JP2011153368A - High-strength hot dip galvannealed steel sheet having excellent adhesion, and method for producing the same - Google Patents
High-strength hot dip galvannealed steel sheet having excellent adhesion, and method for producing the same Download PDFInfo
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本発明は、合金化溶融亜鉛めっき鋼板およびその製造方法に関し、具体的には、フレーキング性および表面性状に優れる高強度合金化溶融亜鉛めっき鋼板、特に、自動車の車体のようにプレス成形、その中でも、複雑な成形が必要となる用途に好適な、密着性に優れた高強度合金化溶融亜鉛めっき鋼板およびその製造方法に関する。 The present invention relates to an alloyed hot-dip galvanized steel sheet and a method for producing the same, specifically, a high-strength alloyed hot-dip galvanized steel sheet having excellent flaking properties and surface properties, particularly press forming like an automobile body, In particular, the present invention relates to a high-strength galvannealed steel sheet excellent in adhesion and suitable for applications requiring complicated forming and a method for producing the same.
近年、自動車の燃費向上が地球環境保護のために求められている。高強度鋼板、特に、防錆性を考慮した部材では高強度溶融亜鉛めっき鋼板へのニーズが、車体の軽量化および乗員の安全性確保のために高まっている。しかし、自動車用部材に供される鋼板は、高強度であるだけでは不十分であり、プレス成形性や耐食性等といった各種性能を満足するものでなければならない。 In recent years, improvement in fuel efficiency of automobiles has been demanded for protecting the global environment. The demand for high-strength hot-dip galvanized steel sheets is increasing in order to reduce the weight of the vehicle body and ensure the safety of passengers. However, a steel sheet used for a member for automobiles is not sufficient if it has only high strength, and must satisfy various performances such as press formability and corrosion resistance.
しかし、高強度化のためにＳｉ、ＭｎやＡｌを多量に含有する高強度鋼板は、溶融亜鉛めっきにおける焼鈍過程において、表面にＭｎやＳｉの酸化皮膜が形成し、亜鉛の濡れ性が低下して、不めっきが生じやすい。また、この高強度鋼板は、溶融亜鉛めっき時に不めっきを生じなくとも、前述の酸化皮膜が加熱合金化時の母材からの鉄の拡散を阻害するために合金化が著しく困難になる。 However, high-strength steel sheets containing a large amount of Si, Mn, and Al to increase the strength of the hot-dip galvanizing annealing process form an oxide film of Mn and Si on the surface, reducing zinc wettability. Therefore, non-plating is likely to occur. Moreover, even if this high-strength steel plate does not undergo non-plating during hot dip galvanization, the above-mentioned oxide film inhibits the diffusion of iron from the base material during the heating alloying, making alloying extremely difficult.
さらに、酸化皮膜が鋼板上に均一に形成されない場合には、部分的に合金化反応が遅く進行する部分と合金化反応が早く進行する部分とが形成され、合金化処理ムラを生じることになる。このような合金化処理ムラが生じると、高強度鋼板のようなプレス成型した際の金型との面圧が非常に高い場合、めっき皮膜が物理的に剥離するフレーキングが度々問題になる。このフレーキングにより、めっき皮膜そのものが金型へ凝着するので、プレス成型の生産性を著しく低下させ問題となる。したがって、このような高強度鋼板においてはフレーキング性を改善することも重要な課題の一つとなる。 Furthermore, when the oxide film is not uniformly formed on the steel plate, a part where the alloying reaction proceeds slowly and a part where the alloying reaction proceeds earlier are formed, resulting in unevenness of the alloying treatment. . When such alloying treatment unevenness occurs, flaking that physically separates the plating film often becomes a problem when the surface pressure with a mold during press molding such as a high-strength steel plate is very high. Due to this flaking, the plating film itself adheres to the mold, which causes a problem that the productivity of press molding is significantly reduced. Therefore, in such a high-strength steel sheet, improving the flaking property is also an important issue.
Ｓｉ、ＭｎやＡｌを多量に含有する高強度鋼板に、フレーキング性が優れるとともに均一な合金化溶融亜鉛皮膜（以下、「ＧＡ皮膜」という。）を形成することは、非常に困難であった。 It was extremely difficult to form a uniform alloyed molten zinc coating (hereinafter referred to as “GA coating”) with excellent flaking properties on a high-strength steel plate containing a large amount of Si, Mn and Al. .
Ｓｉ、ＭｎやＡｌ等の易酸化元素を多量に含有する高強度鋼板において、ＧＡ皮膜を形成する方法として、例えば、特許文献１には、高Ｓｉ、Ｍｎ鋼において、予め、Ｆｅ系のプレめっきを行った後に合金化溶融亜鉛めっきを行うことによる高強度合金化溶融めっき鋼板の製造方法の発明が開示されている。また、特許文献２には、焼鈍により易酸化性元素を表面に濃化させた後に酸洗し、酸化物を除去した後に溶融亜鉛めっきを行う発明が開示されている。さらには、特許文献３には、焼鈍前の鋼板表面に硫黄化合物を塗布した後に合金化溶融亜鉛めっきを行うことによって合金化ムラの発生を抑制する発明も開示されている。 As a method for forming a GA film in a high-strength steel sheet containing a large amount of easily oxidizable elements such as Si, Mn and Al, for example, Patent Document 1 discloses, in advance, Fe-based pre-plating in high Si and Mn steel. An invention of a method for producing a high-strength galvannealed steel sheet by carrying out galvannealing after carrying out is disclosed. Patent Document 2 discloses an invention in which an easily oxidizable element is concentrated on the surface by annealing, followed by pickling and galvanizing after removing the oxide. Furthermore, Patent Document 3 discloses an invention that suppresses the occurrence of alloying unevenness by performing alloying hot dip galvanization after applying a sulfur compound to the surface of the steel sheet before annealing.
しかしながら、特許文献１〜３により開示された発明は、いずれも、合金化溶融亜鉛めっき前に特別な処理を行うために新たな設備を溶融亜鉛めっきラインの前に設置する必要があり、製造コストの上昇は避けられない。 However, all of the inventions disclosed in Patent Documents 1 to 3 require that new equipment be installed in front of the hot dip galvanizing line in order to perform a special treatment before alloying hot dip galvanizing. The rise of is inevitable.
一方、易酸化元素を多量に含有する高強度鋼板の合金化処理方法として、例えば、特許文献４には、焼鈍時の前酸化炉で積極的に鋼板表面を酸化させた後に、還元焼鈍して溶融亜鉛めっきを行う発明が開示されている。さらに、特許文献５には、熱間圧延時の巻取り温度を高温にして、鋼板表面の近傍に積極的に易酸化元素を内部酸化させることによって、溶融亜鉛めっきの密着性の改善を目指した発明も開示されている。このように、易酸化性元素を熱間圧延時の巻取り温度制御や焼鈍炉内の雰囲気制御等によって対応する方法も、ＧＡ化の促進方法の一つとしてよく取られている。 On the other hand, as a method for alloying a high-strength steel sheet containing a large amount of easily oxidizable elements, for example, in Patent Document 4, after the steel sheet surface is actively oxidized in a pre-oxidation furnace during annealing, reduction annealing is performed. An invention for hot dip galvanizing is disclosed. Furthermore, Patent Document 5 aims to improve the adhesion of hot dip galvanizing by increasing the coiling temperature during hot rolling and actively oxidizing an easily oxidizable element in the vicinity of the steel sheet surface. The invention is also disclosed. As described above, a method of dealing with an easily oxidizable element by controlling the coiling temperature during hot rolling or controlling the atmosphere in the annealing furnace is often taken as one of the methods for promoting GA.
しかし、特許文献４により開示された発明では、前酸化炉で酸化された鋼板表面の酸化物層が還元焼鈍炉内で脱落しハースロールに巻き付いて押し込み疵を生じる等の問題がある。また、近年は前酸化炉を備えない設備も使用されつつあり、特許文献４により開示された発明を適用できないことも少なくない。 However, in the invention disclosed in Patent Document 4, there is a problem that the oxide layer on the surface of the steel plate oxidized in the pre-oxidation furnace falls off in the reduction annealing furnace and winds around the hearth roll to cause indentation flaws. In recent years, equipment not equipped with a pre-oxidation furnace is being used, and the invention disclosed in Patent Document 4 is often not applicable.
