JP4781577B2 - High-strength hot-dip galvanized steel sheet excellent in workability and manufacturing method thereof - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、建材、家電製品、自動車などに適する加工性に優れた高強度溶融亜鉛めっき鋼板及びその製造方法に関する。
【０００２】
【従来の技術】
溶融亜鉛めっきは鋼板の防食を目的として施され、建材、家電製品、自動車など広範囲に使用されている。その製造法としては、連続ラインに於いて、脱脂洗浄後、非酸化性雰囲気にて加熱し、Ｈ2 及びＮ2 を含む還元雰囲気にて焼鈍後、めっき浴温度近傍まで冷却し、溶融亜鉛浴に浸漬後、冷却、もしくは再加熱してＦｅ−Ｚｎ合金相を生成させた後に冷却、というゼンジマー法があり、鋼板の処理に多用されている。
【０００３】
めっき前の焼鈍については、脱脂洗浄後、非酸化性雰囲気中での加熱を経ず直ちに、Ｈ2 及びＮ2 を含む還元雰囲気にて焼鈍を行う、全還元炉方式も行われる場合がある。また、鋼板を脱脂、酸洗した後、塩化アンモニウムなどを用いてフラックス処理を行って、めっき浴に浸漬、その後冷却、というフラックス法も行われている。
【０００４】
これらのめっき処理で用いられるめっき浴中には溶融亜鉛の脱酸のために少量のＡｌが添加されている。ゼンジマー法においてＺｎめっき浴は質量％で０．１％程度のＡｌを含有している。この浴中のＡｌはＦｅとの親和力がＦｅ−Ｚｎよりも強いため、鋼がめっき浴に浸漬した際、鋼表面にＦｅ−Ａｌ合金相すなわちＡｌの濃化層が生成し、Ｆｅ−Ｚｎの反応を抑制することが知られている。Ａｌの濃化層が存在するために、得られためっき層中のＡｌ含有率は通常、めっき浴中のＡｌ含有率より高くなる。
【０００５】
近年、特に自動車車体において燃費向上を目的とした車体軽量化の観点から、延性の高い高強度鋼板の需要が高まりつつある。安価な強化法として鋼中へのＳｉ添加が行われ、特に高延性高強度鋼板には１質量％以上含有する場合もある。
一方で、めっきの観点からすると鋼中のＳｉの含有率が、質量％で０．３％を超えると、通常のＡｌを含有しためっき浴を用いたゼンジマー法ではめっき濡れ性が大きく低下し、不めっきが発生するため外観品質が悪化する。この原因は、還元焼鈍時に鋼板表面にＳｉ酸化物が濃化し、Ｓｉ酸化物の溶融亜鉛に対する濡れ性が悪いためであると言われている。
【０００６】
この問題を解決する手段として、特開平３−２８３５９号公報、特開平３−６４４３７号公報等に見られるように、特定のめっきを付与することでめっき性の改善を行っているが、この方法では、溶融めっきライン焼鈍炉前段に新たにめっき設備を設けるか、もしくは、あらかじめ電気めっきラインにおいてめっき処理を行わなければならず、大幅なコストアップとなるという問題点がある。
【０００７】
【発明が解決しようとする課題】
本発明は、上記課題を解決し、不めっきが抑制され、加工性の優れた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を目的とする。
【０００８】
【課題を解決するための手段】
発明者らは、種々検討を行った結果、めっき層に特定の元素を適正濃度含有させることで、高強度鋼板の溶融亜鉛めっき濡れ性が向上することを見いだした。また、この効果は、めっき相中Ａｌ濃度を低減することで強められること、さらに、鋼のＳｉ含有率：Ｘ（質量％）、鋼のＭｎ含有率：Ｙ（質量％）、鋼のＡｌ含有率：Ｚ（質量％）、めっき層のＡｌ含有率：Ａ（質量％）、めっき層のＭｎ含有率：Ｂ（質量％）が、３−（Ｘ＋Ｙ／１０＋Ｚ／３）−１２．５×（Ａ−Ｂ）≧０を満たす鋼およびめっき組成とすることにより、極めて良好なめっきが得られることを見いだした。
【０００９】
本発明は、上記知見に基づいて完成されたもので、その要旨とするところは以下の通りである。
（１）質量％で、Ｃ：０．０００１〜０．３％、Ｓｉ：０．１〜２．５％、Ｍｎ：０．０１〜３％、Ａｌ：０．００１〜４％を含有し、残部Ｆｅ及び不可避不純物からなり、表面に、質量％で、Ａｌ：０．００１〜０．５％、Ｍｎ：０．００１〜２％、Ｆｅ：５〜２０％を含有し、残部がＺｎ及び不可避不純物からなるめっき層を有する溶融亜鉛めっき鋼板であって、鋼のＳｉ含有率：Ｘ（質量％）、鋼のＭｎ含有率：Ｙ（質量％）、鋼のＡｌ含有率：Ｚ（質量％）、めっき層のＡｌ含有率：Ａ（質量％）、めっき層のＭｎ含有率：Ｂ（質量％）が、下記（１）式を満たし、且つ、ＴＳ×Ｅｌが２２０００ＭＰａ・％以上であることを特徴とする加工性に優れた高強度溶融亜鉛めっき鋼板。
３−（Ｘ＋Ｙ／１０＋Ｚ／３）−１２．５×（Ａ−Ｂ）≧０・・・（１）
【００１１】
（２）めっき層が、質量％で、Ｓｉ：０．００１〜０．1％、Ｍｏ：０．００１〜０．１％、Ｗ：０．００１〜０．１％、Ｚｒ：０．００１〜０．１％、Ｃｓ：０．００１〜０．１％、Ｒｂ：０．００１〜０．１％、Ｋ：０．００１〜０．１％、Ａｇ：０．００１〜５％、Ｎａ：０．００１〜０．０５％、Ｃｄ：０．００１〜３％、Ｃｕ：０．００１〜３％、Ｎｉ：０．００１〜０．５％、Ｃｏ：０．００１〜１％、Ｌａ：０．００１〜０．１％、Ｔｌ：０．００１〜８％、Ｎｄ：０．００１〜０．１％、Ｙ：０．００１〜０．１％、Ｉｎ：０．００１〜５％、Ｂｅ：０．００１〜０．１％、Ｃｒ：０．００１〜０．０５％、Ｐｂ：０．００１〜１％、Ｈｆ：０．００１〜０．１％、Ｔｃ：０．００１〜０．１％、Ｔｉ：０．００１〜０．１％、Ｇｅ：０．００１〜５％、Ｔａ：０．００１〜０．１％、Ｖ：０．００１〜０．２％、Ｂ：０．００１〜０．１％、の１種または２種以上を、さらに含有することを特徴とする前記（１）に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（３）鋼が、質量％で、Ｍｏ：０．００１〜５％を、さらに含有することを特徴とする前記（１）または（２）に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（４）鋼が、質量％で、Ｃｒ：０．００１〜２５％、Ｎｉ：０．００１〜１０％、Ｗ：０．００１〜５％、Ｃｕ：０．００１〜５％、Ｃｏ：０．００１〜５％の１種または２種以上を、さらに含有することを特徴とする前記（１）乃至（３）のいずれかに記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
【００１２】
（５）鋼が、質量％で、Ｎｂ：０．００１％以上、Ｔｉ：０．００１％以上、Ｖ：０．００１％以上の１種または２種以上を合計で１％以下、さらに含有することを特徴とする前記（１）乃至（４）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（６）鋼が、質量％で、Ｂ：０．０００１〜０．１％を、さらに含有することを特徴とする前記（１）乃至（５）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（７）鋼が、質量％で、Ｚｒ：０．００１％以上、Ｈｆ：０．００１％以上、Ｔａ：０．００１％以上の１種または２種以上を合計で１％以下、さらに含有することを特徴とする前記（１）乃至（６）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（８）鋼が、質量％で、Ｙ、ＲＥＭの１種または２種以上を合計で０．０００１〜０．１％、さらに含有することを特徴とする前記（１）乃至（７）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（９）鋼が、質量％で、Ｐ：０．１％以下、Ｓ：０．１％以下を、さらに含有することを特徴とする前記（１）乃至（８）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
【００１３】
（１０）鋼のミクロ組織が、フェライト相もしくはフェライト相とベイナイト相からなり、マルテンサイト相、残留オーステナイト相の一方もしくは両方を、体積分率で合計３％以上含む複合組織であることを特徴とするとする前記（１）乃至（９）のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。
（１１）前記（１０）に記載の高強度溶融亜鉛めっき鋼板の製造において、鋳造スラブを鋳造ままもしくは一旦冷却した後に再度加熱し、熱延後巻取った熱延鋼板を酸洗後冷延し、その後、０．１×（Ａｃ3 −Ａｃ1 ）＋Ａｃ1 （℃）以上Ａｃ3＋５０（℃）以下の温度域で１０秒〜３０分焼鈍した後に、０．１〜１０℃／秒の冷却速度で５５０〜７００℃温度域に冷却し、引き続いて０．１〜１００℃／秒の冷却速度でめっき浴温度〜めっき浴温度＋１００（℃）にまで冷却した後めっき浴に浸漬し、その後合金化処理を３００〜５８０℃の温度域で行い、室温まで冷却することを特徴とする加工性に優れた高強度溶融亜鉛めっき鋼板の製造方法にある。
【００１４】
【発明の実施の形態】
以下、本発明を詳細に説明する。
発明者らは、質量％で、Ｃ ：０．０００１〜０．３％、Ｓｉ：０．１〜２．５％、Ｍｎ：０．０１〜３％、Ａｌ：０．００１〜４％を含有し、残部Ｆｅ及び不可避不純物からなる鋼板を焼鈍し、温度４５０〜４７０℃のＺｎめっき浴に３秒間浸漬を行い、さらに５００〜５５０℃で１０〜６０秒加熱を行った。その後、めっき鋼板表面の不めっき部面積を測定することでめっき性を評価し、引張り試験にて機械的性質を合わせて評価した結果を、鋼中Ｓｉ含有率：Ｘ（質量％）、鋼中Ｍｎ含有率：Ｙ（質量％）、鋼中Ａｌ含有率：Ｚ（質量％）、めっき層中Ａｌ含有率：Ａ（質量％）、めっき層中Ｍｎ含有率：Ｂ（質量％）として、
３−（Ｘ＋Ｙ／１０＋Ｚ／３）−１２．５×（Ａ−Ｂ）
の式にて整理したところ、
３−（Ｘ＋Ｙ／１０＋Ｚ／３）−１２．５×（Ａ−Ｂ）≧０
を満たす組成で、不めっきのほとんど見られない高強度溶融めっき鋼板が得られることを見出した。
【００１５】
不めっきの発生が抑制される理由の詳細については不明であるが、めっき浴中に添加されたＡｌと鋼板表面に生成したＳｉＯ2 との濡れ性が悪いため不めっきが発生すると考えられる。すなわち、Ｚｎ浴に添加したＡｌの悪影響を除去する元素を添加することで不めっきの発生を抑制することが可能となる。発明者らが鋭意検討した結果、Ｍｎを適正な濃度範囲で添加することで表記目的を達成出来ることが判明した。ＭｎはＺｎ浴中に添加しているＡｌより優先的に酸化皮膜を形成し、鋼板表面に生成しているＳｉ系の酸化皮膜との反応性を高めるものと推定される。
