JP7381864B2 - Zn-Al-Mg hot-dipped steel sheet - Google Patents
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- 238000007747 plating Methods 0.000 claims description 149
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- 229910052761 rare earth metal Inorganic materials 0.000 claims description 7
- 229910052787 antimony Inorganic materials 0.000 claims description 5
- 229910052796 boron Inorganic materials 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 229910052745 lead Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
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- 229910001335 Galvanized steel Inorganic materials 0.000 description 13
- 239000008397 galvanized steel Substances 0.000 description 13
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- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
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Description
本発明は、Zn-Al-Mg系溶融めっき鋼板に関する。 The present invention relates to a Zn-Al-Mg hot-dip galvanized steel sheet.
溶融亜鉛めっき鋼板に比べて高い耐食性を有するZn-Al-Mg系溶融めっき鋼板は、建材、家電、自動車分野等種々の製造業において広く使用されており、近年、その使用量が増加している。 Zn-Al-Mg hot-dip galvanized steel sheets, which have higher corrosion resistance than hot-dip galvanized steel sheets, are widely used in various manufacturing industries such as building materials, home appliances, and automobiles, and their usage has been increasing in recent years. .
ところで、溶融めっき鋼板の溶融めっき層の表面に、文字、模様、デザイン画などを現すことを目的として、溶融めっき層に印刷や塗装などの工程を施すことにより、文字、模様、デザイン画などを溶融めっき層の表面に現す場合がある。 By the way, for the purpose of making letters, patterns, designs, etc. appear on the surface of the hot-dip coating layer of a hot-dip-coated steel plate, by applying processes such as printing and painting to the hot-dip coating layer, letters, patterns, designs, etc. can be printed on the surface of the hot-dip coating layer. It may appear on the surface of the hot-dip plating layer.
しかし、溶融めっき層に印刷や塗装などの工程を行うと、文字やデザイン等を施すためのコストや時間が増大する問題がある。更に、印刷や塗装によって文字やデザイン等をめっき層の表面に現す場合は、需要者から高い支持を得ている金属光沢外観が失われるだけでなく、塗膜自体の経時劣化や塗膜の密着性の経時劣化の問題から、耐久性が劣り、時間とともに文字やデザイン等が消失してしまう恐れがある。また、インクをスタンプすることで文字やデザイン等をめっき層の表面に現す場合は、コストや時間は比較的抑えられるものの、インクによって、溶融めっき層の耐食性が低下する懸念がある。更に、溶融めっき層の研削によって意匠等を現す場合は、意匠等の耐久性は優れるものの、研削箇所の溶融めっき層の厚みが大幅に減少することから耐食性低下が必然であり、めっき特性の低下が懸念される。 However, when processes such as printing and painting are performed on the hot-dip plating layer, there is a problem in that the cost and time required to apply letters, designs, etc. increase. Furthermore, when characters or designs are displayed on the surface of the plating layer by printing or painting, not only does the metallic luster appearance that is highly popular among customers be lost, but also the paint film itself deteriorates over time and the adhesion of the paint film deteriorates. Due to the problem of physical deterioration over time, durability is poor, and there is a risk that letters, designs, etc. may disappear over time. In addition, when stamping ink to display letters, designs, etc. on the surface of the plating layer, costs and time are relatively reduced, but there is a concern that the ink may reduce the corrosion resistance of the hot-dip plating layer. Furthermore, when a design is created by grinding a hot-dip plating layer, although the durability of the design is excellent, the thickness of the hot-dip plating layer at the grinding point is significantly reduced, which inevitably leads to a decrease in corrosion resistance and a decrease in plating properties. There are concerns.
下記特許文献に示されるように、Zn-Al-Mg系溶融めっき鋼板に対する様々な技術が開発されているが、めっき層の表面に文字やデザイン等を現した場合にその耐久性を向上させる技術は知られていない。 As shown in the following patent documents, various technologies have been developed for Zn-Al-Mg hot-dip galvanized steel sheets, but there is a technology that improves the durability when letters, designs, etc. appear on the surface of the plating layer. is not known.
Zn-Al-Mg系溶融めっき鋼板に関し、Zn-Al-Mg系溶融めっき鋼板にみられる梨地状のめっき外観をより美麗とすることを目的とする従来技術は存在する。
例えば、特許文献1は、キメが細かく、かつ平滑な光沢部が多い梨地状の外観を有するZn-Al-Mg系溶融めっき鋼板、すなわち、単位面積当たりの白色部の個数が多く、そして、光沢部の面積の割合が大きいという良好な梨地状の外観を有するZn-Al-Mg系溶融めっき鋼板が記載されている。また、特許文献1においては、好ましくない梨地の状態を、不定形な白色部と円形状の光沢部とが混在して表面に点在した表面外観を呈している状態であることが記載されている。
また、特許文献4は、Al/MgZn2/Znの三元共晶組織を微細化させることで、全体的にめっき層の光沢度が増し、外観均一性が向上した高耐食性溶融亜鉛めっき鋼板が記載されている。
しかしながら、めっき層の表面に文字等を現した場合に、その耐久性を向上させ、かつ、耐食性を低下させないようにする技術は、従来から知られていなかった。
Regarding Zn-Al-Mg hot-dip plated steel sheets, there is a conventional technique aimed at making the satin-like plating appearance seen in Zn-Al-Mg hot-dip plated steel sheets more beautiful.
For example, Patent Document 1 discloses a Zn-Al-Mg hot-dip galvanized steel sheet having a fine texture and a satin-like appearance with many smooth glossy areas, that is, a large number of white areas per unit area, and a glossy surface. A Zn-Al-Mg hot-dip galvanized steel sheet is described that has a good satin-like appearance with a large area ratio. Further, Patent Document 1 describes that the unfavorable satin finish state is a state in which irregular white parts and circular glossy parts coexist and exhibit a surface appearance dotted on the surface. There is.
Furthermore, Patent Document 4 discloses a highly corrosion-resistant hot-dip galvanized steel sheet in which the overall gloss of the plating layer is increased and the appearance uniformity is improved by refining the ternary eutectic structure of Al/MgZn 2 /Zn. Are listed.
However, a technique for improving the durability and preventing deterioration of corrosion resistance when characters or the like are displayed on the surface of a plating layer has not been known so far.
本発明は、上記事情に鑑みてなされたものであり、めっき層の表面に文字やデザイン等を現すことができ、それらの耐久性に優れ、また、耐食性にも優れた溶融めっき鋼板を提供することを課題とする。 The present invention has been made in view of the above circumstances, and provides a hot-dip plated steel sheet that can display letters, designs, etc. on the surface of the plated layer, has excellent durability, and is also excellent in corrosion resistance. That is the issue.
本発明の要旨は以下の通りである。
[1] 鋼板と、
前記鋼板の表面に形成された溶融めっき層と、
を備え、
前記溶融めっき層は、
平均組成で、Al:4質量%以上25質量%未満、Mg:0質量%以上10質量%未満を含有し、残部がZnおよび不純物を含み、
金属組織として、樹枝晶状のAl相と、Al/Zn/MgZn2の三元共晶組織とを含み、
前記溶融めっき層は、第一領域と第二領域とを含み、
前記第一領域および前記第二領域にはそれぞれ、複数の前記樹枝晶状のAl相が含まれ、
前記第一領域は、前記溶融めっき層の表面における前記Al相の平均の長さが、200μm以上の領域であり、
前記第二領域は、前記溶融めっき層の表面における前記Al相の平均の長さが、200μm未満の領域であり、
前記第一領域または前記第二領域が、直線部、曲線部、図形、数字、記号、模様若しくは文字のいずれか1種またはこれらのうちの2種以上を組合せた意図的な形状である、ことを特徴とするZn-Al-Mg系溶融めっき鋼板。
[2] 前記溶融めっき層が、更に、平均組成で、Si:0.0001~2質量%を含有する、[1]に記載のZn-Al-Mg系溶融めっき鋼板。
[3] 前記溶融めっき層が、更に、平均組成で、Ni、Ti、Zr、Srのいずれか1種または2種以上を、合計で0.0001~2質量%含有する、[1]または[2]に記載のZn-Al-Mg系溶融めっき鋼板。
[4] 前記溶融めっき層が、更に、平均組成で、Sb、Pb、Sn、Ca、Co、Mn、P、B、Bi、Cr、Sc、Y、REM、Hfのいずれか1種または2種以上を、合計で0.0001~2質量%含有する、[1]乃至[3]の何れか一項に記載のZn-Al-Mg系溶融めっき鋼板。
[5] 前記溶融めっき層の付着量が前記鋼板両面合計で30~600g/m2である、[1]乃至[4]の何れか一項に記載のZn-Al-Mg系溶融めっき鋼板。
The gist of the invention is as follows.
[1] Steel plate and
a hot-dip plating layer formed on the surface of the steel plate;
Equipped with
The hot-dip plating layer is
The average composition contains Al: 4% by mass or more and less than 25% by mass, Mg: 0% by mass or more and less than 10% by mass, and the balance contains Zn and impurities,
The metal structure includes a dendritic Al phase and a ternary eutectic structure of Al/Zn/ MgZn2 ,
The hot-dip plating layer includes a first region and a second region,
The first region and the second region each include a plurality of the dendrite-like Al phases,
The first region is a region where the average length of the Al phase on the surface of the hot-dip plating layer is 200 μm or more,
The second region is a region where the average length of the Al phase on the surface of the hot-dip plating layer is less than 200 μm,
The first region or the second region has an intentional shape consisting of any one of a straight part, a curved part, a figure, a number, a symbol, a pattern, or a character, or a combination of two or more of these. A Zn-Al-Mg hot-dip plated steel sheet .
[ 2 ] The Zn-Al-Mg hot-dip plated steel sheet according to [1] , wherein the hot-dip plated layer further contains Si: 0.0001 to 2% by mass in average composition.
[ 3 ] The hot-dip plating layer further contains, in average composition, any one or two or more of Ni, Ti, Zr, and Sr in a total of 0.0001 to 2% by mass, [1] or [ 2] Zn-Al-Mg hot-dip plated steel sheet.
[ 4 ] The hot-dip plating layer further has an average composition of one or two of Sb, Pb, Sn, Ca, Co, Mn, P, B, Bi, Cr, Sc, Y, REM, and Hf. The Zn-Al-Mg hot-dipped steel sheet according to any one of [1] to [ 3 ], which contains the above in a total of 0.0001 to 2% by mass.
