JPS621900A - Method for removing smut formed and stuck on surface of steel material containing ti - Google Patents

Abstract

PURPOSE:To remove smut stuck on a steel material contg. a specified amount of Ti stably and completely by anodizing the steel material in an aqueous permanganate soln. and immersing it in a dil. acid soln. after washing. CONSTITUTION:When a steel material contg. >=0.02wt% Ti is pickled, smut is formed and stuck on the surface of the steel material. This steel material having the stuck smut is anodized in an aqueous soln. of a strong oxidizing agent such as permanganate at about 5A/dm<2> current density for about several sec - 5min. The concn. of the aqueous soln. is about 100-300g/l. The steel material is then washed and immersed in a dil. acid soln. such as <=about 5% hydrochloric acid for about several sec - 2min. Thus, the smut on the steel material is removed and a clean activated steel surface is obtd.

Description

【発明の詳細な説明】 〈発明の目的〉 産業上の利用分野 本発明はＴｉ含有鋼材表面に生成付着したスマットの除
去方法に係り、詳しくは、酸洗処理時にＴｉ含有鋼材表
面に生成付着するスマットを除去でき、清浄な活性化さ
れた鋼表面を（ｑる方法に係る。[Detailed description of the invention] <Object of the invention> Industrial field of application The present invention relates to a method for removing smut formed and adhered to the surface of Ti-containing steel materials, and more specifically, to a method for removing smut formed and adhered to the surface of Ti-containing steel materials during pickling treatment. According to a method that can remove smut and create a clean activated steel surface.

従　　来　　の　　技　　術 熱処理後の鋼材表面にはスケールが生成され、これが熱
処理後に行なわれる圧延、伸線、めっき等の各種工程に
有害である。このため、これらの工程に先立ってスケー
ル除去、所謂、デスケールが行なわれている。このデス
ケール方法としては、塩酸、硫酸等の酸液で表面を洗浄
する酸洗処理が一般に用いられている。Conventional technology Scale is generated on the surface of steel materials after heat treatment, and this is harmful to various processes such as rolling, wire drawing, and plating that are performed after heat treatment. For this reason, scale removal, so-called descaling, is performed prior to these steps. As this descaling method, generally used is a pickling treatment in which the surface is cleaned with an acid solution such as hydrochloric acid or sulfuric acid.

ところが、Ｔｉ含有鋼材の場合、酸洗後の鋼材表面にス
マットが容易にかつ多口に生成付着してしまう場合が少
な（ない。このようなＴｉ含有鋼材のスマットについて
、元素分析（ＩＭＭＡによる）を行なった結果、Ｔｉお
よびＧがスマット中に；層化されていることが明らかに
なった。However, in the case of Ti-containing steel materials, it is rare that smut easily forms and adheres to the surface of the steel material after pickling. As a result, it was revealed that Ti and G were layered in the smut.

一般に、スマットは酸液と接触する全表面に一様に生成
付着し、生成直後の湿潤状態では、鋼材表面との密着力
が弱く、機械的な手段である程度除去可能であるが、乾
燥すると密着力が非常に強固となり、機械的な手段では
ほとんど除去不可能となる。このようなスマットが鋼材
表面に生成付着すると、鋼材の外観が劣下するばかりで
はなく、後工程で種々のトラブルの原因になる。In general, smut forms and adheres uniformly to all surfaces that come into contact with the acid solution, and when it is wet immediately after forming, it has weak adhesion to the steel surface and can be removed to some extent by mechanical means, but when it dries, it sticks tightly. The force becomes so strong that it is almost impossible to remove it by mechanical means. When such smut forms and adheres to the surface of a steel material, it not only deteriorates the appearance of the steel material, but also causes various troubles in subsequent processes.

例えば、圧延・伸線工程では表面疵の原因となり、めっ
き工程ではめっきの密着不良、外観不良の原因になって
いる。For example, it causes surface flaws in rolling and wire drawing processes, and causes poor plating adhesion and poor appearance in plating processes.

しかしながら、ステンレス鋼の如（、Ｃｒを含有する鋼
材ではスマットの種々の除去方法が開発されているが、
これらの除去方法を、Ｔｉ含有鋼の表面に生成付着した
スマットの除去に適用しても、このスマットの組成構造
がＣｒ含有鋼材のものと異なるため、スマットを短時間
に十分に除去することができない。However, various methods for removing smut have been developed for steel materials containing Cr, such as stainless steel.
Even if these removal methods are applied to remove smut generated and adhered to the surface of Ti-containing steel, it is difficult to remove smut sufficiently in a short time because the compositional structure of this smut is different from that of Cr-containing steel. Can not.

