Molybdenum Containing Patents (Class 148/334)
  • Patent number: 8865061
    Abstract: The invention relates to a steel alloy for a low alloy steel for producing high-tensile, weldable, hot-rolled seamless steel tubing, in particular construction tubing. The chemical composition (in % by mass) is: 0.15-0.18% C; 0.20-0.40% Si; 1.40-1.60% Mn; max. 0.05% P; max. 0.01% S; >0.50-0.90% Cr; >0.50-0.80% Mo; >0.10-0.15% V; 0.60-1.00% W; 0.0130-0.0220% N; the remainder is made up of iron with production-related impurities; with the optional addition of one or more elements selected from Al, Ni, Nb, Ti, with the proviso that the relationship V/N has a value of between 4 and 12 and the Ni content of the steel is not more than 0.40%.
    Type: Grant
    Filed: January 23, 2009
    Date of Patent: October 21, 2014
    Assignee: Vallourec Deutschland GmbH
    Inventors: Christoph Kaucke, Guido Kubla, Heinz Sanders, Charles Stallybrass, André Schneider, Markus Schütz
  • Patent number: 8821652
    Abstract: Steel for induction hardening wherein coarsening of austenite crystal grains can be prevented even at a high temperature of over 1100° C. such as which occurs at projecting parts of steel parts at the time of induction hardening, the steel for induction hardening characterized by containing, by mass %, C: 0.35 to 0.6%, Si: 0.01 to 1%, Mn: 0.2 to 1.8%, S: 0.001 to 0.15%, Al: 0.001 to 1%, Ti: 0.05 to 0.2%, and Nb: 0.001 to 0.04%, restricting N: 0.0060% or less, P: 0.025% or less, and O: 0.0025% or less, satisfying Nb/Ti?0.015, and having a balance of iron and unavoidable impurities.
    Type: Grant
    Filed: October 7, 2010
    Date of Patent: September 2, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Shuji Kozawa, Manabu Kubota
  • Publication number: 20140230969
    Abstract: Provided is a TRIP-aided dual-phase martensitic steel which is excellent in terms of strength-elongation balance and Charpy impact value and has dual-phase martensite composed of a soft lath martensitic structure and a hard lath martensitic structure as a matrix phase, regardless of forging temperature or forging reduction ratio, by controlling heat treatment conditions. The dual-phase martensitic steel contains 0.1-0.7% C, 0.5-2.5% Si, 0.5-3.0% Mn, 0.5-2.0% Cr, 0.5% or less (including 0%) of Mo, 0.04-2.5% Al, and the balance Fe with incidental impurities; has its metallographic structure in which a matrix phase is composed of a soft lath martensitic structure and a hard lath martensitic structure; and obtained by heating its raw steel material to a ?-range, rapidly cooling the heated material to a temperature slightly above a martensite transformation starting temperature (Ms), and then performing an isothermal transformation process the cooled material in the temperature range from Mf to [(Mf)?100° C].
    Type: Application
    Filed: March 14, 2012
    Publication date: August 21, 2014
    Applicants: USUI KOKUSAI SANGYO KAISHA LIMITED, SHINSU UNIVERSITY
    Inventors: Koh-ichi Sugimoto, Junya Kobayashi, Nobuo Yoshikawa, Yuji Nakajima, Teruhisa Takahashi, Goro Arai
  • Publication number: 20140212660
    Abstract: Disclosed is a medium carbon steel sheet for cold working that has a hardness of 500 HV to 900 HV when subjected to high-frequency quenching in which a temperature is raised at an average heating rate of 100° C./second, the temperature is held at 1,000° C. for 10 seconds, and a quick cooling to a room temperature is carried out at an average cooling rate of 200° C./second. The medium carbon steel sheet includes, by mass %, C: 0.30 to 0.60%, Si: 0.06 to 0.30%, Mn: 0.3 to 2.0%, P: 0.03% or less, S: 0.0075% or less, Al: 0.005 to 0.10%, N: 0.001 to 0.01%, and Cr: 0.001 to 0.10%, the balance composed of Fe and inevitable impurities. An average diameter d of a carbide is 0.6 ?m or less, a spheroidizing ratio p of the carbide is equal to or more than 70% and less than 90%, and the average diameter d (?m) of the carbide and the spheroidizing ratio p % of the carbide satisfy d?0.04×p?2.6.
    Type: Application
    Filed: September 22, 2011
    Publication date: July 31, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kengo Takeda, Masayuki Abe, Yasushi Tsukano, Takashi Aramaki, Shinichi Yamaguchi
  • Patent number: 8784577
    Abstract: A high-tensile-strength hot-rolled steel sheet is provided having a composition which contains 0.02 to 0.08% C, 0.01 to 0.10% Nb, 0.001 to 0.05% Ti and Fe and unavoidable impurities as a balance, wherein the steel sheet contains C, Ti and Nb in such a manner that (Ti+(Nb/2))/C<4 is satisfied, and the steel sheet has a structure where a primary phase of the structure at a position 1 mm away from a surface in a sheet thickness direction is one selected from a group consisting of a ferrite phase, tempered martensite and a mixture structure of a ferrite phase and tempered martensite, a primary phase of the structure at a sheet thickness center position is formed of a ferrite phase, and a difference ?V between a structural fraction (volume %) of a secondary phase at the position 1 mm away from the surface in the sheet thickness direction and a structural fraction (volume %) of a secondary phase at the sheet thickness center position is 2% or less.
