JPH0631475B2 - Manufacturing method of galvannealed steel sheet for cationic electrodeposition coating - Google Patents
Manufacturing method of galvannealed steel sheet for cationic electrodeposition coatingInfo
- Publication number
- JPH0631475B2 JPH0631475B2 JP62265953A JP26595387A JPH0631475B2 JP H0631475 B2 JPH0631475 B2 JP H0631475B2 JP 62265953 A JP62265953 A JP 62265953A JP 26595387 A JP26595387 A JP 26595387A JP H0631475 B2 JPH0631475 B2 JP H0631475B2
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- electrodeposition coating
- cationic electrodeposition
- galvannealed steel
- plating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Electroplating Methods And Accessories (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、カチオン電着塗装用ガルバニール鋼板の製
法、特に自動車車体を構成するカチオン電着塗装用ガル
バニール鋼板の製法に関する。Description: TECHNICAL FIELD The present invention relates to a method for producing a galvanic steel sheet for cationic electrodeposition coating, and particularly to a method for producing a galvanic steel sheet for cationic electrodeposition coating constituting an automobile body.
（従来の技術） 従来より、自動車車体の防錆性向上のため、塗膜性能の
よいカチオン電着塗料がプライマーとして採用されてい
る。また、近年では外面錆対策が求められ、車体外面に
も各種防錆鋼板が適用されてきている。しかし、カチオ
ン電着塗装時に急激に高電圧が表面に印加されるとクレ
ータと呼ばれる塗膜欠陥が発生することが多い。そこ
で、かかるクレータの発生を防止すべく上層に鉄濃度の
高いFe-Zn合金を電気めっきにより形成させる２層めっ
き鋼板が開発されている。例えば、特公昭58-15554号参
照。また、特開昭61-252397号において、ｐ含有量0.000
3〜15重量％のFe-p合金めっき層を上層に３ｇ／m2以上
施すことが提案されている。(Prior Art) Conventionally, a cationic electrodeposition coating having a good coating performance has been used as a primer in order to improve the rust prevention of an automobile body. Further, in recent years, measures against external rust have been demanded, and various anticorrosive steel sheets have been applied to the external surface of the vehicle body. However, when a high voltage is rapidly applied to the surface during cationic electrodeposition coating, coating film defects called craters often occur. Therefore, in order to prevent the occurrence of such craters, a two-layer plated steel sheet has been developed in which an Fe-Zn alloy having a high iron concentration is formed in the upper layer by electroplating. For example, see Japanese Examined Patent Publication No. 58-15554. Further, in JP-A-61-252397, the p content is 0.000.
It has been proposed to apply a Fe-p alloy plating layer of 3 to 15 wt% to the upper layer in an amount of 3 g / m 2 or more.
しかしながら、これらの方法をガルバニール鋼板に適用
した場合、クレータ防止には多大の目付量を要する。こ
れは表面粗度が大きいことによる。However, when these methods are applied to a galvannealed steel sheet, a large basis weight is required to prevent craters. This is because the surface roughness is large.
その他、かかるクレータ発生防止には、特開昭61-29195
7号には、表層を電解して表面から0.2〜0.3μｍの深さ
まで脱亜鉛を行って表層濃度を55〜92％とする方法が提
案されているが、厚膜化は避けられない。In addition, to prevent such craters, Japanese Patent Laid-Open No. 61-29195
No. 7 proposes a method in which the surface layer is electrolyzed and dezincification is performed from the surface to a depth of 0.2 to 0.3 μm to adjust the surface layer concentration to 55 to 92%, but thickening is inevitable.
したがって、少ない目付量にて表面を被覆しクレータ発
生防止および塗膜密着性に優れた化成被膜を析出させる
新規な上層めっき法の開発が望まれている。Therefore, there is a demand for the development of a new upper layer plating method for coating a surface with a small basis weight to prevent the formation of craters and deposit a chemical conversion coating excellent in coating adhesion.
