公开(公告)号：US20130022490A1

公开(公告)日：2013-01-24

申请号：US13634614

申请日：2011-03-22

申请人： Hideo Hata ,  Toshio Murakami ,  Yukihiro Utsumi

发明人： Hideo Hata ,  Toshio Murakami ,  Yukihiro Utsumi

IPC分类号： C22C38/06 ,  C22C38/04 ,  C22C38/38 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/02 ,  C22C38/08

CPC分类号： C21D8/0226 ,  C21D1/20 ,  C21D8/0447 ,  C21D8/0463 ,  C21D8/0473 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38

摘要： Disclosed is a high-strength steel plate with excellent warm workability that has a component composition comprising, in mass %, 0.05 to 0.4% C, 0.5 to 3% Si+Al, 0.5 to 3% Mn, no more than 0.15% P (not including 0%), and no more than 0.02% S (including 0%), with the remainder comprising iron and impurities, and a composition that includes a total of 45 to 80% martensite and/or bainitic ferrite in terms of the area ratio relative to the entire composition, 5 to 40% polygonal ferrite in terms of the area ratio relative to the entire composition, and 5 to 20% retained austenite in terms of the area ratio relative to the entire composition, wherein the C concentration (CγR) within said residual austenite is in the range of 0.6 mass % to less than 1.0 mass %, and that furthermore may include bainite. In the high-strength steel plate, TRIP effects are achieved to the fullest extent in warm working, and increased ductility over prior steel plates is reliably achieved.

摘要翻译： 公开了一种具有优异的温加工性的高强度钢板，其具有以质量％计含有0.05〜0.4％的C，0.5〜3％的Si + Al，0.5〜3％的Mn，0.15％以下的P（ 不包括0％）和不超过0.02％的S（包括0％），剩余部分包括铁和杂质，以及包括总共45-80％的马氏体和/或贝氏体铁素体的组合物的面积 相对于整个组合物的比率，相对于组合物的面积比为5〜40％的多边形铁素体，相对于组合物的面积比为5〜20％的残留奥氏体，其中C浓度 ）在0.6质量％以下且小于1.0质量％的范围内，并且还可以包括贝氏体。 在高强度钢板中，TRIP效果在温暖加工中达到最大程度，并且可靠地实现了比现有钢板更高的延展性。

公开(公告)号：US08932414B2

公开(公告)日：2015-01-13

申请号：US13634614

申请日：2011-03-22

申请人： Hideo Hata ,  Toshio Murakami ,  Yukihiro Utsumi

发明人： Hideo Hata ,  Toshio Murakami ,  Yukihiro Utsumi

IPC分类号： C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D8/02 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C21D8/04 ,  C21D1/20

CPC分类号： C21D8/0226 ,  C21D1/20 ,  C21D8/0447 ,  C21D8/0463 ,  C21D8/0473 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38

摘要： Disclosed is a high-strength steel plate with excellent warm workability that has a component composition comprising, in mass %, 0.05 to 0.4% C, 0.5 to 3% Si+Al, 0.5 to 3% Mn, no more than 0.15% P (not including 0%), and no more than 0.02% S (including 0%), with the remainder comprising iron and impurities, and a composition that includes a total of 45 to 80% martensite and/or bainitic ferrite in terms of the area ratio relative to the entire composition, 5 to 40% polygonal ferrite in terms of the area ratio relative to the entire composition, and 5 to 20% retained austenite in terms of the area ratio relative to the entire composition, wherein the C concentration (CγR) within said residual austenite is in the range of 0.6 mass % to less than 1.0 mass %, and that furthermore may include bainite. In the high-strength steel plate, TRIP effects are achieved to the fullest extent in warm working, and increased ductility over prior steel plates is reliably achieved.

摘要翻译： 公开了一种具有优异的温加工性的高强度钢板，其具有以质量％计含有0.05〜0.4％的C，0.5〜3％的Si + Al，0.5〜3％的Mn，0.15％以下的P（ 不包括0％）和不超过0.02％的S（包括0％），剩余部分包括铁和杂质，以及包括总共45-80％的马氏体和/或贝氏体铁素体的组合物的面积 相对于整个组合物的比率，相对于组合物的面积比为5〜40％的多边形铁素体，相对于组合物的面积比为5〜20％的残留奥氏体，其中C浓度 ）在0.6质量％以下且小于1.0质量％的范围内，并且还可以包括贝氏体。 在高强度钢板中，TRIP效果在温暖加工中达到最大程度，并且可靠地实现了比现有钢板更高的延展性。

公开(公告)号：US09657381B2

公开(公告)日：2017-05-23

申请号：US14238599

申请日：2012-08-15

申请人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Naoki Mizuta ,  Tatsuya Asai

