JPH03173795A - Production of double layer plated steel sheet having superior covering property of upper iron-based electroplating and superior powdering resistance - Google Patents
Production of double layer plated steel sheet having superior covering property of upper iron-based electroplating and superior powdering resistanceInfo
- Publication number
- JPH03173795A JPH03173795A JP31278589A JP31278589A JPH03173795A JP H03173795 A JPH03173795 A JP H03173795A JP 31278589 A JP31278589 A JP 31278589A JP 31278589 A JP31278589 A JP 31278589A JP H03173795 A JPH03173795 A JP H03173795A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- plating
- iron
- superior
- plated steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000009713 electroplating Methods 0.000 title claims abstract description 29
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 25
- 239000010959 steel Substances 0.000 title claims abstract description 25
- 238000000227 grinding Methods 0.000 title claims abstract description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 58
- 229910052742 iron Inorganic materials 0.000 title claims description 27
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 6
- 238000011282 treatment Methods 0.000 claims description 17
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 12
- 239000008397 galvanized steel Substances 0.000 claims description 12
- 238000005246 galvanizing Methods 0.000 claims description 9
- 239000012670 alkaline solution Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 6
- 238000007747 plating Methods 0.000 abstract description 38
- 239000003513 alkali Substances 0.000 abstract description 3
- 239000011701 zinc Substances 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000000126 substance Substances 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004070 electrodeposition Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004453 electron probe microanalysis Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000004452 microanalysis Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、下層に溶融亜鉛系めっき合金化溶融亜鉛めっ
き、上層に鉄系電気めっきを施した２層めっき鋼板の製
造方法に関し、特にその上層鉄系めっきの均一電着性が
著しく改善され、かつ耐パウダリング性に優れた２層め
っき鋼板の製造方法を提供するものである。[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing a two-layer plated steel sheet in which the lower layer is coated with hot-dip galvanized alloyed galvanized steel and the upper layer is coated with iron-based electroplating. The present invention provides a method for producing a two-layer plated steel sheet in which the uniform electrodeposition of the upper layer iron-based plating is significantly improved and the powdering resistance is excellent.
〈従来の技術〉
合金化溶融亜鉛めっき鋼板は、その優れた耐食性から、
自動車外板をはじめとしてその用途が広く拡大しつつあ
る。 しかしこのようなめっき鋼板上に電看塗装を施す
と、クレータ等の欠陥が発生する為、合金化溶融亜鉛め
フき層の上にさらに鉄系のめっきを施すことが行われて
いる。<Conventional technology> Alloyed hot-dip galvanized steel sheets are known for their excellent corrosion resistance.
Its applications are expanding widely, including automobile exterior panels. However, when electrical coating is applied to such a plated steel sheet, defects such as craters occur, so iron-based plating is further applied on top of the alloyed hot-dip galvanized layer.
例えば、特開昭５５−１３３４８８号公報には下層めっ
きとして亜鉛系めっきを施した上にＦｅ、−Ｚｎ系上層
めっきを施すこと、特公平０１−１６９１９号公報には
下層めっきとして亜鉛系めっきを施した上にＦｅ−Ｐ系
上層めフきを施すことが、また特開昭８１−２５３３９
７号公報では下層めっきとして合金化溶融亜鉛めっぎを
施した上にＦｅ−Ｐ系上層めっきを施すことによって、
下層めっきで耐食性を持たせ、上層めっきで化成処理性
や耐クレータ性を改善する発明が開示されている。For example, JP-A-55-133488 discloses that zinc-based plating is applied as the lower layer plating and then Fe, -Zn-based upper layer plating is applied, and JP-A-01-16919 discloses that zinc-based plating is applied as the lower layer plating. It is also possible to apply an Fe-P-based upper layer wiper on top of the
In Publication No. 7, by applying alloyed hot-dip galvanizing as the lower layer plating and then applying Fe-P based upper layer plating,
An invention has been disclosed in which corrosion resistance is provided by lower layer plating, and chemical conversion treatment property and crater resistance are improved by upper layer plating.
