JP2004068051A - High strength hot-dip galvanized steel sheet and its manufacturing method - Google Patents
High strength hot-dip galvanized steel sheet and its manufacturing method Download PDFInfo
- Publication number
- JP2004068051A JP2004068051A JP2002226267A JP2002226267A JP2004068051A JP 2004068051 A JP2004068051 A JP 2004068051A JP 2002226267 A JP2002226267 A JP 2002226267A JP 2002226267 A JP2002226267 A JP 2002226267A JP 2004068051 A JP2004068051 A JP 2004068051A
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel sheet
- hot
- ferrite
- rolling
- 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
Images
Landscapes
- Metal Rolling (AREA)
- Coating With Molten Metal (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【0001】
【発明の属する技術分野】
この発明は、自動車ボディに用いられる衝突安全を確保するための部品等であって耐食性が重要な部位の素材として好適な成形性に優れる高強度溶融亜鉛めっき鋼板及びその製造方法に関するものである。
【0002】
【従来の技術】
近年、自動車の安全及び軽量化対策としての高強度鋼板への要望が益々高くなっている。
しかしながら、鋼板を高強度化していくと成形性が問題になってくる。特に伸びフランジ成形やバ−リング成形に大きく影響する局部伸びと、張り出し成形への影響が大きい一様伸びを高めるのは重要なことである。
なお、図1は、鋼板の引張試験を実施したときの公称応力−公称歪み曲線であり、局部伸びと一様伸びを把握することができる。
【0003】
高強度冷延鋼板の製造方法としては、例えば特開平7−188767号公報にベイナイト主体の金属組織にすることで伸びフランジ性を改善する製造方法が開示されている。
しかしながら、ベイナイト主体の組織だけでは一様伸びが低いという問題があった。
更に、上記特開平7−188767号公報に記載の高強度冷延鋼板の製造方法では高強度を得るために焼鈍後100℃/c以上の冷却速度が必要で、冷却中に生じる歪により平坦度を確保することが困難であるとの問題もあった。
【0004】
また、特開平9−263838号公報には、鋼板の金属組織をフェライトとベイナイトの混合組織にして穴拡げ性を改善する方法が開示されている。
しかしながら、この方法でも局部伸び及び一様伸びの確保は不十分である。また、何れも耐食性を考慮しておらず、溶融亜鉛めっきを施すには困難な製造条件である。
【0005】
【発明が解決しようとする課題】
このようなことから、本発明が目的としたのは、前述したような従来技術の問題点を解決し、高強度を有すると共に一様伸びと局部伸びで表現される成形性が良好な高強度溶融亜鉛めっき鋼板及びその製造方法を提供することであった。
【0006】
【課題を解決するための手段】
本発明者らは上記目的を達成すべく鋭意研究を行った結果、高強度と一様伸びで表現される成形性が両立した溶融亜鉛めっき鋼板を実現するためには、母材鋼板の金属組織を、フェライトが体積率で30%以上を占め、更に粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトの何れか1種以上を含むフェライト粒の数が総フェライトの数の20%以上である組織とすることが重要であるとの知見を得ることができた。
【0007】
即ち、本発明者らは、まず、局部伸びでの破断の起点はフェライト粒界に存在する硬質なマルテンサイトや粗大で脆い炭化物を含むパ−ライトであることを見出した。更に、高強度を得るために必要なマルテンサイトやセメンタイトや残留オ−ステナイトは、フェライト粒内にあれば割れの起点になりにくいことも明らかとした。
そして、この解明事項と高強度が得られる母材鋼板組織の検討、並びに母材鋼板に好ましい金属組織が得られる溶融亜鉛めっき手段の検討により、高強度と一様伸びで表現される成形性が両立した溶融亜鉛めっき鋼板を実現する上での前記母材鋼板組織の有効性を確認するに至ったわけである。
【0008】
本発明は、上記知見事項等を基に完成されたものであり、次の▲1▼〜▲3▼項に示す耐食性が重要な部位の素材として好適な成形性に優れる高強度溶融亜鉛めっき鋼板及びその製造方法を提供するものである。
▲1▼ C:0.005 〜0.20%(以降、 成分割合を示す%は重量%とする),Si:0.5 %以下,Mn:0.7 〜3.0 %,P:0.10%以下,S:0.010 %以下,Al:0.001 〜0.20%,N:0.020 %以下を含むと共に残部が実質的にFe及び不可避的不純物から成り、かつ金属組織として、フェライトを体積率で30%以上有し、更に粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトの何れか1種以上を含むフェライト粒の数が総フェライトの数の20%以上である組織を持つ母材鋼板の表面に、溶融亜鉛めっき層を有して成ることを
特徴とする、高強度溶融亜鉛めっき鋼板。
▲2▼ C:0.005 〜0.20%,Si:0.5 %以下,Mn:0.7 〜3.0 %,P:0.10%以下,S:0.010 %以下,Al:0.001 〜0.20%,N:0.020 %以下を含み、更にTi:0.20%以下,Nb:0.20%以下,V:0.10%以下,B:0.01%以下,Cr:1.0 %以下,Mo:1.0 %以下,Cu:1.0 %以下,Ni:1.0 %以下,Ca:0.01%以下の1種以上を含むと共に残部が実質的にFe及び不可避的不純物から成り、かつ金属組織として、フェライトを体積率で30%以上有し、更に粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトの何れか1種以上を含むフェライト粒の数が総フェライトの数の20%以上である組織を持つ母材鋼板の表面に、溶融亜鉛めっき層を有して成ることを特徴とする、