    Type: Grant
    Filed: January 29, 2010
    Date of Patent: July 22, 2014
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Hiroshi Nakata, Kinya Nakagawa
  • Patent number: 8778096
    Abstract: Provided is a low yield ratio, high strength and high toughness steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. The steel plate has a metallographic microstructure that is a three-phase microstructure including bainite, M-A constituent, and quasi-polygonal ferrite, the area fraction of the bainite being 5% to 70%, the area fraction of the M-A constituent being 3% to 20%, the remainder being the quasi-polygonal ferrite, the equivalent circle diameter of the M-A constituent being 3.0 ?m or less. The steel plate has a yield ratio of 85% or less and a Charpy impact test absorbed energy of 200 J or more at ?30° C. before or after being subjected to strain ageing treatment at a temperature of 250° C. or lower for 30 minutes or less.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: July 15, 2014
    Assignee: JFE Steel Corporation
    Inventors: Junji Shimamura, Nobuyuki Ishikawa, Nobuo Shikanai
  • Publication number: 20140162088
    Abstract: High strength steel sheet and high strength galvanized steel sheet which are excellent in shapeability which secure a tensile maximum strength 900 MPa or more high strength while obtaining excellent ductility and stretch flangeability, which sheets have predetermined compositions of ingredients, have steel sheet structures which contain volume fraction 1 to 20% of residual austenite phases, and which have martensite transformation points of the residual austenite phases of ?60° C. or less.
    Type: Application
    Filed: July 27, 2012
    Publication date: June 12, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Takeshi Yasui, Yuji Yamaguchi, Natsuko Sugiura
  • Publication number: 20140150930
    Abstract: The present invention relates to a hot press forming steel plate made of a composition comprising: 0.3-1.0 wt % of C; 0.0-4.0 wt % of Mn; 1.0-2.0 wt % of Si; 0.01-2.0 wt % of Al; 0.015 wt % or less of S; 0.01 wt % or less of N; and the remainder being Fe and unavoidable impurities. Further, the present. invention relates to a method for manufacturing the hot press forming steel plate, characterized by comprising the steps of: heating, to between 1100 and 1300° C., a steel slab having the composition; performing hot rolling finishing between. an Ar3 transformation point and 950° C.; and performing winding between MS and 720° C. Further, the present invention. relates to a hot press formed member characterized by having the composition, and having a dual phase microstructure made of bainite and residual austenite.
    Type: Application
    Filed: July 15, 2011
    Publication date: June 5, 2014
    Inventors: Kyoo-Young Lee, Jin-Keun Oh, Jong-Sang Kim, Tae-Kyo Han
  • Patent number: 8741216
    Abstract: Disclosed is steel for a leaf spring with high fatigue strength containing, in mass percentage, C: 0.40 to 0.54%, Si: 0.40 to 0.90%, Mn: 0.40 to 1.20%, Cr: 0.70 to 1.50%, Ti: 0.070 to 0.150%, B: 0.0005 to 0.0050%, N: 0.0100% or less, and a remainder composed of Fe and impurity elements. Also disclosed is a high fatigue-strength leaf spring part obtained by forming the steel. The steel for a leaf spring is prepared to have a Ti content and a N content to satisfy a relation of Ti/N?10. Preferably, the leaf spring part is subjected to a shot peening treatment in a temperature range of the room temperature through 400° C. with a bending stress of 650 to 1900 MPa being applied to it.
    Type: Grant
    Filed: December 15, 2010
    Date of Patent: June 3, 2014
    Assignee: NHK Spring Co., Ltd.
    Inventors: Atsushi Sugimoto, Kiyoshi Kurimoto, Akira Tange, Yurika Goto, Mamoru Akeda
  • Publication number: 20140144551
    Abstract: A high-strength steel sheet having improved HIC resistance and fracture resistance even when it is thick has a chemical composition comprising, in mass %, C: 0.02-0.07%, Si: 0.05-0.50%, Mn: 1.10-1.60%, P: at most 0.015%, S: at most 0.0030%, Nb: 0.005-0.030%, Ti: 0.005-0.020%, Al: 0.005-0.060%, Ca: 0.0005-0.0060%, N: 0.0015-0.0070%, at least one of Cu, Ni, Cr, and Mo in a total of greater than 0.1% to less than 1.5%, and a remainder of Fe and impurities and a steel structure composed of at least 10% by area of bainite and a remainder of ferrite and pearlite. The degree of segregation is less than 1.6 for Nb and less than 1.4 for Mn in the central portion of the thickness of the steel sheet.
    Type: Application
    Filed: September 2, 2011
    Publication date: May 29, 2014
    Inventors: Izuru Minato, Nobuaki Takahashi, Akio Yamamoto
  • Patent number: 8734600
    Abstract: High strength steel wire for spring containing, by mass %, C: 0.67% to less than 0.75%, Si: 2.0 to 2.5%, Mn: 0.5 to 1.2%, Cr: 0.8 to 1.3%, V: 0.03 to 0.20%, Mo: 0.05 to 0.25%, W: 0.05 to 0.30%, and N: 0.003 to 0.007%, having a total of contents of Mn and V of 0.70%?Mn+V?1.27% and a total of contents of Mo and W of 0.13%?Mo+W?0.35%, limiting P: 0.025% or less, S: 0.025% or less, and Al: 0.003% or less, and having a balance of iron and unavoidable impurities, having a microstructure comprised of, by volume percent, over 6% to 15% of retained austenite and tempered martensite, having a prior-austenite grain size number of 10 or more, having a density of presence of spheroidal carbides with a circle equivalent diameter of 0.2 to 0.5 ?m of 0.06 particles/?m2 or less, having a density of presence of spheroidal carbides with a circle equivalent diameter of over 0.5 ?m of 0.01 particles/?m2 or less, and having a tensile strength of 2100 to 2350 MPa.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: May 27, 2014
    Assignees: Nippon Steel & Sumitomo Metal Corporation, Suzuki Metal Industry Co., Ltd., Honda Motor Co., Ltd.
