Molybdenum Containing Patents (Class 148/334)
  • Patent number: 7503984
    Abstract: The present invention provides a high-strength thin steel sheet drawable and excellent in a shape fixation property and a method of producing the same. For the steel sheet, on a plane at the center of the thickness of a steel sheet, the average ratio of the X-ray strength in the orientation component group of {100}<011> to {223}<110> to random X-ray diffraction strength is 2 or more and the average ratio of the X-ray strength in three orientation components of {554}<225>, {111}<112> and {111}<110> to random X-ray diffraction strength is 4 or less. The arithmetic average of the roughness Ra of at least one of the surfaces is 1 to 3.5 ?m; the surfaces of the steel sheet are covered with a composition having a lubricating effect; and the friction coefficient of the steel sheet surfaces at 0 to 200° C. is 0.05 to 0.2.
    Type: Grant
    Filed: October 4, 2002
    Date of Patent: March 17, 2009
    Assignee: Nippon Steel Corporation
    Inventors: Tatsuo Yokoi, Teruki Hayashida, Natsuko Sugiura, Takaaki Nakamura, Takehiro Nakamoto
  • Publication number: 20090050243
    Abstract: A high-strength hot-rolled steel sheet containing C: 0.05 to 0.15%, Si: no more than 1.50% (excluding 0%), Mn: 0.5 to 2.5%, P: no more than 0.035% (excluding 0%), S: no more than 0.01% (including 0%), Al: 0.02 to 0.15%, and Ti: to 0.2%, which is characterized in that its metallographic structure is composed of 60 to 95 vol % of bainite and solid solution-hardened or precipitation-hardened ferrite (or ferrite and martensite) and its fracture appearance transition temperature (vTrs) is no higher than 0° C. as obtained by impact tests.
    Type: Application
    Filed: March 22, 2006
    Publication date: February 26, 2009
    Applicant: Kabushiki Kaisha Kobe Seiko Sho(Kobe Steel Ltd.)
    Inventors: Motoo Satou, Tetsuo Soshiroda
  • Patent number: 7485194
    Abstract: This disclosure proposes a high-strength hot rolled steel sheet having excellent anti-die-galling property and anti-fatigue property, in which the steel sheet has a composition including C: not less than 0.02 mass % but not more than 0.2 mass %, Si: not less than 0.2 mass % but not more than 1.2 mass %, Mn: not less than 1.0 mass % but not more than 3.0 mass %, Mo: not less than 0.1 mass % but not more than 1.0 mass %, Al: not less than 0.01 mass % but not more than 0.1 mass %, P: not more than 0.03 mass % S: not more than 0.01 mass % and the remainder being substantially Fe and inevitable impurities, and has a steel microstructure containing not less than 55 vol % of ferrite and not less than 10 vol % but not more than 40 vol % of martensite provided that a total of both is not less than 95 vol %, and a ratio ds/dc of an average crystal grain size ds of the ferrite in a surface layer portion of the steel sheet to an average crystal grain size dc of the ferrite in a center portion of the steel sheet is 0.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: February 3, 2009
    Assignee: JFE Steel Corporation
    Inventors: Tetsuya Mega, Kei Sakata
  • Patent number: 7485195
    Abstract: A high-strength hot-rolled steel sheet excellent in shape fixability having ferrite or bainite as the phase of the largest volume percentage, satisfying all of the following at least at ½ sheet thickness: a mean value of X-ray random intensity ratio in the orientation component group of {100}<011> to {223}<110> to X-ray random diffraction intensity ratio of at least 2.5; a mean value of X-ray random intensity ratio in the three crystal orientation components of {554}<225>, {111}<112>, and {111}<110> to X-ray random diffraction intensity ratio of 3.5 or less; an X-ray intensity ratio to X-ray random diffraction intensity ratio at {100}<011> of at least the X-ray random intensity to X-ray random diffraction intensity ratio at {211}<011>; and an X-ray random intensity ratio to X-ray random intensity ratio diffraction intensity ratio at {100}<011> of at least 2.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: February 3, 2009
    Assignees: Nippon Steel Corporation, Arcelor France
    Inventors: Natsuko Sugiura, Manabu Takahashi, Naoki Yoshinaga, Ken Kimura
  • Publication number: 20090025832
    Abstract: Disclosed herein is a spring wire rod excelling in fatigue characteristics. It contains TiN inclusions having a specific size defined by the ratio of each group in all the visual fields as follows: (1) Visual fields in which the maximum thickness is no larger than 5 ?m: less than 5% (2) Visual fields in which the maximum thickness is larger than 5 ?m and no larger than 10 ?m: no more than 30% (3) Visual fields in which the maximum thickness is larger than 10 ?m and no larger than 25 ?m: no less than 70% (4) Visual fields in which the maximum thickness is larger than 25 ?m: less than 5% The visual field is the cross section passing through the center line of the wire rod.
    Type: Application
    Filed: June 26, 2008
    Publication date: January 29, 2009
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd)
    Inventor: Nao Yoshihara
  • Publication number: 20090025831
    Abstract: Disclosed is a hot-dip galvanized steel sheet, in which a steel sheet of the hot-dip galvanized steel sheet before galvanization contains, on the percent by mass basis, 0.06% to 0.15% carbon (C); 1% to 3% manganese (Mn); 0.01% to 0.05% phosphorus (P); 0.03% to 1% chromium (Cr); 0.03% to 1% molybdenum (Mo); and 0.02% to 0.15% aluminum (Al). The steel sheet before galvanization has a silicon (Si) content of 0.2% or less (inclusive of 0%) and a sulfur (S) content of 0.03% or less (inclusive of 0%) and has a K value of ?2.0 or more, in which the K value is calculated according to following Equation (1): K value=3×[Mo]?5×[Cr]??(1) wherein “[Element]” represents the content (percent by mass) of the element.