（発明が解決しようとする問題点） かくして、本発明の目的は、少ない目付量にて表面を被
覆しクレータ発生防止および耐食性に優れた化成被膜が
析出する新規な上層めっき法を提供することである。(Problems to be solved by the invention) Thus, an object of the present invention is to provide a novel upper layer plating method for coating a surface with a small basis weight and depositing a chemical conversion film excellent in crater prevention and corrosion resistance. is there.
本発明者らは、かある目的を達成すべく種々検討を重ね
たところ、ガルバニール鋼板の製造工程において、溶融
亜鉛めっき層の合金化処理後、Fe-Zn合金の電気めっき
前に合金化溶融亜鉛めっき層の表面層を一部溶解させる
ことにより、少ない目付量にて表面を被覆しても、カチ
オン電着塗装性および耐食性に優れたガルバニール鋼板
を製造できることを見出し、本発明を完成した。The present inventors have made various studies to achieve a certain object, and in the manufacturing process of a galvannealed steel sheet, after the alloying treatment of the hot dip galvanized layer and before the electroplating of the Fe-Zn alloy, the hot dip galvannealed alloy is formed. By partially dissolving the surface layer of the plating layer, it has been found that a galvannealed steel sheet excellent in cationic electrodeposition coating property and corrosion resistance can be produced even if the surface is coated with a small basis weight, and the present invention has been completed.
（問題点を解決するための手段） ここに、本発明の要旨とするところは、合金化溶融亜鉛
めっき鋼板の少なくとも一方の表面層を一部溶解した
後、その上にFe60重量％以上含有するめっき層を電気め
っきにより施すことを特徴とするカチオン電着塗装用ガ
ルバニール鋼板の製法である。(Means for Solving Problems) Here, the gist of the present invention is that at least one surface layer of an alloyed hot-dip galvanized steel sheet is partially melted, and then 60 wt% or more of Fe is contained thereon. This is a method for producing a galvanic steel sheet for cationic electrodeposition coating, characterized in that the plating layer is applied by electroplating.
（作用） ここで、本発明にかかる方法は、その具体的構成を示せ
ば、（溶融亜鉛めっき）→（合金化）→（表面層の一部
溶解）→（Fe高濃度合金層の電気めっき）の各処理工程
から成る。ここに示す合金化溶融亜鉛めっき鋼板の製造
工程の（溶融亜鉛めっき）→（合金化）の各処理工程は
すでに当業者に周知であり、またそれにより得られた合
金化溶融亜鉛めっき鋼板もガルバニール鋼板としてよく
知られており、また、本発明にあってガルバニール鋼板
であればその製法は特に制限されないため、これ以上の
言及は省略する。(Operation) Here, in the method according to the present invention, if its specific configuration is shown, (hot dip galvanizing) → (alloying) → (partial dissolution of surface layer) → (electroplating of Fe high concentration alloy layer) ) Each processing step. The processing steps of (hot dip galvanizing) → (alloying) in the process for manufacturing the galvannealed steel sheet shown here are already well known to those skilled in the art, and the hot-dip galvanized steel sheet obtained thereby is also galvannealed. It is well known as a steel plate, and the manufacturing method thereof is not particularly limited as long as it is a galvannealed steel plate in the present invention, so further description will be omitted.
