JP3198900B2 - Manufacturing method of thin galvanized steel sheet - Google Patents
Manufacturing method of thin galvanized steel sheetInfo
- Publication number
- JP3198900B2 JP3198900B2 JP32187295A JP32187295A JP3198900B2 JP 3198900 B2 JP3198900 B2 JP 3198900B2 JP 32187295 A JP32187295 A JP 32187295A JP 32187295 A JP32187295 A JP 32187295A JP 3198900 B2 JP3198900 B2 JP 3198900B2
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- Japan
- Prior art keywords
- steel sheet
- zinc
- bath
- phase
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、薄目付けの溶融亜
鉛めっき鋼板の製造方法に係わる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thin galvanized steel sheet.
【０００２】[0002]
【従来の技術】従来、溶融亜鉛めっき鋼板の製造におい
て、めっき皮膜の付着量の制御は、鋼板を亜鉛浴に浸漬
してめっきした直後のガスワイピング（特開平０３−１
２０３４８号公報）あるいはワイピングロール（特開平
０４−２７５７号公報）により行われている。2. Description of the Related Art Conventionally, in the production of hot-dip galvanized steel sheets, the amount of plating film deposited is controlled by gas wiping immediately after the steel sheet is immersed in a zinc bath and plated.
20348) or a wiping roll (Japanese Patent Laid-Open No. 04-2775).
【０００３】[0003]
【発明が解決しようとする課題】近年、溶融亜鉛めっき
鋼板に対して、溶接性の向上、加工性の向上および価格
の低廉化への要求が強まったことから、片面当たりの付
着量が４０ｇ／ｍ2 以下ないしは３０ｇ／ｍ2 以下の溶
融亜鉛めっき鋼板を安定的にかつ生産性高く製造するこ
とが望まれている。しかし、上述のガスワイピング法と
ワイピングロール法は、めっき皮膜の付着量を薄く制御
するには、ライン速度を下げる必要があるり、生産性が
低くなる問題がある。In recent years, there has been a growing demand for hot-dip galvanized steel sheets to have improved weldability, improved workability, and reduced cost, so that the amount of adhesion per side is 40 g / side. m 2 or less or be produced stably and with high productivity to 30 g / m 2 or less of galvanized steel sheet has been desired. However, the above-described gas wiping method and wiping roll method have a problem that it is necessary to reduce the line speed or to lower the productivity in order to control the amount of coating of the plating film to be thin.
【０００４】本発明は、上記の課題を解決すべくなされ
たもので、薄目付けの溶融亜鉛めっき鋼板を安定的にか
つ生産性高く製造することができる方法を提供すること
を目的とする。[0004] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method capable of stably producing thin galvanized steel sheets with high productivity.
【０００５】[0005]
【課題を解決するための手段】上記の問題点を解決する
ための第１の本発明は、鋼板を焼鈍後冷却し，冷却した
鋼板をＡｌを含有した亜鉛浴へ浸漬して鋼板表面に亜鉛
を付着する際に，鋼板の亜鉛浴への侵入温度及び亜鉛浴
のＡｌ含有量を制御して，亜鉛浴中で鋼板表面に形成さ
れる初期合金層を微細ζ相とし、亜鉛付着量を２３．４
ｇ／ｍ ２ 以下とすることを特徴とする薄目付け溶融亜鉛
めっき鋼板の製造方法である。According to a first aspect of the present invention, a steel sheet is cooled after annealing, and the cooled steel sheet is immersed in a zinc bath containing Al to form a zinc on the steel sheet surface. when attaching, by controlling the Al content of penetration temperature and zinc bath to the zinc bath of the steel sheet, the initial alloy layer formed on the surface of the steel sheet in a zinc bath with fine ζ phase, a zinc coating weight 23.4
g / m 2 or less .
【０００６】第２の発明は、重量％で、Ｃ：０．００１
〜０．００３５％、Ｓｉ：０．１０％以下（０重量％を
含む）、Ｍｎ：０．０８〜２．５％、Ｐ：０．００５〜
０．１５％、Ｓ：０．００１〜０．０２％、Sol.Ａｌ：
０．００５〜０．１％、Ｎ：０．００３５％以下（０重
量％を含む）、Ｔｉ：０．０３〜０．１５％を含有する
鋼板を、連続溶融亜鉛めっきライン内で焼鈍後、式(3)
に示す侵入板温Ｔ℃まで冷却する工程と、侵入板温Ｔ℃
まで冷却した鋼板を，式(2)に示す範囲でＡｌを含有し
た亜鉛浴へ浸漬して亜鉛を付着させる工程と，鋼板表面
に付着した亜鉛の付着量を制御する工程とを備え，亜鉛
浴中への侵入板温Ｔ℃を浴中Ａｌ含有量との関係から式
(1) の範囲で設定して、亜鉛浴中で鋼板表面に形成され
る初期合金層の相を微細ζ相に制御し、亜鉛付着量を２
３．４ｇ／ｍ ２ 以下とすることを特徴とする薄目付け溶
融亜鉛めっき鋼板の製造方法である。[0006] The second invention is a method of the present invention, wherein C: 0.001% by weight.
