JP2001026852A - Production of galvanized steel sheet and galvannealed steel sheet - Google Patents
Production of galvanized steel sheet and galvannealed steel sheetInfo
- Publication number
- JP2001026852A JP2001026852A JP11201548A JP20154899A JP2001026852A JP 2001026852 A JP2001026852 A JP 2001026852A JP 11201548 A JP11201548 A JP 11201548A JP 20154899 A JP20154899 A JP 20154899A JP 2001026852 A JP2001026852 A JP 2001026852A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- zone
- hot
- heating zone
- galvanized steel
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、溶融亜鉛めっき鋼
板の製造方法に係わる。より詳細には、鋼板中にSi、P
の少なくとも一方を含み、引張強度が35kg/mm2以上の、
プレス成形性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の製造方法に係わる。[0001] The present invention relates to a method for producing a hot-dip galvanized steel sheet. More specifically, Si, P
Including at least one of the tensile strength of 35 kg / mm 2 or more,
The present invention relates to a method for producing a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet having excellent press formability.
【０００２】[0002]
【従来の技術】従来、自動車の燃費向上と排気ガス低減
の必要性から、自動車車体の軽量化が要求されてきた。
一方、自動車の安全性に対するニーズも高まっているこ
とから。車体を軽量化しつつ、高い車体強度を維持する
ことが望まれている。また、車体の部品には高度な耐食
性が要求される場合が多い。以上の背景から、自動車部
品の素材として、高強度溶融亜鉛めっき鋼板の使用が増
加しつつある。2. Description of the Related Art Conventionally, the need to improve vehicle fuel efficiency and reduce exhaust gas has required a reduction in the weight of an automobile body.
On the other hand, there is a growing need for vehicle safety. It is desired to maintain a high body strength while reducing the weight of the body. In addition, high corrosion resistance is often required for vehicle body components. From the above background, the use of high-strength hot-dip galvanized steel sheets as materials for automotive parts is increasing.
【０００３】他方、自動車用部品は形状が複雑なものが
多く、また、製造に際して高い生産性が要求されること
から、プレス成形により加工される場合が多い。しか
し、高強度鋼板は軟質鋼板と比べて延性や伸びフランジ
性が低いため、プレス成形性に劣るという問題がある。
そこで従来より、高強度と高延性あるいは高伸びフラン
ジ性を兼ね備えた、プレス成形性に優れる高強度溶融亜
鉛めっき鋼板の開発が要望されてきた。[0003] On the other hand, automotive parts often have complicated shapes and high productivity is required in manufacturing, so that they are often processed by press molding. However, high-strength steel sheets have lower ductility and stretch flangeability than soft steel sheets, and therefore have a problem of inferior press formability.
Therefore, there has been a demand for a high-strength hot-dip galvanized steel sheet having both high strength and high ductility or high stretch flangeability and excellent in press formability.
【０００４】溶融めっきを施さない冷延鋼板の場合は、
このような要望を満たす鋼板として、フェライト相とマ
ルテンサイト相からなる複合組織鋼板や残留オーステナ
イト相を含む鋼板が発明されてきた。[0004] In the case of a cold-rolled steel sheet not subjected to hot-dip plating,
As a steel sheet satisfying such demands, a steel sheet having a composite structure composed of a ferrite phase and a martensite phase and a steel sheet containing a retained austenite phase have been invented.
【０００５】しかし、一般的にこれらの鋼板は比較的多
量のSiやPを含有するため、これらの鋼板を用いて溶融
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
することは困難である。その理由は、鋼板を焼鈍する際
に鋼板表面でSiおよびPの選択酸化が起こり、溶融亜鉛
の濡れ性と、亜鉛と下地鋼板との反応性を低下させ、不
めっきが発生したり、合金化溶融亜鉛めっき鋼板を製造
するにあたって、被膜の合金化反応が著しく抑制される
ためである。However, since these steel sheets generally contain relatively large amounts of Si and P, it is difficult to produce hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets using these steel sheets. The reason is that during the annealing of the steel sheet, the selective oxidation of Si and P occurs on the steel sheet surface, lowering the wettability of the molten zinc and the reactivity between zinc and the base steel sheet, causing non-plating and alloying. This is because, when producing a hot-dip galvanized steel sheet, the alloying reaction of the coating is significantly suppressed.
