Patents by Inventor Junichiro Hirasawa

Junichiro Hirasawa 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: 7429302
    Abstract: A structural hot-rolled or cold-rolled stainless steel sheet having improved intergranular corrosion resistance and toughness at the welding heat affected zone and further having low strength and high elongation. The composition of the steel sheet contains less than about 0.008 mass percent of C; about 1.0 mass percent or less of Si; about 1.5 mass percent or less of Mn; about 11 to about 15 mass percent of Cr; more than about 1.0 mass percent and about 2.5 mass percent or less of Ni; less than about 0.10 mass percent of Al; about 0.009 mass percent or less of N; about 0.04 mass percent or less of P; about 0.01 mass percent or less of S; and the balance being Fe and incidental impurities. These contents satisfy the expressions: (Cr)+1.2×(Ni)?15.0; (Ni)+0.5×(Mn)+30×(C)?3.0; (C)+(N)?0.015; and (Cr)?(Mn)?1.7×(Ni)?27×(C)?100×(N)?9.0.
    Type: Grant
    Filed: March 24, 2003
    Date of Patent: September 30, 2008
    Assignee: JFE Steel Corporation
    Inventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
  • Patent number: 7341690
    Abstract: The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10×(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si?1.2?0.4Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.
    Type: Grant
    Filed: December 9, 2003
    Date of Patent: March 11, 2008
    Assignee: JFE Steel Corporation
    Inventors: Atsushi Miyazaki, Junichiro Hirasawa, Mineo Muraki, Yoshihiro Yazawa, Osamu Furukimi
  • Publication number: 20080000737
    Abstract: A stainless steel sheet with excellent heat and corrosion resistances for a brake disk is provided. Specifically, in mass %, C: less than 0.10%, Si: 1.0% or less, Mn: 1.0 to 2.5%, P: 0.04% or less, S: 0.01% or less, Cr: more than 11.5% but not more than 15.0%, Ni: 0.1 to 1.0%, Al: 0.10% or less, Nb: more than 0.08% but not more than 0.6%, V: 0.02 to 0.3%, and N: more than 0.03% but not more than 0.10% are contained so that 0.03?{C+N?(13/93)Nb}?0.10, (5Cr+10Si+15Mo+30Nb+50V?9Ni?5Mn?3Cu?225N?270C)?45, and {(14/50)V+(14/90)Nb}<N (wherein Cr, Si, Mo, Nb, Ni, Mn, Cu, V, N, and C represent the contents (mass %) of the corresponding elements) are satisfied. With such a composition, the stainless steel sheet for a brake disk can be provided with both excellent heat resistance and excellent corrosion resistance after tempering.
    Type: Application
    Filed: October 20, 2005
    Publication date: January 3, 2008
    Applicant: JFE Steel Corporation, a corporation of Japan
    Inventors: Junichiro Hirasawa, Takumi Ojiro, Osamu Furukimi
  • Patent number: 7294212
    Abstract: Material for stainless steel sheets is heated to a temperature within a range of 850 to 1250° C. and cooled at a rate 1° C./s or faster, the material including 0.02% by mass or less of C, 1.0% by mass or less of Si, 2.0% by mass or less of Mn, 0.04% by mass or less of P, 0.01% by mass or less of S, 0.1% by mass or less of Al, 11% by mass or more but less than 17% by mass of Cr, 0.5% by mass or more but, less than 3.0% by mass of Ni, and 0.02% by mass or less of N, so as to satisfy specific relationships between the compositions.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: November 13, 2007
    Assignee: JFE Steel Corporation
    Inventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
  • Publication number: 20060113008
    Abstract: A martensitic stainless steel, having high temper softening resistance, for disc brakes is provided. The martensitic stainless steel is not seriously softened by maintaining the steel at more than 600° C. The steel has a hardness of 32 or more or a hardness of 30 or more in HRC after the steel is tempered at 650° C. for one hour or tempered at 670° C. for one hour, respectively. In particular, the martensitic stainless steel for disc brakes contains less than 0.050 mass % carbon, 1.0 mass % or less silicon, 2.0 mass % or less manganese, 0.04 mass % or less phosphorus, 0.010 mass % or less sulfur, 0.2 mass % or less aluminum, more than 11.5 mass % to 15.0 mass % chromium, 0.5 mass % to 2.0 mass % nickel, more than 0.50 mass % to 4.0 mass %. copper, more than 0.08 mass % to 0.6 mass % niobium, and less than 0.09 mass % nitrogen, the remainder being iron and unavoidable impurities.