[ 5 ] The Zn-Al-Mg hot-dip plated steel sheet according to any one of [1] to [ 4 ], wherein the amount of the hot-dip plated layer deposited on both sides of the steel sheet is 30 to 600 g/m 2 in total.
本発明によれば、溶融めっき層の表面に文字やデザイン等を現した場合に、それらの耐久性に優れ、また、耐食性にも優れた溶融めっき鋼板を提供できる。 According to the present invention, it is possible to provide a hot-dip plated steel sheet that has excellent durability and corrosion resistance when letters, designs, etc. are displayed on the surface of the hot-dip plated layer.
以下、本発明の実施形態について説明する。
本実施形態のZn-Al-Mg系溶融めっき鋼板は、鋼板と、鋼板の表面に形成された溶融めっき層とを備え、溶融めっき層は、平均組成で、Al:4質量%以上25質量%未満、Mg:0質量%以上10質量%未満を含有し、残部がZnおよび不純物を含み、金属組織として、Al相と、Al/Zn/MgZn2の三元共晶組織とを含む。溶融めっき層は、第一領域と第二領域とからなる。第一領域は、溶融めっき層の表面におけるAl相の平均の長さが、200μm以上の領域であり、第二領域は、溶融めっき層の表面におけるAl相の平均の長さが、200μm未満の領域である。そして、第一領域または第二領域が、所定の形状となるように配置されている。
本実施形態のZn-Al-Mg系溶融めっき鋼板は、好ましくは、第一領域または第二領域が、直線部、曲線部、図形、数字、記号、模様若しくは文字のいずれか1種またはこれらのうちの2種以上を組合せた形状となるように配置されている。第一領域または第二領域は、意図的に形成されたものである。
Embodiments of the present invention will be described below.
The Zn-Al-Mg hot-dip plated steel sheet of the present embodiment includes a steel plate and a hot-dip coating layer formed on the surface of the steel plate, and the hot-dip coating layer has an average composition of Al: 4% by mass or more and 25% by mass. Mg: 0% by mass or more and less than 10% by mass, the balance contains Zn and impurities, and the metal structure includes an Al phase and a ternary eutectic structure of Al/Zn/MgZn 2 . The hot-dip plating layer consists of a first region and a second region. The first region is a region where the average length of the Al phase on the surface of the hot-dip plating layer is 200 μm or more, and the second region is a region where the average length of the Al phase on the surface of the hot-dip plating layer is less than 200 μm. It is an area. The first region or the second region is arranged to have a predetermined shape.
In the Zn-Al-Mg hot-dip galvanized steel sheet of the present embodiment, preferably, the first region or the second region includes any one of a straight portion, a curved portion, a figure, a number, a symbol, a pattern, or a character, or any one of these. They are arranged in a shape that is a combination of two or more of them. The first region or the second region is intentionally formed.
ここで、Al相とは、Al/Zn/MgZn2の三元共晶組織の素地中に明瞭な境界をもって島状に見える相であり、これは例えばAl-Zn-Mgの三元系平衡状態図における高温での「Al″相」(Znを固溶するAl固溶体であり、少量のMgを含む)に相当し、三元共晶組織中のAlとは区別される。以下、本実施形態では、〔Al相〕と表記する。 Here, the Al phase is a phase that appears like an island with clear boundaries in the matrix of the ternary eutectic structure of Al/Zn/ MgZn2 , and this is, for example, a phase in the ternary equilibrium state of Al-Zn-Mg. This corresponds to the "Al" phase (an Al solid solution containing Zn and a small amount of Mg) at high temperature in the figure, and is distinguished from Al in the ternary eutectic structure. Hereinafter, in this embodiment, it will be referred to as [Al phase].
<鋼板>
溶融めっき層の下地として用いる鋼板の材質は、特に制限されない。詳細は後述するが、鋼板としては、一般鋼などを用いることができ、Alキルド鋼や一部の高合金鋼を用いることも可能である。また、鋼板の形状も特に制限されない。鋼板に対して後述する溶融めっき法を適用することで、本実施形態に係る溶融めっき層が形成される。
<Steel plate>
The material of the steel plate used as the base of the hot-dip plating layer is not particularly limited. Although details will be described later, general steel or the like can be used as the steel plate, and Al-killed steel or some high-alloy steel can also be used. Further, the shape of the steel plate is not particularly limited either. The hot-dip plating layer according to this embodiment is formed by applying the hot-dip plating method described below to the steel plate.
<溶融めっき層>
(化学成分)
次に、溶融めっき層の化学成分について説明する。
溶融めっき層は、平均組成で、Al:4質量%以上25質量%未満、Mg:0質量%以上10質量%未満を含有し、残部としてZnおよび不純物を含む。溶融めっき層は、好ましくは、平均組成で、Al:4~22質量%、Mg:1~10質量%を含有し、残部としてZnおよび不純物からなる。
溶融めっき層は、平均組成で、Si:0.0001~2質量%を含有してもよい。溶融めっき層は、平均組成で、Ni、Ti、Zr、Srのいずれか1種または2種以上を合計で、0.0001~2質量%含有してもよい。溶融めっき層は、平均組成で、Sb、Pb、Sn、Ca、Co、Mn、P、B、Bi、Cr、Sc、Y、REM、Hfのいずれか1種または2種以上を合計で、0.0001~2質量%を含有してもよい。
<Hot-dip plating layer>
(Chemical composition)
Next, the chemical components of the hot-dip plating layer will be explained.
The hot-dip plating layer has an average composition of Al: 4% by mass or more and less than 25% by mass, Mg: 0% by mass or more and less than 10% by mass, and the balance contains Zn and impurities. The hot-dip plating layer preferably contains, in average composition, Al: 4 to 22% by mass, Mg: 1 to 10% by mass, and the remainder consists of Zn and impurities.
The hot-dip plating layer may contain Si: 0.0001 to 2% by mass in average composition. The hot-dip plating layer may contain a total of 0.0001 to 2% by mass of any one or more of Ni, Ti, Zr, and Sr in an average composition. The hot-dip plating layer has an average composition of one or more of Sb, Pb, Sn, Ca, Co, Mn, P, B, Bi, Cr, Sc, Y, REM, and Hf in total of 0. It may contain .0001 to 2% by mass.
[Al:4質量%以上25質量%未満]
溶融めっき層におけるAlの含有量は、平均組成で4質量%以上25質量%未満である。Alは、耐食性を確保するために必要な元素である。溶融めっき層中のAlの含有量が4質量%未満では、耐食性を向上させる効果が不十分であるため、また、〔Al相〕が十分に形成されなくなるため意匠性の確保にも好ましくなく、25質量%以上になると〔Al相〕が過剰に形成されるため意匠性の確保に好ましくない。溶融めっき層におけるAlの含有量は、耐食性の観点から、5~22質量%であってもよく、5~18質量%であってもよく、6~16質量%であってもよい。
[Al: 4% by mass or more and less than 25% by mass]
The average content of Al in the hot-dip plating layer is 4% by mass or more and less than 25% by mass. Al is an element necessary to ensure corrosion resistance. If the content of Al in the hot-dip plating layer is less than 4% by mass, the effect of improving corrosion resistance will be insufficient, and the [Al phase] will not be sufficiently formed, which is not preferable for ensuring design properties. If it exceeds 25% by mass, an excessive amount of [Al phase] will be formed, which is not preferable for ensuring good design. From the viewpoint of corrosion resistance, the content of Al in the hot-dip plating layer may be 5 to 22% by mass, 5 to 18% by mass, or 6 to 16% by mass.
[Mg:0質量%以上10質量%未満]
溶融めっき層におけるMgの含有量は、平均組成で0質量%以上10質量%未満であり、好ましくは1質量%以上10質量%未満である。Mgは、耐食性を向上させるために添加してもよい。溶融めっき層中のMgの含有量が1質量%以上になると、耐食性を向上させる効果がより十分となるので好ましい。また、Mgが10質量%以上になるとMg化合物が晶出するため意匠性の確保に好ましくなく、また、めっき浴でのドロス発生が著しくなり、安定的に溶融めっき鋼板を製造するのが困難となるため好ましくない。耐食性とドロス発生の抑制とのバランスの観点から、溶融めっき層におけるMgの含有量は、1.5~6質量%としてもよく、2~5質量%としてもよい。
[Mg: 0% by mass or more and less than 10% by mass]
The average composition of Mg content in the hot-dip plating layer is 0% by mass or more and less than 10% by mass, preferably 1% by mass or more and less than 10% by mass. Mg may be added to improve corrosion resistance. It is preferable that the content of Mg in the hot-dip plating layer is 1% by mass or more because the effect of improving corrosion resistance becomes more sufficient. Furthermore, if the Mg content exceeds 10% by mass, Mg compounds will crystallize, which is unfavorable for ensuring design quality, and dross generation in the plating bath will become significant, making it difficult to stably produce hot-dip galvanized steel sheets. This is not desirable. From the viewpoint of the balance between corrosion resistance and suppression of dross generation, the content of Mg in the hot-dip plating layer may be 1.5 to 6% by mass, or may be 2 to 5% by mass.
溶融めっき層は、Siを0.0001~2質量%の範囲で含有してもよい。Siは、溶融めっき層の密着性を向上させるのに有効な元素である。
Siを溶融めっき層に0.0001質量%以上含有させることで密着性を向上させる効果が発現するため、Siを0.0001質量%以上含有させることが好ましい。
一方、2質量%を超えて含有させてもめっき密着性を向上させる効果が飽和するため、溶融めっき層にSiを含有させる場合であっても、Siの含有量は2質量%以下とする。
めっき密着性の観点からは、溶融めっき層におけるSiの含有量は0.0010~1質量%としてもよく、0.0100~0.8質量%としてもよい。
The hot-dip plating layer may contain Si in a range of 0.0001 to 2% by mass. Si is an effective element for improving the adhesion of the hot-dip plating layer.
By containing 0.0001% by mass or more of Si in the hot-dip plating layer, the effect of improving adhesion is exhibited, so it is preferable to contain 0.0001% by mass or more of Si.
On the other hand, even if the content exceeds 2% by mass, the effect of improving plating adhesion is saturated, so even if the hot-dip plating layer contains Si, the content of Si should be 2% by mass or less.
From the viewpoint of plating adhesion, the content of Si in the hot-dip plating layer may be 0.0010 to 1% by mass, or 0.0100 to 0.8% by mass.
