Heating Step Follows Cold Working Patents (Class 148/651)
  • Patent number: 10954578
    Abstract: Disclosed is a steel sheet having a predetermined chemical composition and a steel microstructure that contains, in area ratio, 35% or more and 80% or less of polygonal ferrite and 5% or more and 25% or less of martensite, and that contains, in volume fraction, 8% or more of retained austenite, in which the polygonal ferrite, the martensite, and the retained austenite have a mean grain size of 6 ?m or less, 3 ?m or less, and 3 ?m or less, respectively, and each have a mean grain aspect ratio of 2.0 or less, and in which a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more.
    Type: Grant
    Filed: October 29, 2015
    Date of Patent: March 23, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Yoshiyasu Kawasaki, Hiroshi Matsuda, Takeshi Yokota, Takako Yamashita, Kazuhiro Seto
  • Patent number: 10450642
    Abstract: A high-strength galvanized steel sheet that includes a chemical composition containing, by mass %, C: 0.15% or more and 0.25% or less, Si: 0.50% or more and 2.5% or less, Mn: 2.3% or more and 4.0% or less, P: 0.100% or less, S: 0.02% or less, Al: 0.01% or more and 2.5% or less, and Fe and inevitable impurities. The steel sheet having a microstructure containing, by an area percentage basis, a tempered martensite phase: 30% or more and 73% or less, a ferrite phase: 25% or more and 68% or less, a retained austenite phase: 2% or more and 20% or less, and other phases: 10% or less (including 0%), the other phases containing a martensite phase: 3% or less (including 0%) and a bainitic ferrite phase: less than 5% (including 0%).
    Type: Grant
    Filed: November 24, 2015
    Date of Patent: October 22, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Hiroshi Hasegawa, Hideyuki Kimura, Yoshimasa Funakawa, Yoichi Makimizu, Yoshitsugu Suzuki
  • Patent number: 10329635
    Abstract: A high strength cold-rolled steel sheet has a component composition containing specific amounts of C, Si, Mn, P, S, N and Al, respectively with a remainder being iron and inevitable impurities. The steel sheet contains 95% or more of martensite in terms of area ratio, and contains 5% or less (inclusive of 0%) of residual austenite and ferrite in terms of a total area ratio. An average size of a carbide is 60 nm or less in terms of an equivalent circle diameter, and a number density of the carbide having the equivalent circle diameter of 25 nm or more is 5.0×105 pieces or less per mm2. The steel sheet has a yield strength of 1,180 MPa or more and a tensile strength of 1,470 MPa or more.
    Type: Grant
    Filed: February 13, 2014
    Date of Patent: June 25, 2019
    Assignee: Kobe Steel, Ltd.
    Inventors: Kosuke Shibata, Toshio Murakami, Elijah Kakiuchi, Katsura Kajihara
  • Patent number: 10155256
    Abstract: The invention relates to a metal strip which is produced from steel by hot rolling and by cold rolling of the metal strip. The invention also relates to a blank produced from the metal strip, the use of the metal strip, and to a method of producing it. The object of providing metal strip from which components of minimum weight which are adapted to specific loads can be produced with little cost or complication is achieved by metal strip of the generic kind which, after the cold rolling, is of constant thickness and has, section by section, regions whose mechanical properties vary. What “after the cold rolling” means, for the purposes of the present invention, is that, immediately on completion of the cold rolling, i.e. without any further treatment such as heat treatment, regions whose mechanical properties vary are present in the metal strip.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: December 18, 2018
    Assignee: ThyssenKrupp Steel Europe AG
    Inventors: Jens-Ulrik Becker, Harald Hofmann
  • Patent number: 10041158
    Abstract: A multi-phase hot-rolled steel sheet having improved strength in an intermediate strain rate region has a chemical composition comprising, in mass percent, C: 0.07-0.2%, Si+Al: 0.3-1.5%, Mn: 1.0-3.0%, P: at most 0.02%, S: at most 0.005%, Cr: 0.1-0.5%, N: 0.001-0.008%, at least one of Ti: 0.002-0.05% and Nb: 0.002-0.05%, and a remainder of Fe and impurities. The area fraction of ferrite is 7-35%, the grain diameter of ferrite is in the range of 0.5-3.0 ?m, and the nanohardness of ferrite is in the range of 3.5-4.5 GPa. A second phase which is the remainder other than ferrite contains martensite and bainitic ferrite and/or bainite. The average nanohardness of the second phase is 5-12 GPa, and the second phase contains a high-hardness phase of 8-12 GPa with an area fraction of 5-35% based on the overall structure.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: August 7, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yasuaki Tanaka, Toshiro Tomida, Kaori Kawano
  • Patent number: 9657381
    Abstract: This high-strength steel plate has a component composition including, by mass %, C: 0.02-0.3%, Si: 1-3%, Mn: 1.8-3%, P: 0.1% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.002-0.03%, the rest consisting of iron and impurities. Said steel plate has a microstructure including, in terms of area ratio relative to the entire microstructure, each of the following phases: bainitic ferrite: 50-85%; retained ?: 3% or greater; martensite+the aforementioned retained ?: 10-45%; and ferrite: 5-40%. The C concentration (C?R) in the aforementioned retained austenite is 0.3-1.2 mass %, part or all of the N in the aforementioned component composition is solid solution N, and the amount of said solid solution N is 30-100 ppm.
