公开(公告)号：US20220340989A1

公开(公告)日：2022-10-27

申请号：US17636714

申请日：2020-06-19

Applicant: JFE STEEL CORPORATION

Inventor： Yuji TANAKA ,  Hidekazu MINAMI ,  Naoki TAKAYAMA ,  Takako YAMASHITA

IPC: C21D9/46 ,  B32B15/01 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C23C2/40 ,  C23C2/28

Abstract: A high-strength cold-rolled steel sheet having a high yield ratio and excellent stretch flangeability and a method for manufacturing the steel sheet. The high-strength cold-rolled steel sheet has a chemical composition including, by mass %, C: 0.10 to 0.30%, Si: 0.50 to 2.00%, Mn: 2.5 to 4.0%, P: 0.050% or less, S: 0.020% or less, Al: 0.10% or less, N: 0.01% or less, Ti: 0.100% or less, and B: 0.0003 to 0.0030%, with the balance being Fe and incidental impurities. N and Ti satisfy a specified formula, and the total area fraction of martensite and bainite is 95% or more. The number density of bainite grains having an area of 3 μm2 or more and a carbon concentration of less than 0.7C is 1200 grains/mm2 or less.

公开(公告)号：US20190309384A1

公开(公告)日：2019-10-10

申请号：US16092272

申请日：2016-04-19

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke TERAZAWA ,  Naoki TAKAYAMA ,  Kenji HAYASHI ,  Kazukuni HASE

IPC: C21D8/02 ,  C21D6/00 ,  C22C38/58 ,  C22C38/46 ,  C22C38/42 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/20 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: An abrasion-resistant steel plate that can achieve both gas cutting cracking resistance and abrasion resistance at low cost is provided. An abrasion-resistant steel plate comprises: a chemical composition containing, in mass %, C: more than 0.34% and 0.50% or less, Si: 0.01% to 1.0%, Mn: 0.30% to 2.00%, P: 0.015% or less, S: 0.005% or less, Cr: 0.01% to 2.00%, Al: 0.001% to 0.100%, N: 0.01% or less, and a balance consisting of Fe and inevitable impurities; and a microstructure in which a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, and a prior austenite grain size at the mid-thickness of the abrasion-resistant steel plate is 80 μm or less, wherein hardness at a depth of 1 mm from the surface of the abrasion-resistant steel plate is 560 HBW 10/3000 or more in Brinell hardness, and a concentration [Mn] of Mn in mass % and a concentration [P] of P in mass % in a plate thickness central segregation area satisfy 0.04[Mn]+[P]

公开(公告)号：US20230183845A1

公开(公告)日：2023-06-15

申请号：US17999214

申请日：2021-05-25

Applicant: JFE STEEL CORPORATION

Inventor： Shigeki KITSUYA ,  Naoki TAKAYAMA ,  Tomoyuki YOKOTA

IPC: C22C38/00 ,  C22C38/26 ,  C22C38/06 ,  C22C38/58 ,  C22C38/02 ,  C22C38/28 ,  C22C38/32 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/52 ,  C21D8/02 ,  C21D1/18

CPC classification number: C22C38/001 ,  C22C38/26 ,  C22C38/06 ,  C22C38/58 ,  C22C38/02 ,  C22C38/28 ,  C22C38/32 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/52 ,  C21D8/0226 ,  C21D1/18

Abstract: Provided is an abrasion-resistant steel plate excellent in both abrasion resistance and wide bending workability. An abrasion-resistant steel plate comprises a specific chemical composition, wherein a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, hardness at a depth of 1 mm from the surface is 420 HBW 10/3000 to 560 HBW 10/3000 in Brinell hardness, and a transverse direction hardness difference is 30Hv10 or less in Vickers hardness, the transverse direction hardness difference being defined as a difference in the hardness at a depth of 1 mm from the surface between two points adjacent at intervals of 10 mm in a transverse direction of the abrasion-resistant steel plate.

公开(公告)号：US20190203314A1

公开(公告)日：2019-07-04

申请号：US16092553

申请日：2016-04-19

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke TERAZAWA ,  Naoki TAKAYAMA ,  Kenji HAYASHI ,  Kazukuni HASE

IPC: C21D9/46 ,  C22C38/58 ,  C22C38/32 ,  C22C38/50 ,  C22C38/26 ,  C22C38/24 ,  C22C38/44 ,  C22C38/20 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  B22D11/041 ,  B22D11/00

CPC classification number: C21D9/46 ,  B22D11/001 ,  B22D11/041 ,  B22D11/1206 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D2211/001 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/18 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/40 ,  C22C38/44 ,  C22C38/50 ,  C22C38/58

Abstract: An abrasion-resistant steel plate comprises: a specific chemical composition; and a microstructure in which a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, and a prior austenite grain size in a plate thickness central part at the mid-thickness of the abrasion-resistant steel plate is 80 μm or less, wherein hardness at a depth of 1 mm from the surface of the abrasion-resistant steel plate is 460 to 590 HBW 10/3000 in Brinell hardness, and a concentration [Mn] of Mn in mass % and a concentration [P] of P in mass % in a plate thickness central segregation area satisfy 0.04[Mn]+[P]

