Patents by Inventor Junji Haji
Junji Haji 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).
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Patent number: 10384256Abstract: Tooling used in a punching process which uses a die and projecting punch to form a worked material of steel sheet into a predetermined outer shape, in which tooling for punching, a radius of curvature Rd of a die cutting edge is from 0.03 mm to 0.2 mm and an angle (?) formed by a tangent drawn from a punch cutting edge to a projection shoulder and a direction perpendicular to a direction of movement of the punch is from 12° to 72°, and a punching method and shaping method using the same, are provided. Further, when making the die cutting edge (shoulder R part) a two-stage R of radii of curvature R1 and R2 and making a slant of a line passing through the centers of R1 and R2 ?, by making 0.03 mm?R1?0.2 mm, 1?R2/R1?5, 0?R2(1?sin ?1)?0.3t, and 30°???90°, punching hole expandability can be improved.Type: GrantFiled: November 11, 2014Date of Patent: August 20, 2019Assignee: NIPPON STEEL CORPORATIONInventors: Yuzo Takahashi, Osamu Kawano, Tatsuo Yokoi, Junji Haji, Satoshi Horioka
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Patent number: 10273566Abstract: A hot-rolled steel sheet includes, as a chemical composition, by mass %, C: 0.030% to 0.10%, Mn: 0.5% to 2.5%, and Si+Al: 0.100% to 2.5%, in which the steel sheet has a microstructure including, by area fraction, ferrite: 80% or more, martensite: 3% to 15.0%, and pearlite: less than 3.0%, in which a number density of martensite having an equivalent circle diameter of 3 ?m or more at a position which is at a depth of ¼ of the steel sheet thickness from the surface of the steel sheet, is 5.0 pieces/10000 ?m2 or less, and the following Expression (1) is satisfied. R/DM2?1.00??Expression (1) Here, R is an average martensite interval (?m) defined by the following Expression (2), and DM is a martensite average diameter (?m). R={12.5×(?/6VM)0.5?(?)0.5}×DM??Expression (2) Here, VM is a martensite area fraction (%) and DM is the martensite average diameter (?m).Type: GrantFiled: December 11, 2012Date of Patent: April 30, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Daisuke Maeda, Osamu Kawano, Junji Haji, Fuminori Tasaki
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Patent number: 10023931Abstract: The present invention provides a method of production of hot dip galvannealed steel sheet with excellent workability compared with the Sendzimir method or non-oxidizing furnace method and further with excellent powdering or slidability, that is, a method of production of hot dip galvannealed steel sheet with excellent workability, powdering, and slidability characterized by processing a slab containing, by mass %, C: 0.01 to 0.12%, Mn: 0.05 to 0.6%, Si: 0.002 to 0.1%, P: 0.05% or less, S: 0.03% or less, sol. Al: 0.005 to 0.1%, and N: 0.01% or less and having a balance of Fe and unavoidable impurities by hot rolling, pickling, cold rolling, then annealing at 650 to 900° C., cooling to 250 to 450° C., holding at said temperature range for 120 seconds or more, then cooling to room temperature, pickling, preplating Ni or Ni—Fe without intermediate temper rolling, heating by 5° C./sec or more down to 430 to 500° C., galvanizing in a galvanization bath, wiping, then heating by a rate of temperature rise of 20° C.Type: GrantFiled: March 28, 2007Date of Patent: July 17, 2018Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Junji Haji, Kaoru Kawasaki, Kiyokazu Ishizuka, Teruaki Yamada
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Patent number: 9732405Abstract: A hot rolled steel sheet includes, as a chemical composition, at least one selected from Ti, REM, and Ca, and includes, as a metallographic structure, a ferrite as a primary phase, at least one of a martensite and a residual austenite as a secondary phase, and plural inclusions, wherein a total length in the rolling direction of both inclusion-cluster whose length in the rolling direction is 30 ?m or more and independent-inclusion whose length in the rolling direction is 30 ?m or more is 0 mm to 0.25 mm per 1 mm2.Type: GrantFiled: March 16, 2012Date of Patent: August 15, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Yuzo Takahashi, Junji Haji, Osamu Kawano
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Patent number: 9617626Abstract: The present invention provides a high-strength steel sheet including: C: 0.03 to 0.25 mass %, Si: 0.1 to 2.0 mass %, Mn: 0.5 to 3.0 mass %, P: not more than 0.05 mass %, T.O: not more than 0.0050 mass %, S: 0.0001 to 0.01 mass %, N: 0.0005 to 0.01 mass %, acid-soluble Al: more than 0.01 mass %, Ca: 0.0005 to 0.0050 mass %, and a total of at least one element of Ce, La, Nd, and Pr: 0.001 to 0.01 mass %, with a balance including iron and inevitable impurities, in which the steel sheet contains a chemical component on a basis of mass that satisfies 0.7<100×([Ce]+[La]+[Nd]+[Pr])/[acid-soluble Al]?70 and 0.Type: GrantFiled: February 23, 2012Date of Patent: April 11, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kenichi Yamamoto, Hideaki Yamamura, Yuzo Takahashi, Osamu Kawano, Kohsuke Kume, Junji Haji, Daisuke Maeda, Yoshihiro Suwa
