Boron Or Beryllium Containing Patents (Class 420/106)
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Publication number: 20080247903Abstract: 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+0.5O×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: ApplicationFiled: June 17, 2008Publication date: October 9, 2008Inventors: Jean BEGUINOT, Jean-Georges Brisson
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Publication number: 20080199346Abstract: A weld metal of a high-strength Cr—Mo steel formed by shielded metal arc welding contains: 0.04 to 0.10% by mass C, 0.15 to 0.5% by mass Si, 0.5 to 1.0% by mass Mn, 2.00 to 3.25% by mass Cr, 0.9 to 1.2% by mass Mo, 0.01 to 0.03% by mass Nb, 0.2 to 0.7% by mass V, 0.003% by mass or below and above 0% by mass B, 0.02 to 0.05% by mass O, and the balance of Fe and inevitable impurities. A residual extracted by electrolytic extraction from only an unaffected zone of the weld metal contains precipitated Cr in a Cr content below 0.3% by mass, and precipitated Nb in a Nb content of 0.005% by mass or above.Type: ApplicationFiled: February 1, 2008Publication date: August 21, 2008Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Yoshitomi Okazaki, Ken Yamashita, Hirohisa Watanabe, Koichi Hosoi
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Publication number: 20080159901Abstract: Method for reducing the segregated seams of a steel which has high mechanical strength and high wear resistance and whose composition comprises by weight: 0.30%?C?1.42%; 0.05%?Si?1.5%; Mn?1.95%; Ni?2.9%; 1.1%?Cr?7.9%; 0.61%?Mo?4.4%; optionally V?1.45%, Nb?1.45%, Ta?1.45% and V+Nb/2+Ta/4?1.45% ; less than 0.1% of boron, less than 0.19% of (S+Se/2+Te/4), less than 0.01% of calcium, less than 0.5% of rare earths, less than 1% of aluminum, less than 1% of copper; the balance being iron and impurities resulting from the production operation. The composition further complies with: 800?D?1150 with D=540(C)0.25+245 (Mo+3 V+1.5 Nb+0.75 Ta)0.30+125 Cr0.20+15.8 Mn+7.4 Ni+18 Si. According to the method, the molybdenum is completely or partially replaced with double the proportion of tungsten so that W>0.21%, and Ti, Zr, C are adjusted so that, after adjustment, Ti+Zr/2?0.2 W, (Ti+Zr/2)×C?0.07, Ti+Zr/2?1.49% and D is unchanged at approximately 5%. Steel obtained and method for producing a steel workpiece.Type: ApplicationFiled: May 12, 2005Publication date: July 3, 2008Inventors: Jean Beguinot, Dominique Viale
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Publication number: 20080131305Abstract: A high-strength steel sheet has a metal structure consisting of a ferrite phase in which a hard second phase is dispersed and has 3 to 30% of an area ratio of the hard second phase. In the ferrite phase, the area ratio of nanograins of which grain sizes are not more than 1.2 ?m is 15 to 90%, and dS as an average grain size of nanograins of which grain sizes are not more than 1.2 ?m and dL as an average grain size of micrograins of which grain sizes are more than 1.2 ?m satisfy an equation (dL/dS?3).Type: ApplicationFiled: November 30, 2005Publication date: June 5, 2008Inventor: Yoshitaka Okitsu
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Patent number: 7357060Abstract: A vehicle is armored the steps of sequentially making a steel plate with a thickness of 4 mm to 15 mm of by weight 0.2 to 0.4% carbon, 0.3 to 0.8% silicon, 1.0 to 2.5% manganese, max. 0.02% phosphorous, max. 0.02% sulfur, max. 0.05% aluminum, max. 2% copper, 0.1 to 0.5% chromium, max. 2% nickel 0.1 to 1% molybdenum, 0.001 to 0.01% boron, 0.01 to 1% tungsten, max. 0.05% nitrogen, and balance iron and impurities. This plate is heated to above the AC3 temperature and deformed without cooling in a press. While still in the press, the steel plate is cooled and cured. Then the deformed and cured steel plate is taken out of the press and mounted on the motor vehicle without significant further working or shaping.Type: GrantFiled: March 23, 2006Date of Patent: April 15, 2008Assignee: Benteler Automobiltechnik GmbHInventors: Markus Müller, Christian Gnass, Wilfried Rostek, Thomas Tröster, Rainer Lübbers
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Publication number: 20070253857Abstract: Provided is a weld metal for Cr—Mo steels which is suppressed in the formation of ferrite bands and therefore has heightened toughness and tensile strength and at the same time, good SR cracking resistance. The weld metal according to the present invention contains C: 0.02 to 0.06% (mass %, which will equally apply hereinafter), Si: 0.1 to 1.0%, Mn: 0.3 to 1.5%, Cr: 2.0 to 3.25%, Mo: 0.8 to 1.2%, Ti: 0.010 to 0.05%, B: 0.0005% or less (inclusive of 0%), N: 0.002 to 0.0120%, O: 0.03 to 0.07%, and the balance being Fe and inevitable impurities, wherein a ratio of the Ti content [Ti] to the N content [N] satisfies the following range: 2.00<[Ti]/[N]<6.25.Type: ApplicationFiled: February 27, 2007Publication date: November 1, 2007Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Yoshitomi OKAZAKI, Koichi Hosoi