发明人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Naoki Mizuta ,  Tatsuya Asai

IPC分类号： C22C38/00 ,  C22C38/38 ,  C21D8/02 ,  B21D22/20 ,  C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

CPC分类号： C22C38/38 ,  B21D22/208 ,  C21D8/0226 ,  C21D8/0236 ,  C21D9/46 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

摘要： This high-strength steel plate has a component composition including, by mass %, C: 0.02-0.3%, Si: 1-3%, Mn: 1.8-3%, P: 0.1% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.002-0.03%, the rest consisting of iron and impurities. Said steel plate has a microstructure including, in terms of area ratio relative to the entire microstructure, each of the following phases: bainitic ferrite: 50-85%; retained γ: 3% or greater; martensite+the aforementioned retained γ: 10-45%; and ferrite: 5-40%. The C concentration (CγR) in the aforementioned retained austenite is 0.3-1.2 mass %, part or all of the N in the aforementioned component composition is solid solution N, and the amount of said solid solution N is 30-100 ppm.

公开(公告)号：US09194032B2

公开(公告)日：2015-11-24

申请号：US14001819

申请日：2012-02-27

申请人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

发明人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

IPC分类号： C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/58 ,  C21D8/04 ,  C21D9/48 ,  C22C38/00 ,  C22C38/42 ,  C22C38/44 ,  C22C38/54 ,  C21D6/00

CPC分类号： C22C38/58 ,  C21D6/005 ,  C21D8/04 ,  C21D8/0426 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/34 ,  C22C38/38 ,  C22C38/42 ,  C22C38/44 ,  C22C38/54

摘要： This high-strength steel sheet has a component composition containing, in mass %, 0.02 to 0.3% C, 1 to 3% Si, 1.8 to 3% Mn, 0.1% or less P, 0.01% or less S, 0.001 to 0.1% Al, and 0.002 to 0.03% N, the remainder being iron and impurities. The high-strength steel sheet has a structure containing, in terms of area ratio relative to the entire structure, each of the following phases: 50 to 85% bainitic ferrite; 3% or more retained austenite (γ); 10 to 45% martensite and the aforementioned retained austenite (γ); and 5 to 40% ferrite. The ratio between the Mn concentration (MnγR) in the retained austenite (γ) and the average Mn concentration (Mnav) in the entire structure is 1.2 or more (MnγR/ Mnav) based on the Mn concentration distribution obtained by means of EPMA line analysis. As a consequence, the high-strength steel sheet exhibits strength of 980 MPa or more and exerts excellent deep drawability.

摘要翻译： 该高强度钢板具有以质量％计含有C：0.02〜0.3％，Si：1〜3％，Mn：1.8〜3％，P：0.1％以下，S：0.01％以下，S：0.001〜0.1％ Al，0.002〜0.03％N，其余为铁和杂质。 高强度钢板的结构，相对于整个结构体的面积比，包含以下各相：50〜85％的贝氏体铁素体， 3％以上残余奥氏体（γ）; 10〜45％马氏体和上述残留奥氏体（γ）; 和5〜40％的铁素体。 基于通过EPMA线分析获得的Mn浓度分布，残留奥氏体（γ）中的Mn浓度（MnγR）与整个结构中的平均Mn浓度（Mnav）之比为1.2以上（MnγR/ Mnav） 。 因此，高强度钢板的强度为980MPa以上，并且具有优异的深冲性。

公开(公告)号：US20100252147A1

公开(公告)日：2010-10-07

申请号：US12742323

申请日：2008-11-20

申请人： Toshio Murakami ,  Hideo Hata ,  Akira Ibano ,  Kenji Saito

发明人： Toshio Murakami ,  Hideo Hata ,  Akira Ibano ,  Kenji Saito

IPC分类号： C22C38/22 ,  C22C38/00 ,  C22C38/04 ,  C22C38/16 ,  C22C38/18 ,  C22C38/08

CPC分类号： C22C38/02 ,  C21D8/0405 ,  C21D8/0447 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/003 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06

摘要： The invention provides a high-strength cold-rolled steel sheet which is improved in elongation and stretch-flangeability and exhibits more excellent formability. The high-strength cold-rolled steel sheet has a composition which contains by mass C: 0.03 to 0.30%, Si: 0.1 to 3.0%, Mn: 0.1 to 5.0%, P: 0.1% or below, S: 0.005% or below, N: 0.01% or below, and Al: 0.01 to 1.00% with the balance consisting of iron and unavoidable impurities. The high-strength cold-rolled steel sheet has a structure which comprises at least 40% (up to 100% inclusive) in terms of area fraction of tempered martensite having a hardness of 300 to 380 Hv and the balance ferrite. The cementite particles in the tempered martensite take such dispersion that 10 or more cementite particles having equivalent-circle diameters of 0.02 to less than 0.1 μm are present per one μm2 of the tempered martensite and three or fewer cementite particles having equivalent-circle diameters of 0.1 μm or above are present per one μm2 of the tempered martensite.