    Type: Application
    Filed: March 24, 2006
    Publication date: January 29, 2009
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd.)
    Inventors: Katsuhiro Yamamoto, Masaaki Miura, Yukihiro Utsumi
  • Patent number: 7481897
    Abstract: An apparatus includes a low-carbon steel member. The low-carbon steel member yields plastically more than about 5% before fracturing at temperatures down to about ?40° C. when stress is applied to the low-carbon steel member sufficient to cause the low-carbon steel member to so yield.
    Type: Grant
    Filed: November 5, 2004
    Date of Patent: January 27, 2009
    Assignees: TRW Automotive U.S. LLC, Sumitomo Metal Industries Ltd.
    Inventor: Eric C. Erike
  • Publication number: 20090014098
    Abstract: There is provided a high-strength hot-dip galvanized steel sheet having excellent formability, the steel sheet eliminating special pre-structure control and capable of being produced by using a hot-dip galvanized steel-sheet production line that is not capable of sufficiently ensuring an austempering time after annealing. A high-strength hot-dip galvanized steel sheet includes, on the basis of mass percent, 0.05-0.3% C, 1.4% or less (including 0%) Si, 0.08%-3% Mn, 0.003-0.1% P, 0.07% or less S, 0.1-2.5% Al, 0.1-0.5% Cr, and 0.007% or less N, Si+Al?0.5%, and the balance being Fe and incidental impurities, wherein the steel sheet has a retained austenite content of 3% or more by volume fraction, and wherein the average aspect ratio of retained austenite grains is 2.5 or less.
    Type: Application
    Filed: April 6, 2006
    Publication date: January 15, 2009
    Applicant: JFE Steel Corporation
    Inventors: Hiroshi Matsuda, Tatsuya Nakagaito, Takayuki Futatsuka, Shusaku Takagi, Yasunobu Nagataki
  • Publication number: 20090010795
    Abstract: The invention relates to a cold-working steel having a chemical composition, in % by weight, of 1.3-2.4 (C+N), whereof at least 0.5 C, 0.1-1.5 Si, 0.1-1.5 Mn, 4.0-5.5 Cr, 1.5-3.6 (Mo+W/2), but max 0.5 W, 4.8-6.3 (V+Nb/2), but max 2 Nb, and max 0.3 S, in which the content of (C+N) and of (V+Nb/2) are balanced in relation to each other such that the contents of these elements are within an area that is defined by the coordinates A, B, C, D, A in the system of coordinates in FIG. 11, where the coordinates of [(C+N), (V+Nb/2)] for these points are A: [1.38, 4.8], B: [1.78, 4.8], C: [2.32, 6.3], D: [1.92, 6.3], and a balance essentially only iron and impurities at normal contents.
    Type: Application
    Filed: April 12, 2007
    Publication date: January 8, 2009
    Applicant: Uddeholm Tooling Aktiebolag
    Inventors: Magnus Tidesten, Lennart Jonson, Odd Sandberg
  • Publication number: 20090007998
    Abstract: A hot-rolled wire rod excelling in wire drawability is provided, in which breakage can be suppressed even in heavy work from a large diameter. A hot-rolled wire rod contains C: 0.35 to 0.65% (percent by mass, hereinafter expressed as well), Si: 1.4 to 3.0%, Mn: 0.10 to 1.0%, Cr: 0.1 to 2.0%, P: 0.025% or less (exclusive of 0%), S: 0.025% or less (exclusive of 0%), N: 0.006% or less (exclusive of 0%), Al: 0.1% or less (exclusive of 0%), and O: 0.0030% or less (exclusive of 0%), with the remnant consisting of Fe and inevitable impurities; wherein the content of hydrogen in steel is 2.50 ppm (ppm by mass, hereinafter expressed as well) or less, and hardness (HV) is 460×C00.1 or less (C0 indicates the content of C (percent by mass) in a position of depth of D/4 (D: diameter of the wire rod)).
    Type: Application
    Filed: November 7, 2006
    Publication date: January 8, 2009
    Applicant: KAB KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Takuya Kochi, Shogo Murakami, Shoji Miyazaki, Ken Ishida, Masao Toyama, Fujio Koizumi
  • Publication number: 20080302450
    Abstract: The invention discloses an object comprising at least one part made of steel, the composition of which comprises, the contents being expressed by weight, carbon with a content of between 0.005 and 0.27%, manganese between 0.5 and 1.6%, silicon between 0.1 and 0.4%, chromium in a content of less than 2.5%, Mo in a content of less than 1%, optionally one or more elements chosen from nickel, copper, aluminum, niobium, vanadium, titanium, boron, zirconium and nitrogen, the balance being iron and impurities resulting from the smelting, said steel part including at least one zone welded by a high-energy-density beam, characterized in that said welded zone has a microstructure consisting of 60 to 75% self-tempered martensite and, to complement this, 40 to 25% lower bainite, and preferably 60 to 70% self-tempered martensite and, to complement this, 40 to 30% lower bainite.
