公开(公告)号：US11773461B2

公开(公告)日：2023-10-03

申请号：US17059078

申请日：2019-04-25

Applicant: JFE STEEL CORPORATION

Inventor： Mami Endo ,  Yuichi Kamo ,  Masao Yuga

IPC: C21D9/08 ,  C21D1/18 ,  C21D6/00 ,  C21D8/10 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C22C38/54

CPC classification number: C21D9/085 ,  C21D1/18 ,  C21D6/004 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/105 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/52 ,  C22C38/54 ,  C21D2211/008

Abstract: A martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more, and excellent sulfide stress corrosion cracking resistance, and a method for manufacturing the same. The martensitic stainless steel seamless pipe has a composition that contains, by mass %, C: 0.010% or more, Si: 0.5% or less, Mn: 0.05 to 0.50%, P: 0.030% or less, S: 0.005% or less, Ni: 4.6 to 8.0%, Cr: 10.0 to 14.0%, Mo: 1.0 to 2.7%, Al: 0.1% or less, V: 0.005 to 0.2%, N: 0.1% or less, Ti: 0.255 to 0.500%, Cu: 0.01 to 1.0%, Co: 0.01 to 1.0%, and the balance being Fe and incidental impurities. C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti satisfy a predetermined relationship.

公开(公告)号：US11655526B2

公开(公告)日：2023-05-23

申请号：US16476970

申请日：2017-12-20

Applicant: JFE STEEL CORPORATION

Inventor： Kenichiro Eguchi ,  Masao Yuga

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

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

Abstract: A duplex stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The duplex stainless steel comprises, by mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, at least one selected from Al: 0.05 to 1.0%, Ti: 0.02 to 1.0%, and Nb: 0.02 to 1.0%, and the balance being Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

公开(公告)号：US11566301B2

公开(公告)日：2023-01-31

申请号：US16325572

申请日：2017-08-22

Applicant: JFE Steel Corporation

Inventor： Yusuke Yoshimura ,  Hiroki Ota ,  Masao Yuga ,  Yuichi Kamo ,  Kenichiro Eguchi

IPC: C21D9/08 ,  C21D6/00 ,  C22C38/60 ,  C22C38/52 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/10

Abstract: Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

公开(公告)号：US11313007B2

公开(公告)日：2022-04-26

申请号：US16333029

申请日：2017-09-13

Applicant: JFE Steel Corporation

Inventor： Masao Yuga ,  Mitsuhiro Okatsu

IPC: C21D6/02 ,  C21D8/10 ,  C21D9/08 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/32 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/54 ,  C22C38/20 ,  C22C38/28 ,  C22C38/42 ,  C22C38/50

Abstract: Provided herein is a high-strength seamless steel pipe containing a particular chemical composition. The volume fraction of tempered martensite is 90% or more in terms of a volume fraction. The number of nitride inclusions with a particle diameter of 4 μm or more is 50 or less per 100 mm2, the number of nitride inclusions with a particle diameter of less than 4 μm is 500 or less per 100 mm2, the number of oxide inclusions with a particle diameter of 4 μm or more is 40 or less per 100 mm2, and the number of oxide inclusions with a particle diameter of less than 4 μm is 400 or less per 100 mm2 in a cross section perpendicular to a rolling direction.

公开(公告)号：US11186885B2

公开(公告)日：2021-11-30

申请号：US16064086

申请日：2016-10-18

Applicant: JFE Steel Corporation

Inventor： Masao Yuga ,  Mitsuhiro Okatsu ,  Hiroki Ota

IPC: C21D8/10 ,  C22C38/32 ,  C22C38/54 ,  C21D9/08 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C21D1/18

Abstract: The high-strength seamless steel pipe has a volume fraction of tempered martensite of 95% or more, and a prior austenite size number of 8.5 or more, and contains nitride inclusions having a size of 4 μm or more and whose number is 100 or less per 100 mm2, nitride inclusions having a size of less than 4 μm and whose number is 700 or less per 100 mm2, oxide inclusions having a size of 4 μm or more and whose number is 60 or less per 100 mm2, and oxide inclusions having a size of less than 4 μm and whose number is 500 or less per 100 mm2, in a cross section perpendicular to a rolling direction.

公开(公告)号：US20210071275A1

公开(公告)日：2021-03-11

申请号：US16956805

申请日：2018-12-06

Applicant: JFE Steel Corporation

Inventor： Mitsuhiro Okatsu ,  Masao Yuga ,  Yoichi Ito

IPC: C21D8/10 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32

Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.25 to 0.50%, Si: 0.01 to 0.40%, Mn: 0.3 to 1.5%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.5 to 0.8%, Mo: 0.5 to 1.3%, Nb: 0.005 to 0.05%, B: 0.0005 to 0.0040%, Ca: 0.0010 to 0.0020%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 10 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 30 or less per 100 mm2.

