Zinc(zn), Zinc Base Alloy Or Unspecified Galvanizing Patents (Class 148/533)
  • Patent number: 10774405
    Abstract: Steel has a chemical composition that contains 0.050% to 0.40% of C, 0.50% to 3.0% of Si, 3.0% to 8.0% of Mn, and 0.001% to 3.0% of sol. Al, by mass %, and has a metallographic structure that contains 10% to 40% of austenite in terms of % by volume. The average concentration of C in austenite is 0.30% by 0.60%, by mass %, structure uniformity, which is represented by a value obtained by subtracting the minimum value from the maximum value of Vickers hardness that is measured, in the metallographic structure is 30 Hv or less, and the tensile strength is 900 MPa to 1800 MPa.
    Type: Grant
    Filed: January 6, 2014
    Date of Patent: September 15, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Koutarou Hayashi, Akira Seki, Kazuya Mishio, Shuhei Shimokawa
  • Patent number: 10731241
    Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si phase particles that are ?2 ?m and have a globular shape. A method of forming an Al—Zn—Si—Mg alloy coated strip comprises (a) heat treating a solidified coating to facilitate globularisation of Mg2Si phase particles in the coating and/or (b) changing the coating bath chemistry to form intermetallic compound phases that act as nucleation sites for Mg2Si phase particles with the result that small Mg2Si particles form on solidification of the coating.
    Type: Grant
    Filed: May 27, 2010
    Date of Patent: August 4, 2020
    Assignee: Bluescope Steel Limited
    Inventors: Ross McDowall Smith, Qiyang Liu, Joe Williams
  • Patent number: 10718044
    Abstract: A hot-dip galvanized steel sheet includes: a predetermined chemical composition; and a steel structure represented by: in terms of area ratio, polygonal ferrite: 10% or less; upper bainite: 20% or less; retained austenite: 5% or less; and martensite: 70% or more, in which: martensite having Fe carbides at a number density of 1×106/mm2 or more is contained by 50% or more, in terms of area ratio, with respect to the entire amount of martensite; and the steel structure has an average effective crystal grain diameter of 5.0 ?m or less.
    Type: Grant
    Filed: July 15, 2016
    Date of Patent: July 21, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takafumi Yokoyama, Kunio Hayashi, Masafumi Azuma, Eisaku Sakurada, Hiroyuki Kawata, Genki Abukawa
  • Patent number: 10711336
    Abstract: Provided is an alloyed hot-dip galvanized steel sheet including a base steel sheet, the base steel sheet containing a given amount of C, Si, Mn, and other elements. The alloyed hot-dip galvanized steel sheet is provided with an alloyed hot-dip galvanized layer on a surface of the base steel sheet, the alloyed hot-dip galvanized layer containing, in mass %, Fe: more than or equal to 5% and less than or equal to 15%, and having a thickness of more than or equal to 3 ?m and less than or equal to 30 ?m.
    Type: Grant
    Filed: November 8, 2018
    Date of Patent: July 14, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Soshi Fujita, Shintaro Yamanaka
  • Patent number: 10604829
    Abstract: Disclosed herein is a high-strength plated steel sheet having a plated layer on the surface of a base steel sheet and containing predetermined steel components. The steel sheet includes, in the order from the interface of the base steel sheet and the plated layer towards the base steel sheet: a soft layer having a Vickers hardness that is 90% or less of the Vickers hardness at a portion t/4 of the base steel sheet, where t is a sheet thickness of the base steel sheet; and a hard layer consisting of a structure which is mainly composed of martensite and bainite and in which the average grain size of prior austenite is 20 ?m or less. The average depth D of the soft layer is 20 ?m or greater, and the average depth d of an internal oxide layer is 4 ?m or greater and smaller than D.
    Type: Grant
    Filed: January 5, 2016
    Date of Patent: March 31, 2020
    Assignee: Kobe Steel, Ltd.
    Inventors: Muneaki Ikeda, Michiharu Nakaya
  • Patent number: 10590521
    Abstract: Steel strip provided with a hot dip galvanized zinc alloy coating layer, in which the coating of the steel strip is carried out in a bath of molten zinc alloy, the zinc alloy in the coating of: 0.3-2.3 weight % magnesium; 0.6-2.3 weight % aluminium; optional <0.2 weight % of one or more additional elements; unavoidable impurities; the remainder being zinc in which the zinc alloy coating layer has a thickness of 3-12 ?m.
    Type: Grant
    Filed: May 3, 2017
    Date of Patent: March 17, 2020
    Assignee: TATA STEEL IJMUIDEN B.V.
    Inventors: Theodorus Franciscus Jozef Maalman, Robert Bleeker, Margot Julia Vlot
  • Patent number: 10584407
    Abstract: Zn alloy plated steel material having excellent weldability and processed-part corrosion resistance and a method for production of Zn alloy plated steel material are provided. In the Zn alloy plated steel material comprising base steel material and a Zn alloy plating layer, the Zn alloy plating layer includes, by wt %, Al: 0.1-5.0%, Mg: 0.1-5.0%, as well as a remainder of Zn and inevitable impurities. The Zn alloy plated steel material includes a lower interface layer and an upper interface layer between the base steel material and the Zn alloy plating layer, wherein the lower interface layer is formed on the base steel material and has a dense structure, and the upper interface layer is formed on the lower interface layer and has a network-type or island-type structure.