【００１６】
また、めっき層中に質量％で、Ｓｉ：０．００１〜０．1％、Ｍｏ：０．００１〜０．１％、Ｗ：０．００１〜０．１％、Ｚｒ：０．００１〜０．１％、Ｃｓ：０．００１〜０．１％、Ｒｂ：０．００１〜０．１％、Ｋ：０．００１〜０．１％、Ａｇ：０．００１〜５％、Ｎａ：０．００１〜０．０５％、Ｃｄ：０．００１〜３％、Ｃｕ：０．００１〜３％、Ｎｉ：０．００１〜０．５％、Ｃｏ：０．００１〜１％、Ｌａ：０．００１〜０．１％、Ｔｌ：０．００１〜８％、Ｎｄ：０．００１〜０．１％、Ｙ：０．００１〜０．１％、Ｉｎ：０．００１〜５％、Ｂｅ：０．００１〜０．１％、Ｃｒ：０．００１〜０．０５％、Ｐｂ：０．００１〜１％、Ｈｆ：０．００１〜０．１％、Ｔｃ：０．００１〜０．１％、Ｔｉ：０．００１〜０．１％、Ｇｅ：０．００１〜５％、Ｔａ：０．００１〜０．１％、Ｖ：０．００１〜０．２％、Ｂ：０．００１〜０．１％、の１種または２種以上を、さらに含有することで、不めっきが抑制されることを見出した。
【００１７】
めっき付着量については、特に制約は設けないが、耐食性の観点から片面付着量で５ｇ／ｍ2 以上であることが望ましい。本発明の溶融Ｚｎめっき鋼板上に塗装性、溶接性を改善する目的で上層めっきを施すことや、各種の処理、例えば、クロメート処理、りん酸塩処理、潤滑性向上処理、溶接性向上処理等を施しても、本発明を逸脱するものではない。
【００１８】
めっき層中Ａｌ量を０．００１〜０．５質量％の範囲としたのは、０．００１％未満では、ドロス発生が顕著で良好な外観が得られないこと、０．５％を超えてＡｌを添加すると合金化反応を著しく抑制してしまい、合金化溶融亜鉛めっき層を形成することが困難となるためである。
めっき層中Ｍｎ量を０．００１〜２質量％の範囲内としたのは、この範囲において不めっきが発生せず、良好な外観のめっきが得られるためである。Ｍｎ量が上限の２質量％を超えるとめっき浴中にてＭｎ−Ｚｎ化合物が析出し、めっき層中に取り込まれることで外観が著しく低下する。
【００１９】
めっき層中Ｓｉ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｓｉ量が上限の０．１質量％を超えるとＳｉ有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｍｏ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｍｏ量が上限の０．１質量％を超えるとＭｏを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｗ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｗ量が上限の０．１質量％を超えるとＷを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｚｒ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｚｒ量が上限の０．１質量％を超えるとＺｒを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｃｓ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｃｓ量が上限の０．１質量％を超えるとＣｓを含有するドロスの生成により、めっき外観が著しく低下する。
【００２０】
めっき層中Ｒｂ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｒｂ量が上限の０．１質量％を超えるとＲｂを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｋ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｋ量が上限の０．１質量％を超えるとＫを含有するドロスの生成により、めっき外観が著しく低下する。
【００２１】
めっき層中Ａｇ量を０．００１〜５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ａｇ量が上限の５質量％を超えるとＡｇを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｎａ量を０．００１〜０．０５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｎａ量が上限の０．０５質量％を超えるとＮａを含有するドロスの生成により、めっき外観が著しく低下する。
【００２２】
めっき層中Ｃｄ量を０．００１〜３質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｃｄ量が上限の３質量％を超えるとＣｄを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｃｕ量を０．００１〜３質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｃｕ量が上限の３質量％を超えるとＣｕを含有するドロスの生成により、めっき外観が著しく低下する。
【００２３】
めっき層中Ｎｉ量を０．００１〜０．５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｎｉ量が上限の０．５質量％を超えるとＮｉを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｃｏ量を０．００１〜１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｃｏ量が上限の１質量％を超えるとＣｏを含有するドロスの生成により、めっき外観が著しく低下する。
【００２４】
めっき層中Ｌａ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｌａ量が上限の０．１質量％を超えるとＬａを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｔｌ量を０．００１〜８質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｔｌ量が上限の８質量％を超えるとＴｌを含有するドロスの生成により、めっき外観が著しく低下する。
【００２５】
めっき層中Ｎｄ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｎｄ量が上限の０．１質量％を超えるとＮｄを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｙ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｙ量が上限の０．１質量％を超えるとＹを含有するドロスの生成により、めっき外観が著しく低下する。
【００２６】
めっき層中Ｉｎ量を０．００１〜５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｉｎ量が上限の５質量％を超えるとＩｎを含有するドロスの生成により、めっき外観が著しく低下する。
【００２７】
めっき層中Ｂｅ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｂｅ量が上限の０．１質量％を超えるとＢｅを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｃｒ量を０．００１〜０．０５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｃｒ量が上限の０．０５質量％を超えるとＣｒを含有するドロスの生成により、めっき外観が著しく低下する。
【００２８】
めっき層中Ｐｂ量を０．００１〜１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｐｂ量が上限の１質量％を超えるとＰｂを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｈｆ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｈｆ量が上限の０．１質量％を超えるとＨｆを含有するドロスの生成により、めっき外観が著しく低下する。
【００２９】
めっき層中Ｔｃ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｔｃ量が上限の０．１質量％を超えるとＴｃを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｔｉ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｔｉ量が上限の０．１質量％を超えるとＴｉを含有するドロスの生成により、めっき外観が著しく低下する。
【００３０】
めっき層中Ｇｅ量を０．００１〜５質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｇｅ量が上限の５質量％を超えるとＧｅを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｔａ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｔａ量が上限の０．１質量％を超えるとＴａを含有するドロスの生成により、めっき外観が著しく低下する。
【００３１】
めっき層中Ｖ量を０．００１〜０．２質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｖ量が上限の０．２質量％を超えるとＶを含有するドロスの生成により、めっき外観が著しく低下する。
めっき層中Ｂ量を０．００１〜０．１質量％の範囲内としたのは、この範囲において不めっきが抑制され、良好な外観のめっきが得られるためである。Ｂ量が上限の０．１質量％を超えるとＢを含有するドロスの生成により、めっき外観が著しく低下する。
【００３２】
合金化処理によってめっき層中にＦｅが取り込まれ、塗装性やスポット溶接性に優れた高強度溶融亜鉛めっき鋼板を得ることができる。Ｆｅ量が５質量％未満ではスポット溶接性が不十分となる。一方、Ｆｅ量が２０質量％を超えるとめっき層自体の密着性を損ない、加工の際めっき層が破壊・脱落し金型に付着することで、成形時の疵の原因となる。したがって、合金化処理を行う場合のめっき層中Ｆｅ量の範囲は５〜２０質量％とする。