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Patent number: 7264684Abstract: A steel for steel pipes which comprises, on the percent by mass basis, C: 0.2 to 0.7%, Si: 0.01 to 0.8%, Mn: 0.1 to 1.5%, S: 0.005% or less, P: 0.03% or less, Al: 0.0005 to 0.1%, Ti: 0.005 to 0.05%, Ca: 0.0004 to 0.005%, N: 0.007% or less, Cr: 0.1 to 1.5%, Mo: 0.2 to 1.0%, Nb: 0 to 0.1%, Zr: 0 to 0.1%, V: 0 to 0.5% and B: 0 to 0.005%, with the balance being Fe and impurities, in which non-metallic inclusions containing Ca, Al, Ti, N, O, and S are present, and in the said inclusions (Ca %)/(Al %) is 0.55 to 1.72, and (Ca %)/(Ti %) is 0.7 to 19 can be used as a raw material for oil country tubular goods, being used at a greater depth and in severer corrosive circumstances, such as casings and tubings for oil and/or natural gas wells, drilling pipes and drilling collars for excavation, and the like.Type: GrantFiled: July 15, 2005Date of Patent: September 4, 2007Assignee: Sumitomo Metal Industries, Ltd.Inventors: Mitsuhiro Numata, Tomohiko Omura, Yoshihiko Higuchi
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Patent number: 7170073Abstract: A stainless steel slab containing B, wherein a protecting material is joined onto at least two faces across the bloom from each other in a stainless steel bloom containing B of 0.3–2.5 mass %, being integrated into one-piece by forming a weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by following formulas (1)–(4), and a method to produce a steel product by rolling said slab. Further, it is preferable to interpose an insert material between above stainless steel bloom and above protecting material in bonding process. 15?Cr eq?30,??(1) 4?Cr eq?Ni eq?17,??(2) Cr eq=Cr+1.5 Si+Mo?5 B,??(3) Ni eq=Ni+30 (C+N)+0.5 Mn??(4) Herein, each symbol of a chemical element designates the content (mass %) of relevant chemical element contained in steel.Type: GrantFiled: March 11, 2005Date of Patent: January 30, 2007Assignee: Sumitomo Metal Industries, Ltd.Inventors: Kazuhiro Ishida, Kazuhiro Ogawa, Takeo Yazawa, Hideaki Yamamoto, Hideo Morisaki
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Patent number: 7128791Abstract: The present invention provides a martensitic heat resistant alloy having a composition (A) comprising, % by weight: 0.03 to 0.15% of C; 0.01 to 0.9% of Si: 0.01 to 1.5% of Mn; 8.0 to 13.0% of Cr; 0.0005 to 0.015% of Al; no more than 2.0% of Mo; no more than 4.0% of W; 0.05 to 0.5% of V; 0.01 to 0.2% of Nb; 0.1 to 5.0% of Co; 0.008 to 0.03% of B; less than 0.005% of N: and Fe and inevitable impurities as the remainder, wherein (B) the contents (% by weight) of Mo, W, B and N satisfy the following formulae (1) and (2). B?0.772N>0.007??(1) W+1.916Mo?16.99B>2.0??(2) The martensitic heat resistant alloy of the present invention has excellent oxidation resistance, hot workability and ductility and exhibits high creep rupture strength in a range of relatively long rupture time at a high temperature.Type: GrantFiled: January 30, 2002Date of Patent: October 31, 2006Assignees: National Institute for Materials Science, Sumitomo Metal Industries, Ltd., Hitachi, Ltd.Inventors: Toshiaki Horiuchi, Masaaki Igarashi, Fujio Abe
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Patent number: 7048811Abstract: The present invention provides an electric resistance welded steel pipe for a hollow stabilizer excellent in workability, which steel pipe contains, in mass, 0.20 to 0.35% of C, 0.10 to 0.50% of Si, 0.30 to 1.00% of Mn, 0.01 to 0.10% of Al, 0.10 to 1.00% of Cr, 0.005 to 1.00% of Mo, 0.001 to 0.02% of Ti, 0.0005 to 0.0050% of B and 0.0010 to 0.0100% of N, satisfying the expression N/14<Ti/47.9, the balance consisting of Fe and unavoidable impurities and further has an ideal critical diameter (Di) being 1.0 (in) or more, an n-value in the axial direction of the steel pipe being 0.12 or more, a difference in hardness between the electric resistance welded seam portion and the base steel being Hv 30 or less, an average grain size of ferrite being 3 to 40 ?m, an area percentage of the ferritic crystal grains having the aspect ratios of 0.5 to 3.0 being 90% or more in the entire ferrite phase, and having an average grain size of 20 ?m or less in the second phase.Type: GrantFiled: March 4, 2002Date of Patent: May 23, 2006Assignee: Nippon Steel CorporationInventors: Masahiro Ohgami, Tetsuya Magatani, Naoki Takasugi, Osamu Takeda