一方、特許文献５により開示された発明では、鋼板に求められる機械特性によっては巻取温度を高くできない場合もある他、巻取温度が高いことにより鋼板の表層部に粒界酸化が進行することに起因して、得られる合金化溶融亜鉛めっき鋼板のめっき密着性（例えばパウダリング性）も必ずしも満足できない。 On the other hand, in the invention disclosed in Patent Document 5, depending on the mechanical properties required of the steel sheet, the coiling temperature may not be increased, and the grain boundary oxidation proceeds to the surface layer portion of the steel sheet due to the high coiling temperature. Due to the above, the plating adhesion (for example, powdering property) of the obtained galvannealed steel sheet cannot always be satisfied.
さらに、特許文献４により開示された発明の課題を解決する技術として、例えば、特許文献６には、前加熱〜焼鈍の領域をＡ、Ｂ、Ｃの３ゾーンに分け、それぞれ加熱雰囲気を変更し、Ａ帯では４００℃〜７５０℃の領域で鋼板表面を積極的に酸化させ、Ｂ帯加熱では６００℃〜８５０℃の温度域でＯ２＜０．１体積％、Ｈ２Ｏ≧１体積％の雰囲気で加熱して、さらに、Ｃ帯において露点０℃以下で加熱する発明が開示されている。Ａ帯及びＢ帯は、直下バーナー若しくは無酸化炉（すなわち前述の前酸化炉に相当）にある領域であり、Ｃ帯は鋼板を最高到達温度付近であり、焼鈍炉内のいわゆる加熱保持帯にあたる領域である。 Furthermore, as a technique for solving the problems of the invention disclosed in Patent Document 4, for example, Patent Document 6 discloses that the preheating to annealing region is divided into three zones A, B, and C, and the heating atmosphere is changed respectively. In the A zone, the surface of the steel sheet is actively oxidized in the region of 400 ° C. to 750 ° C., and in the B zone heating, O 2 <0.1 vol%, H 2 O ≧ 1 vol% in the temperature range of 600 ° C. to 850 ° C. The invention is further disclosed in which heating is performed in the atmosphere and further heating is performed at a dew point of 0 ° C. or lower in the C band. A zone and B zone are areas in the direct burner or non-oxidizing furnace (that is, equivalent to the above-mentioned pre-oxidizing furnace), and C band is the vicinity of the maximum temperature of the steel sheet and corresponds to a so-called heating holding zone in the annealing furnace. It is an area.
しかし、特許文献６により開示された発明においても、前酸化炉を有さない設備へは適用し難い。また、鋼板は、最高温度に加熱保持された後に、亜鉛めっき浴への侵入温度（通常４５０℃〜５００℃）まで冷却されてから、めっきされる。鋼板が焼鈍炉内の加熱保持帯以降の領域（温度履歴によって、冷却帯、低温保持帯等と呼ばれることがある。）にある時間は、通常数十秒のオーダーであるので、この領域で、特許文献６により開示された発明のＣ帯における高露点を維持したままでは、不めっきが生じやすく、また、フレーキング性にも劣る。 However, the invention disclosed in Patent Document 6 is also difficult to apply to equipment that does not have a pre-oxidation furnace. In addition, the steel sheet is heated and held at the maximum temperature, and then cooled to the penetration temperature into the galvanizing bath (usually 450 ° C. to 500 ° C.) before being plated. Since the time in which the steel sheet is in the region after the heating holding zone in the annealing furnace (sometimes called a cooling zone, a low temperature holding zone, etc. depending on the temperature history) is usually on the order of several tens of seconds, If the high dew point in the C-band of the invention disclosed by Patent Document 6 is maintained, non-plating is likely to occur and the flaking property is also inferior.
本発明は、フレーキング性および表面性状に優れる高強度溶融亜鉛めっき鋼板、特に、自動車の車体のようにプレス成形、その中でも、複雑な成形が必要となる用途に好適な、密着性に優れた高強度合金化溶融亜鉛めっき鋼板およびその製造方法を提供することである。 The present invention is a high-strength hot-dip galvanized steel sheet excellent in flaking and surface properties, particularly press-molded like an automobile body, and particularly suitable for applications that require complex molding and excellent adhesion. It is to provide a high-strength galvannealed steel sheet and a method for producing the same.
Ｓｉ、Ｍｎを多く含む母材鋼板に溶融めっきを施す際には、Ｓｉ、Ｍｎの酸化物を鋼板表面にではなく表面直下の内部に形成することが好ましい。そのためには、加熱炉の高温域では、この均一性を保つためには高温域の雰囲気、特に露点を適正に保つ必要がある。さらには、それだけではめっき密着性の確保が難しく、次いで冷却帯や低温保持帯における低温域の露点も適正化することが重要である。 When hot-plating a base steel plate containing a large amount of Si and Mn, it is preferable to form an oxide of Si and Mn not on the surface of the steel plate but inside the surface. For that purpose, in order to maintain this uniformity in the high temperature region of the heating furnace, it is necessary to keep the atmosphere in the high temperature region, particularly the dew point, appropriately. Furthermore, it is difficult to ensure plating adhesion by itself, and it is also important to optimize the low temperature dew point in the cooling zone and the low temperature holding zone.
さらに、このようにして形成される合金化溶融亜鉛めっき鋼板は、めっき層−母材鋼板界面の鋼板の表面の結晶の態様に特徴があることが見出された。
本発明は、以下のとおりである。
Furthermore, it has been found that the alloyed hot-dip galvanized steel sheet formed in this way is characterized by the crystal form on the surface of the steel sheet at the interface between the plating layer and the base steel sheet.
The present invention is as follows.
（１）母材鋼板の表面にＦｅ濃度で７〜１５％（本明細書では特に断りがない限り「％」は「質量％」を意味するものとする）の合金化溶融亜鉛めっき層を少なくとも片面に有する合金化溶融亜鉛めっき鋼板であり、めっき層を酸で溶解除去した母材鋼板の表面の結晶粒内に１μｍ以下の微細な孔を有する結晶が、母材鋼板の表層部に面積率で３０％以上存在することを特徴とする合金化溶融亜鉛めっき鋼板。
（２）前記鋼板が、Ｃ：０．０３〜０．２０％、Ｍｎ：０．０３〜３．０％、Ｓｉ：０．１〜２．５％、Ｓ：０．０１％以下、Ｐ：０．１％以下、ｓｏｌ．Ａｌ：１．０％以下、Ｎ：０．０１％以下の化学組成である上記（１）項に記載された合金化溶融亜鉛めっき鋼板。
（３）前記鋼板が、さらに、Ｂｉ：０．０００１〜０．０５％を含有する上記（２）項に記載された合金化溶融亜鉛めっき鋼板。
（４）前記鋼板が、さらに、Ｔｉ：０．２５％以下、Ｎｂ：０．２５％以下、Ｖ：０．２５％以下、およびＢ：０．０１％以下からなる群から選ばれた１種または２種以上を含有する上記（２）項または（３）項に記載された合金化溶融亜鉛めっき鋼板。
（５）前記鋼板が、さらに、Ｃｒ：１％以下、Ｍｏ：１％以下、Ｃｕ：１％以下およびＮｉ：１％以下からなる群から選ばれた１種または２種以上を含有する上記（２）項から（４）項までのいずれか１項に記載された合金化溶融亜鉛めっき鋼板。
（６）前記鋼板が、さらに、Ｃａ：０．０１％以下、Ｍｇ：０．０１％以下、ＲＥＭ：０．０１％以下、およびＺｒ：０．０１％以下からなる群から選ばれた１種または２種以上を含有する上記（２）項から上記（５）項までのいずれか１項に記載された合金化溶融亜鉛めっき鋼板。
（７）前記鋼板が、さらに、Ｓｂ及びＳｎのいずれか一方または双方を、ＳｂとＳｎとＢｉの合計量で０．００１〜０．０５％含有する上記（２）項から上記（６）項までのいずれか１項に記載された合金化溶融亜鉛めっき鋼板。
（８）合金化溶融亜鉛めっき鋼板の製造方法であって、めっき前の母材鋼板が還元焼鈍炉内の昇温時及び加熱温度保持時で鋼板温度が少なくとも６５０〜９５０℃の温度にある領域ではこの焼鈍炉内の露点を−２５℃以上とし、引き続き鋼板を冷却されてからめっき浴浸漬直前までで鋼板温度が５５０℃以下の領域においては露点を−２５℃以下とすることを特徴とする合金化溶融亜鉛めっき鋼板の製造方法。
（９）前記鋼板が、Ｃ：０．０３〜０．２０％、Ｍｎ：０．０３〜３．０％、Ｓｉ：０．１〜２．５％、Ｓ：０．０１％以下、Ｐ：０．１％以下、ｓｏｌ．Ａｌ：１．０％以下、Ｎ：０．０１％以下の化学組成を有する上記（８）項に記載された合金化溶融亜鉛めっき鋼板の製造方法。
(1) An alloyed hot-dip galvanized layer having an Fe concentration of 7 to 15% (in this specification, “%” means “mass%” unless otherwise specified) is provided on the surface of the base steel plate. An alloyed hot-dip galvanized steel sheet on one side, with crystals having fine pores of 1 μm or less in the crystal grains on the surface of the base steel sheet, where the plating layer has been dissolved and removed with an acid, in the surface layer portion of the base steel sheet An alloyed hot-dip galvanized steel sheet characterized by being present at 30% or more.