    Type: Application
    Filed: June 21, 2005
    Publication date: December 11, 2008
    Applicant: ARCELOR France
    Inventor: Dominique Kaplan
  • Publication number: 20080295920
    Abstract: The present invention provides a high tension steel plate of a tensile strength of 570 MPa or more with a small acoustic anisotropy and with excellent weldability tensile strength and a method of production of steel plate predicated on the high productivity accelerated cooling stop process, which steel sheet is a high tension steel plate with a value of 0.045%?Nb+2Ti?0.105%, A=(Nb+2Ti)×(C+N×12/14) satisfying 0.0025 to 0.0055 and with a steel composition containing bainite in an amount of 30 vol % or more and pearlite+martensite-austenite constituent (MA) in an amount of less than 5 vol %. The steel is heated to 1200° C. or more, rough rolled at 1020° C. or more, then rolled at a cumulative reduction rate from over 920° C. to less than 1020° C. of 15% or less and a cumulative reduction rate from 860 to 920° C. of 20 to 50%, then starting accelerated cooling giving a cooling rate of 2 to 30° C./sec at 800° C. or more, stopping the accelerated cooling at 600 to 700° C., then cooling by 0.4° C./sec or less.
    Type: Application
    Filed: February 14, 2005
    Publication date: December 4, 2008
    Inventors: Tatsuya Kumagai, Masaaki Fujioka
  • Patent number: 7459033
    Abstract: The present invention provides a method of production of oil country tubular goods having a small drop in collapse pressure after expansion and having a collapse pressure recovering by low temperature ageing at about 100° C. and oil country tubular goods obtained by this method of production. This method of production comprises hot rolling a steel slab having amounts of addition of C, Mn, P, S, Nb, Ti, Al, and N in specific ranges and having a balance of iron and unavoidable impurities and shaping the steel strip coiled at a temperature of not more than 300° C. as it is into a tube. Alternatively, it comprises heating steel pipe having amounts of addition of C, Mn, P, S, Nb, Ti, Al, and N in specific ranges and having a balance of iron and unavoidable impurities to a temperature of the Ac3 [° C.] to 1150° C., then cooling it in a range of 400 to 800° C. at a rate of 5 to 50° C./second.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: December 2, 2008
    Assignee: Nippon Steel Corporation
    Inventors: Hitoshi Asahi, Eiji Tsuru
  • Publication number: 20080289726
    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: Application
    Filed: July 28, 2008
    Publication date: November 27, 2008
    Applicant: NUCOR CORPORATION
    Inventor: Weiping Sun
  • Patent number: 7445750
    Abstract: The invention relates to a tool steel, the composition of which comprises (the percentages being expressed in % by weight): 0.8 ? C ? 1.5 5.0 ? Cr ? 14 0.2 ? Mn ? 3 Ni ? 5 V ? 1 Nb ? 0.1 Si + Al ? 2 Cu ? 1 S ? 0.3 Ca ? 0.1 Se ? 0.1 Te ? 0.1 1.0 ? Mo + ½W ? 4 0.06 ? Ti + ½Zr ? 0.15 0.004 ? N ? 0.02 the balance of the composition consisting of iron and impurities resulting from the smelting, it being furthermore understood that: 2.5×10?4%2?(Ti+½Zr)×N, to a process for manufacturing parts made in this steel and to the parts obtained.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: November 4, 2008
    Assignee: USINOR
    Inventors: Jean Beguinot, Dominique Viale
  • Publication number: 20080264526
    Abstract: The invention provides a hot-working die steel for die-casting obtainable by quenching a steel comprising, in terms of % by mass, C: 0.1 to 0.3%, Si: 0.1 to 1.5%, Mn: 0.3 to 2%, Cr: 6 to 12%, P: 0.05% or less, S: 0.01% or less, Mo: 1 to 3%, V: 0.5 to 1.5%, s-Al: 0.005 to 0.025%, N: 0.005 to 0.025%, and O: 0.005% or less, with the remainder being Fe and inevitable impurities, followed by tempering the steel at a temperature of 500° C. or lower.
    Type: Application
    Filed: April 27, 2007
    Publication date: October 30, 2008
    Applicant: DAIDO TOKUSHUKO KABUSHIKI KAISHA
    Inventor: Koichiro Inoue
  • Patent number: 7442264
    Abstract: The use is described, in the fabrication of apparatus and equipment used in refining and in petrochemicals (for example furnace, reactor or line elements), of a steel composition comprising: at most 0.25% C; more than 1% up to 10% Mn; 1.5% to 5% Si; at most 0.03% P; at most 0.03% S; 4% to 10% Cr; 0.5% to 2% Mo; at most 0.40% V; and at most 0.10% N; the complement to 100% being essentially iron. Steels comprising: at most 0.15% C; more than 2% up to 10% Mn; 1.5% to 5% Si; at most 0.03% P; at most 0.03% S; 4% to 10% Cr; more than 0.5% up to 2% Mo; at most 0.40% V; and at most 0.10% N; the complement to 100% being essentially iron; are themselves novel.
    Type: Grant
    Filed: February 27, 2004
    Date of Patent: October 28, 2008
    Assignee: Institute Francais du Petrole
    Inventors: Francois Ropital, Xavier Longaygue
  • Patent number: 7438771
    Abstract: A steel material for a high strength constant velocity joint intermediate shaft is provided. The steal material may preferably contain C: 0.46 to 0.52%, Si: 0.6 to 0.8%, Mn: 0.7 to 0.9%, S: 0.01 to 0.05%, Mo: 0.3 to 0.5%, B: 0.0005 to 0.005%, Al: 0.002 to 0.05%, and Ti: 0.02 to 0.09%, restricting N to 0.007% or less, Cr to 0.15% or less, and P to 0.02% or less. A structural percentage of bainite+martensite may be provided which is 40% or more. The steal material may have a hardness of 250 HV to 340 HV. A high strength constant velocity joint intermediate shaft made of that steel material may be provided which has a spline-vanishing part with a surface hardness of about 610 HV to 750 HV, and a ratio t/r of an effective hardened layer depth t and radius r of 0.35 to 0.55, having a flat part with a surface hardness of about 630 HV to 770 HV and a ratio t/r of 0.55 to 1.0, and having a core hardness of about 250 HV to 340 HV.