0.0035%, Si: 0.10% or less (0% by weight
) , Mn: 0.08 to 2.5%, P: 0.005 to
0.15%, S: 0.001 to 0.02%, Sol. Al:
0.005 to 0.1%, N: 0.0035% or less (0 times
An amount%), Ti: a steel containing 0.03 to 0.15 percent, after annealing in a continuous galvanizing line, the formula (3)
A step of cooling to an intrusion plate temperature T ° C.
A step of immersing the steel sheet cooled down to the range shown in equation (2) into a zinc bath containing Al to deposit zinc, and a step of controlling the amount of zinc deposited on the steel sheet surface. From the relationship between the infiltration plate temperature T ° C and the Al content in the bath, the equation
By setting in the range of (1), the phase of the initial alloy layer formed on the surface of the steel sheet in the zinc bath is controlled to be a fine ζ phase, and the zinc deposition amount is 2
A method for producing a thin-coated hot-dip galvanized steel sheet, wherein the thickness is 3.4 g / m 2 or less .
【０００７】 ２９５＋９３０×Ａｌ≦Ｔ≦３３５＋９３０×Ａｌ …（１） Ａｌ≦０．２０ …（２） ３５０≦Ｔ …（３） Ｔ：侵入板温（℃）、Ａｌ：浴中Ａｌ含有量（重量％） 第３の本発明は、鋼中にさらに０．００３５％以下（０
重量％を含む）のＢを添加することを特徴とする薄目付
け溶融亜鉛めっき鋼板の製造方法である。295 + 930 × Al ≦ T ≦ 335 + 930 × Al (1) Al ≦ 0.20 (2) 350 ≦ T (3) T: penetration plate temperature (° C.), Al: Al content in bath (weight) %) In the third invention, the steel further contains 0.0035% or less (0 %).
(Including% by weight) of a hot-dip galvanized steel sheet.
【０００８】なお本発明の溶融亜鉛めっき鋼板の製造方
法は，鋼板を亜鉛浴へ浸漬して亜鉛付着量制御した後必
要により合金化処理や調質圧延を行なう方法も含まれ，
この方法で得られた合金化溶融亜鉛めっき鋼板も含まれ
る。The method for producing a hot-dip galvanized steel sheet according to the present invention includes a method in which the steel sheet is immersed in a zinc bath to control the amount of zinc applied, and then, if necessary, is subjected to alloying treatment or temper rolling.
The alloyed hot-dip galvanized steel sheet obtained by this method is also included.
【０００９】また，微細ζ相とは、長径が３μｍ未満の
ζ結晶からなる相と定義される。ζ結晶の長径の測定方
法は実施例の項で述べる。侵入板温とは、浴へ侵入する
直前の板温を指すべきであるが、設備の構造上その板温
を測定することは困難である。そこで本発明ではスナウ
トに入る直前のロール一での板温（浴から１２ｍ前の位
置）を侵入板温とした。The fine ζ phase is defined as a phase composed of か ら crystals having a major axis of less than 3 μm.測定 The method for measuring the major axis of the crystal will be described in the section of Examples. The invading plate temperature should refer to the plate temperature immediately before entering the bath, but it is difficult to measure the plate temperature due to the structure of the equipment. Therefore, in the present invention, the sheet temperature of the roll just before entering the snout (the position 12 m before the bath) was set as the intruding sheet temperature.
【００１０】[0010]
【発明の実施の形態】以下、本発明を詳細に説明する。
本発明は、以下に述べるような、溶融亜鉛めっき鋼板に
関する新しい知見に基づいている。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The present invention is based on new findings regarding a galvanized steel sheet as described below.
