Nickel Containing Patents (Class 148/335)
  • Patent number: 10500817
    Abstract: A steel for electron-beam welding according to the present invention includes at least C: 0.02% to 0.10%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, and O: 0.0010% to 0.0035%, further includes S: limited to 0.010% or less, P: limited to 0.015% or less, and Al: limited to 0.004% or less, with a balance including iron and inevitable impurities. An index value CeEBB obtained by substituting composition of the steel into following Formula 1 falls in the range of 0.42 to 0.65%, the number of oxide having an equivalent circle diameter of 1.0 ?m or more is 20 pieces/mm2 or less at a thickness center portion in cross section along the thickness direction of the steel, and the number of oxide containing Ti of 10% or more and having an equivalent circle diameter of not less than 0.05 ?m or more and less than 0.5 ?m falls in the range of 1×103 to 1×105 pieces/mm2 at the thickness center portion.
    Type: Grant
    Filed: October 27, 2011
    Date of Patent: December 10, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Ryuichi Honma, Ryuji Uemori, Tadashi Ishikawa, Akihiko Kojima, Manabu Hoshino
  • Patent number: 10428410
    Abstract: Steel alloys having high yield and ultimate tensile strengths in combination with high toughness based on medium carbon secondary hardening steel compositions having low cobalt content. Nickel is added to the medium carbon secondary hardening steel compositions to increase the yield and tensile strengths and fracture toughness. Applications of a steel alloy of the present disclosure include structural applications requiring high strength and high fracture toughness, such as aircraft landing gear.
    Type: Grant
    Filed: April 22, 2016
    Date of Patent: October 1, 2019
    Assignee: Carnegie Mellon University
    Inventor: Warren M. Garrison, Jr.
  • Patent number: 10147717
    Abstract: In the disclosure, an electrostatic discharge (ESD) protection circuit is coupled between a first power rail and a second power rail to discharge any ESD stress. The ESD protection circuit includes a detection circuit, a triggering circuit, and a dual silicon controlled rectifier (DSCR) device. When an ESD stresses is being applied to the first or second power rail, the detection circuit may first detect the ESD stresses and output a detection signal to the triggering circuit. The triggering circuit generates a triggering signal based on the detection signal and the polarity of the ESD stress. Then, the DSCR device is symmetrically triggered based on the triggering signal received at a common node between at least two transistors of the same type. The exemplary ESD protection circuit may be implemented in nanoscale manufactured integrated circuit and achieve good ESD robustness while maintaining low standby leakage current and relatively small silicon footprint.
    Type: Grant
    Filed: August 26, 2016
    Date of Patent: December 4, 2018
    Assignee: Novatek Microelectronics Corp.
    Inventors: Federico Agustin Altolaguirre, Ming-Dou Ker, Tzu-Chien Tzeng, Ju-Lin Huang
  • Patent number: 9951404
    Abstract: One aspect of the present disclosure is directed to low-alloy steels exhibiting high hardness and an advantageous level of multi-hit ballistic resistance with minimal crack propagation imparting a level of ballistic performance suitable for military armor applications. Certain embodiments of the steels according to the present disclosure have hardness in excess of 550 HBN and demonstrate a high level of ballistic penetration resistance relative to conventional military specifications.
    Type: Grant
    Filed: July 21, 2015
    Date of Patent: April 24, 2018
    Assignee: ATI PROPERTIES LLC
    Inventors: Ronald E. Bailey, Thomas R. Parayil, Glenn J. Swiatek
  • Patent number: 9945014
    Abstract: A high-manganese wear-resistant steel having excellent weldability comprises 5 to 15 wt % of Mn, 16?33.5C+Mn?30 of C, 0.05 to 1.0 wt % of Si, and a balance of Fe and other inevitable impurities. The microstructure thereof includes martensite as a major component, and 5% to 40% of residual austenite by area fraction.
    Type: Grant
    Filed: December 28, 2012
    Date of Patent: April 17, 2018
    Assignee: POSCO
    Inventors: Soon-Gi Lee, In-Shik Suh, In-Gyu Park, Hong-Ju Lee
  • Patent number: 9752203
    Abstract: The present invention describes a process to make enhanced fatigue strength micro-alloy steel. In the process of the present invention, the soaking temperature is maintained in the range of 900° C. to 1050° C. and soaking time in the range of 30-60 minutes depending on size of crankshaft to get refined grain size. Distortion of the components is prevented from occurring with provision of adequate supports especially designed for the process. Forged parts made using the process, such as crankshafts, have a refined grain pattern and result into 20 to 25% enhancement in torsion fatigue strength & 10-25% enhancement in bending fatigue strength. The present invention thus provides an enhanced ratio of the strength to material density and a micro-alloy whose torsion fatigue strength and bending fatigue strength are greater than the currently available micro-alloy steels.
    Type: Grant
    Filed: October 3, 2012
    Date of Patent: September 5, 2017
    Inventor: Babasaheb Neelkanth Kalyani
  • Patent number: 9034121
    Abstract: A low alloy steel ingot contains from 0.15 to 0.30% of C, from 0.03 to 0.2% of Si, from 0.5 to 2.0% of Mn, from 0.1 to 1.3% of Ni, from 1.5 to 3.5% of Cr, from 0.1 to 1.0% of Mo, and more than 0.15 to 0.35% of V, and optionally Ni, with a balance being Fe and unavoidable impurities. Performing quality heat treatment including a quenching step and a tempering step to the low alloy steel ingot to obtain a material, which has a grain size number of from 3 to 7 and is free from pro-eutectoid ferrite in a metallographic structure thereof, and which has a tensile strength of from 760 to 860 MPa and a fracture appearance transition temperature of not higher than 40° C.
