公开(公告)号：US09139885B2

公开(公告)日：2015-09-22

申请号：US13822746

申请日：2011-09-16

申请人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Naoki Yoshinaga ,  Chisato Wakabayashi ,  Noriyuki Suzuki

发明人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Naoki Yoshinaga ,  Chisato Wakabayashi ,  Noriyuki Suzuki

IPC分类号： C21D8/02 ,  C22C38/40 ,  C25D5/10 ,  B32B15/00 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/38 ,  C23C2/06 ,  C23C2/40 ,  C22C38/04 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/34 ,  C22C38/58 ,  C23C2/02 ,  C23C2/28 ,  C25D3/22 ,  C25D5/36 ,  C25D5/50 ,  C25D3/56

CPC分类号： C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D9/46 ,  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 ,  C22C38/40 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C25D3/22 ,  C25D3/565 ,  C25D5/36 ,  C25D5/50

摘要： This high-strength steel sheet includes by mass percentage: 0.05 to 0.4% of C; 0.1 to 2.5% of Si; 1.0 to 3.5% of Mn; 0.001 to 0.03% of P; 0.0001 to 0.01% of S; 0.001 to 2.5% of Al; 0.0001 to 0.01% of N; 0.0001 to 0.008% of O; and a remainder composed of iron and inevitable impurities, wherein a steel sheet structure contains by volume fraction 10 to 50% of a ferrite phase, 10 to 50% of a tempered martensite phase, and a remaining hard phase, wherein a 98% hardness is 1.5 or more times as high as a 2% hardness in a range from ⅛ to ⅜ of a thickness of the steel sheet, wherein a kurtosis K* of the hardness distribution between the 2% hardness and the 98% hardness is −1.2 to −0.4, and wherein an average crystal grain size in the steel sheet structure is 10 μm or less.

摘要翻译： 该高强度钢板以质量百分比计：C：0.05〜0.4％ 0.1〜2.5％的Si; 1.0〜3.5％的Mn; 0.001〜0.03％P; 0.0001〜0.01％的S; 0.001〜2.5％的Al; 0.0001〜0.01％N; 0.0001〜0.008％的O; 余量由铁和不可避免的杂质组成，其中钢板结构体积体积分数为铁素体相10-50％，回火马氏体相为10-50％，剩余硬质相为98％ 在钢板厚度的⅛至⅛范围内的2％硬度的1.5倍以上，2％硬度与98％硬度之间的硬度分布的峰度K *为-1.2〜 0.4，其中，钢板结构体的平均结晶粒径为10μm以下。

公开(公告)号：US20130167980A1

公开(公告)日：2013-07-04

申请号：US13822746

申请日：2011-09-16

申请人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Naoki Yoshinaga ,  Chisato Wakabayashi ,  Noriyuki Suzuki

发明人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Naoki Yoshinaga ,  Chisato Wakabayashi ,  Noriyuki Suzuki

IPC分类号： C21D8/02 ,  C22C38/40 ,  C22C38/38 ,  C22C38/34 ,  C22C38/16 ,  C22C38/00 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/58 ,  C22C38/14

CPC分类号： C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D9/46 ,  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 ,  C22C38/40 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C25D3/22 ,  C25D3/565 ,  C25D5/36 ,  C25D5/50

摘要： This high-strength steel sheet includes by mass percentage: 0.05 to 0.4% of C; 0.1 to 2.5% of Si; 1.0 to 3.5% of Mn; 0.001 to 0.03% of P; 0.0001 to 0.01% of S; 0.001 to 2.5% of Al; 0.0001 to 0.01% of N; 0.0001 to 0.008% of O; and a remainder composed of iron and inevitable impurities, wherein a steel sheet structure contains by volume fraction 10 to 50% of a ferrite phase, 10 to 50% of a tempered martensite phase, and a remaining hard phase, wherein a 98% hardness is 1.5 or more times as high as a 2% hardness in a range from ⅛ to ⅜ of a thickness of the steel sheet, wherein a kurtosis K* of the hardness distribution between the 2% hardness and the 98% hardness is −1.2 to −0.4, and wherein an average crystal grain size in the steel sheet structure is 10 μm or less.

