Patents by Inventor Mitsuyuki Fujisawa

Mitsuyuki Fujisawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11008636
    Abstract: A stainless steel foil having a chemical composition comprising, by mass %, C: 0.015% or less, Si: 0.50% or less, Mn: 0.50% or less, P: 0.040% or less, S: 0.010% or less, Cr: 10.0% or more and less than 16.0%, Al: 2.5 to 4.5%, N: 0.015% or less, Ni: 0.05 to 0.50%, Cu: 0.01 to 0.10%, Mo: 0.01 to 0.15%, at least one selected from the group consisting of Ti: 0.01 to 0.30%, Zr: 0.01 to 0.20%, Hf: 0.01 to 0.20%, and REM: 0.01 to 0.20%, where Ti+Zr+Hf+2REM?0.06 and 0.30?Ti+Zr+Hf are satisfied.
    Type: Grant
    Filed: October 16, 2017
    Date of Patent: May 18, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Akito Mizutani, Mitsuyuki Fujisawa
  • Patent number: 10968499
    Abstract: Ferritic stainless steel that has excellent formability and ridging resistance and can be produced with high productivity is provided. The ferritic stainless steel has: a predetermined chemical composition; a microstructure containing ferrite crystal grains which satisfy at least one of a C concentration of 2CC or more and an N concentration of 2CN or more, the ferrite crystal grains having a volume fraction with respect to a whole volume of the microstructure of 5% or more and 50% or less, where CC and CN are respectively C content and N content in the steel in mass %; and a Vickers hardness of 180 or less.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: April 6, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Akito Mizutani, Masataka Yoshino, Mitsuyuki Fujisawa, Ayako Ta
  • Publication number: 20210059019
    Abstract: A Fe—Cr alloy having a chemical composition with increased Si and Al contents, in which the chemical composition satisfies the following formula (1) in terms of the Si content, Al content, and Cr content: 14.0?% Si+1.15×% Al+0.35×% Cr ??(1).
    Type: Application
    Filed: December 5, 2018
    Publication date: February 25, 2021
    Applicant: JFE STEEL CORPORATION
    Inventors: Akito MIZUTANI, Tatsuhiko HIRATANI, Mitsuyuki FUJISAWA
  • Publication number: 20200385835
    Abstract: The present invention provides a hot-rolled and annealed ferritic stainless steel sheet which has sufficient corrosion resistance and in which cracks can be prevented during blanking into a thick flange, and a method for manufacturing the same. A hot-rolled and annealed ferritic stainless steel sheet has a chemical composition containing, in percent by mass, C: 0.001% to 0.020%, Si: 0.05% to 1.00%, Mn: 0.05% to 1.00%, P: 0.04% or less, S: 0.01% or less, Al: 0.001% to 0.100%, Cr: 10.0% to 19.0%, Ni: 0.65% to 1.50%, Ti: 0.10% to 0.40%, and N: 0.001% to 0.020%, with the balance being Fe and unavoidable impurities, and has a threshold stress intensity factor KIC of 35 MPa·m1/2 or more.
    Type: Application
    Filed: April 24, 2018
    Publication date: December 10, 2020
    Applicant: JFE Steel Corporation
    Inventors: Masataka Yoshino, Keishi Inoue, Mitsuyuki Fujisawa
  • Publication number: 20200385834
    Abstract: A raw material for a steel sheet, the raw material being suitable for manufacturing a cold-rolled ferritic stainless steel sheet having excellent corrosion resistance, formability, and ridging resistance, and a manufacturing method therefor are provided. A raw material for a cold-rolled stainless steel sheet has a chemical composition containing, in terms of mass %, C: 0.005 to 0.030%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.040% or less, S: 0.030% or less, Al: 0.001 to 0.150%, Cr: 10.8 to 14.4%, Ni: 0.01 to 2.50%, and N: 0.005 to 0.060%, with the balance being Fe and incidental impurities, in which the raw material has a structure containing 10 to 90% of a martensite phase in terms of area ratio with the balance being a ferrite phase.
