Chromium Containing, But Less Than 9 Percent Patents (Class 420/104)
  • Patent number: 10308994
    Abstract: A seamless steel tube has a particular composition and a structure with an average prior ? grain size of 150 ?m or less in an axial cross-section after cold drawing and heat treatment. The structure retards the growth of a fatigue crack. The steel tube has a tensile strength TS of 500 MPa or more and good internal pressure fatigue resistance and is suitable for use as a fuel injection tube under high injection pressures. The composition of the steel tube may further contain at least one of Cu, Ni, Cr, Mo, and B; at least one of Ti, Nb, and V; and/or Ca.
    Type: Grant
    Filed: March 20, 2015
    Date of Patent: June 4, 2019
    Assignee: JFE Steel Corporation
    Inventors: Yoshikazu Kawabata, Manabu Nishino, Makio Gunji
  • Patent number: 10294557
    Abstract: A steel part having a homogeneous multiphase microstructure in each region of the part, the microstructure containing ferrite, wherein the steel part is obtained by a process involving: cutting a blank from a strip of steel, having a specified composition; optionally, the blank undergoes prior cold deformation; the blank is heated to reach a soak temperature Ts above Ac1 but below Ac3 and held at this soak temperature Ts for a soak time ts adjusted so that the steel, after the blank has been heated, has an austenite content equal to or greater than 25% by area; the heated blank is transferred into a forming tool to hot-form the part; and the part is cooled within the tool at a cooling rate V such that the microstructure of the steel, after cooling the part, is a multiphase microstructure containing ferrite and being homogeneous in each region of the part.
    Type: Grant
    Filed: January 5, 2012
    Date of Patent: May 21, 2019
    Assignee: ArcelorMittal France
    Inventors: Jacques Corquillet, Jacques Devroc, Jean-Louis Hochard, Jean-Pierre Laurent, Antoine Moulin, Nathalie Romanowski
  • Patent number: 10196781
    Abstract: The present invention discloses a method for preparing hypereutectoid steel rail in which the composition of the billets adopted is: C: 0.86-1.05 wt. %; Si: 0.3-1 wt. %; Mn: 0.5-1.3 wt. %; Cr: 0.15-0.35 wt. %; Cu: 0.3-0.5 wt. %; P: 0.02-0.04 wt. %; S: ?0.02 wt. %; Ni: ½-? of the content of Cu; at least one of V, Nb and Re; Fe and unavoidable impurities of the rest. The present invention further provides a hypereutectoid steel rail prepared by the foregoing method. By the hypereutectoid steel rail preparation method provided by the present invention, the high-carbon billets with a specific composition provided by the present invention can be made into hypereutectoid steel rails with good corrosion resistance and tensile properties.
    Type: Grant
    Filed: August 9, 2016
    Date of Patent: February 5, 2019
    Assignees: PANGANG GROUP PANZHIHUA IRON & STEEL RESEARCH INSTITUTE CO., LTD., PANGANG GROUP PANZHIHUA STEEL & VANADIUM CO., LTD.
    Inventors: Zhenyu Han, Ming Zou, Hua Guo, Yuan Wang, Dadong Li, Yong Deng, Jun Yuan
  • Patent number: 9097284
    Abstract: A vehicle wheel bearing apparatus has an outer member formed, on its inner circumference, with double row outer raceway surfaces. An inner member includes a wheel hub integrally formed with a wheel mounting flange at its one end. The wheel hub outer circumference surface has double row inner raceway surfaces arranged opposite to the double row outer raceway surfaces. Double row balls are freely rollably contained between the outer raceway surfaces and inner raceway surfaces, respectively, of the outer member and the inner member. A pitch circle diameter of the double row ball group of the outer-side is larger than a pitch circle diameter of the double row ball group of the inner-side. At least the outer member and the wheel hub are formed of medium/high carbon steel including carbon of 0.40˜0.80% by weight. The inner and outer raceway surfaces are formed, respectively, with predetermined hardened layers with a surface hardness of 58˜64 HRC.
    Type: Grant
    Filed: May 14, 2009
    Date of Patent: August 4, 2015
    Assignee: NTN Corporation
    Inventors: Hisashi Ohtsuki, Kouji Kametaka
  • Publication number: 20150147591
    Abstract: Disclosed herein are embodiments of iron-based corrosion resistant hardfacing alloys. The alloys can be designed through the use of different compositional, thermodynamic, microstructural, and performance criteria. In some embodiments, chromium content in the alloy can be increased while avoiding the formation of different hard chromium carbides, thereby increasing the corrosion resistance of the alloy.
    Type: Application
    Filed: November 26, 2014
    Publication date: May 28, 2015
    Inventors: Justin Lee Cheney, Shengjun Zhang, John Hamilton Madok, Jonathon Bracci
  • Patent number: 9039847
    Abstract: A multiphase steel sheet has a steel composition containing, in percent by mass, more than 0.015% to less than 0.100% of carbon, less than 0.40% of silicon, 1.0% to 1.9% of manganese, more than 0.015% to 0.05% of phosphorus, 0.03% or less of sulfur, 0.01% to 0.3% of soluble aluminum, 0.005% or less of nitrogen, less than 0.30% of chromium, 0.0050% or less of boron, less than 0.15% of molybdenum, 0.4% or less of vanadium, 0.02% or less of titanium, wherein [Mneq] is 2.0 to 2.8, the balance being iron and incidental impurities.