摘要翻译： 该高强度钢板以质量百分比计：C：0.05〜0.4％ 0.1〜2.5％的Si; 1.0〜3.5％的Mn; 0.001〜0.03％P; 0.0001〜0.01％的S; 0.001〜2.5％的Al; 0.0001〜0.01％N; 0.0001〜0.008％的O; 余量由铁和不可避免的杂质组成，其中钢板结构体积体积分数为铁素体相10-50％，回火马氏体相为10-50％，剩余硬质相为98％ 在钢板厚度的1/8至3/8的范围内的2％硬度的1.5倍或更多倍，其中2％硬度和98％硬度之间的硬度分布的峰度K *为 -1.2〜-0.4，钢板结构体的平均结晶粒径为10μm以下。

公开(公告)号：US10023947B2

公开(公告)日：2018-07-17

申请号：US13508779

申请日：2010-11-30

申请人： Masafumi Azuma ,  Noriyuki Suzuki ,  Naoki Maruyama ,  Akinobu Murasato ,  Yasuharu Sakuma ,  Hiroyuki Kawata ,  Chisato Wakabayashi

发明人： Masafumi Azuma ,  Noriyuki Suzuki ,  Naoki Maruyama ,  Akinobu Murasato ,  Yasuharu Sakuma ,  Hiroyuki Kawata ,  Chisato Wakabayashi

IPC分类号： C21D8/00 ,  C22C38/04 ,  C22C38/02 ,  C23C2/06 ,  C21D9/46 ,  C22C38/00 ,  C22C38/06 ,  C23C2/28 ,  C25D5/36 ,  C23C2/40

摘要： High strength steel plate with an ultimate tensile strength of 900 MPa or more which is excellent in hydrogen embrittlement resistance characterized in that, in the structure of the steel plate, (a) by volume fraction, ferrite is present in 10 to 50%, bainitic ferrite and/or bainite in 10 to 60%, and tempered martensite in 10 to 50%, and (b) iron-based carbides which contain Si or Si and Al in 0.1% or more are present in 4×108 (particles/mm3) or more.

公开(公告)号：US20120222781A1

公开(公告)日：2012-09-06

申请号：US13508779

申请日：2010-11-30

申请人： Masafumi Azuma ,  Noriyuki Suzuki ,  Naoki Maruyama ,  Akinobu Murasato ,  Yasuharu Sakuma ,  Hiroyuki Kawata ,  Chisato Wakabayashi

发明人： Masafumi Azuma ,  Noriyuki Suzuki ,  Naoki Maruyama ,  Akinobu Murasato ,  Yasuharu Sakuma ,  Hiroyuki Kawata ,  Chisato Wakabayashi

IPC分类号： C21D8/00 ,  C22C38/04 ,  C22C38/02 ,  C22C38/16 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/00 ,  C22C38/06

CPC分类号： C23C2/06 ,  C21D9/46 ,  C21D2211/002 ,  C21D2211/004 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C23C2/28 ,  C23C2/40 ,  C25D5/36

摘要： High strength steel plate with an ultimate tensile strength of 900 MPa or more which is excellent in hydrogen embrittlement resistance characterized in that, in the structure of the steel plate, (a) by volume fraction, ferrite is present in 10 to 50%, bainitic ferrite and/or bainite in 10 to 60%, and tempered martensite in 10 to 50%, and (b) iron-based carbides which contain Si or Si and Al in 0.1% or more are present in 4×108 (particles/mm3) or more.

