Patents by Inventor Kenji Oi
Kenji Oi 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: 12208462Abstract: A welding process used in a method of manufacturing a steel sheet assembly includes spot welding steel sheets performed for a heat time of 0.08 seconds or more using a convex electrode with a tip radius of curvature of 20 mm or more or a flat electrode such that the weld force F (kN) for initial 0.03 seconds of the heat time satisfies formula: F<0.00125×(1+0.75×tall)+3 where TS (MPa) denotes an average strength of the steel sheets and represents a weighted mean value of a thickness of each of the steel sheets, and tall (mm) denotes a total thickness of the steel sheets (the sum of the thicknesses of the steel sheets).Type: GrantFiled: May 13, 2021Date of Patent: January 28, 2025Assignee: JFE Steel CorporationInventors: Hiroshi Matsuda, Yasuaki Okita, Muneo Matsushita, Rinsei Ikeda, Kenji Oi
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Publication number: 20210260685Abstract: A welding process used in a method of manufacturing a steel sheet assembly includes spot welding steel sheets performed for a heat time of 0.08 seconds or more using a convex electrode with a tip radius of curvature of 20 mm or more or a flat electrode such that the weld force F (kN) for initial 0.03 seconds of the heat time satisfies formula: F<0.00125×(1+0.75×tall)+3 where TS (MPa) denotes an average strength of the steel sheets and represents a weighted mean value of a thickness of each of the steel sheets, and tall (mm) denotes a total thickness of the steel sheets (the sum of the thicknesses of the steel sheets).Type: ApplicationFiled: May 13, 2021Publication date: August 26, 2021Inventors: Hiroshi Matsuda, Yasuaki Okita, Muneo Matsushita, Rinsei Ikeda, Kenji Oi
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Patent number: 10328518Abstract: A method of resistance spot welding to join a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding to store, for each step as a target value, a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume; and subsequently, as actual welding, starting welding using, as a standard, a time variation curve of the instantaneous amount of heat generated per unit volume obtained by the test welding, and when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, performing adaptive control welding to control a current passage amount in order to compensate for the difference during a remaining welding time in the step.Type: GrantFiled: January 24, 2014Date of Patent: June 25, 2019Assignee: JFE STEEL CORPORATIONInventors: Yasuaki Okita, Chikaumi Sawanishi, Rinsei Ikeda, Kenji Oi
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Publication number: 20170348790Abstract: A steel sheet assembly includes a plurality of lapped steel sheets which have a tensile strength of 1,470 MPa or less and a thickness of 0.3 mm to 5.0 mm, the steel sheet assembly being formed by applying, in advance, an adhesive and a carbon-supplying agent to a surface of either or both of the steel sheets to be lapped and then welding the steel sheets. A weld of the assembly has a nugget diameter of 2.8?t (mm) or more, where t (mm) denotes the thickness of a thinner one of the steel sheets on both sides of a weld interface, and the amount of C is increased by 0.02 % by mass or more as compared to the steel sheets before being applied with the adhesive and the carbon-supplying agent.Type: ApplicationFiled: January 22, 2016Publication date: December 7, 2017Inventors: Hiroshi Matsuda, Yasuaki Okita, Muneo Matsushita, Rinsei Ikeda, Kenji Oi
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Patent number: 9677692Abstract: A steel strip is formed into a cylinder so that opposite ends of the steel strip face each other, while continuously conveying the steel strip. The opposite ends are melted across the entire thickness by irradiating the opposite ends with a high-energy-density beam while applying a pressure with squeeze rolls. A seam is formed by joining the opposite ends, and excess weld metal of the seam on the outer and inner sides of the obtained welded steel pipe is removed by cutting. A repaired seam is then formed by remelting and solidifying a region on the inner side of the welded steel pipe, the region having a depth of 0.5 mm or more from the surface and a width of double or more the width of the seam, and in addition, the center line of the seam is made to coincide with the center line of the repaired seam.Type: GrantFiled: January 7, 2015Date of Patent: June 13, 2017Assignee: JFE Steel CorporationInventors: Koji Yano, Kenji Oi
