Patents Assigned to NIPPON STEEL Stainless Steel Corporation
  • Publication number: 20210230725
    Abstract: Austenitic stainless steel sheet excellent in high-temperature fatigue characteristics able to be applied to exhaust manifolds and turbo exhaust pipes of automobiles and other parts subjected to vibration at 400° C. to 600° C. temperatures is provided, specifically, austenitic stainless steel sheet excellent in high-temperature fatigue characteristics comprising, by mass %, C: 0.002 to 0.3%, Si: 1.0 to 4.0%, Mn: 0.05 to 3.0%, P: 0.01 to 0.05%, S: 0.0001 to 0.01%, Ni: 5 to 15%, Cr: 15 to 30%, Mo: 0.5 to 4.0%, and N: 0.01 to 0.3%, having a balance of Fe and unavoidable impurities, satisfying Si+Mo?1.8%, and satisfying A+B>2.5 mm/mm2 prescribing the grain boundary lengths.
    Type: Application
    Filed: October 30, 2019
    Publication date: July 29, 2021
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Chikako YOSHII, Junichi HAMADA
  • Publication number: 20210140569
    Abstract: This ferritic stainless steel pipe contains, by mass %: C: 0.001% to 0.100%; Si: 0.01% to 2.00%; Mn: 0.01% to 2.00%; P: 0.001% to 0.05%; S: 0.0001% to 0.005%; Cr: 10.5% to 20.0%; Sn: 0.001% to 0.600%; Ti: 0.001% to 1.000%; Al: 0.001% to 0.100%; and N: 0.001% to 0.02%, with a balance being Fe and unavoidable impurities, the ferritic stainless steel pipe includes a pipe-end-thickened portion at a pipe end portion, and a gap distance d (?un) formed at the pipe end portion satisfies a relationship of d?Cr2/(1000 Sn) (in the expression, Cr and Sn represent amounts (mass %) of respective elements).
    Type: Application
    Filed: March 27, 2018
    Publication date: May 13, 2021
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Masatoshi ABE, Junichi HAMADA, Nobuhiko HIRAIDE
  • Patent number: 10995888
    Abstract: A Ti-containing ferritic stainless steel sheet for an exhaust pipe flange member has a composition containing, in mass percentage, from 0.003 to 0.030% of C, 2.0% or less of S i, 2.0% or less of Mn, 0.050% or less of P, 0.040% or less of S, from 10.0 to 19.0% of Cr, 0.030% or less of N, from 0.07 to 0.50% of Ti, from 0.010 to 0.20% of Al, from 0 to 1.50% of Mo, and from 0 to 0.0030% of B, with the balance Fe and unavoidable impurities, has a K value of 150 or more, has a sheet surface hardness of 170 HV or less, and has a sheet thickness of from 5.0 to 11.0 mm. The K value equals ?0.07×Cr?6790×Free(C+N)?1.44×d+267, wherein Free(C+N) corresponds to the solid-dissolved (C+N) concentration (% by mass), and d represents an average crystal grain diameter (?m).
    Type: Grant
    Filed: February 7, 2017
    Date of Patent: May 4, 2021
    Assignee: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Seiji Mitsunaga, Nobuhisa Ebihama, Yasuhiro Ehara, Kazunari Imakawa
  • Publication number: 20210115543
    Abstract: A stainless steel material including a base material made of ferritic stainless steel, a Cr oxide layer formed on a surface of the base material, and a spinel oxide layer formed on a surface of the Cr oxide layer, wherein a chemical composition of the base material satisfies [16.0?Cr+3×Mo?2.5×B?17×C?3?Si?35.0], a thickness of the Cr oxide layer (TCr) and a thickness of the spinel oxide layer (TS) satisfy [0.55?TCr/TS?6.7], the base material contains precipitate including one or more kinds selected from a M23C6, a M2B, a complex precipitate in which M2B acts as a precipitation nucleus, and M23C6 precipitates on a surface of the M2B, and a complex precipitate in which NbC acts as a precipitation nucleus, and M23C6 precipitates on a surface of the NbC, and a part of the precipitate protrude from the surface of the Cr oxide layer.
    Type: Application
    Filed: March 27, 2018
    Publication date: April 22, 2021
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Takumi NISHIMOTO, Yoshio TARUTANI
  • Publication number: 20210108297
    Abstract: The present invention has as its object to expand applications to types of steel having corrosion resistances of SUS 329J1 or more and has as its challenge to obtain duplex stainless steel which has excellent corrosion resistance in an environment with a high chloride ion concentration close to brackish water or seawater and having a high economicalness. The inventors discovered that by reducing Mn to less than 2.0% and N to 0.25% or less, then adding a trace amount of Nb, the effect of raising the critical pitting temperature CPT is easily obtained. Further, they heated steel to which a trace amount of Nb was added for solution heat treatment, then examined the effects on the precipitation of Cr nitrides and Nb nitrides and developed duplex stainless steel raised in pitting resistance of the matrix material. That is, by slow cooling down to 800° C.
