JPH10265925A - Production of galvannealed steel sheet excellent in plating adhesion - Google Patents
Production of galvannealed steel sheet excellent in plating adhesionInfo
- Publication number
- JPH10265925A JPH10265925A JP7315297A JP7315297A JPH10265925A JP H10265925 A JPH10265925 A JP H10265925A JP 7315297 A JP7315297 A JP 7315297A JP 7315297 A JP7315297 A JP 7315297A JP H10265925 A JPH10265925 A JP H10265925A
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- steel sheet
- temp
- hot
- temperature
- plating
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、めっき密着性に優
れた合金化溶融亜鉛めっき鋼板の製造方法に関し、特に
自動車用防錆鋼板として多用されている鋼板の製造技術
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a galvannealed steel sheet having excellent plating adhesion, and more particularly to a technique for producing a steel sheet frequently used as a rust-preventive steel sheet for automobiles.
【０００２】[0002]
【従来の技術】現在、自動車用防錆鋼板としては、優れ
た犠牲防食能の観点から亜鉛系の溶融めっき、あるいは
電気めっき鋼板が開発され、実用化されている。なかで
も、合金化溶融亜鉛めっき鋼板は、製造コストが低廉で
且つ高耐食性を有するので、亜鉛系のめっき鋼板のうち
でも特に実車に多用されている。しかしながら、合金化
溶融亜鉛めっき鋼板は、鋼板に溶融亜鉛めっきを施した
後、通常５００℃近傍の温度域で合金化処理を施し、地
鉄とめっき層である亜鉛との相互拡散によって両者の界
面にＺｎ−Ｆｅの金属間化合物を生成させて製造するた
め、電気めっきを施した亜鉛めっき鋼板に比較して、本
質的にめっき層と鋼板との密着性が悪いという問題を有
している。2. Description of the Related Art At present, zinc-based hot-dip or electroplated steel sheets have been developed and put into practical use as rust-resistant steel sheets for automobiles from the viewpoint of excellent sacrificial corrosion protection. Above all, galvannealed steel sheets are inexpensive to manufacture and have high corrosion resistance, and are therefore frequently used in actual vehicles among zinc-based coated steel sheets. However, alloyed hot-dip galvanized steel sheets, after hot-dip galvanizing the steel sheet, are usually subjected to alloying treatment at a temperature in the vicinity of 500 ° C., and the interface between the two by interdiffusion between the ground iron and the zinc, which is the plating layer. In addition, the method has a problem that the adhesion between the plating layer and the steel sheet is essentially lower than that of the galvanized steel sheet which has been subjected to electroplating, since it is produced by producing an intermetallic compound of Zn-Fe.
【０００３】そのため、溶融亜鉛めっき、あるいは合金
化溶融亜鉛めっき鋼板を製造する場合には、めっき浴中
に適当量のＡｌを添加し、前記密着性を改善する方策が
考えられ、現在生産されている亜鉛系溶融亜鉛めっき鋼
板は、通常、Ａｌ含有亜鉛浴を用いて製造されている。
しかしながら、上記の方策のみでは、自動車用鋼板とし
て要求されているめっき層の密着性を常に確保するには
不十分であり、例えば溶融亜鉛めっき浴内のＡｌ濃度の
厳密な管理、合金化温度の適正化などが行われている。
さらに、最近では、特開平１−２７９７３８号公報に目
付制御完了後合金化炉内の昇温過程で４７０℃以上の板
温に到達する間での時間が２．０秒以下の急速加熱を施
し、合金化完了後は冷却過程において板温度が４２０℃
以下の温度域まで２秒以下で急速冷却することが開示さ
れており、合金化時の急速加熱、急速冷却により良好な
密着性を確保しようとする技術が提案されている。[0003] Therefore, when manufacturing a hot-dip galvanized or alloyed hot-dip galvanized steel sheet, a measure to improve the adhesion by adding an appropriate amount of Al to a plating bath is considered. Some zinc-based hot-dip galvanized steel sheets are usually manufactured using an Al-containing zinc bath.