すなわち、Ｃｒを含有するステンレス鋼、低合金鋼等の
スマットについては、これまで種々の検討が加えられた
結果、この種の鋼に生成付着するスマットは、ＦｅとＯ
ｒとからなるスピネル型の複酸化物であることが明らか
となっており、上述したＴｉ含有鋼に生成付着するスマ
ットとは組成、構造に大きな差があると考えられる。従
来、このようなＣｒ含有鋼のスマッ［・の除去方法とし
てブラッシング、高圧水噴射等の物理的除去方法や、特
開昭５４−１１２７２９号に示す如く、過マンガン酸塩
の水溶液中への浸漬といった化学的除去方法が適用され
ている。しかしながら、これらの除去方法を、Ｔｉ含有
鋼の表面に生成付着したスマットの除去に適用しても、
何れの方法も、スマッ°トを短時間に十分に除去するこ
とができない。In other words, various studies have been conducted on smut in Cr-containing stainless steel, low alloy steel, etc., and it has been found that the smut that forms and adheres to these types of steel is composed of Fe and O.
It has been revealed that the smut is a spinel-type double oxide consisting of r and is thought to have a large difference in composition and structure from the smut that forms and adheres to the Ti-containing steel described above. Conventionally, methods for removing such smudge from Cr-containing steel include physical removal methods such as brushing and high-pressure water jetting, and immersion in an aqueous solution of permanganate as shown in JP-A-54-112729. Chemical removal methods such as However, even if these removal methods are applied to remove smut generated and adhered to the surface of Ti-containing steel,
None of the methods can sufficiently remove smut in a short time.

これは先に述べられたように、Ｔｉ含有鋼に生成付着す
るスマットとＣｒ含有鋼に生成付着するスマットの組成
、構造等に違いがあるためと考えられる。This is thought to be due to the difference in composition, structure, etc. of the smut that forms and adheres to Ti-containing steel and the smut that forms and adheres to Cr-containing steel, as described above.

発明が解決しようとする問題卓 本発明はこれらの事情を・３％まえ％Ｔｉ含有鋼表面の
スマットを簡単にかつ短時間の間に完全に除去し、清浄
な鋼表面を得ることを可能にするスマット除去方法を提
案することを目的とする。Problems to be Solved by the Invention The present invention solves these problems by easily and completely removing smut on the surface of a steel containing 3% Ti and making it possible to obtain a clean steel surface. The purpose of this study is to propose a method for removing smut.

〈発明の構成〉 問題点を解決するだめの手段 すなわち、本発明法は、酸洗時に、Ｔｉを０．０２重量
％以上含有する鋼材表面に生成付着するスマットを除去
する際に、前記鋼材を過マンガン酸塩等の強酸化剤の水
溶液中で陽極電解処理してから水洗し、その後、希薄酸
液中に浸漬することを特徴とする。<Structure of the Invention> A means for solving the problem, that is, the method of the present invention, is to remove smut generated and adhered to the surface of a steel material containing 0.02% by weight or more of Ti during pickling. It is characterized in that it is subjected to anodic electrolysis treatment in an aqueous solution of a strong oxidizing agent such as permanganate, then washed with water, and then immersed in a dilute acid solution.

まず、本発明方法においては、スマツ］・が生成付着し
たＴｉ含有鋼材を過マンガン酸塩の水溶液中で、陽極電
解処理後水洗し、希１酸液中に浸漬する。First, in the method of the present invention, a Ti-containing steel material on which smut has been formed and adhered is subjected to an anodic electrolysis treatment in an aqueous solution of permanganate, then washed with water, and then immersed in a dilute 1-acid solution.

この方法によれば、乾燥後の強固に付着したスマットで
あっても、常に安定して完全にこれを除去することがで
きる。According to this method, even if the smut is firmly adhered after drying, it can always be stably and completely removed.

そこで、これら手段たる構成ならびにその作用について
更に具体的に説明すると、次の通りである。Therefore, the structure of these means and their operation will be explained in more detail as follows.

すなわち、第１表に示す組成の供試鋼のスマット生成傾
向（２０％ＨＣ１水溶液中）を調べたところ、Ｔｉ含有
量とスマッ［・生成時間との間に５第１図に示すような
関係が得られた。That is, when we investigated the smut formation tendency (in a 20% HC1 aqueous solution) of the sample steels with the compositions shown in Table 1, we found that there was a relationship between the Ti content and the smut formation time as shown in Figure 1. was gotten.

第１表 第１図の結果から明らかな如く、スマットの生成付着が
特に顕著となるのが、Ｔｉ含有量が０．０２％以上であ
って、少なくとも０．０２％以上Ｔｉを含有する鋼につ
いてはスマットの除去対策が必要であることがわかった
。As is clear from the results in Table 1 and Figure 1, the formation and adhesion of smut is particularly noticeable when the Ti content is 0.02% or more, and for steels containing at least 0.02% Ti. It was found that measures to remove smut are necessary.