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Patent number: 6821360Abstract: A heat-resisting steel comprising 0.15-0.30 wt. % C, 0.05-0.3 wt. % Si, 0.01-0.7 wt. % Mn, 1.8-2.5 wt. % Cr, 0.15-0.23 wt. % V, 1.5-2.5 wt. % W, 0.01-0.02 wt. % Ti, 0.01-0.08 wt. % Nb, 0.005-0.03 wt. % N, 0.001-0.015 wt. % B, and Fe and unavoidable impurities as the remainder; a heat-resisting steel comprising 0.15-0.30 wt. % C, 0.05-0.3 wt. % Si, 0.01-0.7 wt. % Mn, 1.8-2.5 wt. % Cr, 0.15-0.23 wt. % V, 1.5-2.5 wt. % W, 0.3-0.8 wt. % Mo, 0.01-0.02 wt. % Ti, 0.01-0.08 wt. % Nb, 0.005-0.03 wt. % N, 0.001-0.015 wt. % B, and Fe and unavoidable impurities as the remainder; and a heat-resisting steel that is obtained by subjecting one of the above heat-resisting steels to a heat treatment comprising the step of oil-cooling the heat-resisting steel to a temperature of 300° C. or lower. These heat-resisting steels are excellent in both high-temperature strength and impact properties.Type: GrantFiled: November 29, 2000Date of Patent: November 23, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Ryuichi Ishii, Yoichi Tsuda, Masayuki Yamada
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Patent number: 6689312Abstract: An alloy and article of manufacture including parts of glass container manufacturing apparatus such as a mold and plunger having a composition which consists of Carbon 0.1 to 0.5%, preferably 0.2 to 0.3% Silicon 0 to 2% preferably 0.5 to 1.5% Manganese 0 to 2% preferably 0.4 to 1.5% Sulphur 0.02 to 0.05% (an incidental element) Phosphorus 0.02 to 0.05% (an incidental element) Nickel 0 to 3% preferably 1.0 to 1.5% Chromium 5 to 35% preferably 15 to 20% Molybdenum 0 to 5% preferably 0.1 to 0.3% Copper 0 to 3% preferably 0.2 to 1% Boron 0.5 to 3.5% preferably 1.8 to 2.2%. The alloy and the articles of manufacture have having excellent high temperature characteristics and substantial hardenability.Type: GrantFiled: November 28, 2001Date of Patent: February 10, 2004Assignee: SG Alternatives, L.L.C.Inventor: Kenneth Donald Lakeland
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Patent number: 6645320Abstract: There is provided a steel sheet which can simultaneously achieves the following objects: high strength is obtained by quenching with reliability; and excellent ductility is ensured, and further which is excellent in corrosion resistance, plating properties, and spot weldability. The steel sheet is so configured as to satisfy the following composition requirements: on a mass basis, C: 0.11 to 0.22%, Mn: 0.1 to less than 0.5%, Cr and/or Mo: a total amount of 0.1 to 0.5%, and B: 0.0005 to 0.005%, where C: the content of C (% by mass), Cr: the content of Cr (% by mass), and Mo: the content of Mo (% by mass), wherein T≧0.19 where T=C+(Cr+Mo)/5.Type: GrantFiled: December 17, 2001Date of Patent: November 11, 2003Assignee: Kobe Steel, Ltd.Inventors: Tatsuya Asai, Tetsuo Soshiroda
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Publication number: 20020114724Abstract: There is provided a steel sheet which can simultaneously achieves the following objects: high strength is obtained by quenching with reliability; and excellent ductility is ensured, and further which is excellent in corrosion resistance, plating properties, and spot weldability. The steel sheet is so configured as to satisfy the following composition requirements: on a mass basis, C: 0.11 to 0.22%, Mn: 0.1 to less than 0.5%, Cr and/or Mo: a total amount of 0.1 to 0.5%, and B: 0.0005 to 0.005%, where C: the content of C (% by mass), Cr: the content of Cr (% by mass), and Mo: the content of Mo (% by mass), wherein T≧0.19 where T=C+(Cr+Mo)/5.Type: ApplicationFiled: December 17, 2001Publication date: August 22, 2002Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Tatsuya Asai, Tetsuo Soshiroda
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Patent number: 6436163Abstract: A porous metal filter possessing enhanced anticorrosive properties is provided including sintered metal particles composed of an alloy composition of iron aluminide having a range in concentration corresponding to Fe3Al to FeAl phases and having a Bubble Point ratio of about 1.6 or less.Type: GrantFiled: December 24, 1998Date of Patent: August 20, 2002Assignee: Pall CorporationInventors: Stephen A. Geibel, Paul C. Koehler, John L. Hurley
