Separate Cooling Step Follows Cold Working Step Patents (Class 148/652)
  • Patent number: 10927428
    Abstract: A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.5<Si+Al<1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n2)2/3×d2}/{(n1)2/3×d1}×ln(H2/H1)<0.3 when the n1 is the number of a MnS of a surface portion of the steel sheet, the d1 ?m is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the H1 GPa is a hardness of a martensite of the surface portion of the steel sheet, the n2 is the number of the MnS of a center portion of the steel sheet, the d2 ?m is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the H2 GPa is the hardness of the martensite of the center portion of the steel sheet.
    Type: Grant
    Filed: March 18, 2019
    Date of Patent: February 23, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Toshiki Nonaka, Toshio Ogawa, Nobuhiro Fujita
  • Patent number: 10589326
    Abstract: A method for manufacturing a linear cutter permits continuous manufacturing of linear cutters and achieving remarkable reduction in processing steps, processing time, and a process cost, and is immediately feasible to linear cutters having special lengths. The method includes the steps of: preparing a pair of roller dies for forming a die hole for processing a wire rod into a predetermined shape, the die hole having keen angle parts for forming a cutting edge; and causing the wire rod to pass through the die hole in a state that the roller dies revolve and thereby forming a sectional shape of the wire rod into a pre-set shape and, at the same time, forming a cutting edge at least at one edge of the wire rod.
    Type: Grant
    Filed: December 19, 2016
    Date of Patent: March 17, 2020
    Assignee: YAMAUCHI MATEX CORPORATION
    Inventor: Ryuji Yamauchi
  • Patent number: 10518306
    Abstract: The present disclosure relates to a method for producing a structural element. A number of upper and/or lower rollers arranged one after the other in a direction of rolling is rolled in a metal strip to produce a varying thickness in the metal strip. The method includes providing the upper and/or lower rollers of each group with shape-changing profiles in the direction of rolling. The shape-changing profile of each group in each case exhibits a constant volume. The method may further include prefabricating the metal strip with partial contours produced on the basis of the shape-changing profiles to a desired final contour. The method may also include feeding the prefabricated metal strip with the desired final contour for further processing steps.
    Type: Grant
    Filed: March 18, 2016
    Date of Patent: December 31, 2019
    Assignee: Ford Global Technologies, LLC
    Inventors: Selahattin Turel Memili, Igor Licko
  • Patent number: 10253389
    Abstract: A high-yield-ratio, high-strength cold-rolled steel sheet has a composition containing, in terms of % by mass, C: 0.13% to 0.25%, Si: 1.2% to 2.2%, Mn: 2.0% to 3.2%, P: 0.08% or less, S: 0.005% or less, Al: 0.01% to 0.08%, N: 0.008% or less, Ti: 0.055% to 0.130%, and the balance being Fe and unavoidable impurities. The steel sheet has a microstructure that contains 2% to 15% of ferrite having an average crystal grain diameter of 2 ?m or less in terms of volume fraction, 5 to 20% of retained austenite having an average crystal grain diameter of 0.3 to 2.0 ?m in terms of volume fraction, 10% or less (including 0%) of martensite having an average grain diameter of 2 ?m or less in terms of volume fraction, and the balance being bainite and tempered martensite, and the bainite and the tempered martensite having an average crystal grain diameter of 5 ?m or less.
    Type: Grant
    Filed: March 17, 2015
    Date of Patent: April 9, 2019
    Assignee: JFE Steel Corporation
    Inventors: Katsutoshi Takashima, Kohei Hasegawa
  • Patent number: 9863022
    Abstract: This H-beam steel has a composition including C, Si, Mn, Cu, Ni, V, Al, Ti, B, N, and O, and further including at least one of Mo and Nb, in which Ceq obtained in Equation 1 described below falls in a range of 0.37 to 0.50, the thickness of a flange falls in a range of 100 to 150 mm, and the area fraction of bainite at a depth of one quarter of the thickness of the flange from the external surface of the flange is 60% or more. Ceq=C+Mn/6+(Mo+V)/5+(Ni+Cu)/15??Equation 1, where C, Mn, Mo, V, Ni, and Cu represent the amount of each element contained.
