JP4523878B2 - Method and apparatus for producing surface-treated steel sheet with excellent appearance - Google Patents

Method and apparatus for producing surface-treated steel sheet with excellent appearance Download PDF

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JP4523878B2
JP4523878B2 JP2005179904A JP2005179904A JP4523878B2 JP 4523878 B2 JP4523878 B2 JP 4523878B2 JP 2005179904 A JP2005179904 A JP 2005179904A JP 2005179904 A JP2005179904 A JP 2005179904A JP 4523878 B2 JP4523878 B2 JP 4523878B2
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steel sheet
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誠司 杉山
充徳 桧枝
耕志 井本
貢 梶原
晶弘 神野
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Nippon Steel Corp
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Description

この発明は、表面処理鋼板の製造方法およびその装置、特に外観ならびに製品歩留まりに優れた電気めっき鋼板または化成処理鋼板の製造方法およびその装置に関する。
さらには、均質かつ美麗な外観品質の前提となる表面処理前の鋼板の表面清浄性を、容易かつ正確に評価することができる鋼板表面の清浄性確認装置に関する。
The present invention relates to a method and apparatus for manufacturing a surface-treated steel sheet, and more particularly to a method and apparatus for manufacturing an electroplated steel sheet or chemical conversion-treated steel sheet having excellent appearance and product yield.
Furthermore, the present invention relates to an apparatus for confirming the cleanliness of a steel sheet surface, which can easily and accurately evaluate the surface cleanliness of the steel sheet before the surface treatment, which is a prerequisite for a homogeneous and beautiful appearance quality.

近年における表面処理鋼板には、防錆性に加えて、プレス成形性や溶接性、塗装性など様々な性能が求められている。しかし、光沢度や色調にむらのない均質かつ美麗な外観品質が求められることは現在も変わるところはなく、ユーザからの要求は以前にも増して厳しいものとなっている。   In recent years, surface treated steel sheets are required to have various performances such as press formability, weldability, and paintability in addition to rust prevention. However, the demand for uniform and beautiful appearance quality without uneven glossiness and color tone has not changed, and the demands from users have become more severe than ever.

一般に、表面処理鋼板の外観品質は、焼鈍処理された冷延鋼板(原板)の表面状態が大きく影響する。このため、表面処理設備の前段設備である連続焼鈍ラインの前処理工程においては、アルカリ洗浄処理、リンス洗浄処理、および液切り処理を施すことにより、均質かつ美麗な外観品質の前提となる鋼板の表面清浄性を確保している。また、必要に応じて、アルカリ洗浄処理とリンス洗浄処理の間で、鋼板表面に存在する酸化膜(スケール)を除去する酸洗処理が施される場合もある。
ここで、アルカリ洗浄処理とは、焼鈍前の冷延鋼板の表面から防錆油や調質圧延油等の油脂分を除去する処理をいい、一般には冷延鋼板を脱脂処理槽に浸漬して洗浄される。また、リンス洗浄処理とは、アルカリ洗浄した冷延鋼板の表面からアルカリ洗浄処理で使用した洗浄液を除去する処理をいい、通常アルカリ洗浄した冷延鋼板を洗浄槽(リンス槽)に浸漬して洗浄されるが、スプレー洗浄される場合もある。さらに、液切り処理とは、リンス洗浄した冷延鋼板の表面からリンス洗浄処理で使用したリンス洗浄液を除去する処理をいい、例えば、リンス洗浄した冷延鋼板を一対のリンガーロールの間に挟みこんで、鋼板表面に付着したリンス洗浄液を搾り取っている。
In general, the appearance quality of a surface-treated steel sheet is greatly influenced by the surface state of the annealed cold-rolled steel sheet (original sheet). For this reason, in the pre-treatment process of the continuous annealing line, which is the pre-stage equipment of the surface treatment equipment, by performing alkali cleaning treatment, rinsing cleaning treatment, and liquid drainage treatment, the steel plate that is a prerequisite for homogeneous and beautiful appearance quality Ensures surface cleanliness. Moreover, the pickling process which removes the oxide film (scale) which exists in the steel plate surface may be performed between an alkali cleaning process and a rinse cleaning process as needed.
Here, the alkali cleaning treatment refers to a treatment for removing fats and oils such as rust preventive oil and temper rolling oil from the surface of the cold rolled steel sheet before annealing, and generally the cold rolled steel sheet is immersed in a degreasing treatment tank. Washed. The rinse cleaning treatment is a treatment for removing the cleaning liquid used in the alkali cleaning treatment from the surface of the alkali-washed cold-rolled steel plate. Usually, the alkali-washed cold-rolled steel plate is immersed in a cleaning bath (rinsing bath) for cleaning. However, it may be spray cleaned. Furthermore, the liquid draining process refers to a process of removing the rinse cleaning liquid used in the rinse cleaning process from the surface of the rinse-cleaned cold rolled steel sheet. For example, the rinsed cold rolled steel sheet is sandwiched between a pair of ringer rolls. The rinse cleaning liquid adhering to the steel plate surface is squeezed out.

しかし、溶融めっき等のように鋼板表面に被覆される皮膜が厚い場合には、このような前処理を行うことにより鋼板表面の清浄性を十分に確保できるが、電気めっきや化成処理の場合には、鋼板表面に被覆される皮膜が非常に薄いことから、その外観品質は原板の表面状態の影響を特に敏感に受けやすく、他の表面処理と比較して外観不良が生じやすい。   However, when the coating on the steel sheet surface is thick, such as hot dipping, it is possible to sufficiently ensure the cleanliness of the steel sheet surface by performing such pretreatment, but in the case of electroplating or chemical conversion treatment. Since the film coated on the surface of the steel plate is very thin, the appearance quality is particularly sensitive to the influence of the surface state of the original plate, and appearance defects are likely to occur compared to other surface treatments.

その1つの形態として、リンス洗浄液の僅かな汚染や不十分な液切りが原因となって、表面処理した鋼板の表面に筋状ないし帯状の模様(以下、液残り模様と称する。)が発現する外観不良が知られている(例えば、特許文献1参照)。当該液残り模様を図1(a)に示すが、これは、アルカリ洗浄または酸洗処理した鋼板を浸漬洗浄するリンス洗浄液が汚れていたり、このリンス洗浄液の液切りが不十分であると、リンス洗浄液に含まれる特定の成分が鋼板表面に付着することになり、この状態で焼鈍を行うと、水分が蒸発するとともに付着した特定成分が鋼板表面上に不均一に焼き付き、さらに酸洗、電気めっき等の表面処理を行うと、特定の成分が焼き付いた部位とそうでない部位とでめっき等の付着むらが生じて、これが筋状ないし帯状の模様、すなわち液残り模様となって現れ、鋼板の外観品質を大きく損なう現象である。適正な洗浄が行なわれた場合には、図1(b)に示すとおり、液残り模様は発現しない。   As one form thereof, a streak-like or band-like pattern (hereinafter referred to as a liquid remaining pattern) appears on the surface of the surface-treated steel sheet due to slight contamination of the rinse cleaning liquid or insufficient drainage. Appearance defects are known (see, for example, Patent Document 1). The liquid remaining pattern is shown in FIG. 1 (a). This is because the rinse cleaning solution for immersing and washing the steel plate that has been subjected to alkali cleaning or pickling treatment is contaminated or if the rinse cleaning solution is insufficiently drained. Specific components contained in the cleaning solution will adhere to the surface of the steel sheet, and if annealing is performed in this state, the water will evaporate and the specific components that adhere will seize unevenly on the surface of the steel sheet. When surface treatment such as the above is performed, uneven adhesion of plating, etc. occurs in the part where the specific component is baked in and the part where it is not, and this appears as a streak-like or strip-like pattern, that is, a liquid residue pattern, and the appearance of the steel sheet This is a phenomenon that greatly impairs quality. When proper cleaning is performed, the liquid residue pattern does not appear as shown in FIG.

この液残り模様における第一の特徴は、前記した特定成分が焼鈍後の鋼板表面に焼き付いているか否かを、目視によっては容易に判別できないことである。このため、特定成分が焼鈍後の鋼板表面に焼き付いているにも拘わらず、後工程である酸洗・電気めっきライン等を通板させてしまうため、当該処理後に液残り模様が発現し、表面処理に要した作業自体が無駄となり、製品歩留まりが低下した。また、液残り模様が発現して初めて前処理工程における洗浄不良等に気付くため、原板のみならず焼鈍に要した作業自体までもが無駄となり、製品歩留まりが低下したのである。
そしてこの第二の特徴は、いったん焼鈍によって前記特定成分が鋼板表面に焼き付いてしまうと、容易には除去できないことである。たとえ酸洗によって除去できたとしても、特定成分が焼き付かなった部位は過酸洗になって表面が荒れた状態となるから、特定成分が焼き付いてこれを除去した部位と焼き付かなかった部位とでめっき等の付着むらが生じ、結局は液残り模様が発現してしまうのである。
The first feature of the liquid residue pattern is that it cannot be easily discriminated by visual observation whether or not the above-mentioned specific component is seized on the surface of the steel sheet after annealing. For this reason, in spite of the specific component being baked on the surface of the steel sheet after annealing, a pickling / electroplating line, etc., which is a subsequent process, is passed through, so that a liquid residue pattern appears after the treatment, and the surface The work itself required for processing was wasted and the product yield was reduced. In addition, since a defective liquid pattern is not noticed until the liquid remaining pattern is developed, not only the original plate but also the work itself required for annealing is wasted, resulting in a decrease in product yield.
And this 2nd characteristic is that once the said specific component is seized on the steel plate surface by annealing, it cannot be easily removed. Even if it can be removed by pickling, the part where the specific component is burned out becomes a state where the surface is roughened due to peracid washing, and the part where the specific component is burned out and removed and the part that is not burned out As a result, uneven adhesion such as plating occurs, and eventually a liquid residue pattern appears.

