００６】粗圧延における正逆パス圧延の全パスチャ
ンスで高圧水噴射（デスケーリング）を実施する本発明
に対して、選択されたパスチャンス（例えば，５回のパ
ス回数のうち２〜３回）の高圧水噴射を実施している従
来法の場合でも、デスケーリング効果として、本発明の
冷延鋼板と同等の表面品質を有する冷延鋼板を得ること
は可能である。しかし、その冷延鋼板に電気亜鉛めっき
を施すと、前述のように、めっき直前の鋼板表面には存
在しなかった松葉状模様が、めっき後の表面に現れる場
合がある。これと異なり、本発明の冷延鋼板を使用して
行う電気亜鉛めっきでは、上記デスケーリングの効果と
して、そのような松葉状模様の発生はほぼ完全に防止さ
れる。[0006] In contrast to the present invention in which high-pressure water injection (descaling) is performed with all pass chances in forward and reverse pass rolling in rough rolling, a selected pass chance (for example, 2 to 3 out of 5 passes) is used. Even in the case of the conventional method in which high-pressure water injection is carried out, it is possible to obtain a cold-rolled steel sheet having the same surface quality as the cold-rolled steel sheet of the present invention as a descaling effect. However, if the cold-rolled steel sheet is subjected to electrogalvanization, as described above, a pine needle-like pattern that did not exist on the steel sheet surface immediately before plating may appear on the surface after plating. In contrast, in the electrogalvanizing performed using the cold-rolled steel sheet of the present invention, the occurrence of such a pine needle pattern is almost completely prevented as a result of the descaling.
【０００７】図１（１）（２）は、本発明の冷延鋼板を
使用した電気亜鉛めっき鋼板（同図（１））と、従来の
冷延鋼板を使用した電気亜鉛めっき鋼板（同図（２））
のめっき表面品質を示している。冷延鋼板は、すべて健
全な表面品質を有するものを使用している。図の横軸の
「めっき表面品質」の評点は、松葉状模様の発生がなく
健全なめっき表面を「３」とする３段階の評価を示して
いる（供試鋼板の製造条件およびめっき条件の詳細は後
述）。図示のように、従来の冷延鋼板を使用した電気亜
鉛めっき鋼板では、めっき前の鋼板表面に存在しなかっ
た松葉状模様が高い頻度で現れており（同図（２））、
他方本発明の冷延鋼板を使用した電気亜鉛めっき鋼板
は、松葉状模様のない健全なめっき表面品質が確保され
ている（同図（１））。FIGS. 1 (1) and 2 (2) show an electrogalvanized steel sheet using the cold-rolled steel sheet of the present invention (FIG. 1 (1)) and an electrogalvanized steel sheet using a conventional cold-rolled steel sheet (FIG. 1). (2))
5 shows the plating surface quality. All the cold-rolled steel sheets have a sound surface quality. The score of “plating surface quality” on the horizontal axis in the figure indicates a three-level evaluation of a healthy plating surface with no pine needle-shaped pattern as “3” (the production conditions and the plating conditions of the test steel sheet). Details will be described later). As shown in the figure, in the electrogalvanized steel sheet using the conventional cold-rolled steel sheet, a pine needle-like pattern that did not exist on the steel sheet surface before plating appeared at a high frequency ((2) in the same figure),
On the other hand, the electrogalvanized steel sheet using the cold-rolled steel sheet of the present invention has a sound plating surface quality without a crescent-shaped pattern (FIG. 1A).