ガルバニール鋼板の表面層の一部溶解とは、ガルバニー
ル鋼板の製造時に形成される酸化膜のみの溶解でもよ
く、まためっき層を含んでもよい。しかし、めっき層の
溶解は少ない方が好ましい。表面層の溶解は、例えば塩
酸、硫酸などの酸液や苛性ソーダなどのアルカリ液に好
ましくは0.5〜５秒浸漬し、場合によっては電解条件下
で浸漬することによって行う。また、そのような溶解液
は電気めっき液に同じであってもよく、その場合には電
気めっきに先立って無通電状態であるいは陽極処理を行
いながらその電気めっき液に浸漬するだけでもよい。い
ずれにしても表面層の一部溶解という同じ作用効果が得
られるものであれば、特に制限はなく、いずれの方法に
よって表面層の一部溶解を行ってもよい。The partial dissolution of the surface layer of the galvannealed steel sheet may be only the dissolution of the oxide film formed at the time of manufacturing the galvannealed steel sheet, or may include the plating layer. However, it is preferable that dissolution of the plating layer is small. The surface layer is dissolved by, for example, immersing in an acid solution such as hydrochloric acid or sulfuric acid or an alkali solution such as caustic soda for preferably 0.5 to 5 seconds, and in some cases, immersing under electrolytic conditions. Further, such a solution may be the same as the electroplating solution, and in that case, it may be soaked in the electroplating solution prior to electroplating in a non-energized state or while performing anodization. In any case, there is no particular limitation as long as the same effect of partial dissolution of the surface layer can be obtained, and the partial dissolution of the surface layer may be performed by any method.
このような浸漬処理により合金化溶融亜鉛めっき層の表
面層の一部が溶解され、その上に施される電気めっきの
被覆率が著しく増大し、従来の認識に反して、極薄目付
量でも高いＰ値を得ることが出来るのである。ここに、
Ｐ値は、後述するホーパイトに対するホスホヒライト比
率を「％」で示す値であって、塗装後耐食性良否の指標
となるものであり、Ｐ値が大であれば塗装後耐食性は良
好となる。By such a dipping treatment, a part of the surface layer of the alloyed hot-dip galvanized layer is melted, and the coverage of electroplating applied on it is significantly increased. It is possible to obtain a high P value. here,
The P value is a value indicating the ratio of phosphohydrite with respect to hopite, which will be described later, in "%", and is an index of whether the corrosion resistance after coating is good or bad. If the P value is large, the corrosion resistance after coating becomes good.
次いで、Fe濃度60％以上のめっきを行う。代表例として
は、Fe-Zn合金電気めっきを行うが、その他、Fe濃度60
％以上が確保される限り、Fe-Mn、Fe-Ni、Fe-P、Fe-B系の
合金電気めっきを行ってもよい。このような合金電気め
っきそれ自体はすでに当業者に周知であって、本発明に
あっても特定の操業条件に制限されるものではない。Next, plating with an Fe concentration of 60% or more is performed. As a typical example, Fe-Zn alloy electroplating is performed.
%, Fe-Mn, Fe-Ni, Fe-P, or Fe-B alloy electroplating may be performed. Such alloy electroplating per se is well known to those skilled in the art, and the present invention is not limited to specific operating conditions.
このようにして得たカチオン電着塗装用鋼板は、一般に
はリン酸塩化成処理そしてカチオン電着塗装を行って自
動車車体用として使用される。このように引き続き行う
リン酸塩化成処理、そしてカチオン電着塗装についても
すでに公知の操作を繰り返せばよく、特定のものに制限
されるものではない。The steel sheet for cationic electrodeposition coating thus obtained is generally used for automobile bodies after being subjected to phosphate chemical conversion treatment and cationic electrodeposition coating. As for the subsequent phosphate chemical conversion treatment and the cationic electrodeposition coating, it is sufficient to repeat the already known operation, and the invention is not limited to a specific one.
次に、具体的例によって本発明の作用効果をさらに詳述
する。なお、本明細書において、「％」は特にことわり
がないかぎり、「重量％」である。Next, the action and effect of the present invention will be described in more detail with reference to specific examples. In the present specification, “%” is “% by weight” unless otherwise specified.
比較例 常法により製造したガルバニール鋼板に、表面層の溶解
を何ら行うことなく、従来法に従って、第１表に示す条
件にてFe-Zn合金めっきを施こし、化成処理性と耐クレ
ータ性を調査した。Comparative Example A galvannealed steel sheet produced by a conventional method was subjected to Fe-Zn alloy plating under the conditions shown in Table 1 according to the conventional method without melting the surface layer, to obtain chemical conversion treatment and crater resistance. investigated.