    Inventors: Masayuki Hashimura, Hitoshi Demachi, Takayuki Kisu, Shoichi Suzuki, Motonobu Suehiro, Jun Kawaguchi, Keiichi Maekawa, Atsushi Murakami
  • Patent number: 8715432
    Abstract: The present invention provides high temperature strength and fire-resistant steel superior in weld joint reheat embrittlement resistance and toughness which is produced using steel of a room temperature strength of the 400 to 600N/mm2 class containing as main ingredients C: 0.010% to less than 0.05%, Si: 0.01 to 0.50%, Mn: 0.80 to 2.00%, Cr: 0.50% to less than 2.00%, V: 0.03 to 0.30%, Nb: 0.01 to 0.10%, N: 0.001 to 0.010%, and Al: 0.005 to 0.10%, limiting the contents of Ni, Cu, Mo, and B, and satisfying the relationship of 4Cr[%]-5Mo[%]-10Ni[%]-2Cu[%]-Mn[%]>0.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: May 6, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Yasushi Hasegawa, Masaki Mizoguchi, Yoshiyuki Watanabe, Suguru Yoshida, Tadayoshi Okada
  • 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: 8696834
    Abstract: A method for suppressing shock and storage cracking when manufacturing seamless steel pipes comprises hot piercing and hot rolling a billet consisting of, by mass percent controlled amounts of C, Si, Mn, Cr, Mo, Ti, and Al, with the balance being Fe and impurities of Ni, P, S, N, and O also in controlled amounts. Further heat treatment is performed, wherein a hot rolled steel pipe is direct quenched from a temperature of not lower than the Ar3 transformation point and the pipe is then subjected to heat treatment at a temperature of not lower than 450° C. and not higher than the Ac1 transformation point in heat treatment equipment for performing direct quenching. The steel pipe subjected to the heat treatment is reheated, quenched from a temperature of not lower than the Ac3 transformation point, and tempered at a temperature of not higher than the Ac1 transformation point.
    Type: Grant
    Filed: September 20, 2011
    Date of Patent: April 15, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Keiichi Kondo, Toshiharu Abe, Kunio Kondo, Yuichi Yano, Yuji Arai
  • Patent number: 8685182
    Abstract: This high-strength steel pipe includes, by mass %, C: 0.02% to 0.09%, Mn: 0.4% to 2.5%, Cr: 0.1% to 1.0%, Ti: 0.005% to 0.03%, Nb: 0.005% to 0.3%, and a balance consisting of Fe and inevitable impurities, in which Si, Al, P, S, and N are limited to 0.6% or less, 0.1% or less, 0.02% or less, 0.005% or less, 0.008% or less, respectively, the bainite transformation index BT is 650° C. or less, and the microstructure thereof is a single bainite microstructure including first bainite and second bainite, the first bainite being a gathered microstructure of bainitic ferrite including no carbide, and the second bainite being a mixed microstructure of bainitic ferrite including no carbide and cementite between the bainitic ferrites.
    Type: Grant
    Filed: June 10, 2010
    Date of Patent: April 1, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kensuke Nagai, Yasuhiro Shinohara, Shinya Sakamoto, Takuya Hara, Hitoshi Asahi
  • Patent number: 8679265
    Abstract: The invention provides a high-strength cold-rolled steel sheet which is improved in elongation and stretch-flangeability and exhibits more excellent formability. The high-strength cold-rolled steel sheet has a composition which contains by mass C: 0.03 to 0.30%, Si: 0.1 to 3.0%, Mn: 0.1 to 5.0%, P: 0.1% or below, S: 0.005% or below, N: 0.01% or below, and Al: 0.01 to 1.00% with the balance consisting of iron and unavoidable impurities. The high-strength cold-rolled steel sheet has a structure which comprises at least 40% (up to 100% inclusive) in terms of area fraction of tempered martensite having a hardness of 300 to 380 Hv and the balance ferrite. The cementite particles in the tempered martensite take such dispersion that 10 or more cementite particles having equivalent-circle diameters of 0.02 to less than 0.1 ?m are present per one ?m2 of the tempered martensite and three or fewer cementite particles having equivalent-circle diameters of 0.
    Type: Grant
    Filed: November 20, 2008
    Date of Patent: March 25, 2014
    Assignee: Kobe Steel, Ltd.
    Inventors: Toshio Murakami, Hideo Hata, Akira Ibano, Kenji Saito
  • Publication number: 20140076470
    Abstract: The present invention provides a method for the fabrication of a steel sheet with a completely martensitic structure which has an average lath size of less than 1 micrometer and an average elongation factor of the laths is between 2 and 5. The elongation factor of a lath is defined as a maximum dimension divided by and a minimum dimension 1max. The steel sheet has a yield stress greater than 1300 MPa and a mechanical strength greater than (3220(C)+958) megapascals. A composition of a semi-finished steel product includes, expressed in percent by weight, is, 0.15%?C?0.40%, 1.5%?Mn?3%, 0.005%?Si?2%, 0.005%?Al?0.1%, 1.8%?Cr?4%, 0%?Mo?2%, whereby: 2.7%?0.5 (Mn)+(Cr)+3(Mo)?5.7%, S?0.05%, P?0.1%, optionally: 0%?Nb?0.050%, 0.01%?Ti?0.1%, 0.0005%?B?0.005%, 0.0005%?Ca?0.005%. The semi-finished product is reheated to a temperature T1 in the range between 1050° C. and 1250° C., then subjected to a roughing rolling at a temperature T2 in the range between 1000 and 880° C.
