Beryllium Or Boron Containing Patents (Class 148/330)
  • Patent number: 11959158
    Abstract: A low-carbon and low alloy hot-work die steel with a high toughness at low temperatures and a high strength at high temperatures and a high hardenability, comprises the following components: C: 0.15-0.35%, Si: 0.40-0.90%, Mn: ?0.80%, Cr: 1.50-2.40%, Ni: 2.50-4.50%, Mo: 1.00-1.60%, V: 0.10-0.40%, W: 0.20-0.90%, P: ?0.02%, S?0.02%, and a balance of Fe matrix and other inevitable impurities. The above percentages are mass percentages. The material of the present invention can have a V notch impact energy of 30 J or more than 30 J at ?40° C., a high temperature strength of 380 MPa or more at 700° C., and a hardenability of 200 mm or more to ensure the consistency of internal and external microstructures. The materials of the present invention can be applied to hot-work molds used in special working conditions that require high toughness at low temperatures, high strength at high temperatures and high hardenability.
    Type: Grant
    Filed: October 14, 2021
    Date of Patent: April 16, 2024
    Assignee: University of Science & Technology Beijing
    Inventors: Jinfeng Huang, Jin Zhang, Chao Zhao, Cheng Zhang
  • Patent number: 11939651
    Abstract: Provided is an Al—Fe-alloy plated steel sheet for hot forming, having excellent TWB welding characteristics since excellent hardness uniformity of a TWB weld zone after hot forming is obtained by suitably controlling a batch annealing condition, after plating Al, such that an Al—Fe-alloy layer is formed; a hot forming member; and manufacturing methods therefor.
    Type: Grant
    Filed: May 31, 2018
    Date of Patent: March 26, 2024
    Assignee: POSCO CO., LTD
    Inventors: Seong-Woo Kim, Jin-Keun Oh, Yeol-Rae Cho, Hyeon-Jeong Shin
  • Patent number: 11939640
    Abstract: A method for producing a hot-rolled steel sheet, a method for producing a cold-rolled full-hard steel sheet, and a method for producing a heat-treated sheet are provided herein. The methods comprising hot rolling a steel material of a composition comprising, in mass %, C: 0.05 to 0.12%, Si: 0.80% or less, Mn: 1.30 to 2.10%, P: 0.001 to 0.050%, S: 0.005% or less, Al: 0.01 to 0.10%, N: 0.010% or less, one or more selected from Cr in an amount of 0.05 to 0.50%, and Mo in an amount of 0.05 to 0.50%, one or more selected from Ti in an amount of 0.01 to 0.10%, Nb in an amount of 0.01 to 0.10%, and V in an amount of 0.01 to 0.10%, and the balance Fe and unavoidable impurities.
    Type: Grant
    Filed: February 18, 2021
    Date of Patent: March 26, 2024
    Assignee: JFE Steel Corporation
    Inventors: Katsutoshi Takashima, Yoshimasa Funakawa
  • Patent number: 11926881
    Abstract: A high-strength cold-rolled steel sheet having a high yield ratio and excellent stretch flangeability and a method for manufacturing the steel sheet. The high-strength cold-rolled steel sheet has a chemical composition including, by mass %, C: 0.10 to 0.30%, Si: 0.50 to 2.00%, Mn: 2.5 to 4.0%, P: 0.050% or less, S: 0.020% or less, Al: 0.10% or less, N: 0.01% or less, Ti: 0.100% or less, and B: 0.0003 to 0.0030%, with the balance being Fe and incidental impurities. N and Ti satisfy a specified formula, and the total area fraction of martensite and bainite is 95% or more. The number density of bainite grains having an area of 3 ?m2 or more and a carbon concentration of less than 0.7C is 1200 grains/mm2 or less.
    Type: Grant
    Filed: June 19, 2020
    Date of Patent: March 12, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Yuji Tanaka, Hidekazu Minami, Naoki Takayama, Takako Yamashita
  • Patent number: 11920208
    Abstract: A cold-rolled and heat-treated steel sheet, has a composition comprising, by weight percent: n0.10%?C?0.25%, 3.5%?Mn—?6.0%, 0.5%?Si?2.0%, 0.3%?Al?1.2%, with Si+Al?0.8%, 0.10%?Mo?0.50%, S?0.010%, P?0.020%, N?0.008%. The cold-rolled steel sheet has a microstructure consisting of, in surface fraction: between 10% and 45% of ferrite, having an average grain size of at most 1.3 ?m, the product of the surface fraction of ferrite by the average grain size of the ferrite being of at most 35 ?m %, between 8% and 30% of retained austenite, the retained austenite having an Mn content higher than 1.1*Mn %, Mn % designating the Mn content of the steel, at most 8% of fresh martensite, at most 2.5% of cementite and partitioned martensite.
    Type: Grant
    Filed: December 18, 2018
    Date of Patent: March 5, 2024
    Assignee: ARCELORMITTAL
    Inventors: Coralie Jung, Astrid Perlade, Kangying Zhu, Frédéric Kegel
  • Patent number: 11920207
    Abstract: A cold rolled heat treated steel sheet having a composition with the following elements, expressed in percentage by weight 0.1%?Carbon?0.5%, 1%?Manganese?3.4%, 0.5%?Silicon?2.5%, 0.03%?Aluminum?1.5%, 0%?Sulfur?0.003%, 0.002%?Phosphorus?0.02%, 0%?Nitrogen?0.01% and can contain one or more of the following optional elements 0.05%?Chromium?1%, 0.001%?Molybdenum?0.5%, 0.001%?Niobium?0.1%, 0.001%?Titanium?0.1%, 0.01%?Copper?2%, 0.01%?Nickel?3%, 0.0001%?Calcium?0.005%, 0%?Vanadium?0.1%, 0%?Boron?0.003%, 0%?Cerium?0.1%, 0%?Magnesium?0.010%, 0%?Zirconium?0.010%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet having in area fraction, 10 to 30% Residual Austenite, 50 to 85% Bainite, 1 to 20% Quenched Martensite, and less than 30% Tempered Martensite.