なお、鋼板に液残り模様が発現するメカニズムについては、現在のところはっきりと解明されていないが、本発明者は独自の調査研究によって、以下のとおり推定している。
液残り模様が発現する条件は、(1)一定量の硫酸イオンが鋼板上に付着・乾燥すること、(2)この鋼板を加熱処理すること、(3)最後に酸洗すること、の3つであり、条件が一つでも欠けると発現しないことを実験で確認している。従って液残り模様のメカニズムは、硫酸イオン濃度の高いリンス洗浄水が鋼板に付着した後、鋼板が焼鈍炉内で加熱される際に鋼板表面にFe−S系の複合酸化物が生成され、焼き付いた状態となる。この複合酸化物は、直接肉眼で確認できないものの、酸で除去されにくい物質であるため、鋼板表面にこれが生成された部分とされていない部分では、酸洗処理時にムラが生じ、模様が発現していると推定している。
以上述べたことから明らかなとおり、当該液残り模様の発生とこれによる製品歩留まりの低下を防ぐためには、いかに焼鈍前の鋼板の表面清浄性を確保出来るかにかかっていた。
In addition, although the mechanism by which a liquid residue pattern appears on a steel plate has not been clearly elucidated at present, the present inventor presumes as follows by original research.
The conditions under which the liquid residue pattern appears are as follows: (1) a certain amount of sulfate ions adhere to and dry on the steel sheet, (2) heat-treat the steel sheet, and (3) finally pickle. It has been confirmed by experiments that even if one condition is missing, it does not appear. Therefore, the mechanism of the remaining pattern is that after the rinse water with high sulfate ion concentration adheres to the steel sheet, when the steel sheet is heated in the annealing furnace, Fe-S based complex oxide is generated on the surface of the steel sheet and seizes. It becomes the state. This composite oxide is a substance that cannot be confirmed directly with the naked eye, but is difficult to remove with an acid. Therefore, unevenness occurs in the pickling process on the surface of the steel sheet where it is not generated, and a pattern appears. It is estimated that
As apparent from the above description, in order to prevent the occurrence of the liquid residue pattern and the decrease in product yield due to this, it depends on how the surface cleanliness of the steel sheet before annealing can be ensured.

そうすると、液残り模様の発現要因の一つはリンス洗浄液に含まれる有害成分、特に硫酸イオンであるから、当該発現要因自体を解消して当該問題を抜本的に解決しようとするのが極めて自然な考え方である。
その一つがリンス洗浄液に純水を使用する方法である。純水は有害な硫酸イオンの濃度が極めて低く、また、液切りが不十分であっても鋼板表面に付着する硫酸イオンは微量となることから、純水の使用によって当該問題を完全に解決できるはずである。
しかしながら、リンス洗浄処理工程においては大量のリンス洗浄液を必要とし、しかも純水は高価であることからコスト的に見合わず、実際には製造現場で大量に使用できないのである。
In that case, one of the causes of the residual liquid pattern is a harmful component contained in the rinse solution, particularly sulfate ions, so it is very natural to try to solve the problem drastically by eliminating the expression factor itself. It is a way of thinking.
One of them is a method of using pure water as a rinse cleaning solution. Pure water has a very low concentration of harmful sulfate ions, and even if the drainage is insufficient, the amount of sulfate ions adhering to the steel sheet surface is very small, so the use of pure water can completely solve the problem. It should be.
However, a large amount of rinse cleaning liquid is required in the rinse cleaning process, and pure water is expensive, so it is not cost-effective and cannot be used in large quantities at the manufacturing site.

このため、多くの製造現場では、従来からコスト的に有利な工業用水を使用することによって対応してきたし、現在もなお当該方法で対応している。
しかし、工業用水は、基本的には貯水池や河川から引いてくる水であるため、その水質は、気象条件等の外的環境によって大きく変動する。例えば、梅雨の時期には工業用水中の硫酸イオン濃度は低いが、晴れの日が続く夏場になると硫酸イオン濃度が上昇してしまうのである。
したがって、工業用水を大量に使用してリンス洗浄液の汚染を防止する方法は、硫酸イオン濃度が低く、かつ、液切りも適正に実施されれば一定の効果を発揮できるが、気象条件等の外的環境によって水質が大きく変動するので、使用水量の決定にあっては熟練作業者の経験やノウハウに頼らざるを得ない実情があった。また、コスト的に有利な工業用水とはいっても使用水量は極力抑えたいところ、上記の通りであるから、製品品質を重視するあまり過剰な洗浄をすることも珍しくなく、必ずしもコスト的に有利な方法とは言えない側面があった。
さらに工業用水を使用する上での最大の課題は、工業用水には有害成分の一つである硫酸イオンが含まれているため、純水を使用する場合と異なり、たとえ大量に使用したとしても液残り模様の発現を防げない場合があるということである。
For this reason, many manufacturing sites have conventionally responded by using industrial water which is advantageous in terms of cost, and still respond by this method.
However, since industrial water is basically water drawn from reservoirs and rivers, the water quality varies greatly depending on the external environment such as weather conditions. For example, although the sulfate ion concentration in industrial water is low during the rainy season, the sulfate ion concentration increases in the summer when the sunny day continues.
Therefore, the method of using a large amount of industrial water to prevent contamination of the rinsing cleaning liquid can exert a certain effect if the sulfate ion concentration is low and the liquid draining is properly performed. Since the water quality fluctuates greatly depending on the actual environment, there was a fact that it was necessary to rely on the experience and know-how of skilled workers in determining the amount of water used. In addition, although it is industrial water that is cost-effective, the amount of water to be used is to be suppressed as much as possible. As described above, it is not uncommon to perform excessive cleaning with an emphasis on product quality. There was an aspect that could not be said to be a method.
In addition, the biggest problem in using industrial water is that industrial water contains sulfate ions, which are one of the harmful components, so unlike pure water, even if used in large quantities. In other words, the appearance of the liquid residue pattern may not be prevented.

さらには、たとえ硫酸イオン濃度が低かったとしても、その後に行われる液切りが不十分であると液残り模様が発現するという問題もある。すなわち、例えば特許文献1においては、鋼板表面に付着した洗浄液をリンガーロールで液切りを行い、次に水蒸気を鋼板表面に吹き付けて洗浄し、さらに後段に配置されたリンガーロールで再び液切りを行う方法が開示されているが、リンガーロールは一般的にゴム製であるため、鋼板の鋭利な端部で筋状のキズが付きやすく、キズの程度が進行(悪化)すると、液残り模様の発現要因の一つとなってしまうのである。
具体的には、一対のロールを鋼板表面に圧着させて鋼板表面に付着したリンス洗浄液を搾り取るリンガーロールにキズが生じると、当該キズが生じた部分にはリンス洗浄液が集中し、リンガーロールを通過した鋼板表面にはリンス洗浄液が筋状ないし帯状となって残留する。したがって、この状態で焼鈍を行うと水分が蒸発するとともに付着した有害成分が鋼板表面上に筋状ないし帯状となって焼き付き、この上に電気めっき等の表面処理を行うと、これが筋状ないし帯状の模様、すなわち液残り模様となって現れ、鋼板の外観品質を大きく損なうことになるのである。これが、たとえリンス洗浄液に含まれる硫酸イオン濃度が低かったとしても、リンガーロールの損傷等により液切りが不十分になると液残り模様が発現するメカニズムである。
Furthermore, even if the sulfate ion concentration is low, there is a problem that a liquid residue pattern appears if the subsequent draining is insufficient. That is, for example, in Patent Document 1, the cleaning liquid adhering to the steel sheet surface is drained with a ringer roll, then water vapor is sprayed onto the steel sheet surface for cleaning, and further draining is performed with a ringer roll disposed at a later stage. Although the method is disclosed, since the ringer roll is generally made of rubber, it is easy to get a streak-like scratch at the sharp edge of the steel sheet, and when the degree of the scratch progresses (deteriorates), the appearance of the liquid residue pattern It becomes one of the factors.
Specifically, when scratches occur in the ringer roll that presses the rinse cleaning liquid adhered to the steel sheet surface by pressing the pair of rolls onto the steel sheet surface, the rinse cleaning liquid concentrates on the scratched portion and passes through the ringer roll. The rinse cleaning liquid remains in the form of streaks or strips on the surface of the steel sheet. Therefore, when annealing is performed in this state, moisture is evaporated and the adhering harmful components are streaked or banded on the surface of the steel sheet, and when surface treatment such as electroplating is performed on the surface, this is striped or banded. That is, it appears as a liquid residue pattern, which greatly deteriorates the appearance quality of the steel sheet. This is a mechanism that even if the concentration of sulfate ions contained in the rinsing cleaning liquid is low, a residual liquid pattern appears when the liquid drainage becomes insufficient due to damage of the ringer roll or the like.

そこで、別のアプローチの仕方として、鋼板表面に付着した有害成分の付着量を成分分析装置によって測定し、付着量が規定値以下であることを確認(管理)してから、焼鈍および表面処理を施す方法が開示されている(例えば、特許文献1参照)。
しかしながら、化学分析装置やX線分光分析装置等によって得られるデータは、鋼板表面上のある1点、すなわち計測点におけるポイント的なデータでしかないため、前記付着物の分布や形態を正確に把握できない。このため、たとえ付着量が規定値以下であっても、表面処理後に液残り模様が発現する場合があった。
すなわち、表面処理鋼板に求められる美観としては、表面処理された鋼板の表面全体を平面(2次元)的かつ連続的に観察して、鋼板表面が均一に処理されているか否か、一様に処理されているか否か、あるいは光沢度や色調にむらが生じていないか等の観点から評価されるものであるところ、当該方法によっては前記付着物の分布や形態を平面的に捉えることができず、例えば、硫酸成分が筋状ないし帯状となって鋼板表面に付着していても、どのような範囲で分布しているのか、分布に偏りがあるのか等を把握できないのである。このため、付着量が規定値以下であることを確認してから焼鈍および表面処理したところで、筋状ないし帯状の模様となって現れる液残り模様を完全には防げなかった。
また、前記付着物の分布や形態の平面(2次元)的な把握を可能とすべく、計測点を増加させる改善策も考えられるが、前記した成分分析装置は、一般に計測できる単位面積が狭く、しかも得られる付着量のデータは当該単位面積における平均値でしかないので、依然として鋼板表面における前記付着物の分布等を正確には把握できなかった。
Therefore, as another approach, measure the amount of harmful components adhering to the surface of the steel sheet using a component analyzer, and confirm (control) that the amount of adhesion is less than the specified value before annealing and surface treatment. An application method is disclosed (for example, see Patent Document 1).
However, the data obtained by chemical analyzers, X-ray spectroscopic analyzers, etc. is only one point on the surface of the steel sheet, that is, point data at the measurement point, so the distribution and form of the deposits can be accurately grasped. Can not. For this reason, even if the adhesion amount is less than the specified value, a liquid residue pattern may appear after the surface treatment.
That is, as an aesthetics required for the surface-treated steel sheet, the entire surface of the surface-treated steel sheet is observed planarly (two-dimensionally) continuously, and whether or not the steel sheet surface is uniformly treated is determined. It is evaluated from the viewpoint of whether or not it has been processed, or whether the glossiness and color tone are uneven. Depending on the method, the distribution and form of the deposits can be grasped in a plane. For example, even if the sulfuric acid component is streaked or band-like and adheres to the surface of the steel sheet, it is not possible to grasp what range is distributed or whether the distribution is uneven. For this reason, when it was confirmed that the adhesion amount was not more than the specified value and annealing and surface treatment were performed, the liquid remaining pattern that appeared as a streak-like or band-like pattern could not be completely prevented.
Moreover, in order to make it possible to grasp the distribution and form of the deposits in a planar (two-dimensional) manner, an improvement measure for increasing the number of measurement points is conceivable. However, the above-described component analyzer generally has a small unit area that can be measured. Moreover, since the data on the amount of adhesion obtained is only an average value in the unit area, the distribution of the deposit on the steel sheet surface could not be accurately grasped.