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Patent number: 6379611Abstract: A high strength, low alloy, heat resistant steel having excellent weldability has an average crystal grain diameter of at most 110 &mgr;m and consists essentially of, by mass %: C: 0.03-0.15%, Si: at most 1%, Mn: at most 2%, P: at most 0.03%, S: at most 0.03%, Ni: at most 0.5%, Cu: at most 0.5%, Cr: 1.8-2.8%, V: 0.1-0.3%, Nb: 0.01-0.08%, Mo: 0.05-0.35%, W: 1.2-1.8%, Ti: 0.001-0.05%, B: 0-0.02%, Al: at most 0.1%, O: at most 0.1%, N: in an amount satisfying the formula [%N]≦[%Ti]+5[%B]+0.004, and a remainder of unavoidable impurities.Type: GrantFiled: August 18, 2000Date of Patent: April 30, 2002Assignees: Sumitomo Metal Industries, Ltd., Mitsubishi Heavy Industries, Ltd.Inventors: Nobuyoshi Komai, Fujimitsu Masuyama, Tomomitsu Yokoyama, Hiroyuki Hirata, Kaori Kawano, Takao Kan
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Patent number: 6358336Abstract: A heat-resistant steel contains 0.1-3 mass % of Cr and satisfies the following equation: 0.1≦Nb+Mo+V and MX-type complex precipitates formed inside microcrystalline grains contain 30 mass % or more of Mo and 7 mass % or more of Nb. Also provided is a process for producing the alloy steel product involving casting, forging, hot rolling, normalizing, optionally direct quenching, cooling at a predetermined cooling rate, and tempering.Type: GrantFiled: August 30, 2000Date of Patent: March 19, 2002Assignee: Sumitomo Metal Industries, Ltd.Inventor: Kaori Miyata
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Patent number: 6290904Abstract: This invention relates to welding materials for high-Cr steels which exhibit higher toughness and improved creep characteristics. Specifically, this invention relates to a welding material for high-Cr steels which contains, on a weight percentage basis, 0.03 to 0.12% C, up to 0.3% Si, 0.2 to 1.5% Mn, up to 0.02% P, up to 0.01% S, 8 to 13% Cr, 0.5 to 3% Mo, up to 0.75% Ni, 0.15 to 0.3% V, up to 0.01% Nb, 0.05 to 0.3% Ta, 0.1 to 2.5% W, 0.01 to 0.75% Cu, up to 0.03% Al, 0.002 to 0.005% B, up to 0.015% N, and up to 0.01% O, the balance being Fe and incidental impurities. It also relates to such welding materials wherein W is optionally excluded from the aforesaid composition, wherein W is excluded and 0.1 to 3% Co is added, or wherein 0.1 to 3% Co is added to the aforesaid composition.Type: GrantFiled: January 20, 1999Date of Patent: September 18, 2001Assignee: Mitsubishi Heavy Industries, Ltd.Inventors: Takayuki Kawano, Kaneyasu Ishikawa, Nobuhiko Nishimura, Iwami Ishihara, Mitsushige Kumou, Tamao Takatsu, Takashi Inami
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Patent number: 6254697Abstract: The present invention provides a cast steel material for pressure vessels which has improved impact resistance (weldability) and toughness while maintaining its creep rupture strength at a level equal to or higher than the excellent creep rupture strength currently possessed by CrMoV cast steel, as well as a method of making a pressure vessel (or cast steel article) by using this cast steel material which permits a pressure vessel to be made without requiring a material working step such as forging. Specifically, the present invention relates to a cast steel material for pressure vessels which contains C, Si, Mn, Ni, Cr, Mo, V, W, Nb and/or Ta, B, Ti, Al, N, O, P and S in predetermined proportions, the balance being Fe and incidental impurities, provided that the contents of Ti, Al, O and N satisfies the following relationship: N−0.29{Ti−1.5((O−0.89Al)}≦0.Type: GrantFiled: March 16, 2000Date of Patent: July 3, 2001Assignee: Mitsubishi Heavy Industries, Ltd.Inventors: Yasunori Tashiro, Masakatsu Ueno, Akitsugu Fujita, Masatomo Kamada
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Patent number: 6228183Abstract: An ultra-high strength boron-containing steel having a tensile strength of at least about 900 MPa (130 ksi), a toughness as measured by Charpy V-notch impact test at −40° C. (−40° F.Type: GrantFiled: July 28, 1998Date of Patent: May 8, 2001Assignees: ExxonMobil Upstream Research Company, Nippon Steel CorporationInventors: Narasimha-Rao V. Bangaru, Jayoung Koo, Michael J. Luton, Clifford W. Petersen, Hiroshi Tamehiro, Hitoshi Asahi, Takuya Hara, Yoshio Terada
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Patent number: 6224825Abstract: A case hardening steel with a minimum of grain boundary oxidation, suitable for use in the manufacture of mechanical elements with high demands on fatigue resistance and wear resistance, comprising, in % by weight: C 0.12-0.25 Si ≦0.30 Mn 0.30-0.80 Cr 0.30-0.80 Ni 0.20-0.80 Mo 0.10-0.50 Ti 0.020-0.080 Al 0.005-0.10 B 0.001-0.006 remainder Fe+normal impurities.Type: GrantFiled: April 29, 1998Date of Patent: May 1, 2001Assignee: Ovako Steel ABInventor: Rainer R. Leppänen