    Type: Grant
    Filed: April 17, 2012
    Date of Patent: May 19, 2015
    Assignees: THE JAPAN STEEL WORKS,LTD., KABUSHIKI KAISHA TOSHIBA
    Inventors: Satoru Ohsaki, Kazuhiro Miki, Tsukasa Azuma, Koji Kajikawa, Shigeru Suzuki, Masayuki Yamada, Itaru Murakami, Kenichi Okuno, Liang Yan, Reki Takaku, Akihiro Taniguchi, Tetsuya Yamanaka, Makoto Takahashi, Kenichi Imai, Osamu Watanabe, Joji Kaneko
  • Patent number: 9034120
    Abstract: Provided is bearing steel excellent in workability after spheroidizing-annealing and in hydrogen fatigue resistance property after quenching and tempering. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; and 0.0020% or less O, which further contains more than 0.0015% to 0.0050% or less Sb, with the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the roiling contact fatigue life and also the workability such as cuttability and forgeability of the material.
    Type: Grant
    Filed: November 29, 2011
    Date of Patent: May 19, 2015
    Assignee: JFE STEEL CORPORATION
    Inventors: Yasumasa Hirai, Kiyoshi Uwai
  • Patent number: 9005520
    Abstract: The invention concerns steels having excellent resistance over time, in a corrosive atmosphere due to oxidizing environments such as, for example, fumes or water vapor, under high pressure and/or temperature. The invention concerns a steel composition for special applications, said composition containing, by weight, about 1.8 to 11% of chromium (and preferably between about 2.3 and 10% of chromium), less than 1% of silicon, and between 0.20 and 0.45% of manganese. It has been found that it is possible to adjust the contents of the composition based on a predetermined model, selected to obtain substantially optimal properties with respect to corrosion in specific conditions of high temperature performances. Said model can involve as additive of as residue at least one element selected among molybdenum, tungsten, cobalt, and nickel.
    Type: Grant
    Filed: June 7, 2007
    Date of Patent: April 14, 2015
    Assignees: V & M France
    Inventors: Jean Leyer, Bruno Vandenberghe, Viviane Lepingle, Ghislain Louis, Annie Fouquet, Catheline Petelot, Emilie Petelot, Adeline Petelot
  • Patent number: 8999078
    Abstract: A forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.
    Type: Grant
    Filed: December 23, 2011
    Date of Patent: April 7, 2015
    Assignees: Kabushiki Kaisha Toshiba, The Japan Steel Works, Ltd.
    Inventors: Masayuki Yamada, Reki Takaku, Haruki Ohnishi, Kenichi Okuno, Kenichi Imai, Kazuhiro Miki, Tsukasa Azuma, Satoru Ohsaki
  • Patent number: 8992698
    Abstract: Provided is a welding metal in which the chemical component composition thereof is appropriately controlled; an A value that is specified by a predetermined relational expression satisfies the requirement of being 3.8% to 9.0%; an X value that is specified by a predetermined relational expression satisfies the requirement of being 0.5% or greater; the area percentage of carbide particles having a circle-equivalent diameter of 0.20 ?m or greater in the welding metal is 4.0% or less; and the number of carbide particles having a circle-equivalent diameter of 1.0 ?m or greater is 1000 particles/mm2 or less. This welding metal, which can exhibit not only high strength but also good low-temperature toughness and good drop-weight characteristics, is useful as a material for a pressure vessel in a nuclear power plant.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: March 31, 2015
    Assignee: Kobe Steel. Ltd.
    Inventors: Hidenori Nako, Yoshitomi Okazaki, Ken Yamashita, Minoru Otsu, Hideaki Takauchi
  • Patent number: 8992697
    Abstract: A high strength press-formed member includes a steel sheet constituting the member including a composition including by mass %, C: 0.12% to 0.69%, Si: 3.0% or less, Mn: 0.5% to 3.0%, P: 0.1% or less, S: 0.07% or less, Al: 3.0% or less, N: 0.010% or less, Si+Al: at least 0.
    Type: Grant
    Filed: February 28, 2011
    Date of Patent: March 31, 2015
    Assignee: JFE Steel Corporation
    Inventors: Hiroshi Matsuda, Yoshimasa Funakawa, Yasushi Tanaka
  • Publication number: 20150083282
    Abstract: There is provided a seamless steel pipe having high strength and high toughness even if having a thick wall. A seamless steel pipe according to the present embodiment consists of: in mass %, C: 0.03 to 0.08%, Si: not more than 0.25%, Mn: 0.3 to 2.0%, P: not more than 0.05%, S: not more than 0.005%, Al: 0.001 to 0.10%, Cr: 0.02 to 1.0%, Ni: 0.02 to 1.0%, Mo: 0.02 to 0.8%, N: 0.002 to 0.008%, Ca: 0.0005 to 0.005%, and Nb: 0.01 to 0.1%, the balance being Fe and impurities, and has a wall thickness of not less than 50 mm.