〈発明が解決しようとする課題〉
これらの技術では、下層めっきが電気めっきの場合は所
期した性能の２層めっき鋼板が安定して得られるが、下
層めっきが合金化溶融亜鉛めっきの場合には、必ずしも
常に十分な性能の２層めっき鋼板が得られない問題があ
った。<Problem to be solved by the invention> With these techniques, when the lower layer plating is electroplating, a two-layer plated steel sheet with the desired performance can be stably obtained, but when the lower layer plating is alloyed hot-dip galvanizing, However, there was a problem in that it was not always possible to obtain a two-layer plated steel sheet with sufficient performance.
また、最近、合金化溶融亜鉛めっき鋼板を、前述した自
動車外板などの複雑なプレス加工を受ける用途にも広く
使用するに及んで、プレス加工時にめっき層が剥離する
いわゆるパウダリングが問題となフた。 これを解決す
るために、溶融亜鉛めっき後の合金化を低目とし、合金
化溶融亜鉛めっ幹層の平均Ｆｅ含有率を従来の１０〜１
３１ｉ量％から７〜１０重量％に低減する対策が採られ
るようになったが、その結果、前述の上層めっきを施し
た場合に、上層鉄系電気めっきのカバリングが不均一な
ために耐クレータ性や化成処理性が一層著しく不安定と
なる問題が新たに発生してきた。In addition, recently, alloyed hot-dip galvanized steel sheets have been widely used in applications that undergo complex press forming, such as the above-mentioned automobile exterior panels, and so-called powdering, in which the plating layer peels off during press forming, has become a problem. Futa. In order to solve this problem, the alloying after hot-dip galvanizing was lowered, and the average Fe content of the alloyed hot-dip galvanized base layer was reduced from 10 to 1
Measures have been taken to reduce the amount of 31i from 7 to 10% by weight, but as a result, when the above-mentioned upper layer plating is applied, the covering of the upper layer iron-based electroplating is uneven, making it difficult to resist cratering. A new problem has arisen in which properties and chemical conversion properties become even more unstable.
これに対し、応急的な対策として、鉄系電気めっきの付
着量を増加させることにより化成処理性は改良されうる
けれども、耐食性が劣化するために実用的ではなかった
。On the other hand, as a temporary measure, chemical conversion treatment properties could be improved by increasing the amount of iron-based electroplating, but this was not practical because the corrosion resistance deteriorated.
本発明は、前述した合金化溶融亜鉛めっき鋼板、とりわ
け低Ｆｅ含有率の合金化処理を施された合金化溶融亜鉛
めっき鋼板に鉄系上層めっきを施して２層めっき鋼板と
する際の上層鉄系電気めっきのカバリングが不均一なた
めに耐クレータ性や化成処理性が著しく不安定となる問
題を有利に解決する、上層鉄系電気めっきのカバリング
に優れ、かつ耐バツクリング性に優れた２層めっき鋼板
の製造方法を提供することを目的とする。The present invention relates to the above-mentioned alloyed hot-dip galvanized steel sheet, particularly the upper layer iron when an iron-based upper layer plating is applied to the alloyed hot-dip galvanized steel sheet that has been subjected to alloying treatment with a low Fe content to produce a two-layer plated steel sheet. Two layers with excellent coverage of the upper layer iron-based electroplating and excellent backling resistance, which advantageously solves the problem of extremely unstable crater resistance and chemical conversion treatment properties due to uneven coverage of the electroplating system. The purpose of this invention is to provide a method for manufacturing plated steel sheets.
く課題を解決するための手段〉
本発明者らは、溶融亜鉛系めっきや合金化溶融亜鉛めっ
き上に鉄系めっきを施した場合に上層鉄系電気めっきの
カバリング不良により耐クレータ性や化成処理性が著し
く不安定となる現象が何故発生するかについて詳細に検
討を重ねた結果、合金化溶融亜鉛めっ、き層の表面は加
熱合金化工程を経るうちに著しく不活性な状態になるた
め、鉄系めっきの電着反応を著しく不均一化しているこ
とをつぎとめ々。Means for Solving the Problems> The present inventors have discovered that when iron-based plating is applied on top of hot-dip galvanizing or alloyed hot-dip galvanizing, poor coverage of the upper iron-based electroplating results in poor crater resistance and chemical conversion treatment. As a result of detailed investigation into why the phenomenon of extremely unstable properties occurs, we found that the surface of the alloyed hot-dip galvanized layer becomes extremely inactive during the heating alloying process. It has been repeatedly noticed that the electrodeposition reaction of iron-based plating becomes significantly non-uniform.
