Three Percent Or More Manganese Containing Or Containing Other Transition Metal In Any Amount Patents (Class 148/337)
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Publication number: 20100132848Abstract: The ultrahigh-strength steel sheet contains, in mass %, C: 0.05-0.25%, Si: 1.00-2.5%, Mn: 2.0-4.0%, P: 0.1% or below (not inclusive of 0%), S: 0.05% or below (not inclusive of 0%), Al: 0.01-0.15%, Ti: 0.003-0.10%, N: 0.01% or below (not inclusive of 0%), the balance comprising iron with inevitable impurities, and is a composite structure steel sheet comprising 10-50 area % ferrite and 50 area % or above martensite, in which the average circle-equivalent grain diameter of ferrite grains is 2.0 ?m or below, the average aspect ratio of ferrite grains is 2.0 or below, and the tensile strength is 1,100 MPa or above. Accordingly, the ultrahigh-strength steel sheet is excellent in hydrogen embrittlement resistance and workability.Type: ApplicationFiled: November 2, 2009Publication date: June 3, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd)Inventors: Muneaki Ikeda, Yukihiro Utsumi
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Publication number: 20100108201Abstract: This hot rolled steel contains, in terms of mass %, C: 0.01 to 0.1%, Si: 0.01 to 0.1%, Mn: 0.1 to 3%, P: not more than 0.1%, S: not more than 0.03%, Al: 0.001 to 1%, N: not more than 0.01%, Nb: 0.005 to 0.08%, and Ti: 0.001 to 0.2%, with a remainder being iron and unavoidable impurities, wherein a formula: [Nb]×[C]?4.34×10?3 is satisfied, a grain boundary density of solid solution C is not less than 1 atom/nm2 and not more than 4.5 atoms/nm2, and a grain size of cementite grains precipitated at grain boundaries within the steel sheet is not more than 1 um. This method for manufacturing a hot rolled steel sheet includes: heating a steel slab having the same composition as the above hot rolled steel sheet at a temperature that is not less than a temperature of SRTmin (° C.) and not more than 1,170° C.; performing rough rolling at a finishing temperature of not less than 1,080° C. and not more than 1,150° C.Type: ApplicationFiled: March 27, 2008Publication date: May 6, 2010Inventors: Tatsuo Yokoi, Kazuya Ootsuka, Yukiko Yamaguchi, Tetsuya Yamada
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Publication number: 20100108200Abstract: A high-strength hot-dip galvanized steel sheet excellent in workability according to the present invention: contains C, Si, Mn and other elements; has a dual phase structure containing ferrite and martensite as the metallographic structure; and, in the ferrite structure, satisfies the expression 0.2?(Lb/La)?1.Type: ApplicationFiled: October 1, 2009Publication date: May 6, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd)Inventors: Yuichi FUTAMURA, Masaaki Miura
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Patent number: 7699947Abstract: The invention relates to ultrahigh strength hot-rolled steel having a chemical composition consisting of, by weight: 0.05%?C?0.1% 0.7%?Mn?1.1% 0.5%?Cr?1.0% 0.05%?Si?0.3% 0.05%?Ti?0.1% Al?0.07% S?0.03% P?0.05% the remainder comprising iron and impurities resulting from the production thereof. Moreover, the inventive steel has a bainitic-martensitic structure which can contain up to 5% ferrite. The invention also relates to a method of producing bands of said steel.Type: GrantFiled: January 14, 2004Date of Patent: April 20, 2010Assignee: USINORInventors: Mireille Seux, Christophe Issartel, Fabienne Roumegoux
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Publication number: 20100089505Abstract: The present invention provides a method for manufacturing the hot-rolled sheet, which includes: a step A including a first rolling in which a steel sheet containing 0.04-0.20% C, 0.01-2.0% Si, 0.5-3.0% Mn by mass, and the reminder being Fe and inevitable impurities, is rolled by successive multi-pass rolling at a total rolling reduction of 80% or more while keeping the steel sheet at temperatures not lower than the para-equilibrium transformation temperature Ae3; a step B including a second rolling in which a single-pass rolling is carried out at a rolling reduction of 30-55% when an entry side temperature is not lower than the para-equilibrium transformation temperature Ae3; a step C including a third rolling in which a single-pass rolling is carried out at a rolling reduction of 35-70% when an entry side temperature is set within a predetermined range; and a step D in which within 0.2 seconds after the third rolling, the rolled sheet is cooled at a cooling rate of 600 degree C.Type: ApplicationFiled: February 2, 2007Publication date: April 15, 2010Inventors: Suguhiro Fukushima, Manabu Eto, Tamotsu Sasaki, Kaori Kawano, Masayuki Wakita
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Publication number: 20100084054Abstract: The present invention provides high strength hot rolled steel plate for line-pipes superior in low temperature toughness, and a method of production of the same, containing, by mass %, C: 0.01 to 0.1%, Si: 0.05 to 0.5%, Mn: 1 to 2%, P: ?0.03%, S: ?0.005%, O: ?0.003%, Al: 0.005 to 0.05%, N: 0.0015 to 0.006%, Nb: 0.005 to 0.08%, and Ti: 0.005 to 0.02%, where N?14/48×Ti>0% and Nb—93/14×(N?14/48×Ti)>0.005%, and a balance of Fe and unavoidable impurities, said steel plate characterized in that its microstructure is a continuously cooled transformed structure, a reflected X-ray intensity ratio {211}/{111} of the {211} plane and {111} plane parallel to the plate surface in the texture at the center of plate thickness is 1.1 or more, and an in-grain precipitate density of the precipitates of Nb and/or Ti carbonitrides is 1017 to 1018/cm3.Type: ApplicationFiled: February 29, 2008Publication date: April 8, 2010Inventors: Tatsuo Yokoi, Masanori Minagawa, Takuya Hara, Osamu Yoshida, Hiroshi Abe