    Type: Application
    Filed: April 13, 2018
    Publication date: December 10, 2020
    Applicant: JFE Steel Corporation
    Inventors: Shuji Nishida, Tomohiro Ishii, Masataka Yoshino, Mitsuyuki Fujisawa
  • Publication number: 20200377980
    Abstract: Provided is a hot-rolled and annealed ferritic stainless steel sheet excellent in surface quality after bending work has been performed. A hot-rolled and annealed ferritic stainless steel sheet has a thickness of 5.0 mm or more and a chemical composition containing, by mass %, C: 0.001% to 0.025%, Si: 0.05% to 0.70%, Mn: 0.05% to 0.50%, P: 0.050% or less, S: 0.01% or less, Cr: 10.0% to 18.0%, Ni: 0.01% to 1.00%, Al: 0.001% to 0.10%, N: 0.001% to 0.025%, Ti: 0.01% to 0.40%, and a balance of Fe and inevitable impurities, in which a difference between maximum and minimum values of an average crystal grain diameter determined by using measuring method 1 is 50 ?m or less, and in which a difference between maximum and minimum values of a crystal grain elongation rate determined by using measuring method 2 is 5.0 or less.
    Type: Application
    Filed: September 21, 2018
    Publication date: December 3, 2020
    Applicant: JFE Steel Corporation
    Inventors: Hidetaka Kawabe, Mitsuyuki Fujisawa, Hiroshi Shimizu, Tomohiko Uchino
  • Publication number: 20200347475
    Abstract: The present invention provides a ferritic stainless steel sheet and a method for manufacturing the same. A ferritic stainless steel sheet has a composition containing C: 0.001 to 0.020%, Si: 0.05 to 0.35%, Mn: 0.05 to 1.00%, P: 0.04% or less, S: 0.01% or less, Al: 0.001 to 0.300%, Cr: 10.0 to 13.0%, Ni: 0.75 to 1.50%, Ti: 0.05 to 0.35%, and N: 0.001 to 0.020%, with the balance being Fe and inevitable impurities, in which ?I [AD] represented by formula (1) below is 65% or more, and a metal structure has an average crystal grain size of 45 ?m or less: ?I [%]=24Ni+12Mn+6Cu?18Si?12Cr?12Mo+188 (1), where Ni, Mn, Cu, Si, Cr, and Mo represent contents of the respective elements (percent by mass), and an element not contained represents 0.
    Type: Application
    Filed: October 16, 2018
    Publication date: November 5, 2020
    Applicant: JFE Steel Corporation
    Inventors: Keishi Inoue, Hidetaka Kawabe, Masataka Yoshino, Mitsuyuki Fujisawa
  • Patent number: 10821706
    Abstract: Disclosed is a ferritic stainless steel sheet including: a chemical composition containing, by mass %, C: 0.025% or less, Si: 0.01% to 2.0%, Mn: 0.01% to 1.0%, P: 0.050% or less, S: 0.010% or less, Cr: 10.5% to 20.0%, Al: 0.01% to 0.50%, Ni: 0.01% to 0.60%, Ti: 0.10% to 0.50%, and N: 0.025% or less, with the balance being Fe and inevitable impurities; and a coating layer including at least one coating layer selected from the group consisting of an Al coating layer, an Fe coating layer, and a Si coating layer on one or both sides thereof, in which the coating layer has a total thickness of 30 nm to 150 nm per side.