すなわち、スマットが生成付着したＴｉ含有鋼に対して
Ｃｒ含有鋼と同様にブラッシング、高圧水噴射等の物理
的除去方法を適用したところ、これらの物理的除去方法
ではスマットは一部除去できるものの鋼材表面の平滑度
に著しい影響をうけるなどのため、完全に除去すること
は不可能であった。In other words, when physical removal methods such as brushing and high-pressure water jetting were applied to Ti-containing steel on which smut had formed and adhered, in the same way as for Cr-containing steel, although these physical removal methods could partially remove smut, the steel It was impossible to completely remove it because it significantly affected the smoothness of the surface.

更に、過マンガン酸塩の水溶液中に浸漬して化学的除去
方法で除去したところ、スマッｉ・の一部は溶解された
り、除去可能なものに改質され、物理的除去方法に比べ
ると、スマント除去効果が大きかった。しかしながら、
このスマットの除去には、長時間の処理が必要であり、
その上、スマットが除去できても一部しか除去できず、
残存する場合が少なくない・ このところから、本発明法は、スマットが生成付着した
■１含有鋼を過マンガン酸塩等の強酸化剤の水溶液中で
陽極電解処理を行なう。このように処理すると、己れら
溶液の有する強力な酸化力と、陽極電解処理による陽極
酸化との相乗効果により、スマットの改質は飛躍的に促
進される。Furthermore, when it was removed by a chemical removal method by immersing it in an aqueous solution of permanganate, some of the smut was dissolved or modified into something that could be removed, and compared to physical removal methods, The effect of removing smant was great. however,
Removal of this smut requires a long process,
Moreover, even if smut can be removed, only a portion of it can be removed;
From this point of view, in the method of the present invention, 1-containing steel on which smut has formed is subjected to anodic electrolysis treatment in an aqueous solution of a strong oxidizing agent such as permanganate. When treated in this manner, the modification of smut is dramatically promoted due to the synergistic effect of the strong oxidizing power of the solution and the anodic oxidation caused by the anodic electrolytic treatment.

一方、陽極電解処理に伴ない、鋼材表面の不働態化も促
進されるため、処理後の鋼材表面には残留溶液、スマッ
トの改質物の他、部分的に不働態皮膜も形成される。こ
のため、水洗後、希Ｎ酸液中に浸漬する。この浸漬処理
によって、スマットの改質物等の他の不純物とともに容
易に除去され、清浄な活性化された鋼材表面が得られる
。On the other hand, since the anodic electrolytic treatment also promotes passivation of the surface of the steel material, a passive film is partially formed on the surface of the steel material after treatment, in addition to residual solution and modified smut. For this reason, after washing with water, it is immersed in a dilute N acid solution. By this dipping treatment, other impurities such as smut modifiers are easily removed, resulting in a clean activated steel surface.

なお、上記の如き強酸化剤の水溶液としては、強力な酸
化力を有するものであれば何れのものでも良いが、通常
は過マンガン酸塩の水溶液等が好適である。The aqueous solution of the above-mentioned strong oxidizing agent may be any solution as long as it has a strong oxidizing power, but an aqueous solution of permanganate or the like is usually suitable.

実施例 次に、実施例について説明する。Example Next, examples will be described.

まず、強酸化剤の水溶液として過マンガン酸塩の水溶液
を用い、塩酸酸洗中に０．２５％Ｔｉ１４表面に生成付
着したスマットの除去を行なったところ、第２図に示す
通りの結果が得られた。この場合、従来法で浸漬処理に
よって行なった場合をΔ印、本発明方法で陽極電解処理
した場合をＯ印（電流密度５Ａ／ｄｍ２）、・印（電流
密度１０Ａ／ｄＯ１２）で示す。First, using a permanganate aqueous solution as a strong oxidizing agent aqueous solution, we removed the smut that formed and adhered to the 0.25% Ti14 surface during hydrochloric acid pickling, and the results shown in Figure 2 were obtained. It was done. In this case, the case where the conventional immersion treatment was carried out is indicated by Δ, the case where the anodic electrolytic treatment was carried out by the method of the present invention is indicated by O (current density 5 A/dm2), and - (current density 10 A/dO12).

第２図から、従来法に比べると、本発明方法のスマット
除去時間は著しく短縮されていることがわかる。From FIG. 2, it can be seen that the smut removal time of the method of the present invention is significantly shorter than that of the conventional method.

また、この結果から、過マンガン酸塩の水溶液の濃度は
、スマットの除去能力とランニングコストから、１００
ａ／　１〜３０００ｚ″ｌが好適であることがわかる。Also, from this result, the concentration of permanganate aqueous solution is determined to be 100% from the smut removal ability and running cost.
It can be seen that a/1 to 3000z″l is suitable.