(2) The steel sheet is C: 0.03-0.20%, Mn: 0.03-3.0%, Si: 0.1-2.5%, S: 0.01% or less, P: 0.1% or less, sol. The alloyed hot-dip galvanized steel sheet described in the above item (1) having a chemical composition of Al: 1.0% or less and N: 0.01% or less.
(3) The galvannealed steel sheet described in (2) above, wherein the steel sheet further contains Bi: 0.0001 to 0.05%.
(4) The steel sheet is further selected from the group consisting of Ti: 0.25% or less, Nb: 0.25% or less, V: 0.25% or less, and B: 0.01% or less. Alternatively, the galvannealed steel sheet described in the above item (2) or (3), which contains two or more kinds.
(5) The steel sheet further contains one or more selected from the group consisting of Cr: 1% or less, Mo: 1% or less, Cu: 1% or less, and Ni: 1% or less ( The alloyed hot-dip galvanized steel sheet described in any one of items 2) to (4).
(6) The steel sheet is further selected from the group consisting of Ca: 0.01% or less, Mg: 0.01% or less, REM: 0.01% or less, and Zr: 0.01% or less. Alternatively, the galvannealed steel sheet described in any one of (2) to (5) above, which contains two or more.
(7) Item (2) to Item (6) above, wherein the steel sheet further contains 0.001 to 0.05% of one or both of Sb and Sn in a total amount of Sb, Sn, and Bi. The alloyed hot-dip galvanized steel sheet described in any one of items 1 to 4.
(8) A method for producing an alloyed hot-dip galvanized steel sheet, wherein the base steel sheet before plating is in a region where the steel sheet temperature is at least 650 to 950 ° C. when the temperature is increased in the reduction annealing furnace and when the heating temperature is maintained. Then, the dew point in the annealing furnace is set to −25 ° C. or higher, and the dew point is set to −25 ° C. or lower in the region where the steel plate temperature is 550 ° C. or lower immediately after the steel plate is cooled and immediately before immersion in the plating bath. A method for producing a galvannealed steel sheet.
(9) The steel plate is C: 0.03-0.20%, Mn: 0.03-3.0%, Si: 0.1-2.5%, S: 0.01% or less, P: 0.1% or less, sol. The manufacturing method of the galvannealed steel sheet described in the above item (8) having a chemical composition of Al: 1.0% or less and N: 0.01% or less.
本発明により、フレーキング性および表面性状に優れる高強度合金化溶融亜鉛めっき鋼板、特に、自動車の車体のようにプレス成形、その中でも、複雑な成形が必要となる用途に好適な、密着性に優れた高強度合金化溶融亜鉛めっき鋼板およびその製造方法を提供することが可能になる。 In accordance with the present invention, high strength alloyed hot dip galvanized steel sheet with excellent flaking and surface properties, particularly press forming as in the body of an automobile, among them, suitable for applications that require complicated forming, and adhesion It becomes possible to provide an excellent high-strength galvannealed steel sheet and a method for producing the same.
次に、本発明において高強度合金化溶融亜鉛めっき鋼板における母材鋼板の成分組成、並びに溶融亜鉛めっき鋼板、および、その製造条件を前記の如くに限定する理由を説明する。 Next, in the present invention, the component composition of the base steel plate in the high-strength galvannealed steel plate, the hot-dip galvanized steel plate, and the reason for limiting the production conditions as described above will be described.
（Ａ）合金化溶融亜鉛めっきのめっき／母材界面の構造
本発明の合金化溶融亜鉛めっき鋼板では、めっき層−母材鋼板界面の鋼板の表面、すなわち、めっき層を酸で溶解除去した母材鋼板の表面の結晶粒内に１μｍ以下の微細な空孔を有する結晶が、母材鋼板の表層部にＴｏｔａｌ面積率で３０％以上を占める。
(A) Structure of the alloyed hot-dip galvanized plating / base metal interface In the alloyed hot-dip galvanized steel sheet of the present invention, the surface of the steel sheet at the interface between the plating layer and the base steel sheet, that is, the base obtained by dissolving and removing the plating layer with an acid. Crystals having fine pores of 1 μm or less in the crystal grains on the surface of the base steel plate occupy 30% or more of the total area ratio in the surface layer portion of the base steel plate.
図１、２に、後述する実施例において、性能良好な合金化溶融亜鉛めっき鋼板（Ｎｏ．２０）、不良な合金化溶融亜鉛めっき鋼板（Ｎｏ．３１）について、それぞれめっき層を酸で溶解除去した後の母材鋼板の表面の観察像の写真を示す。また、参考に、鋼板表面をさらに拡大した観察像の写真を図３、４に示す。 1 and 2, in the examples described later, the plated layers of the galvannealed steel sheet (No. 20) with good performance and the galvannealed steel sheet (No. 31) with poor performance are dissolved and removed with acid, respectively. The photograph of the observation image of the surface of the base material steel plate after performing is shown. For reference, photographs of observation images obtained by further enlarging the steel sheet surface are shown in FIGS.
図１、２に示すように、フレーキング性が良好なものは、フェライト粒内に微細な孔が均一に多数存在しており、不良材はそのような孔は認められなかった。
なお、めっき除去及び観察の手法は以下のとおりである。
As shown in FIGS. 1 and 2, in the case of good flaking properties, a large number of fine holes were uniformly present in the ferrite grains, and such holes were not observed in the defective material.
In addition, the method of plating removal and observation is as follows.
インヒビター（代表例として朝日化学工業株式会社製イビット）を０．１％程度含有する１０％塩酸水溶液中に２分間以上めっき鋼板を浸漬し（必要に応じ超音波による振動を与える等してもよい）、めっき皮膜を完全に溶解した後、母材表面をＦＥ−ＳＥＭにて８ｋＶ以下の低電圧で５０００倍程度の倍率で撮影する。撮影した像から、微細な孔が存在する結晶の面積率を求める。写真１は面積率１００％であり、写真２は面積率０％である。 Immerse the plated steel plate for 2 minutes or more in a 10% aqueous hydrochloric acid solution containing about 0.1% of an inhibitor (Ibibit manufactured by Asahi Chemical Industry Co., Ltd. as a representative example). ) After completely dissolving the plating film, the surface of the base material is photographed with a FE-SEM at a low voltage of 8 kV or less at a magnification of about 5000 times. From the photographed image, the area ratio of the crystal in which fine holes exist is obtained. Photo 1 has an area ratio of 100%, and Photo 2 has an area ratio of 0%.
さらに、同一の鋼板について数か所同様に撮影して面積率を求め、その平均値をこの鋼板の面積率とする。面積率が３０％以上のものは実用に耐え得る性能レベルにある。好ましくは５０％以上であり、さらに好ましくは６０％以上である。 Further, the same steel sheet is photographed in the same manner at several places to determine the area ratio, and the average value is defined as the area ratio of the steel sheet. Those having an area ratio of 30% or more are at a performance level that can withstand practical use. Preferably it is 50% or more, More preferably, it is 60% or more.