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Patent number: 6187113Abstract: A steel alloy for pipes, sheet metal or sections for manufacturing bumpers for motor vehicles, wherein the steel alloy contains, in percent by weight, 0.17 to 0.20% carbon, 1.70 to 2.20% manganese, 0.45 to 0.75% chromium, 0.10 to 0.35% molybdenum, 0.03 to 0.05% aluminum, 0.01 to 0.05% titanium, 0.01 to 0.12% vanadium, 0.025 to 0.06% niobium, 0.0001 to 0.10% zirconium, 0.002 to 0.003% Boron, 0.01 to 0.04% nitrogen, up to 0.15% silicon and up to 0.025% phosphorus and up to 0.010% sulfur, wherein the remainder is iron including impurities caused from smelting, and wherein the sum of the alloy components titanium, vanadium and niobium is between 0.16 and 0.25%.Type: GrantFiled: October 6, 1999Date of Patent: February 13, 2001Assignee: Benteler AGInventor: Dieter Töpker
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Patent number: 6136266Abstract: A steel alloy for pipes, sheet metal or sections for manufacturing body reinforcements for motor vehicles, particularly side impact beams or A- and B-column reinforcements, wherein the steel alloy contains in percent by weight 0.1 to 0.17% carbon, 2.0 to 2.8% manganese, 0.4 to 0.8% chromium, 0.1 to 0.35% molybdenum, 0.03 to 0.07% aluminum, 0.002 to 0.003% boron, 0.0001 to 0.005% titanium, 0.08 to 0.012% vanadium, 0.025 to 0.06% niobium, 0.0001 to 0.10 zirconium, 0.01 to 0.05% nitrogen, up to 0.3% silicon, up to 0.025% phosphorus and % 0.010 sulfur, wherein the remainder is iron including impurities caused by smelting, and wherein the sum of the alloy components titanium, vanadium and niobium is between 0.16 and 0.25%.Type: GrantFiled: October 6, 1999Date of Patent: October 24, 2000Assignee: Benteler AGInventor: Dieter Topker
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Patent number: 6126897Abstract: A carburizing steel having the following chemical composition:C: 0.1 to 0.25%,Si: 0.2 to 0.4%,Mn: 0.3 to 0.9%,P: 0.02% or less,S: 0.001 to 0.15%,Cr: 0.5 to 0.9%,Mo: 0.15 to 1%,Al: 0.01 to 0.1%,B: 0.0005 to 0.009%,N: less than 0.006%, andthe balance of Fe and incidental impurities, wherein % is on a weight basis. Also disclosed are a method for the manufacture of the carburizing steel, parts of constant velocity universal joints for drive shafts made of the carburizing steel, as well as a method for the manufacture of such parts. The carburizing steel may further contain Ni: 0.3-4.0%, and one or more elements selected from the group consisting of Ti, Nb, V and Zr: 0.01-0.3% for each. The parts of constant velocity universal joints for drive shafts are manufactured using the carburizing steel of the present invention as a material. When they are carburized and quenched, they exhibit a surface hardness (Hv) of 650-800, core hardness (Hv) of 250-450, and carburized case depth of 0.2-1.2 mm.Type: GrantFiled: August 21, 1998Date of Patent: October 3, 2000Assignees: Sumitomo Metal Industries, Ltd., NTN CorporationInventors: Kenji Aihara, Yasuhide Fujioka, Kazuhiko Yoshida, Tatsuhiro Goto, Akira Wakita
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Patent number: 6095756Abstract: This invention relates to high-Cr precision casting materials containing carbon, silicon, manganese, chromium, nickel, vanadium, niobium, nitrogen, molybdenum, tungsten, cobalt and optionally boron in specific weight proportions, the balance being iron and incidental impurities, as well as turbine blades made by a precision casting process using these materials. Thus, the present invention provides high-Cr precision casting materials which are capable of precision casting and, moreover, have excellent high-temperature strength, as well as inexpensive and highly reliable turbine blades made by using these casting materials and such turbine blades also having lighter weight.Type: GrantFiled: March 3, 1998Date of Patent: August 1, 2000Assignee: Mitsubishi Heavy Industries, Ltd.Inventors: Akitsugu Fujita, Masatomo Kamada, Hiroshi Yokota, Mitsuyoshi Tsuchiya, Yoshinori Tanaka