【０００８】図２（１）（２）は、本発明の冷延鋼板と
従来の冷延鋼板（前記図１の電気亜鉛めっき鋼板をめっ
き原板として使用したもの）について、熱延鋼板の段階
における表面品質を示している（同図（１）: 本発明の
冷延鋼板の熱延鋼板段階，同図（２）: 従来の冷延鋼板
の熱延鋼板段階）。横軸の「熱延鋼板の表面品質」の評
点は、酸洗処理後、冷間圧延前の鋼板表面を肉眼観察
し、山状スケール疵のないものを評点「３」とする３段
階の評価を示している。本発明における熱延鋼板は健全
な表面を有し、従来法における熱延鋼板は、山状スケー
ル疵が高い頻度で発生している。この熱延鋼板の表面品
質のばらつきは前記図１の電気亜鉛めっき鋼板の表面品
質とほぼ対応している。FIGS. 2 (1) and 2 (2) show the cold-rolled steel sheet of the present invention and the conventional cold-rolled steel sheet (using the electrogalvanized steel sheet of FIG. 1 as a plating base sheet) in a hot-rolled steel sheet stage. The surface quality is shown (FIG. (1): hot-rolled steel sheet stage of cold-rolled steel sheet of the present invention, and FIG. 2 (2): hot-rolled steel sheet stage of conventional cold-rolled steel sheet). The rating of the surface quality of the hot-rolled steel sheet on the horizontal axis is a three-level evaluation in which the steel sheet surface after pickling treatment and before cold rolling is visually observed, and those without mountain scale flaws are rated "3". Is shown. The hot-rolled steel sheet according to the present invention has a sound surface, and the hot-rolled steel sheet according to the conventional method has a high frequency of mountain scale flaws. This variation in the surface quality of the hot-rolled steel sheet substantially corresponds to the surface quality of the electrogalvanized steel sheet in FIG.
【０００９】図３は、前記図２および図１より、めっき
原板として使用した冷延鋼板（表面品質はいずれも評点
３）の熱延段階の表面品質と、電気亜鉛めっき鋼板のめ
っき表面品質との関係を示した図である。この図は、熱
延鋼板の表面（酸洗した表面）に山状スケール疵が発生
していると、その熱延鋼板から得られた冷延鋼板の表面
が健全であっても、電気亜鉛めっきを行うと、めっき表
面に松葉状模様を生じ易いことを示している。すなわ
ち、電気亜鉛めっきにおける松葉状模様の発生を確実に
防止し健全なめっき表面品質を保証するためには、めっ
き直前の冷延鋼板が健全な表面品質であることと併せ
て、熱延鋼板の段階における鋼板表面の健全性を必要と
するのである。本発明は、前記のように粗圧延（リバー
ス圧延）における全パスチャンスで高圧水噴射（デスケ
ーリング）を実施することにより、この要件を充足せし
め、製品めっき鋼板の表面品質を確保することを可能に
している。FIG. 3 shows the surface quality of the cold-rolled steel sheet used as the base plate for plating (each having a surface quality of 3) and the surface quality of the electrogalvanized steel sheet from FIG. 2 and FIG. FIG. This figure shows that even if the surface of the hot-rolled steel sheet (pickled surface) has mountain scale flaws, even if the surface of the cold-rolled steel sheet obtained from the hot-rolled steel sheet is sound, it can be electrogalvanized. Shows that a pine needle-shaped pattern is likely to be formed on the plating surface. In other words, in order to reliably prevent the occurrence of pine needle-shaped patterns in electrogalvanizing and to guarantee sound plating surface quality, in addition to the fact that the cold-rolled steel sheet immediately before plating has a sound surface quality, It requires the soundness of the steel sheet surface at the stage. The present invention satisfies this requirement by performing high-pressure water injection (descaling) at all pass chances in the rough rolling (reverse rolling) as described above, thereby making it possible to secure the surface quality of the product plated steel sheet. I have to.