    Type: Grant
    Filed: December 11, 2012
    Date of Patent: January 9, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kazutoshi Ichikawa, Masaki Mizoguchi, Kazuaki Mitsuyasu, Hirokazu Sugiyama
  • Patent number: 9534279
    Abstract: A high-strength cold-rolled steel sheet has a chemical composition including C of 0.05% to 0.30%, Si of greater than 0% to 3.0%, Mn of 0.1% to 5.0%, P of greater than 0% to 0.1%, S of greater than 0% to 0.02%, Al of 0.01% to 1.0%, and N of greater than 0% to 0.01%, in mass percent, with the remainder including iron and inevitable impurities. The steel sheet has a microstructure containing ferrite as a soft primary phase in an area percentage of 20% to 50% with the remainder including tempered martensite and/or tempered bainite as a hard secondary phase. The ferrite grains are adapted to contain cementite particles having an appropriate size in an appropriate number density.
    Type: Grant
    Filed: December 11, 2012
    Date of Patent: January 3, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Tomokazu Masuda, Hideo Hata, Katsura Kajihara, Toshio Murakami, Masaaki Miura, Muneaki Ikeda
  • Patent number: 9074272
    Abstract: A high-strength cold-rolled steel sheet excellent in uniform elongation, including in percent by mass: 0.10-0.28% of C; 1.0-2.0% of Si; and 1.0-3.0% of Mn, and the structures of the same having the space factors below to the entire structure: 30-65% of bainitic ferrite; 30-50% of polygonal ferrite; and 5-20% of residual austenite.
    Type: Grant
    Filed: March 28, 2006
    Date of Patent: July 7, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroshi Akamizu, Yoichi Mukai, Shushi Ikeda, Koichi Sugimoto
  • 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: 8951366
    Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.
    Type: Grant
    Filed: January 26, 2011
    Date of Patent: February 10, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
  • Patent number: 8911567
    Abstract: The high-strength steel sheet includes, by mass %: C: 0.01% to 0.10%; Si: 0.15% or less; Mn: 0.80% to 1.80%; P: 0.10% or less; S: 0.015% or less; Al: 0.10% to 0.80%; Cr: 0.01% to 1.50%; N: 0.0100% or less; and a balance consisting of iron and inevitable impurities, in which a metallic structure is composed of ferrite and a hard second phase, the area fraction of the ferrite is 80% or more, the area fraction of the hard second phase is 1% to 20%, the fraction of unrecrystallized ferrite in the ferrite is less than 10%, the ferrite grain sizes are 5 ?m to 20 ?m, and the fraction of the ferrite crystal grains having an aspect ratio of 1.2 or less in the entire ferrite crystal grains is 60% or more.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: December 16, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Toshio Ogawa, Naoki Matsutani, Koichi Goto, Shinichiro Watanabe, Nobuhiro Fujita, Toshiki Nonaka
  • Patent number: 8882938
    Abstract: A high strength hot dip galvanized steel strip including, in mass percent, of the following elements: 0.10-0.18% C, 1.90-2.50% Mn, 0.30-0.50% Si, 0.50-0.70% Al, 0.10-0.50% Cr, 0.001-0.10% P, 0.01-0.05% Nb, max 0.004% Ca, max 0.05% S, max 0.007% N, and optionally at least one of the following elements: 0.005-0.50% Ti, 0.005-0.50% V, 0.005-0.50% Mo, 0.005-0.50% Ni, 0.005-0.50% Cu, max 0.005% B, the balance Fe and inevitable impurities, wherein 0.80%<Al+Si<1.05% and Mn+Cr>2.10%. This steel offers improved formability at a high strength, has a good weldability and surface quality together with a good produce-ability and coat-ability.
    Type: Grant
    Filed: December 21, 2010
    Date of Patent: November 11, 2014
    Assignee: Tata Steel Ijmuiden B.V.