【００１１】第１の知見は、鋼板を亜鉛浴中に侵入させ
た時に鋼板と亜鉛浴の界面に形成されるＦｅ−Ａｌおよ
びＦｅ−Ｚｎ合金層、いわゆる初期合金層の形態は、亜
鉛浴のＡｌ濃度と亜鉛浴に侵入する際の鋼板の温度すな
わち侵入板温に依存するというものである。図１は、本
発明の成分を有する鋼（Ｔｉ系ＩＦ鋼）について、亜鉛
浴のＡｌ濃度と侵入板温と初期合金相との関係を調査し
た結果である。図１に示す通り、亜鉛浴のＡｌ濃度が低
く侵入板温が高いほど、下地鋼板の結晶粒界を起点にδ
１相が形成されたアウトバースト組織が形成される。ア
ウトバースト組織の発生領域よりも高Ａｌ濃度・低侵入
板温側の領域では、微細なζ相が形成される。更に高Ａ
ｌ濃度・低侵入板温側の領域では、粗大なζ相が形成さ
れ、更に高Ａｌ濃度・低侵入板温側の領域になると再び
微細なζ相およびＦｅＡｌ合金組織が出現する。The first finding is that the form of the Fe-Al and Fe-Zn alloy layers formed at the interface between the steel sheet and the zinc bath when the steel sheet is immersed in the zinc bath, the so-called initial alloy layer, is based on the zinc bath. It depends on the Al concentration and the temperature of the steel sheet when entering the zinc bath, that is, the temperature of the entering sheet. FIG. 1 shows the results of investigation on the relationship between the Al concentration in the zinc bath, the infiltration plate temperature, and the initial alloy phase for steel having the components of the present invention (Ti-based IF steel). As shown in FIG. 1, the lower the Al concentration in the zinc bath and the higher the intruding plate temperature, the more δ
An outburst structure in which one phase is formed is formed. A fine の phase is formed in a region having a higher Al concentration and a lower penetration temperature than the region in which the outburst structure is generated. Higher A
In the region on the 1-concentration / low-invasion plate temperature side, a coarse ζ phase is formed, and in the region on the high-Al-concentration / low-invasion plate temperature side, a fine ζ phase and a FeAl alloy structure appear again.
【００１２】第２の知見は、溶融亜鉛めっき鋼板のめっ
き付着量は、初期合金層の形態（相）に依存するという
ものである。粗大化したζ相から成る初期合金層が生成
する場合とアウトバースト組織が生成する場合は、鋼板
による溶融亜鉛の持ち上げ量が増し、ワイピング後のめ
っき付着量が増加する。これは、初期合金層が溶融亜鉛
を引き留めるアンカーの役割をしているためと推定され
る。一方、微細なζ相から成る初期合金層が生成されれ
ば、付着量は少なくなる。[0012] The second finding is that the coating weight of the hot-dip galvanized steel sheet depends on the form (phase) of the initial alloy layer. When the initial alloy layer composed of the coarse ζ phase is generated and when the outburst structure is generated, the lift of the molten zinc by the steel sheet increases, and the plating adhesion after wiping increases. This is presumably because the initial alloy layer functions as an anchor for retaining the molten zinc. On the other hand, if an initial alloy layer composed of a fine ζ phase is generated, the amount of adhesion is reduced.
【００１３】以上の知見から、本発明者らは亜鉛浴のＡ
ｌ濃度と侵入板温を適宜設定することによって初期合金
層を制御しひいては付着量を制御することができ，特
に、上記（１），（２），（３）式を満たす範囲にＡｌ
濃度と侵入板温を設定すれば、初期合金層が微細なζ相
になり、付着量を安定的かつ効果的に小さくできること
を見出だした。[0013] From the above findings, the present inventors have found that zinc bath A
By appropriately setting the l-concentration and the penetration plate temperature, it is possible to control the initial alloy layer and, consequently, control the amount of adhesion.
It has been found that if the concentration and the infiltration plate temperature are set, the initial alloy layer becomes a fine ζ phase, and the amount of adhesion can be stably and effectively reduced.
【００１４】そして，初期合金層の形態の亜鉛浴のＡｌ
濃度および侵入板温への依存性は、下地の鋼種成分によ
り異なるため、本発明では、下地鋼板を上記成分に限定
した。Then, Al in a zinc bath in the form of an initial alloy layer
Since the dependence on the concentration and the temperature of the intruding sheet differs depending on the steel type component of the base, in the present invention, the base steel sheet is limited to the above components.
【００１５】本発明の鋼は、ＴｉＩＦ鋼であり、深絞り
性に優れることを特徴としている。以下，各成分の添加
理由及び限定理由を説明する。 Ｃ：０．００１〜０．００３５％；Ｃは銑鉄中に含有さ
れ、深絞り性に悪影響を与える成分であるが、含有量を
下限未満にするためには、高度な脱炭処理が必要が必要
となり製造コストが上昇し、上限を越えると深絞り性が
悪化するため、いずれも不適当である。上限を越える場
合は、Ｃを固定するために多量のＴｉが必要となるが、
これも製造コストを上昇させる。The steel of the present invention is a TiIF steel and is characterized by having excellent deep drawability. The reasons for adding and limiting the components are described below. C: 0.001 to 0.0035%; C is a component contained in pig iron and adversely affects deep drawability, but in order to make the content less than the lower limit, advanced decarburization treatment is necessary. If it exceeds the upper limit, the production cost increases, and if it exceeds the upper limit, the deep drawability deteriorates. If the upper limit is exceeded, a large amount of Ti is required to fix C,
This also increases manufacturing costs.