高強度溶融亜鉛めっき鋼板。
▲3▼ 前記▲1▼項又は▲2▼項に記載の成分組成を有した鋼片を、1050℃以上に加熱した後に粗圧延を開始し、粗圧延終了後、そのままあるいは粗バ−の加熱又は温度保定を実施してから仕上圧延を開始し、仕上温度740〜1030℃で圧延終了した後、5℃/s以上の平均冷却速度で冷却して700℃以下で巻き取り、更に巻き戻してからそのまま或いはスキンパス圧延,酸洗を施した後に冷間圧延を施し、次いで720〜900℃の温度範囲で5秒以上保持する焼鈍を行った後、2〜30℃/sの平均冷却速度で460〜600℃まで冷却して該温度範囲で10〜90秒保持し、更に冷却してから溶融亜鉛めっきを施すと共に、更に必要に応じて合金化処理を施し、続く冷却過程において200℃から100℃以下までを300秒以内で冷却することを特徴とす
る、高強度溶融亜鉛めっき鋼板の製造方法。
【0009】
【発明の実施の形態】
次に、本発明において溶融亜鉛めっき鋼板における母材鋼板の金属組織,鋼片又は母材鋼板の成分組成、並びに溶融亜鉛めっき鋼板の製造条件を前記の如くに限定した理由を説明する。
(A) 母材鋼板の金属組織
母材鋼板の金属組織は本発明の重要な要素であり、母材鋼板を、フェライトが体積率で30%以上を占め、更に粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトの何れか1種以上を有しているフェライト粒の数が総フェライトの数の20%以上となる金属組織とすることにより、優れた一様伸びと局部伸びを有する高強度溶融亜鉛めっき鋼板が得られる。
【0010】
なお、フェライトはそれ自体優れた延性を有しているため、鋼板に優れた一様伸びを確保するためには体積率で30%以上必要である。フェライトが体積率で30%未満である場合には、優れた一様伸びを確保できない。鋼板組織に占めるフェライトの体積率は、好ましくは50%以上、更に好ましくは70%以上である。
【0011】
ただ、フェライトのみでは高強度の確保は困難であり、従って硬質な第2相を生成させて鋼板の高強度を図る必要がある。
しかし、フェライト粒界に存在する硬質なマルテンサイトや脆い炭化物であるセメンタイト、又は成形により硬質なマルテンサイトに変化する残留オ−ステナイトは局部伸びの割れの起点となりやすい。そのため、これらはフェライト粒内に存在するのが好ましく、粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトの何れか1種以上を有しているフェライト粒の数が総フェライトの数の20%以上である必要がある。なお、このようなフェライト粒の数は、好ましくは30%以上、更には50%以上が望ましい。
【0012】
(B) 鋼片乃至は母材鋼板の化学組成
C: Cは高張力を得るのに重要な成分である。Cの含有量が 0.005%未満では必要な高張力が得られず、また0.20%を超えてCを含有させると靱性や溶接性が低下すると共にフェライト生成量が不足する。従って、C含有量を0.005 〜0.20%と定めたが、好ましくは0.03〜0.12%に調整するのが良い。
【0013】
Si: Siも鋼板を高強度化するのに有効な成分であるが、溶融亜鉛めっきを施す際の不めっきや、合金化処理時の処理不足の原因となる。従って、Si含有量は0.5 %以下と定めたが、好ましくは0.10%未満に調整するのが良い。
【0014】
Mn: Mnは変態強化を促進して高強度化を図るのに有効な成分であり、そのためには 0.7%以上含有させることが必要である。また、3.0 %を超えてMnを含有させるとフェライトが生成しにくくなると同時にバンド組織が発達して局部伸びが低下する。従って、Mn含有量については 0.7〜 3.0%と定めたが、好ましくは0.9〜 3.0%、更に好ましくは 1.3〜 3.0%に調整するのが良い。
【0015】
P: Pは靱性を劣化させる好ましくない元素である。従って、その許容量を確認し、P含有量を0.10%以下と定めた。
S: SはMnSとなり、曲げ性を劣化させる。従って、その許容量を確認し、Sの含有量を 0.010%以下と定めたが、好ましくは0.0040%以下に、より好ましくは0.0015%以下とするのが良い。
【0016】
Al: Alは脱酸のために添加される元素であるが、その効果は 0.001%未満では不十分であり、また0.20%を超えて含有させても効果が飽和し経済的に不利となる。従って、Al含有量は 0.001〜0.20%と定めた。
N: Nは、連続鋳造中に窒化物を形成してスラブのひび割れの原因となるので、その含有量は低い方が好ましい。従って、その許容量を確認し、N含有量は0.020 %以下と定めた。
【0017】
Ti,Nb,V,B: Ti,Nb,V,Bは再結晶を遅らせて結晶粒を微細化させる効果を有しているので、必要に応じて1種以上が含有せしめられる。しかしながら、その効果は、Ti含有量が0.20%を超え、Nb含有量が0.20%を超え、V含有量が0.10%を超え、そしてB含有量が 0.010%を超えると飽和してしまいコスト的に不利となる。そのため、Ti含有量は0.20%以下、Nb含有量は0.20%以下、V含有量は0.10%以下、B含有量は 0.010%以下とそれぞれ定めた。
【0018】
Cr,Mo: Cr及びMoには何れもMnと同様にオ−ステナイトを安定化することで変態強化を促進する働きがあり、鋼板の高強度化に有効であるので必要に応じて1種以上が含有せしめられる。しかし、Cr含有量が 1.0%を超え、そしてMo含有量が 1.0%を超えると鋼板の表面処理性に問題が出てくる。従って、Cr含有量は1.0 %以下、Mo含有量は 1.0%以下とそれぞれ定めた。
【0019】
Cu,Ni: Cu及びNiは腐食抑制効果があり、表面に濃化し水素の侵入を抑え、遅れ破壊を抑制する働きがあるので、必要に応じて1種以上が含有される。しかしながら、何れもその含有量が 1.0%を超えると前記効果は飽和しコスト的に不利となる。従って、Cu含有量もNi含有量も 1.0%以下とそれぞれ定めた。
【0020】
Ca: CaはSと結合し、硫化物を球状化させることにより局部延性を向上させる効果があるので、必要に応じて添加される。しかしながら、0.01%を超えて含有させてもその効果は飽和し、コスト的に不利となることから、Ca含有量は0.01%以下と定めた。
【0021】
なお、上記以外の組成はFe及び不可避的不純物である。
そして、上記組成の鋼は、例えば転炉,電気炉又は平炉等により溶製される。鋼種もリムド鋼,キャップド鋼,セミキルド鋼又はキルド鋼の何れでも良い。更に、鋼片の鋳造は“造塊−分塊圧延”あるいは“連続鋳造”の何れの手段によっても構わない。