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Patent number: 9499894Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: GrantFiled: December 26, 2013Date of Patent: November 22, 2016Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20160243606Abstract: Punching hole expandability of high strength thin-gauge steel sheet is improved for the purpose of application of high strength thin-gauge steel sheet to auto parts so as to lighten the weight of automobiles. Tooling used in a punching process which uses a die and projecting punch to form a worked material of steel sheet into a predetermined outer shape, in which tooling for punching, a radius of curvature Rd of a die cutting edge is from 0.03 mm to 0.2 mm and an angle (?) formed by a tangent drawn from a punch cutting edge to a projection shoulder and a direction perpendicular to a direction of movement of the punch is from 12° to 72°, and a punching method and shaping method using the same, are provided. Further, when making the die cutting edge (shoulder R part) a two-stage R of radii of curvature R1 and R2 and making a slant of a line passing through the centers of R1 and R2 ?, by making 0.03 mm?R1?0.2 mm, 1?R2/R1?5, 0?R2(1?sin ?1)?0.3t, and 30°???90°, punching hole expandability can be improved.Type: ApplicationFiled: November 11, 2014Publication date: August 25, 2016Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Yuzo Takahashi, Osamu Kawano, Tatsuo Yokoi, Junji Haji, Satoshi Horioka
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Publication number: 20150315683Abstract: A hot-rolled steel sheet includes, as a chemical composition, by mass %, C: 0.030% to 0.10%, Mn: 0.5% to 2.5%, and Si+Al: 0.100% to 2.5%, in which the steel sheet has a microstructure including, by area fraction, ferrite: 80% or more, martensite: 3% to 15.0%, and pearlite: less than 3.0%, in which a number density of martensite having an equivalent circle diameter of 3 ?m or more at a position which is at a depth of ¼ of the steel sheet thickness from the surface of the steel sheet, is 5.0 pieces/10000 ?m2 or less, and the following Expression (I) is satisfied. R/DM2?1.00??Expression (1) Here, R is an average martensite interval (?m) defined by the following Expression (2), and DM is a martensite average diameter (?m). R={12.5×(?/6VM)0.5?(?)0.5}×DM??Expression (2) Here, VM is a martensite area fraction (%) and DM is the martensite average diameter (?m).Type: ApplicationFiled: December 11, 2012Publication date: November 5, 2015Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Daisuke MAEDA, Osamu KAWANO, Junji HAJI, Fuminori TASAKI
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Patent number: 9121079Abstract: On a cross section with a sheet width direction of a high-strength hot-rolled steel sheet set as a normal line, with regard to an inclusion having a major diameter of 3.0 ?m or more, a maximum of a major diameter/minor diameter ratio expressed by (a major diameter of the inclusion)/(a minor diameter of the inclusion) is 8.0 or less, and a sum total of a rolling direction length per 1 mm2 cross section of a predetermined inclusion group composed of plural inclusions each having a major diameter of 3.0 ?m or more and a predetermined extended inclusion having a length in a rolling direction of 30 ?m or more is 0.25 mm or less. The plural inclusions composing the predetermined inclusion group congregate in both the rolling direction and a direction perpendicular to the rolling direction 50 ?m or less apart from each other. The predetermined extended inclusion is spaced over 50 ?m apart from all the inclusions each having a major diameter of 3.Type: GrantFiled: March 9, 2011Date of Patent: September 1, 2015Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Yuzo Takahashi, Junji Haji, Osamu Kawano
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Publication number: 20140199487Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: ApplicationFiled: December 26, 2013Publication date: July 17, 2014Applicant: NIPPON STEEL CORPORATIONInventors: KIYOKAZU ISHIZUKA, KAZUMI NISHIMURA, IKUO KIKUCHI, KAORU KAWASAKI, JUNJI HAJI