    Type: Grant
    Filed: November 5, 2018
    Date of Patent: March 5, 2024
    Assignee: ArcelorMittal
    Inventors: Jean-Marc Pipard, Artem Arlazarov
  • Patent number: 11821063
    Abstract: A high-strength steel allowing low-temperature welding and high-heat input welding and a production method thereof are provided, which belongs to the technical field of steel production. The high-strength steel includes the following chemical components by mass fraction: 0.03-0.16% of C, 0.05-0.5% of Si, 1.0-1.9% of Mn, 0.002-0.02% of P, 0.001-0.01% of S, 0.005-0.07% of Al, 0.005-0.04% of Ti, 0.1-0.5% of Cr, 0.0005-0.005% of B, 0.002-0.01% of Mg+Zr, 0.001-0.008% of O, 0.004-0.01% of N, and the balance of Fe and residual elements. Magnesium and zirconium are added to form magnesium/zirconium oxide, titanium and boron are added to form titanium/boron nitride, and the two types of precipitates work synergistically to improve the microstructure of a heat-affected zone. The method optimizes the chemical composition and production process of existing high-strength steel.
    Type: Grant
    Filed: July 29, 2022
    Date of Patent: November 21, 2023
    Assignee: NORTHEASTERN UNIVERSITY
    Inventors: Chao Wang, Junjie Hao, Guo Yuan, Jian Kang, Zhenlei Li, Guodong Wang
  • Patent number: 11819909
    Abstract: The method for manufacturing a high-manganese steel cast slab according to the present invention includes manufacturing a cast slab by continuously casting a molten high-manganese steel having a specific chemical composition. In the manufacture, in a continuous-casting machine or during transportation before subsequent charging into a heating furnace for hot rolling, a processing strain is applied to the cast slab having a surface temperature of 600° C. or higher and 1100° C. or lower in such an amount that a processing strain amount calculated by a certain formula is 3.0% or more and 10.0% or less.
    Type: Grant
    Filed: January 22, 2020
    Date of Patent: November 21, 2023
    Assignee: JFE STEEL CORPORATION
    Inventors: Yoichi Ito, Norichika Aramaki, Koichi Nakashima, Shigeki Kitsuya
  • Patent number: 11634802
    Abstract: The cold-rolled steel sheet having a high bake hardening amount and excellent bendability after bake hardening according to the present invention has a predetermined composition, and contains 20% or more and 70% or less of ferrite and 30% or more of tempered martensite in terms of area ratio, in which a sum of ferrite and tempered martensite is 90% or more, and in a case where a microstructure image of 30 ?m×30 ?m obtained by photographing a structure at a magnification of 2,000-fold is disposed in an xy coordinate system having a sheet thickness direction as an x-axis and a rolling direction as a y-axis, the microstructure image is divided into 1024 pieces in an x-axis direction and 1024 pieces in a y-axis direction to form 1024×1024 divided regions, and a two-dimensional image is created by performing double gradation by assuming a value of “1” in each of the divided regions in one case where the structure is ferrite and assuming a value of “0” in the other cases, a heterogeneity ? when two-dimensional disc
    Type: Grant
    Filed: October 4, 2019
    Date of Patent: April 25, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hiroshi Kaido, Mai Nagano, Koutarou Hayashi
  • Patent number: 11555228
    Abstract: The present invention relates to an amorphous alloy corresponding to the formula: CoaNibMoc(C1-xBx)dXe wherein X is one or several elements selected from the group consisting of Cu, Si, Fe, P, Y, Er, Cr, Ga, Ta, Nb, V and W; wherein the indices a to e and x satisfy the following conditions: 55?a?75 at. % 0?b?15 at. % 7?c?17 at. % 15?d?23 at. % 0.1?x?0.9 at. % 0?e?10 at. %, each element selected from the group having a content?3 at. % and preferably ?2 at. %, the balance being impurities.
    Type: Grant
    Filed: November 29, 2019
    Date of Patent: January 17, 2023
    Assignee: The Swatch Group Research and Development Ltd.
    Inventors: Alban Dubach, David Ehinger, Mihai Stoica
  • Patent number: 11505855
    Abstract: What is provided is a high-strength steel sheet including, by mass %: C: 0.05% to 0.15%; Si: 1.5% or less; Mn: 2.00% to 5.00%; P: 0.100% or less; S: 0.010% or less; Al: 0.001% to 2.000%; N: 0.010% or less; and a remainder of Fe and impurities, in which Ceq defined by Ceq=C+Si/90+Mn/100+1.5P+3S is less than 0.21, the high-strength steel sheet contains martensite in an area ratio of 98% or more, and a residual structure is in an area ratio of 2% or less, a two-dimensional homogeneous dispersion ratio S defined by S=Sy2/Sx2 (Sx2 is a dispersion value of Mn concentration profile data in a sheet width direction, and Sy2 is a dispersion value of the Mn concentration profile data in a sheet thickness direction) is 0.85 or more and 1.20 or less, and a tensile strength is 1200 MPa or more.