    Type: Application
    Filed: April 10, 2013
    Publication date: March 26, 2015
    Inventors: Yukimasa Ueda, Yuji Arai
  • Patent number: 8980022
    Abstract: This case hardening steel has a chemical composition including, by mass %: C: 0.1 to 0.6%; Si: 0.02 to 1.5%; Mn: 0.3 to 1.8%; P: 0.025% or less; S: 0.001 to 0.15%; Al: over 0.05 to 1.0%; Ti: 0.05 to 0.2%; N: 0.01% or less; and O: 0.0025% or less, and further including, by mass %, one or more of Cr: 0.4 to 2.0%, Mo: 0.02 to 1.5%, Ni: 0.1 to 3.5%, V: 0.02 to 0.5%, and B: 0.0002 to 0.005%, and the balance consisting of iron and unavoidable impurities.
    Type: Grant
    Filed: January 13, 2010
    Date of Patent: March 17, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kei Miyanishi, Masayuki Hashimura, Shuuji Kozawa, Manabu Kubota, Tatsuro Ochi
  • Patent number: 8980019
    Abstract: A steel rail includes: by mass %, higher than 0.85% to 1.20% of C; 0.05% to 2.00% of Si; 0.05% to 0.50% of Mn; 0.05% to 0.60% of Cr; P?0.0150%; and the balance consisting of Fe and inevitable impurities, wherein 97% or more of a head surface portion which is in a range from a surface of a head corner portion and a head top portion as a starting point to a depth of 10 mm has a pearlite structure, a Vickers hardness of the pearlite structure is Hv320 to 500, and a CMn/FMn value which is a value obtained by dividing CMn [at. %] that is a Mn concentration of a cementite phase in the pearlite structure by FMn [at. %] that is a Mn concentration of a ferrite phase is equal to or higher than 1.0 and equal to or less than 5.0.
    Type: Grant
    Filed: June 7, 2011
    Date of Patent: March 17, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Masaharu Ueda, Jun Takahashi, Akira Kobayashi, Takuya Tanahashi
  • Patent number: 8974610
    Abstract: A high-strength welded steel pipe is obtained by welding a seam weld portion of a steel plate that are formed in a pipe shape. In the high-strength welded steel pipe, a base metal of the steel plate includes, by mass %, C: 0.010% to 0.080%, Si: 0.01% to 0.50%, Mn: 0.50% to 2.00%, S: 0.0001% to 0.0050%, Ti: 0.003% to 0.030%, Mo: 0.05% to 1.00%, B: 0.0003% to 0.0100%, O: 0.0001% to 0.0080%, N: 0.006% to 0.0118%, P: limited to 0.050% or less, Al: limited to 0.008% or less, and the balance of Fe and inevitable impurities, Ceq is 0.30 to 0.53, Pcm is 0.10 to 0.20, [N]?[Ti]/3.4 is less than 0.003, the average grain size of the prior ? grains in heat affected zones in the steel plate is 250 ?m or less, and the prior ? grains include bainite and intragranular bainite.
    Type: Grant
    Filed: February 4, 2011
    Date of Patent: March 10, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Taishi Fujishiro, Takuya Hara, Yoshio Terada, Shinya Sakamoto, Hitoshi Asahi
  • Publication number: 20150059912
    Abstract: A steel plate has a chemical composition containing, by mass %, C: 0.03% or more and 0.08% or less, Si: 0.01% or more and 1.0% or less, Mn: 1.2% or more and 3.0% or less, P: 0.015% or less, S: 0.005% or less, Al: 0.08% or less, Nb: 0.005% or more and 0.07% or less, Ti: 0.005% or more and 0.025% or less, N: 0.010% or less, O: 0.005% or less and the balance being Fe and inevitable impurities, a metallographic structure including a bainite phase and island martensite, and a polygonal ferrite in surface portions within 5 mm from the upper and lower surfaces, wherein the area fraction of the island martensite is 3% to 15%, the equivalent circle diameter of the island martensite is 3.0 ?m or less, the area fraction of the polygonal ferrite in the surface portions is 10% to less than 80%.
    Type: Application
    Filed: March 29, 2013
    Publication date: March 5, 2015
    Inventors: Junji Shimamura, Kimihiro Nishimura
  • Patent number: 8961710
    Abstract: A carburized component with improved fatigue strength has a base steel containing, by mass %, C: 0.15-0.25%, Si: 0.03-0.50%, Mn: more than 0.60% and not more than 1.5%, P?0.015%, S: 0.006-0.030%, Cr: 0.05-2.0%, Al?0.10%, N?0.03%, and O?0.0020%, and optionally at least one element selected from Mo, Cu, Ni, B, Ti, Nb and V, the balance being Fe and impurities. A surface hardened layer portion satisfies: (a) average carbon concentration in the region from the outermost surface to a point of 0.2 mm depth of 0.35-0.60 mass %, (b) surface roughness Rz?15 ?m, and (c) ?r(0)??800 MPa, ?r(100)??800 MPa, and residual stress intensity index Ir?80000, wherein Ir is calculated by [Ir=?|?r(y)|dy], where y ?m is the depth from the outermost surface and ?r(y) is the residual stress for the points from the outermost surface to a depth of 100 ?m with the range of y from 0 to 100 (?m).
    Type: Grant
    Filed: November 28, 2011
    Date of Patent: February 24, 2015
    Assignees: Nippon Steel & Sumitomo Metal Corporation, Sintokogio, Ltd.