    Type: Grant
    Filed: October 13, 2005
    Date of Patent: October 21, 2008
    Assignees: Nippon Steel Corporation, Toyoda Koki Kabushiki Kaisha
    Inventors: Takashige Nagato, Tatsuro Ochi, Koji Nishi, Yuji Inagaki, Kazuyuki Ichikawa, Isashi Kashiwagi, Toshiyuki Saito
  • Patent number: 7438770
    Abstract: The present invention provides a high strength steel used for spring steel that has excellent hydrogen embrittlement resistance. The high strength steel which spring steel having excellent hydrogen embrittlement resistance comprises 0.20 to 0.60% of C, 1.0 to 3.0% of Si, 1.0 to 3.5% of Mn, higher than 0% and not higher than 1.5% of Al, 0.15% or less P, 0.02% or less S, and balance of iron and inevitable impurities and the structure includes: 1% or more residual austenite; 80% or more in total of bainitic ferrite and martensite; and 10% or less (may be 0%) in total content of ferrite and pearlite in the proportion of area to the entire structure, and also the mean axis ratio (major axis/minor axis) of the residual austenite grains is 5 or higher and the steel tensile strength is 1860 MPa or higher.
    Type: Grant
    Filed: January 27, 2006
    Date of Patent: October 21, 2008
    Assignees: Kobe Steel, Ltd., Shinshu TLO Co., Ltd.
    Inventors: Fumio Yuse, Kenji Saito, Shushi Ikeda, Koichi Sugimoto
  • Publication number: 20080251161
    Abstract: A high-strength cold-rolled steel sheet exhibiting an excellent strength-workability balance, including in percent by mass: 0.10-0.25% of C; 1.0-2.0% of Si; 1.5-3.0% of Mn; 0.01% or less (not including 0%) of P; 0.005% or less (not including 0%) of S; 0.01-3.0% of Al; and remaining part consisting of iron and inevitable impurities, wherein the space factor of bainitic ferrite to the entire structure is 70% or more, the space factor of residual austenite to the entire structure is 5-20%, the hardness (HV) is 270 or greater, and the half-value width of an X-ray diffraction peak on a (200)-surface of ?-iron is 0.220 degrees or smaller.
    Type: Application
    Filed: March 29, 2006
    Publication date: October 16, 2008
    Applicants: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), Shinshu TLO Co., Ltd.
    Inventors: Takahiro Kashima, Yoichi Mukai, Hiroshi Akamizu, Koichi Sugimoto
  • Patent number: 7429301
    Abstract: Disclosed herein is an ultra clean spring steel which contains inclusions easily elongated and broken into fine particles by hot rolling and which is easily adaptive to cold rolling and yields springs excelling in fatigue characteristics. The spring steel is characterized in that the wire contains oxide inclusions with a sulfur concentration no more than 10 mass % such that no less than 70% (in terms of numbers) of such inclusions, which exist in the outer layer outside one quarter of the diameter of the wire and have a width no smaller than 3 ?m, satisfies the formula (1) below, CaO+Al2O3+SiO2+MnO+MgO>80 (mass %) .
    Type: Grant
    Filed: November 23, 2005
    Date of Patent: September 30, 2008
    Assignee: Kobe Steel, Ltd.
    Inventors: Tomoko Sugimura, Koichi Sakamoto, Atsuhiko Yoshida, Sumie Suda
  • Publication number: 20080216928
    Abstract: A seamless steel pipe for line pipe having high strength and stable toughness and having resistance to sulfide corrosion cracking at low temperatures to room temperature is provided. A seamless steel pipe according to the present invention has a chemical composition comprising, in mass percent, C: 0.03-0.08%, Si: 0.05-0.5%, Mn: 1.0-3.0%, Mo: greater than 0.4% to 1.2%, Al: 0.005-0.100%, Ca: 0.001-0.005%, a remainder of Fe and impurities including N, P, S, O, and Cu, with the impurities containing at most 0.01% of N, at most 0.05% of P, at most 0.01% of S, at most 0.01% of O, and at most 0.1% of Cu, and having a microstructure comprising a bainitic-martensitic dual phase structure.
    Type: Application
    Filed: February 21, 2008
    Publication date: September 11, 2008
    Inventors: Kenji Kobayashi, Tomohiko Omura, Kunio Kondo, Yuji Arai, Nobuyuki Hisamune
  • Patent number: 7422643
    Abstract: There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300° C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: September 9, 2008
    Assignee: Komatsu Ltd.
    Inventors: Takemori Takayama, Masanari Furumoto, Chikara Nakao, Noriko Morioka
  • Patent number: 7416617
    Abstract: A high strength seamless steel pipe having mgh yield stress and excellent hydrogen-induced cracking resistance, comprises by mass %, C: 0.03-0.11%, Si: 0.05-0.5%, Mn: 0.8-1.6%, p: 0.025% or less, S: 0.003% or less, Ti: 0.002-0.017%, Al: 0.001-0.10%, Cr: 0.05-0.5%, Mo: 0.02-0.3%, V: 0.02-0.20%, Ca 0.0005-0.005%, N: 0.008% or less and O (Oxygen): 0.004% or less, the balance Fe and impurities. The steel microstructure is bainite and/or martensite and ferrite is precipitated at grain boundaries. The seamless steel pipe can contain at least one of Cu: 0.05-0.5% and Ni: 0.05-0.5%. To produce the pipe, it is desirable to limit a starting temperature of quenching after rolling, a cooling rate and a tempering temperature.