また、特許文献1に記載の方法以外としては、同じく焼鈍前の鋼板からサンプル板を採取し、当該サンプル板に焼鈍および電気めっき等の表面処理を施して、当該サンプル板に液残り模様が発現しないことを確認してから、表面処理を行うべき鋼板に焼鈍および表面処理を施す方法も考えられなくはない。
この方法によれば、硫酸成分が筋状ないし帯状となって鋼板表面に付着していれば、サンプル板表面には液残り模様が発現し、これを目視によって容易に確認できるので、特許文献1に記載の方法よりも確実に液残り模様の発現を予測できる。すなわち、サンプル板表面に液残り模様が発現しなければ、安心して焼鈍ならびに表面処理を行うことができる一方、サンプル板表面に液残り模様が発現した場合には、前処理工程における洗浄不備に迅速に対応できる。
しかしながら、サンプル板用の焼鈍設備および表面処理設備を新たに設ける必要があり、設備的にもコスト的にも現実的な手法ではないのである。
特開平10−317180号公報
In addition, except for the method described in Patent Document 1, a sample plate is similarly collected from a steel plate before annealing, and surface treatment such as annealing and electroplating is performed on the sample plate, and a liquid residue pattern appears on the sample plate. A method of annealing and surface treatment on the steel sheet to be subjected to surface treatment after confirming that it does not occur is also unthinkable.
According to this method, if the sulfuric acid component is in the form of a streak or strip and adheres to the surface of the steel plate, a liquid residue pattern appears on the surface of the sample plate, and this can be easily confirmed visually. The expression of the liquid residue pattern can be predicted more reliably than the method described in 1. In other words, if a liquid residue pattern does not appear on the surface of the sample plate, annealing and surface treatment can be performed with peace of mind. On the other hand, if a liquid residue pattern appears on the surface of the sample plate, the cleaning process in the pretreatment process can be performed quickly. It can correspond to.
However, it is necessary to newly provide an annealing facility and a surface treatment facility for the sample plate, which is not a practical method in terms of facilities and cost.
Japanese Patent Laid-Open No. 10-317180

すなわち、液残り模様の発現を抜本的に解決するためには、いかにリンス洗浄液に含まれる有害成分を減少させるかにかかっているところ、純水の使用はコスト的に難しいので、有害成分の一つである硫酸イオンを含み、しかもその濃度が気象条件等の外的環境によって大きく変動してしまう工業用水を使用せざるを得ないのである。
また、たとえ気象条件等の外的環境に恵まれて硫酸イオン濃度が低い状態にあったとしても、リンガーロールの損傷や磨耗等によって液切りが適正に行われないと、液残り模様が発現してしまう場合もある。そして、ゴム製のリンガーロールは鋼板の鋭利な端部でキズが付き易いので、なおさら液残り模様が発現しやすくなる。
In other words, in order to drastically resolve the appearance of the liquid residue pattern, it depends on how harmful components contained in the rinse cleaning solution are reduced. Therefore, it is necessary to use industrial water that contains sulfate ions, and the concentration of which varies greatly depending on the external environment such as weather conditions.
In addition, even if blessed with the external environment such as weather conditions, even if the sulfate ion concentration is low, if the drainage is not performed properly due to damage or wear of the ringer roll, a liquid residue pattern will appear. Sometimes it ends up. And since the rubber ringer roll is easily scratched at the sharp end of the steel plate, the liquid remaining pattern is more likely to appear.

一方、工業用水や容易にキズが付いてしまうゴム製のリンガーロールを使用せざるを得ないとはいっても、少なくとも表面処理後に液残り模様が発現することの確証を得る手段が存在したならば、使用水量を増加させたり、硫酸イオン濃度を強制的に低下させたり、あるいはリンガーロールを交換する等の対応もできたところ、設備的にもコスト的にも現実的といえる手段が存在しなかったために、表面処理後の鋼板表面に液残り模様が発現するまで前記対応が遅れ、その結果として、原板のみならず表面処理等に要した作業自体までもが無駄となったのである。
さらには、純水を使わず工業用水のみの洗浄であっても条件が揃うときには液残り模様の発現防止に一定の効果を発揮することから、少なくとも表面処理後に液残り模様が発現しないことの確証を得る手段が存在したならば、安心してリンス洗浄処理や表面処理等を行うこともできたところ、設備的にもコスト的にも現実的といえる手段が存在しなかったために、過剰な洗浄等に頼らざるを得なかったのである。
On the other hand, if you have to use industrial water or rubber ringer rolls that easily get scratched, if there is a means to at least confirm that the liquid residue pattern will appear after the surface treatment Measures such as increasing the amount of water used, forcibly lowering the sulfate ion concentration, or replacing the ringer roll were not possible, but there was no means that was realistic in terms of equipment and cost. For this reason, the response is delayed until a liquid residue pattern appears on the surface of the steel plate after the surface treatment, and as a result, not only the original plate but also the work itself required for the surface treatment is wasted.
Furthermore, even if cleaning is performed only with industrial water without using pure water, it has a certain effect in preventing the appearance of residual liquid patterns when conditions are met. If there was a means to obtain the product, rinse cleaning and surface treatment could be performed with peace of mind, but there was no means that could be said to be realistic in terms of equipment and cost, so excessive cleaning, etc. I had to rely on it.

本発明の解決すべき課題は、このような背景のもと工業用水をリンス洗浄液として使用しながらも、液残り模様の発現を防止して、外観ならびに製品歩留まりに優れた電気めっき鋼板または化成処理鋼板を製造できる方法およびその装置を提供することである。
さらには、かつて設備的にもコスト的にも現実的といえる手段が存在しなかった、液残り模様が発現するか否かを目視によって容易に確認できる鋼板表面の清浄性確認装置を提供することである。
The problem to be solved by the present invention is that an electroplated steel sheet or a chemical conversion treatment that prevents the appearance of a liquid residue pattern and is excellent in appearance and product yield while using industrial water as a rinse cleaning liquid under such a background. It is providing the method and apparatus which can manufacture a steel plate.
Furthermore, the present invention provides an apparatus for confirming the cleanliness of a steel sheet surface, in which there is no means that can be said to be realistic in terms of equipment and costs, and whether or not a liquid residue pattern can be easily confirmed visually. It is.

本発明者は、硫酸イオンを含み、しかもその濃度が気象条件等の外的環境によって大きく変動する工業用水を使用せざるを得ないという制約の下、いかにして液残り模様の発現を防ぐことができるかについて種々の実験的検討をしたところ、以下の知見を得た。
(A)工業用水は有害成分である硫酸イオンを含み、しかも気象条件等の外的環境によってその濃度が大きく変動するが、硫酸イオン濃度が低い場合には、液残り模様の発現防止に一定の効果を奏すること。特に硫酸イオン濃度が10ppm以下のときに、所定の効果を発揮すること。
(B)ただし、工業用水中の硫酸イオン濃度が低い場合であっても、リンガーロールの損傷等によって液切りが不十分になると液残り模様が発現する場合があるので、なんらかの新たな手段を開発することにより鋼板表面の清浄性を確認する必要があること。換言すると、硫酸イオン濃度の上昇やリンガーロールの損傷等を感知できるようにすべきこと。
The present inventor, how to prevent the appearance of the liquid residue pattern under the restriction that industrial water containing sulfate ions and whose concentration greatly varies depending on the external environment such as weather conditions must be used. As a result of various experimental studies on whether or not the above can be achieved, the following findings were obtained.
(A) Industrial water contains sulfate ions, which are harmful components, and its concentration varies greatly depending on the external environment such as weather conditions. Have an effect. In particular, when a sulfate ion concentration is 10 ppm or less, a predetermined effect is exhibited.
(B) However, even if the sulfate ion concentration in industrial water is low, a liquid residue pattern may appear if the drainage is insufficient due to damage of the Ringer roll, etc. It is necessary to confirm the cleanliness of the steel sheet surface by doing. In other words, it should be able to detect an increase in sulfate ion concentration, ringer roll damage, and the like.

以上から本発明者は、工業用水をリンス洗浄液として使用する場合であっても、液切りを十分に行い、かつ焼鈍炉内で鋼板表面に焼き付いた硫酸イオンの分布や形態を目視によって容易に確認することができれば、液残り模様の発現を防止できるという知見に到った。そこで本発明者は、当該新たな手段を開発すべく、数多くの理論検討および実験検討を行った結果、新たに以下の知見を得た。
(C)表面に硫酸イオンが筋状ないし帯状に焼き付いている焼鈍板、換言すると、このまま表面処理を行えば液残り模様が発現する焼鈍板に対して、所定の条件で電解脱脂処理と電解酸洗処理を順次行うと、焼鈍板の表面には液残り模様と極めて類似する模様(以下、擬似模様と称する。)が発現すること。すなわち、当該新たな手段を用いることにより、焼鈍後表面処理前の段階において、液残り模様の発現有無の予測ならびに硫酸イオン濃度の上昇またはリンガーロールの損傷等を感知できること。
From the above, even when the industrial water is used as the rinsing cleaning liquid, the present inventor performs sufficient drainage and easily confirms the distribution and form of sulfate ions seized on the steel sheet surface in the annealing furnace. If it can be done, it came to the knowledge that expression of a liquid residue pattern can be prevented. Therefore, the present inventor has obtained the following new knowledge as a result of conducting numerous theoretical and experimental studies in order to develop the new means.
(C) An electrolytic degreasing treatment and an electrolytic acid under predetermined conditions for an annealed plate in which sulfate ions are baked into stripes or strips on the surface, in other words, an annealed plate in which a liquid residue pattern appears if the surface treatment is performed as it is. When the washing process is sequentially performed, a pattern (hereinafter referred to as a pseudo pattern) very similar to the liquid remaining pattern appears on the surface of the annealed plate. That is, by using the new means, it is possible to detect the presence or absence of a liquid residue pattern and to detect an increase in sulfate ion concentration or ringer roll damage in the stage before the surface treatment after annealing.