【００１０】[0010]
【発明の実施の形態】本発明のめっき原板である冷延鋼
板は、低炭素鋼を素材として製造される。ここに低炭素
鋼というのは、Ｃ: ０．１％以下，Ｓｉ: ０．４％以
下，Ｍｎ: ０．８％以下，Ｐ: ０．１０％以下，Ｓ:
０．０５０％以下，Ａｌ: ０．１０％以下，残部Ｆｅか
らなる鋼組成，またはこれらの元素と共に、Ｔｉ: ０．
１０％以下，Ｎｂ: ０．１０％以下の１種もしくは２種
を含有する鋼組成を有するものである。具体例として、
いわゆる弱脱酸鋼（C: 0.05%以下, Si: 0.03% 以下, M
n: 0.3 % 以下, P:0.02% 以下, S:0.025%以下, Fe:Ba
l），低炭素Ａｌキルド鋼（C:0.04% 以下,Si:0.04% 以
下, Mn:0.3% 以下, P:0.018%以下, S:0.018%以下, Al:
0.08%以下, Fe:Bal）などが挙げられる。BEST MODE FOR CARRYING OUT THE INVENTION A cold-rolled steel sheet, which is an original plating sheet of the present invention, is manufactured from a low-carbon steel. Here, low-carbon steel is defined as C: 0.1% or less, Si: 0.4% or less, Mn: 0.8% or less, P: 0.10% or less, S:
0.050% or less, Al: 0.10% or less, steel composition consisting of the balance of Fe, or Ti: 0.
It has a steel composition containing one or two of 10% or less and Nb: 0.10% or less. As a specific example,
So-called weakly deoxidized steel (C: 0.05% or less, Si: 0.03% or less, M
n: 0.3% or less, P: 0.02% or less, S: 0.025% or less, Fe: Ba
l), low carbon Al-killed steel (C: 0.04% or less, Si: 0.04% or less, Mn: 0.3% or less, P: 0.018% or less, S: 0.018% or less, Al:
0.08% or less, Fe: Bal).
【００１１】粗圧延工程のリバース圧延における高圧水
噴射のデスケーリング（正逆パス圧延の全パスチャンス
で実施）は、噴射圧力: 約１００kg/cm 2 以上, 噴射水
量:約８００ｌ／min 以上, 鋼材単位表面積当たりの吹
き付け流量: 約５×１０-3m 3 /m2 以上であるのが好ま
しい。噴射圧力の増加によりスケールの破砕除去作用は
強化されるが、ある程度まで増圧すると効果はほぼ飽和
し、それ以上の増圧は鋼材の温度低下の不利を助長する
だけであり、このため噴射圧力は約１６０kg/cm 2 を上
限とするのが適当である。High-pressure water in reverse rolling in the rough rolling process
Injection descaling (all pass opportunities in forward and reverse pass rolling)
Injection pressure: about 100kg / cmTwoOr more, injection water
Amount: About 800l / min or more, blowing per unit surface area of steel
Kicking flow rate: about 5 × 10-3m Three/ mTwoPreferably more than
New Increased injection pressure reduces crushing and removal of scale
The effect is almost saturated when the pressure is increased to some extent
And further boosting contributes to the disadvantage of steel temperature drop
And therefore the injection pressure is about 160kg / cmTwoOn
It is appropriate to set the limit.
【００１２】粗圧延後の仕上げ圧延（タンデム圧延）に
おける高圧水噴射のデスケーリングは、従来のそれと同
様に、タンデム配列の上流側（例えば７台の圧延機が配
列された仕上げ圧延では、上流側の第１〜第３ないし第
４圧延機の間）において実施すればよい。仕上げ圧延工
程の鋼材温度は、粗圧延に比べて低く、スケールの生成
は少ないので、粗圧延で行うような強力な高圧力の噴射
を必要としない。鋼材温度の低下を抑制しつつ所定のデ
スケーリング効果を得る点から、噴射圧力: 約３〜５kg
/cm 2 の範囲が適当である。The descaling of high-pressure water injection in finish rolling (tandem rolling) after rough rolling is performed on the upstream side of the tandem arrangement (for example, on the upstream side in finish rolling in which seven rolling mills are arranged), similarly to the conventional one. Between the first to third and fourth rolling mills). Since the steel material temperature in the finish rolling step is lower than that in the rough rolling and the scale is less generated, it is not necessary to inject a powerful high pressure as in the rough rolling. In order to obtain a predetermined descaling effect while suppressing a decrease in steel temperature, injection pressure: about 3 to 5 kg
The range of / cm 2 is appropriate.