    Type: Grant
    Filed: April 21, 2017
    Date of Patent: November 3, 2020
    Assignee: JFE STEEL CORPORATION
    Inventors: Akito Mizutani, Mitsuyuki Fujisawa
  • Patent number: 10801084
    Abstract: Provided are a material for cold rolled stainless steel sheets having sufficient corrosion resistance, excellent surface quality, excellent formability, and excellent ridging resistance; a method for manufacturing the same; and a cold rolled steel sheet. A material for cold rolled stainless steel sheets according to the present invention contains C: 0.005% to 0.025%, Si: 0.02% to 0.50%, Mn: 0.55% to 1.0%, P: 0.040% or less, S: 0.01% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, and N: 0.005% to 0.025% on a mass basis, the remainder being Fe and inevitable impurities, and has a metallographic structure containing 5% to 20% of a martensite phase in terms of volume fraction, the remainder being a ferrite phase.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: October 13, 2020
    Assignee: JFE Steel Corporation
    Inventors: Akito Mizutani, Masataka Yoshino, Mitsuyuki Fujisawa, Chikara Kami
  • Publication number: 20200308677
    Abstract: Provided is a ferritic stainless steel sheet excellent in shape of weld zone and corrosion resistance of a weld zone with a material of a different kind formed by performing welding with austenitic stainless steel. A ferritic stainless steel sheet having a chemical composition containing, by mass %, C: 0.003% to 0.020%, Si: 0.01% to 1.00%, Mn: 0.01% to 0.50%, P: 0.040% or less, S: 0.010% or less, Cr: 20.0% to 24.0%, Cu: 0.20% to 0.80%, Ni: 0.01% to 0.60%, Al: 0.01% to 0.08%, N:. 0.003% to 0.020%, Nb: 0.40% to 0.80%, Ti: 0.01% to 0.10%, Zr: 0.01% to 0.10%, and the balance being Fe and inevitable impurities, in which relational expression (1) below is satisfied: 3.0?Nb/(2Ti+Zr+0.5 Si+5 Al)?1.5 ??(1), here, in relational expression (1), each of the atomic symbols denotes the content (mass %) of the corresponding chemical element.
    Type: Application
    Filed: June 15, 2017
    Publication date: October 1, 2020
    Applicant: JFE Steel Corporation
    Inventors: Hidetaka Kawabe, Shuji Nishida, Mitsuyuki Fujisawa, Chikara Kami
  • Publication number: 20200299800
    Abstract: A ferritic stainless steel sheet having excellent corrosion resistance, formability, and ridging resistance and a method for manufacturing the same are provided. A ferritic stainless steel sheet has a chemical composition containing, in terms of mass %, C: 0.005 to 0.030%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.040% or less, S: 0.030% or less, Al: 0.001 to 0.150%, Cr: 10.8 to 14.4%, Ni: 0.01 to 2.50%, and N: 0.005 to 0.060%, with the balance being Fe and incidental impurities. The elongation after fracture is 28% or more, and the ridging height of a surface of a steel sheet to which a tensile strain of 23% has been applied in a rolling direction is 3.0 ?m or less.
    Type: Application
    Filed: April 13, 2018
    Publication date: September 24, 2020
    Applicant: JFE STEEL CORPORATION
    Inventors: Shuji NISHIDA, Tomohiro ISHII, Masataka YOSHINO, Mitsuyuki FUJISAWA
  • Patent number: 10745774
    Abstract: A ferrite-martensite dual-phase stainless steel has satisfactory corrosion resistance and workability for a material for the body of a freight car and excellent low-temperature toughness. The ferrite-martensite dual-phase stainless steel has a specified chemical composition, in which inequalities (I) and (II) below are satisfied, and a steel microstructure including a dual phase of a ferrite phase and a martensite phase, in which the content of the martensite phase is 5% or more and 95% or less in terms of vol. %: 10.5?Cr+1.5×Si?13.5??(I) 1.5?30×(C+N)+Ni+0.5×Mn?6.0??(II), where Cr and Si in inequality (I) above and C, N, Ni, and Mn in inequality (II) above respectively represent the contents (mass %) of the corresponding chemical elements.