    Type: Application
    Filed: April 20, 2012
    Publication date: March 20, 2014
    Inventors: Kangying Zhu, Olivier Bouaziz
  • Patent number: 8673093
    Abstract: The present invention is the thin steel sheet containing C, Si, Mn, P, S, Al, Mo, Ti, B, and N wherein a value Z calculated by the equation described below is 2.0-6.0, an area ratio against all the structure is 1% or above for retained austenite and 80% or above for total of bainitic ferrite and martensite, a mean axis ratio of the retained austenite crystal grain is 5 or above, and tensile strength is 980 MPa or above where Value Z=9×[C]+[Mn]+3×[Mo]+490×[B]+7×[Mo]/{100×([B]+0.001),and the thin steel sheet has 980 MPa or above tensile strength and enhanced hydrogen embrittlement resistance properties.
    Type: Grant
    Filed: December 10, 2007
    Date of Patent: March 18, 2014
    Assignee: Kobe Steel, Ltd.
    Inventors: Muneaki Ikeda, Kouji Kasuya, Yoichi Mukai, Fumio Yuse, Junichiro Kinugasa
  • Publication number: 20140060706
    Abstract: Disclosed is high strength spring steel that can limit the depth of pitting occurring when corroded and therefore possesses high strength as well as excellent pitting corrosion resistance and corrosion fatigue property, with a composition containing: C: greater than 0.35 mass % and less than 0.50 mass %; Si: greater than 1.75 mass % and less than or equal to 3.00 mass %; Mn: 0.2 mass % to 1.0 mass %; Cr: 0.01 mass % to 0.04 mass %; P: 0.025 mass % or less; S: 0.025 mass % or less; Mo: 0.1 mass % to 1.0 mass %; and O: 0.0015 mass % or less, under a condition that a PC value calculated by PC=4.2×([C]+[Mn])+0.1×(1/[Si]+1/[Mo])+20.3×[Cr]+0.001×(1/[N]) is greater than 3.3 and equal to or less than 8.0. Also disclosed is a preferred method for manufacturing the same.
    Type: Application
    Filed: November 8, 2013
    Publication date: March 6, 2014
    Applicant: JFE STEEL CORPORATION
    Inventors: Minoru HONJO, Kazukuni HASE, Hideto KIMURA
  • Patent number: 8663400
    Abstract: Provided is a low alloy steel for high-pressure hydrogen gas environments, which contains, by mass percent, C: 0.15 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.05 to 3.0%, P: not more than 0.025%, S: not more than 0.010%, Al: 0.005 to 0.10%, Mo: 0.5 to 3.0%, V: 0.05 to 0.30%, O (oxygen): not more than 0.01%, N: not more than 0.03%, and the balance Fe and impurities, and has tensile strength of not less than 900 MPa. This low alloy steel desirably contains B of 0.0003 to 0.003%, but in this case, N is limited to not more than 0.010%. It is desirable to contain at least one among Cr, Nb, Ti, Zr, and Ca. The contents of Mo and V desirably satisfy the following formula (1): [Mo(%)]·[V(%)]0.2?0.32??(1).
    Type: Grant
    Filed: June 12, 2009
    Date of Patent: March 4, 2014
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Tomohiko Omura, Mitsuo Miyahara, Hiroyuki Semba, Masaaki Igarashi
  • Patent number: 8657969
    Abstract: A high strength galvanized steel sheet has a TS of 590 MPa or more and excellent processability. The component composition contains, by mass %, C: 0.05% to 0.3%, Si: 0.7% to 2.7%, Mn: 0.5% to 2.8%, P: 0.1% or lower, S: 0.01% or lower, Al: 0.1% or lower, and N: 0.008% or lower, and the balance: Fe or inevitable impurities. The microstructure contains, in terms of area ratio, ferrite phases: 30% to 90%, bainite phases: 3% to 30%, and martensite phases: 5% to 40%, in which, among the martensite phases, martensite phases having an aspect ratio of 3 or more are present in a proportion of 30% or more.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: February 25, 2014
    Assignee: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Tatsuya Nakagaito, Shinjiro Kaneko, Saiji Matsuoka
  • Patent number: 8647449
    Abstract: Disclosed herein are iron-based alloys having a microstructure comprising a fine-grained ferritic matrix and having a 60+ Rockwell C surface, wherein the ferritic matrix comprises <10 ?m carbide precipitates. Also disclosed are methods of welding comprising forming a crack free hardbanding weld overlay coating with such an iron-based alloy. Also disclosed are families of alloys capable of forming crack-free weld overlays after multiple welding passes.
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: February 11, 2014
    Assignee: Scoperta, Inc.
    Inventors: Justin Lee Cheney, John Hamilton Madok
  • Patent number: 8628630
    Abstract: A hot-pressed steel sheet member has a composition containing, by mass, C: 0.09% to 0.38%, Si: 0.05% to 2.0%, Mn: 0.5% to 3.0%, P: 0.05% or less, S: 0.05% or less, Al: 0.005% to 0.1%, N: 0.01% or less, Sb: 0.002% to 0.03%, and the balance being Fe and inevitable impurities, and having a tensile strength TS of 980 to 2,130 MPa.