【００１３】鋼材の熱間圧延は、Ａr3点以上（オーステ
ナイト単相温度域）で終了することが必要である。熱延
温度がそれより低くなると、製品鋼板（冷延鋼板）の機
械的性質が損なわれる（特に伸び，絞り等の異方性が強
くなる）からである。このため、仕上げ圧延への導入時
の鋼材温度は、通常約１０１０℃以上（約１０１０〜１
１００℃）に管理される（従来の粗圧延での高圧水噴射
の実施回数を制限しているのは、鋼材温度の低下をでき
るだけ少なくしようとするものである）。本発明の熱間
圧延における鋼材の温度管理の要請は、むろん通常のそ
れと異ならないが、粗圧延の高圧水噴射回数の増加のた
めに、粗圧延終了時点の鋼材温度は従来法と比べて、約
１０℃程度低くなる。この温度低下は、例えば粗圧延と
仕上げ圧延との間の鋼材移送のジョグタイムを短縮する
ことにより補償することもできる。必要ならば、加熱炉
のスラブ抽出温度を高めに設定すればよい。鋼材温度の
高温設定は加熱炉の熱エネルギー消費の増加を必要とす
るが、本発明のめっき表面品質の改善効果は、その不利
を十分に補って余りあるものである。[0013] Hot rolling of the steel material must be completed at the Ar 3 point or higher (austenitic single phase temperature range). If the hot rolling temperature is lower than that, the mechanical properties of the product steel sheet (cold rolled steel sheet) are impaired (especially, anisotropy such as elongation and drawing becomes strong). For this reason, the steel material temperature at the time of introduction into finish rolling is usually about 1010 ° C. or more (about 1010 to 1
(100 ° C.) (the reason why the number of times of performing high-pressure water injection in the conventional rough rolling is limited is to reduce a decrease in steel material temperature as much as possible). The demand for the temperature control of the steel material in the hot rolling of the present invention is, of course, not different from the usual one, but due to the increase in the number of times of high-pressure water injection in the rough rolling, the steel material temperature at the end of the rough rolling is smaller than that of the conventional method. About 10 ° C lower. This temperature drop can also be compensated for, for example, by shortening the jog time of the steel transfer between the rough rolling and the finish rolling. If necessary, the slab extraction temperature of the heating furnace may be set higher. Although setting the steel material at a high temperature requires an increase in the heat energy consumption of the heating furnace, the effect of improving the plating surface quality of the present invention is more than enough to compensate for the disadvantage.
【００１４】上記粗圧延と仕上げ圧延からなる熱間圧延
の後の工程、すなわち熱延鋼板の酸洗，冷間圧延，冷延
鋼板の焼鈍および表面浄化処理等は、常法に従って行わ
れる。電気亜鉛めっき操業も、特別の制限や条件を必要
とせず、常法に従って行えばよい。The steps after the hot rolling including the rough rolling and the finish rolling, that is, the pickling of the hot-rolled steel sheet, the cold rolling, the annealing of the cold-rolled steel sheet, the surface cleaning treatment, and the like are performed according to a conventional method. The electrogalvanizing operation does not require any special restrictions or conditions, and may be performed according to a conventional method.