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Publication number: 20100065166Abstract: A steel pipe with excellent expandability, comprises, by mass %, C: 0.1 to 0.45%, Si: 0.3 to 3.5%, Mn: 0.5 to 5%, P: less than or equal to 0.03%, S: less than or equal to 0.01%, soluble Al: 0.01 to 0.8% (more than or equal to 0.1% in case Si content is less than 1.5%), N: less than or equal to 0.05%, O: less than or equal to 0.01%, and balance being Fe and impurities, having a mixed microstructure comprising ferrite and one or more selected from fine pearlite, bainite and martensite, and has a tensile strength of more than or equal to 600 MPa and a uniform elongation satisfying the following formula u-el?28?0.0075 TS, wherein u-el is uniform elongation (%) and TS is tensile strength (MPa).Type: ApplicationFiled: October 7, 2009Publication date: March 18, 2010Inventors: Kunio Kondo, Yuji Arai
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Publication number: 20100032062Abstract: The present invention provides a steel plate having a low welding crack susceptibility and a yield strength of 800 MPa and a manufacturing method for the same. The steel plate having a low welding crack susceptibility comprises the following chemical components (wt. %: percent by weight): C: 0.03-0.08 wt. %, Si: 0.05-0.70 wt. %, Mn: 1.30-2.20 w.t %, Mo: 0.10-0.30 wt. %, Nb: 0.03-0.10 wt. %, V: 0.03-0.45 wt. %, Ti: 0.002-0.040 wt. %, Al: 0.02-0.04 wt. %, B: 0.0010-0.0020 wt. %, the balance being Fe and unavoidable impurities, and the welding crack susceptibility index meets the following formula: Pcm?0.20%. The thermo-mechanical controlled rolling and cooling processes is used to obtain an ultrafine bainite batten matrix structure, which increases the intensity, plasticity and toughness of the steel plate. The steel plate with a low welding crack susceptibility of the present invention has a yield strength of greater than 800 MPa, a tensile strength of greater than 900 MPa, a Charpy impact energy Akv (?20° C.Type: ApplicationFiled: October 24, 2008Publication date: February 11, 2010Applicant: BAOSHAN IRON & STEEL CO., LTD.Inventors: Liandeng Yao, Xiaoting Zhao, Sixin Zhao
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Publication number: 20090277544Abstract: A high-tensile strength welded steel tube has excellent formability and torsional fatigue endurance after being formed into cross-sectional shape and then stress-relief annealed. A steel material used has a composition which contains C, Si, Al, 1.01% to 1.99% Mn, 0.041% to 0.150% Ti, 0.017% to 0.150% Nb, P, S, N, and O such that the sum of the content of Ti and that of Nb is 0.08% or more, the content of each of C, Si, and Al being within an appropriate range, the content of each of P, S, N, and O being adjusted to a predetermined value or less.Type: ApplicationFiled: June 19, 2007Publication date: November 12, 2009Applicant: JFE Steel Corporation, a corporation of JapanInventors: Shunsuke Toyoda, Masatoshi Aratani, Yoshikazu Kawabata, Yuji Hashimoto, Koji Suzuki, Kei Sakata, Makio Gunji, Akio Sato, Tetsuro Sawaki
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Publication number: 20090277547Abstract: A high strength steel sheet with both excellent elongation and stretch-flanging performance is provided. The high strength steel sheet of the present invention comprises, in percent by mass, C: 0.05 to 0.3%, Si: 0.01 to 3.0%, Mn: 0.5 to 3.0%, Al: 0.01 to 0.1%, and Fe and inevitable impurities as the remainder, and has a structure mainly composed of tempered martensite and annealed bainite. The space factor of the tempered martensite is 50 to 95%, the space factor of the annealed bainite is 5 to 30%, and the mean grain size of the tempered martensite is 10 ?m or smaller in terms of the equivalent of a circle diameter. The steel sheet has a tensile strength of 590 MPa or higher.Type: ApplicationFiled: July 13, 2007Publication date: November 12, 2009Applicant: KABUSHIKI KAISHA KOBE SEIKO SHOInventors: Kenji Saito, Tomokazu Masuda, Masaaki Miura, Yoichi Mukai, Shushi Ikeda
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Publication number: 20090252641Abstract: A steel sheet contains, in terms of percent by mass, C: 0.01 to 0.2%, Si: 2.0% or less, and Mn: 3.0% or less and has a martensite phase as dominant phase and ferrite with a grain size of 20 ?m or less as a second phase. The ferrite is contained in area ratio of 1% to 30% and the amount of solute carbon being 0.01 percent by mass of more. The steel sheet can provide a hot-rolled steel sheet suitable for automobile steel sheet, i.e., has excellent press workability and excellent strain aging property whereby the tensile strength significantly increases by heat treatment at about the same temperature as typical baking process after the press-working. Moreover, hardening of the ferrite phase improves the fatigue strength after the strain aging.Type: ApplicationFiled: March 29, 2006Publication date: October 8, 2009Applicant: JFE Steel Corporation a corporation of JapanInventors: Toru Hoshi, Saiji Matsuoka
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Publication number: 20090178739Abstract: It is an object of the present invention to provide a ferromagnetic Fe-based alloy having a large reversible strain obtained by application and removal of a magnetic field gradient. The Fe-based alloy contains one or two or more types selected from Al: 0.01 to 11%, Si: 0.01 to 7% and Cr: 0.01 to 26%, or Al: 0.01 to 11%, Si: 0.01 to 7%, Cr: 0.01 to 26% and Ni: 35 to 50%. A twin crystal interface is introduced by working the Fe-based alloy at a working rate: 10% or more. An area ratio of the twin crystal interface to a crystal grain boundary is 0.2 or more. One or two or more types of Ti: 0.01 to 5%, V: 0.01 to 10%, Mn: 0.01 to 5%, Co: 0.01 to 30%, Ni: 0.01 to 10%, Cu: 0.01 to 5%, Zr: 0.01 to 5%, Nb: 0.01 to 5%, Mo: 0.01 to 5%, Hf: 0.01 to 5%, Ta: 0.01 to 5%, W: 0.01 to 5%, B: 0.001 to 1%, C: 0.001 to 1%, P: 0.001 to 1% and S: 0.001 to 1% may be added to the Fe-based alloy if needed.Type: ApplicationFiled: February 20, 2009Publication date: July 16, 2009Applicant: JAPAN SCIENCE AND TECHNOLOGY AGENCYInventors: Kiyohito Ishida, Ryosuke Kainuma, Katunari Oikawa, Yuji Sutou, Toshihiro Omori, Keisuke Ando
