JP2707928B2 - Hot-dip galvanizing method for silicon-containing steel sheet - Google Patents
Hot-dip galvanizing method for silicon-containing steel sheetInfo
- Publication number
- JP2707928B2 JP2707928B2 JP4281329A JP28132992A JP2707928B2 JP 2707928 B2 JP2707928 B2 JP 2707928B2 JP 4281329 A JP4281329 A JP 4281329A JP 28132992 A JP28132992 A JP 28132992A JP 2707928 B2 JP2707928 B2 JP 2707928B2
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- Prior art keywords
- steel sheet
- hot
- plating
- steel
- silicon
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- Other Surface Treatments For Metallic Materials (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、低合金鋼板、特に珪素
含有鋼板に対して、不めっきを生じさせることなくめっ
きを施すことができる溶融亜鉛めっき方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot dip galvanizing method capable of plating low-alloy steel sheets, particularly silicon-containing steel sheets, without causing non-plating.
【０００２】[0002]
【従来の技術】近年、家電、建材、および自動車等の産
業分野においては溶融亜鉛めっき鋼板が大量に使用され
ているが、とりわけ経済性とその防錆機能および塗装後
の性能に優れる合金化溶融亜鉛めっき鋼板が広く用いら
れている。2. Description of the Related Art In recent years, galvanized steel sheets are used in large quantities in the industrial fields such as home appliances, building materials, and automobiles. Galvanized steel sheets are widely used.
【０００３】溶融亜鉛めっき鋼板は、通常、適当な脱脂
洗浄工程を経た後、もしくは脱脂洗浄を行うことなく、
鋼板を弱酸化性雰囲気中もしくは還元性雰囲気中で予熱
した後、水素＋窒素の還元性雰囲気中で焼鈍し、次い
で、めっきに適した温度まで冷却した後、溶融亜鉛に浸
漬することにより製造される。焼鈍の前工程の予熱時に
は鋼板表面に80nm程度の厚さの酸化膜が形成される方が
溶融亜鉛との濡れ性の点から望ましいとされており、そ
れ以上の厚さの酸化膜の形成はむしろドロスの発生を増
し、溶融めっきの密着性に悪影響を及ぼすと考えられて
いる。亜鉛浴は後述の合金化溶融亜鉛めっき鋼板の製造
の範囲も含めると0.08〜0.18重量％のAlを含むものが用
いられている。[0003] A hot-dip galvanized steel sheet is usually subjected to an appropriate degreasing and washing step or without performing degreasing and washing.
It is manufactured by preheating a steel sheet in a weakly oxidizing atmosphere or a reducing atmosphere, annealing in a reducing atmosphere of hydrogen and nitrogen, cooling to a temperature suitable for plating, and immersing it in molten zinc. You. It is considered desirable to form an oxide film with a thickness of about 80 nm on the steel sheet surface during preheating in the pre-annealing process from the viewpoint of wettability with molten zinc. Rather, it is thought that dross generation increases, which adversely affects the adhesion of hot-dip plating. As the zinc bath, a bath containing 0.08 to 0.18% by weight of Al is used, including the range of production of a galvannealed steel sheet described below.
【０００４】合金化溶融亜鉛めっき鋼板は、通常、前記
のようにして連続的に溶融亜鉛めっきを施した鋼板を熱
処理炉で 500〜600 ℃の材料温度に３〜30秒加熱し、亜
鉛層と鋼板素地との間でFeとZnの相互拡散を行わせ、め
っき層をFe−Zn合金とすることにより製造される。従っ
て、合金化溶融亜鉛めっき鋼板のめっき層はFe−Znの金
属間化合物からなり、一般にその平均Fe濃度は８〜12重
量％になるように調整されている。[0004] The alloyed hot-dip galvanized steel sheet is usually prepared by continuously heating a hot-dip galvanized steel sheet to a material temperature of 500 to 600 ° C for 3 to 30 seconds in a heat treatment furnace as described above. It is manufactured by causing Fe and Zn to interdiffuse with a steel sheet substrate and forming a plating layer of an Fe-Zn alloy. Accordingly, the plating layer of the alloyed hot-dip galvanized steel sheet is made of an intermetallic compound of Fe-Zn, and its average Fe concentration is generally adjusted to be 8 to 12% by weight.