【００１５】[0015]
【実施例】図５の熱延装置において、粗圧延および仕上
げ圧延を行って熱延鋼板を得、酸洗処理の後、冷間圧延
する。冷延鋼板に焼鈍処理，表面浄化処理を施し、連続
電気亜鉛めっきを行う。 〔１〕鋼材種および組成(wt%) 弱脱酸鋼（Ａ）および低炭素Ａｌキルド鋼（Ｂ）。 Ａ: C 0.043, Si 0.005, Mn 0.19, P 0.020, S 0.013,
Al 0.016, Fe Bal Ｂ: C 0.020, Si 0.020, Mn 0.18, P 0.013, S 0.015,
Al 0.040, Fe Bal 〔２〕スラブ加熱温度（加熱炉抽出温度）: 1100〜1230
℃EXAMPLE In the hot rolling apparatus of FIG. 5, rough rolling and finish rolling are performed to obtain a hot rolled steel sheet, and after cold pickling, cold rolling. The cold-rolled steel sheet is subjected to annealing treatment and surface purification treatment, and is subjected to continuous electrogalvanizing. [1] Steel type and composition (wt%) Weakly deoxidized steel (A) and low-carbon Al-killed steel (B). A: C 0.043, Si 0.005, Mn 0.19, P 0.020, S 0.013,
Al 0.016, Fe Bal B: C 0.020, Si 0.020, Mn 0.18, P 0.013, S 0.015,
Al 0.040, Fe Bal [2] Slab heating temperature (heating furnace extraction temperature): 1100-1230
° C
【００１６】〔３〕熱間圧延 (1)粗圧延 正逆パス圧延（パス回数５回）で減厚しシートバー（厚
さ30〜55mm) とする。 ・高圧水噴射（デスケーリング）: 圧延機R1に付設した
ノズル（３）により、正逆パス圧延の各パスチャンスご
とに実施（図４の♯1 〜♯5 ）。噴射圧 160kg/cm 2 ,
噴射水量 860l/min, 吹き付け流量 5.3ｘ10-3m 3 /m
2 ( 鋼材単位面積当たり） ・粗圧延出側の鋼材温度: 1020〜1100℃[3] Hot rolling (1) Rough rolling The thickness is reduced by forward and reverse pass rolling (5 passes) to form a sheet bar (thickness: 30 to 55 mm). -High pressure water injection (descaling): The nozzle (3) attached to the rolling mill R1 is used for each pass chance of forward and reverse pass rolling (# 1 to # 5 in Fig. 4). Injection pressure 160kg / cm 2 ,
Injection water amount 860l / min, spray flow 5.3x10 -3 m 3 / m
2 (per unit area of steel material) ・ Steel material temperature at the exit side of rough rolling: 1020 to 1100 ℃
【００１７】(2) 仕上げ圧延（タンデム圧延） ７基のタンデム圧延機による１パス圧延により、熱延鋼
板（板厚2.0 〜4.2mm）を得る。なお、粗圧延における
デスケーリング（高圧水噴射）の強化のため、粗圧延の
出側の鋼材温度（1020〜1100℃) は、従来法での粗圧延
出側の鋼材温度より約１０℃低いが、スラブの加熱炉抽
出温度は従来のままとし、粗圧延から仕上げ圧延までの
ジョグタイムを短縮することにより、仕上げ圧延入側の
鋼材温度を従来レベルに維持した。 ・仕上げ圧延入側の鋼材温度: 1010〜1100℃ ・高圧水噴射（デスケーリング） 第１〜第５圧延機(F1-F5）の各スタンド間で実施。 噴射圧 3 kg/cm 2 ・仕上げ圧延終了温度: 870 ℃以上(2) Finish Rolling (Tandem Rolling) A hot-rolled steel sheet (sheet thickness 2.0 to 4.2 mm) is obtained by one-pass rolling using seven tandem rolling mills. In order to strengthen descaling (high-pressure water injection) in rough rolling, the steel material temperature (1020 to 1100 ° C) on the outlet side of rough rolling is about 10 ° C lower than the steel material temperature on the rough rolling outlet side in the conventional method. The steel temperature on the entry side of the finish rolling was maintained at the conventional level by shortening the jog time from rough rolling to finish rolling while keeping the slab heating furnace extraction temperature unchanged.・ Steel material temperature on the entry side of finish rolling: 1010-1100 ℃ ・ High-pressure water injection (descaling) Implemented between the stands of the first to fifth rolling mills (F1-F5). Injection pressure 3 kg / cm 2・ Finishing finish temperature: 870 ℃ or more
【００１８】〔３〕冷間圧延および焼鈍処理 (1) 冷間圧延: 圧下率40〜80％，冷延板厚さ 0.8〜1.6
mm。 (2) 焼鈍処理: 温度 700℃，炉内均熱時間 60 秒[3] Cold rolling and annealing treatment (1) Cold rolling: reduction ratio 40-80%, cold-rolled sheet thickness 0.8-1.6
mm. (2) Annealing treatment: temperature 700 ℃, soaking time in furnace 60 seconds
【００１９】〔４〕連続電気亜鉛めっき 焼鈍処理した冷延鋼板をめっきラインに導入し、表面浄
化処理（防錆油等の除去）の後、めっき浴槽に導入す
る。 (1)浄化処理 アルカリ電解脱脂（アルカリ溶液: 30±0.5mass ％ホメ
ザリン水溶液, 液温:60±5 ℃，電流密度: 10A/dm
2 )。電解脱脂後、表面を酸液（硫酸水溶液）で中和
