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公开(公告)号：US20220010396A1
公开(公告)日：2022-01-13
申请号：US17283476
申请日：2019-10-21
Applicant: NIPPON STEEL CORPORATION
Inventor： Tatsuo YOKOI , Teruki HAYASHIDA , Mutsumi SAKAKIBARA , Jun ANDO , Shinsuke KAI , Hiroshi SHUTO
IPC: C21D9/46 , B21B1/02 , C22C38/58 , C22C38/16 , C22C38/14 , C22C38/12 , C22C38/06 , C22C38/02 , C22C38/00 , C21D8/02 , C21D6/00 , C23G1/08
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, and in a case where the thickness is denoted by t, the metallographic structure at a t/4 position from the surface contains one or both of tempered martensite and lower bainite at a volume percentage of 90% or more, the tensile strength is 980 MPa or more, and the average Ni concentration on the surface is 7.0% or more.
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公开(公告)号：US20210395852A1
公开(公告)日：2021-12-23
申请号：US17285013
申请日：2019-10-21
Applicant: NIPPON STEEL CORPORATION
Inventor： Tatsuo YOKOI , Hiroshi SHUTO , Teruki HAYASHIDA , Jun ANDO , Mutsumi SAKAKIBARA
IPC: C21D9/46 , C22C38/58 , C22C38/16 , C22C38/14 , C22C38/12 , C22C38/10 , C22C38/06 , C22C38/02 , C22C38/00 , C23G1/08 , C21D8/02 , C21D6/00
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in which in a case where the thickness is denoted by t, a metallographic structure at a t/4 position from the surface includes, by area fraction, 77.0% to 97.0% of bainite or tempered martensite, 0% to 5.0% of ferrite, 0% to 5.0% of pearlite, 3.0% or more of residual austenite, and 0% to 10.0% of martensite, in the metallographic structure, the average grain size excluding the residual austenite is 7.0 μm or less, the average number density of iron-based carbides having a diameter of 20 nm or more is 1.0×106 carbides/mm2 or more, a tensile strength is 980 MPa or more, and an average Ni concentration on the surface is 7.0% or more.
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公开(公告)号：US20240384378A1
公开(公告)日：2024-11-21
申请号：US18689095
申请日：2022-09-14
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Kazumasa TSUTSUI , Shunsuke KOBAYASHI , Akifumi SAKAKIBARA , Jun ANDO , Toshiki SUGIYAMA
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, has a microstructure including, by area %, residual austenite of less than 3.0%, ferrite of 15.0% or more and less than 60.0%, and pearlite of less than 5.0%, in which an entropy value obtained by analyzing an SEM image of the microstructure using a gray-level co-occurrence matrix method is 10.7 or more, an inverse difference normalized value is 1.020 or more, a cluster shade value is −8.0×105 to 8.0×105, and a standard deviation of an Mn concentration is 0.60 mass % or less, and has a tensile strength of 980 MPa or more.
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公开(公告)号：US20230041990A1
公开(公告)日：2023-02-09
申请号：US17787857
申请日：2021-02-05
Applicant: NIPPON STEEL CORPORATION
Inventor： Jun ANDO , Teruki HAYASHIDA , Tatsuo YOKOI , Akifumi SAKAKIBARA
Abstract: A hot-rolled steel sheet has, as a chemical composition, by mass %: C: 0.01% to 0.30%; Si: 0.01% to 3.00%; Mn: 0.20% to 3.00%; P: 0.030% or less; S: 0.030% or less; Al: 0.001% to 2.000%; N: 0.0100% or less; and Ni: 0.02% to 0.50%, in which among measurement points at which elemental analysis is performed at a measurement pitch of 1 μm using an EPMA in a region of 250 μm×250 μm on a surface, the percentage of measurement points having a Ni content of 0.5 mass % or more is 10% to 70%.