    Type: Grant
    Filed: August 15, 2012
    Date of Patent: May 23, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Toshio Murakami, Elijah Kakiuchi, Hideo Hata, Naoki Mizuta, Tatsuya Asai
  • Patent number: 9623457
    Abstract: The present invention discloses a double cold reduction strip for shadow mask and a process for producing the same, comprising the following procedures: converter steelmaking?continuous billet casting?hot rolling?pickling and cold rolling?continuous annealing?double cold reduction?finishing and oiling. The weight percentages of essential elements of the shadow mask strip are: C: ?0.001%, Mn: 0.10˜0.40%, Al: 0.02˜0.06%, Si: ?0.025%, P: ?0.015%, S: ?0.01%, O: ?0.004%, with remainders composed of Fe and inevitable impurities.
    Type: Grant
    Filed: May 17, 2013
    Date of Patent: April 18, 2017
    Assignee: BAOSHAN IRON & STEEL CO., LTD.
    Inventors: Shoumin Wu, Xiujun Li
  • Patent number: 9387506
    Abstract: A process for preparing a ceramic body having a surface roughness, said process comprising the step of depositing particles of a ceramic material on the surface of a ceramic basic body. The process is characterized in that separate agglomerates comprising at least two particles and a binder binding the particles together are deposited on the surface of the basic body by projecting the agglomerates towards the basic body.
    Type: Grant
    Filed: December 4, 2014
    Date of Patent: July 12, 2016
    Assignee: STRAUMANN HOLDING AG
    Inventor: Marc Stephan
  • Patent number: 9205512
    Abstract: A process is provided for laser beam welding of surface treated steel components. Two steel components, at least one of which is a surface treated steel component, are relatively arranged to form a joint that is to be welded. Using a laser beam, the two steel components are irradiated along the joint so as to heat materials within each of the two steel components to a welding temperature, and thereby form a weld pool. During welding a metallic constituent is introduced into a leading edge of the weld pool, in front of the laser beam along a welding direction. The introduced metallic constituent combines with a species, which is released into the weld pool from the surface treated steel component, to form a compound that is stable within the weld pool at the welding temperature.
    Type: Grant
    Filed: December 19, 2011
    Date of Patent: December 8, 2015
    Assignee: MAGNA INTERNATIONAL INC.
    Inventors: Hongping Gu, Guobin Yin, Boris Shulkin
  • Patent number: 9057123
    Abstract: Provided is a hot-rolled steel sheet that has a chemical composition including, by mass %: C: 0.060% to 0.150%; Si: 0.15% to 0.70%; Mn: 1.00% to 1.90%; P: 0.10% or less; S: 0.010% or less; Al: 0.01% to 0.10%; N: 0.010% or less; Nb: 0.010% to 0.100%; and the balance including Fe and incidental impurities. The hot-rolled steel sheet has a microstructure containing ferrite of 18 ?m or less in average grain size by a volume fraction of at least 75% and pearlite of at least 2 ?m in average grain size by a volume fraction of at least 5%, the balance being low-temperature-induced phases, the pearlite having a mean free path of at least 5.0 ?m.
    Type: Grant
    Filed: September 27, 2012
    Date of Patent: June 16, 2015
    Assignee: JFE Steel Corporation
    Inventors: Katsutoshi Takashima, Yuki Toji, Kohei Hasegawa
  • 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
  • Patent number: 8876987
    Abstract: A high strength pressed member has excellent ductility and stretch flangeability and tensile strength of 780-1400 MPa, with a predetermined steel composition and steel microstructure relative to the entire microstructure of steel sheet, where area ratio of martensite 5-70%, area ratio of retained austenite 5-40%, area ratio of bainitic ferrite in upper bainite 5% or more, and total thereof is 40% or more, 25% or more of martensite is tempered martensite, polygonal ferrite area ratio is above 10% and below 50% to the entire microstructure of steel sheet, and average grain size is 8 ?m or less, average diameter of a group of polygonal ferrite grains is 15 ?m or less, the group of polygonal ferrite grains represented by a group of ferrite grains of adjacent polygonal ferrite grains, and average carbon content in retained austenite is 0.70 mass % or more and tensile strength is 780 MPa or more.
    Type: Grant
    Filed: October 2, 2012
    Date of Patent: November 4, 2014
    Assignee: JFE Steel Corporation
    Inventors: Hiroshi Matsuda, Yoshimasa Funakawa, Kaneharu Okuda, Kazuhiro Seto
  • Patent number: 8864922
    Abstract: A method for manufacturing a precipitation hardening cold-rolled steel sheet with an excellent yield ratio. The method may include the steps of hot rolling a steel slab with finish rolling at a temperature of Ar3 transformation point or more to form a hot-rolled steel sheet, coiling the hot-rolled steel sheet at a temperature of 550-600 ° C., cold rolling the hot-rolled steel sheet at a reduction ratio of 50% or more; and recovery-recrystallization annealing the cold-rolled steel sheet at a line speed of 150-200 mpm and at a temperature of 780-820° C. in a continuous annealing furnace. The recovery-recrystallization annealing may provide a recrystallization ratio of 65-75%. The steel slab includes, by weight %: C: 0.07-0.10%, Mn: 1.41-1.70%, P: 0.05-0.07%, S: 0.005% or less, N: 0.005% or less, acid-soluble Al: 0.10-0.15%, Nb: 0.06-0.09%, B: 0.0008-0.0012%, Sb: 0.02-0.06%, and the balance comprising Fe and other unavoidable impurities.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: October 21, 2014
    Assignee: POSCO
    Inventor: Sang-Ho Han
  • Publication number: 20140290810
    Abstract: A high strength cold rolled steel sheet includes a chemical composition containing, by mass %, C: 0.010% or more and 0.060% or less, Si: more than 0.5% and 1.5% 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 0.500% or less, N: 0.0100% or less, Nb: 0.010% or more and 0.100% or less, Ti: 0.015% or more and 0.150% or less and the balance comprising Fe and inevitable impurities. The microstructure includes, in area fraction, 70% or more of a ferrite phase and 3% or more of a martensite phase. The tensile strength is 440 MPa or more and an average r value is 1.20 or more.