公开(公告)号：US10300564B2

公开(公告)日：2019-05-28

申请号：US15129932

申请日：2015-03-31

Applicant: JFE STEEL CORPORATION

Inventor： Katsuyuki Ichimiya ,  Masao Yuga ,  Kazukuni Hase ,  Shigeru Endo

IPC: B23K35/30 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/14 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C21D9/18 ,  C21D9/30 ,  C21D9/50 ,  F16B5/08 ,  B23K9/23 ,  B23K9/18 ,  B23K103/04

Abstract: A weld joint with an excellent CTOD property is produced with a weld metal, using a steel plate as a base metal. The steel plate has a chemical composition including C: 0.03% to 0.09%, Si: 0.01% to 0.35%, Mn: 1.3% to 2.0%, P: 0.012% or less, S: 0.0035% or less, Al: 0.01% to 0.06%, Ni: less than 0.3%, Mo: less than 0.10%, Nb: 0.005% to 0.023%, Ti: 0.005% to 0.025%, B: less than 0.0003%, N: 0.002% to 0.005%, Ca: 0.0005% to 0.0050%, and O: 0.0030% or less, with the components additionally satisfying a predetermined relationship. The weld metal has a chemical composition including C: 0.040% to 0.090%, Si: 0.1% to 0.8%, Mn: 1.0% to 2.5%, Al: 0.020% or less, Ni: 0.1% to 1.0%, Mo: 0.05% to 0.50%, Ti: 0.005% to 0.050%, and B: 0.0015% or less, the balance being Fe and incidental impurities.

公开(公告)号：US20190048443A1

公开(公告)日：2019-02-14

申请号：US16078919

申请日：2016-11-18

Applicant: JFE Steel Corporation

Inventor： Mitsuhiro Okatsu ,  Masao Yuga ,  Hiroki Ota ,  Kazuki Fujimura

IPC: C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/20 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/08 ,  C21D8/10 ,  C21D6/00 ,  C21D6/02 ,  E21B17/00

Abstract: The steel pipe of the present invention is a low alloy high strength seamless steel pipe for oil country tubular goods including a composition containing, in terms of mass %, C: 0.23 to 0.27%, Si: 0.01 to 0.35%, Mn: 0.45 to 0.70%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.8 to 1.5%, Mo: 0.5 to 1.0%, Nb: 0.02 to 0.05%, B: 0.0015 to 0.0030%, Ti: 0.005 to 0.020%, and N: 0.005% or less, and having a value of a ratio of the Ti content to the N content (Ti/N) of 3.0 to 4.0, with the balance being Fe and inevitable impurities, the steel pipe having a ratio of a stress at a strain of 0.7% to a stress at a strain of 0.4% in a stress-strain curve; of 1.02 or less and a yield strength of 655 MPa or more.

公开(公告)号：US12157937B2

公开(公告)日：2024-12-03

申请号：US17296626

申请日：2019-11-01

Applicant: JFE Steel Corporation

Inventor： Shunsuke Sasaki ,  Tatsuro Katsumura ,  Hiroki Ota ,  Kazuki Fujimura ,  Masao Yuga

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

Abstract: Provided herein is a duplex stainless steel seamless pipe and a method for manufacturing the same. The duplex stainless steel seamless pipe has a composition comprising, in mass %, C: 0.005 to 0.08%, Si: 0.01 to 1.0%, Mn: 0.01 to 10.0%, Cr: 20 to 35%, Ni: 1 to 15%, Mo: 0.5 to 6.0%, N: 0.150 to less than 0.400%, and one, two or more selected from Ti: 0.0001 to 0.3%, Al: 0.0001 to 0.3%, V: 0.005 to 1.5%, Nb: 0.005 to less than 1.5%, and the balance being Fe and incidental impurities. The duplex stainless steel seamless pipe contains N, Ti, Al, V, and Nb so as to satisfy the following formula (1). The duplex stainless steel seamless pipe has an axial tensile yield strength of 757 MPa or more, and a ratio of 0.85 to 1.15 as a fraction of axial compressive yield strength to axial tensile yield strength. 0.150>N−(1.58Ti+2.70Al+1.58V+1.44Nb)  (1), wherein N, Ti, Al, V, and Nb represent the content of each element in mass %.

公开(公告)号：US20230128437A1

公开(公告)日：2023-04-27

申请号：US17913882

申请日：2021-03-25

Applicant: JFE Steel Corporation

Inventor： Kenichiro Eguchi ,  Masao Yuga

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

Abstract: A high-strength stainless steel seamless pipe for oil country tubular goods has a composition that comprises, in mass%, C : 0.002 to 0.05%, Si: 0.05 to 0.50%, Mn: 0.04 to 1.80%, P: 0.030% or less, S: 0.002% or less, Cr: more than 14.0% and 17.0% or less, Ni: 4.0 to 8.0%, Mo: 1.5 to 3.0%, Al: 0.005 to 0.10%, V : 0.005 to 0.20%, Co: 0.01 to 1.0%, N : 0.002 to 0.15%, and O: 0.006% or less, and that satisfies the predetermined formulae, and in which the balance is Fe and incidental impurities, the high-strength stainless steel seamless pipe having a microstructure containing prior austenite having an average grain size of 40 µm or less, the high-strength stainless steel seamless pipe having a yield strength of 758 MPa or more.