【０００６】不めっきの発生は、製品の品質を著しく低
下させるため、実用上重大な問題となる。また、合金化
反応性の低下によって、合金化処理を行うために高温長
時間の熱処理が必要となるため、鋼板の材質に影響を与
えると共に、合金化処理設備の増大を招き、生産性を悪
化させる。[0006] The occurrence of non-plating is a serious problem in practical use since the quality of the product is significantly reduced. In addition, a decrease in alloying reactivity requires high-temperature and long-time heat treatment to perform the alloying treatment, which affects the material of the steel sheet and increases the number of alloying treatment facilities, thereby deteriorating productivity. Let it.
【０００７】従来、これらの問題を解決するために、連
続式溶融亜鉛めっきライン内の予熱帯および加熱帯にお
いて、一旦、鋼板表面にFe酸化物を形成させた後還元帯
において還元し、その後、めっきを施す方法が提案され
てきた。特許第2587724号公報および特許第2587725号公
報には、加熱帯において、火炎バーナーによって鋼板表
面に急速に酸化膜を生成させ、その後、還元炉におい
て、水素雰囲気中で酸化膜を還元する方法が開示されて
いる。また、特許第2792434号公報には、予熱帯および
加熱帯において、雰囲気の露点と鋼板温度を制御するこ
とにより、鋼板表面に酸化膜を形成し、その後還元炉に
おいて還元する方法が開示されている。Conventionally, in order to solve these problems, in a pre-tropical zone and a heating zone in a continuous hot-dip galvanizing line, an Fe oxide is once formed on the surface of a steel sheet and then reduced in a reduction zone. Methods for plating have been proposed. Japanese Patent No. 2587724 and Japanese Patent No. 2587725 disclose a method of rapidly generating an oxide film on a steel sheet surface by a flame burner in a heating zone, and then reducing the oxide film in a hydrogen atmosphere in a reduction furnace. Have been. Further, Japanese Patent No. 2792434 discloses a method of forming an oxide film on the steel sheet surface by controlling the dew point of the atmosphere and the steel sheet temperature in the pre-tropical zone and the heating zone, and thereafter reducing the steel sheet in a reduction furnace. .
【０００８】しかし、実際の連続式溶融亜鉛めっきライ
ンにこれらの方法を適用しようとすると、ライン内での
ピックアップの問題が発生する。すなわち、鋼板が表面
に酸化物を生成させた状態でロールに接触するため、ロ
ールに酸化物が付着する。その付着物が蓄積し、設備内
部を汚したり、後に続く鋼板に押し込まれ、押し疵等の
原因になる。However, when these methods are applied to an actual continuous hot-dip galvanizing line, a problem of pickup in the line occurs. That is, since the steel sheet comes into contact with the roll in a state where the oxide is generated on the surface, the oxide adheres to the roll. The deposits accumulate and stain the inside of the equipment or are pushed into the subsequent steel plate, causing a pressing flaw or the like.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、上記の事情
を鑑みてなされたものである。すなわち、SiおよびPを
含有する鋼板を下地とし、めっきの濡れ性と合金化処理
性に優れた溶融亜鉛めっき鋼板および合金化溶融亜鉛め
っき鋼板の製造方法を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a hot-dip galvanized steel sheet and a method for producing an alloyed hot-dip galvanized steel sheet that are based on a steel sheet containing Si and P and have excellent plating wettability and alloying processability.
【００１０】[0010]
【課題を解決するための手段】本発明者らは、上記の問
題を解決するために、連続式溶融亜鉛めっきラインにお
ける製造方法について検討を重ね、本発明を完成した。Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied a manufacturing method in a continuous hot-dip galvanizing line and completed the present invention.
【００１１】前記課題を解決するための本発明の手段は
次のとおりである。 (1)第１発明は、重量％で、Siを0.1％以上、Pを0.01％
以上のうちの少なくとも一種を含む鋼板を、予熱帯、加
熱帯、ラジアントチューブ方式の還元帯、冷却帯を備え
る熱処理炉で熱処理し、その後めっき浴に浸漬して亜鉛
めっきを施す溶融亜鉛めっき鋼板の製造方法において、
前記加熱帯を２つ以上の区域に分け、鋼板温度が500℃
未満である区域での空燃比を1.00以上1.3以下、鋼板温
度が570℃以上になる区域での空燃比を0.80以上1.1以下
とすることを特徴とする、溶融亜鉛めっき鋼板の製造方
法である。The means of the present invention for solving the above-mentioned problems are as follows. (1) In the first invention, Si is 0.1% or more and P is 0.01% by weight%.