    Inventors: Bernard Leo Ennis, David Neal Hanlon
  • 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: 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: 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: 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: 8262818
    Abstract: A high strength steel sheet excellent in formability which has a chemical composition in mass %: C: 0.03 to 0.20%, Si: 0.005 to 0.3%, Mn: 1.0 to 3.1%, P: 0.001 to 0.06%, S: 0.001 to 0.01%, N: 0.0005 to 0.01%, Al: 0.2 to 1.2%, Mo?0.5%, and the balance: Fe and inevitable impurities, with the proviso that the values of mass % for Si and Al satisfy the following formula (1): (0.0012×[objective value of TS]?0.29?[Si])/2.45<Al<1.5?3×[Si]??(1) wherein [objective value of TS] represents a design strength value for the steel sheet in an Mpa unit, and has a metal structure containing ferrite and martensite. The above high strength steel sheet is also excellent in formability and the capability of being chemically treated and that of being hot-dip zinc sheeted.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: September 11, 2012
    Assignee: Nippon Steel Corporation
    Inventors: Toshiki Nonaka, Hirokazu Taniguchi, Masaaki Mizutani, Nobuhiro Fujita
  • 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: 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: 7976647
    Abstract: The invention concerns a very high mechanical strength steel, whereof the chemical composition comprises in wt. %: 0.006%=C=0250%; 0.400%=Mn=0.950%; Si=0.300%; Cr=0.300%; 0.100%=Mo=0.500%; 0.020%=AI=0.100%; P=0.100%; B=0.010%; Ti=0.050%, the rest being iron and impurities resulting from preparation. The invention also concerns a method for making a sheet of said steel coated with zinc or zinc alloy.
    Type: Grant
    Filed: September 4, 2003
    Date of Patent: July 12, 2011
    Assignee: USINOR
    Inventors: Antoine Moulin, Jean-Luc Lapointe
  • 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: 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: 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: 7686896
    Abstract: A high-strength steel sheet is useful for applications to automobile steel sheets and the like and has excellent deep drawability, a tensile strength (TS) of as high as 440 MPa or more, and a high r value (average r value ?1.2), and a process for producing the steel sheet. The steel sheet has a composition containing, by % by mass, 0.010 to 0.050% of C, 1.0% or less of Si, 1.0 to 3.0% of Mn, 0.005 to 0.1% of P, 0.01% or less of S, 0.005 to 0.5% of Al, 0.01% or less of N, and 0.01 to 0.3% of Nb, the Nb and C contents in steel satisfying the relation, (Nb/93)/(C/12)=0.2 to 0.7, and the balance substantially including Fe and inevitable impurities. The steel microstructure contains a ferrite phase and a martensite phase at area ratios of 50% or more and 1% or more, respectively, and the average r value is 1.2 or more.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: March 30, 2010
    Assignee: JFE Steel Corporation
    Inventors: Hiromi Yoshida, Kaneharu Okuda, Toshiaki Urabe, Yoshihiro Hosoya
  • Patent number: 7540928
    Abstract: The invention concerns a method for making hardenable steel plates by firing comprising: preparing a steel whereof the composition comprises, expressed in weight percent: 0.03=C=0.06, 0.50=Mn=1.10, 0.08:=Si=0.20, 0.015=Al=0.070, N=0.007, Ni=0.040, Cu=0.040, P=0.035, S=0.015, Mo=0.010, Ti=0.005; provided that it comprises boron in an amount such that 0.64=B/N=1.60 the rest consisting of iron and impurities resulting from production; casting a slab of said steel, then hot rolling of said slab to obtain a plate, the final rolling temperature being higher than the point Ar3; winding said plate at a temperature ranging between 500 and 700° C.; then cold rolling of said plate at a reduction rate ranging between 50 and 80%; continuous annealing heat treatment for a time interval less than 15 minutes; and strain hardening with a reduction rate ranging between 1.25 and 2.5%. The invention also concerns the hardenable plates and the parts obtainable therefrom.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: June 2, 2009
    Assignee: Usinor
    Inventors: Joël Marsal, Fernande Kirch, Dominique Mescolini
  • Patent number: 7507307