    Type: Application
    Filed: March 30, 2018
    Publication date: April 15, 2021
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Shinji TSUGE, Yuusuke OIKAWA
  • Publication number: 20210040590
    Abstract: This ferritic stainless steel includes: in terms of % by mass, C: 0.001% to 0.100%; Si: 0.01% to 5.00%; Mn: 0.01% to 2.00%; P: 0.050% or less; S: 0.0100% or less; Cr: 9.0% to 25.0%; Ti: 0.001% to 1.00%; Al: 0.001% to 5.000%; and N: 0.001% to 0.050%, with a balance being Fe and impurities, wherein in a region from a steel surface to a depth of 5 nm, and not exceeding a thickness of a passive film, a total amount of Al and Si is 1.0 atomic % or more, an amount of Cr is 10.0 atomic % or more, and an amount of Fe is 85.0 atomic % or less, in terms of cation fraction.
    Type: Application
    Filed: March 19, 2019
    Publication date: February 11, 2021
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Masatoshi ABE, Junichi HAMADA, Nobuhiko HIRAIDE, Atsutaka HAYASHI
  • Publication number: 20210032718
    Abstract: A ferritic stainless steel sheet is provided that has a chemical composition consisting of, in mass %, C: 0.001 to 0.020%, Si: 0.02 to 1.50%, Mn: 0.02 to 1.50%, P: 0.01 to 0.05%, S: 0.0001 to 0.01%, Cr: 10.0 to 25.0%, Ti: 0.01 to 0.30%, N: 0.001 to 0.030%, and optional elements, with the balance being Fe and unavoidable impurities, wherein: a grain size number is 6 or more; the ferritic stainless steel sheet satisfies the formulas [A+B?12.0/t], [X+Y?12.0/(t?0.3)] and [(X+Y)?(A+B)?5.0] with respect to crystal orientation intensities of a ferrite phase obtained by X-ray diffraction; and the sheet thickness is 1.0 mm or more.
    Type: Application
    Filed: March 29, 2019
    Publication date: February 4, 2021
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Koh NISHIMURA, Yoshiharu INOUE, Junichi HAMADA
  • Publication number: 20210025022
    Abstract: Ferritic stainless steel is characterized by including, by mass %: Cr: 12.0% to 16.0%; C: 0.020% or less; Si: 2.50% or less; Mn: 1.00% or less; P: 0.050% or less; S: 0.0030% or less; Al: 2.50% or less; N: 0.030% or less; Nb: 0.001% to 1.00%; one or more of B: 0.0200% or less, Sn: 0.20% or less, Ga: 0.0200% or less, Mg: 0.0200% or less, and Ca: 0.0100% or less; and a balance consisting of Fe and impurities, in which Expression (1) is satisfied. 10(B+Ga)+Sn+Mg+Ca >0.
    Type: Application
    Filed: March 26, 2019
    Publication date: January 28, 2021
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Masaharu HATANO, Mitsuki SUGEOI, Takumi NISHIMOTO
  • Publication number: 20210010119
    Abstract: Ferritic stainless steel securing corrosion resistance while being excellent in ridging resistance able to be stably provided, that is, ferritic stainless steel with excellent ridging resistance having a composition comprising, by mass %, C: 0.001 to 0.01%, Si: 0.3% or less, Mn: 0.3% or less, P: 0.04% or less, S: 0.01% or less, Cr: 10 to 21%, Al: 0.01 to 0.2%, Ti: 0.015 to 0.3%, 0: 0.0005 to 0.0050%, N: 0.001 to 0.02%, Ca: 0.0015% or less, and Mg: 0.0003% to 0.
    Type: Application
    Filed: March 29, 2019
    Publication date: January 14, 2021
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Shigeru KANEKO, Katsuhiro FUCHIGAMI, Yoshiharu INOUE
  • Patent number: 10807156
    Abstract: A method for producing an austenitic stainless steel slab by continuous casting of an austenitic stainless steel, including applying electric power to the molten steel in a depth region providing a solidification shell thickness of from 5 to 10 mm at least at a center position in the long edge direction, so as to cause flows in directions inverse to each other in the long edge direction on both long edge sides, thereby performing electro-magnetic stirring (EMS) to control a continuous casting condition satisfying 10<?T<50×FEMS+10. Herein, ?T represents a difference between an average molten steel temperature (° C.) and a solidification starting temperature (° C.) of the molten steel, and FEMS represents a stirring intensity index shown by a function of a molten steel flow velocity in the long edge direction imparted by the electro-magnetic stirring and a casting velocity.