し、ついで水洗する。 (2)めっき条件 めっき浴通電セル数: ６セル 通板ライン速度: 70 m/min 電流密度: 120 Ａ/dm 2 めっき付着量: 20〜40 g/ m 2 （片面当り）[4] Continuous electrogalvanizing A cold-rolled steel sheet subjected to annealing treatment is introduced into a plating line, and after surface purification treatment (removal of rust-preventive oil and the like), introduced into a plating bath. (1) Purification treatment Alkaline electrolytic degreasing (alkaline solution: 30 ± 0.5mass% fomezarin aqueous solution, liquid temperature: 60 ± 5 ℃, current density: 10A / dm
2 ). After electrolytic degreasing, the surface is neutralized with an acid solution (sulfuric acid aqueous solution) and then washed with water. (2) Plating conditions Number of cells in plating bath: 6 cells Passing line speed: 70 m / min Current density: 120 A / dm 2 Coating weight: 20-40 g / m 2 (per side)
【００２０】[0020]
【比較例】粗圧延（正逆パス圧延回数５回）における高
圧水噴射（デスケーリング）を、第１パス圧延の直前，
第３パスの直前，および第４パスの直前（図４中，♯
１，♯３および♯４）において計３回実施する。粗圧延
工程の高圧水噴射（デスケーリング）を上記３回実施す
る点を除いて、実施例と実質的に同じ工程および処理条
件により、めっき原板を得、電気亜鉛めっきを行う。[Comparative Example] High-pressure water injection (descaling) in rough rolling (5 forward and reverse pass rolling times) was performed immediately before the first pass rolling.
Immediately before the third pass and immediately before the fourth pass (in FIG. 4, ♯
Perform a total of 3 times in 1, 3, and 4). Except that the high-pressure water injection (descaling) in the rough rolling step is performed three times as described above, an original galvanized sheet is obtained and electrogalvanized by the substantially same steps and processing conditions as those of the example.
【００２１】図１（１）（２）は、発明例および比較例
の冷延鋼板をめっき原板として製造した電気亜鉛めっき
鋼板のめっき表面品質を、下記の評価基準（肉眼観察）
により評価したものである〔図（１）: 実施例の冷延鋼
板使用，図（２）: 比較例の冷延鋼板使用〕。 （めっき表面の松葉状模様発生状況） 評点３: 発生皆無，評点２: 中程度の発生，評点１: 発
生顕著FIGS. 1 (1) and (2) show the following evaluation criteria (visual observation) of the plating surface quality of electrogalvanized steel sheets manufactured using the cold-rolled steel sheets of the invention examples and comparative examples as plating base sheets.
[Figure (1): Use of cold-rolled steel sheet of Example, Figure (2): Use of cold-rolled steel sheet of Comparative Example]. (Situation of occurrence of pine needle-shaped pattern on plating surface) Rating 3: No occurrence, Rating 2: Moderate occurrence, Rating 1: Remarkable occurrence
【００２２】図２は、発明例および比較例における熱延
鋼板の表面品質（酸洗表面品質）を、下記の評価基準に
基づいて評価した図である〔図（１）: 発明例における
熱延鋼板，図（２）: 比較例における熱延鋼板〕。 （熱延鋼板の山状スケール疵発生状況） 評点３: 発生皆無，評点２: 中程度の発生，評点１: 発
生顕著FIG. 2 is a diagram in which the surface quality (pickling surface quality) of the hot-rolled steel sheet in the invention example and the comparative example was evaluated based on the following evaluation criteria [FIG. Steel sheet, Fig. (2): Hot rolled steel sheet in comparative example]. (Situation of mountain scale flaw occurrence of hot-rolled steel sheet) Rating 3: No occurrence, Rating 2: Moderate occurrence, Rating 1: Remarkable occurrence
【００２３】図３は上記電気亜鉛めっき鋼板と熱延鋼板
の表面品質との関係を示している（図中、○: 鋼材Ａ，
□: 鋼材Ｂ）。図１〜図３から明らかなように、従来法
による冷延鋼板を使用する場合と比較して、本発明の冷
延鋼板を使用した電気亜鉛めっき鋼板は、松葉状模様の
ない健全なめっき表面品質が確保されており、両者の差
異は歴然である。FIG. 3 shows the relationship between the electrogalvanized steel sheet and the surface quality of the hot-rolled steel sheet (in the figure, ○: steel material A,
□: Steel material B). As is clear from FIGS. 1 to 3, the galvanized steel sheet using the cold-rolled steel sheet of the present invention has a sounder plating surface without a crescent-shaped pattern as compared with the case of using the cold-rolled steel sheet according to the conventional method. The quality is assured, and the difference between the two is obvious.