    Inventors: Yutaka Neishi, Takanari Hamada, Hidekazu Sueno, Yuji Kobayashi, Hideaki Sugiura
  • Patent number: 8956470
    Abstract: A steel (known as super bainite steel) containing between 90% and 50% bainite, the rest being austenite, in which excess carbon remains within the bainitic ferrite at a concentration beyond that consistent with equilibrium; there is also partial partitioning of carbon into the residual austenite. In one embodiment of the disclosure, the steel contains in weight percent: carbon 0.6 to 1.1%, silicon 1.5 to 2.0%, manganese 0.5 to 1.8, nickel up to 3%, chromium 1.0 to 1.5, molybdenum 0.2 to 0.5%, vanadium 0.1 to 0.2%, balance iron save for incidental impurities. Excellent properties are obtained if the manganese content is about 1% by weight.
    Type: Grant
    Filed: July 31, 2009
    Date of Patent: February 17, 2015
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: Harshad Kumar Dharamshi Hansraj Bhadeshia, Carlos Garcia-Mateo, Peter Brown
  • Patent number: 8951366
    Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.
    Type: Grant
    Filed: January 26, 2011
    Date of Patent: February 10, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
  • Patent number: 8951367
    Abstract: A cold rolled steel sheet with excellent bendability contains C at 0.15 to 0.30%, Si at 0.01 to 1.8%, Mn at 1.5 to 3.0%, P at not more than 0.05%, S at not more than 0.005%, Al at 0.005 to 0.05% and N at not more than 0.005%, the balance being Fe and inevitable impurities, and has a steel sheet superficial soft portion satisfying: Hv(S)/Hv(C)?0.8??(1) wherein Hv(S) is hardness of the steel sheet superficial soft portion, and Hv(C) is hardness of a steel sheet core portion, 0.10?t(S)/t?0.30??(2) wherein t(S) is thickness of the steel sheet superficial soft portion, and t is the sheet thickness.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: February 10, 2015
    Assignee: JFE Steel Corporation
    Inventors: Kenji Kawamura, Kazuhiro Seto
  • Patent number: 8932414
    Abstract: Disclosed is a high-strength steel plate with excellent warm workability that has a component composition comprising, in mass %, 0.05 to 0.4% C, 0.5 to 3% Si+Al, 0.5 to 3% Mn, no more than 0.15% P (not including 0%), and no more than 0.02% S (including 0%), with the remainder comprising iron and impurities, and a composition that includes a total of 45 to 80% martensite and/or bainitic ferrite in terms of the area ratio relative to the entire composition, 5 to 40% polygonal ferrite in terms of the area ratio relative to the entire composition, and 5 to 20% retained austenite in terms of the area ratio relative to the entire composition, wherein the C concentration (C?R) within said residual austenite is in the range of 0.6 mass % to less than 1.0 mass %, and that furthermore may include bainite. In the high-strength steel plate, TRIP effects are achieved to the fullest extent in warm working, and increased ductility over prior steel plates is reliably achieved.
    Type: Grant
    Filed: March 22, 2011
    Date of Patent: January 13, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Hideo Hata, Toshio Murakami, Yukihiro Utsumi
  • Patent number: 8932415
    Abstract: Provided is a welding metal in which a predetermined chemical component composition is satisfied, the A value as specified by formula (1) is 3.8% to 9.0%, and the surface area percentage of carbide having a circle-equivalent diameter of 0.20 ?m or greater in the welding metal is 4.0% or less. A value=0.8×[C]?0.05×[Si]+0.5×[Mn]+0.5×[Cu]+[Ni]?0.5×[Mo]+0.2×[Cr]??(1) (Provided that [C], [Si], [Mn], [Cu], [Ni], [Mo] and [Cr] are the C, Si, Mn, Cu, Ni, Mo and Cr content (by mass percent), respectively) The welding metal is useful as a material for a pressure vessel of a nuclear power plant as the welding metal is high in strength and has good low-temperature toughness and drop-weight characteristics.
    Type: Grant
    Filed: January 24, 2011
    Date of Patent: January 13, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Hidenori Nako, Yoshitomi Okazaki, Ken Yamashita, Minoru Otsu, Hideaki Takauchi
  • Publication number: 20150004433
    Abstract: A steel sheet includes, by mass %: C: 0.020% to 0.080%; Si: 0.01% to 0.10%; Mn: 0.80% to 1.80%; and Al: more than 0.10% and less than 0.40%; and further includes: Nb: 0.005% to 0.095%; and Ti: 0.005% to 0.095%, in which a total amount of Nb and Ti is 0.030% to 0.100%, and the steel sheet includes, as a metallographic structure, ferrite, bainite, and other phases, an area fraction of the ferrite is 80% to 95%, an area fraction of the bainite is 5% to 20%, a total fraction of the other phases is less than 3%, a tensile strength is 590 MPa or more, and a fatigue strength ratio as a fatigue strength to the tensile strength is 0.45 or more.