【００３３】
次に、本発明における鋼板成分の限定理由について述べる。
Ｃ量の範囲を０．０００１〜０．３質量％の範囲内としたのは、強度を確保するためにＣ量の下限を０．０００１質量％とし、溶接性を保持可能な上限として０．３質量％とした。
Ｓｉ量の範囲を０．０１〜２．５質量％の範囲内としたのは、材質上強度を確保するためである。また、鋼中Ｓｉの上限を２．５質量％としたのは、これを超える添加は溶接性に悪影響を及ぼすためである。
【００３４】
Ｍｎ量を０．０１〜３質量％の範囲としたのは、０．０１質量％以上で強化効果が現れること、３質量％を上限としたのは、これを上回る添加は伸びに悪影響を及ぼすためである。
Ａｌ量を０．００１〜４質量％の範囲としたのは、０．００１質量％以上で強化効果が現れる。この効果は４質量％で飽和し、それを超えるとめっき性など他の特性を損ない、製造コストの観点でも不利となるためである。
【００３５】
Ｍｏは、強化に非常に有利な元素であるばかりでなく、強度延性バランスに悪影響を及ぼすパーライトや炭化物析出を効果的に抑制し、オーステナイトを残留させること、また、焼入れ性も向上させるためのマルテンサイト生成にも有利である。このため、Ｍｏは０．００１質量％以上添加することが好ましい。一方で、過剰添加は生成した残留オーステナイトの安定化を遅延させたり、フェライトを硬化させることで延性低下を引き起こすため、５質量％を上限として添加する。
さらに、本発明が対象とする鋼は、強度のさらなる向上を目的としてＣｒ、Ｎｉ、Ｗ、Ｃｕ、Ｃｏの１種または２種以上を含有できる。
Ｃｒ量を０．００１〜２５質量％の範囲としたのは、０．００１質量％以上で強化効果が現れること、２５質量％を上限としたのは、これを超える量の添加では、加工性に悪影響を及ぼすためである。
Ｎｉ量を０．００１〜１０質量％の範囲としたのは、０．００１％以上で強化効果が現れること、１０質量％を上限としたのは、これを超える量の添加では、加工性に悪影響を及ぼすためである。
【００３６】
Ｗ量を０．００１〜５質量％の範囲としたのは、０．００１質量％以上で強
化効果が現れること、５質量％を上限としたのは、これを超える量の添加では、加工性に悪影響を及ぼすためである。
Ｃｕ量を０．００１〜５質量％の範囲としたのは、０．００１質量％以上で強化効果が現れること、２５質量％を上限としたのは、これを超える量の添加では、加工性に悪影響を及ぼすためである。
【００３７】
Ｃｏ量を０．００１〜５質量％の範囲としたのは、０．００１質量％以上で強化効果が現れること、２５質量％を上限としたのは、これを超える量の添加では、加工性に悪影響を及ぼすためである。
さらに、本発明が対象とする鋼は、強度のさらなる向上を目的として強炭化物形成元素であるＮｂ，Ｔｉ，Ｖの１種または２種以上を含有できる。
【００３８】
これらの元素は、微細な炭化物、窒化物または炭窒化物を形成して、鋼板の強化のは極めて有効であるため、必要に応じて１種または２種以上を０．００１質量％以上の添加とした。一方で、延性劣化や残留オーステナイト中へのＣの濃化を阻害することから、合計添加量の上限として１質量％ととした。
Ｂもまた、必要に応じて添加できる。Ｂは、粒界の強化や鋼材の高強度化に有効ではあるが、その添加量が０．１質量％を超えるとその効果が飽和するばかりでなく、必要以上に鋼板強度を上昇させ、加工性が低下するため、上限を０．１質量％とした。
強度のさらなる向上を目的として強炭化物形成元素であるＺｒ，Ｈｆ，Ｔａの１種または２種以上を含有できる。これらの元素は、微細な炭化物、窒化物または炭窒化物を形成して、鋼板の強化には極めて有効であるため、必要に応じて１種または２種以上を０．００１質量％以上の添加とした。一方で、延性劣化や残留オーステナイト中へのＣの濃化を阻害することから、合計添加量の上限として１質量％ととした。
Ｙ、ＲＥＭの合計量を０．０００１〜０．１質量％の範囲としたのは、０．０００１質量％以上でめっきの濡れ性を改善でき、また、０．１質量％を上限としたのは、これを超える量の添加では、溶接性や鋳造時や熱延時の製造性に悪影響を及ぼすためである。
【００３９】
Ｐ量が０．１質量％を、Ｓ量が０．１質量％を、それぞれ超えると溶接性や鋳造時や熱延時の製造性に悪影響を及ぼすため、これらの値を上限として規制することが好ましいが、過度の極低化は経済的にも不利であることや、Ｐの場合は強化効果も期待できるため、Ｐ、Ｓのいずれも下限を０．０００１質量％とすることが好ましい。
また、これ以外の不純物元素としては、Ｓｎを０．０１質量％以下とすることが好ましく、この範囲であれば本発明鋼板の効果に悪影響は及ぼさない。
次に、基材鋼板の好ましいミクロ組織について述べる。
加工性を十分に確保するためには主組織をフェライト相とするのが望ましいが、高強度化を考慮するとベイナイト相を含んでも良い。また、高強度と高延性を両立させるため、残留オーステナイト相および／またはマルテンサイト相を含む複合組織とする。高強度と高延性のために、残留オーステナイト相とマルテンサイト相は、体積率で合計３％以上とした。上限は特に定めないが、体積率が合計４０％を超えると脆化傾向を示すため、４０％以下が望ましい。
【００４０】
このような組織を有する高強度溶融亜鉛めっき鋼板の製造方法について以下説明する。
熱延後冷延・焼鈍して本発明の鋼板を製造する場合には、所定の成分に調整されたスラブを鋳造ままもしくは一旦冷却した後再加熱して熱延を行い、その後酸洗し、冷延後焼鈍することで最終製品とする。この時、熱延完了温度は鋼の化学成分によって決まるＡｒ3 変態温度以上で行うのが一般的であるが、Ａｒ3 から１０℃程度低温までであれば最終的な鋼板の特性を劣化させない。また、冷却後の巻取温度は鋼の化学成分によって決まるベイナイト変態開始温度以上とすることで、冷延時の荷重を必要以上に高めることがさけられるが、冷延の全圧下率が小さい場合にはこの限りでなく、鋼のベイナイト変態温度以下で巻き取られても最終的な鋼板の特性を劣化させない。また、冷延の全圧下率は、最終板厚と冷延荷重の関係から設定されるが、４０％以上であれば最終的な鋼板の特性を劣化させない。
【００４１】
冷延後焼鈍する際に、焼鈍温度が鋼の化学成分によって決まる温度Ａｃ1 及びＡｃ3 温度（例えば「鉄鋼材料学」：Ｗ． Ｃ． Ｌｅｓｌｉｅ著、幸田成康監訳、丸善Ｐ２７３）で、表現される０．１×（Ａｃ3 −Ａｃ1 ）＋Ａｃ1 （℃）未満の場合には、焼鈍温度で得られるオーステナイト量が少ないので、最終的な鋼板中に残留オーステナイト相またはマルテンサイト相を残すことができないためにこれを焼鈍温度の下限とした。また、焼鈍温度がＡｃ3 ＋５０（℃）を超えても何ら鋼板の特性を改善することがでず製造コストの上昇をまねくために、焼鈍温度の上限をＡｃ3 ＋５０（℃）とした。この温度での焼鈍時間は鋼板の温度均一化とオーステナイトの確保のために１０秒以上が必要である。しかし、３分超では、効果が飽和するばかりでなくコストの上昇を招くのでこれを上限とした。
【００４２】
その後の一次冷却はオーステナイト相からフェライト相への変態を促して、未変態のオーステナイト相中にＣを濃化させてオーステナイトの安定化をはかるのに重要である。この冷却速度が０．１℃／秒以下にすることは、必要な生産ライン長を長くしたり、生産速度を極めて遅くするといった製造上のデメリットを生じるために、この冷却速度の下限を０．１℃／秒とした。一方、冷却速度が１０℃／秒以上の場合にはフェライト変態が十分に起こらず、最終的な鋼板中の残留オーステナイト相確保が困難となったり、マルテンサイト相などの硬質相が多量になってしまうため、これを上限とした。
【００４３】
この一次冷却が５５０℃未満まで行われると、冷却中にパーライトが生成し、オーステナイト安定化元素であるＣを浪費し、最終的に十分な量の残留オーステナイトが得られないために、これを下限とした。しかしながら、冷却が７００℃超までしか行われなかった場合にはフェライト変態の進行が十分ではないので、これを上限とした。
引き続き行われる二次冷却の急速冷却は、冷却中にパーライト変態や鉄炭化物の析出などが起こらないような冷却速度として最低０．１℃／秒以上が必要となる。但しこの冷却速度を１００℃／秒以上にすることは設備能力上困難であることから、０．１〜１００℃を冷却速度の範囲とした。
【００４４】
この二次冷却の冷却停止温度がめっき浴温度よりも低いと操業上問題となり、めっき浴温度＋１００（℃）を超えると炭化物析出が短時間で生じるため、得られる残留オーステナイトやマルテンサイトの量が確保できなくなる。このため、２次冷却の停止温度をめっき浴温度以上めっき浴温度＋１００（℃）とした。
鋼板中に残留しているオーステナイト相を室温で安定にするためには、その一部をベイナイト相へ変態させる事でオーステナイト中の炭素濃度を更に高めることが必須である。合金化処理を併せてベイナイト変態を促進するために３００〜５５０℃の温度域に１５秒から２０分保持することが望ましい。３００℃未満ではベイナイト変態が起こりにくく、５８０℃を超えると炭化物が生じて十分な残留オーステナイト相を残すことが困難となるため合金化処理温度の上限を５８０℃ととした。
【００４５】
マルテンサイト相を生成させるには、残留オーステナイト相の場合とは異なりベイナイト変態を生じさせる必要がない。一方では、炭化物やパーライト相の生成は残留オーステナイト相と同様、抑制する必要があるため、２次冷却後の十分な合金化処理を行うため４００℃〜５５０℃の温度域で合金化処理することとする。
【００４６】
【実施例】
以下、実施例によって本発明をさらに詳細に説明する。
表１に示すような組成の鋼板を、１２００℃に加熱し、Ａｒ3 変態温度以上で熱延を完了し、冷却後各鋼の化学成分で決まるベイナイト変態開始温度以上で巻き取った鋼帯を酸洗後、冷延して１．０ｍｍ厚とした。
その後、各鋼の成分（質量％）から下記式にしたがってＡｃ1 とＡｃ3 変態温度を計算により求めた。
これらのＡｃ1 およびＡｃ3 変態温度から計算される焼鈍温度に１０％Ｈ2 −Ｎ2 雰囲気中で昇温・保定したのち、０．１〜１０℃／秒の冷却速度で５５０〜７００℃温度域に冷却し、引き続いて０．１〜２０℃／秒の冷却速度でめっき浴温度にまで冷却し、浴組成を種々変化させた４６０℃の亜鉛めっき浴に３秒間浸漬することでめっきを行った。
【００４８】
