JPS5947040B2 - Steel plate for containers with excellent weldability and corrosion resistance after painting and its manufacturing method - Google Patents

Description

【発明の詳細な説明】 本発明は製缶用素材として適した容器用鋼板及びその製
造法に係り、特に溶接性、耐食性塗装後の性能、特に塗
装後耐食性に優れた容器用鋼板及びその製造方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steel sheet for containers suitable as a material for making cans and a method for manufacturing the same, and in particular to a steel sheet for containers with excellent weldability and performance after coating, especially corrosion resistance after painting, and the production thereof. It is about the method.

近年、製缶方式の多様化により、缶の製造方法として電
気抵抗溶接による製缶方式（例えばスードロニツク溶接
法）が著しく発展してきている。In recent years, due to the diversification of can manufacturing methods, can manufacturing methods using electric resistance welding (for example, the Sudronik welding method) have significantly developed as a method for manufacturing cans.

しかして、これら製缶方式に供される製缶用材料として
は、容器用鋼板に要求される諸性能−耐食性、加工性、
塗装性能、塗装後耐食性等−に優れているとともに、さ
らに溶接性が著しく良好であることが要求される。本発
明は上記した電気抵抗溶接による製缶方式に供した場合
に、十分対処可能な性能を具備する安価な製缶用材料（
容器用鋼板）及びその製造方法を提供することを目的と
する。Therefore, the can-making materials used in these can-making methods include various performances required for steel sheets for containers, such as corrosion resistance, workability,
In addition to being excellent in coating performance and post-coating corrosion resistance, it is also required to have extremely good weldability. The present invention provides an inexpensive can-making material (
The purpose of this invention is to provide a steel plate for containers) and a method for manufacturing the same.

より具体的に云えば、本発明は電気抵抗溶接において、
製缶容器に対して要求される必要十分な溶接強度を得る
ための適正溶接条件の範囲が広く、又溶接部に欠陥が発
生しない広範な溶接条件を有するとともに、製缶容器に
おいて特に要求される塗装後の耐食性が著しく優れた容
器用鋼板及びその製造方法を提供せんとするものである
。従来から容器用素材としてＳｎメツキ鋼板（ブリサ）
或いは電解クロム酸処理鋼板（ＴＦＳ）が使用されてい
ることが、これら容器用素材は上記の製缶方式を対象と
した場合、各々以下の様な問題点或いは欠点を有する。More specifically, the present invention applies to electric resistance welding,
It has a wide range of appropriate welding conditions to obtain the necessary and sufficient welding strength required for can manufacturing containers, and has a wide range of welding conditions that do not cause defects in the welded part, and is especially required for can manufacturing containers. It is an object of the present invention to provide a steel plate for containers that has extremely excellent corrosion resistance after coating, and a method for manufacturing the same. Sn-plated steel sheet (Brisa) has traditionally been used as a material for containers.
Alternatively, the use of electrolytic chromic acid treated steel sheets (TFS) causes the following problems or drawbacks when these container materials are used in the above-mentioned can manufacturing method.

即ち、上記製缶方式の発展の一つの重要な理由が、製缶
コストの低減にあるため、ブリキ素材では必ずしもその
製缶コストの低減に答えるものとは云い難く、又溶接方
式による製缶方式の場合に溶接部近傍の熱影響部に於い
て鉄−錫系合金属の生成、或いはＳｎ表面の著しい加熱
酸化のため、外観変色及び塗料の密着性が劣化する等の
性能面の問題点が生じる。In other words, one of the important reasons for the development of the above-mentioned can manufacturing method is the reduction of can manufacturing costs, and it is difficult to say that tinplate material is necessarily an answer to the reduction of can manufacturing costs, and the can manufacturing method using the welding method In this case, production of iron-tin alloy in the heat-affected zone near the weld or significant thermal oxidation of the Sn surface may cause performance problems such as discoloration of the appearance and deterioration of paint adhesion. arise.

一方、電解クロム酸如理鋼板（ＴＦＳ）の場合には、そ
の経済性及びコスト面からは優れているが、ＴＦＳはそ
の被膜が金属クロム及び酸化クロムからなるクロメート
被膜から構成されている。On the other hand, electrolytic chromate steel sheets (TFS) are superior in terms of economy and cost, but the coating of TFS is composed of a chromate coating consisting of metallic chromium and chromium oxide.

そのため、これらの金属クロム及びクロメート被膜は従
来から知られている様に溶接が困難な金属或いは酸化物
のため、溶接方式による製缶方式の場合には溶接部の強
度不足がしばしば生じる欠点がある。さらに、Ｎｉメツ
キを行なつてから重クロム酸又はクロム酸の塩からなる
水溶液中で陰極処理を施したＮｉメツキ層をクロメート
被膜からなる製缶用材料（特公昭３６−１００６４）或
いはＮｉメッキを行なつてから過マンガン酸カリ等の水
溶液中で陰極処理を行なつてＮｉメツキ層とＮｉメツキ
層表面の酸化被膜を改質した製缶用材料（特公昭３６−
１５２５２）が知られている。Therefore, as is known from the past, these metal chromium and chromate coatings are metals or oxides that are difficult to weld, so when welding is used to make cans, the strength of the welded part is often insufficient. . Furthermore, after performing Ni plating, the Ni plating layer was cathodically treated in an aqueous solution consisting of dichromic acid or a salt of chromic acid. After that, the Ni plating layer and the oxide film on the surface of the Ni plating layer were modified by cathodic treatment in an aqueous solution such as potassium permanganate.
15252) is known.

しかし、これら材料に関しては、Ｎｉメツキ層とクロメ
ート被膜層を有する材料は、ＴＦＳと同様に、表面層が
酸化クロム層からなるために、上記の如くに、溶接性が
問題である。さらに、従来の公知の処理法によるクロメ
ート処理法によるクロメート被膜は大部分Ｃｒ＋３の水
酸化物のコロイド状のものからなつているがこの中にＣ
ｒ″ｆ’ も必然的に可成り含まれており、塗装後の耐
食性が光分ではない。However, regarding these materials, the materials having a Ni plating layer and a chromate coating layer have a problem in weldability, as described above, because the surface layer consists of a chromium oxide layer, similar to TFS. Furthermore, the chromate film produced by the conventional chromate treatment method is mostly composed of colloidal Cr+3 hydroxide, but this contains C.
A considerable amount of r″f′ is also inevitably included, and the corrosion resistance after painting is not measured by light.