摘要翻译： 具有900MPa以上的极限拉伸强度的高强度钢板，其耐氢脆性优异，其特征在于，在钢板的结构中，（a）以体积分数计，铁素体的含量为10〜50％，贝氏体 铁素体和/或贝氏体为10〜60％，回火马氏体为10〜50％，（b）含有Si或Si和Al为0.1％以上的铁基碳化物存在于4×10 8（粒子/ mm 3 ） 或者更多。

公开(公告)号：US10351937B2

公开(公告)日：2019-07-16

申请号：US14235414

申请日：2012-07-27

申请人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Akinobu Minami ,  Hajime Hasegawa ,  Chisato Wakabayashi ,  Tsuyoshi Oki

发明人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Akinobu Minami ,  Hajime Hasegawa ,  Chisato Wakabayashi ,  Tsuyoshi Oki

IPC分类号： C22C38/38 ,  C22C38/34 ,  C22C38/28 ,  C22C38/22 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C25D5/48 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C21D8/02 ,  C25D5/36 ,  C22C18/00 ,  C22C18/04 ,  B32B15/01 ,  C25D7/06

摘要： The present invention provides a high-strength steel sheet excellent in impact resistance. The high-strength steel sheet contains predetermined contents of C, Si, Mn, P, S, Al, Ti, N, and O, with the balance being iron and inevitable impurities, and has a steel sheet structure in which, in a ⅛ thickness to ⅜ thickness region across ¼ of a sheet thickness, 1 to 8% retained austenite is contained in volume fraction, an average aspect ratio of the retained austenite is 2.0 or less, an amount of solid-solution Mn in the retained austenite is 1.1 times an average amount of Mn or more, and TiN grains having a 0.5 μm average grain diameter or less are contained, and a density of AlN grains with a 1 μm grain diameter or more is 1.0 pieces/mm2 or less, wherein a maximum tensile strength is 900 MPa or more.

公开(公告)号：US20140205855A1

公开(公告)日：2014-07-24

申请号：US14235414

申请日：2012-07-27

申请人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Akinobu Minami ,  Hajime Hasegawa ,  Chisato Wakabayashi ,  Tsuyoshi Oki

发明人： Hiroyuki Kawata ,  Naoki Maruyama ,  Akinobu Murasato ,  Akinobu Minami ,  Hajime Hasegawa ,  Chisato Wakabayashi ,  Tsuyoshi Oki

IPC分类号： C22C38/38 ,  C22C38/34 ,  C22C38/28 ,  C22C38/22 ,  C22C38/16 ,  B32B15/01 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C22C38/14

CPC分类号： C22C38/38 ,  B32B15/013 ,  C21D8/0247 ,  C22C18/00 ,  C22C18/04 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/28 ,  C22C38/34 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C25D5/36 ,  C25D5/48 ,  C25D7/0614 ,  Y10T428/12611 ,  Y10T428/12799

摘要： [Summary] The present invention provides a high-strength steel sheet excellent in impact resistance. The high-strength steel sheet contains predetermined contents of C, Si, Mn, P, S, Al, Ti, N, and O, with the balance being iron and inevitable impurities, and has a steel sheet structure in which, in a ⅛ thickness to ⅜ thickness region across ¼ of a sheet thickness, 1 to 8% retained austenite is contained in volume fraction, an average aspect ratio of the retained austenite is 2.0 or less, an amount of solid-solution Mn in the retained austenite is 1.1 times an average amount of Mn or more, and TiN grains having a 0.5 μm average grain diameter or less are contained, and a density of AlN grains with a 1 μm grain diameter or more is 1.0 pieces/mm2 or less, wherein a maximum tensile strength is 900 MPa or more.