    Type: Application
    Filed: August 23, 2012
    Publication date: October 2, 2014
    Applicant: JFE STEEL CORPORATION
    Inventors: Hideyuki Kimura, Yasunobu Nagataki, Kaneharu Okuda, Kenji Kawamura
  • Publication number: 20140283953
    Abstract: Method for producing a soft magnetic alloy strip suited to be mechanically cut, having a chemical composition comprising, by weight: 18% ?? Co ? 55%? 0% ? V + W ? 3% 0% ? Cr ? 3% 0% ? Si ? 3% 0% ? Nb ? 0.5%? 0% ? B ? 0.05%?? 0% ? C ? 0.1%? 0% ? Zr + Ta ? 0.5%? 0% ? Ni ? 5% 0% ? Mn ? 2% the rest being iron and impurities from production, according to which a strip obtained by hot rolling a semi-finished product consisting of the alloy is cold-rolled to obtain a cold-rolled strip with a thickness less than 0.6 mm, After the cold rolling, the strip is running annealed by passing it through a continuous furnace at a temperature between the order/disorder transition temperature of the alloy and the ferritic/austenitic transformation point of the alloy, followed by rapid cooling to a temperature below 200° C.
    Type: Application
    Filed: December 16, 2011
    Publication date: September 25, 2014
    Applicant: APERAM
    Inventors: Thierry Waeckerle, Remy Batonnet
  • Publication number: 20140238557
    Abstract: A method for producing a high-tensile cold-rolled steel sheet includes subjecting a slab having a composition containing C: more than 0.020% and less than 0.30%, Si: more than 0.10% and 3.00% or less, and Mn: more than 1.00% and 3.50% or less to hot rolling wherein the roll draft of the final one pass is higher than 15%, and rolling is finished in the temperature region of Ar3 point or higher, optionally annealing wherein the hot-rolled steel sheet is heated to 300° C. or higher after being cooled to 780° C. or lower, coiling higher than 400° C. or lower than 400° C., cold rolling the hot-rolled steel sheet or the annealed steel sheet, and annealing wherein the cold-rolled steel sheet is soaked in the temperature region of (Ac3 point?40° C.) or higher, cooling to 500° C. or lower and 300° C. or higher, and holding in that temperature region for 30 seconds or longer.
    Type: Application
    Filed: July 2, 2012
    Publication date: August 28, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Jun Haga, Takuya Nishio, Masayuki Wakita, Yasuaki Tanaka, Norio Imai, Toshiro Tomida, Mitsuru Yoshida, Kengo Hata
  • Patent number: 8721960
    Abstract: The present invention provides a ferritic stainless steel comprised of, by mass %, C: 0.001 to 0.02%, Si: 0.01 to 0.6%, Mn: 0.01 to 0.6%, P: 0.005 to 0.04%, S: 0.0001 to 0.01%, Cr: 13 to 22%, N: 0.001 to 0.02%, Al: 0.005 to 0.05%, Sn: 0.001 to 1%, and a balance of Fe and unavoidable impurities, which steel satisfies the following formulae: 0<I(Fe)/I(Cr)<5 and 0<I(O)/I(Sn)<3, where I(Fe), I(Cr), I(Sn), and I(O) are the X-ray intensities of the Fe oxides, Cr oxides, Sn oxides, and the sum of X-ray intensities other detected oxides at the steel surface measured by an X-ray photoelectron spectrometer. The present invention also provides a method of producing the ferritic stainless steel.
    Type: Grant
    Filed: December 7, 2009
    Date of Patent: May 13, 2014
    Assignee: Nippon Steel & Sumikin Stainless Steel Corporation
    Inventors: Masaharu Hatano, Akihiko Takahashi, Eiichiro Ishimaru, Shigenori Takahata
  • Patent number: 8702875
    Abstract: The present disclosure relates to a high strength steel sheet having good wettability, a tensile strength of 590 MPa or more and a strength-ductility balance (TS×El) of 16,520 MPa·% or more, and a manufacturing method thereof. The high strength steel comprises, in % by weight, C: 0.03˜0.1%, Si: 0.005˜0.105%, Mn: 1.0˜3.0%, P: 0.005˜0.04%, S: 0.003% or less, N: 0.003˜0.008%, Al: 0.05˜0.4%, Mo or Cr satisfying the inequality 10?50·[Mo %]+100·[Cr %]?30, at least one of Ti: 0.005˜0.020%, V: 0.005˜0.050% and B: 0.0005˜0.0015%, and the balance of Fe and unavoidable impurities, wherein a microstructure of the steel sheet is a multi-phase structure comprising, in an area ratio of cross-sectional structure, 70% or more ferrite phase having a Vickers hardness Hv of 120˜250 and 10% or more martensite phase having a Vickers hardness Hv of 321˜555.
