公开(公告)号：US20210371961A1

公开(公告)日：2021-12-02

申请号：US16975318

申请日：2019-02-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Shinji YOSHIDA ,  Yuji ARAI

IPC: C22C38/14 ,  C22C38/02 ,  C22C38/04 ,  C22C38/20 ,  C22C38/32 ,  C22C38/28 ,  C22C38/24 ,  C21D9/08

Abstract: The steel material according to the present disclosure has a chemical composition consisting of, in mass %, C: 0.10 to 0.60%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.025% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.20 to 1.50%, Mo: 0.25 to 1.50%, V: 0.01 to 0.60%, Ti: 0.002 to 0.050%, B: 0.0001 to 0.0050%, N: 0.0020 to 0.0100%, and O: 0.0100% or less, with the balance being Fe and impurities. A dislocation density ρ is 3.5×1015 m−2 or less. Among fine precipitates, the numerical proportion of precipitates for which a ratio of the Mo content is not more than 50% is 15% or more. The yield strength is in a range of 655 to 1172 MPa.

公开(公告)号：US20250043380A1

公开(公告)日：2025-02-06

申请号：US18847046

申请日：2023-03-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Kengo HATA ,  Shinji YOSHIDA ,  Rina FUJIMURA ,  Natsumi OOURA

IPC: C21D9/46 ,  C21D1/18 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14

Abstract: A cold-rolled steel sheet having a chemical composition of, in mass %: 0.10 to 0.30% C; up to 2.50% Si; 0.50 to 3.50% Mn; up to 0.100% P; up to 0.020% S; 0.010 to 0.100% Al; up to 0.0100% N; 0 to 0.100% Ti; 0 to 0.100% Nb; 0 to 0.50% V; 0 to 0.50 % Mo; 0 to 0.50% W; 0 to 0.0050% B; 0 to 0.0100% Ca; 0 to 0.0100% Mg; 0 to 0.0100% REM; and balance Fe and impurities, the microstructure containing tempered martensite and bainite in not less than 85 volume % in total, with other structure(s) being present in not more than 5 volume %, the regions where the Mn concentration in the microstructure is not lower than 8.0 mass % being present in 0.05 to 1.5 area %.

公开(公告)号：US20210180149A1

公开(公告)日：2021-06-17

申请号：US17044601

申请日：2019-03-22

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji ARAI ,  Shinji YOSHIDA ,  Atsushi SOMA ,  Hiroki KAMITANI

IPC: C21D9/08 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/30 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/10 ,  C21D6/00

Abstract: The steel pipe according to the present disclosure contains a chemical composition consisting of, in mass %, C: 0.25 to 0.50%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, P: 0.025% or less, S: 0.0050% or less, Al: 0.005 to 0.100%, Cr: 0.30 to 1.50%, Mo: 0.25 to 3.00%, Ti: 0.002 to 0.050%, N: 0.0010 to 0.0100% and O: 0.0030% or less, with the balance being Fe and impurities. The steel pipe contains an amount of dissolved C within a range of 0.010 to 0.050 mass %. The tensile yield strength in the axial direction and the circumferential direction is 862 to 965 MPa, and the yield ratio in the axial direction is 90% or more. The tensile yield strength in the circumferential direction is 30 to 80 MPa higher than the compressive yield strength in the circumferential direction.

公开(公告)号：US20210032734A1

公开(公告)日：2021-02-04

申请号：US17043306

申请日：2019-03-22

Applicant: NIPPON STEEL CORPORATION

Inventor： Yuji ARAI ,  Shinji YOSHIDA ,  Atsushi SOMA ,  Hiroki KAMITANI

IPC: C22C38/54 ,  C21D8/10 ,  C21D9/08 ,  C22C38/42 ,  C22C38/44 ,  C22C38/50 ,  C22C38/46 ,  C22C38/48 ,  C22C38/52 ,  C22C38/00 ,  C22C38/06 ,  C22C38/02 ,  C22C38/04

Abstract: The steel pipe according to the present disclosure contains a chemical composition consisting of, in mass %, C: more than 0.50 to 0.65%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, P: 0.025% or less, S: 0.0050% or less, Al: 0.005 to 0.100%, Cr: 0.30 to 1.50%, Mo: 0.25 to 3.00%, Ti: 0.002 to 0.050%, N: 0.0010 to 0.0100% and O: 0.0030% or less, with the balance being Fe and impurities. The steel pipe contains an amount of dissolved C within a range of 0.010 to 0.060 mass %. The tensile yield strength in the axial direction and the circumferential direction is 862 to 1069 MPa, and the yield ratio in the axial direction is 90% or more. The tensile yield strength in the circumferential direction is 30 to 80 MPa higher than the compressive yield strength in the circumferential direction.

公开(公告)号：US20210025021A1

公开(公告)日：2021-01-28

申请号：US16981435

申请日：2019-03-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroki KAMITANI ,  Takanori TANAKA ,  Atsushi SOMA ,  Keiichi KONDO ,  Hideki MITSUNARI ,  Seiya OKADA ,  Takuya MATSUMOTO ,  Shinji YOSHIDA ,  Yuji ARAI

IPC: C21D9/08 ,  B21D41/04 ,  C21D8/10

Abstract: A seamless steel pipe heat-treatment-finishing-treatment continuous facility includes: a heat treatment apparatus; a steel pipe inspection apparatus which performs a test for a surface defect and/or an inner defect of the seamless steel pipe, the steel pipe inspection apparatus being disposed downstream of the heat treatment apparatus; a main transfer mechanism which forms a main transfer path MT for transferring the seamless steel pipe, discharged from the heat treatment apparatus, to the steel pipe inspection apparatus disposed downstream of the heat treatment apparatus; and a first forced steel pipe-temperature reduction apparatus which forcibly reduces a temperature of the seamless steel pipe on the main transfer path MT, the first forced steel pipe-temperature reduction apparatus being disposed on the main transfer path MT at a position downstream of the heat treatment apparatus and upstream of the steel pipe inspection apparatus.