溶融めっき層中には、平均組成で、Ni、Ti、Zr、Srのいずれか1種または2種以上を合計で、0.0001~2質量%含有してもよい。これらの元素を含む金属間化合物は、初晶Al相の晶出核として作用し、〔Al/MgZn2/Znの三元共晶組織〕をより微細、均一にして、溶融めっき層の外観や平滑性を向上させる。溶融めっき層におけるこれらの元素の含有量が0.0001質量%未満では、凝固組織を微細均一にする効果が不十分になるため好ましくない。また、溶融めっき層におけるこれらの元素の含有量が2質量%を超えると、〔Al/MgZn2/Znの三元共晶組織〕を微細化させる効果が飽和し、かつ、溶融めっき層の表面粗度が大きくなり外観が悪くなるため、好ましくない。
特に溶融めっき層の外観向上を目的として上述の元素を添加する場合、上述の元素の含有量は0.001~0.5質量%が好ましく、0.001~0.05質量%がより好ましく、さらに好ましくは0.002~0.01質量%である。
The average composition of the hot-dip plated layer may contain one or more of Ni, Ti, Zr, and Sr in a total amount of 0.0001 to 2% by mass. Intermetallic compounds containing these elements act as crystallization nuclei for the primary Al phase, making the [ternary eutectic structure of Al/MgZn 2 /Zn] finer and more uniform, and improving the appearance and appearance of the hot-dip coating layer. Improve smoothness. If the content of these elements in the hot-dip plating layer is less than 0.0001% by mass, the effect of making the solidified structure fine and uniform becomes insufficient, which is not preferable. Furthermore, when the content of these elements in the hot-dip coating layer exceeds 2% by mass, the effect of refining the [ternary eutectic structure of Al/MgZn 2 /Zn] is saturated, and the surface of the hot-dip coating layer is This is not preferred because the roughness increases and the appearance deteriorates.
In particular, when adding the above-mentioned elements for the purpose of improving the appearance of the hot-dip plating layer, the content of the above-mentioned elements is preferably 0.001 to 0.5% by mass, more preferably 0.001 to 0.05% by mass, More preferably, it is 0.002 to 0.01% by mass.
溶融めっき層中には、平均組成で、Sb、Pb、Sn、Ca、Co、Mn、P、B、Bi、Cr、Sc、Y、REM、Hfの1種又は2種以上を合計で0.0001~2質量%を含有してもよい。溶融めっき層がこれらの元素を含有することで、さらに耐食性を改善することができる。
なお、REMは、周期律表における原子番号57~71の希土類元素の1種または2種以上を指す。
The average composition of the hot-dip plating layer is one or more of Sb, Pb, Sn, Ca, Co, Mn, P, B, Bi, Cr, Sc, Y, REM, and Hf in a total of 0. 0001 to 2% by mass may be contained. By containing these elements in the hot-dip plating layer, corrosion resistance can be further improved.
Note that REM refers to one or more rare earth elements with atomic numbers 57 to 71 in the periodic table.
溶融めっき層の化学成分の残部は、亜鉛及び不純物である。不純物には、亜鉛ほかの地金中に不可避的に含まれるもの、めっき浴中で、鋼が溶解することによって含まれるものがある。また、めっきを溶解する際にめっき層と鋼の界面に生成する合金層由来のFeが測定されることもある。 The remainder of the chemical components of the hot dip plated layer are zinc and impurities. Impurities include those that are unavoidably included in base metals such as zinc, and those that are included when steel is melted in a plating bath. Furthermore, Fe derived from an alloy layer generated at the interface between the plating layer and the steel when the plating is melted is sometimes measured.
なお、溶融めっき層の平均組成は、次のような方法で測定できる。まず、めっきを浸食しない塗膜剥離剤(例えば、三彩化工社製ネオリバーSP-751)で表層塗膜を除去した後に、インヒビター(例えば、スギムラ化学工業社製ヒビロン)入りの塩酸で溶融めっき層を溶解し、得られた溶液を誘導結合プラズマ(ICP)発光分光分析に供することで求めることができる。また、表層塗膜を有しない場合は、表層塗膜の除去作業を省略できる。 Note that the average composition of the hot-dip plating layer can be measured by the following method. First, the surface coating film is removed with a paint film remover that does not corrode the plating (for example, Neoliver SP-751 manufactured by Sansai Kako Co., Ltd.), and then the hot-dip plating layer is removed with hydrochloric acid containing an inhibitor (for example, Hibiron manufactured by Sugimura Kagaku Kogyo Co., Ltd.). It can be determined by dissolving and subjecting the resulting solution to inductively coupled plasma (ICP) emission spectroscopic analysis. In addition, when there is no surface layer coating, the removal work of the surface layer coating can be omitted.
(金属組織)
次に、溶融めっき層の金属組織について説明する。本実施形態に係る溶融めっき層は、金属組織として〔Al相〕と、〔Al/Zn/MgZn2の三元共晶組織〕とを含んでいる。
具体的には、本実施形態に係る溶融めっき層は、〔Al/Zn/MgZn2の三元共晶組織〕の素地中に、〔Al相〕が包含された形態を有している。
更に、〔Al/Zn/MgZn2の三元共晶組織〕の素地中に、〔MgZn2相〕や〔Zn相〕が含まれていてもよい。
また、Siを添加した場合には、〔Al/Zn/MgZn2の三元共晶組織〕の素地中に、〔Mg2Si相〕が含まれていてもよい。
(Metal structure)
Next, the metal structure of the hot-dip plating layer will be explained. The hot-dip plating layer according to the present embodiment includes an [Al phase] and a [ternary eutectic structure of Al/Zn/MgZn 2 ] as a metal structure.
Specifically, the hot-dip plating layer according to the present embodiment has a form in which an [Al phase] is included in a matrix of [ternary eutectic structure of Al/Zn/MgZn 2 ] .
Furthermore, [MgZn 2 phase] or [Zn phase] may be contained in the matrix of [ternary eutectic structure of Al/Zn/MgZn 2 ].
Further, when Si is added, [Mg 2 Si phase] may be included in the matrix of [ternary eutectic structure of Al/Zn/MgZn 2 ].
〔Al/Zn/MgZn2の三元共晶組織〕
ここで、〔Al/Zn/MgZn2の三元共晶組織〕とは、Al相と、Zn相と金属間化合物MgZn2相との三元共晶組織であり、この三元共晶組織を形成しているAl相は例えばAl-Zn-Mgの三元系平衡状態図における高温での「Al″相」(Znを固溶するAl固溶体であり、少量のMgを含む)に相当する。
この高温でのAl″相は、常温では通常は微細なAl相と微細なZn相とに分離して現れる。該三元共晶組織中のZn相は少量のAlを固溶し、場合によってはさらに少量のMgを固溶したZn固溶体である。該三元共晶組織中のMgZn2相は、Zn-Mgの二元系平衡状態図のZn:約84質量%の付近に存在する金属間化合物相である。
状態図で見る限りそれぞれの相にはその他の添加元素を固溶していないか、固溶していても極微量であると考えられる。しかしながら、その量は通常の分析では明確に区別できないため、この3つの相からなる三元共晶組織を本明細書では〔Al/Zn/MgZn2の三元共晶組織〕と表す。
[Ternary eutectic structure of Al/Zn/MgZn 2 ]
Here, [ternary eutectic structure of Al/Zn/MgZn 2 ] is a ternary eutectic structure of an Al phase, a Zn phase, and an intermetallic compound MgZn 2 phase; The formed Al phase corresponds to, for example, the "Al" phase (which is an Al solid solution containing Zn and contains a small amount of Mg) at a high temperature in the ternary equilibrium phase diagram of Al-Zn-Mg.
This Al'' phase at high temperature normally appears separated into a fine Al phase and a fine Zn phase at room temperature.The Zn phase in the ternary eutectic structure contains a small amount of Al as a solid solution, and in some cases is a Zn solid solution containing a small amount of Mg.The MgZn two phase in the ternary eutectic structure is a metal that exists near Zn: about 84% by mass in the Zn-Mg binary equilibrium phase diagram. It is an intermediate compound phase.
As far as we can see from the phase diagram, it is thought that other additive elements are not solidly dissolved in each phase, or even if they are solidly dissolved, the amount is extremely small. However, since the amounts cannot be clearly distinguished by ordinary analysis, the ternary eutectic structure consisting of these three phases is herein referred to as [ternary eutectic structure of Al/Zn/MgZn 2 ].
〔Al相〕
〔Al相〕とは、前記の三元共晶組織の素地中に明瞭な境界をもって島状に見える相であり、これは例えばAl-Zn-Mgの三元系平衡状態図における高温での「Al″相」(Znを固溶するAl固溶体であり、少量のMgを含む)に相当する。この高温でのAl″相は、めっき浴のAlやMg濃度に応じて、固溶するZn量やMg量が相違する。この高温でのAl″相は、常温では通常は微細なAl相と微細なZn相とに分離するが、常温で見られる島状の形状は高温でのAl″相の形状に起因すると考えられる。
状態図で見る限りこの相にはその他の添加元素を固溶していないか、固溶していても極微量であると考えられる。しかしながら、通常の分析では明確に区別できないため、この高温でのAl″相に由来し且つ形状的にはAl″相の形状に起因する相を本明細書では〔Al相〕と呼ぶ。
〔Al相〕は前記の三元共晶組織を形成しているAl相とは顕微鏡観察において明瞭に区別できる。
本実施形態では、後述するように、〔Al相〕の平均の長さを、第一領域では200μm以上とし、第2領域では200μm未満とする。
[Al phase]
[Al phase] is a phase that appears like an island with clear boundaries in the matrix of the above-mentioned ternary eutectic structure, and this is, for example, a phase in the ternary equilibrium phase diagram of Al-Zn-Mg that This corresponds to the "Al" phase (which is an Al solid solution containing Zn and contains a small amount of Mg). The amount of dissolved Zn and Mg in this Al'' phase at high temperature differs depending on the Al and Mg concentrations in the plating bath.The Al'' phase at high temperature is normally different from the fine Al phase at room temperature. Although it separates into a fine Zn phase, the island-like shape seen at room temperature is thought to be due to the shape of the Al'' phase at high temperatures.
As far as we can see from the phase diagram, it is considered that other additive elements are not dissolved in this phase, or even if they are dissolved, the amount is extremely small. However, since it cannot be clearly distinguished by ordinary analysis, the phase that is derived from the Al'' phase at high temperatures and whose shape is due to the shape of the Al'' phase is herein referred to as the [Al phase].
[Al phase] can be clearly distinguished from the Al phase forming the above-mentioned ternary eutectic structure by microscopic observation.