    Type: Grant
    Filed: April 16, 2010
    Date of Patent: April 22, 2014
    Assignee: Hyundai Steel Company
    Inventors: Hoon-Dong Kim, Hyun-Ho Bok, Kang-Roh Lee, Man-Been Moon
  • Patent number: 8657969
    Abstract: A high strength galvanized steel sheet has a TS of 590 MPa or more and excellent processability. The component composition contains, by mass %, C: 0.05% to 0.3%, Si: 0.7% to 2.7%, Mn: 0.5% to 2.8%, P: 0.1% or lower, S: 0.01% or lower, Al: 0.1% or lower, and N: 0.008% or lower, and the balance: Fe or inevitable impurities. The microstructure contains, in terms of area ratio, ferrite phases: 30% to 90%, bainite phases: 3% to 30%, and martensite phases: 5% to 40%, in which, among the martensite phases, martensite phases having an aspect ratio of 3 or more are present in a proportion of 30% or more.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: February 25, 2014
    Assignee: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Tatsuya Nakagaito, Shinjiro Kaneko, Saiji Matsuoka
  • Patent number: 8641835
    Abstract: An iron alloy according to the present invention comprises: Al in an amount of from 3 to 5.5%; Mn in an amount from 0.2 to 6%; and the balance being iron (Fe), and inevitable impurities and/or a modifying element; when the entirety is taken as 100%. Since a high damping factor is obtainable at a low-strain amplitude, this iron alloy demonstrates a stable damping property even in a high-temperature region. Moreover, since the alloying elements are Al and Mn alone, and since their contents are less, the iron alloy according to the present invention is low in cost.
    Type: Grant
    Filed: September 8, 2009
    Date of Patent: February 4, 2014
    Assignee: Kabushiki Kaisha Toyota Jidoshokki
    Inventors: Keita Yamana, Motoharu Tanizawa, Masanori Harata, Kyoichi Kinoshita
  • Patent number: 8460481
    Abstract: The invention is directed to providing, for application in automobiles, construction materials, household appliances and the like, high-strength sheets excellent in formability properties such as hole expansibility and ductility, and also in fatigue resistance, characterized in comprising, in specified contents expressed in mass %, C, Si, Mn, P, S, Al, N and O and a balance of iron and unavoidable impurities, and having a steel sheet structure composed mainly of ferrite and hard structures, a crystal orientation difference between some ferrite adjacent to hard structures and the hard structures of less than 9°, and a maximum tensile strength of 540 MPa or greater.
    Type: Grant
    Filed: April 9, 2009
    Date of Patent: June 11, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Masafumi Azuma, Noriyuki Suzuki, Naoki Maruyama, Naoki Yoshinaga, Akinobu Murasato
  • Patent number: 8449700
    Abstract: Disclosed are a high-strength, high-toughness hot-pressed steel plate member and a manufacturing method therefor. A specified hot-press process is performed on a steel plate member that, with respect to the chemical composition of the steel plate, includes: 0.15 to 0.4 wt % of C; 1.0 to 5.0 wt % of Mn or of a total of Mn and at least one of Cr, Mo, Cu, and Ni; 0.02 to 2.0 wt % of at least any one of Si and Al; and the remainder being Fe and unavoidable impurities, thus providing the physical properties of a martensite phase average grain diameter of 5 ?m or less and a tensile strength of 1200 MPa or higher.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: May 28, 2013
    Assignee: National University Corporation Okayama University
    Inventors: Takehide Senuma, Hiroshi Yoshida
  • Patent number: 8444782
    Abstract: Provided is a method of manufacturing a high strength ferritic/martensitic steel. The method includes melting a ferritic/martensitic steel, hot-working the melted ferritic/martensitic steel, normalizing the hot-worked ferritic/martensitic steel at a temperature of about 1050° C. to about 1200° C., tempering the ferritic/martensitic steel at a temperature of about 600° C. or less, and leaving MX precipitates while preventing a M23C6 precipitate from being precipitated, and cold-working and thermal-treating the ferritic/martensitic steel in a multistage fashion, and precipitating M23C6 precipitates. Through the above described configuration, the high strength ferritic/martensitic steel that prevents a ductility from being deteriorated even in a high-temperature environment may be manufactured.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: May 21, 2013
    Assignee: Korea Atomic Energy Research Institute
    Inventors: Woo-Gon Kim, Chan-Bock Lee, Jong-Hyuk Baek, Do-Hee Hahn, Sung-Ho Kim, Chang-Hee Han, Tae-Kyu Kim, Jun-Hwan Kim
  • Patent number: 8440030
    Abstract: A method for manufacturing a fine spheroidized steel sheet having an excellent heat treatment characteristic, the method including: i) manufacturing a high carbon slab that is formed of 0.3 to 1.0 wt % C, 0.1 to 1.2 wt % Mn, 0 to 0.4 wt % Si, 0.01 to 0.1 wt % Al, 0 to 0.01 wt % S, and balance Fe and an inevitably added impurity as residuals; ii) reheating the slab to a temperature of Ar3 transformation point or more; iii) roughing rolling the slab, and manufacturing a thin plate by performing finish rolling in an austenite region; iv) cooling the thin plate at a cooling speed of 50 to 300° C./sec; v) finishing the cooling of the thin plate at a temperature region of 400 to 650° C. and maintaining the temperature; vi) winding the thin plate at a temperature region of 450 to 700° C.; vii) performing cold rolling at a reduction ratio of 30% or more; and viii) spheroidizing annealing the cold rolled thin plate.
    Type: Grant
    Filed: December 21, 2009
    Date of Patent: May 14, 2013
    Assignee: POSCO
    Inventors: Chang-Hoon Lee, Jea-Chun Jeon, Jong-Sub Lee, Ki-Soo Kim
  • Patent number: 8372221
    Abstract: A method provides a slab by continuous casting of a steel having a component composition of, in mass %, C: 0.005% or less, Mn: 0.05 to 0.5%, Al: 0.01 to 0.10%, N: 0.0010 to 0.0070%, B: 0.15×N to 0.75×N (0.15 to 0.75 in terms of B/N), and one or both of Nb: 4×C to 20×C (4 to 20 in terms of Nb/C) and Ti: 2×C to l0×C (2 to 10 in terms of Ti/C), and the balance of Fe and inevitable impurity elements; rough rolling the slab; finish rolling the rough-rolled slab wherein 5% or more and less than 50% of the total amount of rolling reduction in the finish rolling is hot-rolled at a temperature lower than the Ar3 transformation point; winding the hot-rolled steel sheet at a winding temperature of 640 to 750 ° C.; pickling the coiled steel sheet; cold rolling the pickled steel sheet at a rolling reduction rate of 88 to 96%; and annealing the cold-rolled steel sheet in a temperature range of higher than 400 ° C. to a temperature that is 20 ° C. lower than the recrystallization temperature.