    Abstract: The present invention provides a method for manufacturing an ultra high strength cold-rolled steel sheet, comprising the step of continuously annealing a cold-rolled steel sheet consisting essentially of, in terms of weight percentages, 0.07 to 0.15% C, 0.7 to 2% Si, 1.8 to 3% Mn, 0.02% or less P, 0.01% or less S, 0.01 to 0.1% Sol. Al, 0.005% or less N, 0.0003 to 0.003% B, and the balance being Fe, in which such continuous annealing comprises the steps of: heating the cold-rolled steel sheet at from 800° C. to 870° C. for 10 seconds or more; slowly cooling the heated steel sheet down to from 650° C. to 750° C.; rapidly cooling the slowly cooled steel sheet down to 100° C. or less at a cooling speed of over 500° C./sec; reheating the rapidly cooled steel sheet at from 325° C. to 425° C. for from 5 minutes to 20 minutes; cooling the reheated steel sheet down to room temperature; and coiling the cooled steel sheet.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: March 24, 2009
    Assignee: JFE Steel Corporation
    Inventors: Kohei Hasegawa, Nobuyuki Nakamura, Toshiaki Urabe
  • Publication number: 20080308200
    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: Application
    Filed: August 4, 2008
    Publication date: December 18, 2008
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Patent number: 7459039
    Abstract: The method of making steel with carbide banding entails using steel with undissolved carbides distributed within the steel for forming steel with carbide banding, wherein the steel is about 0.3 weight percent to about 2.2 weight percent carbon and at least 0.003 weight percent of chromium, molybdenum, aluminum, vanadium, tungsten, or a similar carbide forming element; then, deforming the steel with undissolved carbides to create steel with carbide banding upon cooling, heating the steel with undissolved carbides for a specified time ranging at a specified temperature to form an austenitic steel with undissolved carbides, and cooling the austenitic steel with undissolved carbides to maintain the undissolved carbides within a crystalline matrix forming steel with carbide banding.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: December 2, 2008
    Inventor: Daniel Watson
  • Patent number: 7459038
    Abstract: The invention is method of making steel with carbide banding obtaining steel with undissolved carbides distributed within the steel for forming steel with carbide banding, wherein the steel is about 0.3 weight percent to about 2.2 weight percent carbon and at least 0.003 weight percent of chromium, molybdenum, aluminum, vanadium, tungsten, or a similar carbide forming element; then, deforming the steel with undissolved carbide, moving a portion of the steel with undissolved carbides, heating the steel with undissolved carbides for a time ranging from about 5 minutes to about 12 hours at a temperature above an A-sub 1 temperature and below 50 degrees Fahrenheit of an A-sub 3 temperature to form an austenitic steel with undissolved carbides, and cooling the austenitic steel with undissolved carbides to maintain the undissolved carbides within a crystalline matrix forming steel with carbide banding.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: December 2, 2008
    Inventor: Daniel Watson
  • Patent number: 7442268
    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% to 0.2% C; 0.3% to 3% Mn; 0.05% to 2% Si; 0.1% to 2% Cr; 0.01% to 0.10 Al; and 0.0005% to 0.01% Ca, 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 MPa and an n-value of at least approximately 0.175.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: October 28, 2008
    Assignee: Nucor Corporation
    Inventor: Weiping Sun
  • Patent number: 7413617
    Abstract: The present invention provide a TRIP-type composite structure steel plate of the TPF steel type in which elongation and stretch flange formability at room temperature are improved by controlling the morphology of the second-phase structure. In a composite structure sheet steel comprising 0.02 to 0.12% C, 0.5 to 2.0% Si+Al and 1.0 to 2.0% Mn, with the remainder being Fe and unavoidable impurities, and comprising 80% or more polygonal ferrite (steel structure space factor) and 1 to 7% retained austenite, with the remainder being bainite and/or martensite, wherein the elongation and stretch flange formability of the composite sheet steel are improved by reducing the number of bulky, massive second phases with an aspect ratio of 1:3 or less and a mean grain size of 0.5 ?m or more in the second phase of this composite structure, which comprises retained austenite and martensite.
    Type: Grant
    Filed: December 1, 2005
    Date of Patent: August 19, 2008
    Assignees: Kabushiki Kaisha Kobe Seiko Sho, Shinshu TLO Co., Ltd.