A steel sheet containing at least one of the above is subjected to heat treatment in a heat treatment furnace equipped with a pre-tropical zone, a heating zone, a radiant tube type reduction zone, and a cooling zone, and then immersed in a plating bath to perform galvanization. In the manufacturing method,
Divide the heating zone into two or more zones, steel plate temperature 500 ℃
A method for producing a hot-dip galvanized steel sheet, characterized in that the air-fuel ratio in an area where the temperature is less than 1.00 is 1.3 or less and the air-fuel ratio in the area where the steel sheet temperature is 570 ° C. or more is 0.80 or more and 1.1 or less.
【００１２】(2)第２発明は、加熱帯において、鋼板を
加熱する手段として直火還元加熱方式を用いることを特
徴とする、第１発明に記載の溶融亜鉛めっき鋼板の製造
方法である。(2) The second invention is the method for producing a hot-dip galvanized steel sheet according to the first invention, characterized in that an open flame reduction heating system is used as a means for heating the steel sheet in the heating zone.
【００１３】(3)第３発明は、加熱帯において、鋼板温
度が400℃以上650℃以下である間に、鋼板とロールが連
続して接触する時間が0.5sec未満であることを特徴とす
る、第１発明、第２発明に記載の溶融亜鉛めっき鋼板の
製造方法である。(3) The third invention is characterized in that, in the heating zone, a continuous contact time between the steel sheet and the roll is less than 0.5 sec while the steel sheet temperature is 400 ° C. or more and 650 ° C. or less. , A method for manufacturing a hot-dip galvanized steel sheet according to the first and second inventions.
【００１４】(4)第４発明は、第１発明〜第３発明の製
造方法によって亜鉛めっきを施した後、更に合金化炉で
めっき被膜の合金化処理を施す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である。(4) A fourth invention is characterized in that after galvanizing by the manufacturing method according to the first to third inventions, an alloying treatment is further performed on the plated film in an alloying furnace. This is a method for producing a galvanized steel sheet.
【００１５】[0015]
【発明の実施の形態】以下に本発明を詳細に説明する。
まず、本発明の鋼板成分の限定理由について述べる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
First, the reasons for limiting the steel sheet components of the present invention will be described.
【００１６】(1)Si：0.1％以上。 Siは鋼板を高強度化し、かつ材質を安定化させるために
添加する。上記の目的のためには、0.1％以上のSiが必
要である。(1) Si: 0.1% or more. Si is added to strengthen the steel sheet and stabilize the material. For the above purpose, 0.1% or more of Si is required.
【００１７】(2)P：0.01％以上。 PもSiと同様、鋼板を高強度化するために添加するが、
上記効果を得るためには0.01％以上の添加が必要であ
る。(2) P: 0.01% or more. P is added to increase the strength of the steel sheet as well as Si,
To obtain the above effect, 0.01% or more must be added.
【００１８】次に、連続式溶融亜鉛めっきラインにおけ
る製造方法の限定理由について述べる。Next, the reasons for limiting the production method in the continuous galvanizing line will be described.
【００１９】(3)加熱帯を２つ以上の区域に分け、それ
ぞれの区域における空燃比を制御する。(3) The heating zone is divided into two or more zones, and the air-fuel ratio in each zone is controlled.
【００２０】Siが0.1％以上またはPが0.01％以上添加さ
れている鋼板は、［従来技術］の項で述べたとおり、鋼
板表面でSiおよびＰの選択酸化が起こり、亜鉛めっきの
濡れ性および合金化処理性が低下する。そこで、還元工
程の前に鋼板表面にFe酸化物を形成し、SiおよびＰの拡
散を抑制することによって、これらの成分の選択酸化を
抑制することが必要となる。しかし、予熱帯および加熱
帯で酸化物を形成し、還元帯でその酸化物を還元する従
来の方法では、ロールによるピックアップの問題が発生
する。In a steel sheet to which Si is added in an amount of 0.1% or more or P is added in an amount of 0.01% or more, selective oxidation of Si and P occurs on the surface of the steel sheet as described in the section of [Prior Art], and the wettability of zinc plating and The alloying processability decreases. Therefore, it is necessary to suppress the selective oxidation of these components by forming Fe oxide on the steel sheet surface before the reduction step and suppressing the diffusion of Si and P. However, in the conventional method of forming an oxide in the pre-tropical zone and the heating zone and reducing the oxide in the reduction zone, a problem of pick-up by a roll occurs.