In this embodiment, as described later, the average length of the [Al phase] is 200 μm or more in the first region and less than 200 μm in the second region.
〔Zn相〕
〔Zn相〕とは、前記の三元共晶組織の素地中に明瞭な境界をもって島状に見える相であり、実際には少量のAlや少量のMgを固溶していることがある。状態図で見る限り、この相にはその他の添加元素を固溶していないか、固溶していても極微量であると考えられる。
〔Zn相〕は、前記の三元共晶組織を形成しているZn相とは顕微鏡観察において明瞭に区別できる。本実施形態に係る溶融めっき層には、製造条件により〔Zn相〕が含まれる場合が有るが、〔Zn相〕に起因する耐食性への影響はほとんど見られなかった。そのため、溶融めっき層に〔Zn相〕が含まれても、特に問題は無い。
[Zn phase]
[Zn phase] is a phase that appears like an island with clear boundaries in the matrix of the above-mentioned ternary eutectic structure, and may actually contain a small amount of Al or a small amount of Mg as a solid solution. As far as we can see from the phase diagram, it is thought that this phase does not contain any other additive elements, or even if they do, the amount is extremely small.
[Zn phase] can be clearly distinguished from the Zn phase forming the above-mentioned ternary eutectic structure by microscopic observation. Although the hot-dip plating layer according to the present embodiment may contain a [Zn phase] depending on manufacturing conditions, almost no influence on corrosion resistance due to the [Zn phase] was observed. Therefore, there is no particular problem even if the hot-dip plating layer contains [Zn phase].
〔MgZn2相〕
〔MgZn2相〕とは、前記の三元共晶組織の素地中に明瞭な境界をもって島状に見える相であり、実際には少量のAlを固溶していることがある。状態図で見る限り、この相にはその他の添加元素を固溶していないか、固溶していても極微量であると考えられる。
〔MgZn2相〕と前記の三元共晶組織を形成しているMgZn2相とは、顕微鏡観察において明瞭に区別できる。本実施形態に係る溶融めっき層には、製造条件により〔MgZn2相〕が含まれない場合も有るが、ほとんどの製造条件では溶融めっき層中に含まれる。
[MgZn 2- phase]
[MgZn two- phase] is a phase that appears like an island with clear boundaries in the matrix of the above-mentioned ternary eutectic structure, and may actually contain a small amount of Al in solid solution. As far as we can see from the phase diagram, it is thought that this phase does not contain any other additive elements, or even if they do, the amount is extremely small.
[MgZn two- phase] and the MgZn two- phase forming the above-mentioned ternary eutectic structure can be clearly distinguished by microscopic observation. The hot-dip plating layer according to this embodiment may not contain [MgZn two- phase] depending on the manufacturing conditions, but it is included in the hot-dip plating layer under most manufacturing conditions.
〔Mg2Si相〕
〔Mg2Si相〕とは、Siを添加しためっき層の凝固組織中に、明瞭な境界を持って島状に見える相である。状態図で見る限り、〔Mg2Si相〕にはZn、Al、その他の添加元素は固溶していないか、固溶していても極微量であると考えられる。〔Mg2Si相〕は、溶融めっき層中では顕微鏡観察において明瞭に他の相と区別できる。
[Mg 2 Si phase]
[Mg 2 Si phase] is a phase that appears in the form of islands with clear boundaries in the solidified structure of the plating layer to which Si is added. As far as we can see from the phase diagram, it is thought that Zn, Al, and other additive elements are not dissolved in the [Mg 2 Si phase], or even if they are dissolved, the amount is extremely small. [Mg 2 Si phase] can be clearly distinguished from other phases in the hot-dip plating layer by microscopic observation.
本実施形態の溶融めっき層は、鋼板がめっき浴に浸漬された後に引き上げられ、その後、鋼板表面に付着した溶融金属が凝固することにより形成される。このとき、最初に、〔Al相〕が形成され、その後、溶融金属の温度低下に伴い、〔Al/Zn/MgZn2の三元共晶組織〕が形成される。
溶融めっき層の化学成分(つまり、めっき浴の化学成分)によっては、〔Al/Zn/MgZn2の三元共晶組織〕の素地中に、〔Mg2Si相〕、〔MgZn2相〕または〔Zn相〕が形成される場合もある。
The hot-dip plating layer of this embodiment is formed by immersing a steel plate in a plating bath and then pulling it up, and then solidifying the molten metal adhering to the surface of the steel plate. At this time, [Al phase] is first formed, and then as the temperature of the molten metal decreases, [ternary eutectic structure of Al/Zn/MgZn 2 ] is formed.
Depending on the chemical composition of the hot-dip plating layer (that is, the chemical composition of the plating bath), [Mg 2 Si phase], [MgZn 2 phase], or [Zn phase] may be formed.
(第一領域及び第二領域)
次に、溶融めっき層の第一領域及び第二領域について説明する。本実施形態に係る溶融めっき層(溶融めっき層の表面)には、第一領域と第二領域とが存在する。第一領域は、平均長さが長いAl相に起因する金属光沢が観察される。そのため、光沢が線状に認識できる。一方の、第二領域は、平均長さが短いAl相に起因して、金属光沢が点状に認識される。このため、第一領域と第二領域は、肉眼、拡大鏡下または顕微鏡下で識別可能になっている。
(First area and second area)
Next, the first region and the second region of the hot-dip plating layer will be explained. The hot-dip plating layer (the surface of the hot-dip plating layer) according to this embodiment includes a first region and a second region. In the first region, metallic luster due to the Al phase having a long average length is observed. Therefore, the gloss can be perceived as a line. On the other hand, in the second region, dotted metallic luster is recognized due to the Al phase having a short average length. Therefore, the first region and the second region are distinguishable with the naked eye, under a magnifying glass, or under a microscope.
本実施形態では、第一領域が直線部、曲線部等を現すものであってもよく、第二領域が直線部、曲線部等を現すものであってもよい。第一領域が直線部、曲線部等を現すものである場合は、第一領域が所定の形状となるように配置され、それ以外の領域を第二領域とすることができる。また、第二領域が直線部、曲線部等を現すものである場合は、第二領域が所定の形状となるように配置され、それ以外の領域を第一領域とすることができる。第一領域と第二領域の境界は、肉眼、拡大鏡下または顕微鏡下で把握することができる。 In the present embodiment, the first region may represent a straight portion, a curved portion, etc., and the second region may represent a straight portion, a curved portion, etc. When the first region represents a straight line portion, a curved portion, etc., the first region may be arranged to have a predetermined shape, and the other region may be the second region. Further, when the second region represents a straight line portion, a curved portion, etc., the second region can be arranged to have a predetermined shape, and the other region can be used as the first region. The boundary between the first region and the second region can be recognized with the naked eye, under a magnifying glass, or under a microscope.
第一領域が所定の形状となるように配置される場合の第一領域は、肉眼で第一領域の存在を判別可能な程度の大きさに形成されるとよい。この場合の第二領域は、溶融めっき層(溶融めっき層の表面)において第一領域以外の部分を占める領域となり、溶融めっき層の大部分を占めてもよい。また、第二領域内に第一領域が配置されてもよい。具体的には、第一領域は、第二領域内おいて、直線部、曲線部、図形、数字、記号、模様及び文字のいずれか1種またはこれらのうちの2種以上を組合せた形状となるように配置されていてもよい。第一領域の形状を調整することによって、溶融めっき層の表面に、直線部、曲線部、図形、数字、記号、模様及び文字のいずれか1種またはこれらのうちの2種以上を組合せた形状が現される。この形状は人工的に形成された形状であり、自然に形成されたものではない。 When the first region is arranged to have a predetermined shape, the first region is preferably formed to have a size that allows the presence of the first region to be determined with the naked eye. In this case, the second region is a region that occupies a portion of the hot-dip plating layer (the surface of the hot-dip plating layer) other than the first region, and may occupy most of the hot-dip plating layer. Further, the first region may be arranged within the second region. Specifically, the first region has a shape in the second region of any one of straight parts, curved parts, figures, numbers, symbols, patterns, and characters, or a combination of two or more of these. It may be arranged as follows. By adjusting the shape of the first region, the surface of the hot-dip plating layer has a shape of any one of straight parts, curved parts, figures, numbers, symbols, patterns, and letters, or a combination of two or more of these. appears. This shape is an artificially formed shape and is not naturally formed.
一方、第二領域が所定の形状となるように配置される場合の第二領域は、肉眼で第二領域の存在を判別可能な程度の大きさに形成されるとよい。この場合の第一領域は、溶融めっき層(溶融めっき層の表面)において第二領域以外の部分を占める領域となり、溶融めっき層の大部分を占めてもよい。また、第一領域内に第二領域が配置されてもよい。具体的には、第二領域は、第一領域内おいて、直線部、曲線部、図形、数字、記号、模様及び文字のいずれか1種またはこれらのうちの2種以上を組合せた形状となるように配置されていてもよい。第二領域の形状を調整することによって、溶融めっき層の表面に、直線部、曲線部、図形、数字、記号、模様及び文字のいずれか1種またはこれらのうちの2種以上を組合せた形状が現される。この形状は人工的に形成された形状であり、自然に形成されたものではない。 On the other hand, when the second region is arranged to have a predetermined shape, the second region is preferably formed to have a size that allows the presence of the second region to be determined with the naked eye. In this case, the first region occupies a portion of the hot-dip plating layer (the surface of the hot-dip plating layer) other than the second region, and may occupy most of the hot-dip plating layer. Moreover, the second area may be arranged within the first area. Specifically, the second region has a shape in the first region of any one of straight parts, curved parts, figures, numbers, symbols, patterns, and characters, or a combination of two or more of these. It may be arranged as follows. By adjusting the shape of the second region, the surface of the hot-dip plating layer has a shape of any one of straight parts, curved parts, figures, numbers, symbols, patterns, and letters, or a combination of two or more of these. appears. This shape is an artificially formed shape and is not naturally formed.
第一領域と第二領域は、肉眼に限らず、拡大鏡下または顕微鏡下で識別可能であってもよい。具体的には、第一領域または第二領域で構成される直線部等の形状は、50倍以下の視野で識別可能であればよい。50倍以下の視野であれば、第一領域または第二領域で構成される所定の形状は、その表面状態の違いにより、識別可能である。
第一領域または第二領域は、好ましくは20倍以下、さらに好ましくは10倍以下、より好ましくは5倍以下で識別可能である。
The first region and the second region are not limited to being visible to the naked eye, but may be distinguishable under a magnifying glass or a microscope. Specifically, the shape of the straight line portion or the like formed in the first region or the second region may be discernible in a field of view of 50 times or less. With a field of view of 50 times or less, the predetermined shape constituted by the first region or the second region can be identified by the difference in the surface state.