（Ｂ）鋼片乃至は母材鋼板の化学組成
［Ｃ：０．０３〜０．２０％］
Ｃは、高張力を得るのに有効であり、Ｃ含有量が０．０３％未満では必要な高張力を得られない。一方、Ｃ含有量は０．２０％を超えると、靱性や溶接性が低下する。したがって、本発明ではＣ含有量を０．０３％以上０．２０％以下とする。
(B) Chemical composition of steel slab or base steel plate [C: 0.03-0.20%]
C is effective for obtaining a high tension, and if the C content is less than 0.03%, the necessary high tension cannot be obtained. On the other hand, if the C content exceeds 0.20%, the toughness and weldability deteriorate. Therefore, in the present invention, the C content is set to 0.03% or more and 0.20% or less.
［Ｍｎ：０．０３〜３．０％、Ｓｉ：０．１〜２．５％］
Ｓｉは、鋼板を高強度化し、かつフェライトを強化し、組織を均一化するのに有効な成分である。またＭｎは変態強化を促進して高強度化を図るのに有効な成分である。
[Mn: 0.03-3.0%, Si: 0.1-2.5%]
Si is an effective component for increasing the strength of a steel sheet, strengthening ferrite, and making the structure uniform. Mn is an effective component for promoting transformation strengthening and increasing strength.
一方、Ｓｉ、Ｍｎは、鉄よりも易酸化元素であるので、焼鈍中にＳｉ、Ｍｎは、焼鈍中に表面に濃化し、酸化物を形成し易い。その後の溶融亜鉛めっき工程において、これらの易酸化元素が表面に酸化物として存在する場合は、溶融めっきがはじくという不めっきが生じやすくなる。さらに、易酸化元素が鋼板表面に存在すると、溶融亜鉛めっきを形成後、直ちに加熱処理するＧＡ化工程において、母材からの鉄拡散の障壁になるために、ＧＡ化が極めて困難になるとともに、ＧＡとの密着性が低下し均一な反応がおこらずにフレーキング性も劣化する。以上の理由から、本発明においては、Ｍｎ含有量を０．０３％以上３．０％以下とし、Ｓｉ含有量を０．１％以上２．５％以下とする。これらの範囲では、Ｓｉ、Ｍｎの表面濃化、酸化物の形成量が多くなり、通常の操業条件では、ＧＡ化処理が困難になり、本発明における効果がより発揮されるためである。 On the other hand, since Si and Mn are more easily oxidizable elements than iron, Si and Mn tend to concentrate on the surface during annealing and form oxides. In the subsequent hot dip galvanizing process, when these easily oxidizable elements are present as oxides on the surface, non-plating that repels hot dip plating tends to occur. Furthermore, if an easily oxidizable element is present on the surface of the steel sheet, it becomes extremely difficult to make GA because it becomes a barrier for iron diffusion from the base material in the GA process where heat treatment is performed immediately after forming hot dip galvanizing, The adhesiveness with GA is lowered, and the flaking property is deteriorated without uniform reaction. For these reasons, in the present invention, the Mn content is set to 0.03% to 3.0% and the Si content is set to 0.1% to 2.5%. Within these ranges, the surface concentration of Si and Mn and the amount of oxide formation increase, and under normal operating conditions, the GA treatment becomes difficult and the effects of the present invention are more exhibited.
［Ｓ：０．０１％以下］
Ｓは、ＭｎＳとなり、曲げ性を劣化させる。したがって、Ｓ含有量は０．０１％以下とする。
[S: 0.01% or less]
S becomes MnS and degrades bendability. Therefore, the S content is 0.01% or less.
［Ｐ：０．１％以下］
Ｐは、靱性を劣化させる好ましくない元素である。したがって、Ｐ含有量は０．１％以下とする。
[P: 0.1% or less]
P is an undesirable element that degrades toughness. Therefore, the P content is 0.1% or less.
［ｓｏｌ．Ａｌ：１．０％以下］
Ａｌは、本来、溶鋼の脱酸剤として含有されるが、Ａｌも酸化し易い元素であり、焼鈍時にＳｉやＭｎと同様、酸化物を生成し易いため、ＧＡ化処理工程において、表面性状を向上させるためには極力減らすことが望ましい。しかしながら、高強度鋼板においては、その機械的性質を確保する上においては、オーステナイトの安定化のために、積極的に含有する場合もあり、多量の含有が望まれる場合がある。
[Sol. Al: 1.0% or less]
Al is originally contained as a deoxidizer for molten steel, but Al is also an element that easily oxidizes, and, like Si and Mn, easily forms oxides during annealing. In order to improve, it is desirable to reduce as much as possible. However, in order to ensure the mechanical properties of the high-strength steel sheet, it may be actively contained in order to stabilize austenite, and a large amount may be desired.
本発明においては、Ｓｉ、Ｍｎと同様、易酸化元素であるＡｌが多量に含有される高強度鋼板における安定したＧＡ化処理を確保するとともに、良好なフレーキング性を確保するために、ｓｏｌ．Ａｌ含有量を１．０％以下とする。ｓｏｌ．Ａｌ含有量が１．０％を超えると、Ｓｉ、Ｍｎが多量に含有される場合に安定したＧＡ化処理性の確保が困難になるためである。ｓｏｌ．Ａｌ含有量の下限は特に規定するものではなく、通常のＡｌ脱酸レベルである０．０１０％以上０．１％以下はもとより、Ａｌ以外のＳｉ等の脱酸剤の使用、もしくは、その併用で、０．０１０％未満でも本発明の効果は十分得られる。 In the present invention, as in Si and Mn, in order to ensure a stable GA treatment in a high-strength steel sheet containing a large amount of easily oxidizable element Al, and to ensure good flaking properties, sol. Al content shall be 1.0% or less. sol. This is because if the Al content exceeds 1.0%, it is difficult to ensure stable GA treatment when a large amount of Si and Mn is contained. sol. The lower limit of the Al content is not particularly specified, and a normal Al deoxidation level of 0.010% or more and 0.1% or less, use of a deoxidizer such as Si other than Al, or a combination thereof Thus, even if it is less than 0.010%, the effect of the present invention is sufficiently obtained.
［Ｎ：０．０１％以下］
Ｎは、連続鋳造中に窒化物を形成してスラブのひび割れの原因となるので、Ｎ含有量は低いほうが好ましい。したがって、Ｎ含有量は０．０１％以下とする。
[N: 0.01% or less]
Since N forms a nitride during continuous casting and causes cracks in the slab, the N content is preferably low. Therefore, the N content is 0.01% or less.
次に、任意元素について説明する。
［Ｂｉ：０．０００１〜０．０５％］
Ｂｉを含有することにより、めっきの外観及び耐フレーキング性が向上する。Ｂｉ含有量が０．０００１％未満であると、上述のＢｉの効果が不十分である。一方、Ｂｉ含有量が０．０５％を超えと、結晶粒界に存在するＢｉにより粒界脆化が起こり好ましくない。好ましい範囲は０．０００３％以上０．０１％以下で、さらに好ましい範囲は０．０００３％以上０．００５０以下％である。しかしながら上記の凝固偏析をも小さくする作用を考慮した場合は、より多く含有することが好ましい。Ｂｉを添加すると前述した母材鋼板の微細な孔が増加する傾向があり、これが外観や耐フレーキング性に好影響があると考えられる。
Next, arbitrary elements will be described.
[Bi: 0.0001 to 0.05%]
By containing Bi, the appearance and anti-flaking resistance of the plating are improved. If the Bi content is less than 0.0001%, the effect of Bi described above is insufficient. On the other hand, when the Bi content exceeds 0.05%, grain boundary embrittlement occurs due to Bi existing in the crystal grain boundary, which is not preferable. A preferred range is 0.0003% to 0.01%, and a more preferred range is 0.0003% to 0.0050%. However, when considering the effect of reducing the above-mentioned solidification segregation, it is preferable to contain more. When Bi is added, the fine holes of the base steel plate tend to increase, which is considered to have a positive effect on the appearance and anti-flaking property.