    Type: Grant
    Filed: December 24, 2015
    Date of Patent: March 10, 2020
    Assignee: POSCO
    Inventors: Min-Suk Oh, Sang-Heon Kim, Tae-Chul Kim, Jong-Sang Kim, Hyun-Chu Yun, Bong-Hwan Yoo, Il-Ryoung Sohn
  • Patent number: 10570473
    Abstract: Provided is a high-strength cold-rolled steel sheet having excellent ductility and stretch-flangeability as well as weldability in a range in which a tensile strength is 980 MPa or higher and a 0.2% yield strength is less than 700 MPa (preferably 500 MPa or higher). In the high-strength cold-rolled steel sheet of the present invention, the chemical composition is adjusted as appropriate, and the area ratio of below-mentioned metal structures at a position of ¼ sheet thickness in the steel sheet satisfies following requirements: tempered martensite: 10 area % to less than 30 area %, bainite: more than 70 area %, total of tempered martensite and bainite: 90 area % or more, ferrite: 0 area % to 5 area %, and retained austenite: 0 area % to 4 area %. The high-strength cold-rolled steel sheet has excellent ductility, stretch-flangeability, and weldability, and has a tensile strength of 980 MPa or higher and a 0.2% yield strength of less than 700 MPa.
    Type: Grant
    Filed: March 19, 2015
    Date of Patent: February 25, 2020
    Assignee: Kobe Steel, Ltd.
    Inventors: Michitaka Tsunezawa, Michiharu Nakaya
  • Patent number: 10563280
    Abstract: The present invention relates to a high-strength and high-manganese steel sheet suitable for an outer panel or a vehicle body of a transport vehicle and, more specifically, to a high-strength and high-manganese steel sheet having excellent vibration-proof properties and a method for producing the same.
    Type: Grant
    Filed: December 24, 2013
    Date of Patent: February 18, 2020
    Assignee: POSCO
    Inventors: Sung-Kyu Kim, Kwang-Geun Chin, Tae-Jin Song, Tai-Ho Kim, Won-Tae Cho, Sun-Ho Jeon
  • Patent number: 10550457
    Abstract: Zn alloy plated steel material having excellent weldability and processed-part corrosion resistance and a method for production of Zn alloy plated steel material are provided. In the Zn alloy plated steel material comprising base steel material and a Zn alloy plating layer, the Zn alloy plating layer includes, by wt %, Al: 0.1-5.0%, Mg: 0.1-5.0%, as well as a remainder of Zn and inevitable impurities. The Zn alloy plated steel material includes a lower interface layer and an upper interface layer between the base steel material and the Zn alloy plating layer, wherein the lower interface layer is formed on the base steel material and has a dense structure, and the upper interface layer is formed on the lower interface layer and has a network-type or island-type structure.
    Type: Grant
    Filed: December 24, 2015
    Date of Patent: February 4, 2020
    Assignee: POSCO
    Inventors: Min-Suk Oh, Sang-Heon Kim, Tae-Chul Kim, Jong-Sang Kim, Hyun-Chu Yun, Bong-Hwan Yoo, Il-Ryoung Sohn
  • Patent number: 10544477
    Abstract: A method for manufacturing a high-strength galvanized steel sheet includes performing hot rolling, cold rolling, first annealing, pickling, and second annealing. The first annealing is performed to obtain a steel sheet having a steel microstructure including ferrite in an amount of 10% or more and 60% or less in terms of area ratio, and martensite, bainite, and retained austenite in a total amount of 40% or more and 90% or less in terms of area ratio. The second annealing includes heating to an annealing temperature of 750° C. or higher and 850° C. or lower, holding at the annealing temperature for 10 seconds or more and 500 seconds or less, cooling at an average cooling rate of 1° C./s or more and 15° C./s or less, performing a galvanizing treatment, and cooling to a temperature of 150° C. or lower at an average cooling rate of 5° C./s or more and 100° C./s or less.
    Type: Grant
    Filed: June 9, 2015
    Date of Patent: January 28, 2020
    Assignee: JFE Steel Corporation
    Inventors: Hideyuki Kimura, Koichiro Fujita, Hiroshi Hasegawa, Mai Aoyama
  • Patent number: 10538830
    Abstract: A steel sheet of the present invention has a steel structure obtained by performing a soaking at a dual phase region temperature of Ac1 temperature or higher and lower than Ac3 temperature for a soaking time of 15 seconds or longer and 35 seconds or shorter, next, performing a primary cooling to a temperature range of 250° C. or higher and 380° C. or lower within 3 seconds at a cooling rate of 0.5° C./s or more and 30° C./s or less, and performing a retention in a temperature range of 260° C. or higher and 370° C. or lower for 180 seconds or longer and 540 seconds or shorter, in which a yield ratio is 65% or less and tensile strength is 590 MPa or more after the primary cooling.
    Type: Grant
    Filed: October 5, 2012
    Date of Patent: January 21, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuji Fukumoto, Takashi Aramaki, Junichi Yasui, Norimitsu Harada
  • Patent number: 10526671
    Abstract: A high-strength cold-rolled steel sheet having excellent ductility and stretch flangeability includes: a chemical composition consisting, in mass %, C: 0.06 to 0.3, Si: 0.6 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, total of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003% and the remainder of Fe and impurities; a microstructure having a main phase including at least 40 area % in total of martensite and/or bainite; and a texture in which proportion of an average X-ray intensity in an {100}<011> to {211}<011> orientations relative to an average X-ray intensity of a random structure not having a texture is less than 6.