However, the above measures alone are not sufficient to always ensure the adhesion of the plating layer required as a steel sheet for automobiles, for example, strict control of the Al concentration in the hot-dip galvanizing bath, and control of the alloying temperature. Optimization has been carried out.
Furthermore, recently, in Japanese Unexamined Patent Publication No. 1-279738, rapid heating is performed for 2.0 seconds or less until the sheet temperature reaches 470 ° C. or more in the course of temperature rise in the alloying furnace after the completion of the weight control. After the completion of alloying, the plate temperature is 420 ° C in the cooling process
It is disclosed that rapid cooling is performed to the following temperature range in 2 seconds or less, and a technique for securing good adhesion by rapid heating and rapid cooling during alloying has been proposed.
【０００４】[0004]
【発明が解決しようとする課題】合金化溶融亜鉛めっき
鋼板の場合、既往の研究によって、めっき層の密着性と
めっきの相構造との間には密接な関係があること、つま
り鋼板と地鉄との界面に形成される鉄含有率の高い金属
間化合物Г相の存在量が多くなると、密着性が劣化して
くることが知られている。先にも述べたように、合金化
溶融亜鉛めっき鋼板でのめっき層は、亜鉛めっき層と鋼
板との相互拡散により形成されるので、通常の方法で
は、めっき浴にＡｌが存在していても、めっき層と鋼板
との界面に不可避的にГ相が生成してしまう。さらに、
合金化温度や合金化時の加熱速度、冷却速度等の合金化
条件の適正化を行い、Г相生成をある程度まで抑制可能
であるとしても、その生成を完全に抑制することができ
ない。従って、製品鋼板のめっき密着性も相対的には良
好になるが、十分な水準に到達したとは言い難い。In the case of alloyed hot-dip galvanized steel sheets, previous studies have shown that there is a close relationship between the adhesion of the coating layer and the phase structure of the plating. It is known that, when the abundance of the intermetallic compound Г phase having a high iron content formed at the interface with, increases, the adhesiveness deteriorates. As described above, the plating layer in the alloyed hot-dip galvanized steel sheet is formed by interdiffusion between the galvanized layer and the steel sheet, and therefore, in a normal method, even if Al is present in the plating bath. As a result, a Г phase is inevitably generated at the interface between the plating layer and the steel sheet. further,
Even if the alloying conditions such as the alloying temperature, the heating rate during alloying, and the cooling rate are optimized and the Г phase formation can be suppressed to some extent, the formation cannot be completely suppressed. Therefore, although the plating adhesion of the product steel sheet is relatively good, it cannot be said that it has reached a sufficient level.
【０００５】本発明は、かかる事情に鑑み、従来よりも
一層めっき密着性に優れた合金化溶融亜鉛めっき鋼板を
製造する方法を提供することを目的とする。[0005] In view of such circumstances, an object of the present invention is to provide a method for producing an alloyed hot-dip galvanized steel sheet having more excellent plating adhesion than before.
【０００６】[0006]
【課題を解決するための手段】発明者らは、上記目的を
達成するため鋭意研究を重ね、優れためっき密着性を有
する合金化溶融亜鉛めっき鋼板を製造するには、めっき
後だけの対策では限界があり、めっき前の鋼板性状を適
正化することによって密着性の飛躍的な向上が可能であ
ることを見出した。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object, and in order to produce an alloyed hot-dip galvanized steel sheet having excellent plating adhesion, it is necessary to take measures only after plating. There is a limit, and it has been found that the adhesion can be dramatically improved by optimizing the properties of the steel sheet before plating.