    Type: Grant
    Filed: December 22, 2009
    Date of Patent: February 12, 2013
    Assignee: JFE Steel Corporation
    Inventors: Katsumi Kojima, Takumi Tanaka, Masaki Tada, Makoto Aratani, Hiroki Iwasa
  • Patent number: 8303733
    Abstract: This stainless steel sheet includes, in terms of mass %, C: 0.001 to 0.1%, N: 0.01 to 0.15%, Si: 0.01 to 2%, Mn: 0.1 to 10%, P: 0.05% or less, S: 0.01% or less, Ni: 0.5 to 5%, Cr: 10 to 25%, and Cu: 0.5 to 5%, with a remainder being Fe and unavoidable impurities, and contains a ferrite phase as a main phase and 10% or more of an austenite phase, wherein a work-hardening rate in a strain range of up to 30% is 1000 MPa or more which is measured by a static tensile testing and a difference between static and dynamic stresses which occur when 10% of deformation is caused is 150 MPa or more. This method for producing a stainless steel includes annealing a cold-rolled steel sheet under conditions where a holding temperature is set to be in a range of 950 to 1150° C. and a cooling rate until 400° C. is set to be in a range of 3° C./sec or higher.
    Type: Grant
    Filed: January 22, 2009
    Date of Patent: November 6, 2012
    Assignee: Nippon Steel & Sumikin Stainless Steel Corporation
    Inventors: Junichi Hamada, Haruhiko Kajimura, Eiichiro Ishimaru
  • Patent number: 8298356
    Abstract: The ultrahigh-strength steel sheet contains, in mass %, C: 0.05-0.25%, Si: 1.00-2.5%, Mn: 2.0-4.0%, P: 0.1% or below (not inclusive of 0%), S: 0.05% or below (not inclusive of 0%), Al: 0.01-0.15%, Ti: 0.003-0.10%, N: 0.01% or below (not inclusive of 0%), the balance comprising iron with inevitable impurities, and is a composite structure steel sheet comprising 10-50 area % ferrite and 50 area % or above martensite, in which the average circle-equivalent grain diameter of ferrite grains is 2.0 ?m or below, the average aspect ratio of ferrite grains is 2.0 or below, and the tensile strength is 1,100 MPa or above. Accordingly, the ultrahigh-strength steel sheet is excellent in hydrogen embrittlement resistance and workability.
    Type: Grant
    Filed: November 2, 2009
    Date of Patent: October 30, 2012
    Assignee: Kobe Steel, Ltd.
    Inventors: Muneaki Ikeda, Yukihiro Utsumi
  • Patent number: 8262815
    Abstract: The present invention provides high purity ferrite stainless steel able to reduce deterioration in surface conditions due to pitting corrosion or rusting or other corrosion to an extent no different from SUS304 or better without inviting a drop in manufacturability or workability and without relying on the addition of rare elements, and a method of production of the same, that is, ferritic stainless steel containing, by mass %, C: 0.01% or less, Si: 0.01 to 0.20%, Mn: 0.01 to 0.30%, P: 0.04% or less, S: 0.01% or less, Cr: 13 to 22%, N: 0.001 to 0.020%, Ti: 0.05 to 0.35%, Al: 0.005 to 0.050%, Sn: 0.001 to 1%, and a balance of Fe and unavoidable impurities to which Sn is added to modify the passive film and improve the corrosion resistance. To improve the effect of modification of the passive film by the addition of Sn, after the final annealing, the steel is held in the 200 to 700° C. temperature range for 1 minute or more.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: September 11, 2012
    Assignee: Nippon Steel & Sumikin Stainless Steel Corporation
    Inventors: Masaharu Hatano, Akihiko Takahashi
  • Patent number: 8257516
    Abstract: The present invention relates to a method of manufacturing ultra-high strength steel products and, more particularly, to a method of manufacturing ultra-high strength steel products suitable for production of articles having a complicated shape or a high processing depth. The method includes preparing a steel sheet by blanking the steel sheet having hardenability to form a rough shape of a final product, cold-pressing the steel sheet to form a 50˜80% shape of the final product, precisely trimming the cold-formed steel sheet along a contour line corresponding to an outer contour of the final product, and hot-pressing the trimmed product to form the remaining 20˜50% shape of the final product and quenching simultaneous with hot-pressing, after heating the trimmed product to an austenite region of 700° C. or more.
    Type: Grant
    Filed: May 27, 2009
    Date of Patent: September 4, 2012
    Assignee: Hyundai Hysco
    Inventors: Hee Joong Im, Seung Man Nam, Man Been Moon, Sang Muk Na, Sung Namkoong
  • Patent number: 8257517
    Abstract: A steel sheet excellent in mechanical strength, workability and thermal stability and suited for use as a raw material in such fields of manufacturing automobiles, household electric appliances and machine structures and of constructing buildings, and a manufacturing method thereof are provided. The steel sheet is a hot-rolled steel sheet of carbon steel or low-alloy steel, the main phase of which is ferrite, and is characterized in that the average ferrite crystal grain diameter D (?m) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfies the relations respectively defined by the formulas (1) and (2) given below and the increase rate X (?m/min) in average ferrite crystal grain diameter at 700° C. at the depth of ¼ of the sheet thickness from the steel sheet surface and said average crystal grain diameter D (?m) satisfy the relation defined by the formula (3) given below: 1.2?D?7??formula (1) D?2.7+5000/(5+350·C+40·Mn)2??formula (2) D·X?0.