また、電解電流密度は５Ａ／ｃ１ｍ２あれば効果を発揮
し、　ＩＯＡ／ｄｉ２以上あれば十分であった。Further, an electrolytic current density of 5 A/c1m2 was effective, and an electrolytic current density of IOA/di2 or more was sufficient.

処理時間もこの結果かられかるように、数秒〜５分で通
常数１０秒までで十分であった。As can be seen from the results, the processing time was several seconds to 5 minutes, and usually up to several tens of seconds was sufficient.

〈発明の効果〉 以上詳しく説明した通り、本発明方法は、酸洗後の丁１
を０．０２％以上含有するＴｉ含有鋼材を強酸化剤の水
溶液に浸漬して陽極電解処理し、その後、希薄酸液中に
浸漬するものである。<Effects of the Invention> As explained in detail above, the method of the present invention provides
A Ti-containing steel material containing 0.02% or more of Ti is immersed in an aqueous solution of a strong oxidizing agent, subjected to anodic electrolysis treatment, and then immersed in a dilute acid solution.

従って、単に強酸化剤液中に浸漬するのみでなく、陽極
電解処理するため、鋼材表面のスマットを容易かつ完全
に除去し、清浄な鋼表面を得ることが可能であり、圧延
・伸線、めっき工程の前処理として広く適用できる。Therefore, it is not only immersed in a strong oxidizer solution, but also subjected to anodic electrolytic treatment, which makes it possible to easily and completely remove smut on the steel surface and obtain a clean steel surface. It can be widely applied as a pretreatment for plating processes.

また、希薄酸液としては塩酸を用いて、この液中にＴｉ
を０．２５％以下のものを浸漬し、しかも、Ｈｃｌ′ａ
度を変化させてスマット生成時間を求めたところ、第３
図に示す通りであった（第３図で○印はＴｉ　Ｏ，０１
％以下、Δ印はＴｉ　Ｏ，１％、◇印はＴｉ　Ｏ，２５
％）。この第３図において、斜線部は供試鋼である０、
２５％Ｔｉ！ｌでもスマットが生成しない範囲であり、
濃度は５％以下であった。In addition, hydrochloric acid was used as the dilute acid solution, and Ti
0.25% or less, and Hcl'a
When we calculated the smut generation time by varying the degree, we found that the third
As shown in the figure (in Figure 3, the ○ mark indicates TiO,01
% or less, Δ mark is TiO, 1%, ◇ mark is TiO, 25
%). In this Figure 3, the shaded area is the sample steel 0,
25% Ti! This is a range in which smut does not occur even at l,
The concentration was below 5%.

なお、希薄酸液としては、この塩酸の他、硫酸、硝酸等
の強酸で、浸漬処理中にスマットが生成しにくい１〜１
５％、通常、数％の濃度のものが好適であった。In addition to this hydrochloric acid, the dilute acid solution should be a strong acid such as sulfuric acid or nitric acid, which is 1 to 1 in which smut is difficult to form during the immersion process.
Concentrations of 5%, usually a few percent, were preferred.

処理時間は、数秒〜１〜２分で通常数１０秒までで十分
であり、過度の処理時間は、スマッ［・が再び生成、付
着するため、極力避けなければならなかった。The treatment time is from several seconds to 1 to 2 minutes, and usually up to several tens of seconds is sufficient; excessive treatment time must be avoided as much as possible because smear will regenerate and adhere.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はスマット生成時間とＴｉ含有量との関係を示す
グラフ、第２図は本発明法によるスマット除去効果を従
来法と比較して示すグラフ、第３図は塩酸濃度とスマッ
ト生成時間との関係を示すグラフである。Figure 1 is a graph showing the relationship between smut generation time and Ti content, Figure 2 is a graph showing the smut removal effect of the method of the present invention in comparison with the conventional method, and Figure 3 is a graph showing the relationship between hydrochloric acid concentration and smut generation time. It is a graph showing the relationship between.

Claims (1)

【特許請求の範囲】[Claims] 酸洗時に、Ｔｉを０．０２重量％以上含有する鋼材表面
に生成付着するスマットを除去する際に、前記鋼材を過
マンガン酸塩等の強酸化剤の水溶液中で陽極電解処理し
てから水洗し、その後、希薄酸液中に浸漬することを特
徴とするＴｉ含有鋼材表面に生成付着したスマットの除
去方法。When removing smut that forms and adheres to the surface of a steel material containing 0.02% by weight or more of Ti during pickling, the steel material is subjected to anodic electrolysis treatment in an aqueous solution of a strong oxidizing agent such as permanganate, and then washed with water. A method for removing smut generated and adhered to the surface of a Ti-containing steel material, the method comprising: and then immersing it in a dilute acid solution.