The first region or the second region is preferably distinguishable at 20 times or less, more preferably 10 times or less, more preferably 5 times or less.
第一領域と第二領域は、下記の条件を満たすものである。
(a)第一領域は、溶融めっき層の表面における〔Al相〕の平均長さが200μm以上の領域である。
(b)第二領域は、溶融めっき層の表面における〔Al相〕の平均長さが200μm未満の領域、好ましくは〔Al相〕の大きさが180μm以下の領域、より好ましくは〔Al相〕の大きさが150μm未満の領域である。
The first region and the second region satisfy the following conditions.
(a) The first region is a region in which the average length of the [Al phase] on the surface of the hot-dip plating layer is 200 μm or more.
(b) The second region is a region where the average length of [Al phase] on the surface of the hot-dip plating layer is less than 200 μm, preferably a region where the size of [Al phase] is 180 μm or less, more preferably [Al phase] This is a region where the size of is less than 150 μm.
溶融めっき層には、少なくとも〔Al相〕及び〔Al/Zn/MgZn2の三元共晶組織〕が存在する。溶融めっき層では、〔Al/Zn/MgZn2の三元共晶組織〕の素地中に、〔Al相〕が包含された形態を有する。そして、〔Al相〕は、溶融めっき層の凝固時に比較的早期に析出するものであり、その際の〔Al相〕の形態は樹枝晶状となる。 At least [Al phase] and [ternary eutectic structure of Al/Zn/MgZn 2 ] are present in the hot-dip plating layer. The hot-dip plating layer has a form in which an [Al phase] is included in a matrix of [ternary eutectic structure of Al/Zn/MgZn 2] . The [Al phase] precipitates relatively early during solidification of the hot-dip plating layer, and the form of the [Al phase] at that time becomes dendrite-like.
ここで、第一領域に存在する〔Al相〕の平均長さは、200μm以上になっている。〔Al相〕の平均長さが200μm以上になると、溶融めっき層表面に〔Al相〕の比較的大きな樹枝晶が露出するようになり、周囲に存在する三元共晶組織などに比べて金属光沢であるAl相が長く、また凹凸の明確になることから、全体として線状に視認できるようになる。 Here, the average length of the [Al phase] present in the first region is 200 μm or more. When the average length of the [Al phase] is 200 μm or more, relatively large dendrites of the [Al phase] will be exposed on the surface of the hot-dip plating layer, and the metal structure will be stronger than the surrounding ternary eutectic structure. Since the shiny Al phase is long and the unevenness is clear, the entire surface can be visually recognized as a line.
一方、第二領域に存在する〔Al相〕の平均長さは、200μm未満になっている。〔Al相〕の平均長さが200μm未満になると、溶融めっき層表面に〔Al相〕の比較的小さな樹枝晶が露出するようになり、周囲に存在する三元共晶組織などに比べて金属光沢であるAl相が短く、また凹凸が不明瞭になることから、全体として点状に視認できるようになる。第二領域は、好ましくは〔Al相〕の平均長さが180μm以下の領域であり、より好ましくは〔Al相〕の平均長さが150μm未満の領域である。第一領域のおける〔Al相〕の平均長さと、第二領域における〔Al相〕の平均長さの差が大きくなるほど、第一領域及び第二領域を識別しやすくなるため好ましい。 On the other hand, the average length of the [Al phase] present in the second region is less than 200 μm. When the average length of the [Al phase] is less than 200 μm, relatively small dendrites of the [Al phase] will be exposed on the surface of the hot-dip plating layer, and the metal will be smaller than the surrounding ternary eutectic structure. Since the shiny Al phase is short and the unevenness becomes unclear, the entire surface becomes visible in the form of dots. The second region is preferably a region where the average length of the [Al phase] is 180 μm or less, more preferably a region where the average length of the [Al phase] is less than 150 μm. The larger the difference between the average length of the [Al phase] in the first region and the average length of the [Al phase] in the second region, the easier it is to distinguish between the first region and the second region, which is preferable.
第一領域は、溶融めっき層の凝固時の初期に、〔Al相〕が比較的低い個数密度で生成し、〔Al相〕自体が粗大化することによって形成されるものと推測される。また、第二領域は、溶融めっき層の凝固時の初期に、〔Al相〕が比較的高い個数密度で生成し、〔Al相〕自体が粗大化せず微細のままになることによって形成されるものと推測される。〔Al相〕の大きさを制御するためには、溶融めっき層の凝固時に、溶融金属の冷却速度を制御すればよい。具体的には、〔Al相〕を粗大化させる場合は凝固時の冷却速度を遅くし、〔Al相〕を微細化させる場合は凝固時の冷却速度を速くするとよい。鋼板を溶融めっき浴に浸漬してから引き上げる際に、鋼板表面において溶融金属の冷却速度を部分的に速くするか、または遅くすることにより、直線部、曲線部、図形、数字、記号、模様及び文字のいずれか1種またはこれらのうちの2種以上を組合せた形状を、後述する製造方法によって意図的若しくは人工的に現せるようになる。 It is presumed that the first region is formed when the [Al phase] is generated at a relatively low number density in the early stage of solidification of the hot-dip plating layer, and the [Al phase] itself becomes coarse. In addition, the second region is formed when the [Al phase] is generated at a relatively high number density in the early stage of solidification of the hot-dip plating layer, and the [Al phase] itself remains fine without becoming coarse. It is assumed that In order to control the size of the [Al phase], the cooling rate of the molten metal may be controlled during solidification of the hot-dip plated layer. Specifically, if the [Al phase] is to be coarsened, the cooling rate during solidification may be slowed down, and if the [Al phase] is to be made fine, the cooling rate during solidification may be increased. When a steel plate is immersed in a hot-dip plating bath and then pulled up, the cooling rate of the molten metal on the surface of the steel plate is partially accelerated or slowed down, so that straight parts, curved parts, figures, numbers, symbols, patterns, and A shape that is a combination of any one type of character or two or more of these types can be intentionally or artificially created by the manufacturing method described below.
〔Al相〕の平均の長さは、次のような方法で測定する。まず、溶融めっき層の表面のうち、第一領域及び第二領域のそれぞれにおいて、任意の3視野の領域を走査型電子顕微鏡の反射電子像で撮影する。各領域のサイズは、500μm×360μmの矩形の領域とする。撮影された写真において、樹枝状のAl相を確認する。樹枝状のAl相は、概ね、図1に示すように、主軸部と、主軸部から伸びた二次アーム部とを有する形状となっている。写真内のAl相について、長手方向の長さAを測定する。3視野において全てのAl相の長さAを求め、その平均値を第一領域または第二領域におけるAl相の平均長さとする。なお、樹枝状のAl相は、凝固核から放射状に成長することが多いが、同一平面に配列するとは限らず、表面から観察する場合はその一部、例えば、二次アーム先端のみが観察される、または、主軸部のみが観察される場合がある。そのようなAl相は、計測の対象から排除することとする。一方で、主軸と二次アームの間に別の相がかぶさり、つながっていないように観察できるものは対象とする。 The average length of the [Al phase] is measured by the following method. First, in each of the first region and the second region of the surface of the hot-dip plating layer, three arbitrary fields of view are photographed using a backscattered electron image using a scanning electron microscope. The size of each region is a rectangular region of 500 μm×360 μm. In the photograph taken, a dendritic Al phase is confirmed. As shown in FIG. 1, the dendritic Al phase generally has a shape having a main shaft portion and a secondary arm portion extending from the main shaft portion. The length A in the longitudinal direction of the Al phase in the photograph is measured. The lengths A of all the Al phases in the three fields of view are determined, and the average value thereof is taken as the average length of the Al phases in the first region or the second region. Note that the dendritic Al phase often grows radially from the solidification core, but it is not always arranged in the same plane, and when observed from the surface, only a part of it, for example, the tip of the secondary arm, is observed. In some cases, only the main shaft portion is observed. Such an Al phase is excluded from the measurement target. On the other hand, objects in which another phase overlaps the main axis and the secondary arm and can be observed as not being connected are targeted.
<化成処理皮膜層及び塗膜層>
本実施形態に係るZn-Al-Mg系溶融めっき鋼板は、溶融めっき層の表面に化成処理皮膜層や塗膜層を有してもよい。ここで、化成処理皮膜層や塗膜層の種類は特に限定されず、公知の化成処理皮膜層や塗膜層を用いることができる。
<Chemical conversion coating layer and coating layer>
The Zn-Al-Mg hot-dip plated steel sheet according to the present embodiment may have a chemical conversion coating layer or a coating layer on the surface of the hot-dip coating layer. Here, the type of the chemical conversion coating layer or coating layer is not particularly limited, and any known chemical conversion coating layer or coating layer can be used.
[Zn-Al-Mg系溶融めっき鋼板の製造方法]
以下、本実施形態のZn-Al-Mg系溶融めっき鋼板の製造方法を説明する。
まず、熱間圧延鋼板を製造し、必要に応じて熱延板焼鈍を行う。酸洗後、冷間圧延を行い、冷延板とする。冷延板を脱脂、水洗した後、焼鈍(冷延板焼鈍)し、焼鈍後の冷延板を溶融めっき浴に浸漬させて溶融めっき層を形成する。溶融めっきは、鋼板を溶融めっき浴に連続通板させる連続式溶融めっき法でもよく、鋼板を所定の形状に加工した鋼材または鋼板自体を、溶融めっき浴に浸漬してから引き上げるどぶ付け式めっき法でもよい。
[Method for manufacturing Zn-Al-Mg hot-dipped steel sheet]
The method for manufacturing the Zn-Al-Mg hot-dip plated steel sheet of this embodiment will be described below.
First, a hot-rolled steel plate is manufactured, and if necessary, the hot-rolled plate is annealed. After pickling, cold rolling is performed to obtain a cold rolled sheet. After the cold-rolled sheet is degreased and washed with water, it is annealed (cold-rolled sheet annealing), and the annealed cold-rolled sheet is immersed in a hot-dip plating bath to form a hot-dip plating layer. Hot-dip plating may be a continuous hot-dip plating method in which the steel sheet is continuously passed through a hot-dip plating bath, or a dip-type plating method in which the steel sheet processed into a predetermined shape or the steel sheet itself is immersed in the hot-dip plating bath and then pulled up. But that's fine.