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Publication number: 20090173415Abstract: A steel sheet excellent in FB performance-and also excellent in fabrication performance after FB working and a manufacturing method of the same are provided. The steel sheet is a steel sheet having a composition containing from 0.1 to 0.5% of C, not more than 0.5% of Si and from 0.2 to 1.5% of Mn in terms of % by mass, with P and S being adjusted at proper ranges, and having a structure in which a ferrite has an average grain size of from 1 to 10 ?m, cementite has a spheroidization ratio of 80% or more, and of the cementite, an amount Sgb of ferrite intergranular cementite which is defined by the following expression (1): Sgb(%)={Son/(Son+Sin)}×100 (wherein Son represents a total occupied area of cementite present on the ferrite grain boundary of the cementite present per unit area; and Snin represents a total occupied area of cementite present in a ferrite grain of the cementite present per unit area) is 40% or more.Type: ApplicationFiled: January 29, 2007Publication date: July 9, 2009Applicant: JFE STEEL CORPORATIONInventors: Kazuhiro Seto, Takeshi Yokota, Nobuyuki Nakamura, Nobusuke Kariya
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Publication number: 20090126836Abstract: A high carbon hot-rolled steel sheet, as a hot-rolled spheroidizing annealed material, having both excellent stretch-flange formability and excellent homogeneity of hardness in the sheet thickness direction is provided by a manufacturing method having the steps of: hot-rolling a steel containing 0.2 to 0.7% C by mass at finishing temperatures of (Ar3 transformation point?20° C.) or above to prepare a hot-rolled sheet; cooling the hot-rolled sheet to temperatures of 650° C. or below at cooling rates from 60° C./s or larger to smaller than 120° C./s; coiling the hot-rolled sheet after cooling at coiling temperatures of 600° C. or below; and annealing the coiled hot-rolled sheet at annealing temperatures from 640° C. or larger to Ac1 transformation point or lower.Type: ApplicationFiled: June 19, 2006Publication date: May 21, 2009Inventors: Nobusuke Kariya, Norio Kanamoto, Hidekazu Ookubo, Yoshiharu Kusumoto, Takeshi Fujita
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Publication number: 20090107591Abstract: A high-tensile steel plate of low acoustic anisotropy and high weldability having yield stress of 450 MPa or greater and tensile strength of 570 MPa or greater and a process for producing the steel plate are provided. The steel has an Si content of 0.10% or less, thereby achieving a volume ratio of island martensite of 3% or less, contains Nb?0.025% and Ti?0.005% so as to satisfy 0.045%?[Nb]+2×[Ti]?0.105%, contains Nb, Ti, C and N in ranges such that the value of A=([Nb]+2×[Ti])×([C]+[N]×12/14) is 0.0022 to 0.0055, and has a steel structure wherein bainite volume ratio is 30% or more and pearlite volume ratio is less than 5%.Type: ApplicationFiled: November 8, 2006Publication date: April 30, 2009Inventors: Manabu Hoshino, Masaaki Fujioka, Yoichi Tanaka, Tatsuya Kumagai
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Publication number: 20090095381Abstract: A high tensile steel sheet having 980 MPa or higher tensile strength with excellent elongation and stretch-flange formability, suitable for the press-forming of complex cross sectional shape such as automobile parts, is manufactured by adjusting the steel to consist essential of a ferrite single phase structure, to precipitate carbide containing Ti, Mo, and V, of smaller than 10 nm of average particle size, in dispersed state, and to have an average composition of the carbide containing Ti, Mo, and V satisfying [V/(Ti+Mo+V)?0.3 (atomic ratio].Type: ApplicationFiled: August 3, 2006Publication date: April 16, 2009Applicant: JFE STEEL CORPORATIONInventors: Tamako Ariga, Takeshi Yokota, Akio Kobayashi, Kazuhiro Seto
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Publication number: 20090095383Abstract: The present invention provides a fine grain surface layer steel part having a high proof strength ratio equal to or higher than that of conventional quenched and tempered materials, that is, a fine grain surface layer steel part containing, by mass %, C: 0.45% to 0.70%, Nb: 0.01% to 0.60%, Si: 0.10% to 1.50%, Mn: 0.40% to 2.0%, P: 0.10% or less, S: 0.001% to 0.15%, and N: 0.003% to 0.025% and having a balance of Fe and unavoidable impurities, where the surface layer and inside at all or part of the part have structures of different average particle sizes of ferrite crystal grains surrounded by high angle grain boundaries of a misorientation angle of 15 degrees or more and a method of production of that part comprising warm forging locations where strength is required to a predetermined shape at 1000° C. to 800° C. during which working so as to give an equivalent strain of 1.5 or more.Type: ApplicationFiled: July 27, 2007Publication date: April 16, 2009Applicant: Nippon Steel CorporationInventors: Shinya Teramoto, Hiromasa Takada
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Publication number: 20090050243Abstract: A high-strength hot-rolled steel sheet containing C: 0.05 to 0.15%, Si: no more than 1.50% (excluding 0%), Mn: 0.5 to 2.5%, P: no more than 0.035% (excluding 0%), S: no more than 0.01% (including 0%), Al: 0.02 to 0.15%, and Ti: to 0.2%, which is characterized in that its metallographic structure is composed of 60 to 95 vol % of bainite and solid solution-hardened or precipitation-hardened ferrite (or ferrite and martensite) and its fracture appearance transition temperature (vTrs) is no higher than 0° C. as obtained by impact tests.Type: ApplicationFiled: March 22, 2006Publication date: February 26, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho(Kobe Steel Ltd.)Inventors: Motoo Satou, Tetsuo Soshiroda