【０００７】すなわち、本発明は、合金化溶融亜鉛めっ
き鋼板の製造にあたり、素材となる鋼板の熱間圧延時の
巻取温度を６００℃以上とし、溶融めっき後、３０℃／
ｓｅｃ以上の昇温速度で４７０〜５１０℃まで昇温しこ
の温度域に保持する合金化処理を行い、鉄含有率８〜１
１ｗｔ％のＺｎ−Ｆｅ合金めっき層を得ることを特徴と
するめっき密着性に優れた合金化溶融亜鉛めっき鋼板の
製造方法を提供する。この場合、さらに、合金化処理
後、４２０℃まで３０℃／ｓｅｃ以上の冷却速度で冷却
することとすれば、さらにめっき密着性を向上させるこ
とができ好ましい。That is, according to the present invention, in producing an alloyed hot-dip galvanized steel sheet, the winding temperature of the steel sheet as a raw material during hot rolling is set to 600 ° C. or more, and after hot-dip galvanizing, 30 ° C. /
An alloying treatment was performed by raising the temperature to 470 to 510 ° C. at a rate of temperature increase of at least sec and maintaining the temperature in this temperature range, and the iron content was 8 to 1
Provided is a method for producing an alloyed hot-dip galvanized steel sheet having excellent plating adhesion, characterized by obtaining a 1 wt% Zn-Fe alloy plating layer. In this case, it is preferable to further cool to 420 ° C. at a cooling rate of 30 ° C./sec or more after the alloying treatment because the plating adhesion can be further improved.
【０００８】本発明では、素材となる鋼板の巻き取り温
度を限定し、これとめっき層合金化時の昇温速度とを組
合わせ、さらに合金化後の冷却速度の規定も付加したの
で、合金化時にΓ相の出現を抑えることができる。その
結果、めっき中の鉄含有率の管理と併せ、従来より著し
く優れためっき密着性を有する合金化溶融亜鉛めっき鋼
板を製造することが可能になった。In the present invention, the winding temperature of the steel sheet as the raw material is limited, this is combined with the heating rate during the alloying of the plating layer, and the cooling rate after the alloying is also specified. The appearance of Γ phase can be suppressed at the time of formation. As a result, it has become possible to manufacture an alloyed hot-dip galvanized steel sheet having significantly superior plating adhesion as well as controlling the iron content during plating.
【０００９】[0009]
【発明の実施の形態】以下に本発明をさらに詳細に説明
する。上述のように、合金化溶融亜鉛めっき鋼板の良好
な密着性を確保するためには、合金化処理時にめっき層
と鋼板との界面に現れるГ相を極力抑制することが必要
である。発明者は、まずこのГ相量と合金化条件との関
係について調査し、以下のように、合金化溶融亜鉛めっ
き鋼板について優れた密着性を得る合金化条件を見出し
た。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. As described above, in order to ensure good adhesion of the alloyed hot-dip galvanized steel sheet, it is necessary to minimize the Г phase that appears at the interface between the plated layer and the steel sheet during the alloying treatment. The inventor first investigated the relationship between the amount of the Г phase and the alloying conditions, and found out the alloying conditions for obtaining excellent adhesion to the galvannealed steel sheet as described below.
【００１０】合金化温度に関しては、めっき浴を出た時
の板温を４７０〜５１０℃の範囲に昇温、保持すること
が必要条件であり、望ましくは４８０〜４９０℃の範囲
での合金化が必要となる。４７０〜５１０℃以外の温度
範囲における合金化では、昇温速度等の他の条件を変え
ても良好な密着性を得ることは困難である。４７０℃未
満の温度で合金化すると、めっき表相にζ相が生成しや
すくなる。ζ相は鉄の固溶限が少ないため、ζ相がＺｎ
−Ｆｅ合金層表面に存在すると、δ1 単相の場合に比較
して地鉄からの鉄の拡散が抑制され、結果的に界面の鉄
含有率が上昇してГ相が生成しやすくなる。ζ相のめっ
き表面での出現は、Г相生成を助長するのみならず、他
の性能への影響、例えばプレス加工時のフレーキング性
の劣化、摺動性の劣化などという観点からも不利とな
る。また、合金化温度が５１０℃を超えるような高温に
なると、Г相が生成しやすくなることは状態図上からも
明らかであり、合金化温度は５１０℃を超えてはいけな
い。[0010] With respect to the alloying temperature, it is necessary to raise and maintain the sheet temperature at the time of leaving the plating bath in the range of 470 to 510 ° C, preferably in the range of 480 to 490 ° C. Is required. In alloying in a temperature range other than 470 to 510 ° C., it is difficult to obtain good adhesion even if other conditions such as a heating rate are changed. When the alloy is formed at a temperature lower than 470 ° C., a ζ phase is easily generated in the surface phase of the plating. Since the ζ phase has a small solid solubility limit of iron,
When present in -Fe alloy layer surface, the diffusion of iron suppression from base steel as compared to the case of [delta] 1 Single-phase, resulting in surface iron content of is Г phase is likely to generate elevated. The appearance of the ζ phase on the plating surface not only promotes the 生成 phase formation, but is disadvantageous from the viewpoint of affecting other performance, such as deterioration of flaking property during press working and deterioration of slidability. Become. It is also clear from the phase diagram that the Г phase is likely to be formed when the alloying temperature is higher than 510 ° C., and the alloying temperature should not exceed 510 ° C.