【００２１】そこで、本発明者らは、加熱帯を２つ以上
の区域に分け、それぞれの区域における空燃比を制御す
ることによって、加熱帯の中で酸化＋還元工程を完了し
て、ロールへのピックアップを防止する方法を考えだし
た。本発明者らは、実験室での検討と実際の連続式溶融
亜鉛めっきラインでの検討を重ね、加熱帯における鋼板
温度と空燃比の適正範囲を求め、本発明を完成した。そ
の内容は以下のとおりである。Therefore, the present inventors divided the heating zone into two or more zones, and controlled the air-fuel ratio in each zone, thereby completing the oxidation and reduction steps in the heating zone, and Figured out ways to prevent pickup. The present inventors have repeated studies in a laboratory and studies in an actual continuous hot-dip galvanizing line, and determined an appropriate range of a steel sheet temperature and an air-fuel ratio in a heating zone, thereby completing the present invention. The contents are as follows.
【００２２】(4)加熱帯において、鋼板温度が500℃未満
である区域での空燃比を1.00以上1.3以下、鋼板温度が5
70℃以上になる区域での空燃比を0.80以上1.1以下とす
る。(4) In the heating zone, the air-fuel ratio is 1.00 or more and 1.3 or less in an area where the steel sheet temperature is less than 500 ° C.
The air-fuel ratio in the area where the temperature is 70 ° C or higher is set to 0.80 or more and 1.1 or less.
【００２３】本発明者らの検討の結果、570℃未満の温
度域で生成した鋼板表面上の酸化物は、570℃以上の温
度域で生成した酸化物と比較して、鋼板から剥離しにく
いことが明らかになった。したがって、ピックアップ性
の観点から、酸化物の生成は570℃未満、好ましくは500
℃未満の温度域で行われることが好ましい。一方、加熱
帯において、鋼板上に酸化物を安定して生成するために
は、1.00以上1.3以下の空燃比が必要であることも判明
した。その理由は、空燃比1.00未満では酸化物を安定し
て形成させることが困難であり、1.3より大きいと、酸
化物が急速に生成しすぎて加熱炉内で還元しきれなくな
り、ロールのピックアップが発生するためである。As a result of the study by the present inventors, oxides on the surface of the steel sheet generated in a temperature range of less than 570 ° C. are less likely to be separated from the steel sheet than oxides generated in a temperature range of 570 ° C. or more. It became clear. Therefore, from the viewpoint of pick-up properties, the generation of oxide is less than 570 ° C., preferably 500
It is preferable to be carried out in a temperature range of less than ° C. On the other hand, it was also found that an air-fuel ratio of 1.00 or more and 1.3 or less was necessary in order to stably generate oxides on the steel sheet in the heating zone. The reason is that if the air-fuel ratio is less than 1.00, it is difficult to form oxides stably.If the air-fuel ratio is more than 1.3, the oxides are generated too quickly and cannot be reduced in the heating furnace, and the roll pickup becomes difficult. Because it occurs.
【００２４】このようにして生成させた酸化物を、加熱
帯の後半部分で還元する。そのためには、この区域の空
燃比を0.80以上1.1以下とすることが好ましい。その理
由は、空燃比が1.1より大きいと加熱帯で還元が十分に
行われずにピックアップが発生し、0.80未満では燃焼の
効率が低下し、製造コストが増大するためである。The oxide thus produced is reduced in the latter half of the heating zone. For this purpose, it is preferable that the air-fuel ratio in this area be 0.80 or more and 1.1 or less. The reason is that if the air-fuel ratio is larger than 1.1, the reduction is not sufficiently performed in the heating zone, causing pickup, and if the air-fuel ratio is less than 0.80, the combustion efficiency is reduced and the production cost is increased.