なお、鋼中のＢｉは、製鋼時の凝固界面に濃化してデンドライト間隔を狭くし、凝固偏析を小さくする働きがある。その結果、偏析部での曲げ割れを防止する効果もある。これにより、めっき鋼板をプレス加工する場合に母材鋼板の割れの防止が期待でき、特に、前述したようなＭｎを多く含む鋼において有効と考えられる。 In addition, Bi in steel has a function of concentrating on a solidification interface at the time of steel making to narrow a dendrite interval and reduce solidification segregation. As a result, there is also an effect of preventing a bending crack at the segregation part. Thereby, prevention of cracking of the base steel plate can be expected when the plated steel plate is pressed, and it is considered to be particularly effective in the steel containing a large amount of Mn as described above.
［Ｔｉ：０．２５％以下、Ｎｂ：０．２５％以下、Ｖ：０．２５％以下、およびＢ：０．０１％以下からなる群から選ばれた１種または２種以上］
Ｔｉ、Ｎｂ、Ｖは、再結晶を遅らせて結晶粒を微細化させる効果を有しているので、必要に応じて含有する任意元素である。しかしながら、その効果は、Ｔｉ含有量が０．２５％を超え、Ｎｂ含有量が０．２５％を超え、Ｖ含有量が０．２５％を超えると飽和してしまいコスト的に不利となる。そのため、Ｔｉ含有量は０．２５％以下、Ｎｂ含有量は０．２５％以下、Ｖ含有量は０．２５％以下とするのが好ましい。
[One or more selected from the group consisting of Ti: 0.25% or less, Nb: 0.25% or less, V: 0.25% or less, and B: 0.01% or less]
Ti, Nb, and V are optional elements to be contained as necessary because they have the effect of delaying recrystallization and refining crystal grains. However, when the Ti content exceeds 0.25%, the Nb content exceeds 0.25%, and the V content exceeds 0.25%, the effect becomes saturated and disadvantageous in terms of cost. Therefore, the Ti content is preferably 0.25% or less, the Nb content is 0.25% or less, and the V content is preferably 0.25% or less.
ただし、例えば、９８０ＭＰａ以上の引張強度をより安定的に確保するためには、Ｔｉ、Ｎｂ、および、Ｖの何れかの元素を０．００３％以上含有させることが好ましい。
Ｂは、粒界からの核生成を抑え、焼き入れ性を高めて高強度化に寄与する元素である。したがって必要に応じて含有する任意元素である。しかし、Ｂ含有量が０．０１％を越えるとこの効果は飽和するので、Ｂ含有量は０．０１％以下とするのが好ましい。上記効果をより確実に得るためには、Ｂ含有量は０．０００５％以上であることが好ましい。
However, for example, in order to more stably secure a tensile strength of 980 MPa or more, it is preferable to contain any one element of Ti, Nb, and V in an amount of 0.003% or more.
B is an element that suppresses nucleation from the grain boundary and enhances hardenability to contribute to high strength. Therefore, it is an optional element contained as necessary. However, since this effect is saturated when the B content exceeds 0.01%, the B content is preferably 0.01% or less. In order to acquire the said effect more reliably, it is preferable that B content is 0.0005% or more.
［Ｃｒ：１％以下、Ｍｏ：１％以下、Ｃｕ：１％以下およびＮｉ：１％以下からなる群から選ばれた１種または２種以上］
Ｃｒ及びＭｏには何れもＭｎと同様にオ−ステナイトを安定化することで変態強化を促進する働きがあり、鋼板の高強度化に有効であるので必要に応じて含有する。しかし、Ｃｒ、Ｍｏも易酸化元素なので、多量の含有は好ましくない。Ｃｒ含有量が１％を超え、Ｍｏ含有量が１％を超えると加工性が低下するとともに、安定したフレーキング性、表面性状を確保することが困難となる。したがって、Ｃｒ含有量は１％以下、Ｍｏ含有量は１％以下、好ましくは、０．５％以下である。
[Cr: 1% or less, Mo: 1% or less, Cu: 1% or less, and Ni: 1% or more selected from the group consisting of 1% or less]
Both Cr and Mo have the function of promoting transformation strengthening by stabilizing austenite in the same manner as Mn, and are effective in increasing the strength of the steel sheet. However, since Cr and Mo are also easily oxidizable elements, a large amount is not preferable. When the Cr content exceeds 1% and the Mo content exceeds 1%, the workability deteriorates and it becomes difficult to ensure stable flaking properties and surface properties. Therefore, the Cr content is 1% or less, and the Mo content is 1% or less, preferably 0.5% or less.
Ｃｕ及びＮｉは、腐食抑制効果があり、表面に濃化し水素の侵入を抑え、遅れ破壊を抑制する働きがあるので、必要に応じて含有する任意元素である。しかしながら、何れもその含有量が１％を超えると前記効果は飽和しコスト的に不利となる。従って、Ｃｕ含有量もＮｉ含有量も１％以下であり、好ましくは、０．５％以下である。 Cu and Ni are corrosion-inhibiting effects, are concentrated on the surface, suppress hydrogen intrusion, and suppress delayed fracture, so are optional elements to be contained as necessary. However, in any case, if the content exceeds 1%, the effect is saturated and disadvantageous in cost. Therefore, both the Cu content and the Ni content are 1% or less, and preferably 0.5% or less.
［Ｃａ：０．０１％以下、Ｍｇ：０．０１％以下、ＲＥＭ：０．０１％以下、およびＺｒ：０．０１％以下からなる群から選ばれた１種または２種以上］
Ｃａ、Ｍｇ、ＲＥＭ、Ｚｒは、いずれも、介在物制御、特に、介在物の微細分散化に寄与し、曲げ性をさらに向上させる元素であり、必要性に応じて含有する任意元素である。しかし、過剰に含有すると表面性状を劣化させるため、それぞれの含有量を０．０１％以下とすることが好ましい。上記効果をより確実に得るためには、いずれかの元素を０．００１％以上含有させることが好ましい。
[One or more selected from the group consisting of Ca: 0.01% or less, Mg: 0.01% or less, REM: 0.01% or less, and Zr: 0.01% or less]
Ca, Mg, REM, and Zr are all elements that contribute to inclusion control, in particular, fine dispersion of inclusions and further improve bendability, and are contained as required. However, if the content is excessive, the surface properties are deteriorated, so the content is preferably 0.01% or less. In order to acquire the said effect more reliably, it is preferable to contain any element 0.001% or more.
［Ｓｂ及びＳｎのいずれか一方または双方を、ＳｂとＳｎとＢｉの合計量：０．００１〜０．０５％］
Ｓｂ、Ｓｎは、溶融亜鉛浴中に溶け出すことが期待できるので、Ｂｉと同様の効果が期待できる任意元素である。ただし、Ｂｉと同様に、素地鋼板中への偏析による粒界脆化が懸念されるので、その含有量は、０．０５％以下、複合添加する場合は、Ｓｂ、Ｓｎ、Ｂｉ併せた量が、０．０５％超にならないようにすることが好ましい。
[One or both of Sb and Sn, the total amount of Sb, Sn, and Bi: 0.001 to 0.05%]
Since Sb and Sn can be expected to dissolve in the molten zinc bath, they are arbitrary elements that can be expected to have the same effect as Bi. However, as with Bi, there is a concern about grain boundary embrittlement due to segregation in the base steel sheet, so its content is 0.05% or less. When combined, the amount of Sb, Sn, and Bi is the combined amount. It is preferable not to exceed 0.05%.
上記した以外の残部は、Ｆｅおよび不純物である。
［めっき層］
めっき層自体は、公知の合金化溶融亜鉛めっき鋼板の技術を適用すればよい。例えばめっき層中のＦｅ含有量としては７〜１５％、めっき密着性の観点からは８〜１１％が好ましい。
（Ｃ）製造方法
［還元炉内の条件］
本発明に係る製造方法は、めっき前の母材鋼板が還元焼鈍炉内の昇温時及び加熱温度保持時で鋼板温度が少なくとも６５０〜９５０℃の温度にある領域では当該焼鈍炉内の露点を−２５℃以上とし、引き続き鋼板を冷却されてからめっき浴浸漬直前までで鋼板温度が５５０℃以下の領域においては露点を−２５℃以下とすることを特徴とする。
The balance other than those described above is Fe and impurities.