    Type: Grant
    Filed: August 19, 2010
    Date of Patent: January 14, 2014
    Assignee: JFE Steel Corporation
    Inventors: Akio Kobayashi, Yoshimasa Funakawa, Kazuhiro Seto, Nobuyuki Kageyama, Tetsuo Yamamoto, Toru Hoshi, Takeshi Yokota
  • Patent number: 8617462
    Abstract: A steel for an oil well pipe, having high strength and excellent SSC resistance, consists of, by mass %, C: 0.30 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.05 to 1.0%, Al: 0.005 to 0.10%, Cr+Mo: 1.5 to 3.0%, wherein Mo is 0.5% or more, V: 0.05 to 0.3%, Nb: 0 to 0.1%, Ti: 0 to 0.1%, Zr: 0 to 0.1%, N (nitrogen): 0 to 0.03%, Ca: 0 to 0.01%, and the balance Fe and impurities; P 0.025% or less, S 0.01% or less, B 0.0010% or less and O (oxygen) 0.01% or less. The method involves heating the steel at 1150° C. or more; producing a seamless steel pipe by hot working; water-cooling the pipe to a temperature in a range of 400 to 600° C. immediately after finishing the working; and subjecting the pipe to a heat treatment for bainite isothermal transformation in a range of 400 to 600° C.
    Type: Grant
    Filed: September 21, 2007
    Date of Patent: December 31, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventor: Tomohiko Omura
  • Publication number: 20130340899
    Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.
    Type: Application
    Filed: March 9, 2011
    Publication date: December 26, 2013
    Inventors: Kazuhisa Kusumi, Yuji Ogawa, Masayuki Abe, Hidekuni Murakami, Kengo Takeda, Jun Maki
  • Patent number: 8608874
    Abstract: Disclosed is high strength spring steel that can limit the depth of pitting occurring when corroded and therefore possesses high strength as well as excellent pitting corrosion resistance and corrosion fatigue property, with a composition containing: C: greater than 0.35 mass % and less than 0.50 mass %; Si: greater than L75 mass % and less than or equal to 3.00 mass %; Mn: 0.2 mass % to 1.0 mass %; Cr: 0.01 mass % to 0.04 mass %; P: 0.025 mass % or less; S: 0.025 mass % or less; Mo: 0.1 mass % to 1.0 mass %; and 0: 0.0015 mass % or less, under a condition that a PC value calculated by PC=4.2×([C]+[Mn])+0.1×(1/[Si]+1/[Mo])+20.3×[Cr]+0.001×(1/[N]) is greater than 3.3 and equal to or less than 8.0. Also disclosed is a preferred method for manufacturing the same.
    Type: Grant
    Filed: February 28, 2011
    Date of Patent: December 17, 2013
    Assignee: JFE Steel Corporation
    Inventors: Minoru Honjo, Kazukuni Hase, Hideto Kimura
  • Patent number: 8591672
    Abstract: The invention provides medical devices comprising high-strength alloys which degrade over time in the body of a human or animal, at controlled degradation rates, without generating emboli. In one embodiment the alloy is formed into a bone fixation device such as an anchor, screw, plate, support or rod. In another embodiment the alloy is formed into a tissue fastening device such as staple. In yet another embodiment, the alloy is formed into a dental implant or a stent.
    Type: Grant
    Filed: July 19, 2012
    Date of Patent: November 26, 2013
    Assignee: Bio DG, Inc.
    Inventors: Gordon F. Janko, Herbert R. Radisch, Thomas A. Trozera
  • Patent number: 8585835
    Abstract: A high-strength steel machined product giving excellent hardenability has a metal microstructure with excellent balance of strength and toughness and high stability of retained austenite. The product is composed of an ultra-high low-alloy TRIP steel having a metal microstructure which contains an appropriate quantity of two or more of Cr, Mo, and Ni, and an appropriate quantity of one or more of Nb, Ti, and V, and having an appropriate value of carbon equivalent; the metal microstructure has a mother-phase structure composed mainly of lathy bainitic ferrite with a small amount of granular bainitic ferrite and polygonal ferrite, and has a secondary-phase structure composed of fine retained austenite and martensite.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: November 19, 2013
    Assignees: Usui Kokusai Sangyo Kaisha Limited, Shinshu University
    Inventors: Koh-ichi Sugimoto, Sho-hei Sato, Teruhisa Takahashi, Goro Arai
  • Publication number: 20130295402
    Abstract: Provided is a steel sheet for a formed member having enhanced ductility, a formed member, and a method for manufacturing the formed member, and more particularly, to a steel sheet for making a formed member having high strength and ductility such as an automotive structural member and a reinforcing member, a formed member, and a method for manufacturing the formed member. The steel sheet for a formed member has enhanced ductility, and includes, by weight %, C: 0.1% to 1.0%, Si+Al: 0.4% to 3.0%, Mn: 0.1% to 5.0%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, N: 0.03% or less (but not 0%), and the balance of Fe and inevitable impurities. The formed member having high strength and ductility that can be used for forming an automotive structural member, a reinforcing member, etc. In addition, the formed member can be used for a heat-treatable impact resistant member.
    Type: Application
    Filed: December 14, 2011
    Publication date: November 7, 2013
    Applicant: POSCO
    Inventors: Jin-Keun Oh, Jai-Hyun Kwak, Yeol-Rae Cho, Ki-Soo Kim
  • Publication number: 20130248060
    Abstract: A strain aging hardening type steel sheet excellent in aging resistance, and manufacturing method thereof, said steel sheet comprises: in mass %, C: 0.0010 to 0.010%; Si: 0.005 to 1.0%; Mn: 0.08 to 1.0%; P: 0.003 to 0.10%; S: 0.0005 to 0.020%; Al: 0.010 to 0.10%; Cr: 0.005 to 0.20%; Mo: 0.005 to 0.20%; Ti: 0.002 to 0.10%; Nb: 0.002 to 0.10%; N: 0.001 to 0.005%; and a balance being composed of Fe and inevitable impurities, in which a ferrite fraction is 98% or more, an average grain diameter of ferrite is 5 to 30 ?m, a minimum value of dislocation density in a portion having a ½ thickness of a sheet thickness and a minimum value of dislocation density in a surface layer portion are each 5×1012/m2 or more, and an average dislocation density falls within a range of 5×1012 to 1×1015/m2.