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Patent number: 5961284Abstract: A steam turbine has main components such as rotor shaft exposed to high temperature and intermediate pressure, which are made of a ferritic steel and the main steam temperature and the re-heat steam temperature are 610.degree. C. to 660.degree. C., and a steam turbine power plant employs the turbine. Further, the rotating blades are made of only a martensitic steel or a combination of the martensitic steel and a Ni base alloy, the turbine rotor is made of a ferritic forged steel having a creep rupture strength at the operating temperature for 100 thousands hours of above 15 kg/mm.sup.2, and the casing is made of a ferritic cast steel having a creep rupture strength at the operating temperature for 100 thousands hours of above 10 kg/mm.sup.2.Type: GrantFiled: August 22, 1996Date of Patent: October 5, 1999Assignee: Hitachi, Ltd.Inventors: Mitsuo Kuriyama, Masao Shiga, Kishio Hidaka, Shigeyoshi Nakamura, Yutaka Fukui, Ryo Hiraga, Nobuo Shimizu, Masao Kawakami
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Patent number: 5945064Abstract: This invention provides a welding material for low chromium (Cr) ferritic heat-resisting steel having high toughness, wherein the chemical composition of welding metal comprises, in weight %, carbon (c) 0.04-0.1%, silicon (Si) 0.1-0.6%, manganese (Mn) 0.1-0.6%, phosphorus (P) 0.0005-0.03%, sulfur (S) 0.0005-0.015%, chromium (Cr) 1.75-2.5%, nickel (Ni) 0.01-0.8%, molybdenum (Mo) 0.05-1.5%, vanadium (V)0.01-0.5%, tungsten (W) 0.05-2%, niobium (Nb) 0.01-0.2%, tantalum (Ta) 0.01-0.5%, aluminum (Al) 0.003-0.05%, boron (B) 0.0001-0.01%, nitrogen (N) 0.003-0.03%, and the remainder comprises iron and inevitable impurities. The welding material satisfies the following formula: C+Cr/20+Mo/15+V/10+W/7+5B.ltoreq.0.8%. According to this invention, the welding material is suitable for welding low Cr ferritic heat-resisting steels having high strength such as those used in steam generators and heat exchangers of boilers, etc.Type: GrantFiled: April 9, 1998Date of Patent: August 31, 1999Assignee: Mitsubishi Heavy Industries, Ltd.Inventors: Nobuyoshi Komai, Takayuki Kawano, Fujimitsu Masuyama, Iwami Ishihara, Tomomitsu Yokoyama
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Patent number: 5928442Abstract: A medium/high carbon low alloy steel which can be cold formed by cold or warm forging and heat treated. The material consists essentially of:______________________________________ Element Weight Percent ______________________________________ Carbon (C) about 0.45-0.65 Manganese (Mn) about 0.35-0.45 Chromium (Cr) about 0.70-0.80 Nickel (Ni) about 0.35-0.50 Molybdenum (Mo) about 0.15-0.30 Titanium (Ti) about 0.01-0.02 Aluminum (Al) about 0.01-0.02 Silicon (Si) about 0.008-0.15 Boron (B) about 0.001-0.003 Iron (Fe) Balance Vanadium (V) Less than about 0.10 Oxygen (O) about 0.002-0.005 Nitrogen (N) about 0.001-0.008 Copper (Cu) Less than about 0.35 Zirconium (Zr) Less than about 0.01 Antimony (Sb) Less than about 0.01 Tin (Sn) Less than about 0.01 Sulfur (S) about 0.001-0.010 Phosphorus (P) about 0.001-0.Type: GrantFiled: January 7, 1998Date of Patent: July 27, 1999Assignee: Snap-On Technologies, Inc.Inventors: Paul M. Machmeier, Anthony M. Matuszewski, Stephen Marsch, William Walsh
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Patent number: 5919415Abstract: The invention relates to a steel and to a process for the manufacture of a steel component formed by cold plastic deformation.Type: GrantFiled: December 31, 1997Date of Patent: July 6, 1999Assignee: AscometalInventor: Claude Pichard
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Patent number: 5855846Abstract: Steel for the manufacture of molds, and especially of molds for injection molding of plastics, whose chemical composition comprises, by weight: 0.17%.ltoreq.C.ltoreq.0.27%, 0%.ltoreq.Si.ltoreq.0.5%, 0%.ltoreq.Mn.ltoreq.2%, 0%.ltoreq.Ni.ltoreq.2%, 0%.ltoreq.Cr.ltoreq.3%, 0%.ltoreq.Mo+W/2.ltoreq.1.5%, 0%.ltoreq.V+Nb/2+Ta/4.ltoreq.0.5%, 0.002%.ltoreq.B.ltoreq.0.015%, 0.005%.ltoreq.Al.ltoreq.0.2%, optionally at least one element taken from sulfur, selenium and tellurium, the sum of the contents of these elements being smaller than or equal to 0.2% optionally at least one element taken from titanium and zirconium, in contents such that the sum of the titanium content and of half the zirconium content is smaller than or equal to 0.3%, optionally at least one element taken from lead and bismuth, the sum of the contents of these elements being smaller than or equal to 0.2%, optionally calcium in a content lower than or equal to 0.Type: GrantFiled: April 29, 1997Date of Patent: January 5, 1999Assignee: Creusot Loire IndustrieInventors: Jean Beguinot, Gilbert Primon, Frederic Chenou