摘要翻译： 本发明提供了一种提高伸长率和拉伸凸缘性的高强度冷轧钢板，并且具有更优异的成形性。 高强度冷轧钢板的组成为C：0.03〜0.30％，Si：0.1〜3.0％，Mn：0.1〜5.0％，P：0.1％以下，S：0.005％以下 ，N：0.01％以下，Al：0.01〜1.00％，余量由铁和不可避免的杂质构成。 高强度冷轧钢板具有以硬度为300〜380Hv的回火马氏体的面积率和平衡铁素体为至少40％（含有100％以上）的结构。 回火马氏体中的渗碳体颗粒采用这样的分散体，每1μm回火马氏体和三个或更少个当量圆直径为0.1的渗碳体颗粒存在10个或更多个当量圆直径为0.02至小于0.1μm的渗碳体颗粒 每1μm2的回火马氏体存在1μm以上。

公开(公告)号：US08840738B2

公开(公告)日：2014-09-23

申请号：US13258823

申请日：2010-04-02

申请人： Toshio Murakami ,  Akira Ibano ,  Hideo Hata ,  Kenji Saito

发明人： Toshio Murakami ,  Akira Ibano ,  Hideo Hata ,  Kenji Saito

IPC分类号： C21D11/00 ,  C22C1/00 ,  C21D9/48 ,  C21D9/46 ,  C21D8/04 ,  C22C38/00 ,  C22C38/04 ,  C22C38/22 ,  C22C38/44

CPC分类号： C21D8/0405 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/003 ,  C21D2211/005 ,  C21D2211/008 ,  C22C1/002

摘要： A cold-rolled steel sheet of the present invention which has a composition containing, in terms of % by mass, C: 0.05-0.30%, Si: 3.0% or less (including 0%), Mn: 0.1-5.0%, P: 0.1% or less (including 0%), S: 0.010% or less (including 0%), and Al: 0.001-0.10%, and remainder being mainly iron, and which has a structure comprising, in terms of area ratio, 10-80% ferrite, less than 5% (including 0%) of the sum of retained austenite and martensite, and a hard phase as the remainder. The steel sheet gives a KAM value frequency distribution curve in which the relationship between the proportion of frequency having a KAM value ≦0.4, XKAM≦0.4°, and the area ratio of ferrite, Vα satisfies XKAM≦0.4°/Vα≧0.8 and the proportion of frequency having a KAM value in the range of 0.6-0.8, XKAM=0.6-0.8° is 10-20%. In the hard phase adjoining the ferrite, cementite, grains having an equivalent circle diameter of 0.1 μm or larger exist so that three or less such cementite grains are dispersed per μm2 of the hard phase. The steel sheet has improved balance between elongation and stretch flangeability and has better formability.

摘要翻译： 本发明的冷轧钢板，其组成为以质量％计含有C：0.05〜0.30％，Si：3.0％以下（含0％），Mn：0.1-5.0％，P ：0.1％以下（包括0％），S：0.010％以下（包括0％），Al：0.001-0.10％，余量主要为铁，其结构为面积比， 10-80％的铁素体，小于残留奥氏体和马氏体之和的5％（包括0％），剩余部分为硬质相。 钢板给出KAM值频率分布曲线，其中具有KAM值＆lt; lE; 0.4，XKAM＆nlE; 0.4°的频率的比例与铁素体的面积比Vα之间的关系满足XKAM＆nlE; 0.4°/Vα≥0.8，以及 KAM值在0.6-0.8，XKAM = 0.6-0.8°范围内的频率比例为10-20％。 在与铁素体相邻的硬相中，存在具有当量圆直径为0.1μm以上的渗碳体，每μm2硬相分散3个以下的渗碳体粒子。 钢板具有提高伸长率和拉伸凸缘性之间的平衡，并且具有更好的成形性。

公开(公告)号：US08679265B2

公开(公告)日：2014-03-25

申请号：US12742323

申请日：2008-11-20

申请人： Toshio Murakami ,  Hideo Hata ,  Akira Ibano ,  Kenji Saito

发明人： Toshio Murakami ,  Hideo Hata ,  Akira Ibano ,  Kenji Saito

IPC分类号： C22C38/00 ,  C22C38/22 ,  C22C38/08

CPC分类号： C22C38/02 ,  C21D8/0405 ,  C21D8/0447 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/003 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06