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Publication number: 20140000769Abstract: A hot rolled steel sheet includes, as a chemical composition, at least one selected from Ti, REM, and Ca, and includes, as a metallographic structure, a ferrite as a primary phase, at least one of a martensite and a residual austenite as a secondary phase, and plural inclusions, wherein a total length in the rolling direction of both inclusion-cluster whose length in the rolling direction is 30 ?m or more and independent-inclusion whose length in the rolling direction is 30 ?m or more is 0 mm to 0.25 mm per 1 mm2.Type: ApplicationFiled: March 16, 2012Publication date: January 2, 2014Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Yuzo Takahashi, Junji Haji, Osamu Kawano
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Patent number: 8617324Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: GrantFiled: September 13, 2012Date of Patent: December 31, 2013Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20130142688Abstract: The present invention provides a high-strength steel sheet including: C: 0.03 to 0.25 mass %, Si: 0.1 to 2.0 mass %, Mn: 0.5 to 3.0 mass %, P: not more than 0.05 mass %, T.O: not more than 0.0050 mass %, S: 0.0001 to 0.01 mass %, N: 0.0005 to 0.01 mass %, acid-soluble Al: more than 0.01 mass %, Ca: 0.0005 to 0.0050 mass %, and a total of at least one element of Ce, La, Nd, and Pr: 0.001 to 0.01 mass %, with a balance including iron and inevitable impurities, in which the steel sheet contains a chemical component on a basis of mass that satisfies 0.7<100×([Ce]+[La]+[Nd]+[Pr])/[acid-soluble Al]?70 and 0.Type: ApplicationFiled: February 23, 2012Publication date: June 6, 2013Inventors: Kenichi Yamamoto, Hideaki Yamamura, Yuzo Takahashi, Osamu Kawano, Kohsuke Kume, Junji Haji, Daisuki Maeda, Yoshihiro Suwa
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Publication number: 20130008569Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: ApplicationFiled: September 13, 2012Publication date: January 10, 2013Applicant: Nippon Steel CorporationInventors: KIYOKAZU ISHIZUKA, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20130000791Abstract: On a cross section with a sheet width direction of a high-strength hot-rolled steel sheet set as a normal line, with regard to an inclusion having a major diameter of 3.0 ?m or more, a maximum of a major diameter/minor diameter ratio expressed by (a major diameter of the inclusion)/(a minor diameter of the inclusion) is 8.0 or less, and a sum total of a rolling direction length per 1 mm2 cross section of a predetermined inclusion group composed of plural inclusions each having a major diameter of 3.0 ?m or more and a predetermined extended inclusion having a length in a rolling direction of 30 ?m or more is 0.25 mm or less. The plural inclusions composing the predetermined inclusion group congregate in both the rolling direction and a direction perpendicular to the rolling direction 50 ?m or less apart from each other. The predetermined extended inclusion is spaced over 50 ?m apart from all the inclusions each having a major diameter of 3.Type: ApplicationFiled: March 9, 2011Publication date: January 3, 2013Inventors: Yuzo Takahashi, Junji Haji, Osamu Kawano
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Patent number: 8303739Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: GrantFiled: April 14, 2006Date of Patent: November 6, 2012Assignee: Nippon Steel CorporationInventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20090211668Abstract: Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430° C. to 500° C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.Type: ApplicationFiled: April 14, 2006Publication date: August 27, 2009Applicant: Nippon Steel CorporationInventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Kaoru Kawasaki, Junji Haji
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Publication number: 20090151820Abstract: The present invention provides a method of production of hot dip galvannealed steel sheet with excellent workability compared with the Sendzimir method or non-oxidizing furnace method and further with excellent powdering or slidability, that is, a method of production of hot dip galvannealed steel sheet with excellent workability, powdering, and slidability characterized by processing a slab containing, by mass %, C: 0.01 to 0.12%, Mn: 0.05 to 0.6%, Si: 0.002 to 0.1%, P: 0.05% or less, S: 0.03% or less, sol. Al: 0.005 to 0.1%, and N: 0.01% or less and having a balance of Fe and unavoidable impurities by hot rolling, pickling, cold rolling, then annealing at 650 to 900° C., cooling to 250 to 450° C., holding at said temperature range for 120 seconds or more, then cooling to room temperature, pickling, preplating Ni or Ni—Fe without intermediate temper rolling, heating by 5° C./sec or more down to 430 to 500° C., galvanizing in a galvanization bath, wiping, then heating by a rate of temperature rise of 20° C.Type: ApplicationFiled: March 28, 2007Publication date: June 18, 2009Inventors: Junji Haji, Kaoru Kawasaki, Kiyokazu Ishizuka, Teruaki Yamada