    Type: Grant
    Filed: July 27, 2010
    Date of Patent: May 26, 2015
    Assignee: JFE Steel Corporation
    Inventors: Yoshihiko Ono, Kenji Takahashi, Kaneharu Okuda, Shoichiro Taira, Michitaka Sakurai, Yusuke Fushiwaki
  • Publication number: 20150125339
    Abstract: A case hardening steel material having a chemical composition consists of, by mass percent, C: 0.15 to 0.23%, Si: 0.01 to 0.15%, Mn: 0.65 to 0.90%, S: 0.010 to 0.030%, Cr: 1.65 to 1.80%, Al: 0.015 to 0.060%, and N: 0.0100 to 0.0250%, further containing, as necessary, one or more kinds selected from Cu and Ni of predetermined amounts, the balance being Fe and impurities; 25?Mn/S?85, 0.90?Cr/(Si+2Mn)?1.20, and 1.16Si+0.70Mn+Cr?2.20; P, Ti and O in the impurities being P?0.020%, Ti?0.005%, and O?0.0015%; and having a structure consisting of 20 to 70% in an area ratio being ferrite; and the portion other than the ferrite being one or more kinds of pearlite and bainite. The steel material is used suitably as a raw material of the carburized part such as a CVT pulley shaft.
    Type: Application
    Filed: April 16, 2013
    Publication date: May 7, 2015
    Inventors: Hideki Imataka, Masayuki Horimoto, Gen Kato, Mitsuru Fijimoto
  • Publication number: 20150118097
    Abstract: High cleanliness spring steel useful in manufacturing a spring with SiO2-based inclusions being extremely controlled and excellent in fatigue properties is provided. High cleanliness spring steel which is steel containing; C: 1.2% (means mass %, hereafter the same with respect to the component) or below (not inclusive of 0%), Si: 1.2-4%, Mn: 0.1-2.0%, Al: 0.01% or below (not inclusive of 0%), and the balance comprising iron with inevitable impurities, wherein; the total of oxide-based inclusions of 4 or above of L (the large diameter of an inclusion)/D (the short diameter of an inclusion) and 25 ?m or above of D and oxide-based inclusions of less than 4 L/D and 25 ?m or above of L, in the oxide-based inclusions of 25 mass % or above of oxygen concentration and 70% (means mass %, hereafter the same with respect to inclusions) or above of SiO2 content when Al2O3 +MgO+CaO+SiO2+MnO=100% is presumed, out of inclusions in the steel, is 20 nos./500 g or below.
    Type: Application
    Filed: January 9, 2015
    Publication date: April 30, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Tomoko SUGIMURA, Sei KIMURA, Koichi SAKAMOTO, Atsuhiko YOSHIDA, Takeshi INOUE
  • Publication number: 20150098857
    Abstract: A steel material contains: by mass %, C: greater than 0.05% to 0.18%; Mn: 1% to 3%; Si: greater than 0.5% to 1.8%; Al: 0.01% to 0.5%; N: 0.001% to 0.015%; one or both of V and Ti: 0.01% to 0.3% in total; Cr: 0% to 0.25%; Mo: 0% to 0.35%; a balance: Fe and impurities; and 80% or more of bainite by area %, and 5% or more in total of one or two or more selected from a group consisting of ferrite, martensite and austenite by area %, in which an average block size of the above-described bainite is less than 2.0 ?m, an average grain diameter of all of the above-described ferrite, martensite and austenite is less than 1.0 ?m, an average nanohardness of the above-described bainite is 4.0 GPa to 5.0 GPa, and MX-type carbides each having a circle-equivalent diameter of 10 nm or more exist with an average grain spacing of 300 nm or less therebetween.
    Type: Application
    Filed: August 21, 2013
    Publication date: April 9, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kaori Kawano, Yasuaki Tanaka, Masahito Tasaka, Yoshiaki Nakazawa, Toshiro Tomida
  • Publication number: 20150090377
    Abstract: A steel sheet for hot pressing use according to the present invention has a specified chemical component composition, wherein some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, have an average equivalent circle diameter of 6 nm or less, the precipitated Ti amount and the total Ti amount in the steel fulfill the relationship represented by formula (1) shown below, and the sum total of the fraction of bainite and the fraction of martensite in the metal microstructure is 80 area % or more. Precipitated Ti amount (mass %)?3.4[N]?0.5×[(total Ti amount (mass %))?3.4[N]]??(1) (In the formula (1), [N] represents the content (mass %) of N in the steel.
    Type: Application
    Filed: March 1, 2013
    Publication date: April 2, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Junya Naitou, Keisuke Okita, Shushi Ikeda
  • Publication number: 20150079420
    Abstract: The steel for hot forming has the following composition in weight %: C: 0.10-0.25, Mn: 1.4-2.8, Si: ?1.0, Cr: ?1.0, Ti: ?0.05, Nb: ?0.05, V: ?0.1, Mo: ?0.1, Al: ?0.05, P: ?0.02, S: ?0.005, Ca: ?0.005, O: ?0.01, N: ?0.02, B: ?0.0004, the remainder being iron and unavoidable impurities. Also disclosed is a strip, sheet or blank produced with such a steel, a method for producing a hot formed product, such a product and the use thereof.
    Type: Application
    Filed: September 17, 2014
    Publication date: March 19, 2015
    Inventors: David Neal HANLON, Stefanus Matheus Cornelis VAN BOHEMEN
  • Publication number: 20150071812
    Abstract: A steel material having a chemical composition of, by mass %, C: greater than 0.05% to 0.2%, Mn: 1% to 3%, Si: greater than 0.5% to 1.8%, Al: 0.01% to 0.5%, N: 0.001% to 0.015%, Ti or a sum of V and Ti: greater than 0.1% to 0.25%, Ti: 0.001% or more, Cr: 0% to 0.25%, Mo: 0% to 0.35%, and a balance: Fe and impurities, includes a steel structure being a multi-phase structure having a main phase made of ferrite of 50 area % or more, and a second phase containing one or two or more selected from a group consisting of bainite, martensite and austenite, in which an average nanohardness of the above-described second phase is less than 6.