【００２５】(5)加熱帯で鋼板を加熱する手段として直
火還元加熱方式を用いる。本発明は、加熱帯において、
鋼板表面の酸化と還元を両方行うことを特徴としてい
る。したがって、炎が還元炎と酸火炎からなり、空燃比
を変えることによりその比率を任意に制御できる直火還
元加熱方式が、本発明に適している。(5) As a means for heating the steel sheet in the heating zone, a direct fire reduction heating system is used. The present invention provides, in a heating zone,
It is characterized by performing both oxidation and reduction of the steel sheet surface. Therefore, a direct flame reduction heating system in which the flame is composed of a reducing flame and an acid flame and whose ratio can be arbitrarily controlled by changing the air-fuel ratio is suitable for the present invention.
【００２６】(6)加熱帯において、鋼板温度が400℃以上
650℃以下である間に、鋼板とロールが連続して接触す
る時間が0.5sec未満である。(6) In the heating zone, the temperature of the steel sheet is 400 ° C. or more.
While the temperature is 650 ° C. or less, the continuous contact time between the steel sheet and the roll is less than 0.5 sec.
【００２７】酸化物がロールによってピックアップされ
ることを防止するためには、鋼板上に酸化物が形成され
ている間は、鋼板がロールに接触する機会をなるべく少
なくすることが必要である。このため、本発明では、酸
化物は加熱帯の中で形成され還元されることを基本とし
ているが、加熱帯の内部においても、なるべく鋼板とロ
ールの接触時間を短くする方が好ましい。検討の結果、
ロールによるピックアップ量は、ロールと鋼板の温度、
接触圧力、接触時間に依存し、鋼板とロールが連続して
接触する時間が0.5sec未満であれば、ピックアップ量は
無視できる程度に小さくなることが判明した。また、本
発明において、酸化物が厚く生成されるのは鋼板温度が
400℃以上650℃以下の範囲である。そこで、この温度域
において、鋼板とロールが連続して接触する時間の上限
を0.5secとする。In order to prevent the oxide from being picked up by the roll, it is necessary to minimize the chance of the steel sheet contacting the roll while the oxide is formed on the steel sheet. For this reason, in the present invention, the oxide is basically formed and reduced in the heating zone, but it is preferable that the contact time between the steel sheet and the roll is shortened as much as possible even in the heating zone. As a result of the examination,
The amount of pickup by the roll is the temperature of the roll and the steel plate,
It was found that depending on the contact pressure and the contact time, if the continuous contact time between the steel sheet and the roll was less than 0.5 sec, the pickup amount was negligibly small. In the present invention, the oxide is generated thickly when the steel sheet temperature is increased.
It is in the range from 400 ° C to 650 ° C. Therefore, in this temperature range, the upper limit of the continuous contact time between the steel sheet and the roll is set to 0.5 sec.
【００２８】本発明は、連続式溶融亜鉛めっきラインで
溶融亜鉛めっき鋼板あるいは合金化溶融亜鉛めっき鋼板
を製造する場合を対象としている。本発明において、前
記で規定しない鋼板の成分、鋼の溶製、熱間圧延、酸
洗、冷間圧延、前記で規定しない溶融亜鉛めっき条件お
よび合金化処理条件等は特に限定されず、通常行われて
いる方法でよい。The present invention is directed to a case where a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet is manufactured in a continuous hot-dip galvanizing line. In the present invention, the components of the steel sheet not specified above, smelting of steel, hot rolling, pickling, cold rolling, hot dip galvanizing conditions and alloying treatment conditions not specified above are not particularly limited, and are not usually specified. You can do it in the way you are.
【００２９】溶融亜鉛めっきの前にFeあるいはNiを主成
分としたプレめっきを施し、めっきの濡れ性や密着性、
および合金化処理性を更に改善する方法も、本発明の範
囲内に含まれる。Prior to the hot-dip galvanizing, a pre-plating containing Fe or Ni as a main component is performed, and the wettability and adhesion of the plating,
Methods for further improving the alloying processability are also included in the scope of the present invention.
【００３０】また、溶融亜鉛めっきあるいは合金化処理
の後に、FeあるいはNiを主成分とした上層めっきを施
し、プレス成形性を改善する方法も、本発明の範囲内に
含まれる。Also, a method of improving the press formability by subjecting the upper layer to a main component of Fe or Ni after the hot-dip galvanizing or alloying treatment is included in the scope of the present invention.