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Patent number: 9364921Abstract: A method of manufacturing a laser welded steel pipe by forming a steel strip into a cylindrical open pipe and performing laser welding on edges that includes: emitting two laser beams along the edges from an upper surface side of the open pipe, the two laser beams being transmitted through different optical fibers with in-focus spot diameters exceeding 0.3 mm; emitting leading and trailing laser beams each inclined toward a direction in which welding proceeds at an incident angle with respect to a direction perpendicular to an upper surface of the open pipe; setting the incident angle of the leading laser beam to be larger than the incident angle of the trailing laser beam; and setting a gap between a center point of the leading laser beam and a center point of the trailing laser beam on a back surface of the open pipe to 1 mm or larger.Type: GrantFiled: April 28, 2011Date of Patent: June 14, 2016Assignee: JFE STEEL CORPORATIONInventors: Koji Yano, Hiroyuki Sumi, Kenji Oi
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Patent number: 9321119Abstract: Provided are a combination welding method and a combination arc welding machine thereof having excellent construction efficiency and preventing a deterioration of toughness of a HAZ by maintaining the current density of each of gas metal arc welding and submerged-arc welding within an appropriate range at the time of welding a steel plate by the combination of the gas metal arc welding using multielectrodes and the submerged-arc welding using multielectrodes. The gas metal arc welding is performed using two or more electrodes, a wire for welding having a wire diameter of 1.4 mm or more is used in the first electrode of the gas metal arc welding, and a current density of the first electrode is set to 320 A/mm2 or more.Type: GrantFiled: February 25, 2010Date of Patent: April 26, 2016Assignee: JFE Steel CorporationInventors: Naoya Hayakawa, Kenji Oi, Atsushi Ishigami, Kenji Shimada, Masahiro Odaka
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Publication number: 20160008913Abstract: Proposed is a method of resistance spot welding to join a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding to store, for each step as a target value, a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume; and subsequently, as actual welding, starting welding using, as a standard, a time variation curve of the instantaneous amount of heat generated per unit volume obtained by the test welding, and when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, performing adaptive control welding to control a current passage amount in order to compensate for the difference during a remaining welding time in the step.Type: ApplicationFiled: January 24, 2014Publication date: January 14, 2016Applicant: JFE STEEL CORPORATIONInventors: Yasuaki OKITA, Chikaumi SAWANISHI, Rinsei IKEDA, Kenji OI
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Publication number: 20150204464Abstract: A steel strip is formed into a cylinder so that opposite ends of the steel strip face each other, while continuously conveying the steel strip. The opposite ends are melted across the entire thickness by irradiating the opposite ends with a high-energy-density beam while applying a pressure with squeeze rolls. A seam is formed by joining the opposite ends, and excess weld metal of the seam on the outer and inner sides of the obtained welded steel pipe is removed by cutting. A repaired seam is then formed by remelting and solidifying a region on the inner side of the welded steel pipe, the region having a depth of 0.5 mm or more from the surface and a width of double or more the width of the seam, and in addition, the center line of the seam is made to coincide with the center line of the repaired seam.Type: ApplicationFiled: January 7, 2015Publication date: July 23, 2015Applicant: JFE Steel CorporationInventors: Koji Yano, Kenji Oi
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Patent number: 8993920Abstract: A steel strip is formed into a cylinder so that opposite ends of the steel strip face each other, while continuously conveying the steel strip. The opposite ends are melted across the entire thickness by irradiating the opposite ends with a high-energy-density beam while applying a pressure with squeeze rolls. A seam is formed by joining the opposite ends, and excess weld metal of the seam on the outer and inner sides of the obtained welded steel pipe is removed by cutting. A repaired seam is then formed by remelting and solidifying a region on the inner side of the welded steel pipe, the region having a depth of 0.5 mm or more from the surface and a width of double or more the width of the seam, and in addition, the center line of the seam is made to coincide with the center line of the repaired seam.Type: GrantFiled: March 30, 2009Date of Patent: March 31, 2015Assignee: JFE Steel CorporationInventors: Koji Yano, Kenji Oi