上記の知見に基づき、本発明者は、工業用水をリンス洗浄液として使用しながらも、液残り模様の発現を防止して、外観ならびに製品歩留まりに優れた電気めっき鋼板または化成処理鋼板を製造できる方法およびその装置、ならびに、かつては設備的にもコスト的にも現実的といえる手段が存在しなかった、液残り模様が発現するか否かを目視によって容易に確認できる鋼板表面の清浄性確認装置に想到した。その要旨とするところは以下の通りである。   Based on the above knowledge, the present inventor is able to produce an electroplated steel sheet or a chemical conversion treated steel sheet having excellent appearance and product yield by preventing the appearance of a liquid residue pattern while using industrial water as a rinse cleaning liquid. And its apparatus, and a device for confirming the cleanliness of the surface of a steel sheet, in which there is no means that can be said to be realistic in terms of equipment and cost, and whether or not a liquid residue pattern can be easily observed visually. I came up with it. The gist is as follows.

(1)冷延鋼板にアルカリ洗浄と酸洗のいずれか一方または双方の洗浄処理と、前記洗浄処理で付着した洗浄液を鋼板表面から除去するリンス洗浄処理と、リンス洗浄処理で付着したリンス洗浄液を鋼板表面から除去する液切り処理とを行う連続焼鈍ラインの前処理工程と、前処理された冷延鋼板を連続焼鈍する焼鈍工程と、焼鈍された鋼板に電気めっきと化成処理のいずれか一方または双方の表面処理を行う表面処理工程とを備えた表面処理鋼板の製造方法において、前記焼鈍工程と表面処理工程の間に、表面処理前の鋼板からサンプルを採取し、サンプルに電解脱脂処理と電解酸洗処理を順次行い、サンプル表面に所定の模様が発現するか否かにより鋼板表面の清浄性を評価する清浄性評価工程を更に備えたことを特徴とする外観に優れた表面処理鋼板の製造方法。 (1) A cleaning treatment for either one or both of alkaline cleaning and pickling on a cold-rolled steel sheet, a rinsing cleaning process for removing the cleaning liquid adhering to the cleaning process from the steel sheet surface, and a rinsing cleaning liquid adhering to the rinsing cleaning process Either a pretreatment step of a continuous annealing line for performing a liquid draining treatment to be removed from the steel plate surface, an annealing step of continuously annealing the pretreated cold-rolled steel plate, and electroplating and chemical conversion treatment on the annealed steel plate or In the method of manufacturing a surface-treated steel sheet having a surface treatment process for performing both surface treatments, a sample is taken from the steel sheet before the surface treatment between the annealing process and the surface treatment process, and the sample is subjected to electrolytic degreasing treatment and electrolysis. Excellent in appearance, characterized by further comprising a cleanliness evaluation step that evaluates the cleanliness of the surface of the steel sheet depending on whether a predetermined pattern appears on the sample surface by sequentially performing pickling treatment A method for producing a surface-treated steel sheet.

(2)前記清浄性評価工程において所定の模様が発現した場合には、連続焼鈍ラインの前処理工程におけるリンス洗浄能力と液切り能力のいずれか一方または双方を強化することを特徴とする前記(1)に記載の外観に優れた表面処理鋼板の製造方法。
(3)前記リンス洗浄能力の強化が、硫酸イオン濃度が10ppm以下のリンス洗浄液を用いてリンス洗浄することを特徴とする前記(2)に記載の外観に優れた表面処理鋼板の製造方法。
(2) When the predetermined pattern is developed in the cleanliness evaluation step, either or both of the rinse cleaning ability and the liquid draining ability in the pretreatment step of the continuous annealing line are strengthened. The manufacturing method of the surface treatment steel plate excellent in the external appearance as described in 1).
(3) The method for producing a surface-treated steel sheet having excellent appearance according to (2) above, wherein the rinse cleaning ability is enhanced by using a rinse cleaning solution having a sulfate ion concentration of 10 ppm or less.

(4)前記電解脱脂処理と電解酸洗処理を30〜240C/dmのクーロン量で行うことを特徴とする前記(1)〜(3)のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
(5)前記電解脱脂処理と電解酸洗処理を10〜35℃の温度で行うことを特徴とする前記(1)〜(4)のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
(6)前記電解脱脂処理を、NaOH濃度が5〜50g/Lの電解脱脂液を用いて行うことを特徴とする前記(1)〜(5)のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
(7)前記電解酸洗処理を、HSO濃度が30〜50g/Lの電解酸洗液を用いて行うことを特徴とする前記(1)〜(5)のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
(4) The surface excellent in appearance according to any one of (1) to (3), wherein the electrolytic degreasing treatment and the electrolytic pickling treatment are performed at a coulomb amount of 30 to 240 C / dm 2. A method for producing a treated steel sheet.
(5) The surface-treated steel sheet having excellent appearance according to any one of (1) to (4), wherein the electrolytic degreasing treatment and the electrolytic pickling treatment are performed at a temperature of 10 to 35 ° C. Production method.
(6) The electrolytic degreasing treatment is performed using an electrolytic degreasing solution having a NaOH concentration of 5 to 50 g / L, and the appearance according to any one of (1) to (5) is excellent. Manufacturing method of surface-treated steel sheet.
(7) The electrolytic pickling treatment is performed using an electrolytic pickling solution having an H 2 SO 4 concentration of 30 to 50 g / L, according to any one of (1) to (5), For producing a surface-treated steel sheet having an excellent appearance.

(8)電気めっき前または化成処理前の鋼板の表面清浄性を目視で確認するための装置であって、鋼板から採取したサンプルを電解脱脂する電解脱脂処理槽と、サンプルを電解酸洗する電解酸洗処理槽と、前記電解脱脂処理槽に収容された電解脱脂液または前記電解酸洗処理槽に収容された電解酸洗液に浸漬されたサンプルと各処理槽が各々具備する電極との間に直流電圧を印加する電源を備えたことを特徴とする鋼板表面の清浄性確認装置。
(9)さらに、前記サンプルを前記電解脱脂液または電解酸洗液の液面に対して垂直に保持する手段と、保持したサンプルを水平方向に移動する手段と、保持したサンプルを昇降する手段を備えたことを特徴とする前記(8)に記載の鋼板表面の清浄性確認装置。
(8) An apparatus for visually confirming the surface cleanliness of a steel plate before electroplating or chemical conversion treatment, an electrolytic degreasing bath for electrolytically degreasing a sample taken from the steel plate, and electrolysis for electrolytic pickling of the sample Between a pickling bath, a sample immersed in an electrolytic degreasing solution housed in the electrolytic degreasing bath or an electrolytic pickling bath housed in the electrolytic pickling bath, and an electrode included in each processing bath A device for confirming the cleanliness of the surface of a steel sheet, comprising a power source for applying a DC voltage.
(9) Furthermore, means for holding the sample perpendicular to the surface of the electrolytic degreasing solution or electrolytic pickling solution, means for moving the held sample in a horizontal direction, and means for moving the held sample up and down The apparatus for confirming the cleanliness of the surface of a steel sheet according to (8), characterized by comprising:

(10)前記電解脱脂処理槽と電解酸洗処理槽における電解処理を30〜240C/dmのクーロン量で行うことを特徴とする前記(8)または(9)に記載の鋼板表面の清浄性確認装置。
(11)前記電解脱脂液と電解酸洗液の温度が10〜35℃であることを特徴とする前記(8)〜(10)のいずれか1項に記載の鋼板表面の清浄性確認装置。
(12)前記電解脱脂液のNaOH濃度が5〜50g/Lであることを特徴とする前記(8)〜(11)のいずれか1項に記載の鋼板表面の清浄性確認装置。
(13)前記電解酸洗液のHSO濃度が30〜50g/Lであることを特徴とする前記(8)〜(11)のいずれか1項に記載の鋼板表面の清浄性確認装置。
(14)前記(8)〜(13)のいずれか1項に記載の鋼板表面の清浄性確認装置を、連続焼鈍ラインの出側に配置したことを特徴とする外観に優れた表面処理鋼板の製造装置。
(10) The cleanliness of the steel sheet surface as described in (8) or (9) above, wherein the electrolytic treatment in the electrolytic degreasing treatment tank and the electrolytic pickling treatment tank is performed at a Coulomb amount of 30 to 240 C / dm 2 . Confirmation device.
(11) The apparatus for confirming the cleanliness of the steel sheet surface according to any one of (8) to (10), wherein the temperature of the electrolytic degreasing solution and the electrolytic pickling solution is 10 to 35 ° C.
(12) NaOH concentration of the electrolytic degreasing solution is 5 to 50 g / L, the steel sheet surface cleanliness confirmation device according to any one of (8) to (11) above.
(13) The apparatus for confirming the cleanliness of the steel sheet surface according to any one of (8) to (11), wherein the electrolytic pickling solution has a H 2 SO 4 concentration of 30 to 50 g / L. .
(14) A surface-treated steel sheet excellent in appearance, wherein the apparatus for confirming the cleanliness of the steel sheet surface according to any one of (8) to (13) is disposed on the exit side of the continuous annealing line. Manufacturing equipment.