    Type: Application
    Filed: February 7, 2013
    Publication date: January 1, 2015
    Inventors: Hiroyuki Tanaka, Kunio Hayashi, Toshio Ogawa, Koichi Goto, Kazuaki Nakano
  • Patent number: 8920583
    Abstract: The invention provides a steel pipe excellent in deformation characteristics, most notably a steel pipe for expandable-pipe oil well and a low-yield-ratio line pipe, and a method of producing the same without conducting water cooling requiring large-scale heat treatment equipment, namely a method of producing a steel pipe excellent in deformation characteristics whose microstructure is a two-phase structure including a martensite-austenite constituent at an area fraction of 2 to 10% and a soft phase, which method comprises: heating at Ac1+10° C. to Ac1+60° C. and thereafter cooling a precursor steel pipe which contains, in mass %, C: 0.04 to 0.10% and Mn: 1.00 to 2.50%, is limited to Si: 0.80% or less, P: 0.03% or less, S: 0.01% or less, Al: 0.10% or less and N: 0.01% or less, further contains one or more of Ni: 1.00% or less, Mo: 0.60% or less, Cr: 1.00% or less and Cu: 1.00% or less, where content of Mn and content of one or more of Cr, Ni, Mo and Cu satisfy Mn+Cr+Ni+2Mo+Cu?2.
    Type: Grant
    Filed: July 22, 2008
    Date of Patent: December 30, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Hitoshi Asahi, Tetsuo Ishitsuka, Motofumi Koyuba, Toshiyuki Ogata
  • Patent number: 8920582
    Abstract: A steel material which is suitable for hot press working or hot three-dimensional bending and direct quench and which can be used to manufacture a high-strength formed article with sufficient quench hardening even by short time heating at a low temperature has a chemical composition comprising, in mass percent, C: 0.05-0.35%, Si: at most 0.5%, Mn: 0.5-2.5%, P: at most 0.03%, S: at most 0.01%, sol. Al: at most 0.1%, N: at most 0.01%, and optionally at least one element selected from the group consisting of B: 0.0001-0.005%, Ti: 0.01-0.1%, Cr: 0.18-0.5%, Nb: 0.03-0.1%, Ni: 0.18-1.0%, and Mo: 0.03-0.5% and has a steel structure in which the spheroidization ratio of carbides is 0.60-0.90.
    Type: Grant
    Filed: August 22, 2012
    Date of Patent: December 30, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kazuo Hikita, Nobusato Kojima
  • Patent number: 8911567
    Abstract: The high-strength steel sheet includes, by mass %: C: 0.01% to 0.10%; Si: 0.15% or less; Mn: 0.80% to 1.80%; P: 0.10% or less; S: 0.015% or less; Al: 0.10% to 0.80%; Cr: 0.01% to 1.50%; N: 0.0100% or less; and a balance consisting of iron and inevitable impurities, in which a metallic structure is composed of ferrite and a hard second phase, the area fraction of the ferrite is 80% or more, the area fraction of the hard second phase is 1% to 20%, the fraction of unrecrystallized ferrite in the ferrite is less than 10%, the ferrite grain sizes are 5 ?m to 20 ?m, and the fraction of the ferrite crystal grains having an aspect ratio of 1.2 or less in the entire ferrite crystal grains is 60% or more.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: December 16, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Toshio Ogawa, Naoki Matsutani, Koichi Goto, Shinichiro Watanabe, Nobuhiro Fujita, Toshiki Nonaka
  • Patent number: 8899094
    Abstract: The present invention is typically embodied as a method for studying ballistic resistance of one or more steel materials. A projectile is caused to strike groups of steel samples made of the same steel material, and the ballistic limit V50 of each steel material is determined. Prior to the V50 testing, a sample of each steel material is metallographically imaged so as to reveal austenitic bodies therein. The austenitic volume fraction of a sample of each steel material is measured via VSM at least once prior to the V50 testing and at least once subsequent to the V50 testing. Subsequent to the V50 testing, a microhardness distribution is mapped characterizing a sample of each steel material in the vicinity of the ballistic crater. The empirical results are assessed in light of the inventively discovered mechanism of plasticity of the steel that is ballistically induced in relation to austenite-to-martensite transformation.
    Type: Grant
    Filed: April 10, 2012
    Date of Patent: December 2, 2014
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Xian Jie Zhang
  • Publication number: 20140345756
    Abstract: A reduced nickel-chromium alloy component having by weight about 0.38% to about 0.43% C, about 0.15% to about 0.30% Si, about 1.00% to about 1.25% Mn, about 0.75% to about 0.90% Ni, about 1.00% to about 1.30% Cr, about 0.25% to about 0.35% Mo, about 0.05% to about 0.12% V, up to about 0.015% S, up to about 0.015% P, up to about 0.15% Cu, and balance iron and incidental impurities. The component has a hardenability corresponding to an ideal diameter of greater than about 10 inches.
    Type: Application
    Filed: May 21, 2013
    Publication date: November 27, 2014
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Jeremy RIDGE, Ted F. MAJKA, John Randolph WOOD
  • Patent number: 8894779
    Abstract: Provided is bearing steel excellent in post spheroidizing-annealing workability and in post quenching-tempering hydrogen fatigue resistance property. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; 0.0020% or less O; and the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the rolling contact fatigue life and also the workability such as cuttability and forgeability of the material.