    Type: Application
    Filed: July 22, 2013
    Publication date: March 12, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kaori Kawano, Masahito Tasaka, Yoshiaki Nakazawa, Yasuaki Tanaka, Toshiro Tomida
  • Publication number: 20150059933
    Abstract: A steel comprises, by mass percent, C: 0.10 to 0.15%, Si: not less than 0.02% and less than 0.10%, Mn: more than 0.90% and not more than 2.50%, P?0.030%, S?0.050%, Cr: 0.80 to 2.0%, V: 0.05 to 0.50%, Al: 0.01 to 0.07%, N?0.0080%, O?0.0030%, and one or more selected from Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, the balance being Fe and impurities. The composition satisfies [35?Mn/S?200], [20?(669.3×logeC?1959.6×logeN?6983.3)×(0.067×Mo+0.147×V)?80], [140×Cr+125×Al+235×V?160] and [150?511×C+33×Mn+56×Cu+15×Ni+36×Cr+5×Mo+134×V?200].
    Type: Application
    Filed: February 28, 2013
    Publication date: March 5, 2015
    Inventors: Hideki Imataka, Masayuki Horimoto, Yuya Gyotoku, Kosuke Tanaka
  • Publication number: 20150053315
    Abstract: Provided are: a boron-added high strength steel for bolt excellent in delayed fracture resistance even having a tensile strength of 1100 MPa or more without addition of large amounts of expensive alloy elements such as Cr and Mo: and a high strength bolt made from the boron-added high strength steel for bolt. The high strength steel for bolt contains C of 0.23% to less than 0.40%, Si of 0.23% to 1.50%, Mn of 0.30% to 1.45%, P of 0.03% or less (excluding 0%), S of 0.03% or less (excluding 0%), Cr of 0.05% to 1.5%, V of 0.02% to 0.30%, Ti of 0.02% to 0.1%, B of 0.0003% to 0.0050%, Al of 0.01% to 0.10%, and N of 0.002% to 0.010%, with the remainder being iron and inevitable impurities. The steel has a ratio ([Si]/[C]) of the Si content [Si] to the C content [C] of 1.0 or more and has a ferrite-pearlite mixed microstructure.
    Type: Application
    Filed: February 5, 2013
    Publication date: February 26, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yosuke Matsumoto, Atsushi Inada, Masamichi Chiba
  • 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
  • Publication number: 20150041029
    Abstract: The present invention is a steel for a mechanical structure for cold working, the steel characterized in containing C, Si, Mn, P, S, Al, N, and Cr, the remainder being iron and inevitable impurities; the metal composition having pearlite and pro-eutectoid ferrite; the combined area of the pearlite and pro-eutectoid ferrite being 90% or more of the total composition; the area percentage A of the pro-eutectoid ferrite having the relationship A>Ae, where Ae=(0.8?Ceq)×96.75 (Ceq=[C]+0.1×[Si]+0.06×[Mn]?0.11×[Cr], and “(element names)” indicates the element content (percent in mass); and the mean grain size of the pro-eutectoid ferrite and the ferrite in the pearlite being 15 to 25 ?m.
    Type: Application
    Filed: April 4, 2013
    Publication date: February 12, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Koji Yamashita, Takehiro Tsuchida, Masamichi Chiba
  • Publication number: 20150044086
    Abstract: A steel wire rod or steel bar as hot-rolled, including: by mass %: C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.5%, Al: 0.015 to 0.3%, and N: 0.0040 to 0.0150%, and P: limited to 0.035% or less and S: limited to 0.025% or less, and the balance substantially consisting of iron and unavoidable impurities, wherein a depth of d (mm) from the surface of the surface layer region with 20 HV 0.2 or more higher, relative to HV 0.2 that is the average hardness in the region where the depth from the surface is from sectional radius R×0.5 (mm) to the center satisfies the formula (1); the steel structure of the surface layer region has a ferrite fraction of 10% or less by area ratio, with the balance being one or two or more of martensite, bainite and pearlite; the steel structure where the depth from the surface is from the sectional radius R×0.
    Type: Application
    Filed: April 1, 2013
    Publication date: February 12, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kei Miyanishi, Atsushi Monden, Shingo Yamasaki, Shunta Homma
  • Patent number: 8951364
    Abstract: The invention relates to an Fe—Co alloy, the composition of which comprises in % by weight: 6?Co+Ni?22 Si?0.2 0.5?Cr?8 Ni?4 0.10?Mn?0.90 Al?4 Ti?1 C?1 Mo?3 V+W?3 Nb+Ta?1 Si+Al?6 O+N+S+P+B?0.1 the balance of the composition consisting of iron and inevitable impurities due to the smelting, it being furthermore understood that the contents thereof satisfy the following relationships: Co+Si?Cr?27 Si+Al+Cr+V+Mo+Ti?3.5 1.23(Al+Mo)+0.84(Si+Cr+V)?1.3 14.5(Al+Cr)+12(V+Mo)+25 Si?50.
    Type: Grant
    Filed: January 14, 2009
    Date of Patent: February 10, 2015
    Assignee: Aperam Alloys Imphy
    Inventors: Thierry Waeckerle, Herve Fraisse
  • Publication number: 20150034215
    Abstract: A high-strength multi-phase steel having tensile strengths of no less than 580 MPa, preferably with a dual-phase structure for a cold-rolled or hot-rolled steel strip having improved forming properties, in particular for lightweight vehicle construction is disclosed, containing the following elements (contents in % by mass): C 0.075 to ?0.105; Si 0.200 to ?0.300; Mn 1.000 to ?2.000; Cr 0.280 to ?0.480; Al 0.10 to ?0.060; P ?0.020; Nb ?0.005 to ?0.025; N ?0.0100; S ?0.0050; the remainder iron, including conventional steel-accompanying elements not mentioned above.
