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公开(公告)号：US20230203632A1
公开(公告)日：2023-06-29
申请号：US18178888
申请日：2023-03-06
Applicant: NIPPON STEEL CORPORATION
Inventor： Kana JOTOKU , Kenta YAMADA , Hirokazu OKADA , Takahiro OSUKI
IPC: C22C38/58 , C22C38/00 , C22C38/02 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/52 , C22C38/54 , F16B5/08
CPC classification number: C22C38/58 , C22C38/001 , C22C38/002 , C22C38/02 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/52 , C22C38/54 , F16B5/08
Abstract: Provided is an austenitic stainless steel weld joint that is excellent in polythionic acid SCC resistance and naphthenic acid corrosion resistance, and is also excellent in creep ductility. An austenitic stainless steel weld joint includes a base material and a weld metal. The weld metal has a chemical composition at its width-center position and at its thickness-center position consisting of, in mass %, C: 0.050% or less, Si: 0.01 to 1.00%, Mn: 0.01 to 3.00%, P: 0.030% or less, S: 0.015% or less, Cr: 15.0 to 25.0%, Ni: 20.0 to 70.0%, Mo: 1.30 to 10.00%, Nb: 0.05 to 3.00%, N: 0.150% or less, and B: 0.0050% or less, with the balance: Fe and impurities.
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公开(公告)号：US20230212724A1
公开(公告)日：2023-07-06
申请号：US18001149
申请日：2021-06-23
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroyuki HIRATA , Shohgo AOTA , Mitsuru YOSHIZAWA , Takahiro OSUKI
IPC: C22C38/58 , C22C38/00 , C22C38/54 , C22C38/52 , C22C38/50 , C22C38/48 , C22C38/44 , C22C38/42 , C22C38/06 , C22C38/02 , C21D9/08 , C21D8/10
CPC classification number: C22C38/58 , C22C38/001 , C22C38/54 , C22C38/52 , C22C38/50 , C22C38/48 , C22C38/44 , C22C38/42 , C22C38/06 , C22C38/02 , C22C38/008 , C22C38/005 , C22C38/002 , C21D9/08 , C21D8/105 , F16L13/02
Abstract: There is provided a duplex stainless steel tube including a chemical composition consisting of, in mass %, C: 0.008 to 0.030%, Si: 0.10 to 0.70%, Mn: 0.80 to 2.60%, P: 0.030% or less, S: 0.0001 to 0.0050%, O: 0.0004 to 0.0150%, Sn: 0.0001% or more to less than 0.0100%, Cu: 0.10 to 2.50%, Ni: more than 2.50 to 5.50% or less, Cr: 21.5 to 25.5%, Mo: 0.10 to 0.50%, N: 0.050 to 0.200%, Al: 0.200% or less, and optional elements, with the balance: Fe and impurities, wherein 4S+8O+Sn is 0.0040 to 0.0900, and 4S+Sn is 0.0180 or less.
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公开(公告)号：US20240318289A1
公开(公告)日：2024-09-26
申请号：US18579095
申请日：2021-07-14
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroyuki HIRATA , Katsuki TANAKA , Masayuki TAKIGUCHI , Mitsuru YOSHIZAWA , Junichi HIGUCHI , Takahiro OSUKI
IPC: C22C38/54 , C21D1/18 , C21D1/28 , C21D6/00 , C21D8/00 , C22C38/00 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/52
CPC classification number: C22C38/54 , C21D1/18 , C21D1/28 , C21D6/004 , C21D6/005 , C21D6/007 , C21D6/008 , C21D8/005 , C22C38/001 , C22C38/002 , C22C38/005 , C22C38/008 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/52 , C21D2211/005
Abstract: Provided is a heat-resistant ferritic steel having a chemical composition containing, by mass %, C: 0.07 to 0.14%, Si: 0.15 to 0.35%, Mn: 0.30 to 0.55%, P: 0.0250% or less, S: 0.0030% or less, Ni: 0.15 to 0.35%, Cr: 8.0 to 9.7%, Mo: 0.20 to 0.60%, W: 1.50 to 2.30%, V: 0.16 to 0.25%, Nb: 0.020 to 0.120%, B: 0.0010 to 0.0050%, N: 0.010 to 0.080%, Al: 0.020% or less, and O: 0.020% or less, with the balance Fe and impurities, wherein VER, i.e., the V content (mass %) in precipitates obtained by extracted residue analysis satisfies [−0.2×C+0.060≤VER≤−0.1×C+0.160].
