Patents by Inventor Naoki Mizuta

Naoki Mizuta 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: 11426929
    Abstract: Provided is a powder material for producing a three-dimensional object including: a base material; a resin; and resin particles, wherein an amount W (mass %) of carbon remaining in the powder material after heating in a vacuum of 10?2 Pa or lower at 450 degrees C. for 2 hours satisfies the following formula: W (mass %)<0.9/M, where M represents the specific gravity of the base material.
    Type: Grant
    Filed: July 1, 2020
    Date of Patent: August 30, 2022
    Assignee: RICOH COMPANY, LTD.
    Inventors: Junjiroh Sogame, Kohsuke Miyazaki, Takumi Yokoyama, Shinichiroh Satoh, Takafumi Sasaki, Osamu Mizuta, Hiroyuki Miyata, Naoki Oya
  • Publication number: 20220250131
    Abstract: To establish a method for obtaining a hot-press-formed steel member, which exhibits high strength, high tensile elongation (ductility) and high bendability, thereby having excellent deformation characteristics at the time of collision crush (crashworthiness), and which is capable of ensuring excellent delayed fracture resistance. A method for producing a hot-press-formed steel member by heating a steel sheet, which has a chemical component composition containing 0.10% (% by mass, and hereinafter the same shall apply) to 0.30% (inclusive) of C, 1.0% to 2.5% (inclusive) of Si, 1.0% to 3.0% (inclusive) of Si and Al in total and 1.5% to 3.0% (inclusive) of Mn, with the balance consisting of iron and unavoidable impurities, and hot press forming the steel sheet one or more times.
    Type: Application
    Filed: April 25, 2022
    Publication date: August 11, 2022
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takayuki YAMANO, Jiro IWAYA, Noriyuki JIMBO, Tatsuya ASAI, Naoki MIZUTA
  • Patent number: 11365466
    Abstract: Provided is a method for manufacturing a steel member through hot press forming using a steel sheet that contains a comparatively large amount of Si. The steel sheet includes, in mass ratio, C: 0.15% to 0.35%, Si: 1.0% to 3.0%, Mn: 1.0% to 3.0%, Al: more than 0% up to 0.10%, Ti: ([N]×48/14)% to 0.10% (where [N] denotes the amount of N in the steel sheet), B: 5 ppm to 50 ppm, P: more than 0% to less than 0.015%, S: more than 0% up to 0.010%, and N: more than 0% up to 0.010%, the balance being iron and unavoidable impurities. The average oxygen concentration from an outermost surface of the steel sheet down to a depth of 10 ?m in a sheet thickness direction is 0.70 mass % or higher.
    Type: Grant
    Filed: November 25, 2019
    Date of Patent: June 21, 2022
    Assignee: Kobe Steel, Ltd.
    Inventors: Tatsuya Asai, Naoki Mizuta, Hiroyuki Omori, Takeshi Kojima
  • Patent number: 11344941
    Abstract: In a method for obtaining a hot-press-formed steel member, a steel sheet containing 0.10-0.30 mass % of C, 1.0-2.5 mass % of Si, 1.0-3.0 mass % of Si and Al in total, and 1.5-3.0 mass % of Mn is heated at a heating temperature of not less than the Ac3 transformation point. The steel sheet is hot-press formed for one or more times. The starting temperature of the hot pressing is not more than the heating temperature but not less than the Ms point. The average cooling rate from (Ms point?150)° C. to 40° C. is 5° C./s or less. The hot-press-formed steel member has high strength, high tensile elongation, high bendability, excellent deformation characteristics at the time of collision crush, and excellent delayed fracture resistance.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: May 31, 2022
    Assignee: Kobe Steel, Ltd.