    Type: Grant
    Filed: March 14, 2011
    Date of Patent: September 4, 2012
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Toshirou Tomida, Norio Imai, Mitsuru Yoshida, Kaori Kawano, Masayuki Wakita, Tamotsu Toki, Masanori Yasuyama, Hitomi Nishibata
  • Publication number: 20120211128
    Abstract: A steel part having a homogeneous multiphase microstructure in each region of the part, the microstructure containing ferrite, wherein the steel part is obtained by a process involving: cutting a blank from a strip of steel, having a specified composition; optionally, the blank undergoes prior cold deformation; the blank is heated to reach a soak temperature Ts above Ac1 but below Ac3 and held at this soak temperature Ts for a soak time ts adjusted so that the steel, after the blank has been heated, has an austenite content equal to or greater than 25% by area; the heated blank is transferred into a forming tool to hot-form the part; and the part is cooled within the tool at a cooling rate V such that the microstructure of the steel, after cooling the part, is a multiphase microstructure containing ferrite and being homogeneous in each region of the part.
    Type: Application
    Filed: January 5, 2012
    Publication date: August 23, 2012
    Applicant: ArcelorMittal France
    Inventors: Jacques CORQUILLET, Jacques DEVROC, Jean-Louis HOCHARD, Jean-Pierre LAURENT, Antoine MOULIN, Nathalie ROMANOWSKI
  • Patent number: 8221564
    Abstract: A method for manufacturing a steel sheet used for structural members, elements, etc. of automobiles including a front side member, pillar, and the like, and more particularly, a method for manufacturing a steel sheet having a high strength and formability as well as hot-dip galvanizing properties is disclosed. In the method, after an aluminum killed steel slab, which comprises, by weight %: C: 0.05% to 0.25%; Si: 0.1% to 1.5%; S: 0.02% or less; N: 0.01% or less; Al: 0.02% to 2.0%; Mn: 1.0% to 2.5%; P: 0.001% to 0.1%; Sb: 0.005% to 0.10%; the balance of Fe and other unavoidable impurities, is subjected to a homogenization treatment at a temperature range of 1050° C. to 1300° C., the aluminum killed steel slab is subjected to a hot rolling under a finishing hot rolling temperature of 850° C. to 950° C. and a coiling temperature of 400° C. to 700° C., followed by a cold rolling under a cold rolling reduction ration of 30% to 80%, and annealing the cold rolled steel sheet.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: July 17, 2012
    Assignee: POSCO
    Inventors: Seong-Ju Kim, Il-Ryoung Sohn, Hyun-Gyu Hwang, Seung-Bok Lee
  • Patent number: 8177929
    Abstract: A metal gasket formed from a suitable iron-nickel chromium alloy includes at least one embossment that exhibits essentially full functional recovery at temperatures exceeding 1000° F. and including in the range of 1100° F. to 1600° F. or more and which is made from sheet material that is work hardened and strengthened by cold rolling, or a combination of cold rolling and precipitation hardening, without any post embossment heat treating that would act to further harden the material. Suitable iron-nickel-chromium alloys include those comprising, by weight, greater than 18% nickel; greater than 14% chrome and 0.1-10% of at least one element selected from the group consisting of Mo, Ti, V, Al, Co, Nb, Ta and Cu, with the balance being substantially Fe, wherein the gasket sheet alloy has a deformed microstructure.
    Type: Grant
    Filed: March 18, 2010
    Date of Patent: May 15, 2012
    Assignee: Federal-Mogul World Wide, Inc.
    Inventor: Thomas Zurfluh
  • Patent number: 8137487
    Abstract: The present invention provides high strength thin-gauge steel sheet with excellent elongation and hole expandability having a tensile strength of 500 MPa or more and a method of production of high strength thin-gauge steel sheet with excellent elongation and hole expandability enabling production of this on an industrial scale, that is, high strength thin-gauge steel sheet comprised of, by mass %, C: 0.03 to 0.25%, Si: 0.013 to 0.299%, Mn: 0.8 to 3.1%, P?0.02%, S?0.02%, Al?2.0%, N?0.01%, and a balance of Fe and unavoidable impurities and having a microstructure comprised of ferrite with an area fraction of 10 to 85% and residual austenite with a volume fraction of 1 to 10%, an area fraction of 10% to 60% of tempered martensite, and a balance of bainite.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: March 20, 2012
    Assignee: Nippon Steel Corporation
    Inventors: Toshiki Nonaka, Hirokazu Taniguchi, Koichi Goto
  • Patent number: 8128762
    Abstract: Disclosed is a high-strength steel sheet which has a predetermined component composition, structurally has a ferrite matrix structure and bainitic and martensitic second phase structures, and has a ferrite fraction of from 50 to 86 percent by area, a bainite fraction of from 10 to 30 percent by area, and a martensite fraction of from 4 to 20 percent by area, relative to the entire structure, in which the bainite area fraction is larger than the martensite area fraction, the ferrite has an average grain size of 2.0 to 5.0 ?m, and the ratio of the average ferrite hardness (Hv) to the tensile strength (MPa) of the steel sheet is equal to or more than 0.25. The steel sheet excels both in TS-EL balance and TS-? balance at high strengths on the order of 590 to 780 MPa.
    Type: Grant
    Filed: July 7, 2009
    Date of Patent: March 6, 2012
    Assignee: Kobe Steel, Ltd.