また、本発明に係る溶融亜鉛めっき鋼板は、亜鉛系めっき鋼板であれば格別にそのめっき層の種類が問われるものではなく、溶融亜鉛めっき層,溶融亜鉛合金めっき層,合金化溶融亜鉛めっき層等の何れであっても構わない。また、めっき層は鋼板の両面に施されていても良いし、片面に施されていても良い。
【0022】
(C) 製造条件
本発明に係る“耐食性が重要な部位の素材として好適な成形性に優れる高強度溶融亜鉛めっき鋼板”を製造するには、まず本発明が規定する成分組成の鋼片を1050℃以上に加熱後粗圧延を開始し、粗圧延終了後、そのまま或いは必要に応じて粗バ−を加熱又は温度保定を施してから仕上圧延を開始し、仕上温度740〜1030℃で圧延を終了後、平均冷却速度5℃/s以上で冷却し、700℃以下で巻き取る熱間圧延を施す。
【0023】
1050℃以上への鋼片の加熱は、仕上温度を確保するのに必要である。そして、仕上温度740℃以上は、変態点以下の圧延に伴ってフェライトが粗大化するのを抑制するのに必要な条件であり、また1030℃以下の仕上温度は熱延板での組織を微細化して冷延板焼鈍後に十分なフェライトを生成させるのに必要な条件である。
なお、仕上温度を確保するために仕上圧延前に粗バ−を加熱或いは温度保定することは有効である。また、粗バ−を接合して連続圧延を施しても何ら問題はない。
熱間圧延に際し、加熱炉に挿入する鋳片は“鋳造後の高温ままでのスラブ”でも“室温で放置されたスラブ”でも構わない。
【0024】
仕上圧延を終了した後は、バンド状組織軽減のために平均冷却速度5℃/s以上で冷却し、700℃以下で巻き取る。巻取り温度が700℃を上回ると製品においても曲げ性を低下させるバンド状組織が発達するので好ましくない。
【0025】
熱間圧延後は、必要に応じて平坦矯正のためのスキンパス圧延やスケ−ル除去のための酸洗を施し、好ましくは圧下率30%以上の冷間圧延を施して焼鈍(連続焼鈍)及び溶融亜鉛めっきを施す。焼鈍では、720〜900℃の温度範囲で5秒以上保持する処理を行った後、2〜30℃/sの冷却速度で460〜600℃まで冷却して該温度範囲で10〜90秒保持し、更に冷却して溶融亜鉛めっきを施し、必要に応じて合金化処理を施してから、更に200℃から100℃以下まで300秒以内で急冷する。
【0026】
この場合、720℃未満の焼鈍温度及び5秒未満の加熱保持時間ではオ−ステナイト化が不十分で、高強度化に有効なフェライト粒内のセメンタイト又はマルテンサイト又は残留オ−ステナイトの量が少ない。一方、900℃を超える焼鈍温度では体積率で30%以上のフェライトが得られない。
焼鈍後は2℃/s以上の平均冷却速度で冷却を行うが、これは硬質相のフェライト粒界への析出を抑えるためである。また、平均冷却速度の上限は、平坦不良が出ないように60℃/sと定めた。
なお、焼鈍後の冷却過程では、フェライトと第2相を分離させるために460〜600℃の温度範囲で10〜90秒保持する必要がある。
【0027】
そして、上記冷却に続いて溶融亜鉛めっきを施し、必要に応じて合金化処理を行うが、これらの処理条件は特に限定されるものではない。
めっき処理後は、200℃から100℃以下までは300秒以内で冷却することが重要である。これにより、フェライト粒界に粗大なセメンタイトが析出するのが抑制できる。なお、200℃から100℃までの冷却は60秒以内とするのが好ましく、30秒以内がより望ましい。
【0028】
なお、めっき処理に続く冷却が終わった後、平坦矯正のため伸び率4%以下のスキンパスを施しても何ら問題がない。また、めっき層の上に潤滑作用のある皮膜を施しても構わない。
【0029】
【実施例】
表1に示す化学組成の鋼を転炉にて溶製した後、連続鋳造にてスラブとした。そして、そのスラブを表2に示す条件で熱間圧延し、 2.6mm厚の熱延鋼板を製造した。
次に、得られた熱延鋼板を酸洗してから 1.2mm厚まで冷間圧延し、その後、表3に示す条件の連続焼鈍及び溶融亜鉛めっきを施した。
溶融亜鉛めっき後、一部の材料では加熱による合金化処理を施し、めっき中のFeを重量割合で10%前後とした。
【0030】
【表1】
【0031】
【表2】
【0032】
【表3】
【0033】
このようにして得られた溶融亜鉛めっき鋼板につき、その母材をナイタル腐食して光学顕微鏡及びSEM観察、更に電子顕微鏡での観察にて金属組織の観察及び特定を行った。
また、圧延直角方向にJIS5号試験片と曲げ試験片を採取し、引張試験にて特性を調査した。
更に、粒内にセメンタイト又はマルテンサイト又は残留オ−ステナイトを1種以上含むフェライトの数は、ある任意の母材板厚断面でフェライトが100個入る領域を観察して、相当する粒数の割合(%)を把握した。
上述のようにして調査した金属組織及び材料特性を、表4に示す。
【0034】
【表4】
【0035】
表4に示される結果から明らかなように、本発明に係る溶融亜鉛めっき鋼板は一様伸びと局部伸びの両方とも高い値を示した。
これに対して、本発明で規定する金属組織が得られなかった材料は、一様伸び或いは局部伸びの一方又は両方が低い値となった。
また、Si含有量の高い試験番号30に係る溶融亜鉛めっき鋼板は、特性に問題は無かったが、めっき合金化処理不足が部分的に生じ、めっき品質に問題が認められた。
【0036】
【発明の効果】
以上に説明した如く、この発明によれば、優れた一様伸びと局部伸びを有し、ロッカ−インナ−等といった耐食性が必要な自動車の補強部品等に好適な溶融亜鉛めっき鋼板を安定して得ることができるなど、産業上有用な効果がもたらされる。
【図面の簡単な説明】
【図1】鋼板の引張試験を実施したときの公称応力−公称歪み曲線であり、局部伸びと一様伸びについての説明図でもある。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-strength hot-dip galvanized steel sheet which is excellent in formability and is suitable as a material for a part where corrosion resistance is important, such as a part used for an automobile body for ensuring collision safety and which is important as a material for a portion where corrosion resistance is important.