摘要： The invention provides a high-strength cold-rolled steel sheet which is improved in elongation and stretch-flangeability and exhibits more excellent formability. The high-strength cold-rolled steel sheet has a composition which contains by mass C: 0.03 to 0.30%, Si: 0.1 to 3.0%, Mn: 0.1 to 5.0%, P: 0.1% or below, S: 0.005% or below, N: 0.01% or below, and Al: 0.01 to 1.00% with the balance consisting of iron and unavoidable impurities. The high-strength cold-rolled steel sheet has a structure which comprises at least 40% (up to 100% inclusive) in terms of area fraction of tempered martensite having a hardness of 300 to 380 Hv and the balance ferrite. The cementite particles in the tempered martensite take such dispersion that 10 or more cementite particles having equivalent-circle diameters of 0.02 to less than 0.1 μm are present per one μm2 of the tempered martensite and three or fewer cementite particles having equivalent-circle diameters of 0.1 μm or above are present per one μm2 of the tempered martensite.

摘要翻译： 本发明提供了一种提高伸长率和拉伸凸缘性的高强度冷轧钢板，并且具有更优异的成形性。 高强度冷轧钢板的组成为C：0.03〜0.30％，Si：0.1〜3.0％，Mn：0.1〜5.0％，P：0.1％以下，S：0.005％以下 ，N：0.01％以下，Al：0.01〜1.00％，余量由铁和不可避免的杂质构成。 高强度冷轧钢板具有以硬度为300〜380Hv的回火马氏体的面积率和平衡铁素体为至少40％（含有100％以上）的结构。 回火马氏体中的渗碳体颗粒采用这样的分散体，每1μm回火马氏体和三个或更少个当量圆直径为0.1的渗碳体颗粒存在10个或更多个当量圆直径为0.02至小于0.1μm的渗碳体颗粒 每1μm2的回火马氏体存在1μm以上。

公开(公告)号：US20130330226A1

公开(公告)日：2013-12-12

申请号：US14001819

申请日：2012-02-27

申请人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

发明人： Toshio Murakami ,  Elijah Kakiuchi ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

IPC分类号： C22C38/58 ,  C22C38/04 ,  C22C38/42 ,  C22C38/00 ,  C22C38/54 ,  C22C38/44 ,  C22C38/06 ,  C22C38/02

CPC分类号： C22C38/58 ,  C21D6/005 ,  C21D8/04 ,  C21D8/0426 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/34 ,  C22C38/38 ,  C22C38/42 ,  C22C38/44 ,  C22C38/54

摘要： This high-strength steel sheet has a component composition containing, in mass %, 0.02 to 0.3% C, 1 to 3% Si, 1.8 to 3% Mn, 0.1% or less P, 0.01% or less S, 0.001 to 0.1% Al, and 0.002 to 0.03% N, the remainder being iron and impurities. The high-strength steel sheet has a structure containing, in terms of area ratio relative to the entire structure, each of the following phases: 50 to 85% bainitic ferrite; 3% or more retained austenite (γ); 10 to 45% martensite and the aforementioned retained austenite (γ); and 5 to 40% ferrite. The ratio between the Mn concentration (MnγR) in the retained austenite (γ) and the average Mn concentration (Mnav) in the entire structure is 1.2 or more (MnγR/ Mnav) based on the Mn concentration distribution obtained by means of EPMA line analysis. As a consequence, the high-strength steel sheet exhibits strength of 980 MPa or more and exerts excellent deep drawability.

摘要翻译： 该高强度钢板具有以质量％计含有C：0.02〜0.3％，Si：1〜3％，Mn：1.8〜3％，P：0.1％以下，S：0.01％以下，S：0.001〜0.1％ Al，0.002〜0.03％N，其余为铁和杂质。 高强度钢板的结构，相对于整个结构体的面积比，包含以下各相：50〜85％的贝氏体铁素体， 3％以上残余奥氏体（γ）; 10〜45％马氏体和上述残留奥氏体（γ）; 和5〜40％的铁素体。 基于通过EPMA线分析获得的Mn浓度分布，残留奥氏体（γ）中的Mn浓度（MngammaR）与整个结构中的平均Mn浓度（Mnav）之比为1.2以上（MngammaR / Mnav） 。 因此，高强度钢板的强度为980MPa以上，并且具有优异的深冲性。