    Type: Grant
    Filed: March 25, 2005
    Date of Patent: August 26, 2008
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Nobutoshi Murao, Nobuyuki Hisamune, Hajime Osako, Kunio Kondo
  • Patent number: 7416615
    Abstract: The invention relates to a high-resistant, low-density hot laminated sheet steel comprising the following elements expressed in weight per cent: 0.04%:9 carbon?0.5%; 0.05%?manganese?3%, being able to contain hardening elements: 0.01%?niobium?0.1 0.01%?titanium?0.2% 0.01?vanadium?0.2%, either individually or combined, and/or elements acting on the transformation temperatures, 0.0005%?boron?0.005%; 0.05%?nickel?2%; 0.05%?chrome?2%; 0.05%?molybdenum?2%, either individually or combined, the remainder being iron and elements which are inherent to production, characterized in that it comprises: 2%?silicon?10%; 1%?aluminium?10%. The invention also relates to the production thereof.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: August 26, 2008
    Assignee: USINOR
    Inventors: Xavier Bano, Christian Giraud
  • Patent number: 7402215
    Abstract: Deformed wire for a submarine optical fiber cable used for the pressure-proof layer of the submarine optical cable and having a high strength, that is, having a tensile strength of 1800 MPa or more, is provided, which deformed wire for reinforcing submarine optical fiber cable is characterized by including, by wt %, C: more than 0.65% to 1.1%, Ceq=C+1/4Si+1/5Mn+4/13Cr satisfying 0.80%?Ceq?1.80%, having a number of shear bands cutting across an L-section center axial line of 20/mm per unit length of the center axis, having an angle formed by the center axis and shear bands in the range of 10 to 90°, having a tensile strength of 1800 MPa or more, having a sectional area forming an approximately fan shape, a plurality of the approximately fan shapes being combined to form a circular hollow cross-section for accommodating optical fibers, having at its surface a pebbled surface comprised of relief shapes of depths of 0.2 to 5 ?m, and having a weld at least at one location in the longitudinal direction.
    Type: Grant
    Filed: January 14, 2003
    Date of Patent: July 22, 2008
    Assignees: Nippon Steel Corporation, Namitei Co., Ltd., OCC Corporation
    Inventors: Shoichi Ohashi, Hitoshi Demachi, Masatsugu Murao, Michiyasu Honda
  • Publication number: 20080163961
    Abstract: A galvannealed steel sheet contains, by % by mass, about 0.05 to about 0.25% of C, about 2.0% or less of Si, about 1 to about 3% of Mn, about 0.1% or less of P, about 0.01% or less of S, about 0.3 to about 2% of Al, less than about 0.005% of N, about 1% or less of Cr, about 1% or less of V, about 1% or less of Mo, less than about 0.005% of Ti, and less than about 0.005% of Nb, and satisfies the relations, Si +Al >0.6% and Cr +V +Mo =0.1 to 2%, the balance being Fe and inevitable impurities.
    Type: Application
    Filed: March 31, 2006
    Publication date: July 10, 2008
    Inventors: Tatsuya Nakagaito, Takayuki Futatsuka, Hiroshi Matsuda, Yutaka Awajiya, Yasunobu Nagataki
  • Patent number: 7396422
    Abstract: The invention relates to a rolling bearing which provides superior noiselessness and high corrosion resistance and longer life, and is manufactured at a low cost, a material for the rolling bearing, and an instrument including a rotating portion using the rolling bearing. A plurality of rolling elements are provided between an inner ring and an outer ring. At least one of the inner and outer rings and is formed of corrosion resistant bearing steel comprising a specific chemical component. The corrosion resistant bearing steel comprises eutectic carbides having an average value of circle equivalent diameter of 0.2 to 1.6 ?m, an average area of 0.03 to 2 ?m2, and an area ratio of 2 to 7%. The hardness of the corrision resistant bearing steel is HRC 58 to 62 by JIS. The amount of retained austenite in the corrosion resistant bearing steel is 6 volume % or less.
    Type: Grant
    Filed: October 24, 2003
    Date of Patent: July 8, 2008
    Assignee: Kent Engineering
    Inventor: Toshiaki Miyauchi
  • Patent number: 7393420
    Abstract: Steel tubes for bearing element parts according to the present invention, wherein the specific compositions are limited and an accumulation intensity of {211} face along with an impact property at ambient temperature in the longitudinal direction of steel tube are specified, can be provided as a source material for bearing element parts, which have excellent machinability and fatigue life in rolling contact, being incorporated without adding a free-cutting element specifically nor without reducing productivity since the spheroidizing for the same annealing duration with that of conventional spheroidizing treatment can be applied. Accordingly, by applying a manufacturing method or a cutting-machining method according to the present invention, bearing element parts such as races, rollers and shafts can be produced with less cost and efficiently.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: July 1, 2008
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Yoshihiro Daito, Takashi Nakashima
  • Patent number: 7387692
    Abstract: Alloy tool steels of the present invention may be suitable for metalworking tools, bearings, gears, and specialized automotive parts, such as camshafts and lifters. A steel alloy, comprising: by weight, 0.5 to 1% carbon; 0.5 to 2.0% vanadium; 1.0 to 2.0% aluminum; 0.2 to 1.0% silicon; chromium; molybdenum; manganese; and iron. Further embodiments of the alloy tool steel consisting essentially of: by weight, 0.5 to 1% carbon; 0.5 to 1.5% vanadium; 1.0 to 2.0% aluminum; 0.2 to 1.0% silicon; 3.5 to 4.5% chromium; 0.1 to 0.5% manganese; 3.5 to 4.5% molybdenum; less than 0.05% nitrogen and the balance iron. In certain embodiments, the alloy tool steel comprises a ratio of the weight percentage of aluminum to the weight percentage of silicon in the range of 1.7 to 2.2.