公开(公告)号：US20200248290A1

公开(公告)日：2020-08-06

申请号：US16488701

申请日：2018-02-02

Applicant: JFE STEEL CORPORATION

Inventor： Naoki TAKAYAMA ,  Yusuke TERAZAWA ,  Yoshiaki MURAKAMI ,  Kazukuni HASE ,  Yusaku TAKEMURA ,  Yasuhiro MUROTA

IPC: C22C38/54 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/52 ,  C22C38/50 ,  C21D8/02 ,  C21D9/46

Abstract: Provided is an abrasion-resistant steel plate which has high hardness up to the mid-thickness part thereof although the steel plate is 50 mm or more, and can be manufactured at low cost. The abrasion-resistant steel plate has a specific chemical composition having DI* of 120 or more, where DI* is defined by the following Formula (1): DI*=33.85×(0.1×C)0.5×(0.7×Si+1)×(3.33×Mn+1)×(0.35×Cu+1)×(0.36×Ni+1)×(2.16×Cr+1)×(3×Mo+1)×(1.75×V+1)×(1.5×W+1) . . . (1), has HB1 of 360 HBW10/3000 to 490 HBW10/3000, HB1 being a Brinell hardness at a depth of 1 mm from a surface, has a hardness ratio, HB1/2 to HB1, of 75% or more, HB1/2 being a Brinell hardness at a mid-thickness position, and has a plate thickness of 50 mm or more.

公开(公告)号：US20190119772A1

公开(公告)日：2019-04-25

申请号：US16092538

申请日：2016-04-19

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke TERAZAWA ,  Naoki TAKAYAMA ,  Kenji HAYASHI ,  Kazukuni HASE

IPC: C21D8/02 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/00 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/54 ,  C22C38/50 ,  C21D9/46 ,  B22D11/00

Abstract: An abrasion-resistant steel plate comprises: a chemical composition containing, in mass %, C: 0.20% to 0.45%, Si: 0.01% to 1.0%, Mn: 0.3% to 2.5%, P: 0.020% or less, S: 0.01% or less, Cr: 0.01% to 2.0%, Ti: 0.10% to 1.00%, B: 0.0001% to 0.0100% , Al: 0.1% or less, N: 0.01% or less, and a balance consisting of Fe and inevitable impurities; and a microstructure in which a volume fraction of martensite is 90% or more, and a prior austenite grain size is 80 μm or less, wherein a number density of TiC precipitate having a size of 0.5 μm or more is 400 particles/mm2 or more, and a Mn content [Mn] and a P content [P] in a plate thickness central segregation area satisfy 0.04[Mn]+[P]

公开(公告)号：US20250154632A1

公开(公告)日：2025-05-15

申请号：US18836003

申请日：2023-01-18

Applicant: JFE STEEL CORPORATION

Inventor： Kyono YASUDA ,  Naoki TAKAYAMA ,  Kazuhiko SHIOTANI

IPC: C22C38/04 ,  C21D1/84 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06

Abstract: A high strength steel plate having excellent ammonia SCC resistance and low-temperature toughness for use in storage tanks and the like used to contain liquefied gas in energy transport ships. The steel plate has a defined chemical composition and has hardness properties such that, at a 0.5 mm depth position from the surface of the steel plate, average hardness is 210 HV or less and variation of the average hardness is 50 HV or less, and a metallic microstructure where, at a 0.5 mm depth position from the surface of the steel plate, a volume fraction of bainitic microstructure is 90% or more and, at a ½ thickness position of the steel plate, a volume fraction of bainitic microstructure is 20% or more and a total volume fraction of ferritic microstructure and bainitic microstructure is 60% or more.

公开(公告)号：US20220333227A1

公开(公告)日：2022-10-20

申请号：US17753552

申请日：2020-08-17

Applicant: JFE STEEL CORPORATION

Inventor： Naoki TAKAYAMA ,  Shigeki KITSUYA ,  Yoshiaki MURAKAMI

IPC: C22C38/38 ,  C22C38/02 ,  C21D8/04

Abstract: The steel plate has a specific chemical composition, and a microstructure where a volume fraction of martensite at a depth of 1 mm from a surface of the steel plate is 95% or more, and at a depth of 1 mm from a surface of the steel plate, a Vickers hardness at 400° C. is 288 or more, and a Brinell hardness at 25° C. is 360 HBW10/3000 to 490 HBW10/3000.

公开(公告)号：US20190062860A1

公开(公告)日：2019-02-28

申请号：US16092530

申请日：2016-04-19

Applicant: JFE STEEL CORPORATION

Inventor： Yusuke TERAZAWA ,  Naoki TAKAYAMA ,  Kenji HAYASHI ,  Kazukuni HASE

IPC: C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/38 ,  C22C38/58

Abstract: An abrasion-resistant steel plate comprises: a specific chemical composition; and a microstructure in which a volume fraction of martensite at a depth of 1 mm from a surface of the abrasion-resistant steel plate is 90% or more, and a prior austenite grain size at the mid-thickness of the abrasion-resistant steel plate is 80 μm or less, wherein hardness at a depth of 1 mm from the surface of the abrasion-resistant steel plate is 360 to 490 HBW 10/3000 in Brinell hardness, and a concentration [Mn] of Mn in mass % and a concentration [P] of P in mass % in a plate thickness central segregation area satisfy 0.04[Mn]+[P]