    Type: Grant
    Filed: February 13, 2013
    Date of Patent: January 7, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
  • Patent number: 10472692
    Abstract: A method for manufacturing a high-strength sheet having improved formability and ductility accord which the chemical composition of the steel contains, in percent by weight: 0.25%<C?0.4% 2.3%?Mn?3.5% 2.3%?Si?3% Al?0.040% the remainder being Fe and unavoidable impurities, the method comprising the steps of annealing a rolled sheet made of said steel by soaking it at an annealing temperature AT higher than the Ac3 transformation point of the steel, quenching the sheet by cooling it down to a quenching temperature QT between Ms?65° C. and Ms?115° C., being in order to obtain a final structure containing at least 65% of martensite and at least 5% of residual austenite, the sum of the ferrite and bainite contents being less than 10%, Ms being the Ms transformation point of the steel according to the Andrews formula, heating the sheet up to an overaging temperature PT between 360° C. and 500° C.
    Type: Grant
    Filed: July 3, 2015
    Date of Patent: November 12, 2019
    Assignee: ArcelorMittal
    Inventors: Gunhild Föjer, Michel Soler, Jean-Christophe Hell
  • Patent number: 10465272
    Abstract: Provided is a high-strength hot-dip galvanized steel sheet having excellent plating adhesion, formability, and hole expandability with an ultimate tensile strength of 980 MPa or more, the hot-dip galvanized steel sheet comprising a hot-dip galvanized layer formed on a surface of a base steel sheet. The base steel sheet contains, by mass %, C: 0.05% to 0.4%; Si: 0.01% to 3.0%; Mn: 0.1% to 3.0%; Al: 0.01 to 2.0%; in which Si+Al>0.5%, P: limited to 0.04% or less; S: limited to 0.05% or less; N: limited to 0.01% or less; and a balance including Fe and inevitable impurities, a microstructure of the base steel sheet contains 40% or more by total volume fraction of martensite and bainite, 8% or more by volume fraction of residual austenite, and a balance of the microstructure being ferrite or ferrite and 10% or less by volume fraction of pearlite.
    Type: Grant
    Filed: September 6, 2017
    Date of Patent: November 5, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Chisato Wakabayashi, Masafumi Azuma, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 10400301
    Abstract: The present invention relates to a high-strength steel sheet and, more specifically, to a dual-phase steel sheet having excellent formability, so as to be appropriately applied to vehicle panels and the like, and a manufacturing method therefor.
    Type: Grant
    Filed: November 26, 2015
    Date of Patent: September 3, 2019
    Assignee: POSCO
    Inventors: Sang-Ho Han, Yeon-Sang Ahn
  • Patent number: 10378077
    Abstract: A method for producing a cold rolled steel sheet having a tensile strength ?1470 MPa and a total elongation TE?19%, the method comprising the steps of annealing at an annealing temperature AT?Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%?C?0.40%, 1.50%?Mn?2.30%, 1.50?Si?2.40%, 0%<Cr?0.5%, 0%<Mo?0.3%, 0.01%?A1?0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 120 seconds.
    Type: Grant
    Filed: July 3, 2014
    Date of Patent: August 13, 2019
    Assignee: ArcelorMittal
    Inventors: Olga A. Girina, Damon Panahi
  • Patent number: 10344361
    Abstract: The present invention relates to an ultra-high strength, hot-dip galvanized steel sheet having excellent surface quality and coating adherence and to a method for manufacturing thereof, the ultra-high strength, hot-dip galvanized steel sheet comprising: 0.1-0.3% by weight carbon (C); 0.1-2.0% by weight silicon (Si); 0.005-1.5% by weight aluminum (Al); 1.5-3.5% by weight manganese (Mn); 0.04% by weight or less phosphorus (P) (excluding 0% by weight); 0.015% by weight or less sulphur (S) (excluding 0% by weight); 0.02% by weight or less nitrogen (N) (excluding 0% by weight); the balance being Fe; and other inevitable impurities, and further comprising 0.01 wt.% to 0.07 wt.% of at least one kind of element selected from the group consisting of bismuth (Bi), tin (Sn) and antimony (Sb).
    Type: Grant
    Filed: December 8, 2015
    Date of Patent: July 9, 2019
    Assignee: POSCO
    Inventors: Myung-Soo Kim, Ki-Cheol Kang
  • Patent number: 10344350
    Abstract: The present disclosure relates to a production of a high-strength steel sheet with excellent combination of strength and ductility, and a method of manufacturing the same. In accordance with a method of manufacturing a high-strength steel sheet, the method may include: heating a steel sheet which can have a residual austenite upon cooling, to form an austenite; primary cooling the austenitized steel sheet to T1 for a bainite region and subjecting to a primary isothermal transformation; and secondary cooling the primary isothermal transformed steel sheet to T2, which is lower than T1 by 50° C. ore more, for a bainite region, and subjecting to a secondary isothermal transformation.
    Type: Grant
    Filed: December 16, 2015
    Date of Patent: July 9, 2019
    Assignee: KOREA INSTITUTE OF MACHINERY AND MATERIALS
    Inventor: Chang-Hoon Lee
  • Patent number: 10301701
    Abstract: Disclosed is a high-strength hot-dip galvanized steel sheet produced from a steel sheet containing Si and Mn as a base material and a method for producing the same. The method using the following conditions for a heating process for annealing: (1) The rate of temperature rise when the temperature inside an annealing furnace is in a temperature range of from 450° C. to A° C. inclusive (where A is an arbitrary value selected in a range of 500?A) is 7° C./sec. or more; (2) The maximum steel sheet temperature reached during the annealing is 600° C. or higher and 750° C. or lower; (3) When the temperature of the steel sheet is in a temperature range of from 600° C. to 750° C. inclusive during the annealing, the transit time of the steel sheet is 30 seconds or longer and 10 minutes or shorter, and the dew point of an atmosphere is ?45° C. or lower.