【００１１】本発明では、合金化処理を上記温度範囲で
行うようにしたが、Г相の抑制にはめっき層中の鉄含有
率の調整も極めて重要であり、合金化溶融亜鉛めっき鋼
板製造後のめっき中の鉄含有率を８〜１１ｗｔ％に管理
する必要がある。鉄含有率を上記範囲とするのは、鉄含
有率が８ｗｔ％未満ではめっき表層に未合金のη相が残
存し、耐食性、塗膜密着性等の諸性能に悪影響を与える
ためであり、また、１１ｗｔ％を超えると、めっき層と
鋼板との界面にГ相が多量に生成するようになり、良好
な密着性を確保するのが困難となるためである。このめ
っき中の鉄含有率は主としてめっき厚さ、合金化処理温
度及び処理時間に支配される。合金化温度が４７０〜５
１０℃の範囲内では合金化処理時間は１０〜２０ｓｅｃ
が適切である。合金化処理時間が３０ｓｅｃ以上になる
と鉄含有量が１１ｗｔ％を越えるので好ましくない。以
上のように、密着性の良好な合金化溶融亜鉛めっき鋼板
の製造のためには、合金化処理時間の適正な調整等によ
って、鉄含有率を上記範囲内にすることが必要である。In the present invention, the alloying treatment is performed within the above-mentioned temperature range. However, it is also very important to control the iron content in the coating layer for suppressing the Г phase. It is necessary to control the iron content during plating to 8 to 11 wt%. If the iron content is within the above range, when the iron content is less than 8 wt%, an unalloyed η phase remains on the plating surface layer, which adversely affects various properties such as corrosion resistance and coating film adhesion. If it exceeds 11 wt%, a large amount of Г phase will be generated at the interface between the plating layer and the steel sheet, and it will be difficult to ensure good adhesion. The iron content in the plating is mainly governed by the plating thickness, the alloying treatment temperature and the treatment time. Alloying temperature of 470-5
In the range of 10 ° C., the alloying treatment time is 10 to 20 sec.
Is appropriate. If the alloying treatment time is longer than 30 sec, the iron content exceeds 11 wt%, which is not preferable. As described above, in order to produce an alloyed hot-dip galvanized steel sheet having good adhesion, it is necessary to keep the iron content within the above range by appropriately adjusting the alloying treatment time.