【００１６】Ｓｉ：０．１０％以下；Ｓｉは上限を越え
ると皮膜のめっき性を劣化させるため、不適当である。 Ｍｎ：０．０８〜２．５０％；Ｍｎは熱間加工性を確保
するための成分であるが、下限未満では熱間脆性による
表面キズを完全に防止できず、上限を越えると深絞り性
が劣化し、いずれも不適当である。Si: 0.10% or less; If Si exceeds the upper limit, the plating property of the film is degraded, so that Si is inappropriate. Mn: 0.08 to 2.50%; Mn is a component for ensuring hot workability, but if it is less than the lower limit, surface flaws due to hot embrittlement cannot be completely prevented; Deteriorate, and all are unsuitable.
【００１７】Ｐ：０．００５〜０．１５％；Ｐは鋼板の
強度を確保するための成分であるが、下限未満では所望
の効果が得られず、上限を越えると深絞り性が劣化し、
いずれも不適当である。P: 0.005 to 0.15%; P is a component for securing the strength of the steel sheet. However, if it is less than the lower limit, the desired effect cannot be obtained, and if it exceeds the upper limit, the deep drawability deteriorates. ,
Both are inappropriate.
【００１８】Ｓ：０．００１〜０．０２％；Ｓは鋼中に
不可避不純物として含有され、熱間脆性の原因となる。
Ｔｉを添加することによってＴｉＳとして固定され、か
かる悪影響は抑制されるが、Ｔｉ添加量を減らす溜めに
は、Ｓ含有量も低い方が望ましい。上限を越えると加工
性が悪化し、下限未満にするためには高度な脱硫処理が
必要となり、製造コストが上昇するため、いずれも不適
当である。S: 0.001 to 0.02%; S is contained in steel as an unavoidable impurity and causes hot brittleness.
By adding Ti, it is fixed as TiS, and such an adverse effect is suppressed. However, it is desirable that the S content be low in order to reduce the Ti addition amount. If the upper limit is exceeded, the processability deteriorates, and if it is less than the lower limit, a high desulfurization treatment is required, and the production cost is increased.
【００１９】Sol.Ａｌ：０．００５〜０．１％；Sol.Ａ
ｌは鋼の脱酸のための成分であるが、下限未満では所望
の効果が得られず、上限を越えると効果が飽和するた
め、いずれも不適当である。Sol. Al: 0.005 to 0.1%; Sol. A
l is a component for deoxidizing steel, but if it is less than the lower limit, the desired effect cannot be obtained, and if it exceeds the upper limit, the effect is saturated, and any of them is unsuitable.
【００２０】Ｎ：０．００３５％以下；Ｎは上限を越え
ると加工性が劣化するため不適当である。 Ｔｉ：０．０３〜０．１５％；Ｔｉは鋼中のＮ，Ｓ，Ｃ
をそれぞれＴｉＮ，ＴｉＳ，ＴｉＣとして固定し、鋼の
熱間脆性を防ぐと共に、深絞り性を向上させるための成
分である。下限未満では所望の効果が得られず、上限を
越える場合は製造コストが上昇すると共にめっき性が劣
化するため、いずれも不適当である。N: 0.0035% or less; If N exceeds the upper limit, workability is deteriorated, so that N is inappropriate. Ti: 0.03 to 0.15%; Ti is N, S, C in steel
Is a component for fixing steel as TiN, TiS, and TiC, respectively, to prevent hot brittleness of steel and to improve deep drawability. If the amount is less than the lower limit, the desired effect cannot be obtained. If the amount exceeds the upper limit, the production cost is increased and the plating property is deteriorated.
【００２１】Ｂ：０．００３５％以下ＢはＴｉと同様に
鋼中のＮ，Ｓ，Ｃを固定し、鋼の熱間脆性を防ぐと共
に、深絞り性を向上させるための成分である。Ｔｉを補
うために添加するが、上限を越えると効果が飽和するた
め、不適当である。B: 0.0035% or less B is a component for fixing N, S, and C in steel similarly to Ti, preventing hot brittleness of steel and improving deep drawability. Although it is added to supplement Ti, if it exceeds the upper limit, the effect is saturated, so that it is inappropriate.
【００２２】次に製造条件の限定理由を説明する。鋼板
の焼鈍温度は常法に従い、ＡC3点以下である。侵入板温
Ｔ（℃）を（３）式の範囲（３５０≦Ｔ）とする。Next, the reasons for limiting the manufacturing conditions will be described. The annealing temperature of the steel sheet is not more than AC3 point according to a conventional method. The penetration plate temperature T (° C.) is set in the range of Expression (3) (350 ≦ T).