    Type: Grant
    Filed: February 6, 2015
    Date of Patent: May 28, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Yusuke Fushiwaki, Yoshiyasu Kawasaki
  • Patent number: 10167541
    Abstract: Provided is an alloyed hot-dip galvanized steel sheet including a base steel sheet, the base steel sheet containing a given amount of C, Si, Mn, and other elements. The alloyed hot-dip galvanized steel sheet is provided with an alloyed hot-dip galvanized layer on a surface of the base steel sheet, the alloyed hot-dip galvanized layer containing, in mass %, Fe: more than or equal to 5% and less than or equal to 15%, and having a thickness of more than or equal to 3 ?m and less than or equal to 30 ?m.
    Type: Grant
    Filed: November 5, 2013
    Date of Patent: January 1, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Soshi Fujita, Shintaro Yamanaka
  • Patent number: 10106867
    Abstract: A steel strip is annealed in a vertical annealing furnace including a heating zone and a soaking zone through which the steel strip is vertically conveyed, an atmosphere gas is supplied into the furnace to form a furnace gas that is discharged from a steel strip entrance at a lower portion of the heating zone, a part of the furnace gas is sucked and discharged into a refiner to form a gas having a lowered dew point that is returned into the furnace. A gas injector having a plurality of gas outlets arranged in a direction of a travel of the steel strip is disposed to suppress a mixing of an atmosphere in the furnace upstream of the gas injector and an atmosphere in the furnace downstream of the gas injector, and a temperature of the steel strip passing through the gas injector is controlled to 600° C. to 700° C.
    Type: Grant
    Filed: June 10, 2013
    Date of Patent: October 23, 2018
    Assignee: JFE Steel Corporation
    Inventor: Hideyuki Takahashi
  • Patent number: 10087511
    Abstract: There are provided a method for manufacturing a high manganese hot-dip galvanized steel sheet having superior coatability and ultra-high strength, and a high manganese hot-dip galvanized steel sheet manufactured by the method. The method includes: cold rolling a hot-rolled steel sheet to form a cold-rolled steel sheet, the hot-rolled steel sheet including, by wt %, C: 0.3% to 1%, Mn: 8% to 25%, Si: 0.1% to 3%, Al: 0.01% to 8%, Cr: 0.1% to 2%, Ti: 0.01% to 0.2%, B: 0.0005% to 0.01%, Ni: 0.01% to 2%, Sn: 0.06% to 0.2%, and a balance of Fe and inevitable impurities; heating the cold-rolled steel sheet; cooling the heated steel sheet to, or maintaining the heated steel sheet; and performing a hot-dip galvanizing process on the cooled or temperature-maintained steel sheet by dipping the cooled or temperature-maintained steel sheet into a hot-dip galvanizing bath.
    Type: Grant
    Filed: December 19, 2013
    Date of Patent: October 2, 2018
    Assignee: POSCO
    Inventors: Sun-Ho Jeon, Kwang-Geun Chin, Won-Tae Cho
  • Patent number: 10030280
    Abstract: The present invention provides a steel sheet with chemical components including, by mass %, 0.18-0.35% of C, 1.0%-3.0% of Mn, 0.01%-1.0% of Si, 0.001%-0.02% of P, 0.0005%-0.01% of S, 0.001%-0.01% of N, 0.01%-1.0% of Al, 0.005%-0.2% of Ti, 0.0002%-0.005% of B, and 0.002%-2.0% of Cr, and the balance of Fe and inevitable impurities, wherein: by volume %, a fraction of the ferrite is 50% or more, and a fraction of a non-recrystallized ferrite is 30% or less; and Cr?/CrM is 2 or less, where Cr? is a concentration of Cr subjected to solid solution in iron carbide and CrM is a concentration of Cr subjected to solid solution in a base material, or Mn0/MnM is 10 or less, where Mn0 is a concentration of Mn subjected to solid solution in an iron carbide, and MnM is a concentration of Mn subjected to solid solution in a base material.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: July 24, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kunio Hayashi, Toshimitsu Aso, Toshimasa Tomokiyo
  • Patent number: 9994941
    Abstract: A high strength cold rolled steel sheet has a chemical composition including, by mass %, C: 0.06 to 0.13%, Si: 1.2 to 2.3%, Mn: 0.6 to 1.6%, P: not more than 0.10%, S: not more than 0.010%, Al: 0.01 to 0.10% and N: not more than 0.010%, the balance comprising Fe and inevitable impurities. The steel sheet includes a microstructure containing not less than 90% in terms of volume fraction of ferrite with an average grain diameter of less than 20 ?m and 1.0 to 10% in terms of volume fraction of pearlite with an average grain diameter of less than 5 ?m. The ferrite has an average Vickers hardness of not less than 130. The steel sheet has a yield ratio of not less than 65% and a tensile strength of not less than 590 MPa.
    Type: Grant
    Filed: December 3, 2012
    Date of Patent: June 12, 2018
    Assignee: JFE Steel Corporation
    Inventors: Katsutoshi Takashima, Yuki Toji, Kohei Hasegawa
  • Patent number: 9920407
    Abstract: A cold rolled steel sheet according to the present invention satisfies an expression of (5×[Si]+[Mn])/[C]>11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure before hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1<1.10 and ?HM<20 before the hot stamping, and TS×? which is a product of a tensile strength TS and a hole expansion ratio ? is 50000 MPa·% or more.