    Type: Application
    Filed: June 22, 2011
    Publication date: September 26, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Naoki Maruyama, Koji Hashimoto, Masaharu Kameda
  • Publication number: 20130240094
    Abstract: The present invention provides a bake-hardenable high-strength cold-rolled steel sheet having excellent bake hardenability, cold aging resistance, and deep-drawability, and reduced planar anisotropy, containing chemical components in % by mass of: C: 0.0010% to 0.0040%, Si: 0.005% to 0.05%, Mn: 0.1% to 0.8%, P: 0.01% to 0.07%, S: 0.001% to 0.01%, Al: 0.01% to 0.08%, N: 0.0010% to 0.0050%, Nb: 0.002% to 0.020%, and Mo: 0.005% to 0.050%, a value of [Mn %]/[P %] being in the range of 1.6 to 45, where [Mn %] is an amount of Mn and [P %] is an amount of P, an amount of C in solid solution obtained from [C %]?(12/93)×[Nb %] being in the range of 0.0005% to 0.
    Type: Application
    Filed: April 27, 2011
    Publication date: September 19, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Satoshi Akamatsu, Masaharu Oka
  • Patent number: 8535459
    Abstract: The present invention provides a steel material for hardening, including chemical components, by mass %, of: C: 0.15 to 0.60%; Si: 0.01 to 1.5%; Mn: 0.05 to 2.5%; P: 0.005 to 0.20%; S: 0.001 to 0.35%; Al: over 0.06 to 0.3%; and total N: 0.006 to 0.03%, with a balance including Fe and inevitable impurities including B of not more than 0.0004%, in which a hardness R at a position 5 mm away from a quenching end measured through a Jominy-type end-quenching method specified in JIS G 0561, and a calculation hardness H at a position 4.763 mm away from the quenching end satisfy the following Equation (1). H×0.948?R?H×1.
    Type: Grant
    Filed: May 17, 2011
    Date of Patent: September 17, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kei Miyanishi, Manabu Kubota, Shuji Kozawa
  • Publication number: 20130213529
    Abstract: A high-strength cold rolled steel sheet having excellent deep drawability and bake hardenability, with a tensile strength ?440 MPa, an average r-value ?1.20 and a bake hardening value ?40 MPa, is obtained by subjecting a steel raw material having a chemical composition including C: 0.010-0.06 mass %, Si: more than 0C:\Users\ejensen\Desktop\!TEMP\.5 mass % but not more than 1.5 mass %, Mn: 1.0-3.0 mass %, Nb: 0.010-0.090 mass %, Ti: 0.015-0.15 mass % and satisfying (Nb/93)/(C/12)<0.20 to hot rolling, cold rolling and then to annealing including steps of heating to a temperature of 800-900° C. while a temperature region of 700-800° C. is an average heating rate <3° C./s, and soaking and thereafter cooling at a rate ?5° C./s from the soaking temperature to a cooling stop temperature ?500° C. to thereby form a microstructure including ferrite phase with an area ratio ?70% and martensite phase with an area ratio ?3%.
    Type: Application
    Filed: October 28, 2011
    Publication date: August 22, 2013
    Applicant: JFE Steel Corporation
    Inventors: Hideyuki Kimura, Yasunobu Nagataki
  • Publication number: 20130199678
    Abstract: A high strength hot-rolled steel sheet with a tensile strength of not less than 590 MPa which exhibits excellent bake hardenability and stretch-flangeability has a chemical composition including, in terms of mass %, C at 0.040 to 0.10%, Si at not more than 0.3%, Mn at 1.7 to 2.5%, P at not more than 0.030%, S at not more than 0.005%, Al at not more than 0.1% and N at 0.006 to 0.025%, and microstructure wherein a bainite phase represents not less than 60%, the total of a ferrite phase and a pearlite phase represents not more than 10%, and the bainite phase includes grains among which cementite grains have been precipitated at not less than 1.4×104 grains/mm2 and the cementite grains have an average grain diameter of not more than 1.5 ?m.
    Type: Application
    Filed: May 23, 2011
    Publication date: August 8, 2013
    Applicant: JFE STEEL CORPORATION
    Inventors: Noriaki Kohsaka, Kazuhiro Seto, Hidetaka Kawabe, Yasushi Tanaka
  • Publication number: 20130192724
    Abstract: A high-strength steel sheet has a chemical composition comprising C: 0.05-0.20%, Si: 0.02-3.0%, Mn: 0.5-3.0%, P: at most 0.5%, S: at most 0.05%, Cr: 0.05-1.0%, sol. Al: 0.01-1.0%, one or more elements selected from the group consisting of Ti, Nb, Mo, V, and W: a total of 0.002-0.03%, and a remainder of Fe and impurities. The sheet has an average grain diameter of ferrite of at most 3.0 ?m at least in a region of 100-200 ?m in the sheet thickness direction from the surface of the steel sheet. The average spacing in the sheet thickness direction of the remaining structure in this region is at most 3.0 ?m. Mechanical properties include at least 750 MPa tensile strength and at least 13,000 MPa·% (tensile strength×elongation).