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Patent Agency Ranking
公开(公告)号：US20220119902A1
公开(公告)日：2022-04-21
申请号：US17422406
申请日：2020-01-30
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Koutarou HAYASHI , Hiroshi KAIDO , Akifumi SAKAKIBARA , Jun ANDO , Tetsu ASATO
IPC: C21D8/02 , C21D9/46 , C22C38/00 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/54
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in which a metal microstructure contains, by area %, 3.0% or more of residual austenite, has a ratio L52/L7 of a length L52 of a grain boundary having a crystal orientation difference of 52° to a length L7 of a grain boundary having a crystal orientation difference of 7° about a direction of 0.10 or more and 0.18 or less, has a standard deviation of a Mn concentration of 0.60 mass % or less, and has a tensile strength of 980 MPa or more.
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公开(公告)号：US20230295783A1
公开(公告)日：2023-09-21
申请号：US18020598
申请日：2021-06-15
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Kazumasa TSUTSUI , Koutarou HAYASHI , Akifumi SAKAKIBARA , Jun ANDO , Toshiki SUGIYAMA
CPC classification number: C22C38/14 , C22C38/12 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/002 , C22C38/001 , C21D9/46 , C21D8/0205 , C21D8/0226 , C21D2211/001 , C21D2211/005 , C21D2211/009
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure, in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%, an E value that indicates periodicity of the microstructure is 10.7 or more, and an I value that indicates uniformity of the microstructure is 1.020 or more, a standard deviation of a Mn concentration is 0.60 mass % or less, and a tensile strength is 980 MPa or more.
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公开(公告)号：US20230257845A1
公开(公告)日：2023-08-17
申请号：US18016141
申请日：2021-06-15
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Kazumasa TSUTSUI , Koutarou HAYASHI , Akifumi SAKAKIBARA , Jun ANDO , Mitsuru YOSHIDA
IPC: C21D9/46 , C22C38/00 , C22C38/50 , C22C38/16 , C22C38/14 , C22C38/12 , C22C38/08 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/10 , C21D8/02 , C21D1/84
CPC classification number: C21D9/46 , C22C38/005 , C22C38/50 , C22C38/16 , C22C38/14 , C22C38/12 , C22C38/08 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/008 , C22C38/002 , C22C38/001 , C22C38/10 , C21D8/0226 , C21D8/0205 , C21D1/84 , C21D2211/001 , C21D2211/005 , C21D2211/009
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure, in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%, an E value that indicates periodicity of the microstructure is 10.7 or more, and an I value that indicates uniformity of the microstructure is less than 1.020, a standard deviation of a Mn concentration is 0.60 mass % or less, and a tensile strength is 980 MPa or more.
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公开(公告)号：US20230055479A1
公开(公告)日：2023-02-23
申请号：US17792985
申请日：2020-12-11
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Kazumasa TSUTSUI , Jun ANDO , Koutarou HAYASHI , Akifumi SAKAKIBARA , Shunsuke KOBAYASHI
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure contains, by area %, less than 3.0% of residual austenite, 15.0% or more and less than 60.0% of ferrite, and less than 5.0% of pearlite, has a ratio L60/L7 of a length L60 of a grain boundary having a crystal misorientation of 60° to a length L7 of a grain boundary having a crystal misorientation of 7° about a direction of 0.60 or more, has a standard deviation of a Mn concentration of 0.60 mass % or less, and has a tensile strength of 980 MPa or more.
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公开(公告)号：US20220389554A1
公开(公告)日：2022-12-08
申请号：US17760933
申请日：2020-09-04
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroshi SHUTO , Kazumasa TSUTSUI , Koutarou HAYASHI , Akifumi SAKAKIBARA , Jun ANDO , Shota ENDO
Abstract: This hot-rolled steel sheet has a predetermined chemical composition, in which a microstructure contains, by area %, less than 3.0% of residual austenite, 15.0% or more and less than 60.0% of ferrite, and less than 5.0% of pearlite, has a ratio L60/L7 of a length L60 of a grain boundary having a crystal misorientation of 60° to a length L7 of a grain boundary having a crystal misorientation of 7° about a direction of less than 0.60, has a standard deviation of a Mn concentration of 0.60 mass % or less, and has a tensile strength of 980 MPa or more.
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