    Type: Grant
    Filed: January 11, 2013
    Date of Patent: March 20, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
  • Patent number: 9896751
    Abstract: High strength steel sheet and high strength galvanized steel sheet which are excellent in shapeability which secure a tensile maximum strength 900 MPa or more high strength while obtaining excellent ductility and stretch flangeability, which sheets have predetermined compositions of ingredients, have steel sheet structures which contain volume fraction 1 to 20% of residual austenite phases, and which have martensite transformation points of the residual austenite phases of ?60° C. or less.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: February 20, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Takeshi Yasui, Yuji Yamaguchi, Natsuko Sugiura
  • Patent number: 9828663
    Abstract: Provided is a galvannealed steel sheet with excellent anti-powdering property when press forming is performed, without controlling the contents of chemical elements in steel which are effective for strengthening a steel sheet, such as Si and P, to be low in order to achieve required material properties and without increasing cost due to, for example, processes being complicated. A galvannealed steel sheet with excellent anti-powdering property has a coated layer taking in grains of a base steel sheet such that the grains constitute 2.0% or more and 15.0% or less of the coated layer in terms of cross section area ratio.
    Type: Grant
    Filed: June 18, 2013
    Date of Patent: November 28, 2017
    Assignee: JFE Steel Corporation
    Inventors: Yoichi Makimizu, Yoshitsugu Suzuki, Hideki Nagano, Yasunobu Nagataki
  • Patent number: 9790567
    Abstract: A coated dual-phase steel and process for producing the coated dual-phase steel is provided. The process includes providing a steel slab with a desired chemistry, soaking the slab at an elevated temperature and then hot rolling the slab to produce hot-rolled strip. The hot-rolled strip is coiled and has a ferrite-pearlite microstructure. The coiled hot-rolled strip is cold-rolled into cold-rolled sheet with at least a 60% reduction in thickness compared to the thickness of the coiled hot-rolled strip. The cold-rolled sheet is subjected to an intercritical anneal followed by rapid cooling with the absence of an isothermal heat treatment or hold after rapid cooling near the molten metal pot temperature—during which, before or after which the steel is coated. The coated steel sheet has a dual-phase ferrite-martensite microstructure, a yield strength of at least 310 MPa, a tensile strength of at least 580 MPa and a total elongation to failure of at least 18%.
    Type: Grant
    Filed: November 20, 2013
    Date of Patent: October 17, 2017
    Assignee: Thyssenkrupp Steel USA, LLC
    Inventors: Ranbir Jamwal, Joseph Frimpong, Bertram Wilhelm Ehrhardt, Harald Van Bracht, Roger Dale Boggs, Stanley Wayne Bevans
  • Patent number: 9708684
    Abstract: There is provided a hot-dip galvanized steel sheet and a hot-dip galvannealed steel sheet, which have excellent elongation properties, and methods for manufacturing the hot-dip galvanized steel sheet and the hot-dip galvannealed steel sheet. The present disclosure relates to a hot-dip galvanized steel sheet in which a hot-dip galvanized layer is formed on a surface of a base steel sheet, the hot-dip galvanized steel sheet having excellent elongation properties and being characterized by the composition and the microstructure thereof.
    Type: Grant
    Filed: December 23, 2015
    Date of Patent: July 18, 2017
    Assignee: POSCO
    Inventors: Sang Ho Han, Seong Ho Han
  • Patent number: 9694561
    Abstract: High strength steel sheet which secures tensile maximum strength 900 MPa or more high strength while having excellent shapeability, which high strength steel sheet which is excellent in shapeability characterized by having a predetermined composition of ingredients, by the steel sheet structure including a ferrite phase and martensite phase, by the ratio of Cu particles incoherent with the bcc iron being 15% or more with respect to the Cu particles as a whole, by a density of Cu particles in the ferrite phase being 1.0×1018/m3 or more, and by an average particle size of Cu particles in the ferrite phase being 2.0 nm or more.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: July 4, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Masafumi Azuma, Takuya Kuwayama, Shigeru Yonemura
  • Patent number: 9598745
    Abstract: The present invention provides 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: October 21, 2011
    Date of Patent: March 21, 2017
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA, AISIN TAKAOKA CO., LTD.
    Inventors: Kunio Hayashi, Toshimitsu Aso, Toshimasa Tomokiyo, Hitoshi Tanino, Ryozo Wada
  • Patent number: 9551055
    Abstract: A high-strength hot-dip galvanized steel sheet containing a main component, the steel sheet having at least 40 wt. % of ferrite as a main phase in terms of the volumetric ratio, and 8-60% inclusive of residual austenite, the remaining structure comprising one or more of bainite, martensite, or pearlite. Austenite particles within a range where the average residual stress (sigmaR) thereof satisfies the expression ?400 MPa<=sigmaR<=200 MPa (formula (1)) are present in an amount of 50% or more in the hot-dip galvanized steel sheet. The surface of the steel sheet has a hot-dip galvanized layer containing less than 7 wt. % of Fe, the remainder comprising Zn, Al and inevitable impurities.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: January 24, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Koichi Sato, Shintaro Yamanaka, Soshi Fujita
  • Patent number: 9476111
    Abstract: A hot dip galvanized steel sheet includes a steel sheet, a hot dip galvanizing layer, and an intermetallic compound, in which the steel sheet has a chemical composition containing, by mass %, C: 0.03% or more and 0.70% or less, Si: 0.10% or less, Mn: 0.5% or more and 0.9% or less, P: 0.020% or more and 0.050% or less, S: 0.010% or less, Nb: 0.010% or more and 0.035% or less, N: 0.005% or less, Al: 0.10% or less, and the balance being Fe and inevitable impurities, in which the hot dip galvanizing layer contains 0.3% or more and 0.6% or less of Al, and in which the intermetallic compound contains 0.12 gm?2 or more and 0.22 gm?2 or less of Al and Fe2Al5 having an average grain diameter of 1 ?m or less.