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Publication number: 20090039714Abstract: A low-cost, thermomechanical method for manufacturing [001] textured FeGa alloys is described. The method includes hot rolling a FeGa cast ingot to break down the cast structure, a two-stage warm rolling with an intermediate anneal, and then a final texture anneal that resulted in recrystallization and a recrystallization-induced texture. The FeGa ingot contains a grain growth agent that was used to restrain grain growth of the FeGa material in the undesired crystallographic direction. A protective steel sheath can be placed around the FeGa material during processing to avoid direct contact of the FeGa and the rolls during the hot and warm rolling process steps and also avoid oxidation of the alloy ingot. FeGa alloys with a very strong [001] texture and a large magnetostriction along [001] crystallographic direction were obtained using this method. FeGaBe alloys and new methods for making them are also described.Type: ApplicationFiled: March 3, 2006Publication date: February 12, 2009Inventors: Pinai Mungsantisuk, Sivaraman Guruswanmy, Nakorn Srisukhumbowornchai
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Publication number: 20090032148Abstract: There is provided a high-strength hot rolled steel sheet excellent in phosphatability, wherein a maximum depth (Ry) of pits and bumps, existing on a surface thereof, is not less than 10 ?m, and an average interval (Sm) of the pits and the bumps is not more than 30 ?m, meeting either a requirement for a load length ratio (tp40) of the pits and the bumps on the surface at not more than 20%, or a requirement for a difference between a load length ratio (tp60) and the load length ratio (tp40), at not less than 60%, or both thereof. The high-strength hot rolled steel sheet is capable of exhibiting stable and excellent phosphatability even if Mo highly effective for reinforcement in strength is added thereto in expectation of a higher strength.Type: ApplicationFiled: March 30, 2006Publication date: February 5, 2009Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd)Inventors: Shinji Kozuma, Masahiro Nomura, Ikuro Hashimoto
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Publication number: 20090025839Abstract: Accordingly to an exemplary embodiment of the present invention, a high tensile strength, refractory steel can be provided which comprises, in mass %, approximately C: 0.04 to 0.14%, Si: 0.50% or less, Mn: 0.50 to 2.00%, P: 0.020% or less, S: 0.010% or less, Nb: 0.01 to 0.05%, Mo: 0.30% or more and less than 0.70%, Al: 0.060% or less, N: 0.0010 to 0.0060%, and the balance consisting of iron and unavoidable impurities. For example, a weld crack sensitive composition PCM can be defined by the following equation may be about 0.25% or less: PCM=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B. An area fraction of polygonal ferrite or pseudo polygonal ferrite in a ¼ thick position in the plate thickness direction of the steel plate of the final rolling product is about 10% or less.Type: ApplicationFiled: March 3, 2006Publication date: January 29, 2009Applicant: Nippon Steel CorporationInventors: Yoshiyuki Watanabe, Ryuuji Uemori, Kiyoshi Ishibashi, Kenichi Yoshii
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Publication number: 20090025835Abstract: The present invention provides high strength steel plate and high strength welded pipe excellent in ductile fracture characteristic and methods of production of the same, that is, high strength steel plate excellent in ductile fracture characteristic, and high strength welded pipe using that steel plate as a base material, having a tensile strength corresponding to the X100 class of the API standard, containing, by mass %, C: 0.01 to 0.5%, Si: 0.01 to 3%, Mn: 0.1 to 5%, P: 0.03% or less, and S: 0.03% or less and a balance of Fe and unavoidable impurities, having a microstructure comprised of, by area ratio, 1 to 60% of ferrite and the balance of bainite and martensite, having a maximum value of the {100} accumulation degree of the cross-section rotated 20 to 50° from the plate thickness cross-section about the rolling direction as an axis of 3 or less, and having plate thickness parallel cracks measured by ultrasonic flaw detection of less than 1 mm.Type: ApplicationFiled: April 19, 2005Publication date: January 29, 2009Inventors: Takuya Hara, Yasuhiro Shinohara, Hitoshi Asahi, Yoshio Terada
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Publication number: 20080308193Abstract: A graphite-containing, heat-resistant cast iron for exhaust equipment members used at temperatures exceeding 800° C., comprising 3.5-5.6% of Si and 1.2-15% of W on a weight basis, and having intermediate layers, in which W and Si are concentrated, in the boundaries of graphite particles and a matrix. An exhaust equipment member formed by this heat-resistant cast iron has an AC transformation point is 840° C. or higher when measured from 30° C. at a temperature-elevating speed of 3° C./minute, and a thermal cracking life of 780 cycles or more in a thermal fatigue test, in which heating and cooling are conducted under the conditions of an upper-limit temperature of 840° C., a temperature amplitude of 690° C. and a constraint ratio of 0.25.Type: ApplicationFiled: November 9, 2004Publication date: December 18, 2008Inventors: Yoshio Igarashi, Seiichi Endo, Masahiro Miyake, Tsunehiro Kawata
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Publication number: 20080302450Abstract: The invention discloses an object comprising at least one part made of steel, the composition of which comprises, the contents being expressed by weight, carbon with a content of between 0.005 and 0.27%, manganese between 0.5 and 1.6%, silicon between 0.1 and 0.4%, chromium in a content of less than 2.5%, Mo in a content of less than 1%, optionally one or more elements chosen from nickel, copper, aluminum, niobium, vanadium, titanium, boron, zirconium and nitrogen, the balance being iron and impurities resulting from the smelting, said steel part including at least one zone welded by a high-energy-density beam, characterized in that said welded zone has a microstructure consisting of 60 to 75% self-tempered martensite and, to complement this, 40 to 25% lower bainite, and preferably 60 to 70% self-tempered martensite and, to complement this, 40 to 30% lower bainite.Type: ApplicationFiled: June 21, 2005Publication date: December 11, 2008Applicant: ARCELOR FranceInventor: Dominique Kaplan