    Type: Application
    Filed: February 27, 2013
    Publication date: February 5, 2015
    Inventors: Thomas Schulz, Andreas Wedemeier, Michael Pohl, Hans-Joachim Kratz, Matthias Geler, Oliver Meyer
  • Publication number: 20150034049
    Abstract: A rolled steel bar for hot forging consisting, by mass percent, of C: 0.25-0.50%, Si: 0.40-1.0%, Mn: 1.0-1.6%, S: 0.005-0.035%, Al: 0.005-0.050%, V: 0.10-0.30%, and N: 0.005-0.030%, and the balance of Fe and impurities, i.e., P: 0.035% or less and O: 0.0030% or less, wherein Fn1=C+Si/10+Mn/5+5Cr/22+1.65V?5S/7 is 0.90 to 1.20. The predicted maximum width of nonmetallic inclusions at the time when a cumulative distribution function obtained by extreme value statistical processing by taking the width of nonmetallic inclusion in an R1/2 part of a longitudinal cross section of the steel bar as W (mm) is 99.99% is 100 mm or narrower. The number density of sulfides each having a circle-equivalent diameter of 0.3 to 1.0 mm observed per unit area of the R1/2 part of a transverse cross section of the steel bar is 500 pieces/mm2 or higher.
    Type: Application
    Filed: February 5, 2013
    Publication date: February 5, 2015
    Inventors: Naoki Matsui, Masashi Higashida, Hitoshi Matsumoto, Yutaka Neishi, Talzo Makino, Kouji Morita, Yoshihiro Tanimura, Naoyuki Sashima, Toshimasa Itou
  • Publication number: 20150027591
    Abstract: A steel material for nitriding has a composition comprising, by mass percent, C: more than 0.15% and not more than 0.35%, Si?0.20%, Mn: 0.10 to 2.0%, P?0.030%, S?0.050%, Cr: 0.80 to 2.0%, V: 0.10 to 0.50%, Al: 0.01 to 0.06%, N?0.0080%, O?0.0030%, and optionally one or more elements of Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb, the balance being Fe and impurities. The composition satisfies the conditions of [20?(669.3×logeC?1959.6×logeN?6983.3)×(0.067×Mo+0.147×V)?80] and [140×Cr+125×Al+235×V?160]. The microstructure is a ferritic-pearlitic structure, a ferritic-bainitic structure, or a ferritic-pearlitic-bainitic structure. The area fraction of ferrite is 20% or more and the precipitate content of V is 0.10% or less.
    Type: Application
    Filed: February 4, 2013
    Publication date: January 29, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuya Gyotoku, Masayuki Horimoto, Hideki Imataka, Kosuke Tanaka
  • Publication number: 20150027602
    Abstract: A steel sheet for hot pressing use according to the present invention has a specified chemical component composition, wherein some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, have an average equivalent circle diameter of 3 nm or more, the precipitated Ti amount and the total Ti amount in the steel fulfill the relationship represented by formula (1) shown below, and the sum total of the fraction of bainite and the fraction of martensite in the metal microstructure is 80 area % or more. Precipitated Ti amount (mass %)?3.4[N]>0.5×[total Ti amount (mass %)?3.4[N]]??(1) (In the formula (1), [N] represents the content (mass %) of N in the steel.
    Type: Application
    Filed: March 1, 2013
    Publication date: January 29, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Junya Naitou, Keisuke Okita, Shushi Ikeda
  • Publication number: 20150030870
    Abstract: Provided is a carbon tool steel strip suitable for use in various spring materials, valve materials, and the like, in which press punching properties and fatigue characteristics are enhanced. A carbon tool steel strip having a thickness of 1 mm or less and a carbon tool steel composition containing 0.8-1.2% C by mass %, wherein the carbon tool steel strip has a Vickers hardness of 500-650 (Hv), and when a cross-section at the center in the sheet thickness direction of the carbon tool steel strip is viewed with the plane of observation in a direction at a right angle to a rolled surface of the carbon tool steel strip and in the length direction of the carbon tool steel strip, the area ratio of carbides having an equivalent circle diameter of at least 0.5 ?m among the carbides present in the metallographic structure is 0.50-4.30%.
    Type: Application
    Filed: March 6, 2013
    Publication date: January 29, 2015
    Applicant: HITACHI METALS, LTD.
    Inventors: Tomonori Ueno, Hiroyoshi Fujihara, Ichirou Kishigami
  • Publication number: 20150020992
    Abstract: A non-scaling heat-treatable steel with particular suitability for producing hardened or die-hardened components is disclosed, characterized by the following chemical composition in % by weight: C 0.04-0.50; Mn 0.5-6.0; Al 0.5-3.0; Si 0.05-3.0; Cr 0.05-3.0; Ni less than 3.0; Cu less than 3.0; Ti 0.010-?0.050; B 0.0015-?0.0040; P less than 0.10; S less than 0.05; N less than 0.020; remainder iron and unavoidable impurities. Further disclosed is a method for producing a non-scaling hardened component from the steel and a method for producing a hot strip from a steel.