    Type: Grant
    Filed: December 24, 2013
    Date of Patent: October 25, 2016
    Assignee: JFE Steel Corporation
    Inventors: Yoshitsugu Suzuki, Mai Miyata, Yasunobu Nagataki
  • Patent number: 9334555
    Abstract: Exemplary embodiments of the present invention can provide a hot dip galvannealed steel sheet which has excellent corrosion resistance, workability, coatability and appearance. The exemplary galvannealed sheet can include an ultra-low carbon steel sheet having a plating layer which includes about 8 to 13% Fe, about 0.05 to 1.0% Ni, about 0.15 to 1.5% Al, and a balance of Zn and unavoidable impurities. An exemplary method for producing a hot dip galvannealed steel sheet is also provided which can include cleaning an annealed ultra-low carbon steel sheet, preplating it with Ni, rapidly heating the sheet in a nonoxidizing or reducing atmosphere, plating the sheet in a galvanization bath containing Al, wiping it, then rapidly reheating it and either cooling the sheet without any soaking time or soaking and holding it for less than 15 seconds and then cooling it.
    Type: Grant
    Filed: January 17, 2013
    Date of Patent: May 10, 2016
    Assignee: NIPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kiyokazu Ishizuka, Kazumi Nishimura, Ikuo Kikuchi, Akihiro Miyasaka
  • Patent number: 9322091
    Abstract: There is provided a high-strength galvanized steel sheet including, on a mass percent basis, C: more than 0.060% and 0.13% or less, Si: 0.01% or more and 0.7% or less, Mn: 1.0% or more and 3.0% or less, P: 0.005% or more and 0.100% or less, S: 0.010% or less, sol.Al: 0.005% or more and 0.100% or less, N: 0.0100% or less, Nb: 0.005% or more and 0.10% or less, Ti: 0.03% or more and 0.15% or less, and the balance comprising Fe and incidental impurities, satisfying the relationship of (Nb/93+Ti*/48)/(C/12)>0.08 (wherein Ti*=Ti?(48/14)N?(48/32)S). The high-strength galvanized steel sheet has a structure including ferrite and martensite. The ferrite has an average grain diameter of 15 ?m or less and an area percentage of 80% or more. The martensite has an area percentage of 1% or more and 15% or less.
    Type: Grant
    Filed: January 28, 2013
    Date of Patent: April 26, 2016
    Assignee: JFE STEEL CORPORATION
    Inventors: Hideyuki Kimura, Katsutoshi Takashima, Shinjiro Kaneko
  • Patent number: 9290834
    Abstract: A galvanized steel sheet has a composition containing, by mass %, C: 0.05% or more and 0.5% or less, Si: 0.01% or more and 2.5% or less, Mn: 0.5% or more and 3.5% or less, P: 0.003% or more and 0.100% or less, S: 0.02% or less, Al: 0.010% or more and 0.5% or less, B: 0.0002% or more and 0.005% or less, Ti: 0.05% or less, a relationship of Ti>4N being satisfied, and the balance comprising Fe and inevitable impurities, and a microstructure containing 60% or more and 95% or less of tempered martensite in terms of area ratio and 5% or more and 20% or less of retained austenite in terms of area ratio.
    Type: Grant
    Filed: October 7, 2011
    Date of Patent: March 22, 2016
    Assignee: JFE Steel Corporation
    Inventors: Hiroshi Hasegawa, Tatsuya Nakagaito, Shinjiro Kaneko, Yasunobu Nagataki, Yoshitsugu Suzuki
  • Patent number: 9290835
    Abstract: The invention provides a cold-rolled steel sheet excellent in paint bake hardenability and ordinary-temperature non-aging property comprising, in mass %, C: 0.0005-0.0040%, Si: 0.8% or less, Mn: 2.2% or less, S: 0.0005-0.009%, Cr: 0.4-1.3%, O: 0.003-0.020%, P: 0.045-0.12%, B: 0.0002-0.0010%, Al: 0.008% or less, N: 0.001-0.007%, and a balance of Fe and unavoidable impurities. Ultra-low-carbon steel retaining solute N and containing added Cr, P, B and O is used to produce hot-rolled and cold-rolled steel sheet and hot-dip galvanized cold-rolled steel sheet that exhibit both high paint bake hardenability and ordinary-temperature non-aging property.
    Type: Grant
    Filed: October 5, 2005
    Date of Patent: March 22, 2016
    Assignee: Nippon Steel & Summitomo Metal Corporation
    Inventors: Naoki Yoshinaga, Naoki Maruyama, Manabu Takahashi, Natsuko Sugiura
  • Patent number: 9234253
    Abstract: A readily formable flat steel product has a ductile edge layer that is from 10 to 200 ?m thick and has a ductility greater than a ductility of an inner core layer of the flat steel product. The readily formable flat steel product is produced by annealing a flat steel product having a C content of from 0.1 to 0.4% by weight in a continuous furnace. The annealing is carried out under an annealing atmosphere that contains from 0.1 to 25% by vol. of H2 and H2O, with the balance being N2 and technically unavoidable impurities. A dew point is between ?20° C. and +60° C., and a ratio of H2O/H2 is a maximum of 0.957. In the course of the annealing, the flat steel product is heated to a holding temperature of from 600 to 1100° C. and for a holding time of from 10 to 360 seconds.