摘要翻译： 发明内容本发明提供耐冲击性优异的高强度钢板。 高强度钢板含有预定含量的C，Si，Mn，P，S，Al，Ti，N和O，余量为铁和不可避免的杂质，并且具有钢板结构，其中在 厚度为⅜厚度区域，1/4的残留奥氏体含量为1〜8％，残留奥氏体的平均纵横比为2.0以下，残留奥氏体中的固溶Mn量为1.1 的平均粒径Mn以上，并且含有0.5μm平均粒径以下的TiN粒子，1μm以上的AlN粒子的密度为1.0个/ mm 2以下，其中，最大拉伸强度 强度为900MPa以上。

公开(公告)号：US08951366B2

公开(公告)日：2015-02-10

申请号：US13574096

申请日：2011-01-26

申请人： Kohichi Sano ,  Chisato Wakabayashi ,  Hiroyuki Kawata ,  Riki Okamoto ,  Naoki Yoshinaga ,  Kaoru Kawasaki ,  Natsuko Sugiura ,  Nobuhiro Fujita

发明人： Kohichi Sano ,  Chisato Wakabayashi ,  Hiroyuki Kawata ,  Riki Okamoto ,  Naoki Yoshinaga ,  Kaoru Kawasaki ,  Natsuko Sugiura ,  Nobuhiro Fujita

IPC分类号： C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/18 ,  C21D8/02 ,  C21D8/04 ,  C23C2/04 ,  C23C2/26 ,  C23C2/28 ,  C21D9/48

CPC分类号： C22C38/02 ,  C21D8/0436 ,  C21D8/0473 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06 ,  C23C2/04 ,  C23C2/26 ,  C23C2/28

摘要： A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 μm to 1 μm, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.

摘要翻译： 高强度冷轧钢板以质量％计含有C：0.10％至0.40％，Mn：0.5％至4.0％，Si：0.005％至2.5％，Al：0.005％至2.5％，Cr：0 ％至1.0％，其中P含量限制在0.05％以下的铁和不可避免的杂质的余量，S的量限制在0.02％以下，N的量限定为0.006％，或者 微观结构中的残余奥氏体的面积率为2％〜30％，微观结构中的面积百分比将马氏体限制在20％以下，渗碳体的平均粒径为0.01μm〜1μm，30％〜100％ 渗碳体的％的纵横比为1〜3。

公开(公告)号：US20130037180A1

公开(公告)日：2013-02-14

申请号：US13574096

申请日：2011-01-26

申请人： Kohichi Sano ,  Chisato Wakabayashi ,  Hiroyuki Kawata ,  Riki Okamoto ,  Naoki Yoshinaga ,  Kaoru Kawasaki ,  Natsuko Sugiura ,  Nobuhiro Fujita

发明人： Kohichi Sano ,  Chisato Wakabayashi ,  Hiroyuki Kawata ,  Riki Okamoto ,  Naoki Yoshinaga ,  Kaoru Kawasaki ,  Natsuko Sugiura ,  Nobuhiro Fujita

IPC分类号： C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/34 ,  C22C38/14 ,  C22C38/22 ,  C22C38/20 ,  C22C38/32 ,  C22C38/58 ,  C22C38/40 ,  C22C38/12 ,  C21D8/02 ,  C22C38/38

CPC分类号： C22C38/02 ,  C21D8/0436 ,  C21D8/0473 ,  C21D9/48 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06 ,  C23C2/04 ,  C23C2/26 ,  C23C2/28

摘要： A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 μm to 1 μm, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.

摘要翻译： 高强度冷轧钢板以质量％计含有C：0.10％至0.40％，Mn：0.5％至4.0％，Si：0.005％至2.5％，Al：0.005％至2.5％，Cr：0 ％至1.0％，其中P含量限制在0.05％以下的铁和不可避免的杂质的余量，S的量限制在0.02％以下，N的量限定为0.006％，或者 微观结构中的残余奥氏体的面积率为2％〜30％，微观结构中的面积百分比将马氏体限制在20％以下，渗碳体的平均粒径为0.01μm〜1μm，30％〜100％ 渗碳体的％的纵横比为1〜3。