また、一部の鋼板については、Ｆｅ−Ｚｎ合金化処理として、めっき後の鋼板を３００〜５８０℃の温度域で１５秒〜２０分保持し、めっき層中のＦｅ含有率が質量％で５〜２０となるよう調節した。めっき表面外観のドロス巻き込み状況の目視観察および不めっき部面積の測定によりめっき性を評価した。作製しためっきはめっき層をインヒビターを含有した５％塩酸溶液で溶解し化学分析に供し組成を求め表２に示した。
【００４９】
表１より、本発明鋼は、強度・伸びバランスに優れＴＳ×Ｅｌが２２０００ＭＰａ・％と高いことがわかる。一方、本発明の成分範囲を満たさない比較例は、いずれも強度・伸びバランスに劣りＴＳ×Ｅｌの値が１５０００ＭＰａ・％以下と低い。表２および表３より、本発明の鋼板（表中２〜５６）は、不めっき発生が少なく、外観も良好である。それに比較して本発明の範囲を逸脱する場合（表中５７〜６３）は、不めっきの発生が多いあるいは外観が不良、もしくは所定の材質を満たさない。また、表４は７および１２の製造条件と材質の関係を示した表であるが、本願発明の請求項の範囲で製造した鋼板は、ミクロ組織も上述した組織になっており強度・伸びバランスに優れている。
【００５０】
【表１】
【表２】
【表３】
【表４】
【発明の効果】
本発明の高強度溶融亜鉛めっき鋼板は不めっきの発生が抑制され外観及び加工性が良好であり、建材、家電製品、自動車車体用途等に極めて有効である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-strength hot-dip galvanized steel sheet excellent in workability suitable for building materials, home appliances, automobiles, and the like, and a method for producing the same.
[0002]
[Prior art]
Hot dip galvanizing is applied for the purpose of corrosion protection of steel sheets, and is widely used in building materials, home appliances, automobiles and the like. As a manufacturing method, after degreasing and cleaning in a continuous line, heat in a non-oxidizing atmosphere, anneal in a reducing atmosphere containing H2 and N2, cool to the plating bath temperature, and immerse in a molten zinc bath Thereafter, there is a Sendzimer method of cooling or reheating to generate an Fe—Zn alloy phase and then cooling, which is frequently used for the treatment of steel sheets.
[0003]
As for annealing before plating, an all-reducing furnace method in which annealing is performed in a reducing atmosphere containing H2 and N2 immediately after degreasing and without heating in a non-oxidizing atmosphere may be performed. In addition, a flux method is also performed in which a steel sheet is degreased and pickled, and then flux treatment is performed using ammonium chloride and the like, soaking in a plating bath, and then cooling.
[0004]
A small amount of Al is added to the plating bath used in these plating processes for deoxidation of molten zinc. In the Sendzimer method, the Zn plating bath contains about 0.1% Al by mass%. Since Al in this bath has a stronger affinity for Fe than Fe-Zn, when steel is immersed in the plating bath, an Fe-Al alloy phase, that is, an Al concentrated layer, is formed on the steel surface. It is known to suppress the reaction. Due to the presence of the Al concentrated layer, the Al content in the obtained plating layer is usually higher than the Al content in the plating bath.
[0005]
In recent years, the demand for high-strength steel sheets having high ductility has been increasing from the viewpoint of reducing the weight of a vehicle body for the purpose of improving fuel consumption especially in the automobile body. As an inexpensive strengthening method, Si is added to the steel, and the high ductility and high strength steel sheet may contain 1% by mass or more.
On the other hand, from the viewpoint of plating, when the Si content in the steel exceeds 0.3% by mass, plating wettability is greatly reduced in the Sendzimer method using a plating bath containing ordinary Al, Appearance quality deteriorates because non-plating occurs. It is said that this is because Si oxide is concentrated on the surface of the steel sheet during reduction annealing, and the wettability of Si oxide to molten zinc is poor.
[0006]
As a means for solving this problem, as shown in JP-A-3-28359, JP-A-3-64437 and the like, the plating property is improved by applying specific plating. Then, it is necessary to provide a new plating facility in front of the hot dipping line annealing furnace or to perform a plating process in the electroplating line in advance, resulting in a significant increase in cost.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems, and to provide a high-strength hot-dip galvanized steel sheet that is excellent in workability and in which non-plating is suppressed and a method for producing the same.
[0008]
[Means for Solving the Problems]
As a result of various studies, the inventors have found that the wettability of a high-strength steel sheet is improved by adding a specific element to the plating layer at an appropriate concentration. Moreover, this effect can be strengthened by reducing the Al concentration in the plating phase. Furthermore, the Si content of steel: X (mass%), the Mn content of steel: Y (mass%), and the Al content of steel. Rate: Z (mass%), Al content of plating layer: A (mass%), Mn content of plating layer: B (mass%) is 3- (X + Y / 10 + Z / 3) -12.5 × ( It has been found that extremely good plating can be obtained by using a steel and plating composition satisfying A−B) ≧ 0.