    Type: Grant
    Filed: October 27, 2014
    Date of Patent: August 18, 2020
    Assignee: JFE Steel Corporation
    Inventors: Tomohiro Ishii, Hiroki Ota, Chikara Kami, Saiichi Murata, Mitsuyuki Fujisawa, Genichi Ishibashi
  • Patent number: 10655195
    Abstract: The disclosure is to provide a martensitic stainless steel excellent in strength, workability and corrosion resistance. The martensitic stainless steel comprises a chemical composition containing, in mass %: C: 0.020% or more and less than 0.10%, Si: 0.01% or more and 2.0% or less, Mn: 0.01% or more and 3.0% or less, P: 0.050% or less, S: 0.050% or less, Cr: 10.0% or more and 16.0% or less, Ni: 0.01% or more and 0.80% or less, Al: 0.001% or more and 0.50% or less, and N: more than 0.050% and 0.20% or less, satisfying N % C %, and the balance containing Fe and incidental impurities, where C % and N % indicate respectively the contents of C and N (mass %) in the steel.
    Type: Grant
    Filed: April 15, 2016
    Date of Patent: May 19, 2020
    Assignee: JFE STEEL CORPORATION
    Inventors: Tetsuyuki Nakamura, Takashi Samukawa, Mitsuyuki Fujisawa, Chikara Kami
  • Patent number: 10626486
    Abstract: Stainless steel that has excellent formability and ridging resistance and can be produced with high productivity is provided. The stainless steel comprises: a chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, and N: 0.005% to 0.06%, with a balance being Fe and incidental impurities; and a microstructure containing a martensite phase of 1% to 10% in volume fraction with respect to a whole volume of the microstructure.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: April 21, 2020
    Assignee: JFE STEEL CORPORATION
    Inventors: Akito Mizutani, Masataka Yoshino, Mitsuyuki Fujisawa, Ayako Ta
  • Publication number: 20200002779
    Abstract: Provided is a hot-rolled ferritic stainless steel sheet which has sufficient corrosion resistance and which can prevent the occurrence of cracking when subjected to blanking to be formed into a thick flange, and also provided is a method for manufacturing the hot-rolled ferritic stainless steel sheet. A hot-rolled ferritic stainless steel sheet having a chemical composition containing, in mass %, C: 0.001 to 0.020%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.04% or less, S: 0.01% or less, Al: 0.001 to 0.50%, N: 0.001 to 0.020%, Cr: 11.0 to 24.0%, Ni: 0.01 to 2.00%, and Nb: 0.12 to 0.80%, with the balance being Fe and incidental impurities, wherein the hot-rolled ferritic stainless steel sheet has a threshold stress intensity factor KIC of 25 MPa·m1/2 or more.
    Type: Application
    Filed: January 12, 2018
    Publication date: January 2, 2020
    Applicant: JFE Steel Corporation
    Inventors: Masataka YOSHINO, Mitsuyuki FUJISAWA
  • Publication number: 20190390310
    Abstract: Provided is a ferritic-austenitic duplex stainless steel sheet in which no blowholes are formed during welding and which has excellent strength. A chemical composition includes, in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 2.0 to 7.0%, P: 0.07% or less, S: 0.030% or less, Cr: 18.0 to 24.0%, Ni: 0.1 to 3.0%, Mo: 0.01 to 1.0%, Cu: 0.1 to 3.0%, Al: 0.003 to 0.10%, Zr: 0.01 to 0.50%, and N: 0.15 to 0.30%, with the balance being Fe and incidental impurities, the chemical composition satisfying formula (1) below and formula (2) below. N—Zr/6.5?0.15%??(1) N—Zr/6.5?0.23%??(2) Here, in formula (1) and formula (2), N represents a content (mass %) of the corresponding chemical element N and Zr represents a content (mass %) of the corresponding chemical element Zr.