    Inventors: Takayuki Yamano, Jiro Iwaya, Noriyuki Jimbo, Tatsuya Asai, Naoki Mizuta
  • Publication number: 20200095660
    Abstract: Provided is a method for manufacturing a steel member through hot press forming using a steel sheet that contains a comparatively large amount of Si. The steel sheet includes, in mass ratio, C: 0.15% to 0.35%, Si: 1.0% to 3.0%, Mn: 1.0% to 3.0%, Al: more than 0% up to 0.10%, Ti: ([N]×48/14)% to 0.10% (where [N] denotes the amount of N in the steel sheet), B: 5 ppm to 50 ppm, P: more than 0% to less than 0.015%, S: more than 0% up to 0.010%, and N: more than 0% up to 0.010%, the balance being iron and unavoidable impurities. The average oxygen concentration from an outermost surface of the steel sheet down to a depth of 10 ?m in a sheet thickness direction is 0.70 mass % or higher.
    Type: Application
    Filed: November 25, 2019
    Publication date: March 26, 2020
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Tatsuya Asai, Naoki Mizuta, Hiroyuki Omori, Takeshi Kojima
  • Patent number: 10544489
    Abstract: A high-strength steel sheet has a chemical composition including 0.05% to 0.3% of C, 1% to 3% of Si, 0.5% to 3% of Mn, 0% to 0.1% of P, 0.001% to 0.1% of Al, and 0.002% to 0.03% of N, in mass percent; further includes iron and impurities; and has a structure including 50% to 90% of bainitic ferrite, 5% to 20% of retained austenite (?R), a total of 10% to 50% of martensite and the retained austenite, and 0% to 40% of polygonal ferrite, in area percent based on the entire structure. The retained austenite has a carbon content (C?R) of 0.5% to 1.2% by mass, an average equivalent circle diameter of 0.2 to 2 ?m, and an average aspect ratio (maximum diameter/minimum diameter) of less than 3.0. The high-strength steel sheet excels both in elongation and deep drawability while having a strength of 980 MPa or more.
    Type: Grant
    Filed: November 16, 2011
    Date of Patent: January 28, 2020
    Assignee: Kobe Steel, Ltd.
    Inventors: Elijah Kakiuchi, Toshio Murakami, Hideo Hata, Tatsuya Asai, Naoki Mizuta
  • Patent number: 9890437
    Abstract: This high-strength steel sheet contains, in mass %, 0.05 to 0.3% of C, 1 to 3% of Si, 0.5 to 3% of Mn, up to 0.1% (inclusive of 0%) of P, up to 0.01% (inclusive of 0%) of S, 0.001 to 0.1% of Al and 0.002 to 0.03% of N with the balance consisting of iron and unavoidable impurities, and has a microstructure which comprises, in area fraction relative to the microstructure, 40 to 85% of bainitic ferrite, 5 to 20% of retained austenite (?R), 10 to 50% (in total) of martensite and ?R, and 5 to 40% of ferrite. The retained austenite (?R) has a C concentration of 0.5 to 1.0 mass %, while the quantity of ?R present in the ferrite grains is 1% or more (in area fraction) relative to the microstructure.
    Type: Grant
    Filed: February 6, 2013
    Date of Patent: February 13, 2018
    Assignee: Kobe Steel, Ltd.
    Inventors: Elijah Kakiuchi, Toshio Murakami, Katsura Kajihara, Tatsuya Asai, Naoki Mizuta, Hideo Hata
  • Publication number: 20180029102
    Abstract: A steel sheet for hot pressing which contains, in mass %, C: 0.15% or more to 0.40% or less, Si: 1.00% or more to 2.00% or less, Mn: 1.50% or more to 3.00% or less, Ti: (N×48/14)% or more to 0.10% or less, B: 0.0005% or more to 0.0050% or less, Al: more than 0% to 0.10% or less, P: more than 0% to 0.05% or less, S: more than 0% to 0.01% or less, N: more than 0% to 0.010% or less, iron and inevitable impurities. This steel sheet for hot pressing is also characterized by having a dislocation density of 10×1014/m2 or more, an area ratio of pearlite relative to the whole structure being 30% or more, and a tensile strength of 1100 MPa or less.