【００３１】[0031]
【実施例】本発明の実施例を以下に示す。表１に示す鋼
を溶製し、鋳造して得られたスラブを板厚3.0mmに熱間
圧延した。熱間圧延は、仕上げ温度を900℃とし、仕上
げ圧延後650℃で巻き取った。その後、酸洗し、更に冷
間圧延して板厚1.0mmの鋼板を得た。Embodiments of the present invention will be described below. A slab obtained by melting and casting the steel shown in Table 1 was hot-rolled to a thickness of 3.0 mm. The hot rolling was performed at a finishing temperature of 900 ° C., and was wound at 650 ° C. after the finish rolling. Thereafter, the plate was pickled and further cold-rolled to obtain a steel plate having a thickness of 1.0 mm.
【００３２】[0032]
【表１】 [Table 1]
【００３３】次いで、前記で得た鋼板を用い、予熱帯、
加熱帯、ラジアントチューブ方式の還元帯、冷却帯、め
っき浴、合金化炉の設備を備えた連続式溶融亜鉛めっき
ラインで溶融亜鉛めっき鋼板および合金化溶融亜鉛めっ
き鋼板を製造した。加熱帯を２つの区域に分け、それぞ
れの区域における空燃比を制御した。それぞれの区域に
おける空燃比と２つの区域の境界における鋼板温度を表
２に示した。鋼板の加熱には直火還元加熱バーナーを使
用した。加熱帯における鋼板表面の酸化および還元に引
き続き、焼鈍、冷却、両面への溶融めっき、ガスワイピ
ングを行った。めっき付着量は片面あたり45〜55g/m2に
なるようにした。製造した鋼板の一部は、合金化処理を
施さずに溶融亜鉛めっき鋼板とし、残りは引き続き合金
化処理を施し、合金化溶融亜鉛めっき鋼板とした。Next, using the steel sheet obtained above,
A hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet were manufactured in a continuous hot-dip galvanizing line equipped with a heating zone, a radiant tube type reduction zone, a cooling zone, a plating bath, and an alloying furnace. The heating zone was divided into two zones, and the air-fuel ratio in each zone was controlled. Table 2 shows the air-fuel ratio in each zone and the steel sheet temperature at the boundary between the two zones. An open flame reduction heating burner was used to heat the steel sheet. Following oxidation and reduction of the steel sheet surface in the heating zone, annealing, cooling, hot-dip plating on both sides, and gas wiping were performed. The coating weight was set to 45 to 55 g / m 2 per one side. A part of the manufactured steel sheet was formed into a hot-dip galvanized steel sheet without being subjected to an alloying treatment, and the rest was continuously subjected to an alloying treatment to obtain an alloyed hot-dip galvanized steel sheet.
【００３４】このようにして作製したサンプルを、以下
に示す方法で評価した。溶融亜鉛めっき鋼板について
は、不めっきの有無を評価した。目視観察を行った結
果、不めっきが認められなかったものを合格（○）、認
められたものを不合格（×）とした。The sample thus produced was evaluated by the following method. The hot-dip galvanized steel sheet was evaluated for the presence or absence of non-plating. As a result of the visual observation, those in which no plating was not recognized were evaluated as pass (（), and those in which no plating was recognized were evaluated as unacceptable (x).
【００３５】合金化処理性については、連続式溶融亜鉛
めっきラインにおけるラインスピードと合金化温度を一
定とし、合金化処理後のめっき被膜中のFe濃度によって
評価した。このとき、ラインスピードは75mpmとし、合
金化処理温度は550℃とした。めっき被膜の付着量およ
びFe濃度は、被膜を塩酸で溶解し、ICPによって測定し
た。With respect to the alloying property, the line speed and the alloying temperature in the continuous hot-dip galvanizing line were fixed, and the Fe concentration in the plated film after the alloying treatment was evaluated. At this time, the line speed was 75 mpm, and the alloying treatment temperature was 550 ° C. The adhesion amount and Fe concentration of the plating film were measured by dissolving the film with hydrochloric acid and using ICP.
【００３６】また、ピックアップ性については、上記の
鋼板を通板させた後、酸化物のピックアップが認められ
た場合は不合格（×）、認められなかった場合は合格
（○）とした。Regarding the pick-up property, after passing the steel sheet, if the pick-up of the oxide was recognized, it was rejected (x), and if not, it was passed (o).