溶融めっき浴は、Al:4質量%以上25質量%未満、Mg:0質量%以上10質量%未満を含有し、残部としてZnおよび不純物を含むことが好ましい。また、溶融めっき浴は、Al:4~22質量%、Mg:1~10質量%を含有し、残部がZnおよび不純物を含むものでもよい。更に、溶融めっき浴は、Si:0.0001~2質量%を含有してもよい。更にまた、溶融めっき浴は、Ni、Ti、Zr、Sr、Sb、Pb、Sn、Ca、Co、Mn、P、B、Bi、Cr、Sc、Y、REM、Hfのいずれか1種または2種以上を、合計で0.001~2質量%含有してもよい。なお、本実施形態の溶融めっき層の平均組成は、溶融めっき浴の組成とほぼ同じである。 The hot-dip plating bath preferably contains Al: 4% by mass or more and less than 25% by mass, Mg: 0% by mass or more and less than 10% by mass, and the balance contains Zn and impurities. Further, the hot-dip plating bath may contain Al: 4 to 22% by mass, Mg: 1 to 10% by mass, and the balance may contain Zn and impurities. Furthermore, the hot-dip plating bath may contain Si: 0.0001 to 2% by mass. Furthermore, the hot-dip plating bath contains any one or two of Ni, Ti, Zr, Sr, Sb, Pb, Sn, Ca, Co, Mn, P, B, Bi, Cr, Sc, Y, REM, and Hf. The total content of 0.001 to 2% by mass of at least one species may be included. Note that the average composition of the hot-dip plating layer of this embodiment is almost the same as the composition of the hot-dip plating bath.
溶融めっき浴の温度は、組成によって異なるが、例えば、400~500℃の範囲が好ましい。溶融めっき浴の温度がこの範囲であれば、所望の溶融めっき層を形成できるためである。
また、溶融めっき層の付着量は、溶融めっき浴から引き上げられた鋼板に対してガスワイピング等の手段で調整すればよい。溶融めっき層の付着量は、鋼板両面の合計の付着量が30~600g/m2の範囲になるように調整することが好ましい。付着量が30g/m2未満の場合、溶融めっき鋼板の耐食性が低下するので好ましくない。付着量が600g/m2超の場合、鋼板に付着した溶融金属の垂れが発生して、溶融めっき層の表面を平滑にすることができなくなるため好ましくない。
The temperature of the hot-dip plating bath varies depending on the composition, but is preferably in the range of 400 to 500°C, for example. This is because if the temperature of the hot-dip plating bath is within this range, a desired hot-dip plating layer can be formed.
Further, the amount of the hot-dip coating layer to be deposited may be adjusted by means such as gas wiping on the steel sheet pulled out of the hot-dip coating bath. The amount of hot-dip plating layer deposited is preferably adjusted so that the total amount of deposit on both sides of the steel plate is in the range of 30 to 600 g/m 2 . If the adhesion amount is less than 30 g/m 2 , the corrosion resistance of the hot-dip plated steel sheet decreases, which is not preferable. If the amount of adhesion exceeds 600 g/m 2 , the molten metal adhering to the steel plate will sag, making it impossible to make the surface of the hot-dip plating layer smooth, which is not preferable.
第一領域及び第二領域を形成するためには、溶融めっき層の付着量を調整した後、鋼板全体を冷却しつつ、溶融状態の金属に対して非酸化性ガスをガスノズルによって局所的に吹き付ける。非酸化性ガスとしては窒素やアルゴンなどの非酸化性ガスを用いるとよい。 In order to form the first region and the second region, after adjusting the adhesion amount of the hot-dip plating layer, while cooling the entire steel plate, non-oxidizing gas is locally sprayed onto the molten metal using a gas nozzle. . As the non-oxidizing gas, it is preferable to use a non-oxidizing gas such as nitrogen or argon.
第一領域を所定の形状になるようにするためには、第二領域の形成のために溶融めっき層のほぼ全体に対して浴温から345℃までの間の平均冷却速度を10℃/秒以上で冷却する。また、第一領域の形成のために溶融めっき層の一部に対して浴温から345℃までの間の平均冷却速度を、第二領域よりも遅い速度である8℃/秒未満で冷却する。 In order to form the first region into a predetermined shape, an average cooling rate of 10°C/sec from the bath temperature to 345°C is applied to almost the entire hot-dip plating layer to form the second region. Cool at this temperature. In addition, in order to form the first region, the average cooling rate for a part of the hot-dip plating layer from the bath temperature to 345°C is lower than 8°C/sec, which is slower than that for the second region. .
より好ましくは、第二領域の形成のために溶融めっき層のほぼ全体に対して送風冷却またはミスト冷却を行って浴温から345℃までの間の平均冷却速度を15℃/秒以上にしつつ、第一領域の形成のために溶融めっき層の一部に対して冷却せずに放冷(放置)するか、もしくは比較的高温の非酸化性ガスを吹き付けることで、浴温から345℃までの間の平均冷却速度を5℃/秒以下とする。この場合の非酸化性ガスの温度は、例えば、100~300℃の範囲とするとよい。ただし、上記の平均冷却速度を満足できるならば、非酸化性ガスの温度は限定する必要はない。 More preferably, in order to form the second region, air cooling or mist cooling is performed on almost the entire hot-dip plating layer so that the average cooling rate from the bath temperature to 345° C. is 15° C./sec or more, To form the first region, a part of the hot-dip plating layer is allowed to cool without being cooled, or by blowing a relatively high temperature non-oxidizing gas, the temperature is increased from the bath temperature to 345°C. The average cooling rate during this period is 5°C/second or less. The temperature of the non-oxidizing gas in this case is preferably in the range of 100 to 300°C, for example. However, the temperature of the non-oxidizing gas does not need to be limited as long as the above average cooling rate can be satisfied.
また、第二領域を所定の形状になるようにするためには、第一領域の形成のために溶融めっき層のほぼ全体に対して浴温から345℃までの間の平均冷却速度を8℃/秒以下で冷却する。また、第二領域の形成のために溶融めっき層の一部に対して浴温から345℃までの間の平均冷却速度を、第一領域よりも速い速度である10℃/秒以上で冷却する。 In addition, in order to form the second region into a predetermined shape, the average cooling rate from the bath temperature to 345°C must be set at 8°C for almost the entire hot-dip plating layer to form the first region. Cools down in less than /second. In addition, in order to form the second region, the average cooling rate from the bath temperature to 345°C for a part of the hot-dip plating layer is 10°C/sec or more, which is faster than that in the first region. .
より好ましくは、第一領域の形成のために溶融めっき層のほぼ全体を放冷して浴温から345℃までの間の平均冷却速度を5℃/秒以下にしつつ、第二領域の形成のために溶融めっき層の一部に対して比較的低温の非酸化性ガスを吹き付けることで、浴温から345℃までの間の平均冷却速度を15℃/秒以上とする。第一領域の冷却は、冷却速度を低下させるために、50~150℃の雰囲気中で行ってもよい。また、第二領域を冷却する際の非酸化性ガスの温度は、例えば、10~30℃の範囲としてもよく、水滴を含むミストガスとしてもよい。ただし、上記の平均冷却速度を満足できるならば、第一領域の冷却時の雰囲気温度や非酸化性ガスの温度は、限定する必要はない。 More preferably, almost the entire hot-dip plating layer is left to cool to form the first region, and the average cooling rate from the bath temperature to 345° C. is 5° C./sec or less, while the second region is formed. Therefore, by spraying a relatively low temperature non-oxidizing gas onto a part of the hot-dip plating layer, the average cooling rate from the bath temperature to 345°C is set to 15°C/second or more. Cooling of the first region may be performed in an atmosphere of 50 to 150° C. to reduce the cooling rate. Further, the temperature of the non-oxidizing gas when cooling the second region may be, for example, in the range of 10 to 30° C., or may be a mist gas containing water droplets. However, as long as the above average cooling rate can be satisfied, there is no need to limit the ambient temperature or the temperature of the non-oxidizing gas during cooling of the first region.
更に、溶融めっき層の表面に化成処理層を形成する場合には、溶融めっき層を形成した後の溶融めっき鋼板に対して、化成処理を行う。化成処理の種類は特に限定されず、公知の化成処理を用いることができる。
また、溶融めっき層の表面や化成処理層の表面に塗膜層を形成する場合には、溶融めっき層を形成した後、又は、化成処理層を形成した後の溶融めっき鋼板に対して、塗装処理を行う。塗装処理の種類は特に限定されず、公知の塗装処理を用いることができる。
Furthermore, when forming a chemical conversion treatment layer on the surface of the hot-dip plating layer, the chemical conversion treatment is performed on the hot-dip plated steel sheet after the hot-dip plating layer has been formed. The type of chemical conversion treatment is not particularly limited, and any known chemical conversion treatment can be used.
In addition, when forming a coating layer on the surface of the hot-dip plating layer or the surface of the chemical conversion treatment layer, coating the hot-dip plated steel sheet after forming the hot-dip plating layer or after forming the chemical conversion treatment layer Perform processing. The type of coating treatment is not particularly limited, and any known coating treatment can be used.
本実施形態のZn-Al-Mg系溶融めっき鋼板は、第一領域を溶融めっき層の表面におけるAl相の平均長さが200μm以上の領域とし、第二領域を、溶融めっき層の表面におけるAl相の平均長さが200μm未満の領域とすることで、第一領域と第二領域を識別できるようになる。第一領域及び第二領域は、印刷や塗装によって形成されたものではないため、耐久性が高くなっている。また、第一領域及び第二領域が印刷や塗装によって形成されたものではないため、溶融めっき層の耐食性への影響もない。更に、第一領域及び第二領域は、溶融めっき層の表面を研削等によって形成したものではない。従って、各領域における溶融めっき層の厚みは、耐食性が劣化するほどのめっき層の厚みの減少がみられず、耐食性を低下させない。また、第一領域または第二領域を、所定の形状、例えば、直線部、曲線部、図形、数字、記号、模様若しくは文字のいずれか1種またはこれらのうちの2種以上を組合せた形状となるように意図的若しくは人工的に配置することで、溶融めっき層に意匠、商標、その他の識別マークなどを表すことができ、また、工程管理や在庫管理に必要な情報なども現すことができる。これらは、耐久性が高く、また、溶融めっき鋼板の優れた耐食性を阻害することがない。 In the Zn-Al-Mg hot-dip plated steel sheet of the present embodiment, the first region is a region in which the average length of the Al phase on the surface of the hot-dip coating layer is 200 μm or more, and the second region is a region in which the average length of the Al phase on the surface of the hot-dip coating layer is 200 μm or more. The first region and the second region can be distinguished by setting the region to a region where the average phase length is less than 200 μm. Since the first region and the second region are not formed by printing or painting, they have high durability. Further, since the first region and the second region are not formed by printing or painting, there is no influence on the corrosion resistance of the hot-dip plating layer. Furthermore, the first region and the second region are not formed by grinding the surface of the hot-dip plating layer. Therefore, the thickness of the hot-dip plating layer in each region does not decrease to the extent that the corrosion resistance deteriorates, and the corrosion resistance does not deteriorate. Further, the first region or the second region may be formed into a predetermined shape, for example, a straight portion, a curved portion, a figure, a number, a symbol, a pattern, or a character, or a combination of two or more of these. By intentionally or artificially arranging the hot-dip plating layer, designs, trademarks, and other identification marks can be displayed on the hot-dip plating layer, and information necessary for process control and inventory management can also be displayed. . These have high durability and do not impede the excellent corrosion resistance of hot-dip galvanized steel sheets.