上層であるFe-Zn合金めっき層のFe％はめっき液中のFeS
O4・7H2O濃度で、目付量は通電時間によってそれぞれ調
整した。Fe% of the upper Fe-Zn alloy plating layer is FeS in the plating solution.
The O 4 · 7H 2 O concentration was used, and the basis weight was adjusted by the energization time.
次いで、通常に自動車用リン酸亜鉛処理を行い、Zn2Fe
(PO4)・4H2O（ホスホヒライト）とZn3(PO4)2・4H2O（ホー
パイト）とのＸ線回折強度比率でＰ値を求めて化成処理
性の指標とした。 Next, zinc phosphate treatment for automobiles is usually performed, and Zn 2 Fe is added.
The P value was determined by the X-ray diffraction intensity ratio of (PO 4 ) .4H 2 O (phosphohydrite) and Zn 3 (PO 4 ) 2 / 4H 2 O (hopite) to be used as an index of chemical conversion treatability.
耐クレータ性は、慣用の自動車用カチオン電着塗料を用
いて300Ｖ×２分の条件で通常の電着塗装を行い、焼付
後の表面欠陥の発生状況で評価した。The crater resistance was evaluated by performing ordinary electrodeposition coating under a condition of 300 V × 2 minutes using a conventional automobile cationic electrodeposition coating and evaluating the occurrence of surface defects after baking.
第１図にはＰ値で示す化成処理性を上層めっきの目付量
に対しグラフで示す。Fe-Zn合金めっきのFe％のＰ値に
対する影響は小さく、目付量の影響が大きい。目付量が
１ｇ／m2ではＰ値はゼロで、目付量７ｇ／m2でもＰ値は
80％以下と低い。FIG. 1 is a graph showing the chemical conversion treatability represented by the P value against the basis weight of the upper layer plating. The Fe% of Fe-Zn alloy plating has a small influence on the P value, and the influence of the basis weight is large. When the basis weight is 1 g / m 2 , the P value is zero. Even when the basis weight is 7 g / m 2 , the P value is
It is as low as 80% or less.
また耐クレータ性は第２表にまとめて示すように、若干
Ｐ値とは異なる傾向であるが、高Fe％で厚目付量でない
とクレータが発生することが分かる。Also, as shown in Table 2 collectively, the crater resistance tends to be slightly different from the P value, but it can be seen that craters occur unless the Fe content is high and the weight is not large.
以上から、従来法によれば、薄目付量にては化成処理性
および耐クレータ性を改善することができないことが分
かる。 From the above, it is understood that according to the conventional method, the chemical conversion treatment property and the crater resistance cannot be improved with a light weight.
実施例１ 室温の10%塩酸浴に慣用のアルバニール鋼板を浸漬して
表面層を一部溶解して、第１表と同一条件で80％Fe-Zn
合金めっきを３ｇ／m2施し、前述の比較例の手順にした
がって、Ｐ値と耐クレータ性を評価した。結果を第２図
にグラフにまとめて示す。Example 1 A conventional Albanyl steel sheet was immersed in a 10% hydrochloric acid bath at room temperature to partially dissolve the surface layer, and 80% Fe-Zn was formed under the same conditions as in Table 1.
Alloy plating was applied at 3 g / m 2 , and the P value and crater resistance were evaluated according to the procedure of the comparative example described above. The results are summarized in the graph in FIG.
第２図に示す結果からも分かるように、本発明によれ
ば、上記塩酸浴に0.5秒浸漬するだけで上層めっきの目
付量３ｇ／m2でＰ値が１００％となり、しかもクレータ
の発生がみられなくなる。As can be seen from the results shown in FIG. 2, according to the present invention, the P value becomes 100% when the weight per unit area of the upper layer plating is 3 g / m 2 and the crater is generated only by immersing in the hydrochloric acid bath for 0.5 seconds. It will not be seen.