【０００５】合金化溶融亜鉛めっき鋼板のめっき付着量
は片面当たり25〜70g/m2であり、25g/m2を下回るものは
通常の手段で製造することが難しく、70g/m2を上回るも
のはめっき層の耐パウダリング性を確保することが困難
であることから一般には供給されていない。また、めっ
き皮膜中には通常0.12〜0.2 重量％前後のAlが含有され
ていることが多い。これは合金化溶融亜鉛めっき鋼板と
同一設備で製造される溶融亜鉛めっき鋼板のめっき層と
鋼の界面における合金層の生成を抑制し、めっき皮膜の
加工性を保持するためにめっき浴に添加されるAlが不可
避的にめっき皮膜中に混入することもあるが、合金化溶
融亜鉛めっき皮膜の耐パウダリング性を確保し、かつ製
造時のドロスの発生を抑制するうえから、めっき浴中に
0.08〜0.11重量％程度のAlを混入させることがむしろ適
当であると考えられている。めっき浴中のAlはめっき層
中に富化する傾向があるため、0.08〜0.11重量％程度の
Alを含むめっき浴でめっきを行うと、めっき皮膜中のAl
濃度は0.12〜0.2 重量％の範囲となる。[0005] coating weight of the galvannealed steel sheet is per side 25~70g / m 2, well below the 25 g / m 2 is difficult to manufacture by conventional means, those greater than 70 g / m 2 Is generally not supplied because it is difficult to ensure the powdering resistance of the plating layer. In addition, the plating film often contains about 0.12 to 0.2% by weight of Al. This is added to the plating bath to suppress the formation of an alloy layer at the interface between the coating layer and the steel of the hot-dip galvanized steel sheet manufactured in the same equipment as the galvannealed steel sheet, and to maintain the workability of the coating film. Al may be inevitably mixed into the plating film.However, in order to ensure the powdering resistance of the galvannealed film and to suppress the dross during production,
It is considered rather appropriate to incorporate about 0.08 to 0.11% by weight of Al. Al in the plating bath tends to be enriched in the plating layer.
When plating is performed in a plating bath containing Al, Al in the plating film
The concentration ranges from 0.12 to 0.2% by weight.
【０００６】従来、溶融亜鉛めっき鋼板および合金化溶
融亜鉛めっき鋼板の母材には、主として低炭素Alキルド
鋼板、極低炭素Ti添加鋼板等が用いられていたが、近
年、自動車材料の高強度化が要求されることもあり、Si
を 0.2重量％以上含有する珪素含有鋼板が用いられよう
としている。Siは鋼の延性を損なわずに強度を向上させ
る利点があり、その意味では珪素添加鋼は自動車用の溶
融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板の母
材として有望である。Conventionally, low-carbon Al-killed steel sheets, ultra-low-carbon Ti-added steel sheets, and the like have been mainly used as base materials for hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets. May be required, Si
Steel containing 0.2% by weight or more is being used. Si has the advantage of improving the strength without impairing the ductility of the steel, and in that sense, silicon-added steel is promising as a base material for hot-dip galvanized steel sheets for automobiles and alloyed hot-dip galvanized steel sheets.
【０００７】しかしながら、珪素含有鋼板を母材とする
溶融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板は
以下に述べるように品質面および生産面で問題がある。However, hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets using silicon-containing steel sheets as base materials have problems in quality and production as described below.
【０００８】珪素含有鋼板を前述の通常のプロセスで溶
融亜鉛めっきすると、めっき前の焼鈍過程でその雰囲気
中の極微量の水分と鋼板中のSiが反応し、Si-Oxideを鋼
板表面に形成するため、鋼のSi含有量の増加に伴い溶融
亜鉛との濡れ性が急激に低下する。その結果、不めっき
が多発する。このような問題に対して、予め酸化性雰囲
気中で鋼板を加熱し、その表面に鉄の酸化物を形成させ
ることによって濡れ性が改善されることが知られてい
る。しかし、Si含有量が 0.2重量％を超える鋼板の場合
には、通常の溶融亜鉛めっきプロセスにおける酸化性雰
囲気、例えば、無酸化炉の空燃比を１〜1.35とする酸化
性雰囲気中での予熱では濡れ性が改善されるまでの十分
な酸化鉄が形成されないばかりか、めっき後に合金化処
理する場合の合金化処理速度が著しく遅く、生産能率が
大きく阻害されるという欠点がある。特に、鋼板の成形
性を向上させるためにTiを添加した極低炭素鋼をベース
としてこれにSi添加とした鋼板の場合、再結晶化のため
の焼鈍温度が 800℃以上と高温になるため、鋼板表面で
のSi-Oxideの析出が一層顕著になり、濡れ性の確保がさ
らに困難となる。When a silicon-containing steel sheet is hot-dip galvanized by the above-described normal process, a very small amount of moisture in the atmosphere reacts with Si in the steel sheet in an annealing process before the plating to form Si-Oxide on the steel sheet surface. Therefore, the wettability with molten zinc decreases rapidly with an increase in the Si content of the steel. As a result, non-plating frequently occurs. In order to solve such a problem, it is known that the wettability is improved by heating a steel sheet in an oxidizing atmosphere in advance and forming an oxide of iron on the surface of the steel sheet. However, in the case of a steel sheet having a Si content of more than 0.2% by weight, preheating in an oxidizing atmosphere in a normal hot-dip galvanizing process, for example, in an oxidizing atmosphere with an air-fuel ratio of 1 to 1.35 in a non-oxidizing furnace, Not only is iron oxide not sufficiently formed until the wettability is improved, but also the alloying treatment speed in the case of alloying treatment after plating is extremely slow, and the production efficiency is greatly impaired. In particular, in the case of a steel sheet with Si added to the base of ultra-low carbon steel with Ti added to improve the formability of the steel sheet, the annealing temperature for recrystallization is as high as 800 ° C or more, Precipitation of Si-Oxide on the steel sheet surface becomes more remarkable, and it becomes more difficult to secure wettability.