【００２３】下地鋼板は、ライン内で焼鈍された後、冷
却され亜鉛浴に浸漬されるため、高い生産性を維持しな
がら侵入板温を低くすることは困難である。また、低温
の鋼板を亜鉛浴に浸漬すると、浴の熱エネルギーを奪う
ことになり、製造コストが増大する。さらに、侵入板温
を低くし過ぎると、初期合金層が十分形成されず、皮膜
密着性などの品質が劣化する。以下の理由から侵入板温
は３５０℃以上に限定した。Since the base steel sheet is annealed in the line, then cooled and immersed in a zinc bath, it is difficult to lower the temperature of the intruding steel sheet while maintaining high productivity. Further, when a low-temperature steel sheet is immersed in a zinc bath, the heat energy of the bath is deprived, and the production cost increases. Further, when the intrusion plate temperature is too low, the initial alloy layer is not sufficiently formed, and the quality such as film adhesion is deteriorated. The penetration plate temperature was limited to 350 ° C. or higher for the following reasons.
【００２４】さらに，侵入板温は（１）式の範囲内とす
る。（１）式の範囲よりも高い場合は、初期合金層がア
ウトバースト組織になり付着量が増大する。また（１）
式の範囲よりも低い場合は、初期合金層が粗大なζ相に
なり、やはり付着量が増大する。さらに侵入板温が低く
なれば、再び微細なζ相が出現するが、同時に不均一な
Ｆｅ−Ａｌ合金層も形成されるため、皮膜の密着性の劣
化と合金化のムラを招く。したがって、侵入板温は
（１）式の範囲に限定した。Further, the penetration plate temperature is set within the range of the expression (1). If it is higher than the range of the expression (1), the initial alloy layer becomes an outburst structure and the amount of adhesion increases. Also (1)
If the value is lower than the range of the expression, the initial alloy layer becomes a coarse ζ phase, and the amount of adhesion also increases. When the temperature of the intrusion plate is further reduced, a fine ζ phase appears again, but at the same time, a non-uniform Fe—Al alloy layer is also formed, which leads to deterioration in adhesion of the film and uneven alloying. Therefore, the penetration plate temperature was limited to the range of the expression (1).
【００２５】亜鉛浴には、（３）式の範囲（Ａｌ≦０．
２０）でＡｌを添加する。亜鉛浴中のＡｌ濃度が０．２
０重量％を越える場合は、Ｆｅ−Ｚｎの合金化反応が起
こり難く合金化処理が困難になるとともに、製造コスト
が増大する。したがって、亜鉛浴中のＡｌ濃度は０．２
０重量％以下に限定した。In the zinc bath, the range of the formula (3) (Al ≦ 0.
In step 20), Al is added. Al concentration in zinc bath is 0.2
When the content exceeds 0% by weight, the alloying reaction of Fe-Zn hardly occurs, so that the alloying treatment becomes difficult and the production cost increases. Therefore, the Al concentration in the zinc bath is 0.2
It was limited to 0% by weight or less.
【００２６】なお，本発明では侵入板温を限定している
ので亜鉛浴の温度は特に限定されず，常法に従って４５
０℃〜４８０℃とする。浸漬処理した後，鋼板表面に付
着した亜鉛の付着量を制御する。その制御方法は，鋼板
を亜鉛浴に浸漬してめっきした直後のガスワイピングあ
るいはワイピングロールなど公知の方法を適用できる。
なお、付着量を片面当たり２３．４ｇ／ｍ 2 以下と限定
した理由は、その範囲で本発明の効果が顕著に発揮され
るためである。 In the present invention, the temperature of the zinc bath is not particularly limited since the temperature of the intruding plate is limited, and the temperature of the zinc bath is not limited.
0 ° C to 480 ° C. After the immersion treatment, the amount of zinc adhering to the steel sheet surface is controlled. As a control method, a known method such as gas wiping or wiping roll immediately after immersing a steel sheet in a zinc bath and plating it can be applied.
The reason why the amount of adhesion is limited to 23.4 g / m 2 or less per side is that the effect of the present invention is remarkably exhibited within the range .
【００２７】 このように、本発明によれば、ワイピン
グ時に鋼板とめっき皮膜の界面に形成されている初期合
金相を、微細なζ相になるように制御することにより、
ワイピングをより効果的に行えるようにし、結果とし
て、片面当たりの付着量が２３．４ｇ／ｍ 2 以下の薄目
付け溶融亜鉛めっき鋼板を、安定にかつ生産性高く製造
することが可能となる。As described above, according to the present invention, by controlling the initial alloy phase formed at the interface between the steel sheet and the plating film during wiping so as to be a fine ζ phase,
Wiping can be performed more effectively, and as a result, a thin-coated hot-dip galvanized steel sheet having an adhesion amount per side of 23.4 g / m 2 or less can be stably manufactured with high productivity.