[0009]
The present invention has been completed based on the above findings, and the gist thereof is as follows.
(1) By mass%, C: 0.0001 to 0.3%, Si: 0.1 to 2.5%, Mn: 0.01 to 3%, Al: 0.001 to 4%, The balance is composed of Fe and inevitable impurities, and on the surface, by mass, Al: 0.001 to 0.5%, Mn: 0.001 to 2%, Fe: 5 to 20%, the balance being Zn and inevitable A hot-dip galvanized steel sheet having a plating layer made of impurities, comprising: Si content of steel: X (mass%), Mn content of steel: Y (mass%), Al content of steel: Z (mass%) The Al content of the plating layer: A (mass%) and the Mn content of the plating layer: B (mass%) satisfy the following formula (1).And TS × El is 22000 MPa ·% or more.A high-strength hot-dip galvanized steel sheet with excellent workability.
3- (X + Y / 10 + Z / 3) -12.5 × (A−B) ≧ 0 (1)
[0011]
(2) Plating layer is mass%, Si: 0.001 to 0.1%, Mo: 0.001 to 0.1%, W: 0.001 to 0.1%, Zr: 0.001 0.1%, Cs: 0.001 to 0.1%, Rb: 0.001 to 0.1%, K: 0.001 to 0.1%, Ag: 0.001 to 5%, Na: 0 0.001 to 0.05%, Cd: 0.001 to 3%, Cu: 0.001 to 3%, Ni: 0.001 to 0.5%, Co: 0.001 to 1%, La: 0.00. 001 to 0.1%, Tl: 0.001 to 8%, Nd: 0.001 to 0.1%, Y: 0.001 to 0.1%, In: 0.001 to 5%, Be: 0 0.001 to 0.1%, Cr: 0.001 to 0.05%, Pb: 0.001 to 1%, Hf: 0.001 to 0.1%, Tc: 0.001 to 0.1%, Ti: 0.001 to 0.1% , Ge: 0.001-5%, Ta: 0.001-0.1%, V: 0.001-0.2%, B: 0.001-0.1%, one or more Further containing (1))High-strength hot-dip galvanized steel sheet with excellent workability as described.
(3The steel (1) is characterized by further containing Mo: 0.001 to 5% by mass.Or (2)High-strength hot-dip galvanized steel sheet with excellent workability as described in 1.
(4) Steel is mass%, Cr: 0.001-25%, Ni: 0.001-10%, W: 0.001-5%, Cu: 0.001-5%, Co: 0.001- (1) to (1) characterized by further containing 5% of one kind or two or more kinds3) High-strength hot-dip galvanized steel sheet with excellent workability.
[0012]
(5) The steel further contains 1% or less in total of one or more of Nb: 0.001% or more, Ti: 0.001% or more, V: 0.001% or more in mass%. Features (1) to (4The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
(6The steel (1) to (1), wherein the steel further contains B: 0.0001 to 0.1% by mass%.5The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
(7) The steel further contains 1% or less in total of one or more of Zr: 0.001% or more, Hf: 0.001% or more, Ta: 0.001% or more in mass%. Features (1) to (6The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
(8(1) to (1), wherein the steel further contains 0.0001 to 0.1% in total of one or more of Y and REM in mass%.7The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
(9) The steel further contains, by mass%, P: 0.1% or less and S: 0.1% or less (1) to (8The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
[0013]
(10) It is characterized in that the microstructure of the steel is a composite structure comprising a ferrite phase or a ferrite phase and a bainite phase and containing one or both of a martensite phase and a retained austenite phase in a total volume of 3% or more. (1) to (9The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of the above.
(11) (10In the production of the high-strength hot-dip galvanized steel sheet described in (1), the cast slab is cast as it is or once cooled and then heated again, and the hot-rolled steel sheet wound after hot rolling is pickled and cold-rolled, and then 0.1% X (Ac3 -Ac1) + Ac1 (° C.) After annealing in a temperature range of not less than Ac3 + 50 (° C.) for 10 seconds to 30 minutes, it is cooled to a temperature range of 550 to 700 ° C. at a cooling rate of 0.1 to 10 ° C./second. Subsequently, after cooling from a plating bath temperature to a plating bath temperature +100 (° C.) at a cooling rate of 0.1 to 100 ° C./second, the substrate is immersed in a plating bath, and then alloying treatment is performed in a temperature range of 300 to 580 ° C. It is in the manufacturing method of the high intensity | strength hot-dip galvanized steel plate excellent in workability characterized by performing and cooling to room temperature.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The inventors include, in mass%, C: 0.0001 to 0.3%, Si: 0.1 to 2.5%, Mn: 0.01 to 3%, Al: 0.001 to 4%. Then, the steel sheet composed of the remaining Fe and inevitable impurities was annealed, immersed in a Zn plating bath at a temperature of 450 to 470 ° C. for 3 seconds, and further heated at 500 to 550 ° C. for 10 to 60 seconds. Thereafter, the plating property was evaluated by measuring the area of the unplated portion on the surface of the plated steel sheet, and the result of evaluating the mechanical properties in combination with the tensile test was determined as follows: Si content in steel: X (mass%), Mn content: Y (mass%), Al content in steel: Z (mass%), Al content in plating layer: A (mass%), Mn content in plating layer: B (mass%),
3- (X + Y / 10 + Z / 3) -12.5 × (A−B)
When arranged by the formula of
3- (X + Y / 10 + Z / 3) -12.5 × (A−B) ≧ 0
It was found that a high-strength hot-dip galvanized steel sheet having a composition satisfying the above condition and having almost no plating was obtained.
[0015]
Although the details of the reason why the occurrence of non-plating is suppressed are unknown, it is considered that non-plating occurs due to poor wettability between Al added in the plating bath and SiO2 formed on the steel plate surface. That is, it is possible to suppress the occurrence of non-plating by adding an element that removes the adverse effect of Al added to the Zn bath. As a result of intensive studies by the inventors, it was found that the notation purpose can be achieved by adding Mn in an appropriate concentration range. It is presumed that Mn forms an oxide film preferentially over Al added in the Zn bath and enhances the reactivity with the Si-based oxide film generated on the steel sheet surface.
[0016]
Further, in the plating layer in mass%, Si: 0.001 to 0.1%, Mo: 0.001 to 0.1%, W: 0.001 to 0.1%, Zr: 0.001 to 0 0.1%, Cs: 0.001 to 0.1%, Rb: 0.001 to 0.1%, K: 0.001 to 0.1%, Ag: 0.001 to 5%, Na: 0.0. 001 to 0.05%, Cd: 0.001 to 3%, Cu: 0.001 to 3%, Ni: 0.001 to 0.5%, Co: 0.001 to 1%, La: 0.001 -0.1%, Tl: 0.001-8%, Nd: 0.001-0.1%, Y: 0.001-0.1%, In: 0.001-5%, Be: 0.0. 001-0.1%, Cr: 0.001-0.05%, Pb: 0.001-1%, Hf: 0.001-0.1%, Tc: 0.001-0.1%, Ti : 0.001 to 0.1% , Ge: 0.001-5%, Ta: 0.001-0.1%, V: 0.001-0.2%, B: 0.001-0.1%, one or more Furthermore, it discovered that non-plating was suppressed by containing.
[0017]
The plating adhesion amount is not particularly limited, but is preferably 5 g / m 2 or more in terms of single-sided adhesion from the viewpoint of corrosion resistance. For the purpose of improving the paintability and weldability on the hot-dip Zn plated steel sheet of the present invention, various treatments such as chromate treatment, phosphate treatment, lubricity improvement treatment, weldability improvement treatment, etc. However, the present invention does not depart from the present invention.
[0018]
The reason why the amount of Al in the plating layer is in the range of 0.001 to 0.5 mass% is that if it is less than 0.001%, dross generation is remarkable and a good appearance cannot be obtained, exceeding 0.5% When Al is added, the alloying reaction is remarkably suppressed, and it becomes difficult to form an alloyed hot-dip galvanized layer.
The reason why the amount of Mn in the plating layer is set in the range of 0.001 to 2 mass% is that no plating is generated in this range and plating with a good appearance can be obtained. When the amount of Mn exceeds 2 mass% of an upper limit, a Mn-Zn compound will precipitate in a plating bath and it will take in in a plating layer, and an external appearance will fall remarkably.
[0019]
The reason why the Si amount in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Si exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross having Si.
The reason why the amount of Mo in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Mo exceeds the upper limit of 0.1% by mass, the appearance of plating is significantly deteriorated due to generation of dross containing Mo.