【００１２】次に、発明者は、めっき密着性に大きな影
響を与える条件として、合金化時の昇温速度、冷却速度
をある値以上にして高速昇温、高速冷却することが必要
であることも見出した。昇温速度としては、めっきに引
き続いて行われる付着量の調整後、合金化温度への昇温
時に３０℃／ｓｅｃ以上の昇温速度で加熱することによ
って、合金化時のГ相生成を極力抑制することが可能と
なる。この理由は、次の通りである。すなわち、合金化
時の昇温速度が低い場合、ζ相が生成しやすい４７０℃
未満の低温領域に滞留する時間が長くなり、ζ相が生成
した状態で合金化が進行し、先に述べたのと同様の理由
からめっき層と鋼板との界面にГ相が生成しやすくなる
ためである。また、合金化が良好に終了しても、冷却速
度が十分に速くないと、ζ相が生成し易くなる。つま
り、ζ相が存在しうる温度領域を長時間通ることになる
ので、δ1 相からζ相への変態が起こり、先に述べたの
と同様の理由からГ相が生成しやすくなるのである。よ
って、合金化時の冷却速度に関しても、３０℃／ｓｅｃ
以上という大きい冷却速度で冷却することが望ましい。Next, the inventor has stated that as a condition that greatly affects the plating adhesion, it is necessary to raise the temperature and cooling rate during alloying to a certain value or more, and to perform high-speed heating and high-speed cooling. Also found. As the heating rate, after adjusting the amount of deposition performed following plating, heating at a heating rate of 30 ° C./sec or more at the time of heating to the alloying temperature minimizes the Г phase generation during alloying. It becomes possible to suppress. The reason is as follows. That is, when the rate of temperature rise during alloying is low, the ζ phase is likely to be generated at 470 ° C.
The residence time in the low-temperature region of less than becomes longer, alloying proceeds in a state where the ζ phase is generated, and the Г phase is easily generated at the interface between the plating layer and the steel sheet for the same reason as described above. That's why. Further, even if alloying is successfully completed, if the cooling rate is not sufficiently high, a ζ phase is likely to be generated. In other words, since it passes through the temperature region where the ζ phase can exist for a long time, the transformation from the δ 1 phase to the ζ phase occurs, and the Г phase is easily generated for the same reason as described above. . Therefore, the cooling rate during alloying is also 30 ° C./sec.
It is desirable to cool at the above-mentioned high cooling rate.
【００１３】さて、これまで記した合金化時の昇温速
度、冷却速度だけを規定しただけでは十分な密着性を確
保するには、まだ不十分であった。そこで、発明者は、
めっき前の鋼板性状を最適化することに着眼し、これを
上述の合金化時の昇温速度、冷却速度と組合せることに
よって、密着性を格段に向上させることができることを
見出した。ここでいう鋼板性状の最適化は、熱間圧延時
にある温度以上で鋼板を巻き取ることによって可能とな
る。すなわち６００℃以上の温度で巻き取ることによ
り、合金化亜鉛めっき鋼板の密着性が格段に向上するこ
とが明らかになった。その理由は次のとおりと考えられ
る。熱間圧延時の鋼板の巻き取り温度を６００℃以上と
すると熱間圧延時に生成される鉄系酸化物層の下に粒界
酸化層が形成される。この粒界酸化層は冷間圧延後も、
鋼板表層に酸化物を分散した形で存在する。この粒界酸
化層は鋼中成分として添加されているＭｎ等の合金元素
が溶融亜鉛めっき製造工程における焼鈍時または昇温時
に表面濃化するのを著しく抑制し、引き続いて行われる
合金化処理時に鉄の拡散速度を向上させる作用を持つ。
よって上記理由により、熱間圧延時の巻き取り温度を規
定することにより全体的に合金化速度が早くなり、上述
の合金化処理時の昇温速度を上げる効果がさらに有効と
なる。By the way, it has not been enough to secure sufficient adhesiveness only by specifying the heating rate and the cooling rate during the alloying described above. Therefore, the inventor
Focusing on optimizing the properties of the steel sheet before plating, it has been found that by combining this with the above-mentioned heating rate and cooling rate during alloying, the adhesion can be significantly improved. The optimization of the properties of the steel sheet can be made by winding the steel sheet at a certain temperature or higher during hot rolling. That is, it has been clarified that by winding at a temperature of 600 ° C. or higher, the adhesion of the alloyed galvanized steel sheet is remarkably improved. The reason is considered as follows. When the winding temperature of the steel sheet during hot rolling is set to 600 ° C. or higher, a grain boundary oxide layer is formed below the iron-based oxide layer generated during hot rolling. This grain boundary oxide layer is
Oxides are present in the form of oxides dispersed in the surface layer of the steel sheet. This grain boundary oxide layer significantly suppresses the alloying element such as Mn added as a component in the steel from being concentrated on the surface during the annealing or raising the temperature in the hot-dip galvanizing production process, and during the subsequent alloying treatment. It has the effect of improving the iron diffusion rate.