    Type: Grant
    Filed: December 3, 2010
    Date of Patent: January 12, 2016
    Assignee: ThyssenKrupp Steel Europe AG
    Inventors: Wilhelm Warnecke, Manfred Meurer, Jens Kondratiuk, Marc Blumenau, Martin Norden, Thiemo Wuttke
  • Patent number: 9181598
    Abstract: A high-strength alloyed hot-dip galvanized steel sheet obtained by subjecting the surface of a high-strength steel sheet to alloyed hot-dip galvanization, and formed from a steel sheet containing, in mass %, main components, and containing at least 40 vol % bainite and/or martensite, 8-60 vol % retained austenite, and less than 40 vol % ferrite, with the remainder comprising unavoidable structures. In the alloyed hot-dip galvanized steel sheet, the total thickness of the Gamma1 layer and the Gamma layer (Tgamma1+Tgamma) is 2 ?m or less in the alloy layers formed by hot-dip galvanization, and the Gamma1 phase/Gamma phase thickness ratio (Tgamma1/Tgamma) is 1 or less. A tensile strength of 980 MPa or above can be easily imparted to the alloyed hot-dip galvanized steel sheet. The alloyed hot-dip galvanized steel sheet has excellent coating adherence, and coating separation during machining can be suppressed.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: November 10, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shintaro Yamanaka, Soshi Fujita, Koichi Sato
  • Patent number: 9175374
    Abstract: A high strength hot-dip galvanized steel sheet has TS of 440 MPa or more and an average r value of 1.30 or more, where the absolute value of the planar anisotropy of the r value (?r) is 0.20 or less. A chemical composition contains C: 0.010% or more and 0.04% or less, Si: more than 1.0% and 1.5% or less, Mn: 1.0% or more and 3.0% or less, P: 0.005% or more and 0.1% or less, S: 0.01% or less, sol. Al: 0.005% or more and 0.5% or less, N: 0.01% or less, Nb: 0.010% or more and less than 0.05%, Ti: 0.015% or more and 0.120% or less, and the remainder composed of Fe and incidental impurities, wherein (Nb/93)/(C/12) 0.20 and 0.005<C*?0.020 are satisfied.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: November 3, 2015
    Assignee: JFE Steel Corporation
    Inventors: Hideyuki Kimura, Kaneharu Okuda, Yasunobu Nagataki, Kenji Kawamura
  • Patent number: 9163305
    Abstract: An annealing and manufacturing method of hot-dip galvanized steel strips includes suppression of oxide formation of elements in the steel strips. An annealing furnace includes a heating zone, a soaking zone, and a cooling zone in which a portion of gas is introduced to decrease the gas dew point. A gas suction rate Qo1 in a portion of the cooling zone, a gas suction rate Qo2 in an upper portion and a gas feed rate Qi2 in a lower portion of the soaking zone, a gas feed rate Qi1 in a connection part between the soaking and cooling zones, an atmosphere gas supply rate Qf1 into the cooling zone and its subsequent zone, an atmosphere gas supply rate Qf2 into the soaking zone, an internal volume Vs of the soaking zone, and an average furnace temperature Ts of the soaking zone satisfy relationships including 0.3×Qf1<Qo1.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: October 20, 2015
    Assignee: JFE STEEL CORPORATION
    Inventors: Hideyuki Takahashi, Nobuyuki Sato, Kazuki Nakazato, Masato Iri
  • Patent number: 9150940
    Abstract: A high-strength alloyed hot-dip galvanized steel sheet obtained by subjecting the surface of a high-strength steel sheet to alloyed hot-dip galvanization, and formed from a steel sheet containing, in mass %, main components, and containing at least 40 vol % bainite and/or martensite, 8-60 vol % retained austenite, and less than 40 vol % ferrite, with the remainder comprising unavoidable structures. In the alloyed hot-dip galvanized steel sheet, the total thickness of the Gamma1 layer and the Gamma layer (Tgamma1+Tgamma) is 2 ?m or less in the alloy layers formed by hot-dip galvanization, and the Gamma1 phase/Gamma phase thickness ratio (Tgamma1/Tgamma) is 1 or less. A tensile strength of 980 MPa or above can be easily imparted to the alloyed hot-dip galvanized steel sheet. The alloyed hot-dip galvanized steel sheet has excellent coating adherence, and coating separation during machining can be suppressed.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: October 6, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shintaro Yamanaka, Soshi Fujita, Koichi Sato
  • Patent number: 9127329
    Abstract: A method for manufacturing a coated part having very high mechanical properties using hot forming techniques. The method includes: —providing an annealed steel strip or blank or pre-shaped part that was coated with a metal or metal alloy before the annealing —if a strip is provided, cutting a blank from the strip before or after the annealing —optionally forming a pre-shaped part from the blank —heating the blank or preshaped part to a temperature of 500° C. at an average heating rate of 16° C./s or more —further heating the blank or pre-shaped part to a temperature between 700 and 1000° C. —hot forming the blank or preshaped part into a hot formed part —hardening the hot formed part. A method for manufacturing a coated steel strip, blank or pre-shaped part, and a coated steel strip, blank or part and a hot formed part.
    Type: Grant
    Filed: July 19, 2011
    Date of Patent: September 8, 2015
    Assignee: TATA STEEL IJMUIDEN B.V.
    Inventors: Willem Cornelis Verloop, Marc Jacco van Genderen, Ronald Theodoor van Tol, Guido Cornelis Hensen, Jenny Loiseaux
  • Patent number: 9096918
    Abstract: Exemplary embodiments of a facility or an arrangement capable of producing a high strength steel sheet or a hot dip zinc coated high strength steel sheet according to the present invention are provided which can make a quenching facility and tempering facility continuous treatment facilities. For example, an improvement in the material quality can be effectuated due to tempering enable improvement of the hole expandability. In addition, an elongation of the sheet can be improved.