焼鈍工程と表面処理工程との間に新たに鋼板表面の清浄性評価工程を設けた本発明に係る表面処理鋼板の製造方法およびその装置によれば、たとえ工業用水やリンガーロールを使用しても、焼鈍後表面処理前の段階において確実かつ容易に、液残り模様が発現するか否かを予測できるので、外観ならびに製品歩留まりに優れた電気めっき鋼板または化成処理鋼板を安定して製造できる。
具体的には、焼鈍後表面処理前の段階において液残り模様が発現するとの結果を得た場合には、表面処理作業を速やかに中止でき、従来技術では実施せざるを得なかった無駄な作業を未然に防ぐことができる。また、上工程であるリンス洗浄処理で使用する工業用水を増加させたり、リンガーロールを交換する等の再発を防止するための対応を迅速に採ることができることから、表面処理鋼板の外観品質ならびに製品歩留まりの改善を図ることができる。
一方、液残り模様が発現しないとの結果を得た場合には、次工程である表面処理を安心して行うことができ、液残り模様の発現しない外観に優れた表面処理鋼板を安定して得ることができる。また、当該模様が発現しないとの結果は、リンス洗浄処理工程における洗浄処理能力が正常であることを裏付けるものとなるから、熟練作業者の経験やノウハウに頼ることなく、経験の浅い作業者であっても適正な洗浄条件で操業することができ、操業の安定化ならびにリンス洗浄水のコスト削減を図ることができる。
これは、連続焼鈍ラインおよび電気めっきまたは化成処理ラインの長時間安定操業、ひいては近年ユーザからの要求がますます高まっている均質かつ美麗な外観品質に資するものであり、また、美麗な表面性状を有する表面処理鋼板を安定して製造できるので、製造品質に与える影響ならびに経済的効果は極めて大きく、鉄鋼業界のみならず、その産業上利用性は極めて甚大である。
According to the method and apparatus for producing a surface-treated steel sheet according to the present invention in which a steel sheet surface cleanliness evaluation process is newly provided between the annealing process and the surface treatment process, even if industrial water or a ringer roll is used. In addition, since it is possible to reliably and easily predict whether or not the liquid residue pattern will appear in the stage after the surface treatment after annealing, it is possible to stably produce an electroplated steel plate or a chemical conversion treated steel plate excellent in appearance and product yield.
Specifically, when the result that the liquid residue pattern appears in the stage after the surface treatment after annealing, the surface treatment work can be stopped quickly, and wasteful work that had to be performed by the conventional technology Can be prevented in advance. In addition, it is possible to quickly take measures to prevent recurrence such as increasing the industrial water used in the rinsing cleaning process, which is the upper process, and replacing the ringer roll. Yield can be improved.
On the other hand, when the result that the liquid residue pattern does not appear is obtained, the surface treatment as the next process can be performed with confidence, and the surface-treated steel sheet having an excellent appearance without the liquid residue pattern is obtained stably. be able to. In addition, the result that the pattern does not appear confirms that the cleaning performance in the rinsing cleaning process is normal, so it is possible for an inexperienced worker to rely on the experience and know-how of a skilled worker. Even if it exists, it can be operated under appropriate cleaning conditions, and the operation can be stabilized and the cost of rinse water can be reduced.
This contributes to the long-term stable operation of continuous annealing lines and electroplating or chemical conversion treatment lines, and to the homogeneous and beautiful appearance quality that has been increasingly demanded by users in recent years. Since the surface-treated steel sheet can be manufactured stably, the influence on the manufacturing quality and the economic effect are extremely large, and the industrial utility as well as the steel industry is extremely large.

以下、図2〜図4を参照して、本発明を実施するための最良の形態を説明する。
図2は、本発明に係る表面処理鋼板の製造方法の1態様を示すフローチャートであり、連続焼鈍ラインの前処理工程、焼鈍工程、そして本発明の最大の特徴である清浄性評価工程、および表面処理工程とから構成される。
Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
FIG. 2 is a flowchart showing one embodiment of a method for producing a surface-treated steel sheet according to the present invention, a pretreatment process of a continuous annealing line, an annealing process, and a cleanliness evaluation process that is the greatest feature of the present invention, and the surface And processing steps.

連続焼鈍ラインの前処理工程は、防錆油や調質圧延油等の油脂分を鋼板表面から除去するアルカリ洗浄処理と、鋼板表面に存在する無機系の汚れ、例えば、錆、酸化皮膜(スケール)、スマット等を除去する酸洗処理と、これらの洗浄処理で使用した洗浄液を鋼板表面から除去するリンス洗浄処理、さらにはリンス洗浄処理で付着したリンス洗浄液を鋼板表面から除去する液切り処理とから構成される。
なお、図2に示すように、本発明に係る表面処理鋼板の製造方法においては、酸洗処理を含まない場合も含む。
The pre-treatment process of the continuous annealing line consists of alkali cleaning treatment to remove oils and fats such as rust preventive oil and temper rolling oil from the steel sheet surface, and inorganic dirt existing on the steel sheet surface such as rust and oxide film (scale ), Pickling treatment for removing smut, etc., rinsing washing treatment for removing the washing liquid used in these washing treatments from the steel plate surface, and further a rinsing treatment for removing the rinsing washing liquid adhering to the rinsing washing treatment from the steel plate surface Consists of
In addition, as shown in FIG. 2, in the manufacturing method of the surface treatment steel plate which concerns on this invention, the case where a pickling process is not included is also included.

アルカリ洗浄処理で使用する洗浄液のアルカリ塩としては、特に限定されるものではなく、水酸化ナトリウム、炭酸ナトリウム、ケイ酸ナトリウム、リン酸ナトリウム、シアン化ナトリウム、ホウ酸ナトリウム等のいずれか一つまたはこれらの混合物を用いることができる。
なお、必要に応じて、アルカリ洗浄液にアニオン界面活性剤やノニオン界面活性剤を添加することにより洗浄力を向上させることができる。
また、洗浄方法についても特に限定されるものではなく、浸漬洗浄、ブラシ洗浄、電解洗浄、スプレー洗浄等のいずれか一つまたはこれらを組み合わせて用いることができる。
The alkali salt of the cleaning solution used in the alkali cleaning treatment is not particularly limited, and any one of sodium hydroxide, sodium carbonate, sodium silicate, sodium phosphate, sodium cyanide, sodium borate and the like or Mixtures of these can be used.
If necessary, the detergency can be improved by adding an anionic surfactant or a nonionic surfactant to the alkaline cleaning liquid.
Also, the cleaning method is not particularly limited, and any one of immersion cleaning, brush cleaning, electrolytic cleaning, spray cleaning and the like can be used in combination.

酸洗処理で使用する洗浄液としても、特に限定されるものではなく、塩酸、硫酸、硝酸等のいずれか一つまたはこれらの混合物を用いることができる。
なお、必要に応じて酸洗抑制剤(インヒビタ)を添加することにより、鋼板表面の肌荒れを防ぎ、比較的均一な脱錆、脱スケールを行うことができる。また、酸洗促進剤を添加することにより、鋼板表面のぬれ性を向上させることができる。
洗浄方法についても特に限定されるものではなく、浸漬洗浄、電解洗浄、機械的方法等のいずれか一つまたはこれらを組み合わせて用いることができる。
The cleaning liquid used in the pickling treatment is not particularly limited, and any one of hydrochloric acid, sulfuric acid, nitric acid, or a mixture thereof can be used.
In addition, by adding a pickling inhibitor (inhibitor) as necessary, the surface of the steel sheet can be prevented from roughening and relatively uniform derusting and descaling can be performed. Moreover, the wettability of the steel plate surface can be improved by adding a pickling accelerator.
The cleaning method is not particularly limited, and any one of immersion cleaning, electrolytic cleaning, mechanical method, or the like can be used in combination.

リンス洗浄処理で使用するリンス洗浄液としては、前記したように純水はもちろんのこと、工業用水やイオン交換水等を用いることができる。
そして、当然のことながら液残り模様の発現を抑止するには、リンス洗浄液の硫酸イオン濃度を低減させることが有効であり、望ましくは、硫酸イオン濃度を10ppm以下にすることが好ましい。
これは、本発明者が数々の実験および解析を行った結果、初めて明らかにした知見であり、その内容は以下のとおりである。
As the rinse cleaning liquid used in the rinse cleaning treatment, as described above, not only pure water but also industrial water, ion-exchanged water, and the like can be used.
As a matter of course, it is effective to reduce the sulfate ion concentration of the rinse cleaning solution in order to suppress the appearance of the remaining liquid pattern, and it is preferable to set the sulfate ion concentration to 10 ppm or less.
This is a knowledge that has been clarified for the first time as a result of numerous experiments and analyzes by the present inventor, and the contents thereof are as follows.

前記したように液残り模様の発現要因は、リンス洗浄液に含まれる硫酸イオンとリンガーロールの損傷等による液切り不全であるが、本発明者は、液切りが適正に行われるとした場合の、液残り模様が発現しない硫酸イオン濃度の限界値を調査すべく、以下の実験を行った。なお、図3は当該調査方法を示す模式図である。
まず、板サイズがt0.2mm×W900mmの冷延鋼板に対し、以下の条件で電解脱脂および電解酸洗を施し、純水を用いてこれらの処理で用いた洗浄液を完全に除去した。
[電解脱脂条件]
NaOH:20g/L、液温度:55℃、電流密度:20A/dm、1.3秒通電
[電解酸洗条件]
SO:20g/L、液温度:25℃、電流密度:20A/dm、1.3秒通電
As described above, the expression factor of the remaining liquid pattern is liquid drainage failure due to damage of sulfate ion and Ringer roll contained in the rinse liquid, but the present inventor has said that liquid draining is performed properly, The following experiment was conducted to investigate the limit value of the sulfate ion concentration at which the liquid residue pattern does not appear. FIG. 3 is a schematic diagram showing the investigation method.
First, a cold rolled steel sheet having a plate size of t0.2 mm × W900 mm was subjected to electrolytic degreasing and electrolytic pickling under the following conditions, and the cleaning liquid used in these treatments was completely removed using pure water.
[Electrolytic degreasing conditions]
NaOH: 20 g / L, liquid temperature: 55 ° C., current density: 20 A / dm 2 , energization for 1.3 seconds [electrolytic pickling conditions]
H 2 SO 4 : 20 g / L, liquid temperature: 25 ° C., current density: 20 A / dm 2 , energization for 1.3 seconds

その後、前記鋼板に対し、硫酸イオン濃度が5、10、25、50ppmのリンス洗浄液を図3に示すように片面あたり5g/m付着させ、その後、5%H残N、露点:−40℃の雰囲気中で30秒で板温度650℃に昇温し、その後30秒間650℃で保持した。次いで、80℃まで冷却し、脱炉した。
その後、脱炉した焼鈍板に対し、以下のめっき条件で3g/LのSnめっきを片面に施し、液残り模様が発現するか否かを観察した。
[めっき条件]
Snイオン濃度:20g/L、液温度:50℃、電流密度:5A/dm、11秒通電
Thereafter, a rinse solution having a sulfate ion concentration of 5, 10, 25, and 50 ppm was attached to the steel sheet at 5 g / m 2 per side as shown in FIG. 3, and then 5% H 2 residual N 2 , dew point: − The plate temperature was raised to 650 ° C. in 30 seconds in an atmosphere of 40 ° C., and then maintained at 650 ° C. for 30 seconds. Subsequently, it cooled to 80 degreeC and de-furnaceed.
Thereafter, 3 g / L of Sn plating was applied to one surface of the annealed annealed plate under the following plating conditions, and it was observed whether or not a liquid residue pattern was developed.
[Plating conditions]
Sn ion concentration: 20 g / L, liquid temperature: 50 ° C., current density: 5 A / dm 2 , energization for 11 seconds

その結果、硫酸イオン濃度が10ppm以下の鋼板については外観品質に問題は生じなかったが、硫酸イオン濃度が25ppmと50ppmのリンス洗浄液を使用した鋼板については液残り模様が発現し、表面処理鋼板の外観品質が大きく損なわれた。   As a result, there was no problem in the appearance quality for the steel plate having a sulfate ion concentration of 10 ppm or less, but a liquid residue pattern was developed for the steel plate using the rinse solution having a sulfate ion concentration of 25 ppm and 50 ppm. Appearance quality was greatly impaired.