    Inventor: Seiko Watanabe
  • Patent number: 8070889
    Abstract: The invention is directed to providing, for application in automobiles, construction materials, household appliances and the like, high-strength sheets excellent in formability properties such as hole expansibility and ductility, and also in fatigue resistance, characterized in comprising, in specified contents expressed in mass %, C, Si, Mn, P, S, Al, N and O and a balance of iron and unavoidable impurities, and having a steel sheet structure composed mainly of ferrite and hard structures, a crystal orientation difference between some ferrite adjacent to hard structures and the hard structures of less than 9°, and a maximum tensile strength of 540 MPa or greater.
    Type: Grant
    Filed: April 9, 2009
    Date of Patent: December 6, 2011
    Assignee: Nippon Steel Corporation
    Inventors: Masafumi Azuma, Noriyuki Suzuki, Naoki Maruyama, Naoki Yoshinaga, Akinobu Murasato
  • Patent number: 8012276
    Abstract: The invention provides a steel sheet for hard tinplate and a TFS steel sheet each having an excellent formability and a temper grade of T4 to DR9, and an efficient manufacturing method capable of selectively manufacturing these steel sheets by using raw materials having the same composition, wherein, the steel sheet for hard tinplate and a TFS steel sheet having a temper grade of T4 to DR9 is manufactured from raw materials having the same composition by changing a reduction ratio of temper rolling or double reduce rolling for ultra-low carbon aluminum killed steel C and P contents of which are so regulated as to satisfy a specific formula <1>: 1.6×C×104+0.93×P×103?70??<1>.
    Type: Grant
    Filed: October 1, 2008
    Date of Patent: September 6, 2011
    Assignee: Nippon Steel Corporation
    Inventors: Satoshi Takeuchi, Riki Okamoto, Kazuhito Ito
  • Publication number: 20110192507
    Abstract: An iron alloy according to the present invention comprises: Al in an amount of from 3 to 5.5%; Mn in an amount from 0.2 to 6%; and the balance being iron (Fe), and inevitable impurities and/or a modifying element; when the entirety is taken as 100%. Since a high damping factor is obtainable at a low-strain amplitude, this iron alloy demonstrates a stable damping property even in a high-temperature region. Moreover, since the alloying elements are Al and Mn alone, and since their contents are less, the iron alloy according to the present invention is low in cost.
    Type: Application
    Filed: September 8, 2009
    Publication date: August 11, 2011
    Applicant: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI
    Inventors: Keita Yamana, Motoharu Tanizawa, Masanori Harata, Kyoichi Kinoshita
  • Patent number: 7959747
    Abstract: A steel sheet having (a) a dual phase microstructure with a martensite phase and a ferrite phase and (b) a composition containing by percent weight: 0.01?C?0.2; 0.3?Mn?3; 0.05?Si?2; 0.2?Cr+Ni?2; 0.01?Al?0.10; 0.0005?Ca?0.01, with the balance of the composition being iron and incidental ingredients. Also, the steel sheet is made by a batch annealing method, and has a tensile strength of at least approximately 400 megapascals and an n-value of at least approximately 0.175.
    Type: Grant
    Filed: July 22, 2008
    Date of Patent: June 14, 2011
    Assignee: Nucor Corporation
    Inventor: Weiping Sun
  • Patent number: 7938917
    Abstract: A method for controlling the cooling of a steel sheet characterized by controlling the end-of-cooling temperature in a cooling process from the Ae3 or above temperature of the steel sheet, during which; preliminarily obtaining enthalpies (H? and H?) of an austenite phase and ferrite phase respectively at some temperature, obtaining a gynamic enthalpy (Hsys) defined by formula (1) with an untransformed fraction (X?) of austenite in accordance with a target temperature pattern, predicting the temperature by using a gradient of this dynamic enthalpy with respect to temperature as a dynamic specific heat and controlling the cooling of the steel sheet: Hsys=H?(X?)+H?(1?X?).
    Type: Grant
    Filed: December 8, 2005
    Date of Patent: May 10, 2011
    Assignee: Nippon Steel Corporation
    Inventors: Riki Okamoto, Noriyuki Hishinuma, Hidenori Miyata, Hirokazu Taniguchi
  • Patent number: 7922968
    Abstract: Provided are a steel sheet for an automotive muffler and a method for producing the steel sheet. The steel sheet includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.04% by weight of Co, and a remainder of Fe and unavoidable impurities. The method includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.
    Type: Grant
    Filed: October 25, 2006
    Date of Patent: April 12, 2011
    Assignee: Posco
    Inventors: Won-Ho Son, Jai-Ik Kim, Seung-Hee Lee, Jeong-Bong Yoon, Hee-Man Son
  • Patent number: 7846276
    Abstract: The present disclosure provides alloys having an ultra-low coefficient of thermal expansion in the range of 60° F. to 80° F. The alloys have coefficient of thermal expansion no greater than 0.35×10?6° F.?1 in the range of 60° F. to 80° F. Methods of making such alloys also are provided, as well articles of manufacture including such alloys and methods of making such articles.
    Type: Grant
    Filed: May 1, 2007
    Date of Patent: December 7, 2010
    Assignee: ATI Properties, Inc.
    Inventors: David R. Hasek, Thomas R. Parayil
  • Patent number: 7838075
    Abstract: A method for strengthening a surface of a metal member. The method includes the following steps in the sequence set forth: (a) coating the surface of the metal member with a carbon-based film having a thickness of not smaller than 0.2 ?m; and (b) repeatedly applying a pressing force onto the surface of the film-coated metal member in a condition of maintaining a contact pressure of not lower than 2.5 GPa at the surface of the film-coated metal member.