即ち、塗膜を通して侵入した腐食水分によるＣｒ＋６の
溶出を中心としたクロメート被膜の溶解のため塗膜にフ
クレ（ブリスタ一）等の欠陥を生じ塗装後の耐食性が劣
化する。又、Ｎｉメツキ層と不動態化被膜からなる材料
は、溶接性は良好であるが、Ｎｉ金属の酸化物を主体と
する不動態化被膜は従来から知られているように塗料の
密着性、特に高温の水溶液等に長時間曝された場合の塗
料の密着性（所謂、二次塗料密着性）が良好でなく、そ
のため腐食環境において塗膜が剥離したりして、塗装後
の耐食性が必ずしも充分でない。That is, the chromate film is dissolved mainly due to the elution of Cr+6 due to corrosive moisture that has entered through the paint film, causing defects such as blisters in the paint film and deteriorating the corrosion resistance after painting. In addition, materials consisting of a Ni plating layer and a passivation film have good weldability, but a passivation film mainly composed of Ni metal oxide has problems with paint adhesion and The adhesion of paint (so-called secondary paint adhesion) is particularly poor when exposed to high-temperature aqueous solutions for long periods of time, and as a result, the paint film may peel off in corrosive environments, resulting in poor corrosion resistance after painting. Not enough.

本発明は上記した問題点を解決するとともに、電気抵抗
溶接による製缶方式に供しても十分対処可能な性能を具
備する安価な容器用鋼板及びその製造する方法を提供す
ることを目的とする。It is an object of the present invention to solve the above-mentioned problems and to provide an inexpensive steel sheet for containers that has sufficient performance even when used in a can-making method using electric resistance welding, and a method for manufacturing the same.

即ち、本発明は、耐食性、溶接性、塗装性能、特に塗装
後耐食性に優れた容器用鋼板及びその製造方法を提供せ
んとするものである。上記目的を達成するための本発明
の容器用鋼板は、鋼板の表面に厚さ０．０１〜 ０．３
０μのＮｉメツキ層、その表面に被膜量１０ｍ９／ｗ？
以下の金属クロム層、さらにその表面にクロメート被膜
層を設けるとともに、該クロメート被膜層の被膜量がＣ
ｒ換算量で金属クロム層との総和で２０ｍｇ／一以下か
らなり、かつ該クロメート被膜中の酸素原子に対するｓ
原子の比率を分光分析スペクトル測定法によるピーク強
変比率（以下、比率と略称する）で表わして０．１５以
下で、Ｃｒ−０Ｈ系オール結合に対するＣｒ−０系オキ
ソ結合の比率が該クロメート被膜の表面で０．９０以上
からなることを特徴とする。That is, the present invention aims to provide a steel plate for containers that is excellent in corrosion resistance, weldability, and painting performance, especially corrosion resistance after painting, and a method for manufacturing the same. The steel plate for containers of the present invention for achieving the above object has a thickness of 0.01 to 0.3 on the surface of the steel plate.
0μ Ni plating layer, coating amount 10m9/w on its surface?
The following metal chromium layer is further provided with a chromate coating layer on its surface, and the coating amount of the chromate coating layer is C
It consists of 20 mg/l or less in total with the metal chromium layer in r equivalent amount, and s with respect to oxygen atoms in the chromate coating.
The ratio of atoms expressed as a peak intensity ratio (hereinafter referred to as ratio) measured by spectroscopic analysis is 0.15 or less, and the ratio of Cr-0-based oxo bonds to Cr-0H-based all bonds is in the chromate coating. It is characterized by having a surface roughness of 0.90 or more.

又、上記の如き構成の被覆層を有する溶接用鋼板の製造
法は、鋼板の表面に厚さ０．０１〜 ０．３０μのＮｉ
メツキ層を施し、続いてＳＯ４−２／Ｃｒ＋６の重量比
（以下、比と略称する）が１／４０以下からなるＳＯ，
−２を含有するクロム酸の水溶液中で電流密度７．５Ａ
／ Ｄｍ２をこえ２５Ａ／Ｄｍ２以下でかっ電気量２．
５クーロン／Ｄｗ？以上で陰極電解処理を行ない、被膜
量が１０７ｎｇ／一以下の金属Ｃｒ層とこの表面にクロ
メート被膜をＣｒ換算量で金属Ｃｒとの総和が２０巧／
ｄ以下の被膜量で設けてから直ちに或いは水洗して、便
に温度６５〜１００℃、ＰＨ４以上の高温水による処理
を行なつて、該クロメート被膜中の酸素原子に対するＳ
原子の比率が０．１５以下でかつ該被膜表面でのＣｒ−
０Ｈ系オール結合に対するＣｒ−０系オキソ結合の比率
が０．９０以上であるクロメート被膜を形成することを
特徴とする。In addition, a method for manufacturing a welding steel plate having a coating layer having the above-mentioned structure includes a method of manufacturing a welding steel plate having a coating layer with a thickness of 0.01 to 0.30μ on the surface of the steel plate.
A plating layer is applied, followed by SO having a weight ratio of SO4-2/Cr+6 (hereinafter abbreviated as ratio) of 1/40 or less,
Current density 7.5 A in an aqueous solution of chromic acid containing -2
/ Amount of electricity exceeding 25A/Dm2 and less than 25A/Dm2.
5 coulombs/Dw? A cathodic electrolytic treatment is performed in the above manner, and a metal Cr layer with a coating amount of 107 ng/1 or less and a chromate coating on this surface are added to a chromate coating with a Cr conversion amount of 20 ng/1 or less.
Immediately after applying a film with a coating amount of d or less, or after washing with water, the stool is treated with high-temperature water with a temperature of 65 to 100°C and a pH of 4 or more to reduce the amount of S against oxygen atoms in the chromate film.
The atomic ratio is 0.15 or less and the Cr-
It is characterized by forming a chromate film in which the ratio of Cr-0 type oxo bonds to 0H type all bonds is 0.90 or more.

即ち、本発明の方法においては、Ｎｉメツキ層で主とし
て耐食性の向上を計るとともに、Ｃｒ″＋１１Ｓ−ＳＯ
４−ー系浴によるクロメ＝−ト処理を施して、Ｎｉメツ
キ面に公知のクロメート被膜と比較して、ピンホールが
少なく、耐食性の優れた金属クロムとクロメート被膜か
らなる被膜層を形成せしめるとともに、クロメート被膜
中に含有されるＳＯ４−ーイオン、Ｃｒ＋６イオンの量
が少なく、又Ｃｒ−０系のオキン結合を主体とする水和
度の小さい被膜を形成せしめるクロメート処理を行なう
ことによつて、溶接性を損なうことなく、耐食性、塗装
性能、特に塗装後の耐食性を向上せしめることを目的と
して構成されている。That is, in the method of the present invention, the Ni plating layer is mainly used to improve corrosion resistance, and the Cr''+11S-SO
By applying chromate treatment using a 4-based bath, a coating layer consisting of metallic chromium and chromate coating is formed on the Ni plating surface, which has fewer pinholes and has excellent corrosion resistance compared to known chromate coatings. , welding by performing chromate treatment to form a film with a small amount of SO4- ions and Cr+6 ions contained in the chromate film, and a film with a low degree of hydration mainly composed of Cr-0-based okyne bonds. It is designed to improve corrosion resistance and coating performance, especially corrosion resistance after coating, without impairing properties.