[Plating layer]
For the plating layer itself, a known alloyed hot-dip galvanized steel sheet technique may be applied. For example, the Fe content in the plating layer is preferably 7 to 15%, and preferably 8 to 11% from the viewpoint of plating adhesion.
(C) Manufacturing method [Conditions in the reduction furnace]
In the manufacturing method according to the present invention, the dew point in the annealing furnace is determined in the region where the base steel sheet before plating is at a temperature of at least 650 to 950 ° C. when the heating temperature is increased and the heating temperature is maintained in the reduction annealing furnace. The dew point is set to -25 ° C or lower in the region where the steel plate temperature is 550 ° C or lower from the time when the steel plate is continuously cooled to immediately before immersion in the plating bath.
還元焼鈍炉内を図５のヒートパターンで説明する。
（１）加熱初期（〜６５０℃）
母材鋼板は、アルカリ洗浄や前処理を経た後、還元焼鈍炉で加熱される。本発明の製造方法では、前酸化炉（無酸化炉や直火炉）での母材鋼板表面の弱酸化は必須ではない。前酸化炉で弱酸化される場合は、後述するように還元焼鈍炉の高温域での露点が高いため、この温度域における鉄にとっての還元性が低露点の場合ほど強くないので、過度に酸化しないようにする。
The inside of the reduction annealing furnace will be described with reference to the heat pattern of FIG.
(1) Early heating (up to 650 ° C)
The base steel sheet is heated in a reduction annealing furnace after being subjected to alkali cleaning and pretreatment. In the production method of the present invention, weak oxidation of the surface of the base steel sheet in a pre-oxidation furnace (non-oxidation furnace or direct-fired furnace) is not essential. When it is weakly oxidized in the pre-oxidation furnace, since the dew point in the high temperature range of the reduction annealing furnace is high as described later, the reducibility for iron in this temperature range is not as strong as in the case of the low dew point, so it is excessively oxidized. Do not.
還元焼鈍炉での加熱初期（鋼板温度が６５０℃に達するまで）の領域では、加熱雰囲気は、鉄にとって還元性であればよく、特に限定されない。連続溶融亜鉛めっき設備の還元焼鈍炉の気流は、通常、下流から上流側に向かうので、この領域で特に雰囲気を制御しなければ後述する高温域での雰囲気とほぼ同様となる。 In the initial stage of heating in the reduction annealing furnace (until the steel plate temperature reaches 650 ° C.), the heating atmosphere is not particularly limited as long as it is reducible for iron. Since the air flow in the reduction annealing furnace of the continuous hot dip galvanizing equipment is usually directed from the downstream side to the upstream side, the atmosphere in the high temperature region described later is substantially the same unless the atmosphere is particularly controlled in this region.
次に６５０℃以上に加熱しさらに保持される領域では、加熱温度を高くする。
（２）高温域（６５０℃以上〜保持）
この領域では、還元焼鈍炉内の雰囲気の露点を―２５℃以上＋２０℃以下とする。なお、雰囲気ガス組成は公知のものでよく例えば１〜４０％Ｈ２でよい。これは、後述の冷却ガスあるいはそれ以降の雰囲気ガスでも同様である。露点が低すぎると、得られる合金化溶融亜鉛めっき鋼板の外観及びフレーキング性に劣る。一方、極端に高すぎる必要もなく、かえって後続の冷却以降で露点を下げるうえではあまり高すぎない方がよい。
Next, the heating temperature is increased in a region where the temperature is further maintained at 650 ° C. or higher.
(2) High temperature range (above 650 ° C or higher)
In this region, the dew point of the atmosphere in the reduction annealing furnace is set to −25 ° C. or higher and + 20 ° C. or lower. The atmospheric gas composition may be a known one, for example, 1 to 40% H 2 . The same applies to a cooling gas described later or an atmosphere gas thereafter. When the dew point is too low, the appearance and flaking property of the resulting alloyed hot-dip galvanized steel sheet are inferior. On the other hand, it is not necessary to be too high, and it is better not to be too high to lower the dew point after the subsequent cooling.
通常、純度の高い工業的なＮ２−Ｈ２混合ガスの露点は−６０℃以下なので、予め混合ガス中の露点を高めておくか、炉内に直接水蒸気を吹き込む。前者の方が、雰囲気が均質化する点で有利である。後述するように、高温域の終端付近からガスを吹き込むのがよい。 Usually, since the dew point of high purity industrial N 2 —H 2 mixed gas is −60 ° C. or less, the dew point in the mixed gas is increased in advance or steam is directly blown into the furnace. The former is advantageous in that the atmosphere is homogenized. As will be described later, the gas is preferably blown from near the end of the high temperature region.
高温域で高露点とする方が有利な理由については、次のように考える。
高Ｓｉ、Ｍｎ含有鋼がめっき性能に劣る理由は、前述したように還元焼鈍過程で母材鋼板の表面にＭｎやＳｉの酸化皮膜が形成するためである。これに対し、高温域で高露点とすると、Ｓｉ、Ｍｎにとっての酸化力が強くなり、鋼板表面に達する前に表面直下の鋼板内部で酸化され、めっきに対して影響し難くなると考えられる。前述しためっき母材界面の微細な孔は、粒状に形成されたこのようなＳｉ、Ｍｎの内部酸化物の痕跡であると考えられる。また鋼中のＢｉを適量含有することで性能が向上する理由も、前述した粒状の内部酸化物の形成が助長されるためと考えられる。
The reason why a high dew point is advantageous in a high temperature range is considered as follows.
The reason why the high Si, Mn-containing steel is inferior in plating performance is that, as described above, an oxide film of Mn or Si is formed on the surface of the base steel plate in the reduction annealing process. On the other hand, when a high dew point is set in a high temperature range, the oxidizing power for Si and Mn becomes strong, and before reaching the steel plate surface, it is oxidized inside the steel plate immediately below the surface, and it is considered that it is difficult to affect the plating. The fine holes at the plating base material interface described above are considered to be traces of the internal oxides of Si and Mn formed in a granular shape. The reason why the performance is improved by containing an appropriate amount of Bi in steel is also considered to be because the formation of the above-mentioned granular internal oxide is promoted.
（３）冷却開始から低温域（５５０℃以下）に達するまで
高温域で所定温度に保持された鋼板は、その後冷却される。このとき焼鈍炉内の雰囲気も冷却開始にあわせて、露点を下げ、低温域に達するまでに露点−２５℃以下になるようにする。なお、冷却開始後も鋼板温度６５０℃以上にある間はできるだけ露点を―２５℃以上にある方がよいが、ラインスピードが早い場合は５５０℃に下がりきる前に露点が下がることもあり、この温度域でも―２５℃となることは許容される。
(3) From the start of cooling until reaching a low temperature range (550 ° C. or lower), the steel sheet maintained at a predetermined temperature in the high temperature range is then cooled. At this time, the dew point is lowered in the annealing furnace in accordance with the start of cooling so that the dew point becomes −25 ° C. or lower before reaching the low temperature range. It is better to keep the dew point at -25 ° C or higher as long as the steel plate temperature is 650 ° C or higher even after the start of cooling. However, if the line speed is fast, the dew point may drop before it reaches 550 ° C. It is allowed to be -25 ° C even in the temperature range.
前述したように、連続溶融亜鉛めっき設備の還元焼鈍炉内の気流は通常下流から上流に向かうので、例えば、高温域終端付近で高露点ガス（あるいは水蒸気）を吹き込み、冷却帯での冷却ガスやそれ以降の領域で吹き込むガスは低露点とする。 As described above, since the air flow in the reduction annealing furnace of the continuous hot dip galvanizing equipment is usually directed from the downstream to the upstream, for example, high dew point gas (or water vapor) is blown near the end of the high temperature region, The gas blown in the area after that has a low dew point.