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公开(公告)号：US20230349027A1
公开(公告)日：2023-11-02
申请号：US18036699
申请日：2022-04-12
Inventor： Yukihiro NISHIDA , Shinji TSUGE , Takahiro OSUKI
IPC: C22C19/05
CPC classification number: C22C19/055
Abstract: A high-Ni alloy having excellent weld-hot-cracking resistance includes, in mass %, Cr: 16-30%, Ni: 18-50%, Al: 0.01-1.0%, and Ti: 0.01-1.5%. In a first aspect of the invention, a relationship between number density of TiC precipitates having 1.0 μm or more of equivalent circle diameter and Mg content in steel satisfies formula (1) below. In a second aspect of the invention, S average concentration in oxide- and sulfide-inclusions is 0.70 mass % or more. In a third aspect of the invention, mass ratios of CaO, MgO, and Al2O3 in inclusions, where O or S is detected, satisfy formula (2), the mass ratios being respectively calculated from average concentrations of Ca, Mg and Al in the inclusions, (1) number density of TiC (number of pieces/mm2)≤463−9.5×Mg concentration in steel (mass ppm) and (2) [CaO−0.6×MgO] (mass %)/[CaO+MgO+Al2O3] (mass %)≥0.20.
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公开(公告)号：US20230220508A1
公开(公告)日：2023-07-13
申请号：US17996700
申请日：2021-04-21
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroyuki HIRATA , Masahiro SETO , Mitsuru YOSHIZAWA , Junichi HIGUCHI , Takahiro OSUKI
IPC: C21D6/00 , C22C38/54 , C22C38/52 , C22C38/50 , C22C38/48 , C22C38/44 , C22C38/42 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00 , C22C38/46
CPC classification number: C21D6/004 , C21D6/005 , C21D6/008 , 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 , C22C38/46 , C21D2211/001
Abstract: A method for producing an austenitic heat resistant steel in which a difference between a content of Nb and an amount of Nb analyzed as extraction residues satisfies [0.170≤Nb−NbER≤0.480], the method including: a forming step of machining and forming a steel having a predetermined chemical composition into a product shape; a solution heat treatment step of performing, after the forming step, heat treatment under conditions including a heat treatment temperature satisfying [−250Nb+1200≤T≤−100Nb+1290] and a soaking time satisfying [405−0.3T≤t≤2475−1.5T]; and a cooling step of performing cooling after the solution heat treatment step.
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公开(公告)号：US20230203629A1
公开(公告)日：2023-06-29
申请号：US17996543
申请日：2021-04-21
Applicant: NIPPON STEEL CORPORATION
Inventor： Masahiro SETO , Hiroyuki HIRATA , Mitsuru YOSHIZAWA , Junichi HIGUCHI , Takahiro OSUKI
IPC: C22C38/48 , C22C38/54 , C22C38/52 , C22C38/50 , C22C38/46 , C22C38/44 , C22C38/42 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00 , C22C33/04 , C21D8/02 , C21D6/00 , C21D1/84
CPC classification number: C22C38/48 , C22C38/54 , C22C38/52 , C22C38/50 , C22C38/46 , C22C38/44 , C22C38/42 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/008 , C22C38/005 , C22C38/002 , C22C38/001 , C22C33/04 , C21D8/0205 , C21D8/0226 , C21D8/0236 , C21D8/0263 , C21D6/004 , C21D6/005 , C21D6/007 , C21D6/008 , C21D1/84 , C21D2211/001
Abstract: There is provided an austenitic heat resistant steel including a chemical composition that consists of, in mass %, C: 0.04 to 0.12%, Si: 0.01 to 0.30%, Mn: 0.50 to 1.50%, P: 0.001 to 0.040%, S: less than 0.0050%, Cu: 2.2 to 3.8%, Ni: 8.0 to 11.0%, Cr: 17.7 to 19.3%, Mo: 0.01 to 0.55%, Nb: 0.400 to 0.650%, B: 0.0010 to 0.0060%, N: 0.050 to 0.160%, Al: 0.025% or less, and O: 0.020% or less, with the balance: Fe and impurities and that satisfies [0.170≤Nb−NbER≤0.480].