【００２８】[0028]
【実施例】以下に本発明の実施例を示す。 （１）製造条件 表１に、本願の実施例および比較例に使用した下地鋼板
の成分を示す。表１に記載した鋼種を溶製後、熱延し、
巻き取り後に酸洗し、冷間圧延を施した後、溶融亜鉛め
っきライン内で焼鈍し、溶融亜鉛に浸漬することにより
亜鉛をめっきし、ガスワイピングを施した。その後、一
部は合金化処理を施し合金化溶融亜鉛めっき鋼板とし、
残りは合金化処理を施さずに溶融亜鉛めっき鋼板とし
た。表２に実施例および比較例に共通の製造条件を示
す。表３に本発明の実施例を示す。また、表４、表５に
比較例を示す。ここで、表３〜表５の初期合金層の相の
欄に記載の微細ζは微細ζ相（結晶の長径が３μｍ未
満），粗大ζは粗大ζ相（結晶の長径が３μｍ以上）、
ＯＢはアウトバースト組織を示している。Examples of the present invention will be described below. (1) Manufacturing conditions Table 1 shows the components of the base steel sheet used in the examples and comparative examples of the present application. After smelting the steel types listed in Table 1, hot rolling,
After being taken up, it was pickled, cold-rolled, annealed in a hot-dip galvanizing line, immersed in molten zinc, plated with zinc, and subjected to gas wiping. After that, a part is subjected to alloying treatment to make an alloyed hot-dip galvanized steel sheet,
The remainder was a hot-dip galvanized steel sheet without performing alloying treatment. Table 2 shows manufacturing conditions common to the examples and the comparative examples. Table 3 shows examples of the present invention. Tables 4 and 5 show comparative examples. Here, in the column of the phase of the initial alloy layer in Tables 3 to 5, fine ζ indicates a fine ζ phase (the major axis of the crystal is less than 3 μm), coarse ζ indicates a coarse ζ phase (the major axis of the crystal is 3 μm or more),
OB indicates an outburst tissue.
【００２９】表１に記載した鋼板成分の分析値はＩＣＰ
による分析値である。表３および表４、表５に記載した
浴中Ａｌ濃度は、浴から採取した試験片をＩＣＰで分析
した値である。The analysis values of the steel sheet components described in Table 1 are obtained by ICP.
It is the analysis value by. The Al concentration in the bath described in Table 3, Table 4, and Table 5 is a value obtained by analyzing a test piece taken from the bath by ICP.
【００３０】（２）初期合金層の観察 表３および表４、表５に記載した実施例および比較例の
うち、合金化処理を施さないものについては、初期合金
層の観察を行った。初期合金層の観察は、ＳＥＭにより
行われた。作製した溶融亜鉛めっき鋼板の、幅方向に端
から４分の１、中央、４分の３の位置のそれぞれ表裏、
合計６ヶ所から試験片を切り出し、めっき皮膜を塩酸で
溶解させて初期合金層を露出させた後、ＳＥＭで真上か
ら１５００倍の倍率で観察し、最も大きな面積を占める
相をこのめっき鋼板の初期合金相とした。また、観察さ
れた範囲で最も大きな結晶の長径を初期合金層の結晶粒
径とした。(2) Observation of the initial alloy layer Of the examples and comparative examples described in Tables 3, 4 and 5 where no alloying treatment was performed, the initial alloy layer was observed. The observation of the initial alloy layer was performed by SEM. Front and back at the position of 1/4, the center, and 3/4 from the end in the width direction of the prepared hot-dip galvanized steel sheet,
Test pieces were cut out from a total of six locations, the plating film was dissolved with hydrochloric acid to expose the initial alloy layer, and observed by SEM at a magnification of 1500 times directly above, and the phase occupying the largest area of this plated steel sheet was determined. It was an initial alloy phase. The longest diameter of the largest crystal in the observed range was defined as the crystal grain size of the initial alloy layer.
【００３１】（３）付着量の測定 付着量の測定は、皮膜を塩酸で溶解させ、その前後の重
量差を測定することによって行われた。表３および表
４、表５に記載した付着量の値は、試験片の幅方向に端
から４分の１、中央、４分の３の位置のそれぞれ表裏、
合計６ヶ所の平均値である。(3) Measurement of adhesion amount The adhesion amount was measured by dissolving the film with hydrochloric acid and measuring the weight difference before and after the dissolution. The values of the adhesion amounts described in Tables 3 and 4 and Table 5 are, respectively, the front, back, and center of the test specimen in the width direction at the quarter, center, and quarter positions, respectively.
These are the average values of a total of six locations.