[0002]
[Prior art]
In recent years, demands for high-strength steel sheets as measures for safety and weight reduction of automobiles have been increasing.
However, as the strength of a steel sheet increases, formability becomes a problem. In particular, it is important to increase local elongation, which greatly affects stretch flange forming and burring forming, and uniform elongation, which greatly affects stretch forming.
FIG. 1 shows a nominal stress-nominal strain curve when a tensile test is performed on a steel sheet, and local elongation and uniform elongation can be grasped.
[0003]
As a method of manufacturing a high-strength cold-rolled steel sheet, for example, Japanese Patent Application Laid-Open No. 7-188767 discloses a method of improving stretch flangeability by forming a bainite-based metal structure.
However, there was a problem that uniform elongation was low only with a bainite-based structure alone.
Furthermore, in the method for producing a high-strength cold-rolled steel sheet described in JP-A-7-188767, a cooling rate of 100 ° C./c or more is required after annealing in order to obtain high strength. There was another problem that it was difficult to secure
[0004]
Japanese Patent Application Laid-Open No. 9-263838 discloses a method of improving the hole expandability by changing the metal structure of a steel sheet to a mixed structure of ferrite and bainite.
However, even with this method, it is insufficient to secure local elongation and uniform elongation. In addition, none of them considers corrosion resistance, which is a difficult production condition for hot-dip galvanizing.
[0005]
[Problems to be solved by the invention]
In view of the above, an object of the present invention is to solve the above-described problems of the prior art, and to provide a high strength having high strength and good moldability expressed by uniform elongation and local elongation. An object of the present invention is to provide a galvanized steel sheet and a method for producing the same.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, in order to realize a hot-dip galvanized steel sheet having both high strength and formability expressed by uniform elongation, the metallographic structure of the base steel sheet Is a structure in which ferrite occupies 30% or more by volume, and the number of ferrite grains containing at least one of cementite, martensite, and retained austenite in the grains is 20% or more of the total number of ferrites. Was found to be important.
[0007]
That is, the present inventors first found that the starting point of fracture at local elongation was pearlite containing hard martensite or coarse and brittle carbide present at the ferrite grain boundaries. Furthermore, it has been clarified that martensite, cementite, and residual austenite, which are necessary for obtaining high strength, are unlikely to be crack initiation points if present in ferrite grains.
By examining the elucidated items and the structure of the base steel sheet that can provide high strength, and the hot-dip galvanizing method that can obtain the preferred metal structure of the base steel sheet, the formability expressed by high strength and uniform elongation can be obtained. Thus, the effectiveness of the base steel sheet structure in realizing a compatible hot-dip galvanized steel sheet has been confirmed.
[0008]
The present invention has been completed on the basis of the above findings and the like, and is a high-strength hot-dip galvanized steel sheet excellent in formability suitable as a material for a portion where corrosion resistance is important as shown in the following items (1) to (3). And a method for producing the same.
{Circle around (1)} C: 0.005 to 0.20% (% indicating the component ratio is hereinafter referred to as% by weight), Si: 0.5% or less, Mn: 0.7 to 3.0%, P: 0 0.10% or less, S: 0.010% or less, Al: 0.001 to 0.20%, N: 0.020% or less, the balance being substantially composed of Fe and unavoidable impurities, and a metal structure A structure in which ferrite has a volume fraction of 30% or more, and the number of ferrite grains containing at least one of cementite, martensite, and retained austenite in the grains is 20% or more of the total number of ferrites A high-strength hot-dip galvanized steel sheet comprising a base steel sheet having a hot-dip galvanized layer on a surface thereof.
{Circle around (2)} C: 0.005 to 0.20%, Si: 0.5% or less, Mn: 0.7 to 3.0%, P: 0.10% or less, S: 0.010% or less, Al : 0.001 to 0.20%, N: 0.020% or less, Ti: 0.20% or less, Nb: 0.20% or less, V: 0.10% or less, B: 0.01 % Or less, Cr: 1.0% or less, Mo: 1.0% or less, Cu: 1.0% or less, Ni: 1.0% or less, Ca: 0.01% or less, and the balance Is substantially composed of Fe and unavoidable impurities, and has a metal structure of ferrite having a volume fraction of 30% or more, and further contains at least one of cementite, martensite, and residual austenite in grains. The surface of a base steel sheet with a structure in which the number of grains is 20% or more of the total number of ferrite Characterized by comprising a lead-plated layer,
High strength galvanized steel sheet.