【０００９】溶融亜鉛との濡れ性を改善する別の方法と
して、溶融めっきに先立って鋼板の表面にNiの下地めっ
きを施す方法が知られている（例えば、特公昭61−9386
号公報）。しかし、この方法では、Si含有量が 0.2重量
％以上の鋼を対象とする場合、付着量が200mg/m2以上の
Niめっきを施すことが必要となるためコストの上昇を招
くほか、このような大量のNiめっきを施した場合には、
溶融亜鉛めっきの濡れ性は改善されるものの、合金化処
理過程でめっき表面にSi、Niに起因する欠陥が多発する
という問題が生じる。As another method for improving the wettability with hot-dip zinc, a method is known in which the surface of a steel sheet is pre-plated with Ni before hot-dip plating (for example, Japanese Patent Publication No. 61-9386).
No.). However, in this method, when steel containing 0.2% by weight or more of Si is targeted, the amount of adhesion is 200 mg / m 2 or more.
In addition to raising the cost because it is necessary to apply Ni plating, when such a large amount of Ni plating is applied,
Although the wettability of hot-dip galvanizing is improved, there arises a problem that defects caused by Si and Ni frequently occur on the plating surface during the alloying process.
【００１０】さらに、Niめっき以外にも、例えばFeめっ
き等を予め施してSi添加鋼の不めっきを防止することは
可能であるが、このためには１g/m2以上のFeめっきを施
す必要があり、極めて不経済である。[0010] In addition to Ni plating, for example, it is possible to preliminarily apply Fe plating or the like to prevent non-plating of Si-added steel, but for this purpose, it is necessary to apply Fe plating of 1 g / m 2 or more. And it is extremely uneconomical.
【００１１】このようなことから、自動車用高強度材料
として魅力のある珪素含有鋼板も、これを溶融亜鉛めっ
きないしは合金化処理する実際的な手段を欠いているの
が実情である。For these reasons, silicon-containing steel sheets that are attractive as high-strength materials for automobiles lack actual means for hot-dip galvanizing or alloying.
【００１２】[0012]
【発明が解決しようとする課題】本発明はこのような実
情に鑑みてなされたもので、低合金鋼板、特にSi含有量
が 0.2重量％以上の鋼板を母材として、不めっきを生じ
させることなくめっきすることができ、かつ、めっき後
の鋼板の合金化処理速度を低下させず、経済性の高い溶
融亜鉛めっき方法を提供することが本発明の課題であ
る。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to produce a non-plated steel sheet from a low alloy steel sheet, particularly a steel sheet having a Si content of 0.2% by weight or more. It is an object of the present invention to provide a hot-dip galvanizing method that can be plated without plating, does not lower the alloying treatment speed of the steel sheet after plating, and is highly economical.
【００１３】[0013]
【課題を解決するための手段】本発明者らは上記の課題
を解決するために検討を重ねた結果、(a) 母材鋼板（Si
含有鋼板）の表面に予め極微量の金属電気めっきを施す
工程、(b) めっき後の鋼板を弱酸化性雰囲気中で酸化す
る工程、および、(c) 酸化処理後の鋼板を 700℃以下の
温度で還元する工程、を組み入れることにより、溶融亜
鉛めっきならびにその後の合金化処理を円滑に行えるこ
とを見いだした。前記の電気めっきに用いる極微量の金
属としては、酸素親和力が母材を構成するFeと同等もし
くはFeよりも小さいものがよく、Fe、Cu、Ni、Coなどが
好適である。Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors found that (a) a base material steel plate (Si
(B) oxidizing the plated steel sheet in a weakly oxidizing atmosphere, and (c) subjecting the oxidized steel sheet to 700 ° C or lower. By incorporating the step of reducing at a temperature, it has been found that hot-dip galvanizing and subsequent alloying can be performed smoothly. As the trace amount of metal used for the electroplating, those having an oxygen affinity equal to or smaller than Fe constituting the base material are preferable, and Fe, Cu, Ni, Co, and the like are preferable.
【００１４】本発明は、上記の知見に基づいてなされた
もので、その要旨は、下記およびの溶融亜鉛めっき
方法にある。The present invention has been made based on the above findings, and its gist lies in the following hot-dip galvanizing methods.