    Type: Grant
    Filed: July 5, 2006
    Date of Patent: November 23, 2010
    Assignee: JATCO Ltd
    Inventors: Masao Kumagai, Yoshio Jimbo, Fumiya Yakabe
  • Patent number: 7806998
    Abstract: A super formable high strength thin steel sheet suitable for use in various applications, e.g., automobiles, and a method for manufacturing the thin steel sheet. The thin steel sheet has a composition which comprises 0.010 wt % or less of C, 0.02 wt % or less of Si, 1.5 wt % or less of Mn, 0.03-0.15 wt % or less of P, 0.02 wt % or less of S, 0.03-0.40 wt % of Sol. Al, 0.004 wt % or less of N, 0.005-0.040 wt % of Ti, 0.002-0.020 wt % of Nb, one or both of 0.001-0.02 wt % of B and 0.005-0.02 wt % of Mo, and the balance of Fe and inevitable impurities, wherein the components P, Mn, Ti, Nb and B satisfy the relationship represented by the following Formulae 1-1 and 1-2, depending on a desired tensile strength: Formula 1-1—tensile strength: 35 kg and 40 kg grades 29.1+89.4P(%)+3.9Mn(%)?133.8Ti(%)+157.5Nb(%)+0.18[B(ppm) or Mo(%)] 15=3544.9 Formula 1-2—tensile strength: 45 kg grade 29.1+98.3P(%)+4.6 Mn(%)86.5Ti(%)62.5Nb(%)+0.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: October 5, 2010
    Assignee: Posco
    Inventors: Hee-Jae Kang, Sang-Ho Han
  • Publication number: 20100221572
    Abstract: The invention relates to a steel part, the composition of the steel of which comprises, the contents being expressed by weight: 0.040%?C?0.100%; 0.80%?Mn?2.00%; Si?0.30%; S?0.005%; P?0.030%; 0.010% S?Al?0.070%; 0.015%?Nb?0.100%; 0.030% Ti?0.080%; N?0.009%; Cu?0.100%; Ni?0.100%; Cr?0.100%; Mo?0.100%; and Ca?0.006%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the steel consisting of at least 75% equiaxed ferrite, martensite in an amount not less than 5% but not exceeding 20%, and bainite in an amount not exceeding 10%.
    Type: Application
    Filed: March 3, 2008
    Publication date: September 2, 2010
    Applicant: ARCELORMITTAL FRANCE
    Inventors: Jean-Pierre Laurent, Thierry Malot
  • Patent number: 7758707
    Abstract: The invention relates to a martensitic stainless steel to be used for making a razor, surgical and similar blades or other cutting tools, which steel contains 0.40 to 0.55 wt % carbon, 0.8 to 1.5 wt % silicon, 0.7 to 0.85 wt % manganese, 13.0 to 14.0 wt % chromium, 1.0 to 1.5 wt % molybdenum and 0.2 to 0.4 wt % nickel, 0.02 to 0.04 wt % nitrogen, the balance of the steel being iron and inevitable impurities. The invention also relates to a method of manufacturing the said steel.
    Type: Grant
    Filed: June 16, 2006
    Date of Patent: July 20, 2010
    Assignee: Outokumpu Oyj
    Inventor: Chris Millward
  • Patent number: 7754030
    Abstract: A high-strength steel sheet has a metal structure consisting of a ferrite phase in which a hard second phase is dispersed and has 3 to 30% of an area ratio of the hard second phase. In the ferrite phase, the area ratio of nanograins of which grain sizes are not more than 1.2 ?m is 15 to 90%, and dS as an average grain size of nanograins of which grain sizes are not more than 1.2 ?m and dL as an average grain size of micrograins of which grain sizes are more than 1.2 ?m satisfy an equation (dL/dS?3).
    Type: Grant
    Filed: November 30, 2005
    Date of Patent: July 13, 2010
    Assignee: Honda Motor Co., Ltd.
    Inventor: Yoshitaka Okitsu
  • Patent number: 7749343
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Grant
    Filed: August 4, 2008
    Date of Patent: July 6, 2010
    Assignee: Nippon Steel Corporation
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Patent number: 7722697
    Abstract: The present invention relates to a steel band 1 for the manufacturing of doctor blades, coater blades or creping blades comprising a steel composition comprising in percent per weight 1-3% C, 4-10% Cr, 1-8% Mo, 2.5-10% V and the remainder essentially iron and contaminants in normal amounts, wherein the steel band 1 is produced by using a powder metallurgical process. Further, this invention relates to doctor blades, coater blades or creping blades of this steel band, as well as a method for its manufacture.
    Type: Grant
    Filed: July 7, 2005
    Date of Patent: May 25, 2010
    Assignee: Böhler-Uddeholm Precision Strip GmbH & Co. KG
    Inventors: Manfred Daxelmüller, Helmut Ponemayr
  • Publication number: 20100108207
    Abstract: Provided is a method of manufacturing a high strength ferritic/martensitic steel. The method includes melting a ferritic/martensitic steel, hot-working the melted ferritic/martensitic steel, normalizing the hot-worked ferritic/martensitic steel at a temperature of about 1050° C. to about 1200° C., tempering the ferritic/martensitic steel at a temperature of about 600° C. or less, and leaving MX precipitates while preventing a M23C6 precipitate from being precipitated, and cold-working and thermal-treating the ferritic/martensitic steel in a multistage fashion, and precipitating M23C6 precipitates. Through the above described configuration, the high strength ferritic/martensitic steel that prevents a ductility from being deteriorated even in a high-temperature environment may be manufactured.
    Type: Application
    Filed: November 4, 2009
    Publication date: May 6, 2010
    Inventors: Woo-Gon Kim, Chan-Bock Lee, Jong-Hyuk Baek, Do-Hee Hahn, Sung-Ho Kim, Chang-Hee Han, Tae-Kyu Kim, Jun-Hwan Kim