公开(公告)号：US20220325393A1

公开(公告)日：2022-10-13

申请号：US17596474

申请日：2020-08-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Shinji YOSHIDA ,  Yuji ARAI ,  Kuniaki ITOH ,  Takuya OKAMURA

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

Abstract: The steel material according to the present disclosure has a chemical composition consisting of, in mass %, C: more than 0.20 to 0.35%, Si: 0.05 to 1.00%, Mn: 0.02 to 1.00%, P: 0.025% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.40 to 1.50%, Mo: 0.30 to 1.50%, Ti: 0.002 to 0.050%, B: 0.0001 to 0.0050%, N: 0.0100% or less and O: 0.0100% or less, with the balance being Fe and impurities, and satisfies Formula (1) and Formula (2) described in the description. The yield strength is 862 MPa or more. A numerical proportion of precipitates having an equivalent circular diameter within a range of 20 to 300 nm among precipitates having an equivalent circular diameter of 20 nm or more in the steel material is 0.85 or more.

公开(公告)号：US20210269902A1

公开(公告)日：2021-09-02

申请号：US17253229

申请日：2019-09-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Shinji YOSHIDA ,  Yuji ARAI

IPC: C22C38/32 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/28 ,  C21D8/10

Abstract: The steel material according to the present disclosure has a chemical composition consisting of, in mass %, C: 0.20 to 0.35%, Si: 0.05 to 1.00%, Mn: 0.01 to 1.00%, P: 0.025% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr 0.25 to 0.80%, Mo: 0.20 to 2.00%, Ti: 0.002 to 0.050%, B: 0.0001 to 0.0050%, N: 0.0020 to 0.0100% and O: 0.0100% or less, with the balance being Fe and impurities, and satisfying Formula (1). A number density of precipitates having an equivalent circular diameter of 400 nm or more is 0.150 particles/μm2 or less. The yield strength is within a range of 655 to 965 MPa. A dislocation density ρ is 7.0×1014 m−2 or less. 5×Cr—Mo-2×(V+Ti)≤3.00  (1)

公开(公告)号：US20210017635A1

公开(公告)日：2021-01-21

申请号：US16980671

申请日：2019-03-25

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroki KAMITANI ,  Atsushi SOMA ,  Shinji YOSHIDA ,  Yuji ARAI ,  Seiya OKADA

IPC: C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/42 ,  C22C38/22 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: The steel material according to the present disclosure contains a chemical composition consisting of, in mass %, C: 0.20 to 0.50%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, P: 0.030% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.10 to 1.50%, Mo: 0.25 to 1.50%, Ti: 0.002 to 0.050%, N: 0.0100% or less and O: 0.0100% or less, with the balance being Fe and impurities. The steel material contains an amount of dissolved C within a range of 0.010 to 0.050 mass %. The steel material also has a yield strength within a range of 655 to less than 862 MPa, and a yield ratio of the steel material is 85% or more.

公开(公告)号：US20230366070A1

公开(公告)日：2023-11-16

申请号：US18044249

申请日：2021-10-29

Applicant: NIPPON STEEL CORPORATION

Inventor： Shinji YOSHIDA ,  Yuji ARAI ,  Hiroyuki FUJI

IPC: C22C38/34 ,  C22C38/00 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/24 ,  C22C38/28 ,  C22C38/32 ,  C21D9/08

CPC classification number: C22C38/34 ,  C22C38/001 ,  C22C38/002 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/24 ,  C22C38/28 ,  C22C38/32 ,  C21D9/08

Abstract: The steel material according to the present disclosure contains, in mass %, C: 0.20 to 0.45%, Si: 1.36 to 3.20%, Mn: 0.02 to 1.00%, P: 0.025% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.20 to 1.50%, Mo: 0.36 to 1.50%, V: 0.01 to 0.90%, Ti: 0.002 to 0.050%, B: 0.0001 to 0.0050%, N: 0.0100% or less, and O: 0.0100% or less, and satisfies Formula (1). A yield strength σYS is 758 MPa or more. The yield strength σYS and a dislocation density ρ satisfy Formula (2).


27×Mn+9×Cr−14×Mo−770×C2+760×C−11×Si2+4×Si>85   (1)



691

公开(公告)号：US20220098712A1

公开(公告)日：2022-03-31

申请号：US17422870

申请日：2020-02-13

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroki KAMITANI ,  Yohei OTOME ,  Atsushi SOMA ,  Taro OE ,  Nobuaki KOMATSUBARA ,  Shinji YOSHIDA ,  Yuji ARAI

IPC: C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/30 ,  C22C38/20 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: A steel material according to the present disclosure has a chemical composition consisting of, in mass %: C: 0.20 to 0.45%, Si: 0.05 to 1.00%, Mn: 0.01 to 1.00%, P: 0.030% or less, S: 0.0050% or less, Al: 0.005 to 0.100%, Cr: 0.60 to 1.50%, Mo: more than 1.00 to 2.00%, Ti: 0.002 to 0.020%, V: 0.05 to 0.30%, Nb: 0.005 to 0.100%, B: 0.0005 to 0.0040%, N: 0.0100% or less, O: less than 0.0020%, and the balance being Fe and impurities, and satisfying Formula (1) described in the specification. A grain diameter of a prior-austenite grain is 11.0 μm or less, and an average area of precipitate which is precipitated in a prior-austenite grain boundary is 10.0×10−3 μm2 or less. A yield strength is 758 to 862 MPa.