    Type: Application
    Filed: May 27, 2010
    Publication date: August 1, 2013
    Applicant: Nippon Steel & Sumitomo Metal Coporation
    Inventors: Yasuaki Tanaka, Toshiro Tomida, Kaori Kawano
  • Publication number: 20130192726
    Abstract: A method of hot forming a steel blank into an article the method including the following steps: d) cooling a heated steel blank to form an article during hot forming, starting at a starting temperature T2 above Ar3; to an interrupt temperature T3 in the range of 400-550° C. at a cooling rate V2 of at least 25° C./s; e) immediately further cooling the article from the interrupt temperature T3 to ambient temperature at a cooling rate V3 of 0.2-10° C./s, wherein the interrupt temperature T3 and cooling rate V3 are selected such that the article thus obtained has multiphase microstructure including by volume fraction: 55-90% of bainitic ferrite 5-15% of retained austenite 5-30% martensite.
    Type: Application
    Filed: October 10, 2011
    Publication date: August 1, 2013
    Applicant: TATA STEEL IJMUIDEN B.V.
    Inventors: Shangping Chen, Christiaan Theodorus Wilhelmus Lahaye
  • Patent number: 8496763
    Abstract: A seamless steel tube for an airbag accumulator which can be manufactured by heat treatment of normalizing without quenching and tempering and which has a tensile strength of at least 850 MPa and resistance to bursting at ?20° C. has a stee; composition comprising, in mass %, C: 0.08-0.20%, Si: 0.1-1.0%, Mn: 0.6-2.0%, P: at most 0.025%, S: at most 0.010%, Cr: 0.05-1.0%, Mo: 0.05-1.0%, Al: 0.002-0.10%, at least one of Ca: 0.0003-0.01%, Mg: 0.0003-0.01%, and REM (rare earth metals): 0.0003-0.01%, at least one of Ti: 0.002-0.1% and Nb: 0.002-0.1%, with Ceq which is defined by the following Equation (1) being in the range of 0.45-0.63, with the metallurgical structure being a mixed structure of ferrite+bainite: Ceq=C+Si/24+Mn/6+(Cr+Mo)/5+(Ni+Cu)/15??(1) wherein the symbol for each element in Equation (1) indicates the number expressing the mass percent of the element.
    Type: Grant
    Filed: April 24, 2009
    Date of Patent: July 30, 2013
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Yuji Arai, Takashi Takano
  • Publication number: 20130186521
    Abstract: This profiled wire, of NACE grade, made of low-alloy carbon steel intended to be used in the offshore oil exploitation sector, is characterized in that it has the following chemical composition, expressed in percentages by weight of the total mass: 0.75<% C<0.95; 0.30<% Mn<0.85; Cr?0.4%; V?0.16%; Si?1.40% and preferably ?0.15%; and optionally no more than 0.06% Al, no more than 0.1% Ni and no more than 0.
    Type: Application
    Filed: March 23, 2011
    Publication date: July 25, 2013
    Applicant: ARCELOMITTAL WIRE FRANCE
    Inventors: Sylvain Foissey, Christophe Bertout, Xavier Perroud
  • Patent number: 8491732
    Abstract: A hot-rolled steel bar or wire rod consisting of C: 0.1 to 0.3%, Si: 0.05 to 1.5%, Mn: 0.4 to 2.0%, S: 0.003 to 0.05%, Cr: 0.5 to 3.0%, Al: 0.02 to 0.05%, and N: 0.010 to 0.025%, the balance being Fe and impurities, and the impurities containing P: 0.025% or less, Ti: 0.003% or less, and O: 0.002% or less, wherein the structure thereof is composed of a ferrite-pearlite structure, ferrite-pearlite-bainite structure, or ferrite-bainite structure; the standard deviation of ferrite fractions at the time when randomly selected 15 viewing fields of a transverse cross section are observed and measured with the area per one viewing field being 62,500 ?m2 is 0.10 or less; and in a region from the surface to one-fifth of the radius and a region from the center to one-fifth of the radius in the transverse cross section, the amount of Al precipitating as AlN is 0.005% or less, and the density in terms of the number of AlN having a diameter of 100 nm or larger is 5/100 ?m2 or less.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: July 23, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Yoshihiro Daitoh, Akira Kito, Takayuki Nakamura
  • Patent number: 8486205
    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: 0.05 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 (% in terms of % by weight).
    Type: Grant
    Filed: August 16, 2011
    Date of Patent: July 16, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Motoo Satou, Tetsuo Soshiroda
  • Publication number: 20130174945
    Abstract: The present invention provides bearing steel, comprising a chemical composition including by mass %, C: 0.56%?[% C]?0.70%, Si: 0.15%?[% Si]<0.50%, Mn: 0.60%?[% Mn]?1.50%, Cr: 0.50%?[% Cr]?1.10%, Mo: 0.05%?[% Mo]?0.5%, P: [% P]?0.025%, S: [% S]?0.025%, Al: 0.005%?[% Al]?0.500%, O: [% O]?0.0015%, N: 0.0030%?[% N]?0.015%, and remainder as Fe and incidental impurities.
    Type: Application
    Filed: May 24, 2011
    Publication date: July 11, 2013
    Applicants: NTN CORPORATION, JFE STEEL CORPORATION
    Inventors: Minoru Honjo, Kazukuni Hase, Tatsumi Kimura, Shinji Mitao
  • Patent number: 8480821
    Abstract: A piston ring material is provided which retains excellent mechanical properties and processability, which are required of piston ring materials, and has wearing resistance and scuffing resistance, which are sliding properties required of piston rings. The piston ring material, which is for use in internal combustion engines, contains, in terms of mass %, 0.3-0.8% carbon, 0.1-3.0% silicon, 0.1-3.0% manganese, 0.01-0.3% sulfur, 0.1-2.0% chromium, and 0.05-2.0% the sum of titanium and/or zirconium, with the remainder being iron and incidental impurities. The titanium and/or zirconium contained in the piston ring material and the sulfur contained therein satisfy the following relationship. [Ti (%)+½Zr (%)]/S (%)?5.0 Preferably, the material may contain one or more members selected from up to 1.0% copper, less than 3.0% molybdenum, up to 1.0% aluminum, and less than 2.0% nickel, in terms of mass %.