【００２４】[0024]
【発明の効果】本発明により製造されるめっき原板であ
る冷延鋼板は、電気亜鉛めっきにおいて、めっき表面の
松葉状模様の発生を確実に防止し、めっき表面品質を向
上安定化することができ、電気亜鉛めっきの電析条件を
制御して松葉状模様を防止する場合のような制約（めっ
きライン速度の大幅な低減）を受けず、効率よく電気亜
鉛めっき操業を遂行し、改良されためっき品質を確保す
ることを可能にするものである。According to the present invention, the cold-rolled steel sheet, which is the original plate for plating, can reliably prevent the generation of pine needle-like patterns on the plating surface in electrogalvanizing, and can improve and stabilize the quality of the plating surface. Efficient electrogalvanizing operation and improved plating without the restrictions (significant reduction in plating line speed) like controlling the electrodeposition conditions of electrogalvanizing to prevent crutches It is possible to ensure quality.
【図１】電気亜鉛めっき鋼板の表面品質の分布を示すグ
ラフである〔図（１）: 発明例の冷延鋼板を使用，図
（２）従来の冷延鋼板を使用〕。FIG. 1 is a graph showing the distribution of the surface quality of an electrogalvanized steel sheet [FIG. (1): using a cold-rolled steel sheet of the invention example, FIG. 2 (using a conventional cold-rolled steel sheet)].
【図２】熱延段階における鋼板表面（熱延鋼板の酸洗表
面）の品質の分布を示すグラフである〔図（１）: 本発
明における熱延鋼板，図（２）: 従来の熱延鋼板〕。FIG. 2 is a graph showing the distribution of the quality of the steel sheet surface (the pickled surface of the hot-rolled steel sheet) in the hot-rolling stage [FIG. (1): Hot-rolled steel sheet in the present invention, FIG. steel sheet〕.
【図３】電気亜鉛めっき鋼板のめっき表面品質と、めっ
き原板の熱間圧延段階の鋼板表面（熱延鋼板の酸洗表
面）の品質との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the plating surface quality of an electrogalvanized steel sheet and the quality of a steel sheet surface (a pickling surface of a hot-rolled steel sheet) in a hot rolling stage of an original plating sheet.
【図４】粗圧延での正逆パス圧延における高圧水噴射の
実施の説明図である。FIG. 4 is an explanatory diagram of the implementation of high-pressure water injection in forward and reverse pass rolling in rough rolling.
【図５】粗圧延（リバース圧延）と仕上げ圧延（タンデ
ム圧延）とからなる熱間圧延工程を示す図である。FIG. 5 is a view showing a hot rolling process including rough rolling (reverse rolling) and finish rolling (tandem rolling).
【図６】熱延鋼板表面のブリスターおよびスケール疵の
発生機構を示す図である。FIG. 6 is a view showing a mechanism of generation of blisters and scale flaws on the surface of a hot-rolled steel sheet.
【図７】高圧水噴射ノズルによるデスケーリング処理を
示す図である。FIG. 7 is a diagram showing a descaling process by a high-pressure water injection nozzle.