    Type: Application
    Filed: March 19, 2013
    Publication date: January 22, 2015
    Inventors: Joachim Schöttler, Friedrich Luther, Stefan Mütze
  • Publication number: 20150023834
    Abstract: A hot-rolled steel sheet including, in terms of % by mass, 0.030% to 0.120% of C, 1.20% or less of Si, 1.00% to 3.00% of Mn, 0.01% to 0.70% of Al, 0.05% to 0.20% of Ti, 0.01% to 0.10% of Nb, 0.020% or less of P, 0.010% or less of S, and 0.005% or less of N, and a balance consisting of Fe and impurities, in which 0.106?(C %-Ti %*12/48-Nb %*12/93)>0.012 is satisfied; a pole density of {112}(110) at a position of ¼ plate thickness is 5.7 or less; an aspect ratio (long axis/short axis) of prior austenite grains is 5.3 or less; a density of (Ti, Nb)C precipitates having a size of 20 nm or less is 109 pieces/mm3 or more; a yield ratio YR, which is the ratio of a tensile strength to a yield stress, is 0.80 or more; and a tensile strength is 590 MPa or more.
    Type: Application
    Filed: January 8, 2013
    Publication date: January 22, 2015
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Eisaku Sakurada, Kunio Hayashi, Koichi Sato, Shunji Hiwatashi
  • Publication number: 20150024237
    Abstract: A hot stamping steel material, which secures good hydrogen embrittlement resistance even when the steel sheet after hot stamping is subjected to processing leading to remaining of stress, such as piercing and which is easily practicable, wherein the steel sheet has the chemical composition of: C: 0.18 to 0.26%; Si: more than 0.02% and not more than 0.05%; Mn: 1.0 to 1.5%; P: 0.03% or less; S: 0.02% or less; Al: 0.001 to 0.5%; N: 0.1% or less; O: 0.001 to 0.02%; Cr: 0 to 2.0%; Mo: 0 to 1.0%; V: 0 to 0.5%; W: 0 to 0.5%; Ni: 0 to 5.0%; B: 0 to 0.01%; Ti: 0 to 0.5%; Nb: 0 to 0.5%; Cu: 0 to 1.0%; and balance: Fe and impurities, in terms of % by mass, the concentration of a Mn-containing inclusion is not less than 0.010% by mass and less than 0.25% by mass, and the number ratio of a Mn oxide to the inclusion having a maximum length of 1.0 to 4.0 ?m is 10.0% or more.
    Type: Application
    Filed: March 5, 2013
    Publication date: January 22, 2015
    Inventors: Hiroyuki Tanahashi, Toshimasa Tomokiyo
  • Publication number: 20140363329
    Abstract: A rolled steel bar or wire rod having hot surface fatigue strength, wear resistance, and machinability even after hot forging has a composition containing C, Si, Mn, S, Cr, Mo (optional), Al, and N, with the balance being Fe and impurities. The chemical composition satisfies that fn1 defined by Formula (1) is 1.60 to 2.10. The structure of the rolled steel bar or wire rod for hot forging includes a ferrite-pearlite structure, a ferrite-pearlite-bainite structure, or a ferrite-bainite structure. A maximum value/a minimum value of average ferrite grain size, which is observed and measured randomly in 15 visual fields each having an area of 62500 ?m2 in a cross section, is not more than 2.0. fn1=Cr+2×Mo (1), and each symbol of elements in Formula (1) is substituted by a content (mass %) of a corresponding element.
    Type: Application
    Filed: August 22, 2012
    Publication date: December 11, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Akira Shiga, Masayuki Horimoto, Yoshihiro Daitoh, Hideki Imataka, Yusuke Usui, Tetsuya Ohashi
  • Publication number: 20140348695
    Abstract: A low alloy steel, containing, by mass percent, C: 0.01 to 0.15%, Si: 3% or less, Mn: 3% or less, B: 0.005 to 0.050%, and Al: 0.08% or less, and the balance being Fe and impurities, wherein in the impurities, N: 0.01% or less, P: 0.05% or less, S: 0.03% or less, and O: 0.03% or less. In the alloy steel, a HAZ has excellent resistance to embrittlement attributable to hydrogen such as stress corrosion cracking in wet hydrogen sulfide environments.
    Type: Application
    Filed: December 17, 2012
    Publication date: November 27, 2014
    Inventors: Hiroyuki Hirata, Kenji Kobayashi, Tomohiko Omura, Kaori Kawano, Kota Tomatsu, Kazuhiro Ogawa
  • Publication number: 20140338797
    Abstract: Steel with high strength and good formability is produced with compositions and methods for forming austenitic and martensitic microstructure in the steel. Carbon, manganese, molybdenum, nickel copper and chromium may promote the formation of room temperature stable (or meta-stable) austenite by mechanisms such as lowering transformation temperatures for non-martensitic constituents, and/or increasing the hardenability of steel. Thermal cycles utilizing a rapid cooling below a martensite start temperature followed by reheating may promote formation of room temperature stable austenite by permitting diffusion of carbon into austenite from martensite.
    Type: Application
    Filed: May 16, 2014
    Publication date: November 20, 2014
    Inventors: Grant A. Thomas, Jose Mauro B. Losz
  • Publication number: 20140338798
    Abstract: Steel with high strength and good formability is produced with compositions and methods for forming austenitic and martensitic microstructure in the steel. Carbon, manganese, molybdenum, nickel copper and chromium may promote the formation of room temperature stable (or meta-stable) austenite by mechanisms such as lowering transformation temperatures for non-martensitic constituents, and/or increasing the hardenability of steel. Thermal cycles utilizing a rapid cooling below a martensite start temperature followed by reheating may promote formation of room temperature stable austenite by permitting diffusion of carbon into austenite from martensite.