    Type: Grant
    Filed: January 9, 2006
    Date of Patent: June 17, 2008
    Assignee: ATI Properties, Inc.
    Inventor: Wei-Di Cao
  • Patent number: 7371293
    Abstract: Cold finished seamless steel tubes are made such that the residual stress F to be generated at the stage of the correction process after cold working is controlled to be 30 MPa or more and the scattering thereof is 30 MPa or less, when measured by Crampton method. Further, by adjusting the average grain size of spheroidized carbides, the dimensional change which emerges in lathe turning of the outside and inside diameter of relevant steel tubes due to the residual strain can be suppressed, and the strict roundness as well as the excellent machinability can be secured at the final processing stage of the work pieces for bearing parts. Consequently, steel tubes with high dimensional accuracy and less dimensional change at the final steps such as lathe turning, heat treatment and the like, can be made for use as bearing parts.
    Type: Grant
    Filed: January 24, 2005
    Date of Patent: May 13, 2008
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Takashi Nakashima, Kouichi Kuroda, Kenichi Beppu
  • Patent number: 7371294
    Abstract: A high-strength cold-rolled steel sheet is disclosed that comprises a steel including C: 0.05 to 0.13 mass %, Si: 0.5 to 2.5 mass %, and Mn: 0.5 to 3.5 mass %, as well as Mo: 0.05 to 0.6 mass % and/or Cr: 0.05 to 1.0 mass %. The steel sheet is of composite structure of a ferrite+a second phase wherein the second phase has an area rate of 30 to 70% and is combined approximately in a shape of a network; a circle-equivalent average ferrite grain size is not more than 10 ?m; and a circle-equivalent diameter of ferrite grain aggregate that exists continuously in an area surrounded by the second phase is not more than 3 times of the average ferrite grain size. The steel sheet has a high-strength and satisfies a balance of elongation and stretch flange formability (ratio of hole expansion) at a higher level.
    Type: Grant
    Filed: January 31, 2005
    Date of Patent: May 13, 2008
    Assignee: Kobe Steel, Ltd.
    Inventors: Masaaki Miura, Yoichi Mukai, Yoshinobu Omiya, Shinji Kozuma
  • Patent number: 7314532
    Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average grain diameter of 5 ?m or less and a content represented by 50×[C]<[V?R]<150×[C], wherein [V?R] represents a space factor of the retained austenite (?R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.
    Type: Grant
    Filed: February 25, 2004
    Date of Patent: January 1, 2008
    Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Shushi Ikeda, Koichi Makii, Hiroshi Akamizu, Yoichi Mukai, Koh-ichi Sugimoto
  • Publication number: 20070272333
    Abstract: Disclosed is a hot rolled steel sheet in which it includes a steel having a chemical composition of 0.03 to 0.10% (the percent hereinafter representing % by mass) of C, 0.2 to 2.0% of Si, 0.5 to 2.5% of Mn, 0.02 to 0.10% of Al, 0.2 to 1.5% of Cr, 0.1 to 0.5% of Mo, and the residue of iron and inevitable contaminants, and in this steel sheet, at least 80% by area in longitudinal cross section has a martensitic structure. As a consequence, a high strength hot rolled steel sheet having a tensile strength of the level as high as 980 MPa or higher simultaneously with an excellent forming workability, and in particular, excellent stretch flangeability is provided at a relatively low cost.
    Type: Application
    Filed: April 12, 2007
    Publication date: November 29, 2007
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Kazuya KIMIJIMA, Tetsuo Soshiroda
  • Patent number: 7297177
    Abstract: A cold work steel has the following chemical composition in weight-%: 1.25-1.75% (C+N), however at least 0.5% C 0.1-1.5% Si 0.1-1.5% Mn 4.0-5.5% Cr 2.5-4.5% (Mo+W/2), however max. 0.5% W 3.0-4.5% (V+Nb/2), however max. 0.5% Nb max 0.3% S balance iron and unavoidable impurities, and a microstructure which in the hardened and tempered condition of the steel contains 6-13 vol-% of vanadium-rich MX-carbides, -nitrides and/or carbonitrides which are evenly distributed in the matrix of the steel, where X is carbon and/or nitrogen, at least 90 vol-% of said carbides, nitrides and/or carbonitrides having an equivalent diameter, Deq, which is smaller than 3.0 ?m; and totally max. 1 vol-% of other, possibly existing carbides, nitrides or carbonitrides.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: November 20, 2007
    Assignee: Uddeholm Tooling Aktiebolag
    Inventors: Odd Sandberg, Lennart Jönson, Magnus Tidesten
  • Patent number: 7264684
    Abstract: A steel for steel pipes which comprises, on the percent by mass basis, C: 0.2 to 0.7%, Si: 0.01 to 0.8%, Mn: 0.1 to 1.5%, S: 0.005% or less, P: 0.03% or less, Al: 0.0005 to 0.1%, Ti: 0.005 to 0.05%, Ca: 0.0004 to 0.005%, N: 0.007% or less, Cr: 0.1 to 1.5%, Mo: 0.2 to 1.0%, Nb: 0 to 0.1%, Zr: 0 to 0.1%, V: 0 to 0.5% and B: 0 to 0.005%, with the balance being Fe and impurities, in which non-metallic inclusions containing Ca, Al, Ti, N, O, and S are present, and in the said inclusions (Ca %)/(Al %) is 0.55 to 1.72, and (Ca %)/(Ti %) is 0.7 to 19 can be used as a raw material for oil country tubular goods, being used at a greater depth and in severer corrosive circumstances, such as casings and tubings for oil and/or natural gas wells, drilling pipes and drilling collars for excavation, and the like.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: September 4, 2007
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Mitsuhiro Numata, Tomohiko Omura, Yoshihiko Higuchi
  • Publication number: 20070199632
    Abstract: A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 ?m, prior austenite has a grain diameter of 30 ?m or less, and the ratio by volume of the residual austenite is less than 25%.