    Type: Grant
    Filed: July 26, 2019
    Date of Patent: November 22, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Mai Nagano, Koutarou Hayashi, Akihiro Uenishi
  • Patent number: 11473178
    Abstract: The present disclosure relates to wear-resistant steel comprising, by weight, carbon (C): 0.19 to 0.28%, silicon (Si): 0.1 to 0.7%, manganese (Mn): 0.6 to 1.6%, phosphorus (P): 0.05% or less, sulfur (S): 0.02% or less, aluminum (Al): 0.07% or less, chromium (Cr): 0.01 to 0.5%, nickel (Ni): 0.01 to 3.0%, copper (Cu): 0.01 to 1.5%, molybdenum (Mo): 0.01 to 0.5%, boron (B): 50 ppm or less, and cobalt (Co): 0.02% or less, further comprising one or more selected from the group consisting of titanium (Ti): 0.02% or less, niobium (Nb): 0.05% or less, vanadium (V): 0.05% or less, and calcium (Ca): 2 to 100 ppm, and comprising a remainder of iron (Fe) and other unavoidable impurities, wherein C, Ni, and Cu satisfy the following relationship 1, wherein a microstructure includes 97 area % or more of martensite: C×Ni×Cu?0.05.??[Relationship 1] .
    Type: Grant
    Filed: December 21, 2018
    Date of Patent: October 18, 2022
    Assignee: POSCO
    Inventors: Seng-Ho Yu, Young-Jin Jung, Yong-Woo Kim
  • Patent number: 11473164
    Abstract: This high-strength cold-rolled steel sheet has a predetermined chemical composition, wherein a microstructure at a ¼ position of a sheet thickness from a surface includes predetermined ranges of volume percentages of tempered martensite, residual austenite, ferrite and bainite, and martensite, wherein a microstructure at a position 25 ?m from the surface includes, predetermined ranges of volume percentage of ferrite and bainite, and martensite and tempered martensite, wherein in the position 25 ?m from the surface, an average grain size of the martensite and the tempered martensite is 5.0 ?m or less, a tensile strength is 1,310 MPa or more, and a uniform elongation is 5.0% or more, and R/t is 5.0 or less, the R/t being a ratio of a limit bend radius R in 90° V-bending to a sheet thickness t.
    Type: Grant
    Filed: March 19, 2019
    Date of Patent: October 18, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takuya Nishio, Kojiro Akiba, Yoshimasa Narita, Kotaro Ohno, Satoshi Kato, Masafumi Azuma
  • Patent number: 11261505
    Abstract: High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness, wherein each soft surface layer has a thickness of more than 10 ?m and 30% or less of the sheet thickness, the soft surface layer has an average Vickers hardness of 0.60 time or less the average Vickers hardness of the sheet thickness ½ position, and the soft surface layer has a nano-hardness standard deviation of 0.8 or less is provided.
    Type: Grant
    Filed: February 20, 2018
    Date of Patent: March 1, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Katsuya Nakano, Yuya Suzuki, Genki Abukawa, Kunio Hayashi
  • Patent number: 11136653
    Abstract: The present invention relates to a steel material for pressure vessels, offshore structures and the like and, more specifically, to a high-strength steel material having excellent low-temperature strain aging impact properties and a method for manufacturing same.
    Type: Grant
    Filed: December 15, 2016
    Date of Patent: October 5, 2021
    Assignee: POSCO
    Inventors: Kyung-Keun Um, Woo-Gyeom Kim
  • Patent number: 11053561
    Abstract: Provided is a steel sheet with excellent abrasion resistance as well as excellent low-temperature toughness and ductility of a base material while having a high strength of a tensile strength of 1,100 MPa or more. The steel sheet is a high-strength steel sheet having a tensile strength of 1,100 MPa or more, wherein the components in the steel satisfy a defined composition, A-value represented by a defined formula (1) is 0.0015 or less, while E-value represented by a defined formula (3) is 0.95 or more, and a Brinell hardness HBW (10/3000) in a position at a depth of 2 mm from a surface of the steel sheet is 360 or more and 440 or less.
    Type: Grant
    Filed: August 26, 2015
    Date of Patent: July 6, 2021
    Assignee: Kobe Steel, Ltd.
    Inventors: Ryota Miyata, Tetsuo Yamaguchi
  • Patent number: 10975450
    Abstract: A low alloy high strength thick-walled seamless steel pipe for oil country tubular goods is provided having a wall thickness of 40 mm or more and a yield strength of 758 MPa or more, the steel pipe including a composition containing, in terms of mass %, C: 0.25 to 0.31%, Si: 0.01 to 0.35%, Mn: 0.55 to 0.70%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.040%, Cu: 0.02 to 0.09%, Cr: 0.8 to 1.5%, Mo: 0.9 to 1.6%, V: 0.04 to 0.10%, Nb: 0.005 to 0.05%, B: 0.0015 to 0.0030%, Ti: 0.005 to 0.020%, and N: 0.005% or less, and having Ti/N of 3.0 to 4.0, with the balance being Fe and inevitable impurities, wherein a cumulative frequency rate at a measurement point at which a Mo segregation degree by a predetermined expression is 1.5 or more is 1% or less.
    Type: Grant
    Filed: November 18, 2016
    Date of Patent: April 13, 2021
    Assignee: JFE Steel Corporation
    Inventors: Mitsuhiro Okatsu, Masao Yuga, Kenichiro Eguchi, Haruo Nakamichi
  • Patent number: 10920298
    Abstract: A steel plate having excellent resistance to fatigue crack growth and manufacturing method thereof, wherein the components of the steel plate in weight percentage are: 0.040-0.070% of C, 0.40-0.70% of Si, 1.30-1.60% of Mn, less than or equal to 0.013% of P, less than or equal to 0.003% of S, less than or equal to 0.30% of Cu, less than or equal to 0.30% of Ni, less than or equal to 0.10% of Mo, 0.008-0.018% of Ti, 0.015-0.030% of Nb, less than or equal to 0.0040% of N, 0.0010-0.0040% of Ca, and the balance being Fe and inevitable impurities. By controlling [% C]×[% Si] between 0.022-0.042, {([% C]+3.33[% Nb])×[% Si]}×Vcooling rate/Tcooling-stopping between 1.15×10?4˜2.2×10?3, carrying out a Ca treatment, and Ca/S=1.0-3.0 and (% Ca)×(% S) 0.28?1.0×10?3, the optimizing the TMCP process, the finished steel plate has a microstructure which a duplex-phase structure of ferrite+uniformly and dispersedly distributed bainite and has an improved resistance to fatigue crack growth.