    Type: Application
    Filed: May 16, 2014
    Publication date: November 20, 2014
    Inventors: Grant A. Thomas, Luis G. Garza-Martinez
  • Publication number: 20140322066
    Abstract: A rolled steel bar has a composition consisting, by mass percent, of C: 0.27 to 0.37%, Si: 0.30 to 0.75%, Mn: 1.00 to 1.45%, S: 0.008% or more and less than 0.030%, Cr: 0.05 to 0.30%, Al: 0.005 to 0.050%, V: 0.200 to 0.320%, and N: 0.0080 to 0.0200%, the balance being Fe and impurities. The contents of P, Ti and O in the impurities are, by mass percent, P: 0.030% or less, Ti: 0.0040% or less, and O: 0.0020% or less. Y1 expressed by the formula <1> is 1.05 to 1.18. Y1=C+(1/10)Si+(1/5)Mn+(5/22)Cr+1.65V?(5/7)S ??<1>. C, Si, Mn, Cr, V, and S in the formula represent mass percent of the elements. A hot-forged part having a tensile strength of 900 MPa or higher and a transverse endurance ratio of 0.47 can be obtained by the rolled steel bar.
    Type: Application
    Filed: November 7, 2012
    Publication date: October 30, 2014
    Inventors: Masashi Higashida, Hitoshi Matsumoto, Naoki Matsui, Yutaka Neishi, Taizo Makino
  • Publication number: 20140314616
    Abstract: Provided is a hot-rolled steel sheet having a composition containing 0.04 mass percent to 0.20 mass percent C, 0.7 mass percent to 2.3 mass percent Si, 0.8 mass percent to 2.8 mass percent Mn, 0.1 mass percent or less P, 0.01 mass percent or less S, 0.1 mass percent or less Al, and 0.008 mass percent or less N, the remainder being Fe and inevitable impurities. Internal oxides containing one or more selected from the group consisting of Si, Mn, and Fe are present at grain boundaries and in grains in a base metal. The internal oxides present at the grain boundaries in the base metal are located within 5 ?m from the surface of the base metal. The difference between the depths at which the internal oxides are formed in the cross direction of the steel sheet is 2 ?m or less.
    Type: Application
    Filed: November 2, 2012
    Publication date: October 23, 2014
    Applicant: JFE STEEL CORPORATION
    Inventors: Mai Miyata, Yoshitsugu Suzuki, Yasunobu Nagataki, Yoshiyasu Kawasaki, Hirokazu Sugihara
  • Publication number: 20140308156
    Abstract: Provided are a steel sheet for warm press forming that can have high strength, good elongation, and thus improved crashworthiness after being warm pressed, and a warm-pressed member formed of the steel sheet, and manufacturing methods thereof. The steel sheet for warm press forming includes, by weight %, C: 0.01% to 0.5%, Si: 3.0% or less (excluding 0%), Mn: 3% to 15%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, Al: 3.0% or less (excluding 0%), N: 0.03% or less (excluding 0%), and the balance of Fe and inevitable impurities.
    Type: Application
    Filed: November 5, 2012
    Publication date: October 16, 2014
    Inventors: Jin-Keun Oh, Kyoo-Young Lee, Yeol-Rae Cho, Eul-Yong Choi, Ki-Soo Kim
  • Publication number: 20140301888
    Abstract: This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070?Nb+125B?0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 ?m, and the thickness of a flange falls in a range of 12 to 40 mm.
    Type: Application
    Filed: December 12, 2012
    Publication date: October 9, 2014
    Inventors: Kazutoshi Ichikawa, Teruyuki Wakatsuki, Noriaki Onodera, Kohichi Yamamoto
  • Publication number: 20140271331
    Abstract: This high-strength steel plate has a component composition including, by mass %, C: 0.02-0.3%, Si: 1-3%, Mn: 1.8-3%, P: 0.1% or less, S: 0.01% or less, Al: 0.001-0.1%, N: 0.002-0.03%, the rest consisting of iron and impurities. Said steel plate has a microstructure including, in terms of area ratio relative to the entire microstructure, each of the following phases: bainitic ferrite: 50-85%; retained ?; 3% or greater; martensite+the aforementioned retained ?; 10-45%; and ferrite: 5-40%. The C concentration (C?R) in the aforementioned retained austenite is 0.3-1.2 mass %, part or all of the N in the aforementioned component composition is solid solution N, and the amount of said solid solution N is 30-100 ppm.
    Type: Application
    Filed: August 15, 2012
    Publication date: September 18, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Elijah Kakiuchi, Hideo Hata, Naoki Mizuta, Tatsuya Asai
  • Publication number: 20140251085
    Abstract: The present invention provides a powder core used for high-frequency magnetic components and a soft magnetic metal powder which is suitable for the manufacturing of the above-described powder core. The invention relates to a soft magnetic metal powder, consisting of, in terms of mass %: 0.5% to 10.0% of Si, 1.5% to 8.0% of Cr, and 0.05% to 3.0% of Sn, with the balance being Fe and unavoidable impurities.
    Type: Application
    Filed: March 4, 2014
    Publication date: September 11, 2014
    Inventors: Mikiko Tsutsui, Yuichiro Fujita
  • Patent number: 8828153
    Abstract: A high-strength cold-rolled steel sheet providing a product with a good surface condition after press forming, having excellent bake hardenability and anti room temperature aging property, and having a dual phase structure with a tensile strength of at least 340 MPa is provided. A high-strength cold-rolled steel sheet has a structure comprising a main phase which is a ferrite and a secondary phase which is a low temperature transformation product including a martensite and has a hardness distribution of the ferrite phase in an arbitrary cross section having a length of 10 mm in the widthwise 10 direction of the sheet which satisfies the relationship prescribed by (HV(max)?HV(ave))<0.5×(Hv(ave). HV(max) is the maximum Vickers hardness of ferrite grains in a region at a distance of from (?)t to (¼)t in the thickness direction from the surface when the thickness of the high-strength cold-rolled steel sheet is t, and Hv(ave) is the average Vickers hardness of ferrite grains in this region.