The reason why the W amount in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of W exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to the generation of dross containing W.
The reason why the amount of Zr in the plating layer is in the range of 0.001 to 0.1 mass% is that non-plating is suppressed in this range, and plating with a good appearance can be obtained. When the amount of Zr exceeds the upper limit of 0.1% by mass, the appearance of the plating is remarkably deteriorated due to generation of dross containing Zr.
The reason why the amount of Cs in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Cs exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to the generation of dross containing Cs.
[0020]
The reason why the amount of Rb in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Rb exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to the generation of dross containing Rb.
The reason why the amount of K in the plating layer is in the range of 0.001 to 0.1 mass% is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of K exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing K.
[0021]
The reason why the amount of Ag in the plating layer is in the range of 0.001 to 5% by mass is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of Ag exceeds the upper limit of 5% by mass, the appearance of plating is significantly deteriorated due to the generation of dross containing Ag.
The reason why the amount of Na in the plating layer is within the range of 0.001 to 0.05 mass% is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Na exceeds the upper limit of 0.05% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Na.
[0022]
The reason why the amount of Cd in the plating layer is in the range of 0.001 to 3% by mass is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of Cd exceeds the upper limit of 3% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Cd.
The reason why the amount of Cu in the plating layer is within the range of 0.001 to 3% by mass is that non-plating is suppressed within this range and plating with a good appearance is obtained. When the amount of Cu exceeds the upper limit of 3% by mass, the appearance of plating is remarkably deteriorated due to the generation of dross containing Cu.
[0023]
The reason why the amount of Ni in the plating layer is within the range of 0.001 to 0.5% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Ni exceeds the upper limit of 0.5% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Ni.
The reason why the amount of Co in the plating layer is within the range of 0.001 to 1% by mass is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of Co exceeds the upper limit of 1% by mass, the appearance of plating is significantly deteriorated due to the generation of dross containing Co.
[0024]
The reason why the amount of La in the plating layer is set in the range of 0.001 to 0.1% by mass is that non-plating is suppressed in this range and plating with a good appearance can be obtained. When the amount of La exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing La.
The reason why the amount of Tl in the plating layer is in the range of 0.001 to 8% by mass is that non-plating is suppressed in this range and plating with a good appearance can be obtained. When the amount of Tl exceeds the upper limit of 8% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Tl.
[0025]
The reason why the amount of Nd in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Nd exceeds the upper limit of 0.1% by mass, the appearance of plating is significantly deteriorated due to generation of dross containing Nd.
The reason why the amount of Y in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Y exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to the generation of dross containing Y.
[0026]
The reason why the amount of In in the plating layer is in the range of 0.001 to 5% by mass is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of In exceeds the upper limit of 5% by mass, the appearance of plating is significantly deteriorated due to generation of dross containing In.
[0027]
The reason why the amount of Be in the plating layer is in the range of 0.001 to 0.1 mass% is that non-plating is suppressed in this range, and plating with a good appearance can be obtained. When the amount of Be exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Be.
The reason why the Cr content in the plating layer is within the range of 0.001 to 0.05% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Cr exceeds the upper limit of 0.05% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Cr.
[0028]
The reason why the amount of Pb in the plating layer is within the range of 0.001 to 1% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Pb exceeds the upper limit of 1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Pb.
The reason why the amount of Hf in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Hf exceeds the upper limit of 0.1% by mass, the appearance of plating is significantly deteriorated due to generation of dross containing Hf.
[0029]
The reason why the amount of Tc in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range, and plating with a good appearance can be obtained. When the amount of Tc exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Tc.
The reason why the amount of Ti in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Ti exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Ti.
[0030]
The reason why the amount of Ge in the plating layer is within the range of 0.001 to 5% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of Ge exceeds the upper limit of 5% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing Ge.
The reason why the amount of Ta in the plating layer is in the range of 0.001 to 0.1 mass% is that non-plating is suppressed in this range and plating with a good appearance is obtained. When the amount of Ta exceeds the upper limit of 0.1% by mass, the appearance of plating is significantly deteriorated due to the generation of dross containing Ta.
[0031]
The reason why the amount of V in the plating layer is within the range of 0.001 to 0.2% by mass is that non-plating is suppressed in this range and plating with a good appearance can be obtained. When the amount of V exceeds the upper limit of 0.2% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing V.
The reason why the amount of B in the plating layer is within the range of 0.001 to 0.1% by mass is that non-plating is suppressed within this range and plating with a good appearance can be obtained. When the amount of B exceeds the upper limit of 0.1% by mass, the appearance of plating is remarkably deteriorated due to generation of dross containing B.
[0032]
Fe is taken into the plating layer by the alloying treatment, and a high-strength hot-dip galvanized steel sheet excellent in paintability and spot weldability can be obtained. If the amount of Fe is less than 5% by mass, spot weldability is insufficient. On the other hand, if the amount of Fe exceeds 20% by mass, the adhesion of the plating layer itself is impaired, and the plating layer breaks and drops during processing and adheres to the mold, thereby causing defects during molding. Therefore, the range of the amount of Fe in the plating layer when alloying is performed is 5 to 20% by mass..
[0033]
Next, the reasons for limiting the steel plate components in the present invention will be described.
The range of the C amount is within the range of 0.0001 to 0.3% by mass because the lower limit of the C amount is 0.0001% by mass in order to ensure strength, and the upper limit for maintaining weldability is 0.00. The content was 3% by mass.
The reason why the Si amount is within the range of 0.01 to 2.5% by mass is to ensure strength in terms of material. The reason why the upper limit of Si in the steel is set to 2.5% by mass is that addition exceeding this value adversely affects weldability.
[0034]
The reason why the Mn amount is in the range of 0.01 to 3% by mass is that a strengthening effect appears at 0.01% by mass or more, and the upper limit of 3% by mass has an adverse effect on elongation. Because.
The reason why the Al amount is in the range of 0.001 to 4 mass% is that the strengthening effect appears at 0.001 mass% or more. This effect is saturated at 4% by mass, and beyond that, other characteristics such as plating properties are impaired, and this is disadvantageous from the viewpoint of manufacturing cost.
[0035]
Mo is not only a very advantageous element for strengthening, but also effectively suppresses the precipitation of pearlite and carbides that adversely affect the strength-ductility balance, leaving austenite, and also improving the hardenability. It is also advantageous for site generation. For this reason, it is preferable to add Mo 0.001 mass% or more. On the other hand, excessive addition delays stabilization of the produced retained austenite or causes ductile deterioration by hardening the ferrite, so 5 mass% is added as the upper limit.
Furthermore, the steel targeted by the present invention can contain one or more of Cr, Ni, W, Cu, Co for the purpose of further improving the strength.
The Cr content in the range of 0.001 to 25% by mass means that a strengthening effect appears at 0.001% by mass or more, and the upper limit is 25% by mass. This is to adversely affect
The amount of Ni in the range of 0.001 to 10% by mass is that the strengthening effect appears at 0.001% or more, and the upper limit of 10% by mass is the workability when the amount exceeds this. This is to have an adverse effect.
[0036]
The amount of W is in the range of 0.001 to 5% by mass and is strong at 0.001% by mass or more.
The reason why the effect of crystallization appears is that the upper limit of 5% by mass is that if the amount exceeds this, the workability is adversely affected.
The amount of Cu in the range of 0.001 to 5% by mass is that the strengthening effect appears at 0.001% by mass or more, and the upper limit of 25% by mass is the workability when the amount exceeds this. This is to adversely affect
[0037]
The Co content in the range of 0.001 to 5 mass% is that the strengthening effect appears at 0.001 mass% or more, and the upper limit of 25 mass% is the workability when the amount exceeds this amount. This is to adversely affect
Furthermore, the steel targeted by the present invention can contain one or more of Nb, Ti, and V, which are strong carbide forming elements, for the purpose of further improving the strength.
[0038]
These elements form fine carbides, nitrides or carbonitrides, and are extremely effective in strengthening steel sheets. If necessary, one or more elements are added in an amount of 0.001% by mass or more. It was. On the other hand, since it inhibits ductility deterioration and concentration of C in retained austenite, the upper limit of the total addition amount is set to 1% by mass.
B can also be added as needed. B is effective for strengthening grain boundaries and increasing the strength of steel, but when the amount of addition exceeds 0.1% by mass, the effect is not only saturated, but the strength of the steel sheet is increased more than necessary. The upper limit was made 0.1% by mass because the properties deteriorated.