    Type: Application
    Filed: February 15, 2007
    Publication date: August 30, 2007
    Applicants: JFE Steel Corporation,a corporation of Japan, JTEKT Corporation, a corporation of Japan
    Inventors: Takashi Iwamoto, Kunikazu Tomita, Hideto Kimura, Takaaki Toyooka, Hisato Nishisaka, Masao Goto, Hisashi Harada
  • Publication number: 20070196685
    Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ??4.1?[Si]???2.4, ??(1) provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.
    Type: Application
    Filed: January 25, 2007
    Publication date: August 23, 2007
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yuichi Futamura, Katsuhiro Yamamoto, Masaaki Miura
  • Patent number: 7258756
    Abstract: The very thin, high carbon wire is 0.05 to 0.50 mm in diameter and comprises, in mass %, 0.90-1.20% of C, 0.05-1.2% of Si, 0.2-1.0% of Mn, and 0.0050% or less of N, with the balance being iron and impurities. In a differential scanning thermal analysis curve A of the steel wire, the steel wire has an exothermic peak X in the temperature range of 60° to 130° C., and a maximum height h of the exothermic peak X relative to a reference line Y joining the point of 60° C. and the point of 130° C. in the differential scanning thermal analysis curve is set at 5 ?W/mg or more. The very thin, high carbon steel wire is free of delamination in high-speed stranding and superior in both strength and ductility.
    Type: Grant
    Filed: October 20, 2004
    Date of Patent: August 21, 2007
    Assignee: Kobe Steel, Ltd.
    Inventors: Mamoru Nagao, Takeshi Kuroda, Takaaki Minamida
  • Patent number: 7252722
    Abstract: A steel sheet containing 0.004 to 0.02% C, 1.0% or less Si, 0.7 to 3.0% Mn, 0.02 to 0.15% P, 0.02% or less S, 0.01 to 0.1% Al, 0.004% or less N, 0.2% or less Nb, by mass %, optionally Ti, Bi or at least one element selected from the group consisting of Cr Mo, Ni and Cu, and the balance being Fe; the Nb content satisfying a formula of (12/93)×Nb*/C?1.0, wherein Nb*=Nb?(93/14)×N, and wherein C, N and Nb designate the content in mass % of carbon, nitrogen and niobium, respectively; and a yield strength and an average grain size of the ferritic grains which satisfy a formula of YP??120×d+1280, wherein YP designates yield strength in MPa, and d designates an average size of ferritic grains in ?m.
    Type: Grant
    Filed: March 2, 2004
    Date of Patent: August 7, 2007
    Assignee: NKK Corporation
    Inventors: Katsumi Nakajima, Takeshi Fujita, Toshiaki Urabe, Yuji Yamasaki, Fusato Kitano
  • Patent number: 7229507
    Abstract: A high speed tool steel, which is high in impact value and free from variations in tool performance, comprising, by mass %, of: 0.4?C?0.9; Si?1.0; Mn?1.0; 4?Cr?6; 1.5–6 in total of either or both of W and Mo in the form of (½W+Mo) wherein W?3; 0.5–3 in total of either or both of V and Nb in the form of (V+Nb); wherein carbides dispersed in the matrix of the tool steel have an average grain size of ?0.5 ?m and a dispersion density of particles of the carbides is of ?80×103 particles/mm2.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: June 12, 2007
    Assignee: Hitachi Metals, Ltd.
    Inventors: Shiho Fukumoto, Keiji Inoue
  • Patent number: 7211159
    Abstract: A ferritic heat-resistant steel, which exhibits excellent creep characteristics even at a high temperature exceeding 600° C., comprises, on the basis of percent by weight, 1.0 to 13% of chromium, 0.1 to 8.0% of cobalt, 0.01 to 0.20% of nitrogen, 3.0% or less of nickel, 0.01 to 0.50% of one or more of elements selected from a group consisting of vanadium, niobium, tantalum, titanium, hafnium, and zirconium that are MX type precipitate forming elements, and 0.01% or less of carbon and a balance being substantially iron and inevitable impurities, wherein the MX type precipitates precipitate on grain boundaries and in entire grains and the grain boundary existing ratio of an M23C6 type precipitate precipitating on the grain boundaries is 50% or less.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: May 1, 2007
    Assignees: National Institute for Materials Science, Mitsubishi Heavy Industries, Ltd.
    Inventors: Masaki Taneike, Fujio Abe
  • Patent number: 7105066
    Abstract: A welding structural steel product exhibiting a superior heat affected zone toughness, comprising, in terms of percent by weight, 0.03 to 0.17% C, 0.01 to 0.5% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.008 to 0.030% N, 0.0003 to 0.01% 0.00 1 to 0.2% W, at most 0.03% P, at most 0.03% S, at most 0.005% 0, and balance Fe and incidental impurities while satisfying conditions of 1.2?Ti/N?2.5, 10?N/B?40, 2.5?Al/N?7, and 6.5?(Ti+2Al+4B)/N?14, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 ?m or less. The method includes the steps of preparing a slab of the above-described composition, heating the slab to 1,100° C. to 1,250° C. for 60-180 minutes, hot rolling the heated slab in an austenite recrystallization range at a 40% or more rolling reduction followed by controlled cooling.