本実施形態によれば、所定の形状に成形した第一領域または第2領域の耐久性が高く、耐食性等の好適なめっき特性を有する溶融めっき鋼板を提供できる。また、本実施形態では、めっき浴から引き上げ後の溶融状態の溶融めっき層の冷却速度を制御しつつ、溶融状態の溶融めっき層の表面に非酸化性ガスをガスノズルによって局所的に吹き付けることで、凝固後の溶融めっき層の〔Al相〕の平均の長さを意図的に調整することができ、直線部、曲線部、ドット部、図形、数字、記号、模様若しくは文字のいずれか1種またはこれらのうちの2種以上を組合せた形状となるように第一領域または第二領域を配置できる。これにより、溶融めっき層の表面に、印刷、塗装または研削を行うことなく様々な意匠、商標、その他の識別マークを表すことができ、鋼板の出所の識別性やデザイン性等を高めることができる。また、第一領域または第二領域を所定の形状に成形することで、工程管理や在庫管理などに必要な情報や需要者が求める任意の情報を、溶融めっき層の表面に付与することもでき、溶融めっき鋼板の生産性の向上にも寄与することができる。 According to this embodiment, it is possible to provide a hot-dip plated steel sheet in which the first region or the second region formed into a predetermined shape has high durability and has suitable plating characteristics such as corrosion resistance. In addition, in this embodiment, while controlling the cooling rate of the molten hot-dip plating layer after being pulled out of the plating bath, a non-oxidizing gas is locally sprayed onto the surface of the molten hot-dip plating layer using a gas nozzle. The average length of the [Al phase] of the hot-dip plating layer after solidification can be intentionally adjusted, and any one of straight parts, curved parts, dotted parts, figures, numbers, symbols, patterns, or characters, or The first region or the second region can be arranged to have a shape that is a combination of two or more of these. As a result, various designs, trademarks, and other identification marks can be displayed on the surface of the hot-dip coating layer without printing, painting, or grinding, and it is possible to improve the identifiability of the origin of the steel plate and the design quality. . In addition, by forming the first region or the second region into a predetermined shape, information necessary for process control, inventory management, etc., or any information desired by consumers can be added to the surface of the hot-dip plating layer. , it can also contribute to improving the productivity of hot-dip galvanized steel sheets.
次に、本発明の実施例を説明する。鋼板を脱脂、水洗した後に、還元焼鈍、めっき浴浸漬、付着量制御、冷却を行うことで、表2A及び表2Bに示すNo.1~21の溶融めっき鋼板を製造した。付着量制御後の冷却は、めっき浴から鋼板を引き上げてからガスワイピングによって付着量を調整したのちに、鋼板全体を冷却しつつ、溶融状態の金属に対して窒素ガスをガスノズルによって局所的に吹き付けた。その後、冷却して溶融金属を完全に凝固させた。窒素ガスの吹き付け範囲は、50mm間隔の格子状パターンとなるように制御した。表1に冷却条件を示す。表1に示す平均冷却速度は、いずれも、浴温から345℃までの間の平均冷却速度である。 Next, examples of the present invention will be described. After degreasing and washing the steel plate with water, reduction annealing, immersion in a plating bath, coating amount control, and cooling were performed to obtain No. 1 shown in Tables 2A and 2B. Hot-dip galvanized steel sheets Nos. 1 to 21 were manufactured. Cooling after controlling the amount of adhesion involves lifting the steel sheet from the plating bath, adjusting the amount of adhesion using gas wiping, and then locally spraying nitrogen gas onto the molten metal using a gas nozzle while cooling the entire steel sheet. Ta. Thereafter, the molten metal was completely solidified by cooling. The spraying range of nitrogen gas was controlled to form a grid pattern with intervals of 50 mm. Table 1 shows the cooling conditions. The average cooling rates shown in Table 1 are all average cooling rates from the bath temperature to 345°C.
冷却条件A~Cによって第二領域で格子状パターンを表現させ、冷却条件Dによって第一領域で格子状パターンを表現させた。また、冷却条件E、Fは、比較例のパターンとした。 A lattice pattern was expressed in the second region under cooling conditions A to C, and a lattice pattern was expressed in the first region under cooling condition D. In addition, cooling conditions E and F were used as a pattern of a comparative example.
冷却条件Aは、鋼板全体を120℃の雰囲気中で徐冷しつつ、非酸化性ガスとして30℃の窒素ガスを吹き付けた。
冷却条件Bは、鋼板全体を放冷しつつ、非酸化性ガスとして20℃の窒素ガスを吹き付けた。
冷却条件Cは、鋼板全体を放冷しつつ、非酸化性ガスとしてミストを含む窒素ガスを吹き付けた。
冷却条件Dは、鋼板全体を、ミストを含む窒素ガスで冷却しつつ、非酸化性ガスとして250℃の窒素ガスを吹き付けた。
また、冷却条件Eは、鋼板全体を30℃の窒素ガス中で放冷しつつ、非酸化性ガスとして30℃の窒素ガスを吹き付けた。冷却条件Fは、鋼板全体を放冷した。
Cooling condition A was such that the entire steel plate was slowly cooled in an atmosphere at 120°C, and nitrogen gas at 30°C was sprayed as a non-oxidizing gas.
In cooling condition B, nitrogen gas at 20° C. was blown as a non-oxidizing gas while the entire steel plate was allowed to cool.
In cooling condition C, nitrogen gas containing mist was sprayed as a non-oxidizing gas while the entire steel plate was allowed to cool.
Cooling condition D was such that the entire steel plate was cooled with nitrogen gas containing mist, and nitrogen gas at 250° C. was sprayed as a non-oxidizing gas.
Further, under cooling condition E, the entire steel plate was allowed to cool in nitrogen gas at 30°C, and nitrogen gas at 30°C was sprayed as a non-oxidizing gas. Cooling condition F was cooling the entire steel plate.
また、上記と同様にしてZn-Al-Mg系溶融めっき鋼板を製造した。その後、溶融めっき層の表面に、インクジェット法により、50mm間隔の格子状パターンを印刷した。この結果をNo.22として表2A及び表2Bに示す。 In addition, a Zn-Al-Mg hot-dip plated steel sheet was manufactured in the same manner as above. Thereafter, a grid pattern with an interval of 50 mm was printed on the surface of the hot-dip plating layer by an inkjet method. This result is No. 22 in Tables 2A and 2B.
更に、上記と同様にしてZn-Al-Mg系溶融めっき鋼板を製造した。その後、溶融めっき層の表面を研削して、50mm間隔の格子状パターンを形成した。この結果をNo.23として表2A及び表2Bに示す。 Furthermore, a Zn--Al--Mg hot-dip galvanized steel sheet was produced in the same manner as above. Thereafter, the surface of the hot-dip plating layer was ground to form a lattice pattern with intervals of 50 mm. This result is No. 23 in Tables 2A and 2B.
得られた溶融めっき鋼板について、第一領域及び第二領域におけるAl相の平均長さを求めた。まず、第一領域及び第二領域の境界は、溶融めっき層の表面を肉眼で観察することにより特定した。境界の判別が難しい例では、窒素ガスの吹き付け範囲が第一領域または第二領域であるとした。 Regarding the obtained hot-dip plated steel sheet, the average length of the Al phase in the first region and the second region was determined. First, the boundary between the first region and the second region was identified by visually observing the surface of the hot-dip plating layer. In an example where it is difficult to determine the boundary, the range of nitrogen gas spraying is determined to be the first region or the second region.
〔Al相〕の平均の長さは、次のような方法で測定した。まず、溶融めっき層の表面のうち、第一領域及び第二領域のそれぞれにおいて、任意の3視野の領域を走査型電子顕微鏡の反射電子像で撮影した。各領域のサイズは、500μm×360μmの矩形の領域とした。撮影された写真において、樹枝状のAl相を確認した。樹枝状のAl相は、概ね、図1に示すように、主軸部と、主軸部から伸びた一次アーム部とを有する形状となっていた。写真内のAl相について、長手方向の長さAを測定した。3視野において全てのAl相の長さAを求め、その平均値を第一領域または第二領域におけるAl相の平均長さとした。なお、樹枝状のAl相は、凝固核から放射状に成長することが多いが、同一平面に配列するとは限らず、表面から観察する場合はその一部、例えば、アーム先端のみが観察される、または、主軸部のみが観察される場合がある。そのようなAl相は、計測の対象から排除した。一方で、主軸とアームの間に別の相がかぶさり、つながっていないように観察できるものは測定対象とした。 The average length of the [Al phase] was measured by the following method. First, in each of the first region and the second region of the surface of the hot-dip plating layer, three arbitrary fields of view were photographed using a backscattered electron image using a scanning electron microscope. The size of each region was a rectangular region of 500 μm×360 μm. In the photograph taken, a dendritic Al phase was confirmed. The dendritic Al phase generally had a shape having a main axis and a primary arm extending from the main axis, as shown in FIG. The length A in the longitudinal direction was measured for the Al phase in the photograph. The lengths A of all the Al phases in the three visual fields were determined, and the average value thereof was taken as the average length of the Al phases in the first region or the second region. Note that the dendritic Al phase often grows radially from the solidification core, but it is not always arranged in the same plane, and when observed from the surface, only a part of it, for example, the tip of the arm, is observed. Alternatively, only the main shaft portion may be observed. Such an Al phase was excluded from measurement. On the other hand, objects in which another phase overlaps the main axis and the arm and can be observed as not being connected were targeted for measurement.