    Type: Application
    Filed: March 11, 2016
    Publication date: February 1, 2018
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Hiroyuki OMORI, Naoki MIZUTA, Tatsuya ASAI
  • Patent number: 9863028
    Abstract: A hot-dip galvanized steel sheet contains specific amounts of C, Si, Mn, P, S, Ti, Al, and N with the remainder being iron and unavoidable impurities. Bainitic ferrite, martensite, retained ?, and ferrite (?) are present each in a specific area ratio. The remainder ? has a specific C concentration. Sub-grains in the recrystallized ? and un-recrystallized ? have a specific grain diameter. The surface area ratio of ? and worked ? having a grain diameter of 5 ?m or more is 5% or less. The average particle diameter of TiC particles inside ? grains is 10 nm or less.
    Type: Grant
    Filed: June 26, 2013
    Date of Patent: January 9, 2018
    Assignee: Kobe Steel, Ltd.
    Inventors: Elijah Kakiuchi, Toshio Murakami, Katsura Kajihara, Tatsuya Asai, Naoki Mizuta
  • Patent number: 9657381
    Abstract: This high-strength steel plate has a component composition including, by mass %, C: 0.02-0.3%, Si: 1-3%, Mn: 1.8-3%, P: 0.1% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.002-0.03%, the rest consisting of iron and impurities. Said steel plate has a microstructure including, in terms of area ratio relative to the entire microstructure, each of the following phases: bainitic ferrite: 50-85%; retained ?: 3% or greater; martensite+the aforementioned retained ?: 10-45%; and ferrite: 5-40%. The C concentration (C?R) in the aforementioned retained austenite is 0.3-1.2 mass %, part or all of the N in the aforementioned component composition is solid solution N, and the amount of said solid solution N is 30-100 ppm.
    Type: Grant
    Filed: August 15, 2012
    Date of Patent: May 23, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Toshio Murakami, Elijah Kakiuchi, Hideo Hata, Naoki Mizuta, Tatsuya Asai
  • Patent number: 9550221
    Abstract: A press forming method forming an extended part by extension in a later forming period after deep drawing, the deep drawing process carried out with working at 100-250° C., and the extension forming process carried out colder at less than 50° C., whereby the extended part is formed by extension in a cup shaped low parts formed by deep drawing. Thus, press forming products containing formed elements can be deep drawing formed and extension formed at a high forming rate of 10 mm/sec or greater, which can assure high productivity. By making a steel plate temperature 100-350° C. during press forming and by making the forming rate in the later forming period where extension forming is carried out slower than the forming rate in an earlier forming period where extension forming is not carried out, cracking of the extended part can be prevented and press forming limitations can be improved.
    Type: Grant
    Filed: February 23, 2016
    Date of Patent: January 24, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Takayuki Yamano, Jiro Iwaya, Takayuki Kimura, Tatsuya Asai, Naoki Mizuta
  • Publication number: 20160319403
    Abstract: Provided is a method for manufacturing a steel member through hot press forming using a steel sheet that contains a comparatively large amount of Si. The method allows hot press forming to be carried out satisfactorily by stably and reliably suppressing shedding/peeling of oxide scale during hot press forming, even without restricting hot press forming conditions to a narrow range. The steel sheet includes, in mass ratio, C: 0.15% to 0.35%, Si: 1.0% to 3.0%, Mn: 1.0% to 3.0%, Al: more than 0% up to 0.10%, Ti: ([N]×48/14) % to 0.10% (where [N] denotes the amount of N in the steel sheet), B: 5 ppm to 50 ppm, P: more than 0% to less than 0.015%, S: more than 0% up to 0.010%, and N: more than 0% up to 0.010%, the balance being iron and unavoidable impurities. The average oxygen concentration from an outermost surface of the steel sheet down to a depth of 10 ?m in a sheet thickness direction is 0.70 mass % or higher.