【００３２】（４）比較例 比較例のＮｏ．１，２，５，６，９，１０，１３，１
４，１７，１８，２１，２２，２５，２６，２９，３
０，３３，３４は、侵入板温が（１）式の設定よりも低
いため、初期合金層が粗大なζ相になり、付着量が増大
する。(4) Comparative Example No. of Comparative Example 1,2,5,6,9,10,13,1
4,17,18,21,22,25,26,29,3
In Nos. 0, 33, and 34, since the penetration plate temperature is lower than the setting of the expression (1), the initial alloy layer becomes a coarse ζ phase and the amount of adhesion increases.
【００３３】Ｎｏ．４３，４４，４７，４８，５１，５
２，５５，５６，５９，６０，６３，６４，６７，６
８，７１，７２，７５，７６も、めっき後に合金化して
いるため初期合金層は観察できないが、同じ理由で付着
量が増大すると考えられる。No. 43,44,47,48,51,5
2,55,56,59,60,63,64,67,6
8, 71, 72, 75, and 76 also cannot be observed in the initial alloy layer because they are alloyed after plating, but it is considered that the adhesion amount increases for the same reason.
【００３４】Ｎｏ．３，４，７，８，１１，１２，１
５，１６，１９，２０，２３，２４，２７，２８，３
１，３２，３５，３６は、侵入板温が（１）式の設定よ
りも高いため、初期合金層がアウトバースト組織になり
付着量が増大する。No. 3,4,7,8,11,12,1
5,16,19,20,23,24,27,28,3
In Nos. 1, 32, 35 and 36, since the penetration plate temperature is higher than the setting of the expression (1), the initial alloy layer becomes an outburst structure and the amount of adhesion increases.
【００３５】Ｎｏ．４５，４６，４９，５０，５３，５
４，５７，５８，６１，６２，６５，６６，６９，７
０，７３，７４，７７，７８も、めっき後に合金化して
いるため初期合金層は観察できないが、同じ理由で付着
量が増大すると考えられる。Ｎｏ．３７〜４２，７９〜
８４は、下地鋼板の成分が本発明の限定範囲を外れてい
るため付着量が増大する。No. 45, 46, 49, 50, 53, 5
4,57,58,61,62,65,66,69,7
Also in Nos. 0, 73, 74, 77, and 78, the initial alloy layer cannot be observed because they are alloyed after plating, but it is considered that the amount of adhesion increases for the same reason. No. 37-42, 79-
In No. 84, the amount of adhesion increases because the components of the base steel sheet are outside the limited range of the present invention.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 [Table 2]
【００３８】[0038]
【表３】 [Table 3]
【００３９】[0039]
【表４】 [Table 4]
【００４０】[0040]
【表５】 [Table 5]
【００４１】[0041]
【発明の効果】以上の結果から明らかなように、溶融亜
鉛めっきラインにおける鋼板の侵入板温を、浴中のＡｌ
濃度に応じて制御することにより、初期合金相を制御
し、ひいては付着量を制御することができる。特に、浴
中Ａｌ濃度と侵入板温を（１），（２），（３）式を満
たす範囲に設定した場合は、ワイピング条件が同じであ
れば、浴中Ａｌ濃度と侵入板温を他の範囲に設定した場
合に比べて、めっきの付着量を少なくすることができ
る。したがって、本発明により薄目付けの溶融亜鉛めっ
き鋼板を安定的にかつ生産性高く製造することができ
る。As is evident from the above results, the penetration sheet temperature of the steel sheet in the hot-dip galvanizing line was determined by changing the Al temperature in the bath.
By controlling in accordance with the concentration, the initial alloy phase can be controlled, and thus the amount of adhesion can be controlled. In particular, when the Al concentration in the bath and the penetration plate temperature are set in a range satisfying the equations (1), (2), and (3), if the wiping conditions are the same, the Al concentration in the bath and the penetration plate temperature are changed. The amount of plating can be reduced as compared with the case where the above range is set. Therefore, according to the present invention, a thin galvanized steel sheet can be stably manufactured with high productivity.