一般に、Ｎｉ金属自体はその耐食性が良好であり、又溶
接性も良好である。しかし、Ｎｉメツキ層は如何に良好
なメツキを行なつてもピンホールが存在するので、その
ピンホールからの腐食防止及びＮｉ金属自体の溶出を避
けるため、他の製缶用メツキ鋼板（Ｓｎメツキ鋼板、ク
ロムメツキ鋼板等）と同様に、本発明の容器用鋼板も大
部分の容器用の用途に対してはラツカ一塗装されて使用
される。従つて、本発明のＮｉメツキを施した容器用鋼
板も優れた塗装性能が要求されるが、Ｎｉメツキ層はそ
の表面に生成される酸化膜のためか塗装性能が著しく劣
る。而して、このＮｉメツキ層の塗装性能を改良するた
めに、従来からクロメート処理を施すことは前記の如く
（特公昭３６−１００６４）提案されている。Generally, Ni metal itself has good corrosion resistance and good weldability. However, no matter how well the Ni plating layer is plated, pinholes still exist, so in order to prevent corrosion from the pinholes and to avoid elution of the Ni metal itself, other plating steel sheets for can manufacturing (Sn plating (e.g. steel plates, chrome-plated steel plates, etc.), the steel plates for containers of the present invention are also used with a gloss coating for most container applications. Therefore, the Ni-plated steel sheet for containers of the present invention is also required to have excellent coating performance, but the coating performance of the Ni-plated layer is significantly inferior, probably due to the oxide film formed on its surface. In order to improve the coating performance of this Ni plating layer, it has been proposed to perform chromate treatment as described above (Japanese Patent Publication No. 36-10064).

しかしながら、Ｎｉメツキ層に公知の方法でクロメート
処理を施すのみでは、本発明の目的とする性能が得られ
なかつた。即ち、公知のクロメート処理法では塗料の密
着性が塗装置後では著しく良好であるが、塗装してから
腐食水溶液に長期間曝される製缶容器における腐食環境
を想定した腐食試験において、塗膜を通して侵入してく
る腐食水溶液によつて塗膜面にフクレ（ブリスタ一）を
生じ、塗膜剥離が生じるとともに、又塗膜の欠陥部にお
いてはこの傾向がさらに激しく起こる等塗装後の耐食性
が著しく劣つた。又、この公知の方法によるクロメート
処理後の電気抵抗溶接法による溶接性はあまり良好でな
く、被膜量が多い場合には均一な溶接ナゲツトの生成が
困難で充分な溶接強度を得るのが困難であり、又被膜量
が少ない場合にも、Ｃｒ−０Ｈ系の水和度の高いクロメ
ート被膜の影響のためか均一良好な溶接部が得られず、
溶接部にしばしば゛溶接チリ″゛と呼ばれる溶接欠陥を
生じる傾向が見られ、その溶接性があまり良好でなかつ
た。However, the performance aimed at by the present invention could not be obtained only by subjecting the Ni plating layer to chromate treatment using a known method. In other words, with the known chromate treatment method, the adhesion of the paint is extremely good after painting, but in a corrosion test assuming a corrosive environment in can manufacturing containers that are exposed to a corrosive aqueous solution for a long period of time after painting, the paint film was The corrosive aqueous solution that enters through the coating causes blisters on the paint surface, which causes the paint to peel off, and this tendency becomes even more severe in defective areas of the paint, resulting in a significant decrease in corrosion resistance after painting. It was inferior. Furthermore, weldability by electric resistance welding after chromate treatment by this known method is not very good, and when the amount of coating is large, it is difficult to generate uniform weld nuggets and it is difficult to obtain sufficient welding strength. Also, even when the amount of coating is small, a uniform and good weld cannot be obtained, probably due to the influence of the highly hydrated chromate coating of the Cr-0H system.
There was a tendency for welding defects, often referred to as ``welding chips'', to occur in welded areas, and weldability was not very good.

従つて、これらの耐食性、塗装性能及び溶接性を改良す
るための検討を種々行なつた結果、公知の方法によるク
ロメート被膜を改良して、Ｎｉメツキ層に電気抵抗によ
る溶接性を損なわない適正被膜量の金属Ｃｒ層とクロメ
ート被膜からなる二層被覆層を形成して、耐食性の向上
を計るとともに、表面の該クロメート被膜中に含有され
る腐食水溶液に対して可溶成分であるＳＯ４−一）Ｃｒ
＋ｓイオンを溶出せしめ、かつコロイド状のＣｒ＋３の
水酸化物からなるクロメート被膜の脱水、縮合反応を促
進せしめたオキソ化度（クロメート被膜中のＣｒ−０Ｈ
系オール結合に対するＣｒ−０系のオキソ結合の比率）
の高い、即ち水和度の低い難溶性のクロメート被膜を金
属Ｃｒ層からなる被膜を介してＮｉメツキ層表面に適正
量形成せしめれば良いことが判つた。即ち、塗膜下にお
いて腐食水溶液に曝された場合にＮｉメツキ層の表面に
形成せしめたクロメート処理被膜のピンホール部からの
Ｎｉメツキ層の腐食が少なく、又表面クロメート被膜か
らの可溶性成分の溶解によつて生じる塗膜のフクレ等が
生じにくく、さらに溶接電流が均一に流れやすいクロメ
ート処理被膜として、種々検討の結果、（１）Ｓσ「２
／Ｃｒ＋６の比が１／４０以下からなるＳＯ「２を含有
するクロム酸の水溶液中での電流密度７．５Ａ／Ｄｄを
こえ２５Ａ／Ｄｄ以下の範囲での陰極電解処理により、
金属Ｃｒ層の被膜量を１０ｍｆ！／ｄ以下、又この金属
Ｃｒ層表面にＣｒ換算量で金属Ｃｒ層との総和で２０巧
／ｄ以下に構成されるクロメート被膜層を設け、ピンホ
ールが少なく、耐食性が優れたクロメート処理被膜を形
成させる。Therefore, as a result of various studies to improve these corrosion resistance, coating performance, and weldability, we improved the chromate coating by a known method and created an appropriate coating for the Ni plating layer that does not impair weldability due to electrical resistance. A two-layer coating layer consisting of a metal Cr layer and a chromate film is formed to improve corrosion resistance, and the chromate film on the surface contains a soluble component in a corrosive aqueous solution, SO4-1). Cr
The degree of oxation (Cr-0H in the chromate film) caused +s ions to elute and promoted the dehydration and condensation reaction of the chromate film made of colloidal Cr+3 hydroxide.
Ratio of Cr-0 system oxo bonds to system all bonds)
It has been found that it is sufficient to form an appropriate amount of a poorly soluble chromate film with a high degree of hydration, that is, a low degree of hydration, on the surface of the Ni plating layer via a film made of a metal Cr layer. In other words, when the Ni plating layer is exposed to a corrosive aqueous solution under the coating, there is less corrosion of the Ni plating layer through the pinholes of the chromate treatment film formed on the surface of the Ni plating layer, and there is less dissolution of soluble components from the surface chromate film. As a result of various studies, we have found that (1) Sσ'2
/Cr+6 ratio is 1/40 or less by cathodic electrolytic treatment in an aqueous solution of chromic acid containing SO2 at a current density of more than 7.5 A/Dd and less than 25 A/Dd,
The coating amount of the metal Cr layer is 10mf! /d or less, and on the surface of this metal Cr layer, a chromate coating layer with a Cr equivalent amount of 20/d or less in total with the metal Cr layer is provided to create a chromate treatment coating with few pinholes and excellent corrosion resistance. Let it form.