(3) The steel slab having the component composition described in the above (1) or (2) is heated to 1050 ° C. or higher, and then rough rolling is started. Alternatively, the finish rolling is started after the temperature is held, and after finishing the rolling at the finishing temperature of 740 to 1030 ° C., it is cooled at an average cooling rate of 5 ° C./s or more, wound up at 700 ° C. or less, and further unwound. After cold rolling as it is or after skin pass rolling and pickling, and then annealing at a temperature of 720 to 900 ° C. for 5 seconds or more, 460 at an average cooling rate of 2 to 30 ° C./s.ま で 600 ° C., and kept at the temperature range for 10 to 90 seconds, further cooled, hot-dip galvanized, and further alloyed if necessary. Up to 300 A method for producing a high-strength hot-dip galvanized steel sheet, characterized by cooling within seconds.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the reason why the metal structure of the base steel sheet, the composition of the steel slab or the base steel sheet, and the manufacturing conditions of the hot-dip galvanized steel sheet in the present invention are limited as described above.
(A) Metal Structure of Base Steel Sheet The metal structure of the base steel sheet is an important element of the present invention. Ferrite occupies at least 30% by volume in the base steel sheet and further contains cementite or martensite or A high-strength melt having excellent uniform elongation and local elongation by forming a metal structure in which the number of ferrite grains having any one or more of retained austenite is 20% or more of the total number of ferrites. A galvanized steel sheet is obtained.
[0010]
Since ferrite itself has excellent ductility, a volume ratio of 30% or more is required to ensure excellent uniform elongation of the steel sheet. When the volume ratio of ferrite is less than 30%, excellent uniform elongation cannot be secured. The volume fraction of ferrite in the steel sheet structure is preferably at least 50%, more preferably at least 70%.
[0011]
However, it is difficult to secure high strength only with ferrite, and thus it is necessary to generate a hard second phase to increase the strength of the steel sheet.
However, hard martensite existing at ferrite grain boundaries, cementite which is a brittle carbide, or retained austenite which changes into hard martensite by molding tends to be a starting point of local elongation cracking. Therefore, these are preferably present in the ferrite grains, and the number of ferrite grains having at least one of cementite, martensite, and retained austenite in the grains is 20% or more of the total number of ferrites. Need to be The number of such ferrite grains is preferably at least 30%, more preferably at least 50%.
[0012]
(B) Chemical composition C of a billet or a base steel sheet: C is an important component for obtaining high tensile strength. If the content of C is less than 0.005%, the necessary high tensile strength cannot be obtained, and if the content of C exceeds 0.20%, the toughness and weldability are reduced and the amount of ferrite generated is insufficient. Therefore, the C content is determined to be 0.005 to 0.20%, but is preferably adjusted to 0.03 to 0.12%.
[0013]
Si: Si is also an effective component for increasing the strength of a steel sheet, but causes non-plating when hot-dip galvanizing is performed and insufficient processing during alloying processing. Therefore, the Si content is set to 0.5% or less, but is preferably adjusted to less than 0.10%.
[0014]
Mn: Mn is an effective component for promoting transformation strengthening and achieving high strength, and therefore, it is necessary to contain 0.7% or more. On the other hand, if the content of Mn exceeds 3.0%, ferrite is not easily formed, and at the same time, the band structure is developed and the local elongation is reduced. Therefore, the Mn content is determined to be 0.7 to 3.0%, but is preferably adjusted to 0.9 to 3.0%, and more preferably 1.3 to 3.0%.
[0015]
P: P is an undesirable element that degrades toughness. Therefore, the allowable amount was confirmed, and the P content was determined to be 0.10% or less.
S: S becomes MnS and deteriorates bendability. Therefore, the allowable amount was confirmed, and the S content was determined to be 0.010% or less, but it is preferably 0.0040% or less, and more preferably 0.0015% or less.
[0016]
Al: Al is an element added for deoxidation, but its effect is insufficient if less than 0.001%, and even if it exceeds 0.20%, the effect is saturated and economical. Disadvantageous. Therefore, the Al content was determined to be 0.001 to 0.20%.
N: N forms a nitride during continuous casting and causes cracking of the slab, so that its content is preferably low. Therefore, the allowable amount was confirmed, and the N content was determined to be 0.020% or less.
[0017]
Ti, Nb, V, B: Since Ti, Nb, V, and B have an effect of delaying recrystallization and refining crystal grains, one or more of them may be contained as necessary. However, the effect is that the Ti content exceeds 0.20%, the Nb content exceeds 0.20%, the V content exceeds 0.10%, and the B content exceeds 0.010%. And it is disadvantageous in terms of cost. Therefore, the Ti content is set to 0.20% or less, the Nb content is set to 0.20% or less, the V content is set to 0.10% or less, and the B content is set to 0.010% or less.
[0018]
Cr, Mo: Both Cr and Mo, like Mn, have the function of stabilizing austenite to promote transformation strengthening, and are effective in increasing the strength of steel sheets. Is contained. However, if the Cr content exceeds 1.0% and the Mo content exceeds 1.0%, there is a problem in the surface treatment properties of the steel sheet. Therefore, the Cr content was set to 1.0% or less, and the Mo content was set to 1.0% or less.
[0019]
Cu, Ni: Cu and Ni have a corrosion inhibitory effect, have a function of concentrating on the surface to suppress the invasion of hydrogen, and suppress delayed destruction. Therefore, one or more of them are contained as necessary. However, when the content exceeds 1.0%, the effect is saturated and the cost is disadvantageous. Therefore, both the Cu content and the Ni content were determined to be 1.0% or less.
[0020]
Ca: Ca has an effect of improving local ductility by binding to S and spheroidizing sulfides, so Ca is added as necessary. However, if the content exceeds 0.01%, the effect is saturated and the cost becomes disadvantageous. Therefore, the Ca content is set to 0.01% or less.
[0021]
The composition other than the above is Fe and inevitable impurities.
The steel having the above composition is melted by, for example, a converter, an electric furnace, a flat furnace, or the like. The steel type may be any of rimed steel, capped steel, semi-killed steel and killed steel. Further, the casting of the billet may be performed by any means of "ingot-bulking rolling" or "continuous casting".