    Type: Grant
    Filed: November 24, 2011
    Date of Patent: November 25, 2014
    Assignee: JFE Steel Corporation
    Inventors: Yasumasa Hirai, Kiyoshi Uwai
  • Patent number: 8894778
    Abstract: The present invention relates to a mechanical part, which is obtained by: processing a steel into a shape of a part, the steel having an alloy composition containing, by weight percent, C: 0.10 to 0.30%, Si: 0.50 to 3.00%, Mn: 0.30 to 3.00%, P: 0.030% or less, S: 0.030% or less, Cu: 0.01 to 1.00%, Ni: 0.01 to 3.00%, Cr: 0.20 to 1.00%, Al: 0.20% or less, N: 0.05% or less, and the remainder of Fe and inevitable impurities, and the alloy composition satisfying the following condition: [Si %]+[Ni %]+[Cu %]?[Cr %]>0.50, in which [Si %], [Ni %], [Cu %] and [Cr %] represent the concentration of Si, the concentration of Ni, the concentration of Cu and the concentration of Cr in the alloy composition, respectively; subjecting the steel to a carburizing treatment in a vacuum, followed by gradually cooling the steel; and subsequently subjecting the steel to a high-frequency hardening to thereby harden a surface of the steel.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: November 25, 2014
    Assignees: Daido Tokushuko Kabushiki Kaisha, Aisin Aw Co., Ltd.
    Inventors: Toshiyuki Morita, Kouji Ohbayashi, Masaki Kuwabara, Taro Matsukawa, Yutaka Eto, Kohki Mizuno
  • Patent number: 8882938
    Abstract: A high strength hot dip galvanized steel strip including, in mass percent, of the following elements: 0.10-0.18% C, 1.90-2.50% Mn, 0.30-0.50% Si, 0.50-0.70% Al, 0.10-0.50% Cr, 0.001-0.10% P, 0.01-0.05% Nb, max 0.004% Ca, max 0.05% S, max 0.007% N, and optionally at least one of the following elements: 0.005-0.50% Ti, 0.005-0.50% V, 0.005-0.50% Mo, 0.005-0.50% Ni, 0.005-0.50% Cu, max 0.005% B, the balance Fe and inevitable impurities, wherein 0.80%<Al+Si<1.05% and Mn+Cr>2.10%. This steel offers improved formability at a high strength, has a good weldability and surface quality together with a good produce-ability and coat-ability.
    Type: Grant
    Filed: December 21, 2010
    Date of Patent: November 11, 2014
    Assignee: Tata Steel Ijmuiden B.V.
    Inventors: Bernard Leo Ennis, David Neal Hanlon
  • Patent number: 8882942
    Abstract: A Ni-added steel plate contains, by mass %, C: 0.03% to 0.10%, Si: 0.02% to 0.40%, Mn: 0.3% to 1.2%, Ni: 5.0% to 7.5%, Cr: 0.4% to 1.5%, Mo: 0.02% to 0.4%, Al: 0.01% to 0.08%, T.O: 0.0001% to 0.0050%, P: limited to 0.0100% or less, S: limited to 0.0035% or less, and N: limited to 0.0070% or less with a remainder composed of Fe and inevitable impurities, in which a Ni segregation ratio at a position of ¼ of a plate thickness away from a plate surface in a thickness direction is 1.3 or less, a fraction of austenite after deep cooling is 2% or more, an austenite unevenness index after deep cooling is 5.0 or less, and an average equivalent circle diameter of austenite after deep cooling is 1 ?m or less.
    Type: Grant
    Filed: July 7, 2011
    Date of Patent: November 11, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Hitoshi Furuya, Naoki Saitoh, Motohiro Okushima, Yasunori Takahashi, Takehiro Inoue, Ryuji Uemori
  • Patent number: 8876987
    Abstract: A high strength pressed member has excellent ductility and stretch flangeability and tensile strength of 780-1400 MPa, with a predetermined steel composition and steel microstructure relative to the entire microstructure of steel sheet, where area ratio of martensite 5-70%, area ratio of retained austenite 5-40%, area ratio of bainitic ferrite in upper bainite 5% or more, and total thereof is 40% or more, 25% or more of martensite is tempered martensite, polygonal ferrite area ratio is above 10% and below 50% to the entire microstructure of steel sheet, and average grain size is 8 ?m or less, average diameter of a group of polygonal ferrite grains is 15 ?m or less, the group of polygonal ferrite grains represented by a group of ferrite grains of adjacent polygonal ferrite grains, and average carbon content in retained austenite is 0.70 mass % or more and tensile strength is 780 MPa or more.
    Type: Grant
    Filed: October 2, 2012
    Date of Patent: November 4, 2014
    Assignee: JFE Steel Corporation
    Inventors: Hiroshi Matsuda, Yoshimasa Funakawa, Kaneharu Okuda, Kazuhiro Seto
  • Patent number: 8871039
    Abstract: The present invention provides a thick welded steel pipe excellent in low temperature toughness in which contents of Mn and Mo satisfy (Expression 1) below, Pcm obtained by (Expression 2) below is 0.16 to 0.19, and a metal structure of a base material steel plate consists of ferrite being 30 to 95% in an area ratio and a low temperature transformation structure, and in a metal structure of a coarse-grained HAZ, an area ratio of grain boundary ferrite is 1.5% or more, the total area ratio of the grain boundary ferrite and intragranular ferrite is not less than 11% nor more than 90%, an area ratio of MA is 10% or less, and its balance is composed of bainite. 1.2325?(0.85×[Mn]?[Mo])?1.5215??(Expression 1) and Pcm=[C]+[Si]/30+([Mn]+[Cu]+[Cr])/20+[Ni]/60+[Mo]/15+[V]/10??(Expression 2).