    Type: Application
    Filed: January 18, 2018
    Publication date: December 26, 2019
    Applicant: JFE Steel Corporation
    Inventors: Akito Mizutani, Mitsuyuki Fujisawa
  • Patent number: 10458013
    Abstract: Provided is a ferritic stainless steel having a chemical composition containing, in mass %: 0.003% to 0.025% of C; 0.05% to 1.00% of Si; 0.05% to 1.00% of Mn; 0.04% or less of P; 0.01% or less of S; 16.0% to 23.0% of Cr; 0.20% to 0.80% of Cu; 0.05% to 0.60% of Ni; 0.20% to 0.70% of Nb; 0.005% to 0.020% of N; and the balance being Fe and incidental impurities, in which a nitrogen-enriched layer is present that has a nitrogen concentration peak value of 0.03 mass % to 0.30 mass % at a depth of within 0.05 ?m of a surface of the steel.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: October 29, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Kunio Fukuda, Shin Ishikawa, Mitsuyuki Fujisawa, Katsuhisa Yamauchi, Chikara Kami
  • Patent number: 10450625
    Abstract: Provided is a ferritic stainless steel that has excellent corrosion resistance and displays good brazing properties when brazing is carried out at high temperature using a Ni-containing brazing metal. These effects are obtained as a result of the steel having a chemical composition containing, in mass %: 0.003%-0.020% of C; 0.05%-1.00% of Si; 0.10%-0.50% of Mn, 0.04% or less of P; 0.01% or less of S; 16.0%-25.0% of Cr; 0.05%-0.60% of Ni; 0.25%-0.45% of Nb; 0.005%-0.15% of Al; 0.005%-0.030% of N; and at least one selected from 0.50%-2.50% of Mo and 0.05%-0.80% of Cu, the balance being Fe and incidental impurities, and as a result of a nitrogen-enriched layer being created that has a nitrogen concentration peak value of 0.03 to 0.30 mass % at a depth of within 0.05 ?m of a surface of the steel.
    Type: Grant
    Filed: July 23, 2015
    Date of Patent: October 22, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Kunio Fukuda, Mitsuyuki Fujisawa, Tomohiro Ishii, Shin Ishikawa, Chikara Kami
  • Publication number: 20190275766
    Abstract: Disclosed is a ferritic stainless steel sheet including: a chemical composition containing, by mass %, C: 0.025% or less, Si: 0.01% to 2.0%, Mn: 0.01% to 1.0%, P: 0.050% or less, S: 0.010% or less, Cr: 10.5% to 20.0%, Al: 0.01% to 0.50%, Ni: 0.01% to 0.60%, Ti: 0.10% to 0.50%, and N: 0.025% or less, with the balance being Fe and inevitable impurities; and a coating layer including at least one coating layer selected from the group consisting of an Al coating layer, an Fe coating layer, and a Si coating layer on one or both sides thereof, in which the coating layer has a total thickness of 30 nm to 150 nm per side.
    Type: Application
    Filed: April 21, 2017
    Publication date: September 12, 2019
    Applicant: JFE STEEL CORPORATION
    Inventors: Akito MIZUTANI, Mitsuyuki FUJISAWA
  • Publication number: 20190249269
    Abstract: A stainless steel foil having a chemical composition comprising, by mass %, C: 0.015% or less, Si: 0.50% or less, Mn: 0.50% or less, P: 0.040% or less, S: 0.010% or less, Cr: 10.0% or more and less than 16.0%, Al: 2.5 to 4.5%, N: 0.015% or less, Ni: 0.05 to 0.50%, Cu: 0.01 to 0.10%, Mo: 0.01 to 0.15%, at least one selected from the group consisting of Ti: 0.01 to 0.30%, Zr: 0.01 to 0.20%, Hf: 0.01 to 0.20%, and REM: 0.01 to 0.20%, where Ti+Zr+Hf+2REM?0.06 and 0.30?Ti+Zr+Hf are satisfied.
    Type: Application
    Filed: October 16, 2017
    Publication date: August 15, 2019
    Applicant: JFE STEEL CORPORATION
    Inventors: Akito MIZUTANI, Mitsuyuki FUJISAWA