    Type: Application
    Filed: April 23, 2004
    Publication date: June 1, 2006
    Applicant: JFE STEEL CORPORATION
    Inventors: Junichiro Hirasawa, Yoshihiro Ozaki, Takumi Ujiro, Osamu Furukimi
  • Publication number: 20040244878
    Abstract: The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10×(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si≦1.2−0.4Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.
    Type: Application
    Filed: December 9, 2003
    Publication date: December 9, 2004
    Applicant: JFE STEEL CORPORATION
    Inventors: Atsushi Miyazaki, Junichiro Hirasawa, Mineo Muraki, Yoshihiro Yazawa, Osamu Furukimi
  • Publication number: 20040226634
    Abstract: Material for stainless steel sheets is heated to a temperature within a range of 850 to 1250° C. and cooled at a rate 1° C./s or faster, the material including 0.02% by mass or less of C, 1.0% by mass or less of Si, 2.0% by mass or less of Mn, 0.04% by mass or less of P, 0.01% by mass or less of S, 0. 1% by mass or less of Al, 11% by mass or more but less than 17% by mass of Cr, 0.5% by mass or more but, less than 3.0% by mass of Ni, and 0.02% by mass or less of N, so as to satisfy specific relationships between the compositions.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 18, 2004
    Applicant: JFE STEEL CORPORATION
    Inventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
  • Patent number: 6740174
    Abstract: The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10×(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si ≦1.2−0.4 Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.
    Type: Grant
    Filed: November 14, 2001
    Date of Patent: May 25, 2004
    Assignee: JFE Steel Corporation
    Inventors: Atsushi Miyazaki, Junichiro Hirasawa, Mineo Muraki, Yoshihiro Yazawa, Osamu Furukimi
  • Patent number: 6737018
    Abstract: A corrosion-resistant chromium steel for architectural and civil engineering structural elements, includes 0.0015 to 0.02 mass percent C, 0.0015 to 0.02 mass percent N, 0.1 to 1.0 mass percent Si, 0.1 to 3.0 mass percent Mn, more than 5 mass percent to less than 10 mass percent Cr, 0.01 to 3.0 mass percent Ni, 0.1 mass percent or less of Al, 0.05 mass percent or less of P, 0.03 mass percent or less of S, 0.01 to 1.0 mass percent Co, and the balance being Fe and incidental impurities. The steel has high long-term corrosion resistance and high weld-zone toughness. Preferably, the steel further includes 0.01 to 0.5 mass percent V and 0.001 to 0.05 mass percent W, the Cr content is in the range of more than 5 mass percent to less than 8 mass percent, and the Cr, V, and W contents are within a specified ratio.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: May 18, 2004
    Assignee: JFE Steel Corporation
    Inventors: Hiroki Ota, Takumi Ujiro, Junichiro Hirasawa, Osamu Furukimi
  • Publication number: 20030188813
    Abstract: A structural hot-rolled or cold-rolled stainless steel sheet having improved intergranular corrosion resistance and toughness at the welding heat affected zone and further having low strength and high elongation. The composition of the steel sheet contains less than about 0.008 mass percent of C; about 1.0 mass percent or less of Si; about 1.5 mass percent or less of Mn; about 11 to about 15 mass percent of Cr; more than about 1.0 mass percent and about 2.5 mass percent or less of Ni; less than about 0.10 mass percent of Al; about 0.009 mass percent or less of N; about 0.04 mass percent or less of P; about 0.01 mass percent or less of S; and the balance being Fe and incidental impurities. These contents satisfy the expressions: (Cr)+1.2×(Ni)≧15.0; (Ni)+0.5×(Mn)+30×(C)≦3.0; (C)+(N)≦0.015; and (Cr)−(Mn)−1.7×(Ni)−27×(C)−100×(N)≧9.0.