このような不活性な表面状態を活性たらしめる方法とし
て種々考えられるが、一般的な電気めっきラインで採用
されている塩酸や硫酸を使用した酸洗による活性化では
合金化溶融亜鉛めっきが著しく溶解してしまうために効
果が認められないうえにパウダリングが著しく劣化して
しまう、 それに対し、鉄系電気めっきを施す前に合金
化溶融亜鉛めつき鋼板表面を弱アルカリ液中で陰極電解
処理することが、鉄系上層めっきを均一に電着せしめる
うえで特に有効な事を発見し、本発明に至ったものであ
る。Various methods can be considered to activate such an inactive surface state, but the activation by pickling using hydrochloric acid or sulfuric acid, which is used in general electroplating lines, significantly dissolves the alloyed hot-dip galvanizing. However, before iron-based electroplating, the surface of the alloyed hot-dip galvanized steel sheet is subjected to cathodic electrolysis treatment in a weak alkaline solution. It was discovered that this is particularly effective for uniformly electrodepositing the iron-based upper layer plating, leading to the present invention.
すなわち、本発明は、合金化溶融亜鉛めっき上に鉄系電
気めワきを施す２層めっき鋼板の製造方法において、鉄
系電気めっきを施す前に合金化溶融亜鉛めっき鋼板表面
を弱アルカリ液中で陰極電解処理した後に鉄系電気めっ
きを施すことを特徴とする、上層鉄系電気めっきのカバ
リングに優れ、かつ耐バツクリング性に優れた２層めっ
き鋼板の製造方法を提供する。That is, the present invention provides a method for producing a two-layer plated steel sheet in which iron-based electroplating is applied on alloyed hot-dip galvanizing, in which the surface of the alloyed hot-dip galvanized steel sheet is placed in a weak alkaline solution before applying iron-based electroplating. To provide a method for producing a two-layer plated steel sheet having excellent covering of an upper layer of iron-based electroplating and excellent buckling resistance, characterized in that iron-based electroplating is applied after cathodic electrolytic treatment.
また、前記弱アルカリ液のｐＨは８〜１２であるのがよ
い。Further, the pH of the weak alkaline solution is preferably 8 to 12.
以下に本発明を更に詳細に説明する。The present invention will be explained in more detail below.
本発明に使用する鋼板としては、特に限定しないが、例
えば一般の冷延鋼板、熱延鋼板、高張力鋼板などが使用
できる。Although the steel plate used in the present invention is not particularly limited, for example, general cold-rolled steel plates, hot-rolled steel plates, high-strength steel plates, and the like can be used.
本発明が対象とする下層めっきは、合金化溶融亜鉛めっ
きである。 これは鋼板に溶融亜鉛めっきを施し直ちに
加熱処理して下地鋼板からめっき層中へＦｅを拡散合金
化せしめた鋼板である。 ここで、溶融亜鉛浴組成、そ
のめっき条件ならびに合金化条件などは一般に行なわれ
ている方法に従えばよい。The lower layer plating targeted by the present invention is alloyed hot-dip galvanizing. This is a steel sheet in which a steel sheet is hot-dip galvanized and immediately heat-treated to diffuse and alloy Fe from the base steel sheet into the plating layer. Here, the composition of the molten zinc bath, its plating conditions, alloying conditions, etc. may be determined according to commonly used methods.
本発明においては上述したような合金化溶融亜鉛めフき
鋼板表面を弱アルカリ液中で陰極電解処理する。 その
際、使用する弱アルカリ液は特に限定しないが、水酸化
ナトリウム、水酸化カリウム、水酸化アンモニウム、水
酸化カルシウム等の希釈溶液、あるいはこれらの炭酸塩
などが好適に使用でき、そのｐＨの範囲は８〜１２が好
ましい。In the present invention, the surface of the alloyed hot-dip galvanized steel sheet as described above is subjected to cathodic electrolysis treatment in a weak alkaline solution. At this time, the weak alkaline solution to be used is not particularly limited, but dilute solutions of sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, etc., or carbonates of these can be suitably used, and the pH range is preferably 8 to 12.
