公开(公告)号：US20230175107A1

公开(公告)日：2023-06-08

申请号：US17906664

申请日：2020-04-01

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yusaku TOMIO

IPC: C22C38/54 ,  C22C38/00 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C21D9/08

CPC classification number: C22C38/54 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C21D9/08

Abstract: The steel material of the present disclosure includes a chemical composition consisting of, in mass %, C: 0.035% or less, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.0050% or less, sol. Al: 0.005 to 0.100%, N: 0.001 to 0.020%, Ni: 5.00 to 7.00%, Cr: 10.00 to 14.00%, Cu: 1.50 to 3.50%, Mo: 1.00 to 4.00%, V: 0.01 to 1.00%, Ti: 0.02 to 0.30%, Co: 0.01 to 0.50%, Ca: 0.0003 to 0.0030%, O: 0.0050% or less, W: 0 to 1.50%, Nb: 0 to 0.50%, B: 0 to 0.0050%, Mg: 0 to 0.0050%, and rare earth metals (REM): 0 to 0.020%, with the balance being Fe and impurities, in which a total number density of Mn sulfide having an equivalent circular diameter of 1.0 μm or more and Ca sulfide having an equivalent circular diameter of 2.0 μm or more is 0.50 pieces/mm2 or less.

公开(公告)号：US20210238705A1

公开(公告)日：2021-08-05

申请号：US16973231

申请日：2019-09-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yusaku TOMIO

IPC: C21D9/46 ,  C22C38/52 ,  C22C38/50 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18

Abstract: The martensitic stainless steel material has a chemical composition, which contains: in mass %, C: 0.030% or less, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.005% or less, Al: 0.010 to 0.100%, N: 0.0010 to 0.0100%, Ni: 5.00 to 6.50%, Cr: 10.00 to 13.40%, Cu: 1.80 to 3.50%, Mo: 1.00 to 4.00%, V: 0.01 to 1.00%, Ti: 0.050 to 0.300%, Co: 0.300% or less, Ca: 0.0006 to 0.0030%, and O: 0.0050% or less, and satisfies Formulae (1) and (2) in the description. An area of each intermetallic compound and each Cr oxide in the steel material is 5.0 μm2 or less, a total area fraction of intermetallic compounds and Cr oxides is 3.0% or less, and a maximum circle-equivalent diameter of Ca oxide is 9.5 μm or less.

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：US20210269904A1

公开(公告)日：2021-09-02

申请号：US17253222

申请日：2019-07-09

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yusaku TOMIO

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

Abstract: The chemical composition of the seamless steel pipe contains Cr 15.00 to 18.00% in mass % and satisfies Formulae (1) and (2). Furthermore, in the microstructure, (I) a total volume ratio of ferrite and martensite is 80% or more, with the balance being retained austenite of a volume ratio of 20% or less, (II) the number of intersections NTL in the L-direction observation field of view is 38 or more and NTL/NL is 1.80 or more, and further (III) the number of intersections NTC in the C-direction observation field of view is 30 or more and NTC/NC is 1.70 or more. 156Al+18Ti+12Nb+11Mn+5V+328.125N+243.75C+12.5S≤12.5  (1) Ca/S≥≥4.0  (2)

公开(公告)号：US20250137110A1

公开(公告)日：2025-05-01

申请号：US18691204

申请日：2022-09-29

Applicant: NIPPON STEEL CORPORATION

Inventor： Seiya OKADA ,  Yuji ARAI ,  Daisuke MATSUO

IPC: C22C38/60 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C22C38/54 ,  C22C38/58 ,  F16L9/02

Abstract: The duplex stainless steel pipe according to the present disclosure consists of, by mass %, C: 0.030% or less, Si: 1.00% or less, Mn: 0.10 to 7.00%, P: 0.040% or less, S: 0.0050% or less, Cr: 20.0 to 30.0%, Ni: 4.2 to 10.0%, Mo: 0.5 to 5.0%, Cu: 0.5 to 6.0%, N: less than 0.350%, O: 0.0005 to 0.0100%, and Ca: 0.0005 to 0.0100%, with the balance being Fe and impurities. A microstructure consists of, in volume ratio, ferrite in an amount of 30 to 80% with the balance being austenite. A yield strength is 552 MPa or more. A number density of Ca oxides having an equivalent circular diameter of 2.0 μm or more is 500/100 mm2 or more.