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Patent number: 8955554Abstract: Provided is a submerged arc welding method for a steel plate. In welding the steel plate from an internal surface or an external surface by a submerged arc welding, welding condition is set such that, a cross-sectional area of internal weld metal S1 and a cross-sectional area of external weld metal S2 satisfy the formula (1), the formula (2), and the formula (3), that is, 0.40?(S1+S2)/t2?0.80 . . . (1), S1/t2?0.35 . . . (2), and S2/t2?0.45 . . . (3), wherein t is a plate thickness of the steel plate (mm), S1 is a cross-sectional area of the internal weld metal (mm2) excluding the cross-sectional area of a portion of the internal weld metal overlapping with the external weld metal after external welding, and S2 is a cross-sectional area of the external weld metal (mm2).Type: GrantFiled: September 4, 2009Date of Patent: February 17, 2015Assignee: JFE Steel CorporationInventors: Atsushi Ishigami, Kenji Oi, Naoya Hayakawa
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Patent number: 8785806Abstract: Steel is subjected to multiple-electrode submerged arc welding with three or more electrodes in which a direct-current power source is used to supply current to a first electrode, the welding by the first electrode is carried out at a current density of 250 A/mm2 or more, preferably with a wire diameter of 3.2 mm or less and a weld current of 1,000 A or more, the welding by the second electrode is carried out at a current density of 150 A/mm2 or more, preferably with a weld current of 600 A or more, one of the interelectrode spacings is 23 mm or more on a surface of the steel, and the remaining interelectrode spacings are 20 mm or less.Type: GrantFiled: February 19, 2009Date of Patent: July 22, 2014Assignee: JFE Steel CorporationInventors: Atsushi Ishigami, Kenji Oi, Naoya Hayakawa
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Publication number: 20140175069Abstract: Provided is a method of efficiently manufacturing a high-quality laser welded steel pipe at a high yield ratio while occurrence of underfill is prevented. Specifically, welding is performed using multiple laser beams each having a spot diameter of 0.3 mm or larger on an upper surface of an open pipe (a surface of a steel strip), the plurality of laser beams being arranged such that the sum of spot lengths of the plurality of laser beams, the spot lengths extending perpendicularly to a welding line, on the surface of the steel strip is 0.5 mm or larger and such that a distance between spot centers of the plurality of laser beams in a direction of the welding line falls within 5 mm.Type: ApplicationFiled: April 28, 2011Publication date: June 26, 2014Applicant: JFE Steel CorporationInventors: Koji Yano, Kenji Oi
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Patent number: 8728257Abstract: The invention provides a high tensile strength steel material having a tensile strength of 600 MPa, which is excellent in delayed fracture resistance property, and a method of manufacturing the steel material. As means for this, a steel material contains, in mass percent, C of 0.02 to 0.25%, Si of 0.01 to 0.8%, Mn of 0.5 to 2.0%, Al of 0.005 to 0.1%, N of 0.0005 to 0.008%, P of 0.03% or less, and S of 0.03% or less. In addition, the steel material contains at least one element selected from Mo, Nb, V, and Ti, and contains at least one of Cu, Ni, Cr, W, B, Ca, REM and Mg, as needed. The remainder includes Fe and inevitable impurities. In addition, in the steel material, precipitates having an average grain size of 20 nm or less, which contains at least one of Mo, Nb, V and Ti, are contained in steel in the number of at least 5 per 250000 nm2, and a microstructure includes residual austenite in a volume fraction of 0.5 to 5%. When Ca to be added is specified to be 0.0010% to 0.Type: GrantFiled: May 29, 2006Date of Patent: May 20, 2014Assignee: JFE Steel CorporationInventors: Kenji Oi, Akihide Nagao, Kenji Hayashi
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Publication number: 20140124481Abstract: A method of manufacturing a laser welded steel pipe by forming a steel strip into a cylindrical open pipe and performing laser welding on edges that includes: emitting two laser beams along the edges from an upper surface side of the open pipe, the two laser beams being transmitted through different optical fibers with in-focus spot diameters exceeding 0.3 mm; emitting leading and trailing laser beams each inclined toward a direction in which welding proceeds at an incident angle with respect to a direction perpendicular to an upper surface of the open pipe; setting the incident angle of the leading laser beam to be larger than the incident angle of the trailing laser beam; and setting a gap between a center point of the leading laser beam and a center point of the trailing laser beam on a back surface of the open pipe to 1 mm or larger.Type: ApplicationFiled: April 28, 2011Publication date: May 8, 2014Applicant: JFE STEEL CORPORATIONInventors: Koji Yano, Hiroyuki Sumi, Kenji Oi