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Publication number: 20080295920Abstract: The present invention provides a high tension steel plate of a tensile strength of 570 MPa or more with a small acoustic anisotropy and with excellent weldability tensile strength and a method of production of steel plate predicated on the high productivity accelerated cooling stop process, which steel sheet is a high tension steel plate with a value of 0.045%?Nb+2Ti?0.105%, A=(Nb+2Ti)×(C+N×12/14) satisfying 0.0025 to 0.0055 and with a steel composition containing bainite in an amount of 30 vol % or more and pearlite+martensite-austenite constituent (MA) in an amount of less than 5 vol %. The steel is heated to 1200° C. or more, rough rolled at 1020° C. or more, then rolled at a cumulative reduction rate from over 920° C. to less than 1020° C. of 15% or less and a cumulative reduction rate from 860 to 920° C. of 20 to 50%, then starting accelerated cooling giving a cooling rate of 2 to 30° C./sec at 800° C. or more, stopping the accelerated cooling at 600 to 700° C., then cooling by 0.4° C./sec or less.Type: ApplicationFiled: February 14, 2005Publication date: December 4, 2008Inventors: Tatsuya Kumagai, Masaaki Fujioka
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Publication number: 20080295924Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.Type: ApplicationFiled: August 4, 2008Publication date: December 4, 2008Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
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Publication number: 20080271823Abstract: Coating steel strips comprising, in % by weight, C: ?1.6%, Mn: 6-30%, Al: ?10%, Ni: ?10%, Cr: ?10%, Si: ?8%, Cu: ?3%, Nb: ?0.6%, Ti: ?0.3%, V: ?0.3%, P: ?0.1%, B: ?0.01%, the rest being iron and unavoidable impurities, and a method of forming steel strips are described. Up to now, such steel strips were not adequately coatable, with a metal coating ensuring outstanding corrosion-resistance and good welding properties. This is ensured by applying an aluminium layer to the steel strip before final annealing and applying the metal coating to said aluminium layer after final annealing.Type: ApplicationFiled: February 1, 2006Publication date: November 6, 2008Applicant: Thyssenkrupp Steel AGInventors: Harald Hofmann, Manfred Meurer, Bernd Schuhmacher, Slavcho Topalski
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Patent number: 7442264Abstract: The use is described, in the fabrication of apparatus and equipment used in refining and in petrochemicals (for example furnace, reactor or line elements), of a steel composition comprising: at most 0.25% C; more than 1% up to 10% Mn; 1.5% to 5% Si; at most 0.03% P; at most 0.03% S; 4% to 10% Cr; 0.5% to 2% Mo; at most 0.40% V; and at most 0.10% N; the complement to 100% being essentially iron. Steels comprising: at most 0.15% C; more than 2% up to 10% Mn; 1.5% to 5% Si; at most 0.03% P; at most 0.03% S; 4% to 10% Cr; more than 0.5% up to 2% Mo; at most 0.40% V; and at most 0.10% N; the complement to 100% being essentially iron; are themselves novel.Type: GrantFiled: February 27, 2004Date of Patent: October 28, 2008Assignee: Institute Francais du PetroleInventors: Francois Ropital, Xavier Longaygue
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Publication number: 20080251160Abstract: A high-strength cold-rolled steel sheet excellent in uniform elongation, including in percent by mass: 0.10-0.28% of C; 1.0-2.0% of Si; and 1.0-3.0% of Mn, and the structures of the same having the space factors below to the entire structure: 30-65% of bainitic ferrite; 30-50% of polygonal ferrite; and 5-20% of residual austenite.Type: ApplicationFiled: March 28, 2006Publication date: October 16, 2008Applicants: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd), Shinshu Tlo Co., Ltd.Inventors: Hiroshi Akamizu, Yoichi Mukai, Shushi Ikeda, Koichi Sugimoto
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Publication number: 20080251161Abstract: A high-strength cold-rolled steel sheet exhibiting an excellent strength-workability balance, including in percent by mass: 0.10-0.25% of C; 1.0-2.0% of Si; 1.5-3.0% of Mn; 0.01% or less (not including 0%) of P; 0.005% or less (not including 0%) of S; 0.01-3.0% of Al; and remaining part consisting of iron and inevitable impurities, wherein the space factor of bainitic ferrite to the entire structure is 70% or more, the space factor of residual austenite to the entire structure is 5-20%, the hardness (HV) is 270 or greater, and the half-value width of an X-ray diffraction peak on a (200)-surface of ?-iron is 0.220 degrees or smaller.Type: ApplicationFiled: March 29, 2006Publication date: October 16, 2008Applicants: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), Shinshu TLO Co., Ltd.Inventors: Takahiro Kashima, Yoichi Mukai, Hiroshi Akamizu, Koichi Sugimoto
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Publication number: 20080223491Abstract: Disclosed is a hot rolled steel sheet which contains C, Si, Mn, Al, Ti, N, and S. The C, Ti, N, and sulfur contents satisfy the following condition (1), and the Si and Mn contents satisfy the following condition (2): [C]—{[Ti]-(48/14)x[N]-(48/32)x[S]}/4?0.01 ??(1) 0.20?([Si]/[Mn])?0.85 ??(2) in which the symbol [X] represents the content (percent by mass) of the element X, and the steel sheet has a microstructure having an area percentage of bainitic ferrite of 90% or more, an area percentage of martensite of 5% or less, and an area percentage of bainite of 5% or less, based on the area of an observed field. This steel sheet excels in properties demanded in press working, such as shape freezing ability, hole-expandability, and bendability, even though it has a high tensile strength of 980 MPa or more.Type: ApplicationFiled: February 26, 2008Publication date: September 18, 2008Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd.)Inventor: Kazuya KIMIJIMA