[識別性]
格子状のパターンを施した試験板の、製造した直後の初期状態のものと、6ヶ月間屋外暴露した経時状態のものを対象に、下記の判定基準に基づいて目視評価した。初期状態、経時状態とも、◎~△を合格とした。
[Identifiability]
Visual evaluation was performed based on the following criteria for test plates with a grid pattern, both in the initial state immediately after manufacture and in the aged state after being exposed outdoors for 6 months. In both the initial state and the aged state, ◎ to △ were considered to be passed.
◎:5m先からでも格子状パターンを視認できる。
○:5m先からは格子状パターンを視認できないが、3m先からの視認性は高い。
△:3m先からは格子状パターンを視認できないが、1m先からの視認性は高い。
×:1m先から格子状パターンを視認できない。
◎: The grid pattern is visible even from 5 meters away.
○: The grid pattern cannot be seen from 5 m away, but visibility is high from 3 m away.
Δ: The grid pattern cannot be seen from 3 m away, but visibility is high from 1 m away.
×: The grid pattern cannot be seen from 1 meter away.
[耐食性]
試験板を150×70mmに切断し、JASO-M609に準拠した腐食促進試験CCTを30サイクル試験した後、錆発生状況を調査し、下記の判定基準に基づいて評価した。◎~△を合格とした。
◎:錆発生がなく、格子状パターンとそれ以外の領域がともに美麗な意匠外観を維持している。
○:錆発生はないが、格子状パターンとそれ以外の領域にごくわずかな意匠外観変化が認められる。
△:意匠外観がやや損なわれているが、格子状パターンとそれ以外の領域が目視で区別できる。
×:格子状パターンとそれ以外の領域の外観品位が著しく低下しており、目視で区別できない。
[Corrosion resistance]
The test plate was cut into 150 x 70 mm and subjected to 30 cycles of accelerated corrosion test CCT in accordance with JASO-M609, and then the rust occurrence was investigated and evaluated based on the following criteria. ◎~△ was considered a pass.
◎: No rust occurs, and both the grid pattern and other areas maintain a beautiful design appearance.
○: No rust occurred, but a very slight change in design appearance was observed in the grid pattern and other areas.
Δ: The design appearance is slightly impaired, but the grid pattern and other areas can be visually distinguished.
×: The appearance quality of the lattice pattern and other areas is significantly degraded and cannot be visually distinguished.
表2A及び表2Bに示すように、No.1~No.19の本発明例のZn-Al-Mg系溶融めっき鋼板は、識別性及び耐食性の両方に優れていた。図2に、No.4の第一領域の走査型電子顕微鏡による観察結果を示し、図3に、No.4の第二領域における走査型電子顕微鏡による観察結果を示す。図2に示す第一領域における〔Al相〕は、図3に示す第二領域における〔Al相〕に比べて、〔Al相〕の平均長さが大きくなっており、それぞれ異なった外観を呈しており、第一領域及び第二領域が識別可能であることがわかる。 As shown in Tables 2A and 2B, No. 1~No. The Zn-Al-Mg hot-dipped steel sheet of No. 19 inventive example was excellent in both identifiability and corrosion resistance. In FIG. 2, No. FIG. 3 shows the observation results of the first region of No. 4 using a scanning electron microscope. The results of observation using a scanning electron microscope in the second region of No. 4 are shown. The [Al phase] in the first region shown in FIG. 2 has a larger average length than the [Al phase] in the second region shown in FIG. 3, and each has a different appearance. It can be seen that the first region and the second region are distinguishable.
No.20及びNo.21は、冷却条件が適切でなかったため、格子状パターンが確認されなかった。 No. 20 and no. In No. 21, no lattice pattern was observed because the cooling conditions were not appropriate.
また、インクジェット法で格子状のパターンを印刷したNo.22は、6ヶ月間の屋外暴露によってパターンが薄くなり、識別性が低下した。
また、研削によって格子状のパターンを形成したNo.23は、研削した箇所のめっき層の厚みが低下し、研削箇所での耐食性が低下した。
In addition, No. 1 printed a grid pattern using an inkjet method. In No. 22, the pattern became thinner and the distinguishability decreased after being exposed to the outdoors for 6 months.
In addition, No. 1, in which a grid pattern was formed by grinding. In No. 23, the thickness of the plating layer at the ground location decreased, and the corrosion resistance at the ground location decreased.
なお、No.1~No.23のめっき層には、Al相と、Al/Zn/MgZn2の三元共晶組織とを含んでいた。 In addition, No. 1~No. The plating layer of No. 23 contained an Al phase and a ternary eutectic structure of Al/Zn/MgZn 2 .
図4には、Zn-Al-Mg系溶融めっき層に窒素ガスの吹き付けることにより、文字列(アルファベット)を表した溶融めっき鋼板の表面を示す。
本発明によれば、溶融めっき鋼板の表面に、文字やマークを意図的に表すことができるようになる。
FIG. 4 shows the surface of a hot-dip plated steel plate on which a character string (alphabet) is expressed by blowing nitrogen gas onto the Zn-Al-Mg hot-dip plated layer.
According to the present invention, letters and marks can be intentionally displayed on the surface of a hot-dip plated steel plate.
Claims (5)
前記鋼板の表面に形成された溶融めっき層と、
を備え、
前記溶融めっき層は、
平均組成で、Al:4質量%以上25質量%未満、Mg:0質量%以上10質量%未満を含有し、残部がZnおよび不純物を含み、
金属組織として、樹枝晶状のAl相と、Al/Zn/MgZn2の三元共晶組織とを含み、
前記溶融めっき層は、第一領域と第二領域とを含み、
前記第一領域および前記第二領域にはそれぞれ、複数の前記樹枝晶状のAl相が含まれ、
前記第一領域は、前記溶融めっき層の表面における前記Al相の平均長さが200μm以上の領域であり、
前記第二領域は、前記溶融めっき層の表面における前記Al相の平均長さが200μm未満の領域であり、
前記第一領域または前記第二領域が、直線部、曲線部、図形、数字、記号、模様若しくは文字のいずれか1種またはこれらのうちの2種以上を組合せた意図的な形状である、ことを特徴とするZn-Al-Mg系溶融めっき鋼板。 steel plate and
a hot-dip plating layer formed on the surface of the steel plate;
Equipped with
The hot-dip plating layer is
The average composition contains Al: 4% by mass or more and less than 25% by mass, Mg: 0% by mass or more and less than 10% by mass, and the balance contains Zn and impurities,
The metal structure includes a dendritic Al phase and a ternary eutectic structure of Al/Zn/ MgZn2 ,
The hot-dip plating layer includes a first region and a second region,
The first region and the second region each include a plurality of the dendrite-like Al phases,
The first region is a region in which the average length of the Al phase on the surface of the hot-dip plating layer is 200 μm or more,
The second region is a region where the average length of the Al phase on the surface of the hot-dip plating layer is less than 200 μm,
The first region or the second region has an intentional shape consisting of any one of a straight part, a curved part, a figure, a number, a symbol, a pattern, or a character, or a combination of two or more of these. A Zn-Al-Mg hot-dip plated steel sheet.
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CN202080080847.9A CN114729437A (en) | 2019-11-29 | 2020-07-02 | Zn-Al-Mg hot-dip coated steel sheet |
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001262305A (en) | 2000-03-15 | 2001-09-26 | Sumitomo Metal Ind Ltd | HOT DIP Zn-Al BASE ALLOY COATED STEEL SHEET EXCELLENT IN WORKABILITY AND ITS PRODUCING METHOD |
JP2003268517A (en) | 2002-03-08 | 2003-09-25 | Nippon Steel Corp | Hot dip plated steel having excellent surface smoothness |
WO2004038060A1 (en) | 2002-10-28 | 2004-05-06 | Nippon Steel Corporation | High corrosion-resistant hot dip coated steel product excellent in surface smoothness and formability, and method for producing hot dip coated steel product |
WO2011001662A1 (en) | 2009-06-30 | 2011-01-06 | 新日本製鐵株式会社 | Zn-Al-Mg HOT-DIP COATED STEEL SHEET AND PROCESS FOR PRODUCTION THEREOF |
WO2013002358A1 (en) | 2011-06-30 | 2013-01-03 | 新日鐵住金株式会社 | High-corrosion-resistance hot-dip galvanized steel plate having highly uniform appearance and manufacturing method therefor |
WO2016162982A1 (en) | 2015-04-08 | 2016-10-13 | 新日鐵住金株式会社 | Zn-Al-Mg-PLATED STEEL SHEET AND METHOD FOR MANUFACTURING Zn-Al-Mg-PLATED STEEL SHEET |
WO2019221193A1 (en) | 2018-05-16 | 2019-11-21 | 日本製鉄株式会社 | Plated steel material |
-
2019
- 2019-11-29 JP JP2019216685A patent/JP7381864B2/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001262305A (en) | 2000-03-15 | 2001-09-26 | Sumitomo Metal Ind Ltd | HOT DIP Zn-Al BASE ALLOY COATED STEEL SHEET EXCELLENT IN WORKABILITY AND ITS PRODUCING METHOD |
JP2003268517A (en) | 2002-03-08 | 2003-09-25 | Nippon Steel Corp | Hot dip plated steel having excellent surface smoothness |
WO2004038060A1 (en) | 2002-10-28 | 2004-05-06 | Nippon Steel Corporation | High corrosion-resistant hot dip coated steel product excellent in surface smoothness and formability, and method for producing hot dip coated steel product |
WO2011001662A1 (en) | 2009-06-30 | 2011-01-06 | 新日本製鐵株式会社 | Zn-Al-Mg HOT-DIP COATED STEEL SHEET AND PROCESS FOR PRODUCTION THEREOF |
WO2013002358A1 (en) | 2011-06-30 | 2013-01-03 | 新日鐵住金株式会社 | High-corrosion-resistance hot-dip galvanized steel plate having highly uniform appearance and manufacturing method therefor |
WO2016162982A1 (en) | 2015-04-08 | 2016-10-13 | 新日鐵住金株式会社 | Zn-Al-Mg-PLATED STEEL SHEET AND METHOD FOR MANUFACTURING Zn-Al-Mg-PLATED STEEL SHEET |
WO2019221193A1 (en) | 2018-05-16 | 2019-11-21 | 日本製鉄株式会社 | Plated steel material |
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