    Type: Grant
    Filed: November 4, 2015
    Date of Patent: February 16, 2021
    Assignee: Baoshan Iron & Steel Co., Ltd.
    Inventors: Zicheng Liu, Qing Shi
  • Patent number: 10900099
    Abstract: Provided is a steel H-shape for low temperature service including a predetermined chemical composition. A CEV obtained by CEV=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 is 0.40 or less. A sum of an area ratio of one or both of ferrite and bainite at a 1/4 position from an outer side across a thickness of a flange and a 1/6 position from an outer side across a flange width is 90% or more, and an area ratio of a hard phase is 10% or less. An effective grain size is 20.0 ?m or less, and a grain size of the hard phase is 10.0 ?m or less. 30 pieces/mm2 or more Ti oxides having an equivalent circle diameter ranging from 0.01 to 3.0 ?m are included. The thickness of the flange ranges from 12 to 50 mm.
    Type: Grant
    Filed: March 2, 2017
    Date of Patent: January 26, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hidetoshi Ito, Kazutoshi Ichikawa
  • Patent number: 10837089
    Abstract: A thick steel plate for high heat input welding and having great heat-affected area toughness and a manufacturing method therefor, comprising the steps of smelting, casting, rolling, and cooling. Also, the chemical composition of the steel plate satisfies 1?Ti/N?6 and (Ca+REM+Zr)/Al?0.11, where the effective S content in steel=S-0.8Ca-0.34REM-0.35Zr. and the effective S content in steel: 0.0006-0.005%; finely dispersed inclusions may be formed, and the amount of composite inclusion CaO+Al2O3+MnS+TiN in the steel plate is at a proportion of ?12%. With respect to welding in which the thickness of the steel plate is 50-70 mm, the tensile strength of a base material is ?510 MPa. and welding input energy is 200-400 kJ/cm, the average Charpy impact work of a welding heat-affected area of the steel plate at ?40° C. is 100 J or more, and at the same time, the average Charpy aging impact work of the base material of ½ thickness at ?40° C. is 46 J or more.
    Type: Grant
    Filed: December 8, 2016
    Date of Patent: November 17, 2020
    Assignee: Baoshan Iron & Steel Co., Ltd.
    Inventors: Jian Yang, Shan Gao, Zhigang Ma, Ruizhi Wang, Caiyi Zhang, Junkai Wang, Guodong Xu, Yunan Wang
  • Patent number: 10829840
    Abstract: A steel sheet for hot pressing includes in a chemical composition, in percent by mass, C of 0.1% to 0.4%, Si of greater than 0% to 2.0%, Mn of 0.5% to 3.0%, P of greater than 0% to 0.015%, S of greater than 0% to 0.01%, B of 0.0003% to 0.01%, N of greater than 0% to 0.05%, Al in a content of 2×[N]% to 0.3% at a Si content of greater than 0.5% to 2.0%; or Al in a content of (0.20+2×[N]?0.40×[Si]N)% to 0.3% at a Si content of 0% to 0.5%, where [N] and [Si] are contents of N and Si, respectively, in mass percent, with the remainder being iron and inevitable impurities, where contents of Ti, Zr, Hf, and Ta, of the inevitable impurities, are each controlled to 0.005% or lower. The steel sheet includes nitride-based inclusions with an equivalent circle diameter of 1 ?m or more in a number density of 0.10 per square millimeter.
    Type: Grant
    Filed: December 10, 2015
    Date of Patent: November 10, 2020
    Assignees: voestalpine Stahl GmbH, Kobe Steel, Ltd.
    Inventors: Toshio Murakami, Junya Naitou, Keisuke Okita, Shushi Ikeda, Shinji Sato, Andreas Pichler, Thomas Kurz
  • Patent number: 10724125
    Abstract: Spring steel includes: as a chemical composition, by mass %, C: 0.40% to 0.60%, Si: 0.90% to 2.50%, Mn: 0.20% to 1.20%, Cr: 0.15% to 2.00%, Ni: 0.10% to 1.00%, Ti: 0.030% to 0.100%, B: 0.0010% to 0.0060%, N: 0.0010% to 0.0070%, Cu: 0% to 0.50%, Mo: 0% to 1.00%, V: 0% to 0.50%, Nb: 0% to 0.10%, P: limited to less than 0.020%, S: limited to less than 0.020%, Al: limited to less than 0.050%, and a remainder including Fe and impurities, in a case where [Ti] represents a Ti content and [N] represents a N content by mass %, the chemical composition satisfies ([Ti]?3.43×[N])>0.03, and a total number density of a Ti carbide and a Ti carbonitride having a diameter of 5 nm to 100 nm is more than 50 piece/?m3.