かかる効果は、塩酸浸漬のみならず、陽極電解でも同じ
であり、また硫酸など他の酸を用いても同様の効果が発
揮される。電気めっきに先立って電気を通ぜずに、めっ
き液によって表面溶解を行っても同様の効果が見られ
た。This effect is the same not only in hydrochloric acid immersion, but also in anodic electrolysis, and the same effect is exhibited by using other acids such as sulfuric acid. The same effect was observed even if the surface was dissolved by a plating solution without passing electricity prior to electroplating.
さらに、苛性ソーダのようなアルカリ液を用いても同様
の効果が得られる。Further, the same effect can be obtained by using an alkaline solution such as caustic soda.
Fe-Zn合金めっき前の表面溶解が塗装後耐食性ならびに
耐クレータ性向上に寄与する機構については明確ではな
いが、以下のごとく推定される。ガルバニール鋼板の製
造時に表面に形成されるAl、Znを含む酸化膜は電気抵抗
が高く電気めっき時にめっきされにくく、めっき層の不
均一化をもたらすためその解消には大きな目付量が必要
となる。従って、めっき前にそのような表面層を溶解す
ることにより電気めっきが均一に行われ表面被覆率が上
がるため特性が向上すると考えられる。あるいは、ガル
バニール鋼板の表面からの亜鉛の優先溶解により部分的
に表面層のFe濃度が高くなる部分ができ、薄目付量でも
Fe-Znめっきの表面被覆率を上げることとなり塗装後耐
食性と耐クレータ性が向上するとも考えられる。The mechanism by which surface dissolution before Fe-Zn alloy plating contributes to the improvement of corrosion resistance and crater resistance after painting is not clear, but it is presumed as follows. The oxide film containing Al and Zn formed on the surface of a galvannealed steel sheet has a high electric resistance and is hard to be plated during electroplating, which causes nonuniformity of the plating layer, and therefore a large basis weight is required to eliminate it. Therefore, it is considered that by dissolving such a surface layer before plating, electroplating is uniformly performed and the surface coverage is increased, so that the characteristics are improved. Alternatively, the preferential dissolution of zinc from the surface of the galvannealed steel sheet creates a part where the Fe concentration in the surface layer becomes high, and even with a light weight.
It is considered that the corrosion resistance and crater resistance after coating will be improved by increasing the surface coverage of Fe-Zn plating.
実施例２ 慣用のガルバニール鋼板を50℃の５％硫酸浴に１秒間浸
漬したのち、各種めっき条件にてFe-Zn電気めっきを施
し、次いで慣用の自動車用リン酸亜鉛処理を行ってから
同じく慣用の自動車用カチオン電着塗装処理を行い、耐
クレータ性および化成処理性を評価した。Example 2 A conventional galvannealed steel plate was immersed in a 5% sulfuric acid bath at 50 ° C. for 1 second, Fe-Zn electroplated under various plating conditions, and then subjected to a conventional automobile zinc phosphate treatment, and then similarly used. Was subjected to a cationic electrodeposition coating treatment for automobiles, and its crater resistance and chemical conversion treatment performance were evaluated.
結果を第３表にまとめて示す。本発明にかかる方法によ
れば、0.5ｇ／m2以上の薄目付量にて良好な塗装性が得
られることは明らかである。The results are summarized in Table 3. According to the method of the present invention, it is apparent that good coatability can be obtained with a weight per unit area of 0.5 g / m 2 or more.
以上のように、本発明によりガルバニール鋼板の表面を
わずかに溶解したのち60％以上とFe濃度の高いFe-Zn合
金めっきを0.5ｇ／m2以上施すことにより良好な耐クレ
ータ性および化成性を有するようになる。 As described above, according to the present invention, the surface of a galvannealed steel sheet is slightly melted, and then Fe-Zn alloy plating having a high Fe concentration of 60% or more is applied to 0.5 g / m 2 or more to obtain good crater resistance and chemical conversion. To have.