また、処理にあたっては、これらの液中で陰極電解処理
を行うことが必須である。Furthermore, during the treatment, it is essential to perform cathodic electrolysis treatment in these solutions.
すなわち、上記のｐＨよりも高ｐＨ領域で処理したり、
陽極電解処理または無電解浸漬処理でも合金化溶融亜鉛
めっき層表面の活性化は可能であるが、その場合、合金
化溶融亜鉛めっき層のエツチングが必然的に生じ、めっ
き層が剥離し易い状態となるためプレス成形時にパウダ
リングが発生し易くなる。That is, processing in a higher pH range than the above pH,
Although it is possible to activate the surface of the alloyed hot-dip galvanized layer by anodic electrolytic treatment or electroless immersion treatment, in that case, etching of the alloyed hot-dip galvanized layer inevitably occurs, resulting in a state in which the plated layer is likely to peel off. Therefore, powdering is likely to occur during press molding.
また、上記のｐＨよりも低ｐＨ領域で処理すると十分な
活性化作用が得られずしたがって上層鉄系めっきの均一
電着が望めないうえ、処理時に合金化溶融亜鉛めつぎ層
のエツチングが必然的に生じ、めっ、き層が剥離し易い
状態となるためプレス成形時にパウダリングが発生し易
くなる。Furthermore, if the treatment is performed at a pH lower than the above pH, a sufficient activation effect will not be obtained, and uniform electrodeposition of the upper iron-based plating cannot be expected, and etching of the alloyed hot-dip galvanized layer will inevitably occur during treatment. This causes the plating layer to easily peel off, making it easier for powdering to occur during press molding.
このようにして得られた弱アルカリ液中で陰極電解処理
した合金化溶融亜鉛めっき鋼板の上層に施す鉄系めっぎ
としては、Ｆｅ−Ｚｎ系電気めっぎ、Ｆａ−Ｐ系電気め
っきが好適で、その組成、めっき条件は公知の範囲が適
用できる。As the iron-based plating applied to the upper layer of the alloyed hot-dip galvanized steel sheet that has been cathodically electrolyzed in the weakly alkaline solution obtained in this way, Fe-Zn-based electroplating and Fa-P-based electroplating are used. Suitable compositions and plating conditions can be applied within known ranges.
〈実施例〉 以下に本発明を実施例に基づいて具体的に説明する。<Example> The present invention will be specifically described below based on Examples.
（実施例１）
合金化溶融亜鉛めっき鋼板（目付量４５ｇ ／ ｍ ”
平均鉄含有率９．５重量％、以下Ｇ＾と略す）に予
備処理として各種アルカリ溶液処理、酸処理または無処
理で、その上にＦｅ−Ｐ電気めフぎまたはＦｅ−Ｚｎ電
気めっきを施し、上層めっきの均一性ならびにパウダリ
ング性を調査した。(Example 1) Alloyed hot-dip galvanized steel sheet (fabric weight 45 g / m ”
(average iron content 9.5% by weight, hereinafter abbreviated as G^) was pretreated with various alkali solution treatments, acid treatment, or no treatment, and then Fe-P electroplating or Fe-Zn electroplating was applied thereto. The uniformity and powdering properties of the upper layer plating were investigated.
得られた結果を表１に示す。The results obtained are shown in Table 1.
上層電気めっき条件
（１）硫酸浴Ｆｅ−Ｐ電気めっき条件
ＦｅＳＯ４・７Ｈ２０２５０ｇ／ｌ
Ｎａ２ＳＯ４１００ｇ／Ｉ
ＮａＨｘ ＰＯ２・Ｈ２００，２ｇ／１（２）塩化浴Ｆ
ｅ−Ｐ電気めっき条件
ＦｅＣｌ２ ・４Ｈ２０２４０ｇ／ｌ
ＫＣｌ １８０ｇ／ＩＮａＨａ Ｐ
ｏ２・Ｈ２００，２ｇ／１（３）硫酸浴Ｆｅ−Ｚｎ電気
めっき条件Ｆ ｅ Ｓ Ｏａ ・７ Ｈ２０３０ｏｇ
／１ＺｎＳＯａ ・７Ｈ２０１７ｇ／ｌ
Ｎ１１２Ｓ（１４５０ｇ／ｌ
なお、各評価項目の評価方法を以下に記す。Upper layer electroplating conditions (1) Sulfuric acid bath Fe-P electroplating conditions FeSO4・7H20250g/l Na2SO4100g/I NaHx PO2・H200,2g/1 (2) Chloride bath F
e-P electroplating conditions FeCl2 ・4H20240g/l KCl 180g/INaHa P
o2・H200, 2g/1(3) Sulfuric acid bath Fe-Zn electroplating conditions F e S Oa ・7 H2030og
/1ZnSOa 7H2017g/l N112S (1450g/l The evaluation method for each evaluation item is described below.