    Type: Grant
    Filed: November 9, 2005
    Date of Patent: August 4, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hirokazu Taniguchi, Toshiki Nonaka, Hiroki Murayama, Koji Yanaba, Satoshi Kato
  • Patent number: 9090960
    Abstract: A strain aging hardening type steel sheet excellent in aging resistance, and manufacturing method thereof, said steel sheet comprises: in mass %, C: 0.0010 to 0.010%; Si: 0.005 to 1.0%; Mn: 0.08 to 1.0%; P: 0.003 to 0.10%; S: 0.0005 to 0.020%; Al: 0.010 to 0.10%; Cr: 0.005 to 0.20%; Mo: 0.005 to 0.20%; Ti: 0.002 to 0.10%; Nb: 0.002 to 0.10%; N: 0.001 to 0.005%; and a balance being composed of Fe and inevitable impurities, in which a ferrite fraction is 98% or more, an average grain diameter of ferrite is 5 to 30 ?m, a minimum value of dislocation density in a portion having a ½ thickness of a sheet thickness and a minimum value of dislocation density in a surface layer portion are each 5×1012/m2 or more, and an average dislocation density falls within a range of 5×1012 to 1×1015/m2.
    Type: Grant
    Filed: June 22, 2011
    Date of Patent: July 28, 2015
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Naoki Maruyama, Koji Hashimoto, Masaharu Kameda
  • Patent number: 9073292
    Abstract: A high strength galvanized steel sheet includes a steel sheet which is a base sheet and a galvanized layer on a surface of the steel sheet, the steel sheet has a composition including, by mass %, 0.08 to 0.15% of C, 0.5 to 1.5% of Si, 0.5 to 1.5% of Mn, 0.1% or less of P, 0.01% or less of S, 0.01 to 0.1% of Al, 0.005% or less of N, and the balance Fe with inevitable impurities, and a microstructure composed of 75 to 90% of a ferrite phase as a main phase and 10 to 25% of a second phase including at least pearlite in terms of an area fraction with respect to the entire microstructure; an average grain size of the pearlite is 5 ?m or smaller; and the pearlite has an area fraction of 70% or greater with respect to the total area of the second phase.
    Type: Grant
    Filed: June 29, 2011
    Date of Patent: July 7, 2015
    Assignee: JFE Steel Corporation
    Inventors: Kenji Kawamura, Hidetaka Kawabe, Kazuhiro Seto
  • Publication number: 20150147589
    Abstract: A rolled steel sheet or blank is provided, the composition of which comprises the elements listed below in per cent by weight: C?0.1%; 0.5%?Mn?7%; 0.5%?Si?3.5%; 0.5%<Ti?2%; 2%<Ni?7%; Al?0.10%; Cr?2%; Cu?2%; Co?2%; Mo?2%; S?0.005%; P?0.03%; Nb?0.1%; V?0.1%; B<0.005%; N?0.008%, and the silicon and titanium contents are such that: Si + Ti ? 2.5 ? % , Ti Si ? 0.3 the remainder of the composition consisting of iron and unavoidable impurities resulting from processing. A method for the fabrication of a part for a land motor vehicle from the sheet or blank by hot stamping is also provided. The microstructure of the part consisting essentially of martensite and intermetallic precipitates of type Fe2TiSi with an area percentage between 1 and 5% intermetallic precipitates.
    Type: Application
    Filed: September 6, 2011
    Publication date: May 28, 2015
    Applicant: Arcelormittal Investigacion Y Desarrollo, S.L.
    Inventors: Olivier Bouaziz, David Barbier, Coralie Jung
  • Patent number: 9028626
    Abstract: A method of manufacturing a high-strength galvanized steel sheet includes hot-rolling a slab to form a steel sheet; during continuous annealing, heating the steel sheet to a temperature of 750° C. to 900° C. at an average heating rate of at least 10° C./s at a temperature of 500° C. to an A1 transformation point; holding that temperature for at least 10 seconds; cooling the steel sheet from 750° C. to a temperature of (Ms point—100° C.) to (Ms point—200° C.) at an average cooling rate of at least 10° C./s; reheating the steel sheet to a temperature of 350° C. to 600° C.; holding that temperature for 10 to 600 seconds; and galvanizing the steel sheet.
    Type: Grant
    Filed: March 25, 2013
    Date of Patent: May 12, 2015
    Assignee: JFE Steel Corporation
    Inventors: Tatsuya Nakagaito, Saiji Matsuoka, Shinjiro Kaneko, Yoshiyasu Kawasaki, Yoshitsugu Suzuki
  • Publication number: 20150125716
    Abstract: Provided is a method for producing a plated steel sheet with high Si content for hot stamping, which is capable of suppressing the generation of unplated portions, while maintaining high bonding strength in a welded part in cases where a galvanized steel sheet containing a large amount of Si, namely, 0.7% or more of Si is used for hot stamping applications. In this production method, a hot-rolled pickled steel sheet or cold-rolled steel sheet containing 0.10-0.5% by mass of C, 0.7-2.5% by mass of Si, 1.0-3% by mass of Mn, and 0.01-0.5% by mass of Al is annealed in a reducing atmosphere and then plated, thereby producing a galvanized steel sheet for hot stamping. This method for producing a galvanized steel sheet for hot stamping is characterized in that the annealing is carried out within the range of 500 to 700° C. for 30 to 270 seconds.
    Type: Application
    Filed: April 23, 2013
    Publication date: May 7, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takeshi Kojima, Hiroshi Irie, Takeshi Minowa