    Type: Grant
    Filed: March 17, 2009
    Date of Patent: July 9, 2013
    Assignee: Hitachi Metals Ltd.
    Inventors: Katsuhiko Ohishi, Toshihiro Uehara, Kunichika Kubota
  • Publication number: 20130167983
    Abstract: The invention relates to a super bainite steel consisting of the following elements in weight %: C: 0.4-1.1 Mn: 0.4-2.1 Si: 0.15-1.2 Al: 0.0-2.0 Cr: 0.0-1.4 Ni: 0.0-2.5 Mo: 0.0-0.6 V: 0.0-0.3 Co: 0.0-3.0 P: <0.025 S: <0.025 the balance being iron and unavoidable impurities. The invention also relates to a method for manufacturing such a super bainite steel.
    Type: Application
    Filed: September 9, 2011
    Publication date: July 4, 2013
    Applicant: TATA STEEL UK LIMITED
    Inventors: Richard Clarke, Paul Davies, John Madill, Andrew James Rose, Andrew Smith, Alun Thomas
  • Patent number: 8470099
    Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.
    Type: Grant
    Filed: October 19, 2010
    Date of Patent: June 25, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Shingo Yamasaki, Toshiyuki Manabe, Daisuke Hirakami, Nariyasu Muroga
  • Patent number: 8465600
    Abstract: According to the present invention, there is provided a high strength steel sheet, which has, for example, a tensile strength of 590 to 980 MPa or more, which has favorable workability, and which is useful for an automobile, etc. The high strength steel sheet of the present invention comprises 0.03 to 0.20% C (% by mass in chemical compositions; hereafter, the same holds true), 0.50 to 2.5% Si, 0.50 to 2.5% Mn, and further, preferably 0.02 to 0.2% Mo. Moreover, its metal structure includes ferrite and low temperature transformation phase. The mean grain size of the low temperature transformation phase is 3.0 ?m or less. Further, grains whose size is 3.0 ?m or less occupy 50% or more by area ratio of the low temperature transformation phase, and an average aspect ratio of the low temperature transformation phase is 0.35 or more.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: June 18, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Seiko Watanabe, Masaaki Miura
  • 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: 8430977
    Abstract: The present invention relates to a hollow drilling steel rod including a stem portion and a thread portion positioned at an end portion in an axial direction with respect to the stem portion, the hollow drilling steel rod being constituted of a steel having a specific composition described in the present specification, in which the thread portion includes a thread having been subjected to a high frequency quenching, and the thread portion and the stem portion separate from each other have been joined by a friction welding.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: April 30, 2013
    Assignee: Mitsubishi Materials Corporation
    Inventors: Masaya Hisada, Yoneo Hiwasa, Satoshi Nagase, Noritaka Takahata
  • Publication number: 20130098515
    Abstract: A multi-phase hot-rolled steel sheet having improved strength in an intermediate strain rate region has a chemical composition comprising, in mass percent, C: 0.07-0.2%, Si+Al: 0.3-1.5%, Mn: 1.0-3.0%, P: at most 0.02%, S: at most 0.005%, Cr: 0.1-0.5%, N: 0.001-0.008%, at least one of Ti: 0.002-0.05% and Nb: 0.002-0.05%, and a remainder of Fe and impurities. The area fraction of ferrite is 7-35%, the grain diameter of ferrite is in the range of 0.5-3.0 ?m, and the nanohardness of ferrite is in the range of 3.5-4.5 GPa. A second phase which is the remainder other than ferrite contains martensite and bainitic ferrite and/or bainite. The average nanohardness of the second phase is 5-12 GPa, and the second phase contains a high-hardness phase of 8-12 GPa with an area fraction of 5-35% based on the overall structure.
    Type: Application
    Filed: April 7, 2011
    Publication date: April 25, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yasuaki Tanaka, Toshiro Tomida, Kaori Kawano
  • Publication number: 20130098513
    Abstract: This invention relates to an ultra-high-strength steel bar and to a method of manufacturing the same, in which the steel bar includes C: 0.05 to 0.45 wt %, Si: 0.10 to 0.35 wt %, Mn: 0.1 to 0.85 wt %, Cr: 0.6 to 1.20 wt %, and Mo: 0.05 to 0.35 wt %, with the remainder being Fe, wherein a martensite structure is formed at a surface layer and a fine ferrite structure is formed at a center layer.
    Type: Application
    Filed: April 18, 2011
    Publication date: April 25, 2013
    Applicant: HYUNDAI STEEL COMPANY
    Inventors: Sang-Youn Lee, Hyoung-Chul Lee, Yeong-Jun Kwon
  • Publication number: 20130087250
    Abstract: The present invention provides a steel for nitriding with a composition including, by mass %: C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 2.0%; Cr: 0.2% to 2.5%; Al: 0.01% to less than 0.19%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.001% to 0.01%; P limited to not more than 0.05%; S limited to not less than 0.2%; and a balance including Fe and inevitable impurities, the composition satisfying 2?[V]/[C]?10, where [V] is an amount of V by mass % and [C] is an amount of C by mass %, in which the steel for nitriding has a microstructure containing bainite of 50% or more in terms of an area percentage.
    Type: Application
    Filed: November 17, 2011
    Publication date: April 11, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tetsushi Chida, Manabu Kubota, Toshimi Tarui, Daisuke Hirakami, Masayuki Hashimura