【００３７】評価結果を、表２に併せて記載した。The evaluation results are also shown in Table 2.
【００３８】[0038]
【表２】 [Table 2]
【００３９】以下、表２に示した実施例について述べ
る。実験No.1〜4は本発明例である。鋼板は予熱帯を通
過した後、加熱帯区域１を通過するが、ここでの空燃比
は1.06〜1.25の範囲にあった。その後、鋼板は加熱帯区
域２に進入するが、２つの区域の境界における鋼板温度
は525〜540℃であった。加熱帯区域２での空燃比は0.87
〜1.01の範囲であった。このようにして製造された鋼板
は、ピックアップを起こすことがなく、めっきの濡れ性
も良好であった。また、合金化処理性にも優れていた。Hereinafter, the embodiment shown in Table 2 will be described. Experiment Nos. 1 to 4 are examples of the present invention. After passing through the pre-tropical zone, the steel sheet passes through heating zone zone 1, where the air-fuel ratio was in the range of 1.06 to 1.25. Thereafter, the steel sheet enters heating zone zone 2, where the steel strip temperature at the boundary of the two zones was 525-540 ° C. The air-fuel ratio in heating zone 2 is 0.87
It was in the range of ~ 1.01. The steel sheet produced in this manner did not cause pickup and had good wettability for plating. Also, the alloying property was excellent.
【００４０】実験No.5〜12は比較例である。実験No.5、
7、8は、加熱帯区域２の空燃比が高すぎたため、めっき
の濡れ性と合金化処理性は良好であるが、ロールによる
ピックアップが認められた。Experiment Nos. 5 to 12 are comparative examples. Experiment No. 5,
In Nos. 7 and 8, although the air-fuel ratio in the heating zone area 2 was too high, the wettability of the plating and the alloying property were good, but pick-up by rolls was recognized.
【００４１】実験No.6は、加熱帯区域１の空燃比が高す
ぎたため、めっきの濡れ性と合金化処理性は良好である
が、ロールによるピックアップが認められた。In Experiment No. 6, although the air-fuel ratio in the heating zone 1 was too high, the wettability of the plating and the alloying treatment were good, but pick-up by a roll was recognized.
【００４２】実験No.9〜12は、加熱帯区域１の空燃比が
低すぎたため、めっきの濡れ性と合金化処理性が劣っ
た。In Experiments Nos. 9 to 12, the air-fuel ratio of the heating zone 1 was too low, so that the wettability of the plating and the alloying property were inferior.
【００４３】[0043]
【発明の効果】以上示したように、本発明によれば、従
来製造が困難であった、Si、P含有鋼板を下地とした溶
融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板を、
連続式溶融亜鉛めっきラインを用いて、低コストで生産
性良く製造することができる。下地鋼板にSi、Pを添加す
ることにより、鋼板組織をマルテンサイト相を含む複合
組織や残留オーステナイト相を含む組織にすることがで
き、引張強度が35kg/mm2以上の高強度で、かつプレス成
形性に優れた材質を得ることができる。As described above, according to the present invention, a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet that are conventionally difficult to manufacture,
By using a continuous galvanizing line, it can be manufactured at low cost and with high productivity. Si in the base steel plate, by the addition of P, can be a steel sheet structure in the tissue containing the composite structure and residual austenite phase containing martensite phase, a tensile strength at 35 kg / mm 2 or more high strength and press A material excellent in formability can be obtained.
【００４４】本発明によって製造された鋼板は、表面に
溶融亜鉛めっき皮膜を有しているために耐食性に優れ、
高強度でかつプレス成形性に優れているため、自動車部
品をはじめ多くの用途に使用することができる。The steel sheet produced according to the present invention has excellent corrosion resistance because it has a hot-dip galvanized film on its surface.