    Type: Grant
    Filed: May 13, 2016
    Date of Patent: July 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takahisa Suzuki, Manabu Kubota, Shuji Kozawa, Hirotsugu Miyamoto
  • Patent number: 10724114
    Abstract: A high-strength cold-rolled steel sheet is provided that has a chemical composition that consists of, by mass %, C: 0.050 to 0.40%, Si: 0.01 to 3.0%, Mn: 1.0 to 5.0%, sol. Al: 0.001 to 1.0%, Ti: 0.005 to 0.20%, B: 0.0005 to 0.010%, P: 0.1% or less, S: 0.01% or less, O: 0.1% or less, N: 0.01% or less, Cr: 0 to 1.0%, Mo: 0 to 1.0%, Ni: 0 to 1.0%, Cu: 0 to 1.0%, Sn: 0 to 0.50%, Nb: 0 to 0.20%, V: 0 to 0.50%, W: 0 to 0.50%, Ca: 0 to 0.01%, Mg: 0 to 0.01%, Bi: 0 to 0.01%, Sb: 0 to 0.10%, Zr: 0 to 0.01%, and REM: 0 to 0.01%, with the balance being Fe and impurities, and that satisfies the formulas [sol. Bs/B?0.50] and [sol. Bq/B>0.50] (where, B: B amount in the steel; sol. Bs: soluble B amount in a surface layer portion of the steel; and sol. Bq: soluble B amount in the steel interior).
    Type: Grant
    Filed: June 29, 2016
    Date of Patent: July 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takafumi Yokoyama, Hiroyuki Kawata, Riki Okamoto
  • Patent number: 10718040
    Abstract: The present invention provides a hot-rolled steel sheet capable of preventing softening of the strength of a sheet-thickness central portion of the steel sheet in thermal treatment, even in the case where an amount of working performed on the steel sheet is small and a work hardening rate is low. A hot-rolled steel sheet of the present invention consists of chemical components of, in mass %, C: 0.040 to 0.150%, Si: 0 to 0.500%, Mn: 0.10 to 1.50%, P: 0 to 0.050%, S: 0 to 0.020%, Al: 0.010 to 0.050%, N: 0.0010 to 0.0060%, Nb: 0.008 to 0.035%, Cu: 0 to 0.10%, Ni: 0 to 0.10%, Cr: 0 to 0.02%, Mo: 0 to 0.020%, V: 0 to 0.020%, Ca: 0 to 0.0100%, B: 0 to 0.0050%, and the balance: Fe and impurities. The hot-rolled steel sheet contains 0.005 to 0.030% dissolved Nb. An area fraction of ferrite structure is 85% or more, the balance is cementite and/or pearlite structure, and an average crystal grain size of ferrite is equal to or more than 5 ?m and equal to or less than 20 ?m.
    Type: Grant
    Filed: April 21, 2016
    Date of Patent: July 21, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Teruki Hayashida, Kazuya Ootsuka, Akifumi Sakakibara
  • Patent number: 10702955
    Abstract: The purpose of the present invention is to provide a flux cored wire which has good high-temperature cracking resistance, and which enables the achievement of a welded part exhibiting excellent coating adhesion. The present invention relates to a metal flux cored wire for gas-shielded are welding, which contains, relative to the total mass of the wire, 0.02-0.30% by mass of C, 0.3-1.5% by mass of Si, 0.3-2.5% by mass of Mn, and oxide of at least one element selected from the group consisting of Si, Cr and Ni in an amount of 0.01-0.30% by mass in total, 0.020% by mass or less of S, and 0.3% by mass or less of Al, Ca, Mg, K and Na in total in the form of metals or alloys, with the balance made up of Fe and unavoidable impurities.
    Type: Grant
    Filed: April 22, 2016
    Date of Patent: July 7, 2020
    Assignee: Kobe Steel, Ltd.
    Inventors: Minoru Miyata, Reiichi Suzuki, Kei Yamazaki
  • Patent number: 10689721
    Abstract: The present invention provides a case hardening steel which satisfies the following expression (1) representing a relationship between a maximum deformation resistance ?MAX (MPa) and a DI value, the maximum deformation resistance ?MAX (MPa) being obtained when a test piece which has a size of ? 15×22.5 mm and is cut out from a material after spheroidizing, is subjected to compressive deformation by cold forging at a compression ratio of 70% in a state that an end surface thereof is restrained, and the DI value being obtained from a Jominy quenching test: ?MAX<12.8×DI+745 . . . Expression (1). Additionally, the present invention obtains a carburized part by subjecting the case hardening steel to carburizing and quenching.
    Type: Grant
    Filed: January 23, 2015
    Date of Patent: June 23, 2020
    Assignee: DAIDO STEEL CO., LTD.
    Inventors: Kyohei Nakayama, Toshiyuki Morita, Keisuke Inoue
  • Patent number: 10550962
    Abstract: The steel material according to this invention contains, in mass %, C: 0.15 to 0.45%, Si: 0.10 to 1.0%, Mn: 0.10 to less than 0.90%, P: 0.05% or less, S: 0.01% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Cr: 0.1 to 2.5%, Mo: 0.35 to 3.0%, and Co: 0.50 to 3.0%, and satisfies expressions (1) and (2), and contains 90% or more of tempered martensite by volume ratio: C+Mn/6+(Cr+Mo+V)/5+(Cu+Ni)/15?Co/6+??0.50??(1 ) (3C+Mo+3Co)/(3Mn+Cr)?1.0??(2 ) Effective B=B?11(N?Ti/3.4)/14??(3 ) where, ? in expression (1) is 0.250 when effective B (mass %) defined by expression (3) is 0.0003% or more, and is 0 when the effective B is less than 0.0003.
    Type: Grant
    Filed: February 20, 2017
    Date of Patent: February 4, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Yuji Arai
  • Patent number: 10443114
    Abstract: A steel material for oil country tubular goods that has a high strength and excellent SSC resistance is provided. The steel material according to this invention contains, in mass %, C: more than 0.45 to 0.65%, Si: 0.10 to 1.0%, Mn: 0.1 to 1.0%, P: 0.050% or less, S: 0.010% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Cr: 0.1 to 2.5%, Mo: 0.25 to 5.0%, and Co: 0.05 to 5.0%, and satisfies expressions (1) and (2), and contains 90% or more of tempered martensite by volume ratio: C+Mn/6+(Cr+Mo+V)/5+(Cu+Ni)/15?Co/6+??0.70??(1) (3C+Mo+3Co)/(3Mn+Cr)?1.0??(2) Effective B=B?11(N?Ti/3.4)/14??(3) where, ? in expression (1) is 0.250 when effective B (mass %) defined by expression (3) is 0.0003% or more, and is 0 when effective B is less than 0.0003%.