    Type: Grant
    Filed: December 8, 2010
    Date of Patent: September 9, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Jun Haga, Nobusato Kojima
  • Patent number: 8828557
    Abstract: A high strength galvanized steel sheet including all in mass %, C: 0.05% to <0.12%, Si: 0.35% to <0.80%, Mn: 2.0 to 3.5%, P: 0.001 to 0.040%, S: 0.0001 to 0.0050%, Al: 0.005 to 0.1%, N: 0.0001 to 0.0060%, Cr: 0.01% to 0.5%, Ti: 0.010 to 0.080%, Nb: 0.010 to 0.080%, and B: 0.0001 to 0.0030%, optionally one or more of Mo: 0.01 to 0.15%, Ca: 0.0001 to 0.0050%, REM: 0.0001 to 0.1%, and Sb: 0.0001 to 0.1%, and Fe and unavoidable impurities as the balance, has a microstructure containing a ferrite phase with a volume fraction in a range of 20 to 70% and an average grain diameter equal to or smaller than 5 ?m, and has a galvanized layer on a surface thereof at a coating weight (per side) of 20 to 150 g/m2.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: September 9, 2014
    Assignee: JFE Steel Corporation
    Inventors: Shusaku Takagi, Kohei Hasegawa
  • Publication number: 20140241933
    Abstract: A high-strength cold-rolled steel sheet excellent in ductility, work hardenability, and stretch flangeability, and having tensile strength of 780 MPa or more includes: a chemical composition containing, in mass percent, C: more than 0.020% to less than 0.30%, Si: more than 0.10% to 3.00% or less, Mn: more than 1.00% to 3.50% or less; and metallurgical structure whose main phase is a low-temperature transformation product, and whose secondary phase contains retained austenite. The retained austenite has a volume fraction relative to overall structure of more than 4.0% to less than 25.0% and an average grain size of less than 0.80 ?m, and of the retained austenite, the number density of retained austenite grains whose grain size is 1.2 ?m or more is 3.0×10?2 grains/?m2 or less.
    Type: Application
    Filed: June 27, 2012
    Publication date: August 28, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Jun Haga, Takuya Nishio, Masayuki Wakita, Yasuaki Tanaka, Norio Imai, Toshiro Tomida
  • Patent number: 8815025
    Abstract: A high strength steel, including about 0.05 to about 0.25% of C, less than about 0.5% of Si, about 0.5 to about 3.0% of Mn, not more than about 0.06% of P, not more than about 0.01% of S, about 0.50 to about 3.0% of Sol. Al, not more than about 0.02% of N, about 0.1 to about 0.8% of Mo, about 0.02 to about 0.40% of Ti, and the balance of iron and unavoidable impurities, wherein the steel has a structure formed of at least three phases including a bainite phase, and a retained austenite phase in addition to a ferrite phase having a composite carbide containing Ti and Mo dispersed and precipitated therein, wherein the total volume of the ferrite phase and the bainite phase is not smaller than 80%, the volume of the bainite phase is about 5% to about 60%, and the volume of the retained austenite phase is about 3 to about 20%.
    Type: Grant
    Filed: November 3, 2006
    Date of Patent: August 26, 2014
    Assignees: JFE Steel Corporation, ThyssenKrupp Steel AG
    Inventors: Takeshi Yokota, Akio Kobayashi, Kazuhiro Seto, Yoshihiro Hosoya, Thomas Heller, Brigitte Hammer, Rolf Bode, Günter Stich
  • Patent number: 8801874
    Abstract: A steel plate for line pipes containing, in terms of % by weight, C: 0.02 to 0.06%, Si: 0.5% or less, Mn: 0.8 to 1.6%, P: 0.008% or less, S: 0.0008% or less, Al: 0.08% or less, Nb: 0.005 to 0.035%, Ti: 0.005 to 0.025%, and Ca: 0.0005 to 0.0035%, and optionally contains one or more of Cu: 0.5% or less, Ni: 1% or less, Cr: 0.5% or less, Mo: 0.5% or less and V: 0.1% or less, and has a CP value of 0.95 or less represented by CP=4.46C(%)+2.37Mn(%)/6+{1.18Cr(%)+1.95Mo(%)+1.74V(%)}/5+{1.74Cu(%)+1.7Ni(%)}/15+22.36P(%), and a Ceq value of 0.30 or more represented by Ceq=C(%)+Mn(%)/6+{Cr(%)+Mo(%)+V(%)}/5 +{Cu(%)+Ni(%)}/15.
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: August 12, 2014
    Assignee: JFE Steel Corporation
    Inventors: Nobuyuki Ishikawa, Makoto Suzuki, Tomohiro Matsushima, Akiyoshi Tsuji, Shinichi Kakihara, Nobuo Shikanai, Yutaka Awajiya
  • Patent number: 8801872
    Abstract: A case hardened gear steel having enhanced core fracture toughness includes by weight percent about 16.3Co, 7.5Ni, 3.5Cr, 1.75Mo, 0.2W, 0.11C, 0.03Ti, and 0.02V and the balance Fe, characterized as a predominantly lath martensitic microstructure essentially free of topologically close-packed (TCP) phases and carburized to include fine M2C carbides to provide a case hardness of at least about 62 HRC and a core toughness of at least about 50 ksi?in.
    Type: Grant
    Filed: August 20, 2008
    Date of Patent: August 12, 2014
    Assignee: QuesTek Innovations, LLC
    Inventors: James A. Wright, Jason Sebastian
  • Publication number: 20140219859
    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: Application
    Filed: February 10, 2014
    Publication date: August 7, 2014
    Applicant: Scoperta, Inc.