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公开(公告)号：US20200332378A1
公开(公告)日：2020-10-22
申请号：US16759798
申请日：2018-11-14
Applicant: NIPPON STEEL CORPORATION
Inventor： Masayuki SAGARA , Yusaku TOMIO , Takahiro OSUKI , Yusuke UGAWA
IPC: C21D8/00 , C22C38/54 , C22C38/46 , C22C38/44 , C22C38/42 , C22C38/04 , C22C38/06 , C22C38/02 , C22C38/00 , C21D6/00
Abstract: A duplex stainless steel with occurrence of pitting suppressed is provided. A duplex stainless steel according to the present disclosure has a chemical composition consisting of, in mass %, Cr: more than 27.00% to 29.00%, Mo: 2.50 to 3.50%, Ni: 5.00 to 8.00%, W: 4.00 to 6.00%, Cu: 0.01 to less than 0.10%, N: more than 0.400% to 0.600%, C: 0.030% or less, Si: 1.00% or less, Mn 1.00% or less, sol.Al: 0.040% or less, V: 0.50% or less, O: 0.010% or less, P: 0.030% or less, and S: 0.020% or less with the balance being Fe and impurities and satisfying Formula (1), a microstructure consisting of 35 to 65 volume % of ferrite phase with the balance being the austenite phase, and the area fraction of Cu precipitated in the ferrite phase is 0.5% or less. Cr+4.0×Mo+2.0×W+20×N−5×ln(Cu)≥65.2 (1)
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公开(公告)号：US20240240295A1
公开(公告)日：2024-07-18
申请号：US18249779
申请日：2021-08-06
Applicant: NIPPON STEEL CORPORATION
Inventor： Hiroyuki HIRATA , Mitsuru YOSHIZAWA , Katsuki TANAKA , Takahiro OSUKI
IPC: C22C38/58 , C22C30/02 , C22C30/04 , C22C38/00 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/10 , C22C38/12 , C22C38/16 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/52 , C22C38/54
CPC classification number: C22C38/58 , C22C30/02 , C22C30/04 , C22C38/001 , C22C38/002 , C22C38/005 , C22C38/008 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/10 , C22C38/12 , C22C38/16 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/52 , C22C38/54
Abstract: A composite tube is provided that includes a first tube and a second tube. A chemical composition of the first tube includes, in mass %, C: more than 0.060% to 0.400% or less, Si: 0.01 to 1.00%, Mn: 0.01 to 1.20%, P: 0.0350% or less, S: 0.0150% or less, Sn: 0.0005 to 0.0400%, Al: 0.040% or less, N: 0.050% or less, O: 0.030% or less, and the balance: Fe and impurities. A chemical composition of the second tube includes, in mass %, C: 0.003 to 0.100%, Si: 0.01 to 1.50%, Mn: 0.01 to 2.20%, P: 0.0400% or less, S: 0.0100% or less, Sn: 0.0005 to 0.0300%, Ni: 7.0 to 52.0%, Cr: 15.0 to 27.0%, Al: 0.001 to 0.600%, N: 0.001 to 0.150%, O: 0.030% or less, and the balance: Fe and impurities. The composite tube satisfies formulas [Siave+6×Pave+20×Save+2×Snave≤1.1000] and [0.0015≤4×Save+Snave].
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公开(公告)号：US20240175113A1
公开(公告)日：2024-05-30
申请号：US18552084
申请日：2022-03-30
Applicant: NIPPON STEEL CORPORATION
Inventor： Takahiro OSUKI , Shohgo AOTA , Takahiro IZAWA , Shinnosuke KURIHARA
IPC: C22C38/54 , B23K31/02 , B23K35/30 , B23K101/04 , B23K103/04 , C22C38/00 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/52
CPC classification number: C22C38/54 , B23K35/3086 , C22C38/001 , C22C38/002 , C22C38/008 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/52 , B23K31/027 , B23K2101/04 , B23K2103/05
Abstract: A duplex stainless steel welded joint is provided that can suppress undercuts and is excellent in fatigue characteristics. The duplex stainless steel welded joint includes a base metal, and a weld metal consisting of, in mass %, C: 0.001% to 0.030%, Si: 0.05% to 0.70%, Mn: 0.05% to 0.85%, P: 0.030% or less, S: 0.0030% or less, Cr: 21.00% to 28.00%, Ni: 5.00% to 11.00%, Mo: 2.00% to 4.50%, Cu: 0.01 to 4.00%, sol. Al: 0.0010 to 0.0500%, N: 0.080% to 0.400%, and B: 0.0001 to 0.0100%, with the balance being Fe and impurities, and satisfies the content of each element in the base metal and the weld metal, and also satisfies Formula (1) and Formula (2).
Si+3Mn≤3.00 (1)
0
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公开(公告)号：US20220411908A1
公开(公告)日：2022-12-29
申请号：US17757126
申请日：2021-01-08
Applicant: NIPPON STEEL CORPORATION
Inventor： Takahiro OSUKI , Shinnosuke KURIHARA , Kana JOTOKU , Yuhei SUZUKI , Shohgo AOTA
Abstract: An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.