    Type: Application
    Filed: December 22, 2014
    Publication date: November 3, 2016
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Tatsuya ASAI, Naoki MIZUTA, Hiroyuki OMORI, Takeshi KOJIMA
  • Patent number: 9463501
    Abstract: A press forming method forming an extended part by extension in a later forming period after deep drawing, the deep drawing process carried out with working at 100-250° C., and the extension forming process carried out colder at less than 50° C., whereby the extended part is formed by extension in a cup shaped low parts formed by deep drawing. Thus, press forming products containing formed elements can be deep drawing formed and extension formed at a high forming rate of 10 mm/sec or greater, which can assure high productivity. By making a steel plate temperature 100-350° C. during press forming and by making the forming rate in the later forming period where extension forming is carried out slower than the forming rate in an earlier forming period where extension forming is not carried out, cracking of the extended part can be prevented and press forming limitations can be improved.
    Type: Grant
    Filed: January 12, 2012
    Date of Patent: October 11, 2016
    Assignee: Kobe Steel, Ltd.
    Inventors: Takayuki Yamano, Jiro Iwaya, Takayuki Kimura, Tatsuya Asai, Naoki Mizuta
  • Publication number: 20160214161
    Abstract: A press forming method forming an extended part by extension in a later forming period after deep drawing, the deep drawing process carried out with working at 100-250° C., and the extension forming process carried out colder at less than 50° C., whereby the extended part is formed by extension in a cup shaped low parts formed by deep drawing. Thus, press forming products containing formed elements can be deep drawing formed and extension formed at a high forming rate of 10 mm/sec or greater, which can assure high productivity. By making a steel plate temperature 100-350° C. during press forming and by making the forming rate in the later forming period where extension forming is carried out slower than the forming rate in an earlier forming period where extension forming is not carried out, cracking of the extended part can be prevented and press forming limitations can be improved.
    Type: Application
    Filed: February 23, 2016
    Publication date: July 28, 2016
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takayuki YAMANO, Jiro IWAYA, Takayuki KIMURA, Tatsuya ASAI, Naoki MIZUTA
  • Patent number: 9359663
    Abstract: Provided is a method for manufacturing a hot press formed steel member that has high strengths, an excellent balance between strength and ductility, and good deformation properties upon crush on collision (crashworthiness). The manufacturing method is highly efficient and allows a high degree of freedom with respect to the shape to be formed. The method manufactures a steel member by heating a steel sheet having a specific chemical composition and subjecting the steel sheet to at least one time of hot press forming. In the method, the heating temperature is equal to or higher than the Ac3 transformation temperature, and a starting temperature of the hot press forming is in the range from the heating temperature to martensite start (Ms) temperature. Cooling from [(Ms temperature)?150° C.] down to 80° C. is performed so that a tempering parameter (?) specified by Expression (1) is in the range from 7100 to 8030.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: June 7, 2016
    Assignee: Kobe Steel, Ltd.
    Inventors: Naoki Mizuta, Tatsuya Asai, Takayuki Yamano, Tetsuji Hoshika
  • Publication number: 20150354035
    Abstract: Provided is a method for manufacturing a hot press formed steel member that has high strengths, an excellent balance between strength and ductility, and good deformation properties upon crush on collision (crashworthiness). The manufacturing method is highly efficient and allows a high degree of freedom with respect to the shape to be formed. The method manufactures a steel member by heating a steel sheet having a specific chemical composition and subjecting the steel sheet to at least one time of hot press forming. In the method, the heating temperature is equal to or higher than the Ac3 transformation temperature, and a starting temperature of the hot press forming is in the range from the heating temperature to martensite start (Ms) temperature. Cooling from [(Ms temperature)?150° C.] down to 80° C. is performed so that a tempering parameter (?) specified by Expression (1) is in the range from 7100 to 8030.