The type of galvanized steel sheet according to the present invention is not particularly limited as long as it is a zinc-based galvanized steel sheet. And so on. Further, the plating layer may be provided on both sides of the steel sheet, or may be provided on one side.
[0022]
(C) Manufacturing Conditions In order to manufacture the “high-strength hot-dip galvanized steel sheet excellent in formability suitable as a material for a portion where corrosion resistance is important” according to the present invention, first, a steel slab having a component composition specified by the present invention is subjected to 1050. After heating to a temperature of at least ℃, start rough rolling. After finishing the rough rolling, finish the rolling as it is or after heating or maintaining the temperature of the rough bar as necessary, and finish the rolling at a finishing temperature of 740 to 1030 ° C. Thereafter, hot rolling is performed by cooling at an average cooling rate of 5 ° C./s or more and winding at 700 ° C. or less.
[0023]
Heating the billet to 1050 ° C. or higher is necessary to secure the finishing temperature. A finishing temperature of 740 ° C. or higher is a condition necessary to suppress ferrite from being coarsened with rolling at a temperature lower than the transformation point, and a finishing temperature of 1030 ° C. or lower makes the structure of the hot-rolled sheet finer. This is a condition necessary for forming sufficient ferrite after annealing of the cold rolled sheet.
It is effective to heat or maintain the temperature of the rough bar before finishing rolling to secure the finishing temperature. There is no problem even if the rough bar is joined and subjected to continuous rolling.
In hot rolling, the slab to be inserted into the heating furnace may be “a slab kept at a high temperature after casting” or “a slab left at room temperature”.
[0024]
After finishing the rolling, the material is cooled at an average cooling rate of 5 ° C./s or more to reduce the band-like structure, and is wound at 700 ° C. or less. If the winding temperature is higher than 700 ° C., a band-like structure that lowers the bendability of the product develops, which is not preferable.
[0025]
After hot rolling, if necessary, skin pass rolling for flatness correction and pickling for scale removal are performed, and preferably cold rolling at a rolling reduction of 30% or more is performed to perform annealing (continuous annealing) and Hot-dip galvanized. In the annealing, after performing a process of holding for 5 seconds or more in a temperature range of 720 to 900 ° C., cooling to 460 to 600 ° C. at a cooling rate of 2 to 30 ° C./s, and holding for 10 to 90 seconds in the temperature range. After further cooling, hot-dip galvanizing is performed, and alloying treatment is performed if necessary, and then rapidly cooled from 200 ° C. to 100 ° C. or less within 300 seconds.
[0026]
In this case, at an annealing temperature of less than 720 ° C. and a heating holding time of less than 5 seconds, austenitization is insufficient, and the amount of cementite or martensite or residual austenite in ferrite grains effective for increasing the strength is small. . On the other hand, at an annealing temperature exceeding 900 ° C., ferrite with a volume ratio of 30% or more cannot be obtained.
After the annealing, cooling is performed at an average cooling rate of 2 ° C./s or more, in order to suppress precipitation of the hard phase at the ferrite grain boundaries. In addition, the upper limit of the average cooling rate was set to 60 ° C./s so as not to cause flat defects.
In the cooling process after the annealing, it is necessary to hold the ferrite and the second phase in a temperature range of 460 to 600 ° C. for 10 to 90 seconds in order to separate the ferrite and the second phase.
[0027]
Then, following the cooling, hot-dip galvanizing is performed, and alloying is performed if necessary. However, these processing conditions are not particularly limited.
After plating, it is important to cool from 200 ° C to 100 ° C or less within 300 seconds. Thereby, precipitation of coarse cementite at the ferrite grain boundary can be suppressed. The cooling from 200 ° C. to 100 ° C. is preferably performed within 60 seconds, more preferably within 30 seconds.
[0028]
It should be noted that there is no problem if a skin pass with an elongation of 4% or less is applied for flatness correction after cooling following the plating process. Further, a film having a lubricating effect may be provided on the plating layer.
[0029]
【Example】
After smelting steel having the chemical composition shown in Table 1 in a converter, a slab was formed by continuous casting. Then, the slab was hot-rolled under the conditions shown in Table 2 to produce a hot-rolled steel sheet having a thickness of 2.6 mm.
Next, the obtained hot-rolled steel sheet was pickled, cold-rolled to a thickness of 1.2 mm, and then subjected to continuous annealing and hot-dip galvanizing under the conditions shown in Table 3.
After the hot-dip galvanizing, some materials were subjected to alloying treatment by heating to reduce the Fe content in the plating to about 10% by weight.
[0030]
[Table 1]
[0031]
[Table 2]
[0032]
[Table 3]
[0033]
With respect to the hot-dip galvanized steel sheet obtained in this manner, the base material was subjected to nital corrosion, and the metal structure was observed and specified by an optical microscope, an SEM observation, and an electron microscope.
Further, JIS No. 5 test pieces and bending test pieces were sampled in the direction perpendicular to the rolling direction, and the characteristics were examined by a tensile test.
Further, the number of ferrites containing at least one kind of cementite or martensite or retained austenite in the grains is determined by observing a region containing 100 ferrites in a given cross section of the base material plate thickness. (%).
Table 4 shows the metallographic structure and material properties investigated as described above.
[0034]
[Table 4]
[0035]
As is clear from the results shown in Table 4, the hot-dip galvanized steel sheet according to the present invention exhibited high values in both uniform elongation and local elongation.
On the other hand, in the material in which the metal structure specified in the present invention was not obtained, one or both of the uniform elongation and the local elongation were low.
The hot-dip galvanized steel sheet according to Test No. 30 having a high Si content had no problem with the properties, but the plating alloying treatment was partially insufficient, and a problem was observed with the plating quality.
[0036]
【The invention's effect】
As described above, according to the present invention, a hot-dip galvanized steel sheet having excellent uniform elongation and local elongation and suitable for reinforcing parts of automobiles requiring corrosion resistance such as rocker-inner and the like is stably provided. An industrially useful effect such as being obtained can be obtained.