For the purpose of further improving the strength, one or more of Zr, Hf, Ta, which are strong carbide forming elements, can be contained. These elements form fine carbides, nitrides, or carbonitrides, and are extremely effective for strengthening steel sheets. Therefore, one or more elements are added in an amount of 0.001% by mass or more as necessary. It was. On the other hand, since it inhibits ductility deterioration and concentration of C in retained austenite, the upper limit of the total addition amount is set to 1% by mass.
The total amount of Y and REM is in the range of 0.0001 to 0.1% by mass because the wettability of plating can be improved by 0.0001% by mass or more, and the upper limit is 0.1% by mass. This is because addition of an amount exceeding this adversely affects weldability and manufacturability during casting and hot rolling.
[0039]
If the amount of P exceeds 0.1% by mass and the amount of S exceeds 0.1% by mass, the weldability and the manufacturability during casting and hot rolling are adversely affected. However, excessively low is economically disadvantageous, and in the case of P, a strengthening effect can be expected. Therefore, it is preferable that the lower limit of both P and S is 0.0001% by mass.
Moreover, as an impurity element other than this, it is preferable to make Sn into 0.01 mass% or less, and if it is this range, it will not have a bad influence on the effect of this invention steel plate.
Next, a preferable microstructure of the base steel sheet will be described.
In order to sufficiently secure the workability, it is desirable that the main structure is a ferrite phase, but a bainite phase may be included in consideration of increasing the strength. Further, in order to achieve both high strength and high ductility, a composite structure including a retained austenite phase and / or a martensite phase is formed. For high strength and high ductility, the residual austenite phase and martensite phase were made 3% or more in total by volume. The upper limit is not particularly defined, but 40% or less is desirable because the embrittlement tendency is exhibited when the volume ratio exceeds 40% in total.
[0040]
A method for producing a high-strength hot-dip galvanized steel sheet having such a structure will be described below.
When producing the steel sheet of the present invention by cold rolling and annealing after hot rolling, the slab adjusted to a predetermined component is cast or once cooled and then reheated and hot rolled, and then pickled. Finished by annealing after cold rolling. At this time, the hot rolling completion temperature is generally higher than the Ar3 transformation temperature determined by the chemical composition of the steel, but if the temperature is lower than Ar3 by about 10 ° C, the final steel sheet characteristics will not be deteriorated. In addition, the coiling temperature after cooling is higher than the bainite transformation start temperature determined by the chemical composition of the steel, so that the load during cold rolling can be increased more than necessary, but when the total rolling reduction of cold rolling is small Is not limited to this, and even if the steel sheet is wound at a temperature lower than the bainite transformation temperature of the steel, the properties of the final steel sheet are not deteriorated. Further, the total rolling reduction ratio of the cold rolling is set based on the relationship between the final sheet thickness and the cold rolling load, but if it is 40% or more, the final steel sheet characteristics are not deteriorated.
[0041]
When annealing after cold rolling, the annealing temperature is expressed by the temperatures Ac1 and Ac3 determined by the chemical composition of the steel (for example, “Steel Material Science” written by W. C. Leslie, translated by Naruyasu Koda, Maruzen P273). When the temperature is less than 1 × (Ac3−Ac1) + Ac1 (° C.), the amount of austenite obtained at the annealing temperature is so small that the retained austenite phase or martensite phase cannot be left in the final steel sheet. Was the lower limit of the annealing temperature. Further, even if the annealing temperature exceeded Ac3 +50 (° C), the upper limit of the annealing temperature was set to Ac3 +50 (° C) in order to improve the manufacturing cost without improving the properties of the steel sheet. The annealing time at this temperature requires 10 seconds or more to make the temperature of the steel plate uniform and to secure austenite. However, if it exceeds 3 minutes, the effect is not only saturated but also the cost is increased, so this is set as the upper limit.
[0042]
Subsequent primary cooling is important for promoting the transformation from the austenite phase to the ferrite phase and concentrating C in the untransformed austenite phase to stabilize the austenite. Setting the cooling rate to 0.1 ° C./second or less causes manufacturing disadvantages such as lengthening the necessary production line length or extremely slowing the production rate. The temperature was 1 ° C./second. On the other hand, when the cooling rate is 10 ° C./second or more, ferrite transformation does not occur sufficiently, and it becomes difficult to secure the retained austenite phase in the final steel sheet, or the hard phase such as martensite phase becomes large. Therefore, this is the upper limit.
[0043]
If this primary cooling is performed to less than 550 ° C., pearlite is generated during cooling, and C, which is an austenite stabilizing element, is wasted, and finally a sufficient amount of retained austenite cannot be obtained. It was. However, when the cooling is performed only to over 700 ° C., the ferrite transformation does not proceed sufficiently, so this was set as the upper limit.
The subsequent rapid cooling of the secondary cooling requires a cooling rate of at least 0.1 ° C./second or more so as not to cause pearlite transformation or precipitation of iron carbide during cooling. However, since it is difficult to improve the cooling rate to 100 ° C./second or more in terms of equipment capacity, 0.1 to 100 ° C. is set as the cooling rate range.
[0044]
If the cooling stop temperature of this secondary cooling is lower than the plating bath temperature, it becomes an operational problem, and if it exceeds the plating bath temperature +100 (° C.), carbide precipitation occurs in a short time, so the amount of residual austenite and martensite obtained is It cannot be secured. For this reason, the secondary cooling stop temperature is set to the plating bath temperature + 100 (° C.) or more.
In order to stabilize the austenite phase remaining in the steel sheet at room temperature, it is essential to further increase the carbon concentration in the austenite by transforming a part thereof into the bainite phase. In order to promote the bainite transformation together with the alloying treatment, it is desirable to maintain the temperature range of 300 to 550 ° C. for 15 seconds to 20 minutes. If it is less than 300 ° C., bainite transformation is difficult to occur, and if it exceeds 580 ° C., carbides are formed and it is difficult to leave a sufficient residual austenite phase, so the upper limit of the alloying treatment temperature is set to 580 ° C.
[0045]
Unlike the retained austenite phase, it is not necessary to cause the bainite transformation to produce the martensite phase. On the other hand, it is necessary to suppress the formation of carbides and pearlite phases in the same manner as the retained austenite phase. And
[0046]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
A steel strip having a composition as shown in Table 1 is heated to 1200 ° C., and hot rolling is completed at or above the Ar3 transformation temperature, and after cooling, the steel strip wound up at or above the bainite transformation start temperature determined by the chemical composition of each steel is acidified. After washing, it was cold rolled to a thickness of 1.0 mm.
Thereafter, the Ac1 and Ac3 transformation temperatures were calculated from the components (mass%) of each steel according to the following formula.
After heating and holding in an atmosphere of 10% H2-N2 to the annealing temperature calculated from these Ac1 and Ac3 transformation temperatures, it is cooled to a temperature range of 550-700 ° C at a cooling rate of 0.1-10 ° C / second. Subsequently, the plating was performed by cooling to a plating bath temperature at a cooling rate of 0.1 to 20 ° C./second, and immersing in a 460 ° C. zinc plating bath with various changes in the bath composition for 3 seconds.
[0048]
Moreover, about some steel plates, as a Fe-Zn alloying process, the steel plate after plating is hold | maintained for 15 seconds-20 minutes in the temperature range of 300-580 degreeC, and the Fe content rate in a plating layer is 5 by mass%. Adjusted to ~ 20. The plating property was evaluated by visual observation of the dross entrainment state of the plating surface appearance and measurement of the area of the non-plated part. The prepared plating was dissolved in a 5% hydrochloric acid solution containing an inhibitor and subjected to chemical analysis, and the composition was determined and shown in Table 2.
[0049]
Table 1 shows that the steel of the present invention is excellent in strength / elongation balance and TS × El is as high as 22000 MPa ·%. On the other hand, all of the comparative examples not satisfying the component range of the present invention are inferior in strength / elongation balance and have a low value of TS × El of 15000 MPa ·% or less. From Table 2 and Table 3, the steel plate of the present invention (in the table2-56) have less unplating and good appearance. If it deviates from the scope of the present invention as compared to that (from 5763) Has a large amount of non-plating or has a poor appearance or does not satisfy a predetermined material. Table 4 shows the relationship between the manufacturing conditions of 7 and 12 and the material, but the steel sheet manufactured in the scope of the claims of the present invention has the microstructure described above, and the strength / elongation balance. Is excellent.
[0050]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
【The invention's effect】
The high-strength hot-dip galvanized steel sheet of the present invention is excellent in appearance and workability due to suppression of non-plating, and is extremely effective for building materials, home appliances, automobile body applications, and the like.