【００１５】 Siを 0.2重量％以上含有する鋼板の表
面に予めNi、Fe、CuおよびCoの１種以上を５〜70mg/m2
の付着量で電気めっきし、次いで 700℃以下の酸化性雰
囲気中で加熱して鋼板表面にFeに換算して 0.3〜1.5g/m
2 の酸化鉄を形成させた後、 500〜650 ℃の温度域で還
元し、続いて溶融亜鉛めっきを施すことを特徴とする珪
素含有鋼板の溶融亜鉛めっき方法。On the surface of a steel sheet containing 0.2% by weight or more of Si, at least one of Ni, Fe, Cu and Co is preliminarily coated with 5-70 mg / m 2.
Electroplating with the adhesion amount of, then heated in an oxidizing atmosphere of 700 ° C or less, and converted to Fe on the steel sheet surface in the range of 0.3 to 1.5 g / m
2. A hot-dip galvanizing method for a silicon-containing steel sheet, comprising forming iron oxide of 2 , reducing in a temperature range of 500 to 650 ° C., and subsequently performing hot-dip galvanizing.
【００１６】 前記の溶融亜鉛めっきに続いて、合
金化処理することを特徴とする珪素含有鋼板の溶融亜鉛
めっき方法。[0016] A hot dip galvanizing method for a silicon-containing steel sheet, characterized by performing an alloying treatment after the hot dip galvanizing.
【００１７】[0017]
【作用】以下に、本発明方法を工程順に詳細に説明す
る。The method of the present invention will be described below in the order of steps.
【００１８】先ず、本発明で対象とする鋼板は、Siを
0.2重量％以上含有する鋼板である。First, the steel sheet targeted in the present invention is made of Si
Steel sheet containing 0.2% by weight or more.
【００１９】これは、Si含有量が 0.2重量％未満の鋼板
の場合は従来技術の範囲内で対応が可能なためである。This is because a steel sheet having a Si content of less than 0.2% by weight can be dealt with within the range of the prior art.
【００２０】この鋼板は焼鈍を行った冷延鋼板（但し、
冷間圧延ままでフルハード材の場合を除く）もしくは酸
洗後の熱延鋼板である。すなわち、本発明方法では、従
来、連続溶融亜鉛めっき設備（ＣＧＬ）を用いて一連の
工程の中で行っていた鋼板の焼鈍もしくは熱処理による
材質調整を行わず、予め所定の材料特性に調質された鋼
板を母材として用いる。これは、焼鈍と溶融めっきとを
分離し、焼鈍過程で表面に濃化したSiの酸化物が直接溶
融亜鉛と接触するのを避けようという観点から採られる
条件である。従って、対象が冷延鋼板であれば所定の特
性が得られるように、あらかじめバッチ式または連続式
焼鈍炉で焼鈍する。但し、冷延鋼板であっても、冷間圧
延を行ったままでフルハード材である場合は焼鈍の必要
はない。This steel sheet is an annealed cold-rolled steel sheet (however,
It is a hot-rolled steel sheet after cold-rolling, except for a full-hard material) or after pickling. That is, in the method of the present invention, the steel sheet is tempered to a predetermined material characteristic in advance without performing the material adjustment by annealing or heat treatment of the steel sheet, which is conventionally performed in a series of steps using the continuous hot-dip galvanizing equipment (CGL). Used steel plate as a base material. This is a condition adopted from the viewpoint of separating the annealing from the hot-dip plating and avoiding that the oxide of Si concentrated on the surface during the annealing process comes into direct contact with the molten zinc. Therefore, if the target is a cold-rolled steel sheet, it is previously annealed in a batch or continuous annealing furnace so as to obtain predetermined characteristics. However, even in the case of a cold-rolled steel sheet, annealing is not necessary in the case of a fully hardened material as it is after cold rolling.
【００２１】また、熱延鋼板を対象とする場合は酸洗処
理を行ったものであればよい。When a hot-rolled steel sheet is to be used, any steel sheet which has been subjected to pickling treatment may be used.
【００２２】上記のSi含有鋼板をめっき母材として本発
明の最初の工程である電気めっきを行うのであるが、そ
の前処理として通常の脱脂および酸洗を行うことが望ま
しい。熱延鋼板を対象とする場合は既に酸洗処理を行っ
ているので、原則的にはその必要はないが、製板後の貯
蔵期間が長い場合等、必要に応じて再度酸洗すればよ
い。また、焼鈍を連続式焼鈍炉で行う場合、焼鈍炉の出
側に酸洗設備を備えたものもあるので、このような設備
で焼鈍された鋼板に対しては脱脂、酸洗の工程は不要で
ある。The electroplating, which is the first step of the present invention, is carried out using the above-mentioned Si-containing steel sheet as a plating base material, and it is desirable to carry out ordinary degreasing and pickling as a pretreatment. In the case of hot-rolled steel sheets, pickling has already been performed, so in principle there is no need to do so, but if the storage period after plate making is long, pickling may be performed again if necessary. . In addition, when annealing is performed in a continuous annealing furnace, there is a type equipped with pickling equipment on the outlet side of the annealing furnace, so the steel plate annealed in such equipment does not require degreasing and pickling processes. It is.