    Type: Grant
    Filed: February 20, 2017
    Date of Patent: October 15, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Yuji Arai
  • Patent number: 10391742
    Abstract: A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and an AlN precipitation parameter.
    Type: Grant
    Filed: June 14, 2017
    Date of Patent: August 27, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Manabu Kubota
  • Patent number: 10392707
    Abstract: A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and a TiC precipitation parameter.
    Type: Grant
    Filed: June 16, 2017
    Date of Patent: August 27, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Manabu Kubota
  • Patent number: 10301703
    Abstract: Disclosed is a high-strength welded steel pipe for airbag inflators that has high toughness and workability. A base material portion of the steel pipe has a composition containing, in mass %, C: 0.02 to 0.08%, Si: 0.001 to 1.0%, Mn: 0.1 to 2.0%, P: 0.1% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Ti: 0.01 to 0.20%, and V: 0.01 to 0.50%, with the balance being Fe and incidental impurities. The base material portion has a structure that includes a ferrite phase having an average grain size of 10 ?m or less at an area fraction of 90% or more and a Ti, V-based carbide having an average grain size of 10 nm or less and dispersed in the ferrite phase. The welded steel pipe has a high tensile strength TS of 780 MPa or more and a strength-elongation balance TS×El of 15,000 MPa % or more. The difference ?HV in Vickers hardness between the base material portion and the welded portion is 60 points or less.
    Type: Grant
    Filed: October 19, 2015
    Date of Patent: May 28, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Masatoshi Aratani, Yoshikazu Kawabata, Kenichi Iwazaki, Ryoji Matsui
  • Patent number: 10227682
    Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.
    Type: Grant
    Filed: February 6, 2015
    Date of Patent: March 12, 2019
    Assignee: THE JAPAN STEEL WORKS, LTD.
    Inventors: Kouichi Takasawa, Yoru Wada, Ryoji Ishigaki, Yasuhiko Tanaka
  • Patent number: 9994940
    Abstract: This high carbon steel wire rod, which has excellent drawability in addition to high strength required for a wire rod, contains 0.6-1.5% of C, 0.1-1.5% of Si, 0.1-1.5% of Mn, 0.02% or less of P (excluding 0%), 0.02% or less of S (excluding 0%), 0.03-0.12% of Ti, 0.001-0.01% of B and 0.001-0.005% of N, with solid-solved B being 0.0002% or more, solid-solved N being 0.0010% or less, and the balance being made up of iron and inevitable impurities. In addition, the content of Ti solid-solved in the steel is 0.002% by mass or more, and the content of Ti that formed carbides is 0.020% by mass or more.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: June 12, 2018
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroshi Oura, Nao Yoshihara
  • Patent number: 9988697
    Abstract: This high-strength hot-rolled steel sheet having excellent local deformability contains, in mass %, C: 0.07% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 10 ?m or less.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: June 5, 2018
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 9970088
    Abstract: A multi-phase steel including in % wt. C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 0.2-0.7%, Al: 0.5-1.5%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally at least one of Ti, B, and V according to the following stipulation: Ti: up to 0.1%, B: up to 0.002%, V: up to 0.15%, with the remainder iron and unavoidable impurities, wherein the microstructure has at least 10% vol. ferrite and at least 6% vol. residual austenite and the steel has a tensile strength Rm of at least 950 MPa, a yield point ReL of at least 500 MPa and an elongation at break A80 measured in the transverse direction of at least 15%. A method of producing the multi-phase steel.
    Type: Grant
    Filed: September 22, 2011
    Date of Patent: May 15, 2018
    Assignee: ThyssenKrupp Steel Europe AG
    Inventors: Ekaterina Bocharova, Dorothea Mattissen, Roland Sebald, Daniel Krizan, Andreas Pichler
  • Patent number: 9914988
    Abstract: Provided are a high-strength cold-rolled steel sheet having excellent formability, excellent ductility, excellent hole expansibility, and high yield ratio and a method for producing the same. The high-strength cold-rolled steel sheet contains 0.05% to 0.15% C, 0.10% to 0.90% Si, 1.0% to 2.0% Mn, 0.005% to 0.05% P, 0.0050% or less S, 0.01% to 0.10% Al, 0.0050% or less N, and 0.010% to 0.100% Nb, which are chemical components, on a mass basis, the balance being Fe and unavoidable impurities; has a microstructure which is a multi-phase structure containing 90% or more of a ferrite phase and 0.5% to less than 5.0% of a martensite phase on a volume fraction basis, the remainder being low-temperature transformation phases; and has a yield ratio of 70% or more.
    Type: Grant
    Filed: November 30, 2011
    Date of Patent: March 13, 2018
    Assignee: JFE Steel Corporation
    Inventors: Katsutoshi Takashima, Yuki Toji, Kohei Hasegawa
  • Patent number: 9896736
    Abstract: The present invention provides a method for manufacturing a hot stamped body having a vertical wall, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac1° C. and lower than Ac3° C.; a cooling step of cooling the heated cold-rolled steel sheet from the highest heating temperature to 660° C. at a cooling rate of equal to or less than 10° C./s; and a holding step of holding the cooled cold-rolled steel sheet in a temperature range of 550° C. to 660° C. for one minute to 10 minutes.