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Publication number: 20080110535Abstract: The invention provides a high tensile strength steel material having a tensile strength of 600 MPa, which is excellent in delayed fracture resistance property, and a method of manufacturing the steel material. As means for this, a steel material contains, in mass percent, C of 0.02 to 0.25%, Si of 0.01 to 0.8%, Mn of 0.5 to 2.0%, Al of 0.005 to 0.1%, N of 0.0005 to 0.008%, P of 0.03% or less, and S of 0.03% or less. In addition, the steel material contains at least one element selected from Mo, Nb, V, and Ti, and contains at least one of Cu, Ni, Cr, W, B, Ca, REM and Mg, as needed. The remainder includes Fe and inevitable impurities. In addition, in the steel material, precipitates having an average grain size of 20 nm or less, which contains at least one of Mo, Nb, V and Ti, are contained in steel in the number of at least 5 per 250000 nm2, and a microstructure includes residual austenite in a volume fraction of 0.5 to 5%. When Ca to be added is specified to be 0.0010% to 0.Type: ApplicationFiled: May 29, 2006Publication date: May 15, 2008Inventors: Kenji Oi, Akihide Nagao, Kenji Hayashi
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Publication number: 20040037731Abstract: By limiting steel compositions with respect to special components and controlling contents of Ti, Zr and S in a steel to a suitable range, fine Ti and Zr sulfides are generated so that a cast steel having excellent internal quality and machinability after casting can be ensured. Then, by casting this cast steel a mold having excellent machinability, whose internal quality as cast is comparable to that of a forged steel product, can be produced. Therefore, the mold of the present invention can be widely applied to use, which severely requires excellent surface properties in products for deep-engraving in which a worked surface reaches the internal portion of the section material or for finishing.Type: ApplicationFiled: September 2, 2003Publication date: February 26, 2004Inventors: Yasutaka Okada, Koji Watari
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Publication number: 20040031547Abstract: The present invention provides a high tensile strength hot-rolled steel sheet having superior strain aging hardenability, which has high formability and stable quality characteristics, and in which satisfactory strength is obtained when the steel sheet is formed into automotive components, thus enabling the reduction in weight of automobile bodies. Specifically, a method for producing a high tensile strength hot-rolled steel sheet having superior strain aging hardenability with a BH of 80 MPa or more, a &Dgr;TS of 40 MPa or more, and a tensile strength of 440 MPa or more includes the steps of heating a steel slab to 1,000° C. or more, the steel slab containing, in percent by mass, 0.15% or less of C, 2.0% or less of Si, 3.0% or less of Mn,. 0.08% or less of P, 0.02% or less of S, 0.02% or less of Al, 0.0050% to 0.0250% of N, and optionally 0.1% or less in total of at least one of more than 0.02% to 0.1% of Nb and more than 0.02% to 0.1% of V, the ratio N (mass %)/Al (mass %) being 0.Type: ApplicationFiled: August 18, 2003Publication date: February 19, 2004Applicant: Kawasaki Steel CorporationInventors: Akio Tosaka, Sinjiro Kaneko, Yoichi Tominaga, Noriyuki Katayama, Nobutaka Kurosawa, Kei Sakata, Osamu Furukimi
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Patent number: 6623571Abstract: This invention relates to the synthesis of a new generation of metastable aluminum-titanium (Al—Ti) alloys and the process of making them. The preparation method used is a combination process incorporating the advantages of conventional casting and spray techniques. The process is a low cost process. The aluminum-titanium materials made in this invention contain titanium in both the reacted and unreacted form. The results were confirmed using microstructural and x-ray diffraction studies. The presence of phases clearly indicate the metastable nature of these materials in accordance with the equilibrium phase diagram established for Al—Ti system. The Al—Ti materials can be made in the dimensions suitable for structural applications at ambient and elevated temperatures and as control materials for synthesis of more dilute equilibrium Al—Ti materials using conventional techniques such as casting.Type: GrantFiled: April 4, 2001Date of Patent: September 23, 2003Assignee: National University of SingaporeInventor: Manoj Gupta
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Patent number: 6617050Abstract: An alloy for golf club head include by weight 25 to 31 wt % manganese, 6.3 to 7.8 wt % aluminum, 0.65 to 0.85 wt % carbon and 5.5 to 9.0 wt % chromium, and the balance being iron. Additions of 0.8 to 1.5 wt % silicon, 2.0 to 5.0 wt % titanium, or 0.5 to 1.0 wt % molybdenum are optionally included in the alloy. Due to the chromium, titanium and molybdenum, the alloy has a good resistance to corrosion, a good finished surface quality after being forged at a temperature from 800° C. to 1050° C. A combination of high ductility and high tensile strength is achieved after the alloy has been treated at a temperature from 980° C. to 1080° C. for 1 to 24 hours.Type: GrantFiled: October 19, 2001Date of Patent: September 9, 2003Assignee: O-Ta Precision Casting Co., Ltd.Inventor: Chih-Yeh Chao
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Patent number: 6586117Abstract: A steel for forming a high strength steel sheet contains, in mass %, C: at most 0.04%, Si: at most 0.4%, Mn: 0.5-3.0%, P: at most 0.15%, S: at most 0.03%, Al: at most 0.50%, N: at most 0.01%, and Mo: 0.01-1.0%. Steel sheet formed from the steel is suitable for use as automotive panels.Type: GrantFiled: October 19, 2001Date of Patent: July 1, 2003Assignee: Sumitomo Metal Industries, Ltd.Inventors: Shigeki Nomura, Hiroyuki Nakagawa, Yoshiaki Nakazawa