（２）クロメート被膜中に含有されるｓσ「”イオン含
有量を極力溶出せしめ、クロメート被膜中の酸素原子と
ｓ原子の比率、即ちＳ／０を０．１５以下、好ましくは
０．１０以下にする。(2) The sσ "" ion content contained in the chromate film is eluted as much as possible, and the ratio of oxygen atoms to s atoms in the chromate film, that is, S/0, is 0.15 or less, preferably 0.10 or less. do.

（ ｌ）クロメート被膜中に含有されるＣｒ＋６イオン
を極力溶出させ、かつクロメート被膜を主として構成す
るコロイド状のＣｒ゛３の水酸化物の脱水、縮合反応を
行なしめて、クロメート被膜中のＣｒ−０Ｈ系オール結
合に対するＣｒ−ｏ系のオキソ結合の比率が０．９０以
上、好ましくは０．９５以上に高めることが各々良好な
結果が得られることが分つた。(l) The Cr+6 ions contained in the chromate film are eluted as much as possible, and the hydroxide of colloidal Cr゛3, which mainly constitutes the chromate film, is dehydrated and condensed to remove Cr- in the chromate film. It has been found that good results can be obtained by increasing the ratio of Cr-o type oxo bonds to 0H type all bonds to 0.90 or more, preferably 0.95 or more.

本発明の方法において、このクロメート被膜中に含有さ
れるＳＯ７２の量は、クロメート被膜量自体が非常に少
ない（Ｃｒ換算量として最高２０Ｗ９／一未満）ため、
ＳＯ７−の絶対量として求める事は煩雑である。In the method of the present invention, the amount of SO72 contained in this chromate film is very small (maximum less than 20W9/1 as Cr equivalent amount), so
It is complicated to obtain the absolute amount of SO7-.

従つて、オージエ分光分析法により、クロメート被膜を
構成する。（酸素）原子に対するｓ原子の比率を、それ
ぞれの原子の濃度に比例するピーク強度比率で表わす。
本発明においてオージエ分光分析法で求めたクロメート
被膜中の酸素原子に対するｓ原子の比率が最大０．１５
以下、好ましくは０．１０以下になる様に、クロメート
被膜中のＳＯ４−ーイオンの溶出を行なわしめる事が必
要であることが判つた。又、ォキソ化度を正確に求める
ことは、非常に困難であり、このクロメート被膜のオキ
ソ化度を従来から学会等で報告されている様に、オージ
エ分光分析で求められるＣｒのオージエ・ピーク強度に
関して、Ｃｒピークのバツクグラウンドから求められる
Ｃｒピークの高さ（Ｈ１ ）に対して、クロム酸化物の
形態によつて各々異なるＣｒピークの最高値と最小値の
差（Ｈ２）の比率（Ｈ，／Ｈ２）によつて求められる値
をオキソ度として表示した場合の値である。Therefore, a chromate coating is constructed using Auger spectroscopy. The ratio of s atoms to (oxygen) atoms is expressed as a peak intensity ratio proportional to the concentration of each atom.
In the present invention, the ratio of s atoms to oxygen atoms in the chromate film determined by Augier spectroscopy is at most 0.15.
It has been found that it is necessary to elute SO4- ions from the chromate film so that the value becomes preferably 0.10 or less. In addition, it is very difficult to accurately determine the degree of oxo-ization of this chromate film, and as has been reported at academic conferences, the Auger peak intensity of Cr determined by Auger spectroscopy is Regarding the height of the Cr peak (H1) determined from the background of the Cr peak, the ratio (H, /H2) is expressed as an oxo degree.

本発明の方法では、０．９０以上、好ましくは０．９５
以上高めることが必要であることが判つた。以下本発明
の内容を詳細に説明する。In the method of the present invention, 0.90 or more, preferably 0.95
It was found that it was necessary to increase the The contents of the present invention will be explained in detail below.

Ｎｉメツキは主として耐食性の向上を目的として実施す
るものであり、そのメツキ手段は通常の電気ニツケルメ
ツキ方式を採用すればよい。Ｎｉメツキ浴の組成、メツ
キ条件等は特に規定しないが、本体電流密度は３〜３０
０Ａ／ｄイ、メツキ温度は７０℃以下である。Ｎｉメツ
キ浴の組成例およびメツキ条件例を挙げれば下記の如く
である。また、本発明ではこのＮｉメツキの厚みを０．
０１〜０．３μと規定したが、これは下限より厚みが薄
くなると耐食性が不十分でＮｉメツキの意味がなくなり
、また上限より厚くなると効果が飽和しコスト的に不利
になると、との理由による。Ni plating is carried out mainly for the purpose of improving corrosion resistance, and the plating means may be a normal electric nickel plating method. The composition of the Ni plating bath, plating conditions, etc. are not particularly specified, but the current density of the main body is 3 to 30
0A/d, plating temperature is 70°C or less. Examples of the composition of the Ni plating bath and plating conditions are as follows. In addition, in the present invention, the thickness of this Ni plating is set to 0.
The reason for this is that if the thickness is thinner than the lower limit, the corrosion resistance will be insufficient and the Ni plating will be meaningless, and if it is thicker than the upper limit, the effect will be saturated and it will be disadvantageous in terms of cost. .

このＮｉメツキを鋼ストリツプ表面に施したのみでは、
溶接性は良好であるが、容器用素材として十分な特性を
具備しているとは云い難い。If only this Ni plating is applied to the surface of the steel strip,
Although it has good weldability, it cannot be said that it has sufficient properties as a container material.