    Type: Application
    Filed: March 24, 2003
    Publication date: October 9, 2003
    Applicant: KAWASAKI STEEL CORPORATION
    Inventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
  • Publication number: 20030138342
    Abstract: A martensitic stainless steel sheet having superior corrosion resistance, toughness at the weld zones, and workability. The composition of the steel sheet is, on a mass basis: less than about 0.02% of carbon; about 1.0% or less of silicon; less than about 1.5% of manganese; about 0.04% or less of phosphorus; about 0.01% or less of sulfur; about 0.1% or less of aluminum; about 1.5% or more and less than about 4.0% of nickel; about 11% or more and less than about 15% of chromium; about 0.5% or more and less than about 2.0% of molybdenum; and less than about 0.02% of nitrogen, the balance being iron and unavoidable impurities, wherein 15.0%≦[Cr]+1.5×[Mo]+1.2×[Ni]≦20.0%; [C]+[N]<0.030%; [Ni]+0.5×([Mn]+[Mo])+30×[C]>3.0%; and 8.
    Type: Application
    Filed: December 23, 2002
    Publication date: July 24, 2003
    Applicant: Kawasaki Steel Corporation
    Inventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
  • Publication number: 20030044305
    Abstract: The present invention provides Cr-containing steel that has satisfactory levels in all of toughness, strength (hardness) and corrosion resistance of HAZ, and that is suitably used as parts for welded structures.
    Type: Application
    Filed: June 12, 2002
    Publication date: March 6, 2003
    Inventors: Atsushi Miyazaki, Junichiro Hirasawa, Susumu Satoh, Sadao Hasuno, Makoto Kobayashi, takaaki Toyooka, Makoto Kitazawa
  • Patent number: 6521056
    Abstract: A ferritic stainless steel sheet which has not only superior high-temperature fatigue characteristics, but also superior workability at room temperatures. The steel sheet contains, by weight percent, C: not more than 0.02%, Si: 0.2 to 1.0%, Mn: not more than 1.5%, Cr: 11.0 to 20.0%, Ni: 0.05 to 2.0%, Mo: 1.0 to 2.0%, Al: not more than 1.0%, Nb: 0.2 to 0.8%, and N: not more than 0.02%, balance essentially Fe, and an aspect ratio (dRD/dTD) of grain size in planes at ¼ and ¾ sheet thickness, seen a direction normal to a sheet surface, in the range of 1.03 to 1.35. The steel sheet has a thickness greater than 0.3 mm but not greater than 2.5 mm, and a yield strength Y.S.≦360 MPa and an r-value≧1.3 at 30° C., and wherein after maintaining the steel sheet at 900° C. for one hour, the Y.S.≧18.0 MPa.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: February 18, 2003
    Assignee: Kawasaki Steel Corporation
    Inventors: Mineo Muraki, Junichiro Hirasawa, Atsushi Miyazaki, Susumu Satoh
  • Publication number: 20020155019
    Abstract: A corrosion-resistant chromium steel for architectural and civil engineering structural elements, includes 0.0015 to 0.02 mass percent C, 0.0015 to 0.02 mass percent N, 0.1 to 1.0 mass percent Si, 0.1 to 3.0 mass percent Mn, more than 5 mass percent to less than 10 mass percent Cr, 0.01 to 3.0 mass percent Ni, 0.1 mass percent or less of Al, 0.05 mass percent or less of P, 0.03 mass percent or less of S, 0.01 to 1.0 mass percent Co, and the balance being Fe and incidental impurities. The steel has high long-term corrosion resistance and high weld-zone toughness. Preferably, the steel further includes 0.01 to 0.5 mass percent V and 0.001 to 0.05 mass percent W, the Cr content is in the range of more than 5 mass percent to less than 8 mass percent, and the Cr, V, and W contents are within a specified ratio.