    Type: Grant
    Filed: March 14, 2018
    Date of Patent: October 20, 2020
    Assignee: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Yasuhiro Ehara, Shun Saito, Kazunari Morita, Hiroshi Morikawa
  • Publication number: 20200283867
    Abstract: Provided are a stainless steel sheet with good corrosion resistance, low contact resistance and good press workability without the use of expensive materials such as gold or rare metals, and a method of manufacture the same. A method of manufacturing a stainless steel sheet includes: preparing a slab having a chemical composition including, in mass %: 20 to 26% Cr, up to 0.1% N, up to 2.0% Si, etc. (step S1); performing hot rolling and cold rolling on the slab to produce a rolled steel sheet with a thickness of 50 to 200 ?m (step S2); an annealing step in which the rolled steel sheet is annealed and cooled in a gas atmosphere containing nitrogen (step S3); and pickling the rolled steel sheet after the annealing step with a solution containing a non-oxidizing acid (step S4). The stainless steel sheet has an N content of 0.6 to 2.0% by mass.
    Type: Application
    Filed: September 19, 2017
    Publication date: September 10, 2020
    Applicant: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Hideya KAMINAKA, Yoshitaka NISHIYAMA, Koichi NOSE, Jun MAKI, Junko IMAMURA, Kohei MAEJIMA, Yuya TAKASHIMA
  • Patent number: 10751791
    Abstract: A continuous casting method includes discharging a molten steel from discharge ports of a submerged nozzle under conditions (A) and (B); and performing electro-magnetic stirrer (EMS) to cause flows in directions inverse to each other in the long edge direction on both long edge sides in the molten steel in a region having a depth providing a thickness of a solidification shell of from 5 to 10 mm at least at a center position in the long edge direction. (A) a discharge extended line from the discharge port of the submerged nozzle intersects a molten steel surface in the mold at a point P, and the position of the point P satisfies 0.15?M/W?0.45; and (B) a condition satisfying 0?L?0.17Vi?350, wherein the unit for L is mm, and Vi represents a discharge velocity (mm/s) of the molten steel at the outlet opening.
    Type: Grant
    Filed: September 16, 2016
    Date of Patent: August 25, 2020
    Assignee: NIPPON STEEL STAINLESS STEEL CORPORATION
    Inventors: Yasuhiro Ehara, Shun Saito, Kazunari Morita, Hiroshi Morikawa
  • Publication number: 20200255919
    Abstract: The hot-rolled Nb-containing ferritic stainless steel sheet of the present invention has a composition containing C: 0.030 mass % or less, Si: 2.00 mass % or less, Mn: 2.00 mass % or less, P: 0.050 mass % or less, S: 0.040 mass % or less, Cr: 10.00 mass % to 25.00 mass %, N: 0.030 mass % or less and Nb: 0.01 mass % to 0.80 mass %, with the balance being made up of Fe and unavoidable impurities. In this hot-rolled Nb-containing ferritic stainless steel sheet, the precipitation amount of Nb carbonitrides is 0.2 mass % or more, and the number of Laves phases having a grain size of 0.1 ?m or less is 10 or fewer per 10 ?m2 of surface area.
    Type: Application
    Filed: April 10, 2020
    Publication date: August 13, 2020
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Yutaka YAKUSHIJIN, Akira HIRONAKA, Kazunari IMAKAWA
  • Publication number: 20200131610
    Abstract: This austenitic stainless steel contains, by mass %: C: 0.3% or less, Si: 0.1% to 1.5%, Mn: 5.5% to 20%, P: 0.050% or less, S: 0.005% or less, Cr: 10% to 20%, Ni: 4.0% to 12%, N: 0.40% or less, Cu: 4.0% or less, O: 0.02% or less, and either one or both of Ca: 0.01% or less and Al: 0.3% or less, with a remainder being Fe and inevitable impurities, and the following Formula (1) is satisfied. [Ni]+[Cu]+12.93[C]+1.11[Mn]+0.72[Cr]+0.88[Mo]?0.27[Si]+7.55[N]?29.
    Type: Application
    Filed: March 20, 2018
    Publication date: April 30, 2020
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Kazuhisa MATSUMOTO, Masaharu HATANO, Jun NAKAMURA
  • Publication number: 20200024682
    Abstract: This ferritic stainless steel sheet contains, by mass %: C: 0.001% to 0.020%; Si: 0.01% to 4.00%; Mn: 0.01% to 3.00%; P: 0.010% to 0.040%; S: 0.0001% to 0.0100%; Cr: 10.0% to 15.0%; N: 0.001% to 0.020%; Al: 0.50% to 10.0%; and either one or both of Ti: 0.05% to 0.40% and Nb: 0.05% to 0.40%, with the balance being Fe and unavoidable impurities, in which Cr/(Si+Al) is 10.0 or less, and a specific gravity is 7.6 g/cm3 or less.
    Type: Application
    Filed: March 27, 2018
    Publication date: January 23, 2020
    Applicant: NIPPON STEEL Stainless Steel Corporation
    Inventors: Junichi HAMADA, Masatoshi ABE, Atsutaka HAYASHI