即ち、塗料の密着性、塗装後の耐食住がＮｉメツキ層の
みでは、Ｎｉメツキ表面に生成する酸化膜のためか著し
く劣る。このため本発明では、Ｎｉメツキに引き続き、
ＳＯ，Πがクロム酸中にＣｒｆ６の１／４０以下の割合
で含有される水溶液中で電流密度を７．５Ａ／Ｄｒｒ？
をこえ、２５Ａ／Ｄｒｒ？以下の範囲で電気量２．５ク
ーロン／ｄイ以上の条件で陰極電解処理を行ない、Ｎｉ
メツキ層表面に被膜量１０岬／一以下の金属Ｃｒ層、さ
らにその表面にＣｒ換算量で金属Ｃｒとの総和が２０Ｗ
Ｉｇ／イ以下のクロメート被膜層が生成されるクロメー
ト処理を行なつてから、更にＰＨ４以上の温度６５〜１
００℃からなる高温水により０．３〜１０秒間の高温水
処理を行なつて、電気抵抗による溶接性、耐食性、塗装
性能、特に腐食水溶液に曝された場合の塗装後耐食性を
著しく向上せしめている。That is, the adhesion of the paint and the corrosion resistance after painting are significantly inferior if the Ni plating layer is used alone, probably due to the oxide film formed on the Ni plating surface. Therefore, in the present invention, following Ni plating,
In an aqueous solution in which SO, Π is contained in chromic acid at a ratio of 1/40 or less of Crf6, the current density is set to 7.5 A/Drr?
Beyond 25A/Drr? Cathodic electrolytic treatment was performed under the following conditions with an amount of electricity of 2.5 coulombs/di or more, and Ni
A metal Cr layer with a coating amount of 10 capes/1 or less on the surface of the plating layer, and a total of 20 W with metal Cr on the surface in terms of Cr conversion amount.
After performing the chromate treatment that produces a chromate coating layer with an Ig/I or lower temperature, the temperature is further increased to 65-1 at a pH of 4 or higher.
By performing high-temperature water treatment for 0.3 to 10 seconds with high-temperature water consisting of 00℃, weldability based on electrical resistance, corrosion resistance, coating performance, and especially corrosion resistance after coating when exposed to corrosive aqueous solutions, are significantly improved. There is.

即ち、本発明の方法においては、Ｎｉメツキ層表面に施
される従来のクロメート処理法に比較して、ＳＯ４−２
をＣｒ＋６に対して１／４０以下、好ましくは１／５０
以下含有せしめたクロメート処理浴を用い、電流密度を
７．５Ａ／ Ｄｒｒ？をこえ、２５Ａ／Ｄｗ？以下での
陰極電解処理と温度６５〜１００℃、ＰＨ４以上の高温
水処理により、Ｎｉメツキ層表面に金属Ｃｒ層と難溶性
のクロメート被膜の二層クロメート処理被膜を設けるこ
とを必須としている。That is, in the method of the present invention, SO4-2
1/40 or less, preferably 1/50 of Cr+6
Using a chromate treatment bath containing the following, the current density was set to 7.5A/Drr? Beyond 25A/Dw? It is essential to provide a two-layer chromate treatment film consisting of a metal Cr layer and a sparsely soluble chromate film on the surface of the Ni plating layer by cathodic electrolysis treatment and high temperature water treatment at a temperature of 65 to 100° C. and a pH of 4 or more as described below.

而して、本発明の如く、Ｎｉメツキ層表面に金属Ｃｒ層
とクロメート被膜のｊ被膜からなるクロメート処理被膜
を施すことにより、従来のＮｉメツキ層表面のクロメー
ト処理法に比較して、その耐食性の向上、特に処理被膜
のピンホールを著しく少なくしうることは当然考えられ
ることであるが、本発明の目的とする電気抵抗による溶
接性に対して、金属Ｃｒはその融点が著しく高く、又電
気抵抗がＮｉ金属等に比して著しく大きいためか、その
溶接性、特に均一なナゲツト生成を著しく阻害する。Therefore, by applying a chromate treatment film consisting of a metal Cr layer and a chromate film to the surface of the Ni plating layer as in the present invention, the corrosion resistance is improved compared to the conventional chromate treatment method for the surface of the Ni plating layer. Of course, it is possible to significantly reduce the number of pinholes in the treated film, but metal Cr has a significantly high melting point and has a significantly high weldability due to electrical resistance, which is the objective of the present invention. Perhaps because the resistance is significantly greater than that of Ni metal, etc., it significantly impedes weldability, particularly uniform nugget formation.

そこで、溶接性を損なわない金属Ｃｒ層の被膜量とその
表面に必然的に必ず生成されるクロメート被膜量及びク
ロメート被膜組成について、種々検討した結果、金属Ｃ
ｒ層の被膜量は１０７Ｖ／ｄ以下、好ましくは５７！１
ｆ／ｄ以下、又該金属Ｃｒ層の表面に生成されるクロメ
ート被膜は、Ｃｒ換算量で金属Ｃｒ量との総和で２０ワ
／ｄ以下、好ましくは１０７７Ｖ／ｗ？以下の被膜量で
あるとともに、オキソ化度の高い、即ち水和度の低いク
ロメート被膜で構成すれば、均一なナゲツト生成と充分
な溶接強度が得られる適正溶接範囲が得られ、溶接部に
チリ発生等の溶接欠陥が生じにくいことが判つた。さら
に、このような被膜量１０７７Ｖ／ｄ以下の金属Ｃｒ層
は、上記の如きＳＯ「２イオンが含有されるクロメート
浴で電流密度が７．５〜２５Ａ／Ｄｄの範囲で陰極電解
処理を行うことにより、電解時間の調整だけで容易に得
られる。Therefore, as a result of various studies on the amount of the metal Cr layer that does not impair weldability, the amount of chromate film that is inevitably generated on the surface, and the composition of the chromate film, we found that
The coating amount of the r layer is 107 V/d or less, preferably 57!1
f/d or less, and the chromate film formed on the surface of the metal Cr layer has a Cr equivalent amount of 20 W/d or less, preferably 1077 V/w? If the coating amount is as follows and the chromate coating has a high degree of oxidation, that is, a low degree of hydration, an appropriate welding range for uniform nugget formation and sufficient welding strength will be obtained, and there will be no dust in the weld zone. It was found that welding defects such as welding defects were less likely to occur. Furthermore, such a metal Cr layer with a coating amount of 1077 V/d or less may be subjected to cathodic electrolytic treatment at a current density in the range of 7.5 to 25 A/Dd in a chromate bath containing SO2 ions as described above. Therefore, it can be easily obtained by simply adjusting the electrolysis time.

図はＮｉメツキ鋼板を供試材にして各電流密度で電解処
理した場合の金属Ｃｒ析出量を示す。電流密度が７．５
Ａ／Ｄｗ？以下では、電解時間を如何に長くしてもＮｉ
メツキ表面で、金属Ｃｒ層が生成され難い。また電流密
度が２５Ａ／Ｄｄを越えると短時間の電解処理で１０７
Ｖ／ｗ？を越える過剰な金属Ｃｒ量を析出し、溶接性特
に均一なナゲツトの生成を著しく阻害する。したがつて
本発明は、上記のような溶接性と耐食性も考慮して電流
密度を７．５〜２５Ａ／Ｄｎ！に限定した。又、この金
属Ｃｒ層表面に、上記処理浴における陰極電解処理では
必然的にクロメート被膜が形成される。The figure shows the amount of metallic Cr precipitated when a Ni-plated steel plate was subjected to electrolytic treatment at various current densities. Current density is 7.5
A/Dw? Below, no matter how long the electrolysis time is, Ni
A metal Cr layer is difficult to form on the plating surface. In addition, when the current density exceeds 25A/Dd, 107
V/w? This precipitates an excessive amount of metallic Cr exceeding 100%, which significantly impedes weldability, particularly the formation of uniform nuggets. Therefore, in the present invention, the current density is set to 7.5 to 25 A/Dn! considering the above-mentioned weldability and corrosion resistance! limited to. Furthermore, a chromate film is inevitably formed on the surface of this metal Cr layer during the cathodic electrolytic treatment in the above treatment bath.