Therefore, for the above-mentioned reason, by defining the winding temperature at the time of hot rolling, the alloying speed is increased as a whole, and the effect of increasing the temperature increasing speed at the time of the alloying treatment is more effective.
【００１４】合金化時の昇温速度を３０℃／ｓｅｃ以上
にするための具体的手段としては、ガス加熱、インダク
ション・ヒーティングなどを挙げることができる。本発
明では、昇温速度を３０℃／ｓｅｃ以上に確保できれ
ば、その手段を特に限定するものではない。さらに、合
金化処理後に４２０℃までの冷却速度を３０℃／ｓｅｃ
以上確保するには、ガス冷却やミスト冷却又はフォグ冷
却等のように水を噴霧して冷却する等の手段が挙げられ
るが、前記した昇温速度を高める手段と同様に、本発明
では、その手段を特に限定するものではない。Specific means for increasing the temperature at the time of alloying to 30 ° C./sec or more include gas heating, induction heating, and the like. In the present invention, the means is not particularly limited as long as the heating rate can be maintained at 30 ° C./sec or more. Further, after the alloying treatment, the cooling rate up to 420 ° C. is increased by 30 ° C./sec.
In order to ensure the above, means such as spraying water and cooling such as gas cooling, mist cooling or fog cooling, etc., is mentioned. The means is not particularly limited.
【００１５】本発明は、熱間圧延時の巻取温度を規定す
ることにより実現するものであるが、熱間圧延後から溶
融めっきまでの工程としては特にこれを限定するもので
はなく、めっき素材としては冷間圧延鋼板、熱延鋼板の
いづれでもよい。[0015] The present invention is realized by defining the winding temperature during hot rolling, but the process from hot rolling to hot-dip coating is not particularly limited. Any of a cold-rolled steel sheet and a hot-rolled steel sheet may be used.
【００１６】[0016]
【実施例】以下本発明の実施例を挙げて説明する。Ｔｉ
−Ｎｂ系の極低炭素軟鋼板を実ラインで表１に示す各巻
き取り条件温度で製造した。この材料を、実験室規模で
酸洗、冷間圧延し、実験室で竪型溶融めっき装置を用
い、アルカリ電解脱脂、塩酸酸洗に引き続き、以下の条
件で焼鈍し、溶融亜鉛めっきを行った。 （焼鈍条件） 雰囲気 ： ５％Ｈ2 −Ｎ2 露点 ： −４０℃ 昇温速度 ： １０℃／ｓｅｃ 焼鈍温度 ： ８００℃ 冷却時間 ： ２０ｓｅｃ． 但し、焼鈍後の冷却は、雰囲気ガスを鋼板に吹き付ける
ことにより行った。また、鋼板に取り付けた熱電対によ
って鋼板の温度を測定し、最も冷却速度の遅くなるめっ
き浴浸入直前の冷却速度を検出してそれも表１に示し
た。 （溶融めっき条件） めっき浴濃度： Ａｌ：０．１４ｗｔ％、Ｆｅ：０．０４ｗｔ％、 Ｐｂ：０．００８ｗｔ％ 浴温 ： ４７５℃ 浸入板温 ： ４７５℃ 浸漬時間 ： １ｓｅｃ． めっき付着量： ５０ｇ／ｍ2 次に、以上の方法で製造した溶融亜鉛めっき鋼板を、直
接通電方式の加熱炉に装入し、一定温度で合金化処理を
行い、窒素ガスを吹き付けて冷却した。昇温速度の調整
は、投入電力を適宜変更することにより行い、冷却速度
の調整は窒素ガス流量を適宜変更することにより行っ
た。表１には、板温４２０℃以上での昇温速度、合金化
温度、合金化時間、さらに合金化処理後の板温が４２０
℃になるまでの冷却速度も記載してある。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Ti
-Nb-based ultra-low carbon mild steel sheets were produced on actual lines at each winding condition temperature shown in Table 1. This material was pickled and cold-rolled on a laboratory scale, and subjected to alkaline electrolytic degreasing and hydrochloric acid pickling, then annealed under the following conditions, and hot-dip galvanized using a vertical hot-dip coating apparatus in the laboratory. . (Annealing conditions) Atmosphere: 5% H 2 -N 2 Dew point: -40 ° C Heating rate: 10 ° C / sec Annealing temperature: 800 ° C Cooling time: 20 sec. However, cooling after annealing was performed by blowing an atmosphere