（発明の効果） 以上説明したように、本発明によれば、合金電気めっき
に先立って単に表面層を溶解するという簡便な操作でも
って、従来問題であって厚目付を避けて薄目付でもって
十分に耐クレータ性および化成処理性を確保できるので
あり、実用上の観点からその意義は大きい。(Effects of the Invention) As described above, according to the present invention, a simple operation of simply melting the surface layer prior to alloy electroplating can be performed, and a conventional method, which is a problem of avoiding a thick weight and a light weight, can be used. It is possible to secure sufficient crater resistance and chemical conversion treatability, which is of great significance from a practical point of view.
第１図は、比較例におけるＰ値で示す化成処理性のグラ
フ；および 第２図は、本発明におけるクレータの発生およびＰ値を
浸漬時間に対して示すグラフである。FIG. 1 is a graph of chemical conversion treatability shown by P value in Comparative Example; and FIG. 2 is a graph showing occurrence of craters and P value in the present invention with respect to immersion time.
Claims (1)
方の表面層を一部溶解した後、その上にFe60重量％以上
含有するめっき層を電気めっきにより施すことを特徴と
するカチオン電着塗装用ガルバニール鋼板の製法。1. A cationic electrodeposition coating, characterized in that at least one surface layer of a galvannealed steel sheet is partially melted, and then a plating layer containing 60 wt% or more of Fe is applied by electroplating. Galvanile steel sheet manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62265953A JPH0631475B2 (en) | 1987-10-21 | 1987-10-21 | Manufacturing method of galvannealed steel sheet for cationic electrodeposition coating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62265953A JPH0631475B2 (en) | 1987-10-21 | 1987-10-21 | Manufacturing method of galvannealed steel sheet for cationic electrodeposition coating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01108396A JPH01108396A (en) | 1989-04-25 |
| JPH0631475B2 true JPH0631475B2 (en) | 1994-04-27 |
Family
ID=17424357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62265953A Expired - Lifetime JPH0631475B2 (en) | 1987-10-21 | 1987-10-21 | Manufacturing method of galvannealed steel sheet for cationic electrodeposition coating |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0631475B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2702217B2 (en) * | 1989-03-16 | 1998-01-21 | 川崎製鉄株式会社 | Method for producing galvannealed steel sheet having powdering resistance |
| US5236574A (en) * | 1989-05-08 | 1993-08-17 | Sumitomo Metal Industries, Ltd. | Electroplating of hot-galvanized steel sheet and continuous plating line therefor |
| JP2619542B2 (en) * | 1989-12-01 | 1997-06-11 | 川崎製鉄株式会社 | Method for producing hot-dip zinc-based two-layer plated steel sheet excellent in uniformity of upper iron-based electroplating |
| JP2541380B2 (en) * | 1991-01-14 | 1996-10-09 | 日本鋼管株式会社 | Method for producing iron-zinc alloy-plated steel sheet having a plurality of iron-zinc alloy plating layers having excellent electrodeposition coatability |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57114695A (en) * | 1980-12-01 | 1982-07-16 | Nisshin Steel Co Ltd | Production of zinc plated steeel plate of superior blackening resistance and intergranular corrosion resistance |
| JPS5815554A (en) * | 1981-07-21 | 1983-01-28 | Toray Ind Inc | Resin composition |
| US4510209A (en) * | 1980-09-12 | 1985-04-09 | Nippon Steel Corporation | Two layer-coated steel materials and process for producing the same |
-
1987
- 1987-10-21 JP JP62265953A patent/JPH0631475B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4510209A (en) * | 1980-09-12 | 1985-04-09 | Nippon Steel Corporation | Two layer-coated steel materials and process for producing the same |
| JPS57114695A (en) * | 1980-12-01 | 1982-07-16 | Nisshin Steel Co Ltd | Production of zinc plated steeel plate of superior blackening resistance and intergranular corrosion resistance |
| JPS5815554A (en) * | 1981-07-21 | 1983-01-28 | Toray Ind Inc | Resin composition |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01108396A (en) | 1989-04-25 |
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