【００２３】酸洗には、塩酸、弗酸、硫酸、硝酸等の希
釈液が用いられる。酸洗は、熱延鋼板の場合は熱延工程
で、また、予め焼鈍された冷延鋼板にあっては焼鈍工程
で鋼板の表面に生成したSi系の酸化膜を幾分溶解する効
果はあるが、Ti等の酸化物を鋼板の表面に濃化させる等
の悪影響もある。従って、過度の酸洗はひかえることが
望ましい。酸洗の好ましい条件は、３〜15％の塩酸を用
い、液温：40〜95℃、酸洗時間：２〜20秒である。For pickling, a diluent such as hydrochloric acid, hydrofluoric acid, sulfuric acid or nitric acid is used. Pickling has the effect of dissolving somewhat the Si-based oxide film generated on the surface of the steel sheet in the hot rolling process in the case of a hot-rolled steel sheet and in the case of a cold-rolled steel sheet that has been annealed in advance. However, there are also adverse effects such as the concentration of oxides such as Ti on the surface of the steel sheet. Therefore, it is desirable to avoid excessive pickling. The preferred conditions for pickling are using 3 to 15% hydrochloric acid, a liquid temperature of 40 to 95 ° C., and a pickling time of 2 to 20 seconds.
【００２４】酸洗後の鋼板の表面に、Fe、Cu、Niおよび
Coの少なくとも１種を電気めっきする。少なくとも１種
というのは、これら金属の単層めっきであってもよく、
例えばFeめっきをした後にその上にNiめっきを施しても
よい。あるいは、Fe−Ni合金めっきをしてもよい、とい
うことである。On the surface of the steel plate after pickling, Fe, Cu, Ni and
Electroplate at least one of Co. At least one kind may be a single layer plating of these metals,
For example, after performing Fe plating, Ni plating may be performed thereon. Alternatively, it is possible to perform Fe-Ni alloy plating.
【００２５】めっき付着量は、 5mg/m2 未満では溶融亜
鉛との濡れ性の改善が不十分で不めっきが発生しやす
く、一方、 70mg/m2を超えるとその効果が飽和し不経済
となるので、 5〜70mg/m2 とする。このような微量の金
属めっきが何故に溶融めっき性の改善に効果があるのか
不明であるが、この金属めっきを施した後は、７００℃
を超える高温での熱処理を行わないので、これらの金属
が母材中に拡散することなく鋼板表面に部分的に残留
し、鋼板が溶融亜鉛に接触した時、亜鉛が母材に付着す
る反応の活性点として機能するものと推察される。When the coating weight is less than 5 mg / m 2 , the improvement of the wettability with the molten zinc is insufficient and non-plating is liable to occur. On the other hand, when the coating weight exceeds 70 mg / m 2 , the effect is saturated and uneconomical. Therefore, the concentration is 5 to 70 mg / m 2 . It is not clear why such a small amount of metal plating is effective in improving the hot-dip plating property, but after applying this metal plating, it is 700 ° C.
Does not perform heat treatment at a high temperature exceeding, these metals partially remaining on the steel sheet surface without diffusing into the base material, when the steel sheet is in contact with the molten zinc, zinc adheres to the base metal reaction It is presumed that it functions as the active point of.
【００２６】次いで、上記の電気めっきを施した鋼板を
酸化性雰囲気中で加熱して、鋼板の表面に酸化鉄を形成
させる。加熱温度は、 700℃を超えると鋼中のSiが鋼板
表面へ拡散して不めっきが発生しやすくなるほか、酸化
膜が剥離しやすくなり、この剥離した酸化膜は炉内ロー
ルに付着して鋼板に表面欠陥を生じさせるので、 700℃
以下、好ましくは 400〜650 ℃とする。下限は特に定め
ないが 300℃以下では酸化速度が小さく適当ではない。
また、加熱時の酸化性雰囲気としては、二酸化炭素、酸
素、水などの酸化性ガスを含む雰囲気を用いればよい。Next, the electroplated steel sheet is heated in an oxidizing atmosphere to form iron oxide on the surface of the steel sheet. If the heating temperature exceeds 700 ° C, Si in the steel diffuses to the steel sheet surface, causing non-plating to occur easily and the oxide film to peel easily, and the peeled oxide film adheres to the roll in the furnace. 700 ℃ as it causes surface defects on steel plate
Hereinafter, the temperature is preferably set to 400 to 650 ° C. The lower limit is not particularly defined, but at 300 ° C or lower, the oxidation rate is too low to be appropriate.
As an oxidizing atmosphere at the time of heating, an atmosphere containing an oxidizing gas such as carbon dioxide, oxygen, or water may be used.