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Patent number: 5855845Abstract: Steel for the manufacture of molds for injection molding of plastics, wherein its chemical composition contains, by weight: 0.35%.ltoreq.C.ltoreq.0.5%, 0%.ltoreq.Si.ltoreq.0.5%, 0.2%.ltoreq.Mn.ltoreq.2.5%, 0%.ltoreq.Ni.ltoreq.4%, 0%.ltoreq.Cr.ltoreq.4%, 0%.ltoreq.Mo+W/2.ltoreq.2%, 0%.ltoreq.Cu.ltoreq.1%, 0%.ltoreq.V+Nb/2+Ta/4.ltoreq.0.5%, 0.005%.ltoreq.Al.ltoreq.0.2%, 0%.ltoreq.B.ltoreq.0.015%, 0%.ltoreq.Ti+Zr/2.ltoreq.0.3%, 0%.ltoreq.S+Se+Te .ltoreq.0.2%, 0%.ltoreq.Pb+Bi.ltoreq.0.2%, 0%.ltoreq.Ca.ltoreq.0.1%, the remainder being iron and impurities resulting from the production, the analysis simultaneously satisfying the following relationships: Cr+3.times.(Mo+W/2)+10.times.(V+Nb/2+Ta/4).gtoreq.1, R=3.8.times.C+10.times.Si+3.3.times.Mn+2.4.times.Ni+1.4.times.(Cr+Mo+W/2). ltoreq.11, Qu=3.8.times.C+1.1.times.Mn+0.7.times.Ni+0.6.times.Cr+1.6.times.(Mo+W/2)+k B.gtoreq.3, with kB=0.5 if B.gtoreq.0.0005% and kB=0 if not, and: R.ltoreq.Max(2.33.times.Qu-1, 0.9.times.Qu+4).Type: GrantFiled: April 29, 1997Date of Patent: January 5, 1999Assignee: Creusot Loire Industrie Societe AnonymeInventors: Jean Beguinot, Gilbert Primon, Frederic Chenou
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Patent number: 5814274Abstract: This invention provides low-Cr ferritic steels and low-Cr ferritic cast steels having excellent high-temperature strength and weldability. These low-Cr ferritic steels and low-Cr ferritic cast steels consist essentially of, on a weight percentage basis, 0.03 to 0.12% C, 0.05 to 0.7% Si, 0.05 to 1% Mn, 0.002 to 0.025% P, 0.001 to 0.015% S, 0.3 to 3% Cr, 0.01 to 1% Ni, 0.05 to 3% Mo, 0.01 to 0.5% V, 0.1 to 3% W, 0.01 to 0.2% Nb, 0.02 to 1.5% Re, 0.003 to 0.05% Al, 0.0001 to 0.01% B, 0.003 to 0.03% N, and the balance being Fe and incidental impurities, and have excellent high-temperature strength and weldability.Type: GrantFiled: February 21, 1997Date of Patent: September 29, 1998Assignee: Mitsubishi Jukogyo Kabushiki KaishaInventors: Nobuyoshi Komai, Fujimitsu Masuyama, Tomomitsu Yokoyama
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Patent number: 5762725Abstract: Steel for the manufacture of forgings having a bainitic structure and the mechanical properties of which are: R.sub.p0.2 .gtoreq.800 MPa, R.sub.m .gtoreq.1000 MPa, K.sub.cu .gtoreq.50 J/cm.sup.2 its chemical composition comprising, by weight: 0.05%.ltoreq.C.ltoreq.0.12%, 0.1%.ltoreq.Si.ltoreq.0.45%, 1.01%.ltoreq.Mn.ltoreq.1.8%, 0.15%.ltoreq.Cr .ltoreq.1.15%, 0.06%.ltoreq.Mo.ltoreq.0.12%, Cu.ltoreq.0.30%, Ni.ltoreq.0.30%, 0.01%.ltoreq.Ti.ltoreq.0.04%, 0.005%.ltoreq.Al.ltoreq.0.04%, 0.006%.ltoreq.N.ltoreq.0.013%, 0.0005% 5 B.ltoreq.0.004%, P.ltoreq.0.025%, 0.02%.ltoreq.S.ltoreq.0.1%, 0%.ltoreq.Pb.ltoreq.0.1%, 0%.ltoreq.Te.ltoreq.0.07%, optionally from 0.0002% to 0.002% of calcium, the balance being iron and impurities resulting from the smelting, the chemical composition furthermore satisfying the relationship: 0.2% .ltoreq.Ni+Mo+Cu.ltoreq.0.7%, the uncombined boron content not being less than 0.0005% above 950.degree. C. Process for the manufacture of a forging.Type: GrantFiled: November 27, 1996Date of Patent: June 9, 1998Assignee: AscometalInventors: Claude Pichard, Jacques Bellus, Gilles Pierson
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Patent number: 5746843Abstract: A low Mn-low Cr ferritic heat resistant steel consisting essentially of, in weight %: 0.02-0.20% C, up to 0.7% Si, less than 0.1% Mn, up to 0.8% Ni, 0.8-3.5% Cr, 0.01-3.0% W, 0.1-0.5% V, 0.01-0.20% Nb, 0.001-0.05% Al, 0.0005-0.05% Mg, 0.0005-0.01% B, less than 0.05% N, up to 0.03% P, up to 0.015% S, 0.001-0.05% Ti and the balance Fe and incidental impurities, wherein the B content is defined so as to satisfy the following formula (14/11)B>N-N(V/51)/{(C/12)+(N/14)}-N(Nb/93)/{(C/12)+(N/14)}-N(Ti/48)/{C/12 )+(N/14)}. The steel can further contain optionally 0.01-1.5% Mo, and/or one or more elements selected from the group consisting of 0.01-0.2% La, 0.01-0.2% Ce, 0.01-0.2% Y, 0.01-0.2% Ca, 0.01-0.2% Ta and 0.01-0.2% Zr. The steel can be used in place of the austenitic steels or high Cr ferritic steels, since it has remarkably improved toughness, workability and weldability, and excellent creep properties at elevated temperatures.Type: GrantFiled: February 10, 1997Date of Patent: May 5, 1998Assignees: Sumitomo Metal Industries, Ltd., Mitsubishi Jukogyo Kabushiki KaishaInventors: Kaori Miyata, Masaaki Igarashi, Fujimitsu Masuyama, Nobuyoshi Komai, Tomomitsu Yokoyama