    Inventors: Justin Lee Cheney, John Hamilton Madok
  • Publication number: 20140193288
    Abstract: The present invention provides a spring steel, which is finally formed into a spring, by making use of, at a maximum, the temper softening resistance effect due to alloying elements while suppressing the formation of hard inclusions of SiO2 and the generation of decarburization, which may cause deterioration of fatigue characteristics of the spring. The spring steel is characterized by comprising, in % by mass, C: 0.50 to 0.70%, Si: 1.00 to 5.00%, Mn: 0.30 to 2.00%, P: 0.0002 to 0.0500%, S: 0.0002 to 0.0500%, Cr: 0.10 to 3.50%, Al: 0.0005 to 0.0500%, and N: 0.0020 to 0.0100%, with the balance being Fe and inevitable impurities, wherein the H-value defined by the following equation (a) is 160 or more, and the C-value defined by the following equation (b) is 3.25 or less: H=33.6[C]+10.0[Si]+5.95[Mn]+11.1[Cr]+90.0??(a), and C=[Si]/[Mn]??(b).
    Type: Application
    Filed: August 15, 2012
    Publication date: July 10, 2014
    Inventors: Shinya Teramoto, Manabu Kubota
  • Publication number: 20140182414
    Abstract: There is provided an induction hardening steel excellent in quenching crack resistance. The induction hardening steel of the present embodiment includes, by mass percent, C: 0.35 to 0.6%, Si: at least 0.01% and less than 0.40%, Mn: 1.0 to 2.0%, S: more than 0.010% and at most 0.05%, Cr: 0.01 to 0.5%, Al: 0.001 to 0.05%, N: Ti/3.4 to 0.02%, and Ti: 0.005 to 0.05%, the balance being Fe and impurities, and satisfies the following formula (1): 2S-3Ti<0.040??(1) where, into each element symbol in formula (1), the content (mass %) of the corresponding element is substituted.
    Type: Application
    Filed: July 4, 2012
    Publication date: July 3, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kisung Kim, Hiroaki Tahira, Kaori Kawano, Koji Watari
  • Publication number: 20140161659
    Abstract: This high-strength hot-rolled steel plate contains specific amounts of C, Si, Mn, Al, V and also Ti and/or Nb so as to fulfill C?12(V/51+Ti/48+Nb/93)>0.03, and the rest consists of iron and unavoidable impurities. Ferrite is the main microstructure, the remaining microstructure is one or more selected from the group consisting of bainite, martensite and retained austenite, wherein the average particle diameter of precipitated carbides (the total content of V, Ti and Nb is 0.02% or greater) in the ferrite is less than 6 nm.
    Type: Application
    Filed: August 15, 2012
    Publication date: June 12, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Masao Kinefuchi, Hideo Hata
  • Publication number: 20140150249
    Abstract: A semi-processed electrical steel is provided comprising the elements .005 ? Tin ? .09% 0 < Carbon ? 0.050% .10 ? Manganese ? 1.00% .005 ? Phosphorus ? .120% .0 < Sulfur ? .010% .50 ? Silicon ? 2.50% .01 ? Aluminum ? 1.60% .0 ? Antimony < .
    Type: Application
    Filed: December 3, 2012
    Publication date: June 5, 2014
    Inventor: Gwynne Johnston
  • 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: 8709336
    Abstract: The invention concerns a method for making an abrasion resistant steel plate having a chemical composition comprising: 0.35%?C?0.8%, 0%?Si?2%, 0%?Al?2%, 0.35%?Si+Al?2%, 0%?Mn?2.5%, 0%?Ni?5%, 0%?Cr?5%, 0%?Mo?0.50%, 0%?W?1.00%, 0.1%?Mo+W/2?0.50%, 0%?B?0.02%, 0%?Ti?2%, 0%?Zr?4%, 0.05%?Ti+Zr/2?2%, 0%?S?0.15%, N<0.03%; optionally from 0% to 1.5% of Cu; optionally Nb, Ta or V with Nb/2+Ta/4+V?0.5%; optionally less than 0.1% of Se, Te, Ca, Bi or Pb; the rest being iron and impurities; the composition satisfying: 0.1%?C*=C?Ti/4?Zr/8+7×N/8?0.55% and 1.05×Mn+0.54×Ni+0.50×Cr+0.3×(Mo+W/2)1/2+K>1.8, with K=0.5 if B?0.0005% and K=0 if B<0.0005% and Ti+Zr/2?7×N/2?0.05%; hardening after austenitization while cooling at a speed>0.5° C./s between a temperature>AC3 and ranging between T=800?270×C*?90×Mn?37×Ni?70×Cr?83×(Mo+W/2) and T?50° C.; then at a core speed Vr<115×ep?1.7 between T and 100° C., (ep=plate thickness in mm); cooling down to room temperature. The invention also concerns the resulting plate.
    Type: Grant
    Filed: June 17, 2008
    Date of Patent: April 29, 2014
    Assignee: Industeel Creusot
    Inventors: Jean Beguinot, Jean-Georges Brisson
  • Patent number: RE44940
    Abstract: Hot-rolled steel sheet which then can be cold-rolled, coated, the steel in the sheet having the following composition by weight: 0.15%<carbon<0.5% 0.5%<manganese<3% 0.1%<silicon<0.5% 0.01%<chromium<1% titanium<0.2% aluminum<0.1% phosphorus<0.1% sulfur<0.05% 0.0005%<boron<0.08%, the remainder being iron and impurities inherent in processing, the shoot ensuring a very high mechanical resistance after thermal treatment and the aluminum-based coating ensuring a high resistance to corrosion.
    Type: Grant
    Filed: April 15, 2013
    Date of Patent: June 10, 2014
    Assignees: ArcelorMittal France, ArcelorMittal Atlantique et Lorraine
    Inventors: Jean-Pierre Laurent, Jean-Paul Hennechart, Dominique Spehner, Jacques Devroc