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Patent number: 8604382Abstract: There is provided a method for manufacturing a laser welded steel pipe in which the status of laser welding is accurately assessed, and the assessment is used to modify welding conditions, so that laser welded steel pipes can be manufactured at a high yield rate and in a stable manner. Irradiation point(s) of laser beam(s), with which the longitudinal edges are irradiated from the side of the outer surface, are monitored from the side of the inner surface of an open pipe, and then conditions of welding with the laser beam(s) are assessed to be kept unchanged if any keyhole is found penetrating out of the inner surface of the open pipe, or modified if no keyhole is found penetrating out of the inner surface of the open pipe.Type: GrantFiled: June 22, 2009Date of Patent: December 10, 2013Assignee: JFE Steel CorporationInventors: Koji Yano, Kenji Oi, Masahito Suzuki, Toshifumi Kodama, Shigeto Sakashita
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Patent number: 8357252Abstract: High tensile strength steels that have both favorable delayed fracture resistance and a tensile strength of 600 MPa or higher and are suitably used in construction machinery, tanks, penstocks, and pipelines, as well as methods for manufacturing such steels are provided. The safety index of delayed fracture resistance (%) is 100×(X1/X0), where X0: reduction of area of a specimen substantially free from diffusible hydrogen, and X1: reduction of area of a specimen containing diffusible hydrogen.Type: GrantFiled: January 31, 2008Date of Patent: January 22, 2013Assignee: JFE Steel CorporationInventors: Akihide Nagao, Kenji Oi, Kenji Hayashi, Nobuo Shikanai
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Publication number: 20120325362Abstract: Provided is a submerged arc welding method for a steel plate. In welding the steel plate from an internal surface or an external surface by a submerged arc welding, welding condition is set such that, a cross-sectional area of internal weld metal S1 and a cross-sectional area of external weld metal S2 satisfy the formula (1), the formula (2), and the formula (3), that is, 0.40?(S1+S2)/t2?0.80 . . . (1), S1/t2?0.35 . . . (2), and S2/t2?0.45 . . . (3), wherein t is a plate thickness of the steel plate (mm), S1 is a cross-sectional area of the internal weld metal (mm2) excluding the cross-sectional area of a portion of the internal weld metal overlapping with the external weld metal after external welding, and S2 is a cross-sectional area of the external weld metal (mm2).Type: ApplicationFiled: September 4, 2009Publication date: December 27, 2012Applicant: JFE STEEL CORPORATIONInventors: Atsushi Ishigami, Kenji Oi, Naoya Hayakawa
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Patent number: 8220632Abstract: A packaged absorbent product including at least one absorbent article having a body surface and a garment surface. The package includes a transparent film layer and a non-white color layer disposed on the transparent film layer. The package has an opacity of 5-55%, and a speculum gloss of 0.1-90.Type: GrantFiled: April 27, 2007Date of Patent: July 17, 2012Assignee: The Procter & Gamble CompanyInventors: Kenji Oi, Nobuyuki Miki
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Publication number: 20120024822Abstract: Provided are a combination welding method and a combination arc welding machine thereof having excellent construction efficiency and preventing a deterioration of toughness of a HAZ by maintaining the current density of each of gas metal arc welding and submerged-arc welding within an appropriate range at the time of welding a steel plate by the combination of the gas metal arc welding using multielectrodes and the submerged-arc welding using multielectrodes. The gas metal arc welding is performed using two or more electrodes, a wire for welding having a wire diameter of 1.4 mm or more is used in the first electrode of the gas metal arc welding, and a current density of the first electrode is set to 320 A/mm2 or more.Type: ApplicationFiled: February 25, 2010Publication date: February 2, 2012Applicant: JFE STEEL CORPORATIONInventors: Naoya Hayakawa, Kenji Oi, Atsushi Ishigami, Kenji Shimada, Masahiro Odaka