【００２７】鋼板の表面に形成させる酸化鉄量は、Feに
換算して 0.3g/m2未満では不めっきが生じやすく、 1.5
g/m2を超えると次工程での酸化鉄の還元が不十分とな
り、やはり不めっきが発生しやすくなるので、Feに換算
して 0.3〜1.5g/m2 となるようにする。When the amount of iron oxide formed on the surface of the steel sheet is less than 0.3 g / m 2 in terms of Fe, non-plating is liable to occur.
If it exceeds g / m 2 , the reduction of iron oxide in the next step will be insufficient, and non-plating will also easily occur. Therefore, it is adjusted to 0.3 to 1.5 g / m 2 in terms of Fe.
【００２８】鋼板表面に酸化鉄を形成させた後、 500〜
650 ℃の温度域で還元する。この目的のためには、水素
５ vol％以上を含み残部が非酸化性ガスからなる雰囲気
がよく、例えば、水素と窒素からなり、露点が−15℃以
下の雰囲気とすればよい。この場合、温度が 500℃未満
では還元力が弱く酸化鉄の還元が不十分であり、 650℃
を超えると鋼中のSiの拡散が生じやすく、鋼板表面にSi
が濃化し、不めっきが発生しやすくなる。処理時間は15
〜20秒が適当である。After forming iron oxide on the steel sheet surface,
It is reduced in the temperature range of 650 ° C. For this purpose, an atmosphere containing 5 vol% or more of hydrogen and a balance of a non-oxidizing gas may be used. For example, an atmosphere containing hydrogen and nitrogen and having a dew point of −15 ° C. or less may be used. In this case, if the temperature is less than 500 ° C, the reducing power is weak and the reduction of iron oxide is insufficient,
If Si exceeds 300, the diffusion of Si in the steel tends to occur,
Is concentrated and non-plating is likely to occur. Processing time is 15
~ 20 seconds is appropriate.
【００２９】還元処理後の鋼板を 380〜550 ℃程度に冷
却し、Alを0.05〜0.15％程度含有する亜鉛浴中で溶融め
っきを施す。また、必要に応じてさらに合金化処理炉で
450〜600 ℃で１〜120 秒加熱する合金化処理を行う。The steel sheet after the reduction treatment is cooled to about 380 to 550 ° C., and hot-dip galvanized in a zinc bath containing about 0.05 to 0.15% of Al. Also, if necessary, use an alloying treatment furnace.
Perform alloying treatment by heating at 450 to 600 ° C for 1 to 120 seconds.
【００３０】上記本発明の溶融亜鉛めっき方法により、
珪素含有鋼板を母材として、不めっきのない表面特性の
優れた溶融亜鉛めっき鋼板ないしは合金化溶融亜鉛めっ
き鋼板を得ることができる。この方法によれば、Si含有
量が 1.5重量％を超える鋼板であっても溶融亜鉛めっき
が可能となる。According to the hot-dip galvanizing method of the present invention,
Using a silicon-containing steel sheet as a base material, a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet having excellent surface properties without non-plating can be obtained. According to this method, hot-dip galvanizing is possible even for a steel sheet having a Si content exceeding 1.5% by weight.
【００３１】[0031]
【実施例】表１に示す化学組成を有する高Si鋼の熱延鋼
板 (鋼種Ａ、板厚2.3mm 、未酸洗材）及び冷延鋼板 (鋼
種Ｂ〜Ｄ、板厚0.80mm、未焼鈍材) を 250mm×100mm に
裁断して供試材とし、Ｂ〜Ｄについては、水素15 vol％
で残部が窒素からなる露点−30℃の雰囲気中で、予め、
昇温速度15℃／秒、 850℃× 120秒の焼鈍を行った。EXAMPLES Hot-rolled steel sheets of high Si steel having the chemical composition shown in Table 1 (steel type A, sheet thickness 2.3 mm, non-acid-washed material) and cold-rolled steel sheets (steel types BD, sheet thickness 0.80 mm, unannealed) Material) is cut into 250 mm x 100 mm to obtain test materials. For B to D, 15 vol% hydrogen
In an atmosphere with a dew point of −30 ° C. consisting of nitrogen in advance,
Annealing was performed at a heating rate of 15 ° C./sec and 850 ° C. × 120 sec.