【図１】本発明の亜鉛浴のＡｌ濃度と侵入板温の範囲を
示す図。横軸が浴中Ａｌ含有量（重量％）、縦軸が侵入
板温（℃）で、斜線部が本発明の範囲である。FIG. 1 is a diagram showing the range of the Al concentration and the penetration plate temperature of a zinc bath of the present invention. The horizontal axis is the Al content (% by weight) in the bath, the vertical axis is the penetration plate temperature (° C.), and the shaded area is the range of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山下 敬士 東京都千代田区丸の内一丁目１番２号 日本鋼管株式会社内 (56)参考文献 特開 平４−103749（ＪＰ，Ａ) 特開 平４−103748（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C23C 2/00 - 2/40 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Keishi Yamashita 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP-A-4-103749 (JP, A) JP-A-4 −103748 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C23C 2/00-2/40
Claims (3)
ｌを含有した亜鉛浴へ浸漬して鋼板表面に亜鉛を付着す
る際に，鋼板の亜鉛浴への侵入温度及び亜鉛浴のＡｌ含
有量を制御して，亜鉛浴中で鋼板表面に形成される初期
合金層を微細ζ相とし、亜鉛付着量を２３．４ｇ／ｍ ２
以下とすることを特徴とする薄目付け溶融亜鉛めっき鋼
板の製造方法。1. A steel sheet is cooled after annealing, and the cooled steel sheet is
When zinc is immersed in a zinc bath containing l, the zinc is formed on the surface of the steel plate in the zinc bath by controlling the penetration temperature of the steel plate into the zinc bath and the Al content of the zinc bath. the initial alloy layer with fine ζ phase, 23.4 g of zinc deposition amount / m 2
A method for producing a thin-coated hot-dip galvanized steel sheet, characterized in that :
５％、Ｓｉ：０．１０％以下（０重量％を含む）、Ｍ
ｎ：０．０８〜２．５％、Ｐ：０．００５〜０．１５
％、Ｓ：０．００１〜０．０２％、Sol.Ａｌ：０．００
５〜０．１％、Ｎ：０．００３５％以下（０重量％を含
む）、Ｔｉ：０．０３〜０．１５％を含有する鋼板を、
連続溶融亜鉛めっきライン内で焼鈍後、式(3) に示す侵
入板温Ｔ℃まで冷却する工程と、侵入板温Ｔ℃まで冷却
した鋼板を，式(2) に示す範囲でＡｌを含有した亜鉛浴
へ浸漬して亜鉛を付着させる工程と，鋼板表面に付着し
た亜鉛の付着量を制御する工程とを備え，亜鉛浴中への
侵入板温Ｔ℃を浴中Ａｌ含有量との関係から式(1) の範
囲で設定して、亜鉛浴中で鋼板表面に形成される初期合
金層の相を微細ζ相に制御し、亜鉛付着量を２３．４ｇ
／ｍ ２ 以下とすることを特徴とする薄目付け溶融亜鉛め
っき鋼板の製造方法。 ２９５＋９３０×Ａｌ≦Ｔ≦３３５＋９３０×Ａｌ (1) Ａｌ≦０．２０ (2) ３５０≦Ｔ (3) Ｔ：侵入板温（℃）、Ａｌ：浴中Ａｌ含有量（重量％）2. C: 0.001 to 0.003 by weight%
5%, Si: 0.10% or less (including 0% by weight) , M
n: 0.08 to 2.5%, P: 0.005 to 0.15
%, S: 0.001 to 0.02%, Sol. Al: 0.00
5 to 0.1%, N: 0.0035% or less (including 0% by weight)
E ) a steel sheet containing 0.03 to 0.15% Ti:
After annealing in a continuous hot-dip galvanizing line, a step of cooling to an intruding sheet temperature T ° C. shown in equation (3), A step of immersing the zinc in the zinc bath to deposit zinc and a step of controlling the amount of zinc deposited on the surface of the steel sheet. The phase of the initial alloy layer formed on the surface of the steel sheet in the zinc bath is controlled to a fine ζ phase by setting within the range of the formula (1), and the zinc deposition amount is 23.4 g.
/ M 2 or less, a method for producing a thin-coated hot-dip galvanized steel sheet. 295 + 930 × Al ≦ T ≦ 335 + 930 × Al (1) Al ≦ 0.20 (2) 350 ≦ T (3) T: penetration plate temperature (° C.), Al: Al content in bath (% by weight)
含む）のＢを添加することを特徴とする請求項２に記載
の薄目付け溶融亜鉛めっき鋼板の製造方法。3% or less (0% by weight ) in steel
Method for manufacturing a thin with hot-dip galvanized steel sheet according to claim 2, characterized in that the addition of B of including).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32187295A JP3198900B2 (en) | 1995-12-11 | 1995-12-11 | Manufacturing method of thin galvanized steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32187295A JP3198900B2 (en) | 1995-12-11 | 1995-12-11 | Manufacturing method of thin galvanized steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09157817A JPH09157817A (en) | 1997-06-17 |
| JP3198900B2 true JP3198900B2 (en) | 2001-08-13 |
Family
ID=18137351
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| CN103627957B (en) * | 2013-10-14 | 2016-03-30 | 首钢总公司 | The production method of CR4 hot dip galvanizing automobile plate steel |
| CN104911522B (en) * | 2015-06-09 | 2017-10-31 | 武汉钢铁有限公司 | A kind of method of wire galvanization |
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| Publication number | Publication date |
|---|---|
| JPH09157817A (en) | 1997-06-17 |
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