    Type: Grant
    Filed: November 16, 2001
    Date of Patent: September 12, 2006
    Assignee: Posco
    Inventors: Hong-Chul Jeong, Hae-Chang Choi
  • 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: 7083686
    Abstract: A steel product for oil country tubular good according to the invention comprises, in mass %, 0.10% to 0.35% C, 0.10% to 0.50% Si, 0.10% to 0.80% Mn, up to 0.030% P, up to 0.010% S, 0.30% to 1.20% Cr, 0.20% to 1.00% Mo, 0.005% to 0.40% V, 0.005% to 0. 100% Al, up to 0.0100% N, up to 0.0010% H, 0 to 0.01% Ca, 0 to 0.050% Ti, 0 to 0.050% Nb, and 0 to 0.0050% B, and the balance of Fe and impurities. The Cr, Mo, and V contents and the grain size GS satisfy expression (1): 0.7?(1.5×Cr+2.5×Mo+V)?GS/10?2.
    Type: Grant
    Filed: July 22, 2005
    Date of Patent: August 1, 2006
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventor: Takahito Itou
  • Patent number: 7074286
    Abstract: A high-strength, high-toughness steel alloy includes, generally, about 2.5% to about 4% chromium, about 1.5% to about 3.5% tungsten, about 0.1% to about 0.5% vanadium, and about 0.05% to 0.25% carbon with the balance iron, wherein the percentages are by total weight of the composition, wherein the alloy is heated to an austenitizing temperature and then cooled to produce an austenite transformation product.
    Type: Grant
    Filed: December 18, 2002
    Date of Patent: July 11, 2006
    Assignee: UT-Battelle, LLC
    Inventors: Ronald L. Klueh, Philip J. Maziasz, Vinod Kumar Sikka, Michael L. Santella, Sudarsanam Suresh Babu, Maan H. Jawad
  • Patent number: 7070664
    Abstract: A high strength bold superior in delayed fracture resistant property has a bolt tensile strength of 1200 N/mm2. A high strength bolt comprised of a head portion and shaft portion formed by a steel material, wherein the relation between a bolt tensile strength TS (N/mm2) and tempering temperature T (° C.) satisfies the following expression (1), the relation between the bolt tensile strength TS (N/mm2) and the carbon equivalent Ceq (%) calculated from the chemical composition of the steel material used for the high strength bolt satisfies the following expression (2), and the tensile strength of the bolt is refined to a range of 1200 N/mm2 to 1600 N/mm2 by quenching and tempering: TS?1.1T+850??(1) TS?550Ceq+1000??(2) where, C eq = C + ( Mn / 6 ) + ( Si / 24 ) + ( Ni / 40 ) + ( Cr / 5 ) + ( Mo / 4 ) + ( V / 14 ) .
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: July 4, 2006
    Assignee: Nippon Steel Corporation
    Inventors: Nobuyoshi Uno, Hideo Kanisawa
  • Patent number: 7048811
    Abstract: The present invention provides an electric resistance welded steel pipe for a hollow stabilizer excellent in workability, which steel pipe contains, in mass, 0.20 to 0.35% of C, 0.10 to 0.50% of Si, 0.30 to 1.00% of Mn, 0.01 to 0.10% of Al, 0.10 to 1.00% of Cr, 0.005 to 1.00% of Mo, 0.001 to 0.02% of Ti, 0.0005 to 0.0050% of B and 0.0010 to 0.0100% of N, satisfying the expression N/14<Ti/47.9, the balance consisting of Fe and unavoidable impurities and further has an ideal critical diameter (Di) being 1.0 (in) or more, an n-value in the axial direction of the steel pipe being 0.12 or more, a difference in hardness between the electric resistance welded seam portion and the base steel being Hv 30 or less, an average grain size of ferrite being 3 to 40 ?m, an area percentage of the ferritic crystal grains having the aspect ratios of 0.5 to 3.0 being 90% or more in the entire ferrite phase, and having an average grain size of 20 ?m or less in the second phase.
    Type: Grant
    Filed: March 4, 2002
    Date of Patent: May 23, 2006
    Assignee: Nippon Steel Corporation
    Inventors: Masahiro Ohgami, Tetsuya Magatani, Naoki Takasugi, Osamu Takeda
  • Patent number: 6974506
    Abstract: This invention relates to a method of manufacturing an improved ferritic or martensitic alloy based on iron and chromium strengthened by a dispersion of oxides, commonly called an Oxide Dispersion Strengthened or ODS alloy, and, more particularly to a method of manufacturing a ferritic or martensitic ODS alloy with large grains based on iron and chromium which has a single phase ferritic or martensitic matrix having an isotropic microstructure and a grain size that is sufficient to guarantee mechanical strength compatible with a use of this alloy at high temperature and/or under neutron irradiation. According to the invention, the method comprises slow cooling of an austenite at a cooling rate less than or equal to the critical cooling rate for transformation of this austenite into ferrite.
    Type: Grant
    Filed: September 25, 2002
    Date of Patent: December 13, 2005
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Véronique Lambard, Ana Alamo, Jean-Louis Seran
  • Patent number: 6966955
    Abstract: A weldable structural steel product having TiN and ZrN precipitates, which contains, in terms of percent by weight, 0.03 to 0.17% C, 0.01 to 0.5% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.001 to 0.03% Zr, 0.008 to 0.030% N, 0.0003 to 0.01% B, 0.001 to 0.2% W, at most 0.03% P, at most 0.03% S, at most 0.01% O, and balance Fe and incidental impurities while satisfying conditions of 1.2?Ti/N?2.5, 0.3?Zr/N?2.0, 10?N/B?40, 2.5?Al/N?7, and 6.8?(Ti+Zr+2Al+4B)/N?17, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 ?m or less.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: November 22, 2005
    Assignee: Posco
    Inventors: Hae-Chang Choi, Hong-Chul Jeong