gas onto the steel sheet. In addition, the temperature of the steel sheet was measured by a thermocouple attached to the steel sheet, and the cooling rate immediately before the infiltration of the plating bath, at which the cooling rate was the slowest, was detected. (Hot-dip plating conditions) Plating bath concentration: Al: 0.14 wt%, Fe: 0.04 wt%, Pb: 0.008 wt% Bath temperature: 475 ° C Penetration plate temperature: 475 ° C Immersion time: 1 sec. Coating weight: 50 g / m 2 Next, more galvanized steel sheet manufactured by the method, and charged into a heating furnace of direct energization method performs alloying at a constant temperature, and cooled by blowing nitrogen gas . Adjustment of the heating rate was performed by appropriately changing the input power, and adjustment of the cooling rate was performed by appropriately changing the flow rate of the nitrogen gas. Table 1 shows that the rate of temperature increase, the alloying temperature, the alloying time at a plate temperature of 420 ° C. or more, and the plate temperature after the alloying treatment were 420 ° C.
The cooling rate up to ° C. is also described.
【００１７】[0017]
【表１】 [Table 1]
【００１８】上記のようにして得られた合金化溶融亜鉛
めっき鋼板のめっき層を、インヒビター入りの塩酸に溶
解させ、ＩＣＰ発光分光分析法でめっき層中の鉄含有量
を分析した結果を表１に示す。さらに、めっき層の性能
試験としては、サンプル・サイズ：幅４０ｍｍ×長さ１
００ｍｍのサンプルを９０度曲げ戻した時のテープ剥離
しためっきを、めっき剥離量として螢光Ｘ線分析するパ
ウダリング性試験を行い、めっき剥離量として螢光Ｘ線
にて測定したｃｐｓ（ｃｏｕｎｔ／ｓｅｃ）を指標と
し、このｃｐｓ値も合わせて表１に示した。The plating layer of the alloyed hot-dip galvanized steel sheet obtained as described above was dissolved in hydrochloric acid containing an inhibitor, and the iron content in the plating layer was analyzed by ICP emission spectroscopy. Shown in Further, as a performance test of the plating layer, a sample size: width 40 mm × length 1
The plating stripped from the tape when the 00 mm sample was bent back by 90 degrees was subjected to a powdering test for X-ray fluorescence analysis as the amount of plating peeling, and the cps (count / sec) as an index, and this cps value is also shown in Table 1.
【００１９】[0019]
【発明の効果】表１に示すように、熱間圧延時の巻き取
り温度、焼鈍後の冷却速度、合金化処理時の昇温速度、
合金化温度、冷却速度、さらにめっき層中の鉄含有率を
それぞれ適正化することによって、合金化溶融亜鉛めっ
き鋼板のめっき密着性を飛躍的に向上させることができ
る。本発明によれば、従来に比し格段とめっき密着性に
優れた合金化溶融亜鉛めっき鋼板を製造することができ
るようになった。As shown in Table 1, the winding temperature during hot rolling, the cooling rate after annealing, the rate of temperature rise during alloying,
By optimizing the alloying temperature, the cooling rate, and the iron content in the plating layer, the plating adhesion of the galvannealed steel sheet can be significantly improved. ADVANTAGE OF THE INVENTION According to this invention, it has become possible to manufacture an alloyed hot-dip galvanized steel sheet that is much more excellent in plating adhesion than in the past.