１: 粗圧延装置 R1: リバース圧延機 ２: 仕上げ圧延装置 F1〜F7: 圧延機 ３: デスケーリング用高圧水噴射ノズル Ｓ: スケール ｒ: ロール Ｐ: 鋼板 ｂ: ブリスター（スケールの半球状膨れ） ｄ: 山状スケール疵 1: Rough rolling mill R1: Reverse rolling mill 2: Finish rolling mill F1-F7: Rolling mill 3: High pressure water injection nozzle for descaling S: Scale r: Roll P: Steel plate b: Blister (semispherical swelling of scale) d : Mountain scale flaw
フロントページの続き (72)発明者 有働 信太郎 大阪府堺市石津西町５番地 日新製鋼株式 会社堺製造所内 (72)発明者 津井 祐司 大阪府堺市石津西町５番地 日新製鋼株式 会社堺製造所内Continuing from the front page (72) Inventor Shintaro 5 Ishizu Nishimachi, Sakai City, Osaka, Nisshin Steel Co., Ltd.Sakai Works (72) Inventor Yuji 5 Ishizu Nishimachi, Sakai City, Osaka Nisshin Steel Co., Ltd.Sakai Factory
Claims (1)
逆パス圧延する粗圧延とタンデム圧延機で仕上げ圧延す
る工程からなる熱間圧延に付し、熱延鋼板を冷間圧延し
て電気亜鉛めっき用めっき原板である冷延鋼板を製造す
る方法において、リバース圧延機に侵入する鋼材に対し
その圧延直前に高圧水噴射流を吹き付けて鋼材表面のス
ケールを破砕除去するデスケーリング処理を、リバース
圧延の全パスチャンスにおいて行うことを特徴とする電
気亜鉛めっき用めっき原板の製造方法。1. A low-carbon steel slab is subjected to hot rolling including a step of rough rolling in which a reverse rolling mill performs forward and reverse pass rolling and a step of finishing rolling in a tandem rolling mill, and a hot-rolled steel sheet is cold-rolled. In a method of manufacturing a cold-rolled steel sheet which is a galvanized base sheet, a descaling process of crushing and removing scale on a steel material surface by spraying a high-pressure water jet immediately before rolling on a steel material entering a reverse rolling mill is performed by a reverse process. A method for producing an electrogalvanized original plate, which is performed in all pass chances of rolling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20368997A JPH1147806A (en) | 1997-07-30 | 1997-07-30 | Manufacture of black plate for electrogalvanizing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20368997A JPH1147806A (en) | 1997-07-30 | 1997-07-30 | Manufacture of black plate for electrogalvanizing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH1147806A true JPH1147806A (en) | 1999-02-23 |
Family
ID=16478221
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20368997A Withdrawn JPH1147806A (en) | 1997-07-30 | 1997-07-30 | Manufacture of black plate for electrogalvanizing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH1147806A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006181612A (en) * | 2004-12-28 | 2006-07-13 | Jfe Steel Kk | Method for producing pickled steel sheet having excellent surface property |
| CN103506382A (en) * | 2013-07-31 | 2014-01-15 | 秦皇岛首秦金属材料有限公司 | Production method for improving surface quality of thick-standard ship plate |
| CN112210738A (en) * | 2020-11-20 | 2021-01-12 | 山东富海材料科技有限公司 | Parallel multi-point continuous hot-dip galvanizing unit for high-hardness ultrathin strip steel |
-
1997
- 1997-07-30 JP JP20368997A patent/JPH1147806A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006181612A (en) * | 2004-12-28 | 2006-07-13 | Jfe Steel Kk | Method for producing pickled steel sheet having excellent surface property |
| CN103506382A (en) * | 2013-07-31 | 2014-01-15 | 秦皇岛首秦金属材料有限公司 | Production method for improving surface quality of thick-standard ship plate |
| CN112210738A (en) * | 2020-11-20 | 2021-01-12 | 山东富海材料科技有限公司 | Parallel multi-point continuous hot-dip galvanizing unit for high-hardness ultrathin strip steel |
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| A300 | Withdrawal of application because of no request for examination |
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