[Brief description of the drawings]
FIG. 1 is a nominal stress-nominal strain curve when a tensile test is performed on a steel sheet, and is also an explanatory diagram of local elongation and uniform elongation.
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002226267A JP4000943B2 (en) | 2002-08-02 | 2002-08-02 | High-strength hot-dip galvanized steel sheet and manufacturing method thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002226267A JP4000943B2 (en) | 2002-08-02 | 2002-08-02 | High-strength hot-dip galvanized steel sheet and manufacturing method thereof |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2004068051A true JP2004068051A (en) | 2004-03-04 |
JP4000943B2 JP4000943B2 (en) | 2007-10-31 |
Family
ID=32013665
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2002226267A Expired - Fee Related JP4000943B2 (en) | 2002-08-02 | 2002-08-02 | High-strength hot-dip galvanized steel sheet and manufacturing method thereof |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP4000943B2 (en) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006307325A (en) * | 2005-03-31 | 2006-11-09 | Jfe Steel Kk | Low yield ratio type high strength alloyed hot-dip galvanized steel sheet having excellent ductility and method for producing same |
JP2006307327A (en) * | 2005-03-31 | 2006-11-09 | Jfe Steel Kk | High ductility and high strength alloyed hot-dip galvanized steel sheet having excellent surface property and brittle resistance to secondary processing and method for producing same |
JP2007211276A (en) * | 2006-02-08 | 2007-08-23 | Sumitomo Metal Ind Ltd | Plated steel sheet for hot-press use, its manufacturing method, and method for manufacturing hot press formed member |
JP2008231448A (en) * | 2007-03-16 | 2008-10-02 | Nippon Steel Corp | Steel sheet for hot dip galvannealing and hot dip galvannealed steel sheet |
JP2009179851A (en) * | 2008-01-31 | 2009-08-13 | Jfe Steel Corp | Method for producing cold-rolled steel sheet |
KR100957967B1 (en) | 2007-12-27 | 2010-05-17 | 주식회사 포스코 | High Strength Cold Rolled Steel Sheet, Galvanized Steel Sheet having Excellent Yield Strength Anisotropic Properties |
KR101076092B1 (en) | 2008-09-29 | 2011-10-21 | 현대제철 주식회사 | Hot dip galvanized hot rolled steel sheet having high strength and high elongation property and the method for manufacturing the same |
KR101149193B1 (en) * | 2009-04-27 | 2012-05-24 | 현대제철 주식회사 | Steel sheet having excellent formability and galvanizing property, and method for producing the same |
CN102719751A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | High-strength cold-rolled hot-galvanized dual-phase steel plate and manufacturing method thereof |
KR101505268B1 (en) * | 2013-03-28 | 2015-03-24 | 현대제철 주식회사 | Skin pass roll and method of manufacturing galvannealed steel sheet using the same |
JP2018502987A (en) * | 2014-12-22 | 2018-02-01 | ポスコPosco | Hot-rolled steel sheet for high-strength galvanized steel sheet with excellent surface quality and manufacturing method thereof |
WO2019132362A1 (en) * | 2017-12-26 | 2019-07-04 | 주식회사 포스코 | Cold-rolled steel sheet for flux-cored wire and method for producing same |
CN110541107A (en) * | 2018-05-28 | 2019-12-06 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum-zinc steel plate with tensile strength of 600MPa and manufacturing method thereof |
US11060157B2 (en) | 2016-03-31 | 2021-07-13 | Jfe Steel Corporation | Steel sheet, coated steel sheet, method for producing hot-rolled steel sheet, method for producing full hard cold-rolled steel sheet, method for producing steel sheet, and method for producing coated steel sheet |
CN114635090A (en) * | 2017-06-02 | 2022-06-17 | 安赛乐米塔尔公司 | Steel sheet for manufacturing press hardened part, press hardened part having a combination of high strength and collision ductility, and method for manufacturing same |
CN114875306A (en) * | 2017-06-01 | 2022-08-09 | 安赛乐米塔尔公司 | Method for producing a high-strength steel component with improved ductility and component obtained by said method |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102676918B (en) * | 2012-06-13 | 2013-07-31 | 鞍钢股份有限公司 | Hot rolled steel plate for hot-dip galvanizing pot and production method thereof |
-
2002
- 2002-08-02 JP JP2002226267A patent/JP4000943B2/en not_active Expired - Fee Related
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006307325A (en) * | 2005-03-31 | 2006-11-09 | Jfe Steel Kk | Low yield ratio type high strength alloyed hot-dip galvanized steel sheet having excellent ductility and method for producing same |
JP2006307327A (en) * | 2005-03-31 | 2006-11-09 | Jfe Steel Kk | High ductility and high strength alloyed hot-dip galvanized steel sheet having excellent surface property and brittle resistance to secondary processing and method for producing same |
JP2007211276A (en) * | 2006-02-08 | 2007-08-23 | Sumitomo Metal Ind Ltd | Plated steel sheet for hot-press use, its manufacturing method, and method for manufacturing hot press formed member |
JP2008231448A (en) * | 2007-03-16 | 2008-10-02 | Nippon Steel Corp | Steel sheet for hot dip galvannealing and hot dip galvannealed steel sheet |
KR100957967B1 (en) | 2007-12-27 | 2010-05-17 | 주식회사 포스코 | High Strength Cold Rolled Steel Sheet, Galvanized Steel Sheet having Excellent Yield Strength Anisotropic Properties |
JP2009179851A (en) * | 2008-01-31 | 2009-08-13 | Jfe Steel Corp | Method for producing cold-rolled steel sheet |
KR101076092B1 (en) | 2008-09-29 | 2011-10-21 | 현대제철 주식회사 | Hot dip galvanized hot rolled steel sheet having high strength and high elongation property and the method for manufacturing the same |
KR101149193B1 (en) * | 2009-04-27 | 2012-05-24 | 현대제철 주식회사 | Steel sheet having excellent formability and galvanizing property, and method for producing the same |
CN102719751A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | High-strength cold-rolled hot-galvanized dual-phase steel plate and manufacturing method thereof |
KR101505268B1 (en) * | 2013-03-28 | 2015-03-24 | 현대제철 주식회사 | Skin pass roll and method of manufacturing galvannealed steel sheet using the same |
JP2018502987A (en) * | 2014-12-22 | 2018-02-01 | ポスコPosco | Hot-rolled steel sheet for high-strength galvanized steel sheet with excellent surface quality and manufacturing method thereof |