公开(公告)号：US20120305144A1

公开(公告)日：2012-12-06

申请号：US13575252

申请日：2011-01-31

申请人： Riki Okamoto ,  Natsuko Sugiura ,  Kohichi Sano ,  Chisato Wakabayashi ,  Naoki Yoshinaga ,  Kaoru Kawasaki

发明人： Riki Okamoto ,  Natsuko Sugiura ,  Kohichi Sano ,  Chisato Wakabayashi ,  Naoki Yoshinaga ,  Kaoru Kawasaki

IPC分类号： B32B15/01 ,  C22C38/04 ,  C23C2/02 ,  C22C38/16 ,  C22C38/00 ,  C22C38/02 ,  C22C38/18

CPC分类号： C23C2/28 ,  C21D6/00 ,  C21D6/005 ,  C21D6/008 ,  C21D8/00 ,  C21D8/02 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0263 ,  C21D8/04 ,  C21D8/0405 ,  C21D8/0426 ,  C21D8/0436 ,  C21D8/0447 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C23C2/02 ,  C23C2/06

摘要： A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein an area ratio of equal to or higher than 50% of a total of a ferrite phase, a bainite phase, and a tempered martensite phase is contained, an area ratio of equal to or higher than 3% of a retained austenite phase is contained, and crystal grains of the retained austenite phase having a number ratio of equal to or higher than 50% satisfy Expression 1, assuming carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.

摘要翻译： 钢板，以质量％计，化学成分为C：0.05〜0.35％ 0.05％〜2.0％的Si; 0.8％〜3.0％的Mn; 0.01％〜2.0％的Al; 等于或小于0.1％的P; 等于或小于0.05的S; 等于或小于0.01的N; 余量包括铁和不可避免的杂质，其中包含等于或高于铁素体相，贝氏体相和回火马氏体相的总和的50％的面积比，面积比等于或高于 含有3％的残余奥氏体相，并且数值比等于或高于50％的残余奥氏体相的晶粒满足表达式1，假定重心位置的碳浓度为Cgc，碳浓度 在晶界是Cgb。

公开(公告)号：US09410231B2

公开(公告)日：2016-08-09

申请号：US13575252

申请日：2011-01-31

申请人： Riki Okamoto ,  Natsuko Sugiura ,  Kohichi Sano ,  Chisato Wakabayashi ,  Naoki Yoshinaga ,  Kaoru Kawasaki

发明人： Riki Okamoto ,  Natsuko Sugiura ,  Kohichi Sano ,  Chisato Wakabayashi ,  Naoki Yoshinaga ,  Kaoru Kawasaki

IPC分类号： C22C38/02 ,  C23C2/28 ,  C21D9/46 ,  C22C38/04 ,  C22C38/06 ,  C23C2/02 ,  C23C2/06 ,  C22C38/00 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16

CPC分类号： C23C2/28 ,  C21D6/00 ,  C21D6/005 ,  C21D6/008 ,  C21D8/00 ,  C21D8/02 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0263 ,  C21D8/04 ,  C21D8/0405 ,  C21D8/0426 ,  C21D8/0436 ,  C21D8/0447 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C23C2/02 ,  C23C2/06

摘要： A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein the steel sheet comprises 50% or more of a ferrite phase, a bainite phase, and a tempered martensite phase, 3% or more of a retained austenite phase, and 50% or more of the crystal grains of the retained austenite phase satisfy Expression 1, wherein a carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.

摘要翻译： 钢板，以质量％计，化学成分为0.05〜0.35％的C， 0.05％〜2.0％的Si; 0.8％〜3.0％的Mn; 0.01％〜2.0％的Al; 等于或小于0.1％的P; 等于或小于0.05的S; 等于或小于0.01的N; 余量包括铁和不可避免的杂质，其中钢板包含铁素体相，贝氏体相和回火马氏体相的50％以上，残余奥氏体相的3％以上，和50％以上 残留奥氏体相的晶粒满足式1，其中，重心位置的碳浓度为Cgc，晶界处的碳浓度为Cgb。