公开(公告)号：EP3330396A4

公开(公告)日：2018-06-06

申请号：EP16830066

申请日：2016-07-28

申请人： JFE STEEL CORP

发明人： KAWAMURA KENJI ,  KOHSAKA NORIAKI ,  FUNAKAWA YOSHIMASA ,  AOYAMA MAI ,  SUZUKI YOSHITSUGU

IPC分类号： C22C38/00 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C8/14

CPC分类号： C21D9/46 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23C8/14

摘要： Provided are a cold-rolled steel sheet which can preferably be used for manufacturing a high-strength galvanized steel sheet excellent in terms of coating adhesiveness and surface appearance and methods for manufacturing the steel sheets. The cold-rolled steel sheet has a specified chemical composition, in which the Mn concentration in a surface layer of the steel sheet satisfies relational expression (1) and relational expression (2) below. 8 ‰¤ C p / C c × Mn C min / C c × Mn ‰¤ 2.5 C p : maximum Mn concentration in a region within 0.5 µm of the surface of a steel sheet in the thickness direction C c : average Mn concentration in a region from a position located 5 µm from a surface of a steel sheet in the thickness direction to a position located 5 µm from an opposite surface in the thickness direction C min : minimum Mn concentration in a region from 0.5 µm to 5 µm from the surface of a steel sheet in the thickness direction Mn: Mn content (mass%)

公开(公告)号：EP3276021A4

公开(公告)日：2018-03-14

申请号：EP15887414

申请日：2015-08-20

申请人： JFE STEEL CORP

发明人： KAWAMURA KENJI ,  KOHSAKA NORIAKI ,  NISHIMURA YASUHIRO

IPC分类号： C22C38/00 ,  C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/28 ,  C22C38/42 ,  C22C38/44 ,  C22C38/60

CPC分类号： C21D9/46 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/28 ,  C22C38/42 ,  C22C38/44 ,  C22C38/60

摘要： A high-strength steel sheet excellent in punchability and having a TS of 780 MPa or more and a method for producing the steel sheet are provided. The high-strength steel sheet has a tensile strength of 780 MPa or more and has a specific chemical composition and a steel structure including a ferrite phase, a martensite phase, and a bainite phase. The area fraction of the martensite phase is from 20% to 50% inclusive. The martensite phase includes crystal grains with an average crystal grain diameter of less than 1.0 µm at an area fraction of 5 to 30%, crystal grains with an average crystal grain diameter of 1.0 to 4.0 µm at an area fraction of 70 to 95, and crystal grains with an average crystal grain diameter of more than 4.0 µm at an area fraction of less than 5%.

公开(公告)号：EP3266894A4

公开(公告)日：2018-04-04

申请号：EP16758577

申请日：2016-01-14

申请人： JFE STEEL CORP

发明人： KOHSAKA NORIAKI ,  FUNAKAWA YOSHIMASA ,  SAKURAI MICHITAKA ,  SUZUKI YOSHIKAZU

IPC分类号： C22C38/00 ,  C21D9/46 ,  C22C18/00 ,  C22C38/14 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC分类号： C21D9/46 ,  C22C18/00 ,  C22C38/00 ,  C22C38/14 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

摘要： A high-strength steel sheet has a composition containing C: 0.09% to 0.17%, Si: 0.6% to 1.7%, Mn: 3.5% or less, P: 0.03% or less, S: 0.005% or less, Al: 0.08% or less, N: 0.006% or less, Ti: 0.05% or less, and B: 0.0002% to 0.0030% on a mass basis, the remainder being Fe and inevitable impurities, and also has a steel sheet microstructure containing less than 20% (including 0%) of a ferrite phase, 75% or more (including 100%) of a tempered martensite phase, 10% or less (including 0%) of an untempered martensite phase, and less than 5% (including 0%) of a retained austenite phase in terms of area fraction. The tempered martensite phase has a Vickers hardness of 280 to 340 and a tensile strength of 950 MPa to 1,120 MPa.

公开(公告)号：EP3257959A4

公开(公告)日：2017-12-20

申请号：EP15887415

申请日：2015-08-20

申请人： JFE STEEL CORP

发明人： KAWAMURA KENJI ,  KOHSAKA NORIAKI ,  NISHIMURA YASUHIRO

IPC分类号： C22C38/00 ,  C21D9/46 ,  C22C38/14 ,  C22C38/60

CPC分类号： C21D9/46 ,  C22C38/00 ,  C22C38/14 ,  C22C38/60

摘要： A high-strength steel sheet excellent in punchability and having a TS of 780 MPa or more and a method for producing the steel sheet are provided. The high-strength steel sheet has a tensile strength of 780 MPa or more and has a specific chemical composition and a steel structure containing a ferrite phase at an area fraction of from 70% to 90% inclusive and a martensite phase at an area fraction of from 10% to 30% inclusive. The amount of non-recrystallized ferrite contained in the ferrite phase is from 30% to 50% inclusive. In the martensite phase, the area fraction of crystal grains with an aspect ratio of from 1.0 to 1.5 inclusive is 40% to 100%.

公开(公告)号：EP2578714A4

公开(公告)日：2015-05-27

申请号：EP11789731

申请日：2011-05-23

申请人： JFE STEEL CORP

发明人： KOHSAKA NORIAKI ,  SETO KAZUHIRO ,  KAWABE HIDETAKA ,  TANAKA YASUSHI

IPC分类号： C22C38/00 ,  B21B3/00 ,  C21D9/46 ,  C22C38/06 ,  C22C38/58

CPC分类号： C21D8/0263 ,  C21D6/005 ,  C21D8/0226 ,  C21D9/46 ,  C21D2211/002 ,  C21D2211/003 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/22 ,  C22C38/24 ,  C22C38/38

公开(公告)号：EP2431491A4

公开(公告)日：2013-04-03

申请号：EP10775017

申请日：2010-05-11

申请人： JFE STEEL CORP

发明人： KOHSAKA NORIAKI ,  SETO KAZUHIRO ,  SUGIHARA REIKO ,  WATANABE MASAHIDE ,  TANAKA YASUSHI

IPC分类号： C22C38/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14

CPC分类号： C22C38/04 ,  B21B3/00 ,  C21D8/0226 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/004 ,  C21D2211/005 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/06 ,  C22C38/14