    Inventors: Shushi Ikeda, Koichi Sugimoto, Yoichi Mukai, Hiroshi Akamizu
  • Patent number: 7252724
    Abstract: A high tensile strength hot-rolled steel sheet having superior strain aging hardenability, which has high formability and stable quality characteristics, and in which satisfactory strength is obtained when the steel sheet is formed into automotive components, thus enabling the reduction in weight of automobile bodies is provided. Specifically, a method for producing a high tensile strength hot-rolled steel sheet having superior strain aging hardenability with a BH of 80 MPa or more, a ?TS of 40 MPa or more, and a tensile strength of 440 MPa or more includes the steps of heating a steel slab to 1,000° C. or more, the steel slab containing, in percent by mass 0.15% or less of C, 2.0% or less of Si, 3.0% or less of Mn, 0.08% or less of P, 0.02% or less of S, 0.02% or less of Al, 0.0050% to 0.0250% of N, and optionally 0.1% or less in total of at least one of more than 0.02% to 0.1% of Nb and more than 0.02% to 0.1% of V, the ratio N (mass %)/Al (mass %) being 0.
    Type: Grant
    Filed: August 18, 2003
    Date of Patent: August 7, 2007
    Assignee: JFE Steel Corporation
    Inventors: Akio Tosaka, Sinjiro Kaneko, Yoichi Tominaga, Noriyuki Katayama, Nobutaka Kurosawa, Kei Sakata, Osamu Furukimi
  • Patent number: 7169243
    Abstract: A process is provided for preparation of an aluminum-killed medium-carbon steel sheet containing by weight from 0.040 to 0.080% of carbon, from 0.35 to 0.50% of manganese, from 0.040 to 0.070% of aluminum, from 0.004 to 0.006% of nitrogen, the remainder being iron and the inevitable trace impurities, wherein the steel contains carbon in free state, a grain count per mm2 greater than 20000 and, in the aged condition, has a percentage elongation A % satisfying the relationship: (640-Rm)/10?A %?(700-Rm)/l1 where Rm is the maximum rupture strength.
    Type: Grant
    Filed: June 14, 2004
    Date of Patent: January 30, 2007
    Assignee: Sollac
    Inventor: Mohamed Bouzekri
  • Patent number: 7169244
    Abstract: The present invention provides a process for manufacturing a steel strip with low aluminum content, which includes: hot-rolling a steel strip which includes between 0.050 and 0.080% by weight of carbon, between 0.25 and 0.40% by weight of manganese, less than 0.020% by weight of aluminum, and between 0.010 and 0.014% by weight of nitrogen, the remainder being iron and inevitable trace impurities, to form a strip; subjecting the strip to a first cold-rolling, to form a cold-rolled strip; annealing the cold-rolled strip, to form an annealed cold-rolled strip; optionally, subjecting the annealed cold-rolled strip to a secondary cold-rolling; wherein the annealing is a continuous annealing which includes: raising the temperature of the strip to a temperature higher than the temperature of onset of pearlitic transformation Ac1, holding the strip above this temperature for a duration of longer than 10 seconds, and rapidly cooling the strip to a temperature below 350° C. at a cooling rate in excess of 100° C.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: January 30, 2007
    Assignee: Sollac
    Inventor: Mohamed Bouzekri
  • Patent number: 7090731
    Abstract: A high strength steel sheet having (2-1) a base phase structure, the base phase structure being tempered martensite or tempered bainite and accounting for 50% or more in terms of a space factor relative to the whole structure, or the base phase structure comprising tempered martensite or tempered bainite which accounts for 15% or more in terms of a space factor relative to the whole structure and further comprising ferrite, the tempered martensite or the tempered bainite having a hardness which satisfies the relation of Vickers hardness (Hv)?500[C]+30[Si]+3[Mn]+50 where [ ] represents the content (mass %) of each element, and (2-2) a second phase structure comprising retained austenite which accounts for 3 to 30% in terms of a space factor relative to the whole structure and optionally further comprising bainite and/or martensite, the retained austenite having a C concentration (C?R) of 0.8% or more.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: August 15, 2006
    Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takahiro Kashima, Shunichi Hashimoto, Shushi Ikeda, Hiroshi Akamizu, Koh-ichi Sugimoto, Akihiko Nagasaka, Akinobu Kanda, Ryo Kikuchi
  • Patent number: 7067023
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N, 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.01% or less of S, the balance substantially composed of Fe, in which the following equations (1) and (2) are satisfied: N%?0.0015+14/93.Nb%+14/27.Al%+14/11.B%??(1) C%?(12/93).