（４）低温域（５５０℃以下〜めっきまで）
当該領域では、焼鈍炉内の露点を−２５℃以下とする。この領域で露点が高いと、得られる合金化溶融亜鉛めっき鋼板の性能が劣化する。前述したＳｉ、Ｍｎの内部酸化物形成という点ではこの領域においても高露点の方が有利とも考えられるが、前述した界面の鋼板結晶粒内の微細孔は、この領域が高露点のときは形成されていない。この理由としては、Ｓｉ、Ｍｎだけでなく、鉄に対する酸化性−還元性とも関係する（鉄にとっての還元力が弱すぎる）ためと思われるが、詳細は不明である。
(4) Low temperature range (550 ° C or lower to plating)
In the said area | region, the dew point in an annealing furnace shall be -25 degrees C or less. If the dew point is high in this region, the performance of the resulting galvannealed steel sheet is deteriorated. In terms of the formation of internal oxides of Si and Mn as described above, it is considered that a high dew point is advantageous also in this region. However, the fine pores in the steel plate crystal grains described above are formed when this region has a high dew point. It has not been. The reason for this is considered to be related not only to Si and Mn but also to the oxidizability-reducibility to iron (the reducing power for iron is too weak), but the details are unknown.
［めっき条件］
次に、めっき浴の条件であるが、浴中のＡｌ濃度を０．０８％以上０．５％以下に調整した溶融亜鉛めっき浴に浸漬し、鋼帯の表面に亜鉛めっき層を形成する。
[Plating conditions]
Next, as a condition of the plating bath, it is immersed in a hot dip galvanizing bath in which the Al concentration in the bath is adjusted to 0.08% or more and 0.5% or less to form a galvanized layer on the surface of the steel strip.
めっき浴温度は、めっき付着量の調整を容易にするために４３０℃以上とし、Ｚｎの蒸発を避けてめっき浴の維持を容易にするために５００℃以下とすることが好ましい。鋼板のめっき浴へ侵入材温は、めっき浴の温度維持の面ではめっき浴と同程度か若干高め（＋１０℃程度）とするのがよいが、高過ぎるとドロスが発生し易くなる。 The plating bath temperature is preferably set to 430 ° C. or more for easy adjustment of the plating adhesion amount, and is preferably set to 500 ° C. or less for avoiding evaporation of Zn and facilitating maintenance of the plating bath. The temperature of the intrusion material into the plating bath of the steel sheet is preferably the same as or slightly higher than the plating bath (about + 10 ° C.) in terms of maintaining the temperature of the plating bath, but if it is too high, dross is likely to occur.
めっき浴から引き上げた後のめっき付着量の調整は、気体絞り法等、通常用いられている方法により行えばよい。めっき密着性を高める目的でめっき浴中にＡｌを添加するが、このＡｌの含有量は全めっき浴の質量に対して０．０９％以上０．５％以下が好ましい。 The adjustment of the plating adhesion amount after lifting from the plating bath may be performed by a commonly used method such as a gas drawing method. Al is added to the plating bath for the purpose of improving plating adhesion, and the content of Al is preferably 0.09% or more and 0.5% or less with respect to the mass of the entire plating bath.
本発明においてめっき付着量は特に限定されないが、高い耐食性と優れた経済性とを両立させる観点より、片面当たり１０ｇ／ｍ２以上２００ｇ／ｍ２以下とすることが好適である。 In the present invention, the plating adhesion amount is not particularly limited, but is preferably 10 g / m 2 or more and 200 g / m 2 or less per side from the viewpoint of achieving both high corrosion resistance and excellent economy.
かかる条件で、溶融亜鉛めっき皮膜を形成した後のＧＡ化であるが、本発明の目付量、および合金化度が確保できる際のＧＡ化温度は６５０℃以下である。この理由は、６５０℃超では、硬質のΓ１相が厚く形成され、耐パウダリング性が劣化するためである。一方、４５０℃未満の場合には合金化に要する時間が特に長くなり、連続処理を行うことが実質的に不可能となってしまう。 Under such conditions, the GA is formed after the hot dip galvanized film is formed. The GA forming temperature when the basis weight and the degree of alloying of the present invention can be secured is 650 ° C. or less. This is because if it exceeds 650 ° C., the hard Γ 1 phase is formed thick and the powdering resistance deteriorates. On the other hand, when the temperature is lower than 450 ° C., the time required for alloying becomes particularly long, and it is practically impossible to perform continuous processing.
そのＧＡ化の下限温度としては、本発明の合金化度を確保できる範囲内であれば、特に規定しないが、高強度鋼板の機械的性質を確保する上でもＧＡ化温度は低い程好ましい。
［その他］
連続溶融めっき設備での工程以前の母材鋼板の製造工程（すなわち、熱間圧延、冷間圧延の工程等）は、所定の機械的性質や表面性状が得られれば、特に限定されない。好ましくは、熱間圧延工程での巻き取り温度は６００℃以下が好ましい。めっきの濡れ性には高温巻き取りの方が有利だが、前述したような鋼板表層部の粒界酸化に起因してめっき密着性に悪影響を及ぼし得るためである。
The lower limit temperature of GA is not particularly limited as long as it is within the range in which the degree of alloying of the present invention can be secured, but the lower GA temperature is more preferable in order to secure the mechanical properties of the high-strength steel sheet.
[Others]
The manufacturing process of the base material steel plate before the process in the continuous hot dip plating facility (that is, the hot rolling process, the cold rolling process, etc.) is not particularly limited as long as predetermined mechanical properties and surface properties can be obtained. Preferably, the coiling temperature in the hot rolling process is preferably 600 ° C. or less. This is because high-temperature winding is more advantageous for plating wettability, but it may adversely affect plating adhesion due to the grain boundary oxidation of the steel sheet surface layer as described above.
また、得られた合金化溶融亜鉛めっき鋼板に、例えば硫酸鉄、硫酸亜鉛、リン酸亜鉛、リン酸系の水溶液による後処理を施しても何ら問題ない。 Moreover, there is no problem even if the obtained alloyed hot-dip galvanized steel sheet is subjected to post-treatment with, for example, iron sulfate, zinc sulfate, zinc phosphate, or phosphoric acid aqueous solution.
さらに、本発明を、実施例を参照しながらより具体的に説明する。
表１に示す化学組成のスラブを、１２００℃に加熱し、仕上げ熱延温度９００℃で熱間圧延を行い、水冷後、６００℃で巻き取り処理を行った。熱延鋼板の厚みは３ｍｍに統一した。次いで熱延鋼板を酸洗した後１．６ｍｍまで冷間圧延を行い、これを母材鋼板とした。
Furthermore, the present invention will be described more specifically with reference to examples.
The slab having the chemical composition shown in Table 1 was heated to 1200 ° C., hot-rolled at a final hot rolling temperature of 900 ° C., cooled with water, and then wound up at 600 ° C. The thickness of the hot-rolled steel sheet was unified to 3 mm. Next, the hot-rolled steel sheet was pickled and cold-rolled to 1.6 mm, which was used as a base steel sheet.
アルカリ処理を施した母材鋼板を、還元焼鈍炉内で、６５０℃までを平均加熱速度１５℃／秒で加熱し、引き続き６５０〜８５０℃までを５℃／秒で加熱してその後、８５０℃で５０秒間保持した。この領域での雰囲気は、Ｎ２−５％Ｈ２ガス雰囲気で露点を表２の通りとなるようにした。これには、当該保持領域終端付近から前述した加湿したガスを吹き込み調整した。 The base material steel plate subjected to the alkali treatment is heated up to 650 ° C. at an average heating rate of 15 ° C./second in a reduction annealing furnace, and subsequently heated up to 650-850 ° C. at 5 ° C./second, and then 850 ° C. Held for 50 seconds. The atmosphere in this region was N 2 -5% H 2 gas atmosphere, and the dew point was as shown in Table 2. For this, the above-mentioned humidified gas was blown and adjusted from the vicinity of the end of the holding region.