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: October 28, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Yasuhiro Shinohara, Takuya Hara, Naoki Doi, Eiichi Yamashita
  • Patent number: 8871040
    Abstract: The invention relates to an air hardenable high-hardness steel for armoring applications, such as armor plate for use in light armored vehicles and body armor, and having a high level of ballistic performance relative to its plate thickness. In particular, the invention concerns a high ballistic strength martensitic armor steel which, in an air cooled and untempered condition, has a strength coefficient (s0) of higher than 2500 MPa; a flow parameter (P) of higher than 8.0, preferably higher than 18.0; and a manganese content of 1.8 to 3.6% by weight of manganese, preferably 2.8 to 3.1% by weight of manganese. The armor steel also includes retained austenite at a volume fraction of at least 1%, and preferably a volume fraction of 4 to 20%.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: October 28, 2014
    Assignee: Damascus Armour Development (Pty) Ltd.
    Inventors: Deon Francoise Du Plessis, Jacob Johannes Wessels, Percy Phillip Adams, Roelof Johannes Mostert, Waldo Edmund Stumpf
  • 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
  • Publication number: 20140299237
    Abstract: The invention relates to a method for manufacturing a high-strength structural steel and to a high-strength structural steel product. The method comprises a providing step for providing a steel slab, a heating step (1) for heating said steel slab to 950 to 1300 C, a temperature equalizing step (2) for equalizing the temperature of the steel slab, a hot rolling step including a hot rolling stage of type I (5) for hot rolling the steel slab in the no-recrystallization temperature range below the recrystallization stop temperature (RST) but above the ferrite formation temperature A3, a quenching step (6) for quenching said hot-rolled steel at cooling rate of at least 20 C/s to a quenching-stop temperature (QT) between Ms and Mf temperatures, a partitioning treatment step (7, 9) for partitioning said hot-rolled steel in order to transfer carbon from martensite to austenite, and a cooling step (8) for cooling said hot-rolled steel to room temperature.
    Type: Application
    Filed: July 2, 2012
    Publication date: October 9, 2014
    Applicant: RAUTARUUKKI OYJ
    Inventors: Mahesh Chandra Somani, David Arthur Porter, Leo Pentti Karjalainen, Tero Tapio Rasmus, Ari Mikael Hirvi
  • Publication number: 20140299236
    Abstract: Disclosed herein are embodiments of a seamless quenched and tempered steel pipe which can have a wall thickness WT higher than or equal to 6 mm and lower than or equal to 35 mm. Some embodiments of the steel pipe can have a chemical composition comprising C, Mn, Si, Cr, Ni, Mo, Al, N, Ca, Nb, Ti, V, Zr, and Ta based on the composition weight, the remaining being iron and impurities. In some embodiments, wherein (V+Nb) content is lower than 0.07 wt %; defining a first parameter P1=(60×C)+Cr+[5×e(35×Mo/WT)]+50×(V+Nb), the chemical composition satisfies a first condition P1?14.5.
    Type: Application
    Filed: April 8, 2014
    Publication date: October 9, 2014
    Applicant: Dalmine S.p.A.
    Inventors: Ettore Anelli, Emanuele Paravicini Bagliani, Stefano Fare, José Enrique Garcia Gonzales, Victor Blancas Garcia, Héctor Manuel Quintanilla Carmona
  • Publication number: 20140299235
    Abstract: Disclosed herein are embodiments of a seamless quenched and tempered steel pipe having a wall thickness (WT) higher than or equal to 35 mm and lower than or equal to 80 mm. Embodiments of the steel pipe can comprise C, Mn, Cr, Ni, Mo, Al, Ca, N, Nb, Ti, Zr, and Ta. Further, for some embodiments of the steel pipe wherein, defining a first parameter P1=50×C+Cr+10×Mo+70×V, the chemical composition can satisfy a first condition P1?8.0.
    Type: Application
    Filed: April 8, 2014
    Publication date: October 9, 2014
    Applicant: Dalmine S.p.A.
    Inventors: Ettore Anelli, Emanuele Paravicini Bagliani, Stefano Fare
  • Publication number: 20140290807
    Abstract: A low yield ratio and high-strength hot rolled steel sheet having a composition containing, on a mass percent basis, 0.03% to 0.10% C, 0.10% to 0.50% Si, 1.4% to 2.2% Mn, 0.005 % to 0.10% Al, 0.02% to 0.10% Nb, 0.001% to 0.030% Ti, 0.05% to 0.50% Mo, 0.05% to 0.50% Cr, and 0.01% to 0.50% Ni, in which Moeq preferably satisfies the range of 1.4% to 2.2%; and a microstructure including a main phase that contains bainitic ferrite having an average grain size of 10 ?m or less and a secondary phase that contains massive martensite having an aspect ratio of less than 5.0 in an area ratio of 1.4% to 15%.