    Type: Grant
    Filed: September 4, 2003
    Date of Patent: June 27, 2006
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Patent number: 6902632
    Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: June 7, 2005
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka, Kazunori Osawa, Shinjiro Kaneko, Takuya Yamazaki, Kaneharu Okuda, Takashi Ishikawa
  • Patent number: 6899771
    Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: May 31, 2005
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka, Kazunori Osawa, Shinjiro Kaneko, Takuya Yamazaki, Kaneharu Okuda, Takashi Ishikawa
  • Patent number: 6858099
    Abstract: A method for producing a steel material having a high fatigue strength and given a uniform residual stress by a rapid treatment. A marageing steel is subjected to a cold plastic working to have a predetermined dimension, to a solution treatment for 60 minutes or more at a temperature of 750 to 800° C., and to an aging.
    Type: Grant
    Filed: April 4, 2002
    Date of Patent: February 22, 2005
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Kazuo Ishii, Yoshinari Okada
  • Patent number: 6849139
    Abstract: The invention includes a method of forming a sputtering target containing copper of a purity of at least about 99.999 wt. %, and at least one component selected from the group consisting of Ag, Sn, Te, In, B, Bi, Sb, and P dispersed within the copper. The total of Ag, Sn, Te, In, B, Bi, Sb, and P within the copper is from at least 0.3 ppm to about 10 ppm. The sputtering target has a substantially uniform grain size of less than or equal to about 50 micrometers throughout the copper and the at least one component.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: February 1, 2005
    Assignee: Honeywell International Inc.
    Inventors: Janine K. Kardokus, Chi tse Wu, Christopher L. Parfeniuk, Jane E. Buehler
  • Publication number: 20040261920
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.
    Type: Application
    Filed: September 4, 2003
    Publication date: December 30, 2004
    Applicant: Kawasaki Steel Corporation, a corporation of Japan
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Publication number: 20040238082
    Abstract: The present invention provides a high strength cold-rolled steel sheet, consisting essentially of, by mass %, 0.04 to 0.10% C, 0.5 to 1.5% Si, 1.8 to 3% Mn, 0.02% or less P, 0.01% or less S, 0.01 to 0.1% Sol. Al, 0.005% or less N, and the balance being iron and inevitable impurities, and having a structure which substantially comprises ferrite phase and martensite phase. Since the high strength cold-rolled steel sheet of the invention has ductility in which an elongation is 18% or more, excellent stretch-flangeability in which a hole-expanding ratio is 60% or more and a tensile strength of 780 MPa or more, it is favorable for use in a structural member of automobile.
    Type: Application
    Filed: March 29, 2004
    Publication date: December 2, 2004
    Applicant: JFE STEEL CORPORATION
    Inventors: Kohei Hasegawa, Hiroshi Matsuda, Fusato Kitano, Kenji Kawamura, Hideyuki Tsurumaru
  • Publication number: 20040221928
    Abstract: A process is provided for preparation of an aluminum-killed medium-carbon steel sheet containing by weight from 0.040 to 0.080% of carbon, from 0.35 to 0.50% of manganese, from 0.040 to 0.070% of aluminum, from 0.004 to 0.