また、前記焼鈍板に対し、電気亜鉛めっきラインで亜鉛めっきを5g/m片面に施した場合やティンフリースチールラインでクロムめっきを100mg/m片面に施した場合についても同様の実験をしたところ、硫酸イオン濃度が10ppm以下の鋼板については外観品質に問題は生じなかったが、硫酸イオン濃度が25ppmと50ppmのリンス洗浄液を使用した鋼板については液残り模様が発現し、表面処理鋼板の外観品質が大きく損なわれた。
同様に、前記焼鈍板に対し、りん酸処理を8mg/m片面に施した場合やクロメート処理を8mg/m片面に施した場合についても同様の実験をしたところ、Snめっき等を施した場合と同様の結果となった。
In addition, the same experiment was performed on the annealed plate when zinc plating was applied to one side of 5 g / m 2 by an electrogalvanization line or when chromium plating was applied to one side of 100 mg / m 2 by a tin-free steel line. However, there was no problem in appearance quality for the steel sheet having a sulfate ion concentration of 10 ppm or less, but a liquid residue pattern was developed in the steel sheet using the rinse solution having a sulfate ion concentration of 25 ppm and 50 ppm, and the appearance of the surface-treated steel sheet. Quality was greatly impaired.
Similarly, when the same treatment was performed on the annealed plate when phosphoric acid treatment was performed on one side of 8 mg / m 2 or chromate treatment was performed on one side of 8 mg / m 2 , Sn plating or the like was performed. The result was similar to the case.

したがって、リンス洗浄処理で使用するリンス洗浄液としては、硫酸イオン濃度を10ppm以下にすることが好ましい。
なお、硫酸イオン濃度を低下させる方法としては、特に限定されるものではないが、連続焼鈍ラインの前処理工程のリンスタンク出側に2対以上のリンガーロールを設置し、最終リンガーロールの下段において鋼板に、板巾方向にノズルで純水をスプレーすることで、鋼板に付着したリンス洗浄液の硫酸イオン濃度を低下することができる。
Therefore, it is preferable to set the sulfate ion concentration to 10 ppm or less as the rinse cleaning liquid used in the rinse cleaning process.
In addition, although it does not specifically limit as a method to reduce a sulfate ion density | concentration, 2 pairs or more of ringer rolls are installed in the rinse tank exit side of the pretreatment process of a continuous annealing line, and in the lower stage of the final ringer roll By spraying pure water with a nozzle in the sheet width direction on the steel sheet, the sulfate ion concentration of the rinse cleaning liquid adhering to the steel sheet can be reduced.

液切り処理としても特に限定されるものではなく、一般的に用いられるゴム製のリンガーロールで液切りを行ってもよいし、前記したようにリンガーロールの設置台数を増加させることにより液切り強化を図ることも可能である。
また、前記したようにリンガーロールの上段下段に関わらず、純水等のスプレー洗浄を行うことによりリンス洗浄能力を補助的に強化することができる。
The liquid draining process is not particularly limited, and liquid draining may be performed with a rubber ringer roll that is generally used. As described above, liquid draining is enhanced by increasing the number of ringer rolls installed. It is also possible to plan.
Further, as described above, regardless of the upper and lower stages of the ringer roll, the rinse cleaning ability can be supplementarily enhanced by performing spray cleaning with pure water or the like.

焼鈍炉あるいは焼鈍条件についても特に限定されるものではなく、一般的な冷延鋼板あるいは表面処理鋼板の製造工程で用いられる連続焼鈍ラインを用いることができる。   An annealing furnace or annealing conditions are not particularly limited, and a continuous annealing line used in a manufacturing process of a general cold-rolled steel sheet or surface-treated steel sheet can be used.

次に、本発明に係る表面処理鋼板の製造方法の最大の特徴である清浄性評価工程について説明する。
本工程においては、焼鈍後表面処理前の鋼板からサンプルを採取し、当該サンプルに電解脱脂処理と電解酸洗処理を順次行い、サンプル表面に液残り模様と極めて類似する模様、すなわち疑似模様が発現するか否かを確認する。
これも、本発明者が数々の実験および解析を行った結果、表面に硫酸イオンが筋状ないし帯状に焼き付いている焼鈍板、換言すると、このまま表面処理を行えば液残り模様が発現する焼鈍板に対して、以下の条件で電解脱脂処理と電解酸洗処理を順次行うと、焼鈍板の表面には疑似模様が発現することを初めて知見したことに基づくものである。
Next, the cleanliness evaluation process, which is the greatest feature of the method for producing a surface-treated steel sheet according to the present invention, will be described.
In this process, a sample is collected from the steel sheet after annealing and before surface treatment, and the sample is subjected to electrolytic degreasing treatment and electrolytic pickling treatment in sequence, and a pattern very similar to the liquid residue pattern, that is, a pseudo pattern, appears on the sample surface. Confirm whether or not to do.
This is also the result of numerous experiments and analyzes by the inventor. As a result, an annealed plate in which sulfate ions are burned in the form of stripes or strips on the surface, in other words, an annealed plate in which a liquid residue pattern appears if surface treatment is performed as it is On the other hand, this is based on the first finding that a pseudo pattern appears on the surface of the annealed plate when electrolytic degreasing treatment and electrolytic pickling treatment are sequentially performed under the following conditions.

なお、表1〜3は当該実験結果を示したものであるが、これは、リンガーロール出側において、長手方向から見た場合に左右対称になるように、故意に硫酸イオン濃度が0〜50ppmのリンス洗浄液をスプレー散布し、焼鈍炉の出側でコイルを長手方向に2分割し、片方のコイル(以下、本コイルと称する。)に対しては電気Snめっきラインでめっきを施し、もう片方のコイル(以下、評価コイルと称する。)に対しては、表1〜3に示す条件で電解脱脂処理および電解酸洗処理を行い、その後、双方のコイルを分割前の形になるように並べて比較観察した場合に、左右対称に液残り模様と擬似模様が発現するか否かについて実験したものである。
なお、前処理工程における電解脱脂条件・電解酸洗条件、および純水を用いてこれらの処理で用いた洗浄液を完全に除去したこと、さらに、本コイルに対する焼鈍条件・Snめっき条件は、前記した液残り模様が発現しない硫酸イオン濃度の限界値調査で用いた条件と同一である。
さらに、当該実験の後、電気亜鉛めっきライン、ティンフリースチールライン、りん酸処理ライン、およびクロメート処理ラインを用いて、同様の実験をしたところ、電気Snめっきラインと同様の結果になったので、表1〜3で代用する。
ただし、前記した液残り模様が発現しない硫酸イオン濃度の限界値調査においては、液残り模様の発現要因の一つである液切り不全を調査目的のため実験条件から外したが、本実験においては、液切り不全の影響を調査するため、鋼板を長手方向から見た場合に左右対称に筋がつくように、リンガーロールに対して故意にキズを設けている。
Tables 1 to 3 show the results of the experiment. On the ringer roll exit side, the sulfate ion concentration is intentionally 0 to 50 ppm so as to be symmetrical when viewed from the longitudinal direction. Spray the rinsing cleaning solution, and divide the coil into two in the longitudinal direction on the exit side of the annealing furnace, and apply plating to one coil (hereinafter referred to as this coil) with the electric Sn plating line, and the other The coils (hereinafter referred to as evaluation coils) are subjected to electrolytic degreasing treatment and electrolytic pickling treatment under the conditions shown in Tables 1 to 3, and then both coils are arranged so as to be in the form before division. This is an experiment on whether or not the liquid remaining pattern and the pseudo pattern appear symmetrically in the comparative observation.
The electrolytic degreasing conditions, the electrolytic pickling conditions in the pretreatment process, and the cleaning solution used in these treatments using pure water were completely removed, and the annealing conditions and Sn plating conditions for this coil were as described above. The conditions are the same as those used in the limit value investigation of the sulfate ion concentration at which the liquid residue pattern does not appear.
Furthermore, after the experiment, when the same experiment was performed using an electrogalvanizing line, a tin-free steel line, a phosphoric acid treatment line, and a chromate treatment line, the result was the same as that of the electric Sn plating line. It substitutes in Tables 1-3.
However, in the limit value investigation of the sulfate ion concentration at which the liquid residue pattern does not appear, liquid drainage failure, which is one of the causes of the liquid residue pattern, was removed from the experimental conditions for the purpose of investigation, but in this experiment In order to investigate the influence of liquid drainage failure, a flaw is intentionally provided on the ringer roll so that when the steel plate is viewed from the longitudinal direction, the lines are symmetrically formed.

電解脱脂処理と電解酸洗処理は、30〜240C/dmのクーロン量(電流密度×電解時間)で行うことが望ましい。
表1の実験結果に示すように、30C/dm未満では脱脂・酸洗能力が低く、本コイルでは液残り模様が発現するのに評価コイルでは疑似模様が発現しない。240C/dmを超えると過酸洗となり、発現した疑似模様までも酸洗することになり目視で確認することができない。
なお、電解脱脂処理と電解酸洗処理は、同一のクーロン量で行うことが望ましい。脱脂と酸洗の電解条件を変えると制御が複雑になり、また、電解用電源が2セット必要となり装置規模が大きくなる。
The electrolytic degreasing treatment and the electrolytic pickling treatment are desirably performed at a Coulomb amount (current density × electrolysis time) of 30 to 240 C / dm 2 .
As shown in the experimental results of Table 1, the degreasing / pickling ability is low at less than 30 C / dm 2 , and the liquid remaining pattern appears in this coil, but the pseudo pattern does not appear in the evaluation coil. If it exceeds 240 C / dm 2 , it becomes per-acid pickling, and even the pseudo pattern that appears is pickled and cannot be visually confirmed.
The electrolytic degreasing treatment and the electrolytic pickling treatment are desirably performed with the same amount of coulomb. If the electrolytic conditions for degreasing and pickling are changed, the control becomes complicated, and two sets of power sources for electrolysis are required, which increases the scale of the apparatus.

