公开(公告)号：US20250129461A1

公开(公告)日：2025-04-24

申请号：US18689942

申请日：2022-10-04

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yuji ARAI

IPC: C22C38/58 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C22C38/54 ,  C22C38/60

Abstract: A duplex stainless steel material that has excellent general corrosion resistance and pitting resistance in a supercritical corrosive environment in which SOX gas and O2 gas are contained in a supercritical CO2 gas is provided. A duplex stainless steel material of the present disclosure has the chemical composition described in the description, and in the duplex stainless steel material, on a precondition that the content of each element is within a range described in the description, Fn defined by Formula (1) is 44.0 or more, and a total number per 1 mm2 of Mn sulfides having an equivalent circular diameter of 1.0 μm or more and Ca sulfides having an equivalent circular diameter of 2.0 μm or more is 0.50/mm2 or less. Fn = Cr + 3.3 ( Mo + 0.5 W ) + 16 ⁢ N + 2 ⁢ Ni + Cu + 2 ⁢ Co + 10 ⁢ Sn ( 1 ) Where, the content in mass % of a corresponding element is substituted for each symbol of an element in Formula (1).

公开(公告)号：US20250066891A1

公开(公告)日：2025-02-27

申请号：US18724764

申请日：2023-02-16

Applicant: NIPPON STEEL CORPORATION

Inventor： Hiroki KAMITANI ,  Yuji ARAI ,  Jin KAWASAKI ,  Keiichi KONDO

IPC: C22C38/32 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28

Abstract: A steel material according to the present disclosure consists of, in mass %, C: 0.15 to 0.45%, Si: 0.05 to 1.00%, Mn: 0.05 to 0.30%, P: 0.030% or less, S: 0.0050% or less, Al: 0.005 to 0.100%, Cr: 0.30 to 1.10%, Mo: 0.40 to 2.00%, Ti: 0.002 to 0.020%, Nb: 0.002 to 0.100%, B: 0.0005 to 0.0040%, N: 0.0100% or less, and O: less than 0.0040%, with the balance being Fe and impurities, and has a yield strength of 862 MPa or more. In the steel material, a number density of Si oxides which have a major axis of 5.0 μm or more is 5/100 mm2 or less, and in a case where the yield strength is 931 MPa or more, the number density of the Si oxides is 5/200 mm2 or less.

公开(公告)号：US20240401177A1

公开(公告)日：2024-12-05

申请号：US18691200

申请日：2022-10-04

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yuji ARAI

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

Abstract: A duplex stainless steel material that has excellent general corrosion resistance and pitting resistance in a supercritical corrosive environment in which SOX gas and O2 gas are contained in a supercritical CO2 gas is provided. A duplex stainless steel material of the present disclosure has the chemical composition described in the description, and in the duplex stainless steel material, on a precondition that the content of each element is within a range described in the description, Fn defined by Formula (1) is 57.0 or more, and a total number per 1 mm2 of Mn sulfides having an equivalent circular diameter of 1.0 μm or more and Ca sulfides having an equivalent circular diameter of 2.0 μm or more is 0.50/mm2 or less. Fn = Cr + 3.3 ( M ⁢ o + 0 . 5 ⁢ W ) + 1 ⁢ 6 ⁢ N + 2 ⁢ N ⁢ i + C ⁢ u + 2 ⁢ C ⁢ o + 10 ⁢ Sn ( 1 ) Where, the content in mass % of a corresponding element is substituted for each symbol of an element in Formula (1).

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：US20250146112A1

公开(公告)日：2025-05-08

申请号：US18837961

申请日：2023-05-12

Applicant: NIPPON STEEL CORPORATION

Inventor： Kyohei KANKI ,  Daisuke MATSUO ,  Yuji ARAI

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

Abstract: A martensitic stainless steel material having high strength, and having excellent corrosion resistance in a corrosive environment in which SOx or NOx is mixed is provided. The martensitic stainless steel material according to the present disclosure satisfies a chemical composition described herein, and satisfies Formula (1). The yield strength is 862 MPa or more. In the martensitic stainless steel material, a number ratio of Mg oxides having an equivalent circular diameter of 2.0 μm or more with respect to Ca oxides having an equivalent circular diameter of 2.0 μm or more, Ca sulfides having an equivalent circular diameter of 2.0 μm or more, and the Mg oxides having an equivalent circular diameter of 2.0 μm or more is 45.0% or more. 0.001 ≤ Ca + Mg ≤ 0.005 ( 1 ) Where, a content of a corresponding element in percent by mass is substituted for each symbol of an element in Formula (1).

公开(公告)号：US20230203631A1

公开(公告)日：2023-06-29

申请号：US17995368

申请日：2021-04-15

Applicant: NIPPON STEEL CORPORATION

Inventor： Keiichi KONDO ,  Yuji ARAI ,  Keiichi NAKAMURA ,  Taro OE ,  Takenori KURAMOTO ,  Yosuke TAKEDA ,  Hiroki KAMITANI

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

CPC classification number: C22C38/54 ,  C21D9/08 ,  C22C38/001 ,  C22C38/02 ,  C22C38/002 ,  C22C38/04 ,  C22C38/005 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C21D2211/001

Abstract: The steel material according to the present disclosure consists of, in mass%, C: 0.15 to 0.45%, Si: 0.05 to 1.00%, Mn: 0.05 to less than 0.80%, P: 0.030% or less, S: 0.0100% or less, Al: 0.100% or less, Cr: 0.30 to 1.50%, Mo: 0.25 to 2.00%, Ti: 0.001 to 0.015%, N: 0.0100% or less, O: 0.0050% or less, V: 0 to 0.05%, Nb: 0 to 0.010%, B: 0 to less than 0.0005%, Ca: 0 to 0.0100%, Mg: 0 to 0.0100%, and rare earth metal: 0 to 0.0100%, with the balance being Fe and impurities. In the steel material, the grain size number of prior-austenite grains is less than 7.0, Formula (1) to Formula (4) described in the specification are satisfied, the yield strength is 896 MPa or more, and the absorbed energy at -10° C. is 95 J or more.

公开(公告)号：US20220136469A1

公开(公告)日：2022-05-05

申请号：US17429404

申请日：2020-02-13

Applicant: NIPPON STEEL CORPORATION ,  USUI CO., LTD.

Inventor： Taizo MAKINO ,  Masahiro YAMAZAKI ,  Tomohiko OMURA ,  Yuji ARAI ,  Osamu ENDO ,  Naoki SERIZAWA ,  Tatsuya MASUDA

IPC: F02M37/00 ,  C22C38/02 ,  C22C38/00 ,  C22C38/06 ,  C22C38/50 ,  C22C38/48 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/58 ,  C21D8/10

Abstract: A steel pipe for a fuel injection pipe has a chemical composition consisting of, by mass %: C: 0.17 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.30 to 2.00%, P: 0.020% or less, S: 0.0100% or less, O: 0.0040% or less, Ca: 0.0010% or less, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, V: 0 to 0.15%, and the balance: Fe and impurities. The metal micro-structure consists substantially of tempered martensite, or tempered martensite and tempered bainite. The hardness is within the range of 350 to 460 HV1. A lattice spacing of a (211) diffraction plane measured by CoKα characteristic X-ray diffraction is 1.1716 Å or less, and a half-value width of the (211) diffraction plane is 1.200° or less. The number density of cementite having a diameter of 50 nm or more is 20/μm2 or less.

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：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.