８５０℃で所定時間保持された鋼板は、平均冷却速度１０℃／秒で５００℃まで冷却された後、５００℃に６０秒間保持され、ついでさらに平均冷却速度５℃／秒で４６０℃まで冷却された。この領域の雰囲気は、ガス組成は前記と同じで、鋼板温度が保持領域において表２の露点となるようにした。これには、冷却ガスやスナウト近傍からガスを吹き込んで調整した。 The steel sheet held at 850 ° C. for a predetermined time is cooled to 500 ° C. at an average cooling rate of 10 ° C./second, then held at 500 ° C. for 60 seconds, and further cooled to 460 ° C. at an average cooling rate of 5 ° C./second. It was. The atmosphere in this region was the same as that described above, and the steel plate temperature was set to the dew point in Table 2 in the holding region. This was adjusted by blowing gas from the vicinity of the cooling gas or snout.
母材鋼板は、これに引き続き、４６０℃に調整され且つ０．１３％のＡｌが添加された溶融亜鉛めっき浴に浸漬され、付着量が調整された後、５８０℃で合金化処理された。めっきの付着量は、両面とも５０ｇ／ｍ２狙い、合金化度は８〜１１％とした。最後に、０．３％の圧下率でスキンパス圧延を行った。 Subsequent to this, the base steel sheet was immersed in a hot dip galvanizing bath adjusted to 460 ° C. and to which 0.13% of Al was added, and after the amount of adhesion was adjusted, it was alloyed at 580 ° C. The adhesion amount of plating was 50 g / m 2 on both sides, and the alloying degree was 8 to 11%. Finally, skin pass rolling was performed at a rolling reduction of 0.3%.
合金化溶融亜鉛めっき鋼板に関してはフレーキング性により評価を行った。
図６は、フレーキング性の評価試験に用いるクランクプレス機のダイスおよびパンチを模式的に示す説明図である。フレーキング性に関しては、図６に示すダイスおよびパンチを用いて、３０×１５０ｍｍの矩形サンプルを−５％のクリアランスにて縦壁部５０ｍｍのコの字成形を行い、縦壁部のテープ剥離を画像解析することによりテープへの付着物の量を定量的に解析した。フレーキング性の評価基準を下記に示す。
The alloyed hot-dip galvanized steel sheet was evaluated by flaking properties.
FIG. 6 is an explanatory diagram schematically showing a die and a punch of a crank press used for a flaking property evaluation test. Regarding the flaking property, using a die and a punch shown in FIG. 6, a rectangular sample of 30 × 150 mm is formed into a U shape with a vertical wall portion of 50 mm with a clearance of −5%, and the tape peeling of the vertical wall portion is performed. The amount of deposits on the tape was quantitatively analyzed by image analysis. Evaluation criteria for flaking properties are shown below.
［フレーキング評価方法］
◎：フレーキング率 １０％以下 ：極めて良好（合格）
○：フレーキング率 １０％超２０％以下：良好（合格）
△：フレーキング率 ２０％超３０％以下：やや不芳も実使用上問題ない（合格）
×：フレーキング率 ３０％超 ：不芳（不合格）
［めっき外観評価方法］
めっき外観に関しては、不めっきの状態をＧＩ段階での目視評価にて判断した。
[Flakeing evaluation method]
◎: Flaking rate 10% or less: Extremely good (pass)
○: Flaking rate More than 10% and 20% or less: Good (pass)
△: Flaking rate more than 20% and less than 30%: Slightly unsatisfactory but no problem in actual use (pass)
×: Flaking rate over 30%: Unsatisfactory (failed)
[Plating appearance evaluation method]
Regarding plating appearance, the state of non-plating was judged by visual evaluation at the GI stage.
最大径で、０．５ｍｍ以上の不めっきが板内で１か所以上存在している場合を評価×として、不合格とした。最大径で０．５ｍｍ未満の不めっきが発生している場合を実使用上問題なしで△（合格）とし、全くなしを○（合格）とした。 A case where at least one non-plating of 0.5 mm or more exists in the plate at the maximum diameter was evaluated as x, and was rejected. A case where non-plating with a maximum diameter of less than 0.5 mm occurred was evaluated as Δ (pass) without any problem in actual use, and none was determined as ○ (pass).
不めっきの最大径の基準は０．５ｍｍ未満であれば、亜鉛の自制防食距離から判断して、著しく防錆性が低下しないためであるが１０箇所以上は見た目状美麗で無いので×と評価した。 If the standard for the maximum diameter of non-plating is less than 0.5 mm, it is because the anticorrosion distance of zinc does not significantly reduce the rust prevention property, but it is evaluated as x because 10 or more places are not beautiful in appearance. did.
［めっき−母材界面観察方法］
前述の方法で、めっき皮膜を溶解し、ＦＥ−ＳＥＭによる観察結果から、多数の微細孔を有する結晶粒の面積率を求めた。
[Plating-base material interface observation method]
The plating film was melt | dissolved by the above-mentioned method, and the area ratio of the crystal grain which has many micropores was calculated | required from the observation result by FE-SEM.
表１および２に示すように、外観並びに密着性に優れた高強度合金化溶融亜鉛めっき鋼板の連続的な焼鈍帯と低温保持帯を有する、合金化溶融亜鉛めっきラインにおいては焼鈍露点の適正化と成分を含有することによって、自動車用の外観並びに密着性に優れた高強度合金化溶融亜鉛めっき鋼板を得られることがわかる。 As shown in Tables 1 and 2, optimization of annealing dew point in alloyed hot dip galvanizing line with continuous annealing zone and low temperature holding zone of high strength alloyed hot dip galvanized steel sheet with excellent appearance and adhesion It is understood that a high-strength galvannealed steel sheet excellent in appearance and adhesion for automobiles can be obtained by containing the above and components.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011241414A (en) * | 2010-05-14 | 2011-12-01 | Sumitomo Metal Ind Ltd | Hot dip galvanized steel sheet |
| WO2013046695A1 (en) * | 2011-09-29 | 2013-04-04 | Ｊｆｅスチール株式会社 | Hot-dip galvanized steel sheet and method for producing same |
| WO2013088666A1 (en) * | 2011-12-12 | 2013-06-20 | Ｊｆｅスチール株式会社 | High-yield-ratio high-strength cold-rolled steel sheet and method for producing same |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1046305A (en) * | 1996-07-30 | 1998-02-17 | Sumitomo Metal Ind Ltd | Galvannealed steel sheet |
| JPH1112708A (en) * | 1997-06-25 | 1999-01-19 | Kawasaki Steel Corp | Production of galvannealed dipped steel sheet |
| JP2002294397A (en) * | 2001-03-30 | 2002-10-09 | Nippon Steel Corp | High strength galvanized steel sheet having excellent plating adhesion and press formability and production method therefor |
| JP2006517257A (en) * | 2003-01-15 | 2006-07-20 | 新日本製鐵株式会社 | High strength hot dip galvanized steel sheet and method for producing the same |
| WO2007043273A1 (en) * | 2005-10-14 | 2007-04-19 | Nippon Steel Corporation | Method of continuous annealing/hot-dipping of steel sheet containing silicon and apparatus for continuous annealing/hot-dipping |
| JP2009270126A (en) * | 2008-04-08 | 2009-11-19 | Sumitomo Metal Ind Ltd | Cold rolled steel sheet, hot dip plated steel sheet and method for producing the steel sheet |
-
2010
- 2010-01-28 JP JP2010017001A patent/JP5636683B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1046305A (en) * | 1996-07-30 | 1998-02-17 | Sumitomo Metal Ind Ltd | Galvannealed steel sheet |
| JPH1112708A (en) * | 1997-06-25 | 1999-01-19 | Kawasaki Steel Corp | Production of galvannealed dipped steel sheet |
| JP2002294397A (en) * | 2001-03-30 | 2002-10-09 | Nippon Steel Corp | High strength galvanized steel sheet having excellent plating adhesion and press formability and production method therefor |
| JP2006517257A (en) * | 2003-01-15 | 2006-07-20 | 新日本製鐵株式会社 | High strength hot dip galvanized steel sheet and method for producing the same |
| WO2007043273A1 (en) * | 2005-10-14 | 2007-04-19 | Nippon Steel Corporation | Method of continuous annealing/hot-dipping of steel sheet containing silicon and apparatus for continuous annealing/hot-dipping |
| JP2009270126A (en) * | 2008-04-08 | 2009-11-19 | Sumitomo Metal Ind Ltd | Cold rolled steel sheet, hot dip plated steel sheet and method for producing the steel sheet |
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