■上層めっきの均一性： ＥＰＭＡのマイクロアナリシス結果によって評価した。■Uniformity of upper layer plating: Evaluation was made based on EPMA microanalysis results.
Ｏ：下層Ｚｎのピークの認められないもの
Δ：下層Ｚｎのピークが一部に認めらるもの
Ｘ：下層Ｚｎのピークが全面に認められるもの
■パウダリング性：
鉄系電気めっきを施した鋼板を９０”曲げ−曲げ戻しを
行い剥離しためっき量で評価した。O: No peak of lower layer Zn Δ: Partially observed peak of lower layer Zn The sample was bent and unbended by 90'' and evaluated based on the amount of peeled plating.
○：めっき層剥離無し
Ｘ：めっき層剥離あり
表から明かな様に、本発明によって得られた鋼板の上層
めりきの均一性ならびにパウダリング性はいずれも優れ
た結果が得られた。○: No peeling of the plating layer X: Peeling of the plating layer As is clear from the table, excellent results were obtained in both the uniformity of the upper layer plating and the powdering property of the steel sheet obtained by the present invention.
〈発明の効果〉
本発明により、合金化溶融亜鉛めっき鋼板に鉄系の上層
めっきを施す２層めっき鋼板の上層めっきの均一性なら
びにパウダリング性を安定化することができ、このよう
な２層めっき鋼板の真の性能を工業的に使用可能とする
ことができ、その効果は絶大である。<Effects of the Invention> According to the present invention, it is possible to stabilize the uniformity and powdering property of the upper layer plating of a two-layer plated steel sheet in which iron-based upper layer plating is applied to an alloyed hot-dip galvanized steel sheet. The true performance of plated steel sheets can be made available for industrial use, and the effect is tremendous.
Claims (2)
２層めっき鋼板の製造方法において、鉄系電気めっきを
施す前に合金化溶融亜鉛めっき鋼板表面を弱アルカリ液
中で陰極電解処理した後に鉄系電気めっきを施すことを
特徴とする、上層鉄系電気めっきのカバリングに優れ、
かつ耐パウダリング性に優れた２層めっき鋼板の製造方
法。(1) In a method for manufacturing a two-layer coated steel sheet in which iron-based electroplating is applied on alloyed hot-dip galvanizing, the surface of the alloyed hot-dip galvanized steel sheet is subjected to cathodic electrolysis treatment in a weak alkaline solution before applying iron-based electroplating. Excellent in covering upper layer iron-based electroplating, which is characterized by applying iron-based electroplating afterwards.
A method for producing a double-layer plated steel sheet that also has excellent powdering resistance.
１に記載の上層鉄系電気めっきのカバリングに優れ、か
つ耐パウダリング性に優れた２層めっき鋼板の製造方法
。(2) The method for producing a two-layer plated steel sheet having excellent coverage of the upper layer iron-based electroplating and excellent powdering resistance according to claim 1, wherein the pH of the weak alkaline solution is 8 to 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31278589A JPH03173795A (en) | 1989-12-01 | 1989-12-01 | Production of double layer plated steel sheet having superior covering property of upper iron-based electroplating and superior powdering resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31278589A JPH03173795A (en) | 1989-12-01 | 1989-12-01 | Production of double layer plated steel sheet having superior covering property of upper iron-based electroplating and superior powdering resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03173795A true JPH03173795A (en) | 1991-07-29 |
Family
ID=18033375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31278589A Pending JPH03173795A (en) | 1989-12-01 | 1989-12-01 | Production of double layer plated steel sheet having superior covering property of upper iron-based electroplating and superior powdering resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03173795A (en) |
-
1989
- 1989-12-01 JP JP31278589A patent/JPH03173795A/en active Pending
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