    Type: Application
    Filed: January 17, 2014
    Publication date: December 10, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)
    Inventors: Naoki MIZUTA, Tatsuya ASAI, Takayuki YAMANO, Tetsuji HOSHIKA
  • Patent number: 9194032
    Abstract: This high-strength steel sheet has a component composition containing, in mass %, 0.02 to 0.3% C, 1 to 3% Si, 1.8 to 3% Mn, 0.1% or less P, 0.01% or less S, 0.001 to 0.1% Al, and 0.002 to 0.03% N, the remainder being iron and impurities. The high-strength steel sheet has a structure containing, in terms of area ratio relative to the entire structure, each of the following phases: 50 to 85% bainitic ferrite; 3% or more retained austenite (?); 10 to 45% martensite and the aforementioned retained austenite (?); and 5 to 40% ferrite. The ratio between the Mn concentration (Mn?R) in the retained austenite (?) and the average Mn concentration (Mnav) in the entire structure is 1.2 or more (Mn?R/ Mnav) based on the Mn concentration distribution obtained by means of EPMA line analysis. As a consequence, the high-strength steel sheet exhibits strength of 980 MPa or more and exerts excellent deep drawability.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: November 24, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Toshio Murakami, Elijah Kakiuchi, Hideo Hata, Tatsuya Asai, Naoki Mizuta
  • Publication number: 20150184274
    Abstract: A hot-dip galvanized steel sheet contains specific amounts of C, Si, Mn, P, S, Ti, Al, and N with the remainder being iron and unavoidable impurities. Bainitic ferrite, martensite, retained ?, and ferrite (?) are present each in a specific area ratio. The remainder ? has a specific C concentration. Sub-grains in the recrystallized ? and un-recrystallized ? have a specific grain diameter. The surface area ratio of ? and worked ? having a grain diameter of 5 ?m or more is 5% or less. The average particle diameter of TiC particles inside a grains is 10 nm or less.
    Type: Application
    Filed: June 26, 2013
    Publication date: July 2, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Elijah Kakiuchi, Toshio Murakami, Katsura Kajihara, Tatsuya Asai, Naoki Mizuta
  • Publication number: 20150000796
    Abstract: This high-strength steel sheet contains, in mass %, 0.05 to 0.3% of C, 1 to 3% of Si, 0.5 to 3% of Mn, up to 0.1% (inclusive of 0%) of P, up to 0.01% (inclusive of 0%) of S, 0.001 to 0.1% of Al and 0.002 to 0.03% of N with the balance consisting of iron and unavoidable impurities, and has a microstructure which comprises, in area fraction relative to the microstructure, 40 to 85% of bainitic ferrite, 5 to 20% of retained austenite (?R), 10 to 50% (in total) of martensite and ?R, and 5 to 40% of ferrite. The retained austenite (?R) has a C concentration of 0.5 to 1.0 mass %, while the quantity of ?R present in the ferrite grains is 1% or more (in area fraction) relative to the microstructure.
    Type: Application
    Filed: February 6, 2013
    Publication date: January 1, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Elijah Kakiuchi, Toshio Murakami, Katsura Kajihara, Tatsuya Asai, Naoki Mizuta, Hideo Hata
  • Publication number: 20140271331
    Abstract: This high-strength steel plate has a component composition including, by mass %, C: 0.02-0.3%, Si: 1-3%, Mn: 1.8-3%, P: 0.1% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.002-0.03%, the rest consisting of iron and impurities. Said steel plate has a microstructure including, in terms of area ratio relative to the entire microstructure, each of the following phases: bainitic ferrite: 50-85%; retained ?; 3% or greater; martensite+the aforementioned retained ?; 10-45%; and ferrite: 5-40%. The C concentration (C?R) in the aforementioned retained austenite is 0.3-1.2 mass %, part or all of the N in the aforementioned component composition is solid solution N, and the amount of said solid solution N is 30-100 ppm.
    Type: Application
    Filed: August 15, 2012
    Publication date: September 18, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Elijah Kakiuchi, Hideo Hata, Naoki Mizuta, Tatsuya Asai