公开(公告)号：US20230392241A1

公开(公告)日：2023-12-07

申请号：US18245773

申请日：2021-10-07

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yusaku TOMIO

IPC: C22C38/44 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/08 ,  C21D8/10 ,  C21D6/00

CPC classification number: C22C38/44 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/005 ,  C22C38/004 ,  C22C38/002 ,  C22C38/001 ,  C21D9/085 ,  C21D8/105 ,  C21D6/004 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D2211/008

Abstract: A martensitic stainless steel material according to the present disclosure contains, in mass %, C: 0.030% or less, Ni: 5.05 to 7.50%, Cr: 10.00 to 14.00%, and Mo: 1.50 to 3.50%, and has a yield strength of 758 MPa or more, and on two line segments LS of 1000 μm extending in a wall thickness direction with arbitrary two points as a center located at positions at a depth of 2 mm from the inner surface, a degree of Cr segregation ΔCr defined by Formula (1) and a degree of Mo segregation ΔMo defined by Formula (2) satisfy Formula (3):


ΔCr=([Cr*]max−[Cr*]min)/[Cr*]ave  (1)



ΔMo=([Mo*]max−[Mo*]min)/[Mo*]ave  (2)



ΔCr+ΔMo≤0.59  (3).

公开(公告)号：US20230212723A1

公开(公告)日：2023-07-06

申请号：US17995636

申请日：2021-04-28

Applicant: NIPPON STEEL CORPORATION

Inventor： Mikiko NOGUCHI ,  Jun NAKAMURA ,  Masayuki SAGARA ,  Daisuke MATSUO ,  Yoshihei WAKINO

IPC: C22C38/58 ,  F16L9/02 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

CPC classification number: C22C38/58 ,  F16L9/02 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/008 ,  C22C38/005 ,  C22C38/002 ,  C22C38/001

Abstract: The duplex stainless steel seamless pipe according to the present disclosure has the chemical composition described in the description and a microstructure consisting of 30 to 55% of ferrite, and austenite. In a square observation field of view region with sides of 250 μm including a center portion of the wall thickness and including a T direction and a C direction, a number of intersections NT which is a number of intersections between the line segment T1 to T4 described in the description and ferrite interfaces is 65 or more. A number of intersections NC which is a number of intersections between the line segments C1 to C4 described in the description and ferrite interfaces is 50 or more.

公开(公告)号：US20240401722A1

公开(公告)日：2024-12-05

申请号：US18693251

申请日：2022-09-29

Applicant: NIPPON STEEL CORPORATION

Inventor： Toshiya NISHIMURA ,  Daisuke MATSUO ,  Kyohei KANKI

IPC: F16L9/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/50 ,  C22C38/52

Abstract: A martensitic stainless steel pipe according to the present disclosure consists of, in mass %, C: less than 0.030%, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.0010 to 0.0050%, Cr: 10.00 to 14.00%, Ni: 5.00 to 7.50%, Mo: 1.10 to 3.50%, Cu: 1.00 to 3.50%, Al: 0.005 to 0.050%, N: 0.0030 to 0.0500%, V: 0.01 to 0.30%, Ti: 0.020 to 0.150%, Co: 0.01 to 0.50%, Ca: 0.0010 to 0.0050%, and the balance: Fe and impurities. The yield strength is 758 MPa or more. A number density of Ca sulfides having an equivalent circular diameter of 1.0 μm or more is 3/mm2 or more.

公开(公告)号：US20240018636A1

公开(公告)日：2024-01-18

申请号：US18255393

申请日：2021-01-28

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke MATSUO ,  Yusaku TOMIO

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

CPC classification number: C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/005 ,  C22C38/002 ,  C22C38/001

Abstract: The steel material of the present disclosure includes a chemical composition consisting of, in mass %, C: 0.035% or less, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.0050% or less, sol. Al: 0.005 to 0.100%, N: 0.001 to 0.020%, Ni: 5.00 to 7.50%, Cr: 10.00 to 14.00%, Cu: 0.01 to less than 1.50%, Mo: 1.50 to 3.50%, V: 0.01 to 1.00%, Ti: 0.02 to 0.30%, Co: 0.01 to 0.50%, Ca: 0.0003 to 0.0030%, 0: 0.0050% or less, W: 0 to 1.50%, Nb: 0 to 0.50%, B: 0 to 0.0050%, Mg: 0 to 0.0050%, and rare earth metals (REM): 0 to 0.020%, with the balance being Fe and impurities, in which a total number density of Mn sulfide having an equivalent circular diameter of 1.0 μm or more and Ca sulfide having an equivalent circular diameter of 2.0 μm or more is 0.50/mm2 or less.

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).