Claims (2)
り、素材となる鋼板の熱間圧延時の巻取温度を６００℃
以上とし、溶融めっき後、３０℃／ｓｅｃ以上の昇温速
度で４７０〜５１０℃まで昇温しこの温度域に保持する
合金化処理を行い、鉄含有率８〜１１ｗｔ％のＺｎ−Ｆ
ｅ合金めっき層を得ることを特徴とするめっき密着性に
優れた合金化溶融亜鉛めっき鋼板の製造方法。In the production of an alloyed hot-dip galvanized steel sheet, the winding temperature during hot rolling of a steel sheet as a material is set to 600 ° C.
As described above, after hot-dip plating, an alloying process is performed to raise the temperature to 470 to 510 ° C. at a rate of 30 ° C./sec or higher and to maintain the temperature in this temperature range, so that Zn—F having an iron content of 8 to 11 wt% is obtained.
A method for producing an alloyed hot-dip galvanized steel sheet having excellent plating adhesion, characterized by obtaining an e-alloy plating layer.
０℃／ｓｅｃ以上の冷却速度で冷却することを特徴とす
る請求項１記載のめっき密着性に優れた合金化溶融亜鉛
めっき鋼板の製造方法。2. After the alloying treatment, the temperature is increased up to 420 ° C.
The method for producing a galvannealed steel sheet having excellent plating adhesion according to claim 1, wherein the steel sheet is cooled at a cooling rate of 0 ° C / sec or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07315297A JP3400289B2 (en) | 1997-03-26 | 1997-03-26 | Manufacturing method of galvannealed steel sheet with excellent plating adhesion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07315297A JP3400289B2 (en) | 1997-03-26 | 1997-03-26 | Manufacturing method of galvannealed steel sheet with excellent plating adhesion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10265925A true JPH10265925A (en) | 1998-10-06 |
| JP3400289B2 JP3400289B2 (en) | 2003-04-28 |
Family
ID=13509934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07315297A Expired - Fee Related JP3400289B2 (en) | 1997-03-26 | 1997-03-26 | Manufacturing method of galvannealed steel sheet with excellent plating adhesion |
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| Country | Link |
|---|---|
| JP (1) | JP3400289B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002088459A (en) * | 1999-11-08 | 2002-03-27 | Kawasaki Steel Corp | Galvanized steel sheet excellent in balance of strength- ductility and adhesion of plating and its production method |
| JP2007500285A (en) * | 2003-07-29 | 2007-01-11 | フェストアルピネ シュタール ゲーエムベーハー | Method for manufacturing hardened steel parts |
| WO2008044716A1 (en) | 2006-10-13 | 2008-04-17 | Nippon Steel Corporation | Apparatus and process for producing steel sheet plated by hot dipping with alloyed zinc |
-
1997
- 1997-03-26 JP JP07315297A patent/JP3400289B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002088459A (en) * | 1999-11-08 | 2002-03-27 | Kawasaki Steel Corp | Galvanized steel sheet excellent in balance of strength- ductility and adhesion of plating and its production method |
| JP4552310B2 (en) * | 1999-11-08 | 2010-09-29 | Ｊｆｅスチール株式会社 | Hot-dip galvanized steel sheet excellent in strength-ductility balance and plating adhesion and method for producing the same |
| JP2007500285A (en) * | 2003-07-29 | 2007-01-11 | フェストアルピネ シュタール ゲーエムベーハー | Method for manufacturing hardened steel parts |
| WO2008044716A1 (en) | 2006-10-13 | 2008-04-17 | Nippon Steel Corporation | Apparatus and process for producing steel sheet plated by hot dipping with alloyed zinc |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3400289B2 (en) | 2003-04-28 |
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