    Type: Application
    Filed: January 16, 2002
    Publication date: October 24, 2002
    Applicant: KAWASAKI STEEL CORPORATION
    Inventors: Hiroki Ota, Takumi Ujiro, Junichiro Hirasawa, Osamu Furukimi
  • Patent number: 6426039
    Abstract: Ferritic stainless steel comprising all three of Co, V, and B, having a Co content of about 0.01 mass % to about 0.3 mass %, a V content of about 0.01 mass % to about 0.3 mass %, and a B content of about 0.0002 mass % to about 0.0050 mass %, and having superior secondary working embrittleness resistance and superior high temperature fatigue characteristics.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: July 30, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Junichiro Hirasawa, Atsushi Miyazaki, Mineo Muraki, Susumu Satoh
  • Publication number: 20020098107
    Abstract: The soft Cr-containing steel includes, on a % by mass basis, C: from about 0.001% to about 0.020%, Si: more than about 0.10% and less than about 0.50%, Mn: less than about 2.00%, P: less than about 0.060%, S: less than about 0.008%, Cr: from about 12.0% to about 16.0%, Ni: from about 0.05% to about 1.00%, N: less than about 0.020%, Nb: from about 10×(C+N) to about 1.00%, Mo: more than about 0.80% and less than about 3.00%, wherein the contents of alloying elements, represented by Si and Mo, respectively, on a % by mass, satisfy the formula Si ≦1.2-0.4 Mo, so as to prevent precipitation of the Laves phase and to stably secure an effect of increasing high-temperature strength due to solid solution Mo.
    Type: Application
    Filed: November 14, 2001
    Publication date: July 25, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Atsushi Miyazaki, Junichiro Hirasawa, Mineo Muraki, Yoshihiro Yazawa, Osamu Furukimi
  • Publication number: 20020036036
    Abstract: A ferritic stainless steel sheet which has not only superior high-temperature fatigue characteristics, but also superior workability at room temperatures. The steel sheet contains, by weight percent, C: not more than 0.02%, Si: 0.2 to 1.0%, Mn: not more than 1.5%, Cr: 11.0 to 20.0%, Ni: 0.05 to 2.0%, Mo: 1.0 to 2.0%, Al: not more than 1.0%, Nb: 0.2 to 0.8%, and N: not more than 0.02%, balance essentially Fe, and an aspect ratio (dRD/dTD) of grain size in planes at ¼ and ¾ sheet thickness, seen a direction normal to a sheet surface, in the range of 1.03 to 1.35. The steel sheet has a thickness greater than 0.3 mm but not greater than 2.5 mm, and a yield strength Y.S.≦360 MPa and an r-value≧1.3 at 30° C., and wherein after maintaining the steel sheet at 90° C. for one hour, the Y.S.≧18.0 MPa.
    Type: Application
    Filed: July 25, 2001
    Publication date: March 28, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Mineo Muraki, Junichiro Hirasawa, Atsushi Miyazaki, Susumu Satoh
  • Publication number: 20020007876
    Abstract: Ferritic stainless steel comprising all three of Co, V, and B, having a Co content of about 0.01 mass % to about 0.3 mass %, a V content of about 0.01 mass % to about 0.3 mass %, and a B content of about 0.0002 mass % to about 0.0050 mass %, and having superior secondary working embrittleness resistance and superior high temperature fatigue characteristics.
    Type: Application
    Filed: June 27, 2001
    Publication date: January 24, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Junichiro Hirasawa, Atsushi Miyazaki, Mineo Muraki, Susumu Satoh
  • Patent number: 6168756
    Abstract: A highly corrosion resistant chromium-containing steel has corrosion resistance and oxidation resistance comparable or superior to those of low Cr-stainless steel (Cr content: 11-13% by weight), and excellent intergranular corrosion resistance not attainable in existing chromium containing steels. However, the steel has such a low Cr content that it is not classified as a stainless steel. A preferred composition on a weight % basis, is: C: 0.015% or less, Si: from more than 1.0% to 2.0%, Mn: 0.5% or less, P: 0.05% or less, S: 0.01 or less, Ni: 0.015% or less, provided that sum of the C content and the N content (C+N): 0.020% or less. Ti: from more than 0.30% to 0.50% in which the contents for Cr, Ti, C and N, that is, [Cr], [Ti], [C] and [N] satisfying the following relation: [Ti]/([C]+[N])≧64−4×[Cr], balance of Fe and incidental impurities.
    Type: Grant
    Filed: November 1, 1999
    Date of Patent: January 2, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Junichiro Hirasawa, Atsushi Miyazaki, Kazuhide Ishii, Susumu Satoh, Haruhiko Ishizuka