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Patent number: 6559573Abstract: A shaft 2 of a spindle motor is composed of a steel material including 0.20 wt % of C, 0.35 wt % of Si, 8.00 wt % of Mn, higher than 0 and equal to or less than 0.05 wt % of P, 0.15 wt % of S, higher than 0 and equal to or less than 2.00 wt % of Ni and 14.00 wt % of Cr and the remainder substantially being Fe. The steel material has corrosion resistance with no plating requirement and wear resistance with no need for a heat treatment and/or a soft nitriding. Further, when considering a conventionally employed stainless steel, Pb has been frequently added thereto in order to improve machinability. On the contrary, the steel material according to the embodiments of the present invention is Pb-free material. Since the shaft of the spindle motor is manufactured by a material high in its wear resistance, corrosion resistance and workability and in which the generation of the out gas of sulfur and sulfur compounds is suppressed low, the qualities of electronic devices and communication devices, etc.Type: GrantFiled: March 16, 2001Date of Patent: May 6, 2003Assignee: Minebea Co., Ltd.Inventors: Akio Okamiya, Toshisada Koyama
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Patent number: 6524726Abstract: Disclosed is a cold-rolled steel sheet excellent in formability, panel shapeability and dent-resistance, comprising 0.005 to 0.015% by weight of C, 0.01 to 0.2% by weight of Si, 0.2 to 1.5% by weight of Mn, 0.01 to 0.07% by weight of P, 0.006 to 0.015% by weight of S, 0.01 to 0.08% by weight of sol. Al, not higher than 0.004% by weight of N (N≦0.004%), not higher than 0.003% by weight of O (O≦0.003%), 0.04 to 0.23% by weight of Nb, 1.0≦(Nb %×12)/(C %×93)≦3.0, and a balance of Fe and unavoidable impurities, said cold-rolled steel sheet meeting the relationship given below: exp(&egr;)×(5.29×exp(&egr;)−4.19)≦&sgr;/&sgr;0.2≦exp(&egr;)×(5.64×exp(&egr;)−4.49) where 0.002<&egr;≧0.096, &egr; represents a true strain, &sgr;0.2 represents a 0.2% proof stress, and &sgr; represents a true stress relative to &egr;.Type: GrantFiled: December 23, 1999Date of Patent: February 25, 2003Assignee: NKK CorporationInventors: Fusato Kitano, Masaya Morita, Yoshihiro Hosoya, Takeshi Fujita, Tadashi Inoue, Masahiro Iwabuchi, Takeo Ishii
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Publication number: 20030034100Abstract: Steel strapping and a method of manufacturing steel strapping are disclosed. The steel strapping has the following composition in wt % and a microstructure including a matrix of recovery-annealed cold worked ferrite containing martensite and carbides dispersed through the matrix. 1 C: up to 0.2 Mn: up to 2.0 Si: 0.2-0.4 Ti: 0.025-0.045 V: 0.05-0.07 Cr: up to 0.25 Ni: up to 0.30 Mo: up to 0.10 N: up to 0.005 Cu: up to 0.20 Al: up to 0.08 Nb: up to 0.005 P: up to 0.035 S: up to 0.020 Balance iron and incidental impurities.Type: ApplicationFiled: August 2, 2001Publication date: February 20, 2003Inventors: Jeffery W. Doonan, Peter Ivan Unicomb, Robert K. Armstrong
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Patent number: 6506266Abstract: A composition for steel used for tires or solid wheels of rail vehicles, which composition provides improved properties, in terms of wear, crack susceptibility, ability to withstand thermal loads, homogenous microstructural properties and suitability for high dynamic loads, as compared to standard steels used for tires or solid wheels of rail vehicles. The steel is a modification of AISI S2 steel previously only used for antifriction bearings. The elements of the composition and their presence by percentage of total mass of the steel and ratios of the presence of various elements are disclosed.Type: GrantFiled: January 28, 2000Date of Patent: January 14, 2003Assignee: Fag Oem und Handel AGInventors: Edgar Pröschel, Heinz Stangner
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Publication number: 20020162613Abstract: Disclosed herein is a high-strength hot-rolled steel sheet superior in stretch-flanging properties and fatigue properties which comprises (in mass %) 0.01-0.10% C, less than 2% Si (including 0%), 0.5-2% Mn, less than 0.08% P (including 0%), less than 0.01% S (including 0%), less than 0.01% N (including 0%), 0.01-0.1% Al, and at least one of 0.1-0.5% Ti and less than 0.8% Nb (including 0%), with the granular bainitic structure accounting for more than 80% (by area) in its sectional metallographic structure. Disclosed also herein is a process for producing said steel sheet.Type: ApplicationFiled: February 27, 2001Publication date: November 7, 2002Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takahiro Kashima, Shunichi Hashimoto
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Patent number: 6423426Abstract: A steel sheet having a composition comprising C: 0.05-0.20 mass %, Si: 0.3-1.8 mass %, Mn: 1.0-3.0 mass %, Fe of the balance and inevitable impurities is subjected to a primary step of primary heat treatment and subsequent rapid cooling to Ms point or lower, a secondary step of secondary heat treatment and subsequent rapid cooling, and a tertiary step of galvanizing treatment and rapid cooling, so as to turn the structure of the steel sheet into a composite structure of 20% or more by volume of tempered martensite, 2% or more by volume of retained austenite, ferrite and a low-temperature transformation phase. A galvanized layer is deposited on the surface of the steel sheet. It is preferred to cool the steel sheet to 300° C. at a cooling rate of 5 ° C./sec. or more after the galvanizing treatment. After the galvanizing treatment, alloying treatment may be conducted.Type: GrantFiled: March 5, 2001Date of Patent: July 23, 2002Assignee: Kawasaki Steel CorporationInventors: Takashi Kobayashi, Kei Sakata, Akio Shinohara