【００３２】これらの鋼板を80℃の５％ＨCl水溶液中で
５秒間酸洗し（一部の鋼板については酸洗を実施せ
ず）、その後、鋼板表面に、表２に示す条件で、２〜70
mg/m2 のNiめっき、２〜70mg/m2 のFeめっき、５mg/m2
のCuめっき、または10〜15mg/m2のCoめっきを施した
後、竪型溶融めっき装置を用いて酸化（予熱）処理、還
元処理および溶融亜鉛めっきを行った。この装置によれ
ば、供試材を所定の雰囲気で熱処理することができ、か
つ、還元雰囲気から直接溶融めっき浴中に浸漬すること
ができる。酸化処理は表３のａ〜ｅに示した条件で行い
（但し、ａは酸化処理せず）、還元処理はN2＋25 vol％
H2の雰囲気中で 600℃×60秒の条件で行い、還元処理
後、鋼板を 460℃に冷却して溶融亜鉛めっきを行った。
めっき浴の全Al濃度は 0.112％、全Fe濃度は 0.020％
で、めっき時間は１秒とし、ガスワイパーによりZn付着
量を約50g/m2 (片面当たり) に調整した。なお、不めっ
きを生じなかったものについては、さらに 500℃で合金
化処理を行った。These steel sheets were pickled in a 5% HCl aqueous solution at 80 ° C. for 5 seconds (no pickling was performed for some of the steel sheets). ~ 70
Ni plating mg / m 2, Fe plating 2~70mg / m 2, 5mg / m 2
After performing Cu plating or Co plating at 10 to 15 mg / m 2 , oxidation (preheating) treatment, reduction treatment, and hot dip galvanization were performed using a vertical hot-dip coating apparatus. According to this apparatus, the test material can be heat-treated in a predetermined atmosphere, and can be immersed directly in a hot-dip plating bath from a reducing atmosphere. The oxidation treatment was performed under the conditions shown in Tables a to e (where a was not oxidized), and the reduction treatment was N 2 +25 vol%.
The reduction was performed in an atmosphere of H 2 at 600 ° C. for 60 seconds. After the reduction treatment, the steel sheet was cooled to 460 ° C. and hot-dip galvanized.
Total Al concentration of plating bath is 0.112%, total Fe concentration is 0.020%
The plating time was 1 second, and the amount of Zn deposited was adjusted to about 50 g / m 2 (per side) with a gas wiper. In addition, alloying treatment was performed at 500 ° C. for those which did not generate non-plating.
【００３３】溶融亜鉛めっき後、不めっきの発生状況を
調査した。また、不めっきのなかったものについては合
金化処理を行い、合金化所要時間を測定した。After hot-dip galvanizing, the occurrence of non-plating was investigated. In addition, alloying treatment was carried out for those having no non-plating, and the required alloying time was measured.
【００３４】調査結果を表４に示す。なお、同表には、
電気めっきの前処理としての酸洗の有無、電気めっきの
目付量、酸化（予熱）方法、酸化鉄量および還元条件も
併せて示した。Table 4 shows the results of the investigation. In the table,
The presence / absence of pickling as a pretreatment for electroplating, the basis weight of electroplating, the oxidation (preheating) method, the amount of iron oxide, and the reducing conditions are also shown.
【００３５】表２の結果から明らかなように、本発明で
規定する条件で電気めっき、酸化（予熱）処理および還
元処理を行った場合は、不めっきを生じさせることなく
溶融亜鉛めっきを行うことができた。また、合金化も容
易であった。As is evident from the results in Table 2, when electroplating, oxidation (preheating) treatment and reduction treatment are performed under the conditions specified in the present invention, hot-dip galvanizing is performed without causing non-plating. Was completed. Alloying was also easy.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 [Table 2]
【００３８】[0038]
【表３】 [Table 3]
【００３９】[0039]
【表４（１）】 [Table 4 (1)]
【００４０】[0040]
【表４（２）】 [Table 4 (2)]
【００４１】[0041]
【発明の効果】以上説明したように、Siを含有する鋼板
に対して本発明方法を適用すれば、不めっきのない、表
面品質に優れた溶融亜鉛めっき鋼板および合金化溶融亜
鉛めっき鋼板を製造することができる。As described above, when the method of the present invention is applied to a steel sheet containing Si, a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet having no plating and excellent surface quality can be manufactured. can do.
【００４２】[0042]
Claims (2)
予めNi、Fe、CuおよびCoの１種以上を５〜70mg/m2 の付
着量で電気めっきし、次いで 700℃以下の酸化性雰囲気
中で加熱して鋼板表面にFeに換算して 0.3〜1.5g/m2 の
酸化鉄を形成させた後、 500〜650 ℃の温度域で還元
し、続いて溶融亜鉛めっきを施すことを特徴とする珪素
含有鋼板の溶融亜鉛めっき方法。1. A steel sheet containing 0.2% by weight or more of Si is electroplated in advance with at least one of Ni, Fe, Cu and Co at an adhesion amount of 5 to 70 mg / m 2 , and then oxidized at 700 ° C. or less. after forming the iron oxide 0.3 to 1.5 g / m 2 in terms of Fe on the surface of the steel sheet is heated in sexual atmosphere, it was reduced in a temperature range of 500 to 650 ° C., followed by applying a galvanizing A hot-dip galvanizing method for a silicon-containing steel sheet.