US11060157B2 (en) | 2016-03-31 | 2021-07-13 | Jfe Steel Corporation | Steel sheet, coated steel sheet, method for producing hot-rolled steel sheet, method for producing full hard cold-rolled steel sheet, method for producing steel sheet, and method for producing coated steel sheet |
CN114875306A (en) * | 2017-06-01 | 2022-08-09 | 安赛乐米塔尔公司 | Method for producing a high-strength steel component with improved ductility and component obtained by said method |
CN114875306B (en) * | 2017-06-01 | 2023-04-25 | 安赛乐米塔尔公司 | Method for producing a high-strength steel component with improved ductility and component obtained by said method |
CN114635090A (en) * | 2017-06-02 | 2022-06-17 | 安赛乐米塔尔公司 | Steel sheet for manufacturing press hardened part, press hardened part having a combination of high strength and collision ductility, and method for manufacturing same |
CN114635090B (en) * | 2017-06-02 | 2023-12-22 | 安赛乐米塔尔公司 | Steel sheet for manufacturing press-hardened member, press-hardened member having a combination of high strength and impact ductility, and method for manufacturing same |
WO2019132362A1 (en) * | 2017-12-26 | 2019-07-04 | 주식회사 포스코 | Cold-rolled steel sheet for flux-cored wire and method for producing same |
CN110541107A (en) * | 2018-05-28 | 2019-12-06 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum-zinc steel plate with tensile strength of 600MPa and manufacturing method thereof |
CN110541107B (en) * | 2018-05-28 | 2021-04-06 | 上海梅山钢铁股份有限公司 | Hot-dip aluminum-zinc steel plate with tensile strength of 600MPa and manufacturing method thereof |
Also Published As
Publication number | Publication date |
---|---|
JP4000943B2 (en) | 2007-10-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4306202B2 (en) | High tensile cold-rolled steel sheet and method for producing the same | |
JP6525114B1 (en) | High strength galvanized steel sheet and method of manufacturing the same | |
EP2589677B1 (en) | High-strength hot-dip galvanized steel sheet with excellent processability and process for producing same | |
JP5578289B2 (en) | Cold-rolled steel sheet, method for producing the same, and hot stamping molded body | |
JP5651964B2 (en) | Alloyed hot-dip galvanized steel sheet excellent in ductility, hole expansibility and corrosion resistance, and method for producing the same | |
JP5540885B2 (en) | Hot-rolled hot-rolled steel sheet and manufacturing method thereof | |
JP3887235B2 (en) | High-strength steel sheet, high-strength hot-dip galvanized steel sheet, high-strength galvannealed steel sheet excellent in stretch flangeability and impact resistance, and manufacturing method thereof | |
WO2013046476A1 (en) | High strength steel plate and manufacturing method thereof | |
WO2013114850A1 (en) | Hot-dip galvanized steel sheet and production method therefor | |
JP2021502484A (en) | Cold-rolled heat-treated steel sheet and its manufacturing method | |
WO2011118421A1 (en) | Method for producing high-strength steel plate having superior deep drawing characteristics | |
JP4000943B2 (en) | High-strength hot-dip galvanized steel sheet and manufacturing method thereof | |
JP2008255442A (en) | High-tensile-strength hot-dip galvanized steel sheet and manufacturing method therefor | |
JP5305149B2 (en) | Hot-dip galvanized high-strength steel sheet with excellent formability and manufacturing method thereof | |
EP4180547A1 (en) | Hot-pressed member and manufacturing method therefor | |
CN112689684B (en) | Cold rolled and coated steel sheet and method for manufacturing the same | |
CN111448329A (en) | Cold rolled and coated steel sheet and method for manufacturing the same | |
JP2010001531A (en) | Method for manufacturing low-yield-ratio type high-strength galvannealed steel sheet | |
JP4752522B2 (en) | Manufacturing method of high strength cold-rolled steel sheet for deep drawing | |
JP2006283071A (en) | Method for producing galvannealed high strength steel sheet excellent in workability | |
JP2006283156A (en) | High-strength cold rolled steel sheet having excellent formability and weldability, high-strength hot dip galvanized steel sheet, high-strength alloyed galvannealed steel sheet, production method of high-strength cold rolled steel sheet, production method of high-strength hot dip galvanized steel sheet, and production method of high-strength alloyed galvannealed steel sheet | |
JP5659604B2 (en) | High strength steel plate and manufacturing method thereof | |
JP3473480B2 (en) | Hot-dip galvanized steel sheet excellent in strength and ductility and method for producing the same | |
JP2013076139A (en) | High-strength hot-dip galvanized steel sheet superior in plating adhesion and formability, and method for manufacturing the same | |
JP4150277B2 (en) | High strength galvannealed steel sheet excellent in press formability and method for producing the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040820 |
|
A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20060721 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20060801 |
|
A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20061002 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070123 |
|
A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070322 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070724 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070806 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100824 Year of fee payment: 3 |
|
R150 | Certificate of patent or registration of utility model |
Ref document number: 4000943 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110824 Year of fee payment: 4 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110824 Year of fee payment: 4 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120824 Year of fee payment: 5 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120824 Year of fee payment: 5 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130824 Year of fee payment: 6 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130824 Year of fee payment: 6 |
|
S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130824 Year of fee payment: 6 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
LAPS | Cancellation because of no payment of annual fees |