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Patent number: 6410163Abstract: The present invention provides a high strength thin excellent workability and galvanizability, having a composition comprising from 0.01 to 0.20 wt. % C, up to 1.0 wt. % Si, from 1.0 to 3.0 wt. % Mn, up to 0.10 wt. % P, up to 0.05 wt. % S, up to 0.10 wt. % Al, up to 0.010 wt. % N, up to 1.0 wt. % Cr, from 0.001 to 1.00 wt. % Mo, and the balance Fe and incidental impurities, wherein a band structure comprising a secondary phase has a thickness satisfying the relation Tb/T≦0.005 (where, Tb: average thickness of the band structure in the thickness direction of steel sheet; T: steel sheet thickness), and a manufacturing method thereof, and a manufacturing method of a high strength hot-dip galvanized steel sheet or a high strength galvannealed steel sheet applying hot-dip galvanizing or further galvannealing, and giving an excellent workability, a high tensile strength, and excellent galvanizability, coating adhesion and corrosion resistance.Type: GrantFiled: May 30, 2000Date of Patent: June 25, 2002Assignee: Kawasaki Steel CorporationInventors: Yoshitsugu Suzuki, Kazunori Osawa, Chiaki Kato, Yoichi Tobiyama, Kei Sakata, Osamu Furukimi, Akio Shinohara
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Patent number: 6361740Abstract: A high-damping, corrosion resistant and substantially non-magnetic material having high damping properties has been developed for use in dynamic applications, specifically, a disk drive suspension arm and load beam. A disk drive assembly includes a disk having a readable and writeable surface, a motor operable for rotating the disk, and an actuator assembly that includes a transducer mounted on a load beam. The actuator assembly is operable for positioning the transducer in transducing relationship with the surface of the disk. When the disk spins, shear forces create turbulence in the fluidic medium adjacent to the surface of the disk. The turbulence exerts unbalanced and variable forces on the load beam, inducing vibrational motion therein. If the vibrational energy stored in the load beam is not quickly damped, the surface of the disk, load beam or transducer can be damaged. The present invention discloses alloy compositions of the form (14-21)Mn, (10-13)Cr, (0-6)Si, (4-10)Ni, (0-6)Co, and (0-0.Type: GrantFiled: May 19, 2000Date of Patent: March 26, 2002Assignee: Intri-Plex Technologies, Inc.Inventors: Mehrooz Zamanzadeh, Ronald Noebe
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Publication number: 20020005234Abstract: The present invention describes an ultra-low carbon bake hardenable galvanized or galvannealed steel product, having a higher yield strength at the temperature of the molten zinc bath while maintaining a low yield strength and excellent bake hardening properties in a skinpassed condition, BH0 being higher than 35 MPa and BH2 higher than 40 MPa (GI) and BH0>20 MPa and BH2>30 MPa (GA), as well as having a superior paint appearance after stamping and painting. The content in the steel composition of the Ti is comprised between 3,42 N and 3,42 N+60 ppm for a fixed nitrogen content (N), and the Nb-content, comprised between 50 ppm and 100 ppm, is fixed so that no substantial precipitation of niobium carbides will occur during the process.Type: ApplicationFiled: December 22, 2000Publication date: January 17, 2002Inventors: Sven Vandeputte, Serge Claessens
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Publication number: 20010025674Abstract: A railroad rail of a steel alloy having a pearlitic microstructure, which rail has a good long-term serviceability, high ductility and high abrasion resistance of the working surface at the rail head, the rail being formed of a steel alloy having a chemical composition in weight % of 0.4 to 1.0 carbon, 0.1 to 1.2 silicon, 0.5 to 3.5 manganese, up to 1.5 chromium, optionally other alloy elements below 1 weight %, the rest being iron and impurities, and at least the rail head having a portion of fine pearlitic microstructure and a hardness between 340 HB and 425 HB down to a sufficient depth from the top surface, the arrangement and the extension of the portion of fine pearlitic microstructure in the rail cross section being even along the entire length of the rail.Type: ApplicationFiled: March 23, 2001Publication date: October 4, 2001Applicant: VOEST ALPINE SCHIENEN GmbH & Co.Inventors: Georg Prskawetz, Peter Pointner, Alfred Moser
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Patent number: 6112669Abstract: A lead-free projectile made from a composition containing about 5-25% by weight tungsten and more than about 97% by weight tungsten plus iron.Type: GrantFiled: June 5, 1998Date of Patent: September 5, 2000Assignee: Olin CorporationInventors: Brian Mravic, Peter W. Robinson
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Patent number: 5743972Abstract: A heavy-wall steel having a flange thickness of about 40 mm or more and possessing excellent strength, toughness, weldability, and seismic resistance capable of being used for structure members such as columns and beams of high-rise buildings. The heavy-wall steel has a tensile strength of about 490-690 MPa, a yield ratio of about 80% or less, and Charpy absorbed energy at 0.degree. C. of about 27 J or more at the center in terms of thickness of the flange portion in each of the rolling direction, the direction perpendicular to the rolling direction, and the plate-thickness direction.Type: GrantFiled: August 27, 1996Date of Patent: April 28, 1998Assignee: Kawasaki Steel CorporationInventors: Tatsumi Kimura, Kiyoshi Uchida, Fumimaru Kawabata, Keniti Amano, Takanori Okui
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Patent number: 5735974Abstract: A part of a light-water reactor, for example, a cladding for a light-water reactor has at least a portion made of an intermetallic compound, such as Ni.sub.3 Al, Ni.sub.2 Al.sub.3, TiAl, Ti.sub.3 Al, Pt.sub.2 Si, PtSi, FeAl.sub.2, CoAl, and MoSi.sub.2, thereby having limited irradiation degradation by fast neutrons, improved ductility and usability at high temperatures the intermetallic compound is produced by a process comprising a step of irradiating the intermetallic compound with at least one selected from the group consisting of a neutron, a light ion, and an electron. The intermetallic compound may contain a twin and a third additional element segregatedly present or forms a second phase at or near to a grain boundary.Type: GrantFiled: December 10, 1996Date of Patent: April 7, 1998Assignee: Japan Atomic Energy ResearchInventors: Akimichi Hishinuma, Katsumaro Fukai