予めNi、Fe、CuおよびCoの１種以上を５〜70mg/m2 の付
着量で電気めっきし、次いで 700℃以下の酸化性雰囲気
中で加熱して鋼板表面にFeに換算して 0.3〜1.5g/m2 の
酸化鉄を形成させた後、 500〜650 ℃の温度域で還元
し、続いて溶融亜鉛めっきを施した後、合金化処理する
ことを特徴とする珪素含有鋼板の溶融亜鉛めっき方法。2. A steel sheet containing 0.2% by weight or more of Si is electroplated in advance with one or more of Ni, Fe, Cu and Co at an adhesion amount of 5 to 70 mg / m 2 , and then oxidized at 700 ° C. or less. after forming the iron oxide 0.3 to 1.5 g / m 2 in terms of Fe on the surface of the steel sheet is heated in sexual atmosphere, it was reduced in a temperature range of 500 to 650 ° C., subjected to subsequently galvanized And a galvanizing method for a silicon-containing steel sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4281329A JP2707928B2 (en) | 1992-10-20 | 1992-10-20 | Hot-dip galvanizing method for silicon-containing steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4281329A JP2707928B2 (en) | 1992-10-20 | 1992-10-20 | Hot-dip galvanizing method for silicon-containing steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06128758A JPH06128758A (en) | 1994-05-10 |
| JP2707928B2 true JP2707928B2 (en) | 1998-02-04 |
Family
ID=17637590
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4281329A Expired - Fee Related JP2707928B2 (en) | 1992-10-20 | 1992-10-20 | Hot-dip galvanizing method for silicon-containing steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2707928B2 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1112712A (en) * | 1997-04-28 | 1999-01-19 | Nippon Steel Corp | Manufacture of high tensile strength galvannealed steel sheet |
| JPH11199999A (en) * | 1998-01-16 | 1999-07-27 | Nippon Steel Corp | Production of high tensile strength hot dip galvanized steel plate |
| KR100902216B1 (en) * | 2002-09-12 | 2009-06-11 | 주식회사 포스코 | Method of manufacturing a hot dip galvanizing steel sheet containing Si |
| BRPI0608357A2 (en) | 2005-04-20 | 2010-01-05 | Nippon Steel Corp | hot dip galvanized annealed high strength steel sheet production method |
| JP4882446B2 (en) * | 2006-03-28 | 2012-02-22 | Ｊｆｅスチール株式会社 | Hot-dip galvanized steel sheet and method for producing galvannealed steel sheet |
| JP4882447B2 (en) * | 2006-03-28 | 2012-02-22 | Ｊｆｅスチール株式会社 | Method for producing hot-dip galvanized steel sheet |
| JP4804996B2 (en) | 2006-04-07 | 2011-11-02 | 新日本製鐵株式会社 | Method for producing alloyed hot-dip galvanized steel sheet with good workability, powdering property and slidability |
| CN101730752B (en) * | 2007-05-02 | 2013-05-01 | 塔塔钢铁艾默伊登有限责任公司 | Method for hot dip galvanising of AHSS or UHSS strip material, and such material |
| ES2876258T3 (en) | 2009-12-29 | 2021-11-12 | Posco | Zinc Plated Hot Pressed Parts and Production Procedure |
| KR20130076589A (en) | 2011-12-28 | 2013-07-08 | 주식회사 포스코 | High strength galvanized steel sheet having excellent surface property and coating adhesion method for manufacturing the same |
| CN108796568B (en) * | 2017-05-02 | 2020-07-14 | 贵州理工学院 | Method and device for preparing high-silicon steel thin strip under low-intensity magnetic field |
| US20230374639A1 (en) * | 2020-11-06 | 2023-11-23 | Jfe Steel Corporation | Galvanized steel sheet, electrodeposition-coated steel sheet, automotive part, method of producing electrodeposition-coated steel sheet, and method of producing galvanized steel sheet |
| EP4242357A4 (en) * | 2020-11-06 | 2024-05-22 | Jfe Steel Corp | Fe-electroplated steel sheet, electrodeposition coated steel sheet, automobile component, method for manufacturing electrodeposition coated steel sheet, and method for manufacturing fe-electroplated steel sheet |
| CN116457481A (en) * | 2020-11-06 | 2023-07-18 | 杰富意钢铁株式会社 | Alloyed galvanized steel sheet, electrodeposition-coated steel sheet, automobile part, method for producing electrodeposition-coated steel sheet, and method for producing alloyed galvanized steel sheet |
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| JPS55122865A (en) * | 1979-03-12 | 1980-09-20 | Nippon Steel Corp | Molten zinc plating method for difficult plating steel sheet |
| JPS6056418B2 (en) * | 1980-10-21 | 1985-12-10 | 新日本製鐵株式会社 | Manufacturing method of hot-dip galvanized steel sheet |
| JPS5776176A (en) * | 1980-10-28 | 1982-05-13 | Nippon Steel Corp | Manufacture of high preformance hot-galvanized steel plate |
| JPS6428351A (en) * | 1987-07-23 | 1989-01-30 | Nisshin Steel Co Ltd | Method for hot dip aluminizing hardly aluminizable steel sheet |
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