Since it has high strength and excellent press moldability, it can be used for many applications including automobile parts.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 稲垣 淳一 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 (72)発明者 鷺山 勝 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 Ｆターム(参考） 4K027 AA02 AA23 AB02 AB28 AB42 AC12 AC73 AD25 AE12 AE18 AE33 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Junichi Inagaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masaru Sagiyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun 4K027 AA02 AA23 AB02 AB28 AB42 AC12 AC73 AD25 AE12 AE18 AE33
Claims (4)
上のうちの少なくとも一種を含む鋼板を、予熱帯、加熱
帯、ラジアントチューブ方式の還元帯、冷却帯を備える
熱処理炉で熱処理し、その後めっき浴に浸漬して亜鉛め
っきを施す溶融亜鉛めっき鋼板の製造方法において、前
記加熱帯を２つ以上の区域に分け、鋼板温度が500℃未
満である区域での空燃比を1.00以上1.3以下、鋼板温度
が570℃以上になる区域での空燃比を0.80以上1.1以下と
することを特徴とする、溶融亜鉛めっき鋼板の製造方
法。1. A heat treatment furnace having a pre-tropical zone, a heating zone, a radiant tube type reduction zone, and a cooling zone, comprising a steel sheet containing at least one of 0.1% or more of Si and 0.01% or more of P in weight%. In a method for producing a hot-dip galvanized steel sheet that is heat-treated and then immersed in a plating bath to perform galvanization, the heating zone is divided into two or more areas, and the air-fuel ratio in an area where the steel sheet temperature is less than 500 ° C. is 1.00. A method for producing a hot-dip galvanized steel sheet, wherein the air-fuel ratio in an area where the steel sheet temperature is 570 ° C. or more is 0.80 or more and 1.1 or less.
して直火還元加熱方式を用いることを特徴とする、請求
項１に記載の溶融亜鉛めっき鋼板の製造方法。2. The method for producing a hot-dip galvanized steel sheet according to claim 1, wherein in the heating zone, a direct fire reduction heating method is used as a means for heating the steel sheet.
50℃以下である間に、鋼板とロールが連続して接触する
時間が0.5sec未満であることを特徴とする、請求項１、
請求項２に記載の溶融亜鉛めっき鋼板の製造方法。3. In the heating zone, the temperature of the steel sheet is 400 ° C. or more.
The time in which a steel plate and a roll contact continuously during less than 50 degreeC is less than 0.5 second, The characterized by the above-mentioned,
A method for producing a galvanized steel sheet according to claim 2.
っきを施した後、更に合金化炉でめっき被膜の合金化処
理を施す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。4. A method for producing a galvannealed steel sheet, comprising, after galvanizing according to the production method of claims 1 to 3, further performing an alloying treatment on the plating film in an alloying furnace.
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| JP20154899A JP3598889B2 (en) | 1999-07-15 | 1999-07-15 | Method for producing hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel sheet |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20154899A JP3598889B2 (en) | 1999-07-15 | 1999-07-15 | Method for producing hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel sheet |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007262464A (en) * | 2006-03-28 | 2007-10-11 | Jfe Steel Kk | Method for producing hot dip galvanized steel sheet |
| JP2008001934A (en) * | 2006-06-21 | 2008-01-10 | Kobe Steel Ltd | Hot-dip galvanization equipment |
| WO2019082542A1 (en) * | 2017-10-26 | 2019-05-02 | 株式会社神戸製鋼所 | Production method for molten zinc-plated steel sheet |
| CN112575155A (en) * | 2020-12-03 | 2021-03-30 | 攀钢集团攀枝花钢铁研究院有限公司 | Process for controlling decarburization layer of steel billet |
-
1999
- 1999-07-15 JP JP20154899A patent/JP3598889B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007262464A (en) * | 2006-03-28 | 2007-10-11 | Jfe Steel Kk | Method for producing hot dip galvanized steel sheet |
| JP2008001934A (en) * | 2006-06-21 | 2008-01-10 | Kobe Steel Ltd | Hot-dip galvanization equipment |
| JP4718381B2 (en) * | 2006-06-21 | 2011-07-06 | 株式会社神戸製鋼所 | Hot dip galvanizing equipment |
| WO2019082542A1 (en) * | 2017-10-26 | 2019-05-02 | 株式会社神戸製鋼所 | Production method for molten zinc-plated steel sheet |
| JP2019077933A (en) * | 2017-10-26 | 2019-05-23 | 株式会社神戸製鋼所 | Production method of galvanized steel sheet |
| CN112575155A (en) * | 2020-12-03 | 2021-03-30 | 攀钢集团攀枝花钢铁研究院有限公司 | Process for controlling decarburization layer of steel billet |
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| Publication number | Publication date |
|---|---|
| JP3598889B2 (en) | 2004-12-08 |
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