公开(公告)号：US20120009434A1

公开(公告)日：2012-01-12

申请号：US13257639

申请日：2009-10-01

申请人： Hideo Hata ,  Toshio Murakami ,  Akira Ibano ,  Fumio Yuse ,  Junichiro Kinugasa

发明人： Hideo Hata ,  Toshio Murakami ,  Akira Ibano ,  Fumio Yuse ,  Junichiro Kinugasa

IPC分类号： B21C1/00

CPC分类号： C21D9/46 ,  C21D6/008 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  Y10T428/12229

摘要： Disclosed is a high-strength cold-rolled steel sheet which has improved stretch-flange formability while keeping excellent hydrogen embrittlement resistance. The cold-rolled steel sheet comprises 0.03 to 0.30% by mass of C, 3.0% by mass or less (including 0% by mass) of Si, more than 0.1% by mass and not more than 2.8% by mass of Mn, 0.1% by mass or less of P, 0.005% by mass or less of S, 0.01% by mass or less of N, and 0.01 to 0.50% by mass of Al. The cold-rolled steel sheet additionally comprises V in an amount of 0.001 to 1.00% by mass or one or more elements selected from Nb, Ti and Zr in the total amount of 0.01% by mass or more, with the remainder being made up by iron and unavoidable impurities, wherein the contents of one or more elements selected from Nb, Ti and Zr fulfils the requirement represented by the following formula: [% C]−[% Nb]/92.9×12−[% Ti]/47.9×12−[% Zr]/91.2×12>0.03. In the cold-rolled steel sheet, the area ratio of tempered martensite is 50% or more (including 100%), and ferrite makes up the remainder. In the cold-rolled steel sheet, the distribution of precipitates in the tempered martensite is as follows: the number of precipitates each having a circle-equivalent diameter of 1 to 10 nm is 20 particles or more per 1 μm2 of the tempered martensite and the number of precipitates each containing V or at least one element selected from Nb, Ti and Zr and each having a circle-equivalent diameter of 20 nm or more is 10 particles or less per 1 μm2 of the tempered martensite.

摘要翻译： 公开了一种在保持优异的耐氢脆性的同时具有改进的拉伸凸缘成形性的高强度冷轧钢板。 该冷轧钢板包含C：0.03〜0.30质量％，Si：3.0质量％以下（含有0质量％）的Si，0.1质量％以上且2.8质量％以下的Mn，0.1 以质量％以下的P，0.005质量％以下的S，0.01质量％以下的N和0.01〜0.50质量％的Al。 冷轧钢板另外包含0.001〜1.00质量％的V或者选自Nb，Ti和Zr中的一种以上的元素，总量为0.01质量％以上，余量由 铁和不可避免的杂质，其中选自Nb，Ti和Zr中的一种或多种元素的含量满足下式所示的要求：[％C] - [％Nb] /92.9×12- [％Ti] /47.9× 12- [％Zr] /91.2×12> 0.03。 在冷轧钢板中，回火马氏体的面积比为50％以上（包括100％），铁素体构成剩余部分。 在冷轧钢板中，回火马氏体中析出物的分布如下：圆形当量直径为1〜10nm的析出物的个数为每1μm2回火马氏体为20个以上， 每个含有V的析出物数量或选自Nb，Ti和Zr中的至少一种元素，每个圆当量直径为20nm以上的析出物的数量为每1μm2的回火马氏体为10个以下。

公开(公告)号：US10544489B2

公开(公告)日：2020-01-28

申请号：US13988382

申请日：2011-11-16

申请人： Elijah Kakiuchi ,  Toshio Murakami ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

发明人： Elijah Kakiuchi ,  Toshio Murakami ,  Hideo Hata ,  Tatsuya Asai ,  Naoki Mizuta

IPC分类号： C22C38/02 ,  C22C38/38 ,  C22C38/00 ,  C22C38/04 ,  C22C38/06 ,  B21D11/22 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

摘要： A high-strength steel sheet has a chemical composition including 0.05% to 0.3% of C, 1% to 3% of Si, 0.5% to 3% of Mn, 0% to 0.1% of P, 0.001% to 0.1% of Al, and 0.002% to 0.03% of N, in mass percent; further includes iron and impurities; and has a structure including 50% to 90% of bainitic ferrite, 5% to 20% of retained austenite (γR), a total of 10% to 50% of martensite and the retained austenite, and 0% to 40% of polygonal ferrite, in area percent based on the entire structure. The retained austenite has a carbon content (CγR) of 0.5% to 1.2% by mass, an average equivalent circle diameter of 0.2 to 2 μm, and an average aspect ratio (maximum diameter/minimum diameter) of less than 3.0. The high-strength steel sheet excels both in elongation and deep drawability while having a strength of 980 MPa or more.