    Type: Grant
    Filed: October 28, 2016
    Date of Patent: February 20, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshimasa Tomokiyo, Kunio Hayashi, Toshimitsu Aso
  • Patent number: 9883588
    Abstract: According to this invention, an oriented copper plate which has a highly developed cube texture and has strength and breaking elongation greater than those of a conventional material having a cube texture, a copper-clad laminate, a flexible circuit board that is excellent in terms of folding flexibility, and an electronic device are provided, and a process for producing the oriented copper plate is established. This invention relates: an oriented copper plate, which contains 0.03% by mass to 1.0% by mass of Cr, the remainder of which is composed of copper and inevitable impurities, wherein the copper plate has a <100> main orientation so that the area percentage of a <100> preferred orientation region is not less than 60.
    Type: Grant
    Filed: December 11, 2015
    Date of Patent: January 30, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Keiichi Kimura, Tomohiro Uno, Kazuaki Kaneko
  • Patent number: 9840751
    Abstract: Provided is a method for manufacturing a hot stamped body, the method including: a hot-rolling step; a coiling step; a cold-rolling step; a continuous annealing step; and a hot stamping step, in which the continuous annealing step includes a heating step of heating the cold-rolled steel sheet to a temperature range of equal to or higher than Ac1° C. and lower than Ac3° C.; a cooling step of cooling the heated cold-rolled steel sheet from the highest heating temperature to 660° C. at a cooling rate of equal to or less than 10° C./s; and a holding step of holding the cooled cold-rolled steel sheet in a temperature range of 550° C. to 660° C. for one minute to 10 minutes.
    Type: Grant
    Filed: February 2, 2017
    Date of Patent: December 12, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kunio Hayashi, Toshimitsu Aso, Toshimasa Tomokiyo, Hitoshi Tanino, Ryozo Wada
  • Patent number: 9797033
    Abstract: The invention provides a wear-resistant steel plate, which has the following chemical composition (wt. %): C: 0.08-0.21%, Si: 0.15-0.45%, Mn: 1.10-1.80%, P: ?0.015%, S: ?0.010%, Nb: 0.010-0.040%, Al: 0.010-0.080%, B: 0.0006-0.0014%, Ti: 0.005-0.050%, Ca: 0.0010-0.0080%, V?0.080%, Cr?0.60%, N?0.0080%, O?0.0060%, H?0.0004%, wherein 0.025%?Nb+Ti?0.080%, 0.030%?Al+Ti?0.12%, and the balance being Fe and unavoidable impurities. The invention also provides a method of manufacturing the wear-resistant steel plate, comprising smelting, casting, rolling, post-rolling direct cooling, inter alia. The wear-resistant steel plate obtained from the above composition and process has perfect weldability, high strength, high hardness, good low-temperature toughness, and excellent machinability, and is suitable for quick-wear devices in engineering and mining machinery, such as bucket, mining vehicle body and scraper transporter, etc.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: October 24, 2017
    Assignee: BAOSHAN IRON & STEELE CO., LTD.
    Inventors: Hongbin Li, Liandeng Yao, Yuchuan Miao
  • Patent number: 9791032
    Abstract: Systems and methods in accordance with embodiments of the invention implement bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a method of fabricating a strain wave gear includes: shaping a BMG-based material using a mold in conjunction with one of a thermoplastic forming technique and a casting technique; where the BMG-based material is shaped into one of: a wave generator plug, an inner race, an outer race, a rolling element, a flexspline, a flexspline without a set of gear teeth, a circular spline, a circular spline without a set of gear teeth, a set of gear teeth to be incorporated within a flexspline, and a set of gear teeth to be incorporated within a circular spline.
    Type: Grant
    Filed: March 7, 2016
    Date of Patent: October 17, 2017
    Assignee: California Institute of Technology
    Inventors: Douglas C. Hofmann, Brian H. Wilcox
  • Patent number: 9790578
    Abstract: A steel for a tracked undercarriage component is used as a material constituting a track link (9), for example, and contains: not less than 0.39% by mass and not more than 0.45% by mass of carbon, not less than 0.2% by mass and not more than 1.0% by mass of silicon, not less than 0.10% by mass and not more than 0.90% by mass of manganese, not less than 0.002% by mass and not more than 0.005% by mass of sulfur, not less than 0.1% by mass and not more than 3.0% by mass of nickel, not less than 0.70% by mass and not more than 1.50% by mass of chromium, and not less than 0.10% by mass and not more than 0.60% by mass of molybdenum, with the balance made of iron and unavoidable impurities.
    Type: Grant
    Filed: May 8, 2014
    Date of Patent: October 17, 2017
    Assignee: KOMATSU LTD.
    Inventors: Eiji Amada, Kazuo Maeda, Takeji Kajiura
  • Patent number: 9702031
    Abstract: The present invention provides a bake-hardenable high-strength cold-rolled steel sheet having excellent bake hardenability, cold aging resistance, and deep-drawability, and reduced planar anisotropy, containing chemical components in % by mass of: C: 0.0010% to 0.0040%, Si: 0.005% to 0.05%, Mn: 0.1% to 0.8%, P: 0.01% to 0.07%, S: 0.001% to 0.01%, Al: 0.01% to 0.08%, N: 0.0010% to 0.0050%, Nb: 0.002% to 0.020%, and Mo: 0.005% to 0.050%, a value of [Mn %]/[P %] being in the range of 1.6 to 45, where [Mn %] is an amount of Mn and [P %] is an amount of P, an amount of C in solid solution obtained from [C %]?(12/93)×[Nb %] being in the range of 0.0005% to 0.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: July 11, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Satoshi Akamatsu, Masaharu Oka
  • Patent number: 9695493
    Abstract: A dual phase or complex phase steel strip showing no tigerstripes. The steel strip having an ultimate tensile strength Rm classifying for 1000 MPa steel category, includes (in mass percent) C 0.09-0.19%; Mn 1.9-2.6%; Si at most 0.1%; Cr 0.4-0.8%; Mo at most 0.3%; Ni at most 0.4%; Al 0.02-1.3%; and optionally one or more of the following elements: Nb at most 0.08%; P equal to or more than 0.0005%; N equal to or less than 0.015%; Ti equal to or less than 0.1%; V equal to or less than 0.1%; B equal to or less than 0.01%; wherein the sum of Cr, Mo and Ni is at least 0.5%; the balance being Fe and inevitable impurities.