Figure 0004523878
Figure 0004523878

電解脱脂処理と電解酸洗処理は、10〜35℃で行うことが望ましい。すなわち、電解脱脂液と電解酸洗液は10〜35℃であることが望ましい。
表1の実験結果に示すように、10℃未満では脱脂・酸洗能力が低く、本コイルでは液残り模様が発現するのに評価コイルでは疑似模様が発現しない。35℃を超えても疑似模様は発現するが、昇温装置が必要となりコストに見合わない。
The electrolytic degreasing treatment and the electrolytic pickling treatment are desirably performed at 10 to 35 ° C. That is, the electrolytic degreasing solution and the electrolytic pickling solution are desirably 10 to 35 ° C.
As shown in the experimental results in Table 1, the degreasing / pickling ability is low at less than 10 ° C., and the liquid remaining pattern appears in this coil, but the pseudo pattern does not appear in the evaluation coil. Even if the temperature exceeds 35 ° C., a pseudo pattern appears, but a temperature raising device is required and it is not worth the cost.

電解脱脂処理については、NaOH濃度が5〜50g/Lの電解脱脂液を用いることが望ましい。
表2の実験結果に示すように、5g/L未満では脱脂能力が低く、本コイルでは液残り模様が発現するのに評価コイルでは疑似模様が発現しない。50g/Lを超えると発泡が激しくなり、泡がサンプル表面に付着して、本コイルでは液残り模様が発現しないにも拘らず評価コイルでは疑似模様が発現してしまう。
For the electrolytic degreasing treatment, it is desirable to use an electrolytic degreasing solution having a NaOH concentration of 5 to 50 g / L.
As shown in the experimental results of Table 2, the degreasing capacity is low at less than 5 g / L, and the liquid remaining pattern appears in this coil, but the pseudo pattern does not appear in the evaluation coil. When it exceeds 50 g / L, foaming becomes intense and bubbles adhere to the surface of the sample. Even though the liquid remaining pattern does not appear in this coil, a pseudo pattern appears in the evaluation coil.

Figure 0004523878
Figure 0004523878

電解酸洗処理については、HSO濃度が30〜50g/Lの電解酸洗液を用いることが望ましい。
表3の実験結果に示すように、30g/L未満では酸洗能力が低く、本コイルでは液残り模様が発現するのに評価コイルでは疑似模様が発現しない。50g/Lを超えると過酸洗となり、発現した疑似模様までも酸洗することになり目視で確認することができない。
For the electrolytic pickling treatment, it is desirable to use an electrolytic pickling solution having a H 2 SO 4 concentration of 30 to 50 g / L.
As shown in the experimental results of Table 3, the pickling ability is low at less than 30 g / L, and the liquid remaining pattern appears in this coil, but the pseudo pattern does not appear in the evaluation coil. When it exceeds 50 g / L, it becomes per-acid wash, and even the pseudo pattern which expressed will be pickled, and it cannot confirm visually.

Figure 0004523878
Figure 0004523878

図4は、本発明に係る鋼板表面の清浄性確認装置2の模式図であり、電気めっき前または化成処理前の鋼板から採取したサンプル1を電解脱脂する電解脱脂処理槽3と、電解脱脂液を洗浄する水洗槽4、サンプルを電解酸洗する電解酸洗処理槽5、および電解酸洗液を洗浄する水洗槽6を備える。
また、当該清浄性確認装置は電源8を備えているので、前記電解脱脂処理槽3に収容された電解脱脂液に浸漬されたサンプル1と電解脱脂処理槽3が具備する電極7との間に直流電圧を印加することができ、これにより鋼板表面の清浄性を確認するための電解脱脂処理を容易に行うことができる。同様に、前記電解酸洗処理槽5に収容された電解酸洗液に浸漬されたサンプル1と電解酸洗処理槽5が具備する電極7との間に直流電圧を印加することができ、これにより鋼板表面の清浄性を確認するための電解酸洗処理を容易に行うことができる。
FIG. 4 is a schematic diagram of a steel sheet surface cleanliness confirmation apparatus 2 according to the present invention, and an electrolytic degreasing bath 3 for electrolytically degreasing a sample 1 collected from a steel plate before electroplating or before chemical conversion treatment, and an electrolytic degreasing solution. A washing tank 4 for washing the sample, an electrolytic pickling treatment tank 5 for electrolytic pickling of the sample, and a washing tank 6 for washing the electrolytic pickling solution.
Moreover, since the said cleanliness confirmation apparatus is equipped with the power supply 8, between the sample 1 immersed in the electrolytic degreasing liquid accommodated in the said electrolytic degreasing treatment tank 3, and the electrode 7 which the electrolytic degreasing treatment tank 3 comprises A direct-current voltage can be applied, whereby an electrolytic degreasing treatment for confirming the cleanliness of the steel sheet surface can be easily performed. Similarly, a DC voltage can be applied between the sample 1 immersed in the electrolytic pickling solution accommodated in the electrolytic pickling treatment tank 5 and the electrode 7 included in the electrolytic pickling treatment tank 5. Thus, the electrolytic pickling treatment for confirming the cleanliness of the steel sheet surface can be easily performed.

清浄性確認装置2は、前記サンプルを前記電解脱脂液または電解酸洗液の液面に対して垂直に保持する手段と、保持したサンプルを水平方向に移動する手段と、保持したサンプルを昇降する手段を備えることが望ましい。これにより、何人が当該装置を使用しても、再現性よく鋼板表面の清浄性を確認することができる。
すなわち、本発明に係る鋼板表面の清浄性確認装置2によれば、たとえ使用する工業用水やリンガーロールの状態が不明であっても、焼鈍後表面処理前の段階において確実かつ容易に、液残り模様が発現するか否かを予測できるので、外観ならびに製品歩留まりに優れた電気めっき鋼板または化成処理鋼板を安定して製造することができる。
The cleanliness confirmation device 2 has means for holding the sample perpendicular to the surface of the electrolytic degreasing solution or electrolytic pickling solution, means for moving the held sample in a horizontal direction, and raising and lowering the held sample. It is desirable to provide means. Thereby, no matter how many people use the apparatus, the cleanliness of the steel sheet surface can be confirmed with good reproducibility.
That is, according to the cleanliness confirmation apparatus 2 for the steel sheet surface according to the present invention, even if the state of industrial water or ringer roll to be used is unknown, the liquid residue can be reliably and easily obtained at the stage before the surface treatment after annealing. Since it is possible to predict whether or not the pattern will appear, it is possible to stably produce an electroplated steel plate or a chemical conversion treated steel plate that is excellent in appearance and product yield.

したがって、当該清浄性確認装置は、図2に示すように、連続焼鈍ラインの出側に配置することが望ましい。これにより、表面処理鋼板の外観品質に最も重大な影響を与える鋼板表面の清浄性を事前に確認してから電気めっき等の表面処理を行うことができるので、めっき不良等を完全に防止することができる。
また、疑似模様が発現した場合には、表面処理作業を速やかに中止でき、従来技術では実施せざるを得なかった無駄な作業を防げるとともに、連続焼鈍ラインの前処理工程におけるリンス洗浄能力と液切り能力のいずれか一方または双方を強化する等の再発を防止するための対応を迅速に採ることができ、表面処理鋼板の外観品質ならびに製品歩留まりの改善を図ることができる。
なお、リンス洗浄能力の強化としては、リンス洗浄処理で使用する工業用水を増加させたり、リンス洗浄液の硫酸イオン濃度を10ppm以下に低下させる等の措置、リンス洗浄液の交換、リンス洗浄槽の増加、あるいは純水等のスプレー洗浄、ブラシ洗浄といった補助的洗浄を追加する等の措置をとることができる。
また、液切り能力の強化としては、リンガーロールの補修・交換、設置台数の増加、押付圧力の調整、あるいは吸液リンガーロールの追加等の措置をとることができる。
Therefore, as shown in FIG. 2, the cleanliness confirmation device is desirably arranged on the exit side of the continuous annealing line. As a result, it is possible to perform surface treatment such as electroplating after confirming the cleanliness of the steel plate surface that has the most significant impact on the appearance quality of the surface treated steel plate in advance, so that plating defects etc. can be completely prevented Can do.
In addition, when a pseudo pattern appears, the surface treatment operation can be stopped promptly, preventing unnecessary work that had to be performed by the conventional technology, and rinsing cleaning ability and liquid in the pretreatment process of the continuous annealing line. It is possible to quickly take measures to prevent a recurrence such as strengthening one or both of the cutting capabilities, and to improve the appearance quality and product yield of the surface-treated steel sheet.
In addition, as the strengthening of the rinse cleaning ability, measures such as increasing industrial water used in the rinse cleaning process or reducing the sulfate ion concentration of the rinse cleaning liquid to 10 ppm or less, replacement of the rinse cleaning liquid, increase in the rinse cleaning tank, Alternatively, it is possible to take measures such as adding auxiliary cleaning such as spray cleaning with pure water or brush cleaning.
In addition, for enhancing the liquid draining ability, it is possible to take measures such as repair and replacement of the ringer roll, increase in the number of installed units, adjustment of the pressing pressure, or addition of a liquid absorbing ringer roll.

一方、疑似模様が発現しない場合には、次工程である表面処理を安心して行うことができ、液残り模様の発現しない外観に優れた表面処理鋼板を安定して得ることができる。また、疑似模様が発現しないとの結果は、リンス洗浄処理工程における洗浄処理能力が正常であることを裏付けるものとなるから、熟練作業者の経験やノウハウに頼ることなく、経験の浅い作業者であっても適正な洗浄条件で操業することができ、操業の安定化ならびにリンス洗浄水のコスト削減を図ることができる。   On the other hand, when the pseudo pattern does not appear, the surface treatment as the next step can be performed with confidence, and a surface-treated steel sheet having an excellent appearance that does not exhibit the liquid residue pattern can be stably obtained. In addition, the result that the pseudo pattern does not appear confirms that the cleaning processing capability in the rinse cleaning process is normal, so that it is possible for an inexperienced worker to rely on the experience and know-how of a skilled worker. Even if it exists, it can be operated under appropriate cleaning conditions, and it is possible to stabilize the operation and reduce the cost of rinse water.