該クロメート被膜は主としてコロイド状の水酸化物で構
成されるとともに、その中に必然的に少量のＣｒ＋０や
ＳＯ「２イオンを含んでいる。従つて、本発明では陰極
電解処理後直ちに或いは水洗してから、被膜の改質を行
なうために、温度６５〜１００℃、好ましくは７５〜９
５℃、ＰＨ４以上、好ましくはＰＨ６〜９の高温水によ
る処理が行なわれる。即ち、クロメート被膜中に含有さ
れる可溶成分であるＳＯ「−イオンの溶出及びＣｒ＋６
の溶出、コロイド状のＣｒ＋３の水酸化物の脱水、縮合
反応等の促進により、被膜中に含有される可溶性成分（
ＳＯご，Ｃｒ＋４）が非常に少なく又オキソ化度の高い
、即ち水和度の低いクロメート被膜で構成される。更に
、本発明においては、上記の如く、可溶性成分の含有量
が少なく、又オキソ化度の高いクロメート被膜をその被
膜量がＣｒ量で換算して金属Ｃｒ層との総和で２０１１
ｆ／イ以下、好ましくは１０巧／ｄ以下に限定・構成す
ることが重要である。上記の処理法により、かつクロメ
ート処理による被膜量を限定することにより、そのクロ
メート処理被膜はピンホールが少なく、被膜中のＳＯ７
２イオンの量が少ない、即ち酸素原子に対するＳ原子の
比率が０．１５以下、好ましくは０．１０以上に確保さ
れるとともに、オキソ化度が０．９０以上、好ましくは
０．９５以上に確保されているので、本発明の容器用鋼
板の耐食性は良好であり、又クロメート被膜は腐食水溶
液に曝された場合に難溶性となり、塗膜下でのクロメー
ト被膜からの溶出或いはクロメート処理被膜ピンホール
部からのＮｉメツキ層からの腐食生成物等の溶出が少な
く、塗装後耐食性が著しく優れている。The chromate film is mainly composed of colloidal hydroxide, and inevitably contains small amounts of Cr+0 and SO2 ions. Therefore, in the present invention, the chromate film is treated immediately after cathodic electrolytic treatment or after washing with water. After that, in order to modify the film, the temperature is 65-100°C, preferably 75-90°C.
Treatment is performed with high temperature water at 5° C. and a pH of 4 or more, preferably 6 to 9. That is, the elution of SO'- ions, which are soluble components contained in the chromate film, and the elution of Cr+6
The soluble components contained in the coating (
It is composed of a chromate film that contains very little SO, Cr+4) and has a high degree of oxidation, that is, a low degree of hydration. Furthermore, in the present invention, as mentioned above, a chromate coating with a low content of soluble components and a high degree of oxo conversion has a coating amount of 2011 in terms of the amount of Cr, and the total amount with the metal Cr layer.
It is important to limit and configure it to less than f/i, preferably less than 10 f/d. By using the above treatment method and by limiting the amount of coating by chromate treatment, the chromate treatment coating has fewer pinholes and the SO7 in the coating is
The amount of 2 ions is small, that is, the ratio of S atoms to oxygen atoms is ensured at 0.15 or less, preferably 0.10 or more, and the degree of oxation is ensured at 0.90 or more, preferably 0.95 or more. Therefore, the corrosion resistance of the steel sheet for containers of the present invention is good, and the chromate coating becomes poorly soluble when exposed to a corrosive aqueous solution, resulting in leaching from the chromate coating under the coating or pinholes in the chromate treatment coating. There is little elution of corrosion products etc. from the Ni plating layer, and the corrosion resistance after painting is extremely excellent.

而して、上記構成の金属Ｃｒ層とクロメート被膜を形成
する方法として、ピンホールの少ないクロメート処理被
膜を得るためにはＳＯ「２イオンを含有するクロメート
浴での処理が前記の如く必要である。As a method for forming a chromate coating with a metal Cr layer having the above structure, treatment in a chromate bath containing SO2 ions is necessary as described above in order to obtain a chromate-treated coating with few pinholes. .

この処理浴においてＳＯ４２イオンの量がＣｒ＋６に対
して、１／４０をこえると陰極処理に続いて行なわれる
高温水処理においてクロメート被膜から充分に溶出させ
るのが困難になるので１／４０以下、好ましくは１／５
０以下に少なくするのが望ましい。又、陰極電解処理に
よるクロメート処理被膜形成後の高温水処理艮クロメー
ト被膜中のＳＯｊ４イオン、Ｃｒ＋６イオンの溶出及び
コロイド状のＣｒ＋３の水酸化物の脱水、縮合反応の促
進に絶対必要である。In this treatment bath, if the amount of SO42 ions exceeds 1/40 of Cr+6, it will be difficult to sufficiently elute it from the chromate film in the high temperature water treatment that follows the cathode treatment, so it is preferably 1/40 or less. is 1/5
It is desirable to reduce it to 0 or less. In addition, high-temperature water treatment after the formation of a chromate treatment film by cathodic electrolysis treatment is absolutely necessary for elution of SOj4 ions and Cr+6 ions in the chromate film, dehydration of colloidal Cr+3 hydroxide, and promotion of the condensation reaction.

そして、この高温水処理における水質はＳＯ４′，Ｃｒ
＋６のクロメート被膜からの溶出、除去を短時間で行な
わしめるために重要であり、ＰＨが４未満ではＳＯ７２
，Ｃｒ″Ｆ６の溶出が妨げられるとともに、またクロメ
ート被膜中への処理水溶液から再浸透するため好ましく
ない。ＰＨが１０をこえる場合には、クロメート被膜を
溶解する恐れがあるので、ＰＨが１０以下のものが使用
されることになる。特に、溶出速度を考慮した場合ＰＨ
６〜９の範囲に於いても最も好ましく、炭酸アンモン、
炭酸ソーダー等でＰＨ調整を行なつてもよい。また、こ
の高温水に対する陰極電解処理浴の持ち込み或いはクロ
メート被膜から溶出するＣｒｆ６、陰イオンの処理水溶
液中に含有される量は各々Ｃｒ＋６１０ｔ／Ｔ，．ｓＯ
「２１ｆ／ｔ以下であり、かつＰＨが上記範囲を満足す
れば充分であり、この範囲をこえるとクロメート被膜か
らのＳＯ．一陰イオン及びＣｒ＋６の溶出を妨げるため
か、本発明の目的を満足しなくなる。The water quality in this high temperature water treatment is SO4', Cr
This is important for elution and removal from the +6 chromate film in a short time, and if the pH is less than 4, SO72
, Cr"F6 is prevented from elution, and also re-permeates into the chromate film from the treated aqueous solution, which is undesirable. If the pH exceeds 10, there is a risk of dissolving the chromate film, so if the pH is less than 10. In particular, when considering the elution rate, pH
The most preferred range is from 6 to 9, ammonium carbonate,
The pH may be adjusted using carbonate soda or the like. In addition, the amounts of Crf6 and anions contained in the treated water solution, which are eluted from the cathode electrolytic treatment bath or the chromate film, are Cr+610t/T, . sO
"It is sufficient that the pH is 21 f/t or less and the pH satisfies the above range. If the pH exceeds this range, the purpose of the present invention is satisfied, probably because the elution of SO. monoanions and Cr+6 from the chromate film is hindered. I won't.