    Type: Application
    Filed: June 14, 2004
    Publication date: November 11, 2004
    Applicant: SOLLAC
    Inventor: Mohamed Bouzekri
  • Patent number: 6743307
    Abstract: The invention relates to a higher-strength steel strip or steel sheet comprising a predominantly ferritic-martensitic microstructure with a martensite content of between 4 and 20%, wherein the steel strip or steel sheet, apart from Fe and impurities due to smelting, comprises (in % by weight) 0.05-0.2% C, ≦1.0% Si, 0.8-2.0% Mn, ≦0.1% P, ≦0.015% S, 0.02-0.4% Al, ≦0.005% N, 0.25-1.0% Cr, 0.002-0.01% B. Preferably the martensite content is approximately 5% to 20% of the predominantly martensitic-ferritic microstructure. Such a higher-strength steel strip or steel sheet made from a dual phase steel comprises good mechanical/technological properties even after being subjected to an annealing process which includes an overageing treatment. Furthermore, the invention relates to a method for producing steel strip or steel sheet according to the invention.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: June 1, 2004
    Assignee: Thyssen Krupp Stahl AG
    Inventors: Bernhard Engl, Thomas Gerber, Klaus Horn
  • Patent number: 6702904
    Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: March 9, 2004
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka, Kazunori Osawa, Shinjiro Kaneko, Takuya Yamazaki, Kaneharu Okuda, Takashi Ishikawa
  • Patent number: 6695933
    Abstract: An ultra-high strength cold rolled steel sheet having a tensile strength of 880 to 1170 MPa, that consists essentially of 0.01 to 0.07% C, 0.3% or less Si, 0.1% or less P, 0.01% or less S, 0.01 to 0.1% sol.Al, 0.0050% or less N, 1.6 to 2.5% of the sum of at least one element selected from the group consisting of Mn, Cr, and Mo, by mass, and a balance of Fe, and that has an inner zone deeper than 10 &mgr;m from the surface of the steel sheet being substantially a martensitic single phase structure. Since the steel sheet has a hole expansion ratio of 75% or more, specified by the Standard of Japan Iron and Steel Federation, JFST1001-1996, the steel sheet has a tensile strength in a range of from 880 to 1170 MPa, and an excellent mechanically joining property, and is suitable for fabricating automobile seat frames.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: February 24, 2004
    Assignee: NKK Corporation
    Inventors: Kohei Hasegawa, Toshiaki Urabe, Akihide Yoshitake, Hideyuki Tsurumaru
  • Patent number: 6692584
    Abstract: The present invention provides a high tensile cold-rolled steel sheet having superior ductility, strain age-hardening characteristics, and crash resistance properties, and also provides a manufacturing method therefor. As a particular means, a thin cold-rolled steel sheet containing 0.05% to 0.30% of C, 0.4% to 2.0% of Si, 0.7% to 3.0% of Mn, 0.08% or less of P, 0.02% or less of Al, and 0.0050% to 0.0250% of N on a mass % basis is manufactured in which N/Al is 0.3 or more. This thin cold-rolled steel sheet is heated to a temperature between (an Ac1 transformation point) and (an Ac3 transformation point+50° C.), is cooled at a cooling rate of 5 to 150° C./second in the range of at least 600 to 500° C., and is held in the temperature range of 350 to 500° C. This steel sheet has superior ductility, strain age-hardening characteristics having a &Dgr;TS of 50 MPa or more, and crash resistance properties.
    Type: Grant
    Filed: December 12, 2001
    Date of Patent: February 17, 2004
    Assignee: JFE Steel Corporation
    Inventors: Kei Sakata, Akio Tosaka, Osamu Furukimi
  • Patent number: 6673170
    Abstract: Aluminum-killed medium carbon steel sheets, and the steel sheet stock prepared from it, is useful for manufacturing containers for a variety of food and industrial purposes. High mechanical strength is imparted to steel sheeting when the sheeting is processed through a continuous series of operations including cold-rolling and annealing. Annealing at a temperature maintained above the pearlitic transformation (Ac1) and rapid cooling yields steel sheet of high maximum rupture strength. Improved mechanical properties allows the steel sheet to be used in the manufacture of thin wall containers or containers of novel shape.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: January 6, 2004
    Assignee: Sollac
    Inventor: Mohamed Bouzekri
  • Patent number: 6638371
    Abstract: A cold-rolled steel sheet having an ultrafine grain structure including a ferrite phase provided. The cold-rolled steel sheet contains C, Si, Mn, Ni, Ti, Nb, Al, P, S, N and Fe and incidental impurities. The ferrite phase has a content of 65 percent by volume or more and an average grain size of 3.5 &mgr;m or less.
    Type: Grant
    Filed: March 18, 2003
    Date of Patent: October 28, 2003
    Assignee: Kawasaki Steel Corporation
    Inventors: Tetsuo Mochida, Kazuhiro Seto, Kei Sakata, Tomohisa Oonishi