最後に、表面処理工程について説明するが、当該工程における表面処理は、焼鈍板に電気めっきと化成処理のいずれか一方または双方の表面処理を行うものであれば足り、一般的な電気Snめっきライン、電気亜鉛めっきライン、ティンフリースチールライン、りん酸処理ライン、およびクロメート処理ラインを用いることができるし、その表面処理条件も前記した液残り模様が発現しない硫酸イオン濃度の限界値調査において用いた条件等を実施できるものであれば足りる。   Finally, the surface treatment process will be described. The surface treatment in the process is sufficient if the annealing plate is subjected to either or both of electroplating and chemical conversion treatment, and a general electric Sn plating line. Electrogalvanization line, tin-free steel line, phosphate treatment line, and chromate treatment line can be used, and the surface treatment conditions were also used in the investigation of the limit value of sulfate ion concentration where the liquid residue pattern does not appear. It is sufficient if the conditions can be implemented.

(a)は不適正な条件で洗浄後、焼鈍・酸洗を行なって液残り模様が発現した場合の図であり、(b)は適正な条件で洗浄後、焼鈍・酸洗を行なって液残り模様が発現しなかった場合の図である。(A) is a figure in the case where a liquid residue pattern is developed by performing annealing / pickling after washing under improper conditions, and (b) is a liquid after washing under proper conditions, annealing / pickling. It is a figure when the remaining pattern does not express. 本発明に係る表面処理鋼板の製造方法の1態様を示すフローチャートである。It is a flowchart which shows 1 aspect of the manufacturing method of the surface treatment steel plate which concerns on this invention. 液残り模様が発現しない硫酸イオン濃度の限界値調査方法を示す模式図である。It is a schematic diagram which shows the limit value investigation method of the sulfate ion concentration which does not express a liquid residue pattern. 本発明に係る鋼板表面の清浄性確認装置の模式図である。It is a schematic diagram of the cleanliness confirmation apparatus of the steel plate surface concerning this invention.

符号の説明Explanation of symbols

1 サンプル 2 清浄性確認装置
3 電解脱脂処理槽 4 電解脱脂液を洗浄する水洗槽
5 電解酸洗処理槽 6 電解酸洗液を洗浄する水洗槽
7 電極 8 電源
9 サンプル側配線 10 処理槽側電極配線
DESCRIPTION OF SYMBOLS 1 Sample 2 Cleanliness confirmation apparatus 3 Electrolytic degreasing processing tank 4 Water washing tank which wash | cleans electrolytic degreasing liquid 5 Electrolytic pickling processing tank 6 Water washing tank 7 which wash | cleans electrolytic pickling liquid 8 Power supply 9 Sample side wiring 10 Processing tank side electrode wiring

Claims (14)

冷延鋼板にアルカリ洗浄と酸洗のいずれか一方または双方の洗浄処理と、前記洗浄処理で付着した洗浄液を鋼板表面から除去するリンス洗浄処理と、リンス洗浄処理で付着したリンス洗浄液を鋼板表面から除去する液切り処理とを行う連続焼鈍ラインの前処理工程と、
前処理された冷延鋼板を連続焼鈍する焼鈍工程と、
焼鈍された鋼板に電気めっきと化成処理のいずれか一方または双方の表面処理を行う表面処理工程
とを備えた表面処理鋼板の製造方法において、
前記焼鈍工程と表面処理工程の間に、
表面処理前の鋼板からサンプルを採取し、サンプルに電解脱脂処理と電解酸洗処理を順次行い、サンプル表面に所定の模様が発現するか否かにより鋼板表面の清浄性を評価する清浄性評価工程を更に備えたことを特徴とする外観に優れた表面処理鋼板の製造方法。
Either or both of alkaline cleaning and pickling on the cold rolled steel sheet, a rinse cleaning process for removing the cleaning liquid adhering to the cleaning process from the steel sheet surface, and a rinse cleaning liquid adhering to the cold cleaning steel sheet from the steel sheet surface A pre-treatment step of a continuous annealing line for performing liquid draining treatment to be removed;
An annealing process for continuously annealing the pre-treated cold-rolled steel sheet;
In the manufacturing method of the surface treatment steel plate provided with the surface treatment process which performs the surface treatment of either or both of electroplating and chemical conversion treatment to the annealed steel plate,
Between the annealing process and the surface treatment process,
A cleanliness evaluation process in which a sample is taken from the steel plate before the surface treatment, the sample is subjected to electrolytic degreasing treatment and electrolytic pickling treatment in order, and the cleanliness of the steel plate surface is evaluated by whether or not a predetermined pattern appears on the sample surface. A method for producing a surface-treated steel sheet having excellent appearance, further comprising:
前記清浄性評価工程において所定の模様が発現した場合には、連続焼鈍ラインの前処理工程におけるリンス洗浄能力と液切り能力のいずれか一方または双方を強化することを特徴とする請求項1に記載の外観に優れた表面処理鋼板の製造方法。
2. The method according to claim 1, wherein when a predetermined pattern is developed in the cleanliness evaluation step, either or both of the rinse cleaning ability and the liquid draining ability in the pretreatment step of the continuous annealing line are enhanced. For producing a surface-treated steel sheet having an excellent appearance.
前記リンス洗浄能力の強化が、硫酸イオン濃度が10ppm以下のリンス洗浄液を用いてリンス洗浄することを特徴とする請求項2に記載の外観に優れた表面処理鋼板の製造方法。
The method for producing a surface-treated steel sheet having excellent appearance according to claim 2, wherein the rinsing cleaning performance is enhanced by rinsing using a rinsing cleaning solution having a sulfate ion concentration of 10 ppm or less.
前記電解脱脂処理と電解酸洗処理を30〜240C/dmのクーロン量で行うことを特徴とする請求項1〜3のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
Method for producing a high surface-treated steel sheet appearance according to any one of claims 1 to 3, characterized in that the electrolytic degreasing and electrolytic pickling in coulombs of 30~240C / dm 2.
前記電解脱脂処理と電解酸洗処理を10〜35℃の温度で行うことを特徴とする請求項1〜4のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
The method for producing a surface-treated steel sheet having excellent appearance according to any one of claims 1 to 4, wherein the electrolytic degreasing treatment and the electrolytic pickling treatment are performed at a temperature of 10 to 35 ° C.
前記電解脱脂処理を、NaOH濃度が5〜50g/Lの電解脱脂液を用いて行うことを特徴とする請求項1〜5のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
The method for producing a surface-treated steel sheet having excellent appearance according to any one of claims 1 to 5, wherein the electrolytic degreasing treatment is performed using an electrolytic degreasing solution having a NaOH concentration of 5 to 50 g / L. .
前記電解酸洗処理を、HSO濃度が30〜50g/Lの電解酸洗液を用いて行うことを特徴とする請求項1〜5のいずれか1項に記載の外観に優れた表面処理鋼板の製造方法。
Wherein the electrolytic pickling process, excellent in appearance according to any one of claims 1 to 5, H 2 SO 4 concentration and performing using an electrolytic pickling solutions 30 to 50 g / L surface A method for producing a treated steel sheet.
電気めっき前または化成処理前の鋼板の表面清浄性を目視で確認するための装置であって、鋼板から採取したサンプルを電解脱脂する電解脱脂処理槽と、サンプルを電解酸洗する電解酸洗処理槽と、前記電解脱脂処理槽に収容された電解脱脂液または前記電解酸洗処理槽に収容された電解酸洗液に浸漬されたサンプルと各処理槽が各々具備する電極との間に直流電圧を印加する電源を備えたことを特徴とする鋼板表面の清浄性確認装置。
An apparatus for visually confirming the surface cleanliness of a steel plate before electroplating or chemical conversion treatment, an electrolytic degreasing bath for electrolytically degreasing a sample taken from the steel plate, and an electrolytic pickling treatment for electrolytically pickling the sample DC voltage between a bath, a sample immersed in an electrolytic degreasing solution contained in the electrolytic degreasing treatment bath or an electrolytic pickling solution contained in the electrolytic pickling treatment bath, and an electrode included in each treatment bath An apparatus for confirming the cleanliness of the surface of a steel sheet, comprising a power source for applying a pressure.
さらに、前記サンプルを前記電解脱脂液または電解酸洗液の液面に対して垂直に保持する手段と、保持したサンプルを水平方向に移動する手段と、保持したサンプルを昇降する手段を備えたことを特徴とする請求項8に記載の鋼板表面の清浄性確認装置。
Furthermore, a means for holding the sample perpendicular to the surface of the electrolytic degreasing solution or the electrolytic pickling solution, a means for moving the held sample in a horizontal direction, and a means for raising and lowering the held sample were provided. The cleanliness confirmation apparatus of the steel plate surface of Claim 8 characterized by these.
前記電解脱脂処理槽と電解酸洗処理槽における電解処理を30〜240C/dmのクーロン量で行うことを特徴とする請求項8または9に記載の鋼板表面の清浄性確認装置。
The electrolytic degreasing treatment vessel and purifier verification apparatus of the steel sheet surface according to electrolytic treatment in the electrolytic pickling bath in claim 8 or 9, characterized in that in coulombs of 30~240C / dm 2.
前記電解脱脂液と電解酸洗液の温度が10〜35℃であることを特徴とする請求項8〜10のいずれか1項に記載の鋼板表面の清浄性確認装置。
The temperature of the said electrolytic degreasing liquid and an electrolytic pickling liquid is 10-35 degreeC, The cleanliness confirmation apparatus of the steel plate surface of any one of Claims 8-10 characterized by the above-mentioned.
前記電解脱脂液のNaOH濃度が5〜50g/Lであることを特徴とする請求項8〜11のいずれか1項に記載の鋼板表面の清浄性確認装置。
The NaOH concentration of the said electrolytic degreasing liquid is 5-50 g / L, The cleanliness confirmation apparatus of the steel plate surface of any one of Claims 8-11 characterized by the above-mentioned.
前記電解酸洗液のHSO濃度が30〜50g/Lであることを特徴とする請求項8〜11のいずれか1項に記載の鋼板表面の清浄性確認装置。
Cleanliness checking apparatus of the steel sheet surface according to any one of claims 8 to 11 H 2 SO 4 concentration of the electrolyte pickling solution characterized in that it is a 30 to 50 g / L.
請求項8〜13のいずれか1項に記載の鋼板表面の清浄性確認装置を、連続焼鈍ラインの出側に配置したことを特徴とする外観に優れた表面処理鋼板の製造装置。
An apparatus for producing a surface-treated steel sheet excellent in appearance, wherein the apparatus for confirming the cleanliness of the steel sheet surface according to any one of claims 8 to 13 is arranged on the exit side of the continuous annealing line.
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