次に、本発明の処理において重要な条件は、処理に使用
される水の温度及び処理時間である。Next, important conditions in the treatment of the present invention are the temperature of the water used in the treatment and the treatment time.

温度は６５〜１００℃、処理時間は０．３秒〜１０秒と
されるべきである。即ち、本発明の方法によるクロメー
ト被膜の形成を工業生産に対処して行なわＬ．めるため
には、短時間で上述のクロメート被膜からのＳＯ４−２
イオン及びＣｒ÷ の溶出を出来るだけ短時間に行なう
ため、高温処理が当然必要であるとともに、これら溶出
に加うるにクロメート被膜のオキソ化度を向上させて、
クロメート被膜が塗装後腐食環境に曝された場合、難溶
性にするために絶対に必要である。即ち、処理水の温度
が６５℃以下では、上記処理時間の範囲でＳＯ４−２イ
オン及びＣｒ＋６の溶出が光分でなく、またクロメート
被膜のオキソ化度が元分でないためか、本発明の目的と
する効果が得られない。The temperature should be 65-100°C and the treatment time should be 0.3 seconds to 10 seconds. That is, the formation of a chromate film by the method of the present invention can be carried out in response to industrial production. In order to
In order to elute ions and Cr÷ in as short a time as possible, high-temperature treatment is naturally necessary, and in addition to these elutions, the degree of oxation of the chromate film is improved.
This is absolutely necessary to make the chromate coating poorly soluble if it is exposed to a corrosive environment after painting. That is, when the temperature of the treated water is 65° C. or lower, the elution of SO4-2 ions and Cr+6 is not in the light fraction within the above treatment time range, and the degree of oxation of the chromate film is not in the elemental fraction. This effect cannot be obtained.

また処理水の温度が１００℃以上では、経済的でなくな
るとともに、電解クロム酸処理鋼板にこの水蒸気が接触
しても直ちに液状水になりがたいため、クロメート被膜
からの水による溶出効果がなくなるため、処理水溶液の
温度を１００℃以上にする事は好ましくない。Furthermore, if the temperature of the treated water is 100°C or higher, it will not be economical, and even if this water vapor comes into contact with the electrolytic chromate treated steel sheet, it will not turn into liquid water immediately, so the elution effect of water from the chromate coating will disappear. It is not preferable to raise the temperature of the treated aqueous solution to 100°C or higher.

処理時間については、０．３秒以上の処理時間でなけれ
ば、クロメート被膜からのＳＯ「２イオンの溶出及びＣ
ｒ＋６の溶出が光分でなく、クロメート被膜のオキソ化
度向上が充分でなく、本発明の目的とする効果が得られ
ず、また１０秒以上の処理時間では工業的にあまり経済
的でなく、使用水中のＳＯ４−ー等陰イオン或いは水中
に含まれる他の不純物等の再浸透により、クロメート被
膜中に溶出しやすい成分が含有される悪影響が生じるの
で処理時間は１０秒以下に限定される。伺、本発明の高
温水の適用方法であるが、前述の条件を満足するもので
あれば、浸漬処理、スプレィによる噴射処理、高温水蒸
気と低温水溶液の混合温湯による噴射処理いずれでも良
い。かくの如くして形成された前記構成の金属Ｃｒ層と
クロメート被膜からなる二層クロメート処理被膜は、Ｎ
ｉメツキ層表面に対してピンホールが著しく少なく、耐
食性が良好であるとともに、表面被膜層を形成するクロ
メート被膜は難溶性のクロメート被膜で構成されるため
塗装性能、特に塗装後耐食性が著しく優れている。Regarding the treatment time, unless the treatment time is 0.3 seconds or more, the elution of SO2 ions and C
The elution of r+6 is not optical, the degree of oxidation of the chromate film is not sufficiently improved, the desired effect of the present invention cannot be obtained, and a treatment time of 10 seconds or more is not industrially economical. The treatment time is limited to 10 seconds or less because re-penetration of anions such as SO4 in the water used or other impurities contained in the water causes the chromate film to contain components that are easily eluted. Regarding the method of applying high-temperature water according to the present invention, any of immersion treatment, spray treatment, and injection treatment with a hot water mixture of high-temperature steam and low-temperature aqueous solution may be used as long as the above-mentioned conditions are satisfied. The two-layer chromate treatment film formed in this manner, consisting of the metal Cr layer and the chromate film, has the above-mentioned structure.
There are very few pinholes on the surface of the plating layer, and it has good corrosion resistance.The chromate film that forms the surface coating layer is composed of a hardly soluble chromate film, so the coating performance, especially the corrosion resistance after painting, is extremely excellent. There is.

さらに、金属Ｃｒ層が１０ｍｇ／ｗ？以下で、かつ表面
のクロメート被膜がオキソ化度が高く、即ち水和度の低
いクロメート被膜からなる二層処理被膜は溶接電流が均
一に流れるためか溶接性が優れている。Furthermore, the metal Cr layer is 10mg/w? The two-layer treated coating made of a chromate coating with a high degree of oxidation, that is, a low degree of hydration, has excellent weldability, probably because the welding current flows uniformly.

