公开(公告)号：US11834725B2

公开(公告)日：2023-12-05

申请号：US16973231

申请日：2019-09-26

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke Matsuo ,  Yusaku Tomio

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

CPC classification number: C21D9/46 ,  C21D1/18 ,  C21D6/004 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/50 ,  C22C38/52 ,  C21D2211/008

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：US11970759B2

公开(公告)日：2024-04-30

申请号：US17277794

申请日：2019-10-01

Applicant: NIPPON STEEL CORPORATION

Inventor： Kyohei Kanki ,  Masayuki Sagara ,  Yusaku Tomio ,  Daisuke Matsuo

IPC: C22C38/52 ,  C21D6/00 ,  C21D8/10 ,  C21D9/14 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/22 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50

CPC classification number: C22C38/52 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/105 ,  C21D9/14 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C21D2211/008

Abstract: The seamless steel pipe according to the present disclosure includes a chemical composition consisting of, in mass %, C: 0.030% or less, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.0050% or less, Al: 0.001 to 0.100%, N: 0.0500% or less, O: 0.050% or less, Ni: 5.00 to 6.50%, Cr: more than 10.00 to 13.40%, Cu: more than 1.50 to 3.50%, Mo: 1.00 to 4.00%, V: 0.01 to 1.00%, Ti: 0.050 to 0.300%, and Co: 0.010 to 0.300%, with the balance being Fe and impurities, and satisfying Formula (1), wherein a depassivation pH of an inner surface is 3.00 or less.

Cr+2.0 Mo+0.5 Ni+2.0 Cu+0.5 Co≥20.0  (1)

公开(公告)号：US12043885B2

公开(公告)日：2024-07-23

申请号：US17253222

申请日：2019-07-09

Applicant: NIPPON STEEL CORPORATION

Inventor： Daisuke Matsuo ,  Yusaku Tomio

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

CPC classification number: C22C38/50 ,  C21D8/005 ,  C21D8/065 ,  C21D9/085 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008

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：US11286545B2

公开(公告)日：2022-03-29

申请号：US16962299

申请日：2019-01-17

Applicant: NIPPON STEEL CORPORATION

Inventor： Akiko Tomio ,  Masaki Ueyama ,  Yusaku Tomio

IPC: C22C30/02 ,  C22F1/16

Abstract: A Cr—Ni alloy having high yield strength and high resistance to sulfuric acid general corrosion at a high temperature of 250° C. is provided. The Cr—Ni alloy has a chemical composition consisting of, in mass %, Si: 0.01 to 0.50%, Mn: 0.01 to 1.00%, Cr: 21.0 to 27.0%, Ni: 40.0 to less than 50.0%, Mo: 4.5 to less than 9.0%, W: 2.0 to 6.0%, Cu: more than 2.0% and not more than 6.0%, Co: 0.01 to 2.00%, one or two kinds selected from the group consisting of Ca and Mg: 0.001 to 0.010% in total, sol. Al: 0.005 to 0.200%, N: 0.01 to 0.20%, and the balance being Fe and impurities. The dislocation density in the Cr—Ni alloy satisfies the following Formula (1): 8.00×1014≤ρ≤2.50×1015+1.40×1014×[Cu+Co]  (1)

公开(公告)号：US11965232B2

公开(公告)日：2024-04-23

申请号：US17278742

申请日：2019-10-01

Applicant: NIPPON STEEL CORPORATION

Inventor： Kyohei Kanki ,  Masayuki Sagara ,  Yusaku Tomio

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

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

Abstract: The seamless steel pipe according to the present disclosure includes a chemical composition consisting of, in mass %, C: 0.030% or less, Si: 1.00% or less, Mn: 1.00% or less, P: 0.030% or less, S: 0.0050% or less, Al: 0.001 to 0.100%, N: 0.0500% or less, O: 0.050% or less, Ni: 3.00 to 6.50%, Cr: more than 10.00 to 13.40%, Mo: 0.50 to 4.00%, V: 0.01 to 1.00%, Ti: 0.010 to 0.300%, and Co: 0.010 to 0.300%, with the balance being Fe and impurities, and satisfying Formula (1), and a microstructure containing, in volume ratio, 80.0% or more of martensite, wherein a depassivation pH of an inner surface is 3.50 or less.

Cr+2.0Mo+0.5Ni+0.5Co≥16.0  (1)

公开(公告)号：US11807910B2

公开(公告)日：2023-11-07

申请号：US16617765

申请日：2018-06-08

Applicant: Nippon Steel Corporation

Inventor： Masaki Ueyama ,  Yusaku Tomio ,  Yuhei Suzuki

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

CPC classification number: C21D9/08 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/105 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/48 ,  C22C38/50 ,  C21D2211/001

Abstract: Provided is an austenitic alloy pipe, which has high yield strength, excellent SCC resistance, suppressed strength anisotropy, and high detectability in ultrasonic flaw detection. The austenitic alloy pipe according to the present embodiment has a chemical composition consisting of: in mass %, C: 0.004 to 0.030%, Si: 1.00% or less, Mn: 0.30 to 2.00%, P: 0.030 or less, S: 0.0020% or less, Al: 0.001 to 0.100%, Cu: 0.50 to 1.50%, Ni: 25.00 to 55.00%, Cr: 20.00 to 30.00%, Mo: 2.00 to 10.00%, and N: 0.005 to 0.100%, with the balance being Fe and impurities. A grain size number of austenite crystal grain is 2.0 to 7.0 and a mixed grain ratio is not more than 5%. Tensile YS is not less than 758 MPa, compressive YS/tensile YS is 0.85 to 1.10, and an outer diameter is not less than 170 mm.