Claims (11)
Ｃ ：０．０００１〜０．３％、
Ｓｉ：０．１〜２．５％、
Ｍｎ：０．０１〜３％、
Ａｌ：０．００１〜４％を含有し、残部Ｆｅ及び不可避不純物からなり、表面に、質量 ％で、
Ａｌ：０．００１〜０．５％、
Ｍｎ：０．００１〜２％、
Ｆｅ：５〜２０％を含有し、残部がＺｎ及び不可避不純物からなるめっき層を有する溶 融亜鉛めっき鋼板であって、
鋼のＳｉ含有率：Ｘ（質量％）、鋼のＭｎ含有率：Ｙ（質量％）、鋼のＡｌ含有率：Ｚ （質量％）、めっき層のＡｌ含有率：Ａ（質量％）、めっき層のＭｎ含有率：Ｂ（質量 ％）が、下記（１）式を満たし、且つ、ＴＳ×Ｅｌが２２０００ＭＰａ・％以上である ことを特徴とする加工性に優れた高強度溶融亜鉛めっき鋼板。
３−（Ｘ＋Ｙ／１０＋Ｚ／３）−１２．５×（Ａ−Ｂ）≧０・・・（１）% By mass
C: 0.0001 to 0.3%,
Si: 0.1 to 2.5%
Mn: 0.01 to 3%
Al: 0.001-4% contained, consisting of the remainder Fe and inevitable impurities, on the surface, in mass%,
Al: 0.001 to 0.5%,
Mn: 0.001-2%,
Fe: a hot dip galvanized steel sheet having a plating layer containing 5 to 20%, the balance being Zn and inevitable impurities,
Steel Si content: X (mass%), steel Mn content: Y (mass%), steel Al content: Z (mass%), plating layer Al content: A (mass%), plating Mn content of the layer: B (% by mass) is, meets the following expression (1), and a high-strength galvanized steel sheet having excellent workability, wherein the TS × El is 22000MPa ·% or more .
3- (X + Y / 10 + Z / 3) -12.5 × (A−B) ≧ 0 (1)
Ｓｉ：０．００１〜０．1％、
Ｍｏ：０．００１〜０．１％、
Ｗ：０．００１〜０．１％、
Ｚｒ：０．００１〜０．１％、
Ｃｓ：０．００１〜０．１％、
Ｒｂ：０．００１〜０．１％、
Ｋ ：０．００１〜０．１％、
Ａｇ：０．００１〜５％、
Ｎａ：０．００１〜０．０５％、
Ｃｄ：０．００１〜３％、
Ｃｕ：０．００１〜３％、
Ｎｉ：０．００１〜０．５％、
Ｃｏ：０．００１〜１％、
Ｌａ：０．００１〜０．１％、
Ｔｌ：０．００１〜８％、
Ｎｄ：０．００１〜０．１％、
Ｙ ：０．００１〜０．１％、
Ｉｎ：０．００１〜５％、
Ｂｅ：０．００１〜０．１％、
Ｃｒ：０．００１〜０．０５％、
Ｐｂ：０．００１〜１％、
Ｈｆ：０．００１〜０．１％、
Ｔｃ：０．００１〜０．１％、
Ｔｉ：０．００１〜０．１％、
Ｇｅ：０．００１〜５％、
Ｔａ：０．００１〜０．１％、
Ｖ ：０．００１〜０．２％、
Ｂ ：０．００１〜０．１％の１種または２種以上を、さらに含有することを特徴とす る請求項１に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。The plating layer is mass%,
Si: 0.001 to 0.1%
Mo: 0.001 to 0.1%,
W: 0.001 to 0.1%,
Zr: 0.001 to 0.1%,
Cs: 0.001 to 0.1%,
Rb: 0.001 to 0.1%,
K: 0.001 to 0.1%,
Ag: 0.001 to 5%,
Na: 0.001 to 0.05%,
Cd: 0.001 to 3%
Cu: 0.001 to 3%,
Ni: 0.001 to 0.5%,
Co: 0.001-1%,
La: 0.001 to 0.1%,
Tl: 0.001-8%
Nd: 0.001 to 0.1%,
Y: 0.001 to 0.1%
In: 0.001 to 5%,
Be: 0.001 to 0.1%,
Cr: 0.001 to 0.05%,
Pb: 0.001 to 1%,
Hf: 0.001 to 0.1%,
Tc: 0.001 to 0.1%,
Ti: 0.001 to 0.1%,
Ge: 0.001 to 5%,
Ta: 0.001 to 0.1%,
V: 0.001 to 0.2%,
B: 0.001 to 0.1% of one or more high-strength galvanized steel sheet having excellent formability according to claim 1 you characterized by further comprising.
Ｍｏ：０．００１〜５％を、さらに含有することを特徴とする請求項１または２に記載 の加工性に優れた高強度溶融亜鉛めっき鋼板。Steel is mass%
Mo: 0.001 to 5%, even high-strength galvanized steel sheet having excellent formability according to claim 1 or 2, characterized in that it contains.
Ｃｒ：０．００１〜２５％、
Ｎｉ：０．００１〜１０％、
Ｗ ：０．００１〜５％、
Ｃｕ：０．００１〜５％、
Ｃｏ：０．００１〜５％の１種または２種以上を、さらに含有することを特徴とする請 求項１乃至３のいずれか１項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。Steel is mass%
Cr: 0.001 to 25%,
Ni: 0.001 to 10%,
W: 0.001 to 5%,
Cu: 0.001 to 5%,
The high-strength hot-dip galvanized steel sheet excellent in workability according to any one of claims 1 to 3 , further comprising one or more of Co: 0.001 to 5%. .
Ｎｂ：０．００１％以上、
Ｔｉ：０．００１％以上、
Ｖ ：０．００１％以上の１種または２種以上を合計で１％以下、さらに含有すること を特徴とする請求項１乃至４のいずれか１項に記載の加工性に優れた高強度溶融亜鉛め っき鋼板。Steel is mass%
Nb: 0.001% or more,
Ti: 0.001% or more,
V: High-strength melt excellent in workability according to any one of claims 1 to 4 , further comprising 1% or less in total of 1 type or 2 types or more of 0.001% or more Galvanized steel sheet.
Ｚｒ：０．００１％以上、
Ｈｆ：０．００１％以上、
Ｔａ：０．００１％以上の１種または２種以上を合計で１％以下、さらに含有すること を特徴とする請求項１乃至６のいずれか１項に記載の加工性に優れた高強度溶融亜鉛め っき鋼板。Steel is mass%
Zr: 0.001% or more,
Hf: 0.001% or more,
The high-strength melt excellent in workability according to any one of claims 1 to 6 , further comprising 1% or less of Ta: 0.001% or more in total of 1% or less Galvanized steel sheet.
Ｙ、ＲＥＭの１種または２種以上を合計で０．０００１〜０．１％、さらに含有するこ とを特徴とする請求項１乃至７のいずれか１項に記載の加工性に優れた高強度溶融亜鉛 めっき鋼板。Steel is mass%
The high workability according to any one of claims 1 to 7 , further comprising 0.0001 to 0.1% in total of one or more of Y and REM. Strength hot dip galvanized steel sheet.
Ｐ ：０．１％以下、
Ｓ ：０．１％以下を、さらに含有することを特徴とする請求項１乃至８のいずれか１ 項に記載の加工性に優れた高強度溶融亜鉛めっき鋼板。Steel is mass%
P: 0.1% or less,
The high strength hot-dip galvanized steel sheet with excellent workability according to any one of claims 1 to 8 , further comprising S: 0.1% or less.
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| JP5250939B2 (en) * | 2005-03-31 | 2013-07-31 | Ｊｆｅスチール株式会社 | Method for producing galvannealed steel sheet |
| CN103131984A (en) * | 2011-11-29 | 2013-06-05 | 贵州铝厂 | High-performance low zinc hot dipping aluminium alloy plating material |
| CN103131982B (en) * | 2011-11-29 | 2015-03-11 | 贵州科学院 | Multi-combination degenerative low-zinc hot-dipped aluminum alloy coating material |
| JP5852690B2 (en) | 2013-04-26 | 2016-02-03 | 株式会社神戸製鋼所 | Alloyed hot-dip galvanized steel sheet for hot stamping |
| CN103627984A (en) * | 2013-11-11 | 2014-03-12 | 马鞍山市恒毅机械制造有限公司 | Wear-resistant alloy steel material for sand maker hammerhead and preparation method thereof |
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| CN105624555A (en) * | 2016-01-20 | 2016-06-01 | 宋晓玲 | High-strength and high-toughness alloy steel |
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| JP2798520B2 (en) * | 1991-03-27 | 1998-09-17 | 日新製鋼株式会社 | Alloyed hot-dip galvanized steel sheet excellent in workability and method for producing the same |
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