しかし、その二層被膜被膜量が２０７ｎｇ／イをこえる
と耐食性、塗装後の性能は優れているが電気抵抗溶接に
おいて溶接部にチリの発生が著しくなり、溶接部に欠陥
が発生しやすくなるとともに、ナゲツトの均一生成が充
分に行なわれなくなり、充分な溶接強度が得られなくな
るのでその被膜量は２０彎／一以下に限定することが必
要である。即ち、金属Ｃｒ層が１０彎／ｗｌ−以下、表
面のクロメート被膜層が被膜中の酸素原子に対するｓ原
子の比率が０．１５以下、好ましくは０．１以下、オキ
ソ化度０．９０以上、好ましくは０．９５以上からなり
、金属Ｃｒ層との総和でＣｒ換算量で２０ｍｇ／イ以下
、好ましくは１０ｗ？以下の二層被膜をＮｉメツキ層表
面にクロメート処理被膜として構成することにより、溶
接部にチリ現象による溶接欠陥がなく、均一なナゲツト
が形成された充分な溶接強度を有する良好な溶接が可能
であるとともに、又塗装後の性能が塗膜下での腐食水溶
液によるクロメート被膜の溶出によつて劣化しない、著
しく優れた容器用鋼板が得られる。However, if the amount of the double-layer coating exceeds 207 ng/A, although the corrosion resistance and performance after painting are excellent, the occurrence of dust in the welded area during electric resistance welding becomes significant, and defects are likely to occur in the welded area. Since nuggets are not formed uniformly enough and sufficient welding strength cannot be obtained, it is necessary to limit the coating amount to less than 20 curvature/1. That is, the metal Cr layer has a ratio of 10 curvature/wl or less, the chromate coating layer on the surface has a ratio of s atoms to oxygen atoms in the coating of 0.15 or less, preferably 0.1 or less, and the degree of oxidation is 0.90 or more. It preferably consists of 0.95 or more, and the total amount with the metal Cr layer is 20 mg/I or less in terms of Cr, preferably 10 W? By configuring the following two-layer coating as a chromate-treated coating on the surface of the Ni plating layer, it is possible to perform good welding with sufficient welding strength with uniform nuggets formed and without welding defects due to dust phenomenon in the welded area. At the same time, it is possible to obtain a steel sheet for containers which has extremely excellent performance after painting and whose performance does not deteriorate due to the elution of the chromate film by the corrosive aqueous solution under the paint film.

このため、本発明による容器用鋼板は製缶用素材として
、好適な性能を有し、電気抵抗溶接法による製缶方式に
よつてトラブルを起こすことがなく、またコスト的にも
有利である。次に、本発明の実施例について説明する。Therefore, the steel sheet for containers according to the present invention has suitable performance as a material for can making, does not cause any trouble when making cans by electric resistance welding, and is advantageous in terms of cost. Next, examples of the present invention will be described.

ブリキ用冷延鋼板（テンパーグレードＴ５）に、通常実
施されている慣用的なメツキ前処理（脱脂、酸洗）を行
なつて、電気メツキ法によりＮｉメツキを施してから、
該表面に本発明の陰極電解処理及び高温水処理を施した
。A cold-rolled steel sheet for tinplate (temper grade T5) is subjected to conventional plating pretreatment (degreasing, pickling), and then Ni plating is applied using the electroplating method.
The surface was subjected to the cathodic electrolytic treatment and high temperature water treatment of the present invention.

Claims (1)

【特許請求の範囲】 １ 鋼板の表面に厚さ０．０１〜０．３０μのＮｉメッ
キ層、その表面に被膜量１０ｍｇ／ｍ＾２以下の金属ク
ロム層、さらにその表面にクロメート被膜層を設けると
ともに、該クロメート被膜層の被膜量がＣｒ換算量で金
属クロム層との総和で２０ｍｇ／ｍ＾２以下からなり、
かつ該クロメート被膜中の酸素原子に対するＳ原子の比
率を分光分析スペクトル測定法によるピーク強度比率で
表わして０．１５以下で、Ｃｒ−ＯＨ系オール結合に対
するＣｒ−Ｏ系オキソ系結合の比率を分光分析スペクト
ル測定法によるピーク強度比率で表わして該クロメート
被膜の表面で０．９０以上からなることを特徴とする溶
接性と塗装後の耐食性がすぐれた容器用鋼板。 ２ 鋼板の表面に厚さ０．０１〜０．３０μのＮｉメッ
キを施し、続いてＳＯ＿４＾−＾２／Ｃｒ＾＋＾６の重
量比が１／４０以下からなるＳＯ＿４＾−＾２を含有す
るクロム酸水溶液中で電流密度７．５Ａ／ｄｍ＾２をこ
え２５Ａ／ｄｍ＾２以下でかつ電気量２．５クーロン／
ｄｍ＾２以上で陰極電解処理を行ない、金属Ｃｒ量１０
ｍｇ／ｍ＾２以下でかつ該表面のクロメート被膜量がＣ
ｒ換算量で金属クロム層との総和で２０ｍｇ／ｍ＾２以
下に構成すると共に、直ちにあるいは水洗処理して温度
６５〜１００℃でｐＨ４〜１０の高温水で０．３〜１０
秒間高温水洗処理して、クロメート被膜中の酸素原子に
対するＳ原子の比率を分光分析スペクトル測定法による
ピーク強度比率で表わして０．１５以下でかつ該被膜表
面でのＣｒ−ＯＨ系オール結合に対するＣｒ−Ｏ系オキ
ソ結合の比率を分光分析スペクトル測定法によるピーク
強度比率で表わして０．９０以上のクロメート被膜を形
成することを特徴とする溶接性と塗装後の耐食性がすぐ
れた容器用クロメーユ被膜鋼板の製造法。[Claims] 1. A Ni plating layer with a thickness of 0.01 to 0.30μ on the surface of a steel plate, a metallic chromium layer with a coating amount of 10 mg/m^2 or less on the surface, and a chromate coating layer on the surface. In addition, the coating amount of the chromate coating layer is 20 mg/m^2 or less in terms of Cr amount in total with the metal chromium layer,
The ratio of S atoms to oxygen atoms in the chromate film is 0.15 or less expressed as a peak intensity ratio by spectroscopic analysis, and the ratio of Cr-O oxo bonds to Cr-OH all bonds is determined by spectroscopy. A steel plate for containers having excellent weldability and corrosion resistance after painting, characterized in that the peak intensity ratio on the surface of the chromate film is 0.90 or more as measured by analytical spectroscopy. 2 Ni plating with a thickness of 0.01 to 0.30μ is applied to the surface of the steel plate, followed by SO_4^-^2 containing SO_4^-^2 with a weight ratio of SO_4^-^2/Cr^+^6 of 1/40 or less. In a chromic acid aqueous solution, the current density is more than 7.5 A/dm^2 and less than 25 A/dm^2, and the amount of electricity is 2.5 coulombs/dm^2.
Cathodic electrolytic treatment is performed at dm^2 or more, and the amount of metallic Cr is 10
mg/m^2 or less and the amount of chromate coating on the surface is C
In terms of r equivalent amount, the total amount with the metal chromium layer is 20 mg/m^2 or less, and it is 0.3-10 with high temperature water of 65-100℃ and pH 4-10 immediately or after washing with water.
After washing with high temperature water for seconds, the ratio of S atoms to oxygen atoms in the chromate film, expressed as a peak intensity ratio by spectroscopic analysis, is 0.15 or less, and the Cr-OH-based all bonds on the surface of the chromate film are 0.15 or less. A chromeil coated steel sheet for containers with excellent weldability and corrosion resistance after painting, characterized by forming a chromate film with a ratio of -O-based oxo bonds expressed as a peak intensity ratio measured by spectroscopic analysis and spectroscopy of 0.90 or more. manufacturing method.