    Type: Application
    Filed: June 13, 2012
    Publication date: October 2, 2014
    Applicant: JFE Steel Corporation
    Inventors: Sota Goto, Hiroshi Nakata, Chikara Kami, Toshifumi Abe, Takato Tamai
  • Patent number: 8821653
    Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacturing thick walled pipes (wall thickness greater than or equal to about 35 mm) there from. In one embodiment, a steel composition is processed that yields an average prior austenite grain size greater than about 15 or 20 ?m and smaller than about 100 ?m. Using this composition, a quenching sequence is provided that yields a microstructure of greater than or equal to about 50% by volume, and less than or equal to about 50% by volume, lower bainite, without substantial ferrite, upper bainite, or granular bainite. After quenching, pipes may be tempered. The quenched and tempered pipes may exhibit yield strengths greater than about 450 MPa (65 ksi) or 485 (70 ksi). Mechanical property measurements find the quenched and tempered pipes suitable for 450 MPa grade and 485 MPa grade, and resistance to sulfide stress corrosion cracking.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: September 2, 2014
    Assignee: Dalmine S.p.A.
    Inventors: Ettore Anelli, Mariano Armengol, Paolo Novelli, Federico Tintori
  • 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
  • Patent number: 8815024
    Abstract: The present invention provides steel plate or steel pipe with small occurrence of the Bauschinger effect and methods of production of the same, particularly steel pipe used for steel pipe for oil wells or line pipe with a small drop in the compression strength in the circumferential direction due to the Bauschinger effect when expanded and methods of production of the same, that is steel plate or steel pipe with small occurrence of the Bauschinger effect characterized by having a dual-phase structure substantially comprising a ferrite structure and fine martensite which is dispersed in the ferrite structure. Further, this steel plate or steel pipe contains, by mass %, C: 0.03 to 0.30%, Si: 0.01 to 0.8%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.001 to 0.01%, and N: 0.01% or less and a balance of iron and unavoidable impurities.
    Type: Grant
    Filed: February 15, 2005
    Date of Patent: August 26, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Hitoshi Asahi, Eiji Tsuru
  • Patent number: 8815147
    Abstract: A cold die steel excellent in the characteristic of suppressing dimensional change, which has a chemical composition in mass %: C: 0.7% or more and less than 1.6%, Si: 0.5 to 3.0%, Mn: 0.1 to 3.0%, P: less than 0.05% including 0%, S: 0.01 to 0.12%, Cr: 7.0 to 13.0%, one or two elements selected from the group consisting of Mo and W: amounts satisfying the formula (Mo+(W/2))=0.5 to 1.7%, V: less than 0.7% including 0, Ni: 0.3 to 1.5%, Cu: 0.1 to 1.0% and Al: 0.1 to 0.7%. Preferably, the die steel satisfies the formula in mass %: Ni/Al=1 to 3.7. It is preferred that the die steel also satisfies the following formula in mass %: (Cr?4.2×C)=5 or less and (Cr?6.3×C)=1.4 or more and that it contains 0.3% or less of Nb.
    Type: Grant
    Filed: December 24, 2008
    Date of Patent: August 26, 2014
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kunichika Kubota, Hideshi Nakatsu, Shugo Komatsubara
  • 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
  • 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
  • Patent number: 8747578
    Abstract: A steel having excellent formability, fatigue endurance after quenching, low temperature toughness, resistance for hydrogen embrittlement, and corrosion fatigue endurance. A method includes heating a steel slab at 1160° C. to 1320° C., hot-finish-rolling the steel slab at a finisher delivery temperature of 750° C. to 980° C., and then coiling the hot-rolled steel at a coiling temperature of 560° C. to 740° C. after slow cooling for a time of 2 seconds or more to produce a hot-rolled steel strip having a structure in which the ferrite grain diameter df corresponding to a circle is 1.1 ?m to less than 1.2 ?m and the ferrite volume fraction Vf is 30% to 98%, the steel slab containing 0.18 to 0.29% of C, 0.06 to 0.45% of Si, 0.91 to 1.85% of Mn, 0.019% or less of P, 0.0029% or less of S, 0.015 to 0.075% of sol. Al, 0.0049% or less of N, 0.0049% or less of O, 0.0001 to 0.0029% of B, 0.001 to 0.019% of Nb, 0.001 to 0.029% of Ti, 0.001 to 0.195% of Cr, and 0.001 to 0.
    Type: Grant
    Filed: December 9, 2004
    Date of Patent: June 10, 2014
    Assignees: JFE Steel Corporation, Toyota Jidosha Kabushiki Kaisha
    Inventors: Shunsuke Toyoda, Kei Sakata, Akio Sato, Kouichi Kaneko, Hiroshi Kawaguchi
  • Patent number: 8747574
    Abstract: Provided is a maraging steel strip which has such a composition that can reduce the content of TiN acting as the starting point of fatigue fracture in a high-cycle region, and the bending fatigue strength of which has been improved by the precipitation hardening effect yielded by precipitating coherent nitrides in the nitrided structure. A maraging steel strip produced by nitriding a managing steel which contains by mass, C: 0.01% or less, Si: 0.1% or less, Mn: 0.1% or less, P: 0.01% or less, S: 0.005% or less, Ni: 8.0 to 22.0%, Cr: 0.1 to 8.0%, Mo: 2.0 to 10.0%, Co: 2.0 to 20.0%, Ti: 0.1% or less, Al: 2.5% or less, N: 0.03% or less, and O: 0.005% or less, with the balance being Fe and unavoidable impurities, wherein Baker-Nutting orientation relationship with an orientation difference within 10° exists between the Cr nitride precipitated in the nitrided layer and the matrix martensite.
    Type: Grant
    Filed: March 25, 2010
    Date of Patent: June 10, 2014
    Assignee: Hitachi Metals, Ltd.
    Inventors: Katsuhiko Ohishi, Toshihiro Uehara