    Type: Grant
    Filed: April 5, 2013
    Date of Patent: July 4, 2017
    Assignee: TATA STEEL IJMUIDEN BV
    Inventors: Egbert Jansen, Edward Anton Frederik Span, Richard Mostert, Theo Arnold Kop
  • Patent number: 9593400
    Abstract: A dual phase or complex phase steel strip showing no tigerstripes. The steel strip includes, in mass percent, the following elements: C 0.08-0.11%; Mn 1.70-2.20%; Si at most 0.1%; Cr 0.40-0.70%; Mo at most 0.3%; Ni at most 1.0%, Al 0.01-1.50%; Nb at most 0.07%; P equal to or more than 0.005%; N equal to or less than 0.015%; Ti equal to or less than 0.1%; V equal to or less than 0.1%; B equal to or less than 0.01%; wherein the sum of Cr, Mo and Ni is at least 0.5%; the balance being Fe and inevitable impurities.
    Type: Grant
    Filed: April 5, 2013
    Date of Patent: March 14, 2017
    Assignee: TATA STEEL IJMUIDEN BV
    Inventors: Egbert Jansen, Edward Anton Frederik Span, Richard Mostert, Theo Arnold Kop
  • Patent number: 9592772
    Abstract: [Problem] To provide a steel sheet hot-dip-plated with a Zn—Al—Mg-based alloy coating, which is remarkably improved in point of all the burring workability, the liquid metal embrittlement cracking resistance and the corrosion resistance in the welded part thereof, as a steel material favorable for arc-welded structural members.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: March 14, 2017
    Assignee: NISSHIN STEEL CO., LTD.
    Inventors: Kentaro Hirata, Yukio Katagiri, Susumu Fujiwara, Kazuaki Hosomi, Masaaki Uranaka
  • Patent number: 9499408
    Abstract: The invention relates to graphene sheets and to a method for making the same in which a solution of graphene or graphite oxide is applied to a blue steel substrate and dried.
    Type: Grant
    Filed: September 4, 2013
    Date of Patent: November 22, 2016
    Assignee: TRUE 2 MATERIALS PTE LTD
    Inventor: William Rieken
  • Patent number: 9394594
    Abstract: A steel contains, by weight: C: 0.3% to 0.5%, Si: 0.1% to 0.5%, Mn: 0.1% to 1%, P: 0.03% or less, S: 0.005% or less, Cr: 0.3% to 1.5%, Mo: 1.0% to 1.5%, Al: 0.01% to 0.1%, V: 0.03% to 0.06%, Nb: 0.04% to 0.15%, Ti: 0 to 0.015%, N: 0.01% or less, the remainder of the chemical composition of the steel being constituted by Fe and impurities or residuals resulting from or necessary to steel production and casting processes. The steel enables to produce seamless tubes with a yield strength after heat treatment of 862 MPa or more which are particularly SSC-resistant.
    Type: Grant
    Filed: February 12, 2010
    Date of Patent: July 19, 2016
    Assignee: VALLOUREC OIL AND GAS FRANCE
    Inventors: Christoph Bosch, Axel Kulgemeyer, Jean Leyer, Michel Piette
  • Patent number: 9212410
    Abstract: The present invention inexpensively provides with high productivity and good yield a steel rod superior in drawability and a steel wire superior in twistability using the same as a material, that is, draws a high strength steel rod superior in ductility where the chemical components contain C: 0.80 to 1.20%, Si: 0.1 to 1.5%, Mn: 0.1 to 1.0%, Al: 0.01% or less, Ti: 0.01% or less, one or both of W: 0.005 to 0.2% and Mo: 0.003 to 0.2%, N: 10 to 30 ppm, B: 4 to 30 ppm (of which, solute B is 3 ppm or more), and O: 10 to 40 ppm, which has a balance of Fe and unavoidable impurities, has an area percentage of pearlite structures of 97% or more, has a balance of non-pearlite structures, and has a total of the area percentage of the non-pearlite structures and the area percentage of the coarse pearlite structures of 15% or less, to obtain high strength steel wire superior in ductility having a tensile strength of 3600 MPa or more and a number density of voids of lengths of 5 ?m or more at the center of 100/mm2 or less.
    Type: Grant
    Filed: March 9, 2009
    Date of Patent: December 15, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shingo Yamasaki, Seiki Nishida
  • Patent number: 9039962
    Abstract: A steel for an induction hardening including, by mass %, C: more than 0.75% to 1.20%, Si: 0.002 to 3.00%, Mn: 0.20 to 2.00%, S: 0.002 to 0.100%, Al: more than 0.050% to 3.00%, P: limited to 0.050% or less, N: limited to 0.0200% or less, O: limited to: 0.0030% or less, and the balance composing of iron and unavoidable impurities, wherein an Al content and a N content satisfy, by mass %, Al?(27/14)×N>0.050%.
    Type: Grant
    Filed: February 15, 2011
    Date of Patent: May 26, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Manabu Kubota, Toshiharu Aiso, Kei Miyanishi