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Patent number: 5695576Abstract: High-strength high-ductility steel whose chemical composition, by weight, comprises from 0.15% to 0.35% of carbon, from 0% to 3% of silicon, from 0% to 3% of aluminium, from 0.1% to 4.5% of manganese, from 0% to 9% of nickel, from 0% to 6% of chromium, from 0% to 3% of the sum of tungsten divided by two plus molybdenum, from 0% to 0.5% of vanadium, from 0% to 0.5% of niobium, from 0% to 0.5% of zirconium, at most 0.3% of nitrogen and, optionally, from 0.0005% to 0.005% of boron, optionally from 0.005% to 0.1% of titanium, optionally at least one element taken from Ca, Se, Te, Bi and Pb in contents less than 0.2%, the balance being iron and impurities resulting from smelting; the chemical composition furthermore satisfying the relationships: 1%.ltoreq.Si+Al.ltoreq.3% and 4.6.times.(%C)+1.05.times.(%Mn)+0.54.times.(%Ni)+0.66.times.(%Mo+%W/2)+0.5 .times.(%Cr)+K.gtoreq.3.8 where K=0.5 when the steel contains boron, K=0 when the steel does not contain boron.Type: GrantFiled: January 24, 1996Date of Patent: December 9, 1997Assignee: Creusot Loire Industrie (S.A.)Inventor: Jean Beguinot
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Patent number: 5645794Abstract: Low alloy steel for the manufacture of molds for plastics or for rubber, the chemical composition of which comprises, by weight, 0.24% to 0.35% of carbon, 1% to 2.5% of manganese, 0.3% to 2.5% of chromium, 0.1% to 0.8% of molybdenum plus tungsten divided by 2, up to 2.5% of nickel, 0% to 0.3% of vanadium, less than 0.5% of silicon, 0.002% to 0.005% of boron, 0.005% to 0.1% of aluminum, 0% to 0.1% of titanium and less than 0.02% of phosphorus. The chemical composition must furthermore satisfy the relationship:U=409(% C)+19.3[% Cr+% Mo+% W/2+% V]+29.4(% Si)+10(% Mn)+7.2(% Ni)<200and the relationship:R=3.82(% C)+9.79(% Si)+3.34(% Mn)+11.94(% P)+2.39(% Ni)+1.43(% Cr)+1.43(% Mo+% W/2)<11.Type: GrantFiled: October 6, 1995Date of Patent: July 8, 1997Assignee: Creusot Loire InudstrieInventors: Jean Beguinot, Frederic Chenou, Gilbert Primon
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Patent number: 5605559Abstract: Alloy steel powders capable of obtaining high strength in a sintered state and having excellent compacting compressibility and methods of manufacturing a sintered body. The alloy steel powder comprises, by wt %, about 0.5-2% of Cr, not greater than about 0.08% of Mn, about 0.1-0.6% of Mo, about 0.05-0.5% of V, not greater than about 0.015 of S, not greater than about 0.2% of O, and the balance being Fe and incidental impurities. The alloy steel powder is compacted and sintered at a temperature of about 1100.degree.-1300.degree. C. and then cooled at a cooling rate no higher than about 1.degree. C./s in a temperature range of from about 800.degree. C. to 400.degree. C. The alloy steel powder can contain Nb and/or Ti and one or more of Co, W and B. Additionally, Ni powder and/or Cu powder may be adhered and dispersed onto the surface of the alloy steel powder.Type: GrantFiled: February 22, 1995Date of Patent: February 25, 1997Assignee: Kawasaki Steel CorporationInventors: Shigeru Unami, Satoshi Uenosono
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Patent number: 5407635Abstract: A low-Cr ferritic steel with improved toughness as well as creep strength is disclosed, which consists essentially of, by weight %:C: 0.03-0.12%, Si: 0.70% or less, Mn: 0.10-1.50%,Ni: 2.0% or less, Cr: 1.50-3.50%, W: 1.0-3.0%,V: 0.10-0.35%, Nb: 0.01-0.10%,B: 0.00010-0.020%, N: 0.005% or less,Al: 0.005% or less,Ti: not less than 0.001% but less than 0.05%,Cu: 0.10-2.50%,at least one of La, Ce, Y, Ca, Zr, Ta each in an amount of 0-0.20%, and Mg in an amount of 0-0.05%,Mo in an amount of 0-0.40%, anda balance of Fe and incidental impurities including P: not more than 0.030% and S: not more than 0.015%.Type: GrantFiled: March 12, 1993Date of Patent: April 18, 1995Assignees: Sumitomo Metal Industries, Ltd., Mitsubishi Jukogyo Kabushiki KaishaInventors: Atsuro Iseda, Yoshiatsu Sawaragi, Fujimitsu Masuyama, Tomomitsu Yokoyama
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Patent number: 5211909Abstract: A low-alloy steel consists essentially, on a weight basis, of: C: 0.03-0.12%, Si: at most 0.7%, Mn: 0.1-1.5%, Ni: at most 0.8%, P: at most 0.03%, S: at most 0.015%, Cr: 1.5-3.5%, W: 1-3%, V: 0.1-0.35%, Nb: 0.01-0.1%, B: 0.0001-0.02%, N: less than 0.005%, Al: less than 0.005%, Ti: 0.001-0.1%, optionally one or more elements selected from the group consisting of: La, Ce, Y, Ca, Zr, and Ta: 0.01-0.2%, Mg: 0.0005-0.05%, and Mo: 0.01-0.4%, and a balance of Fe and incidental impurities, wherein the Ti and Ni contents satisfy the following inequality:0.080.gtoreq.Ti(%)-(48/14).times.N(%).gtoreq.0.003.The steel has improved creep strength at high temperatures and improved toughness. It can be substituted for expensive austenitic stainless steels or high-Cr ferritic steels.Type: GrantFiled: February 20, 1992Date of Patent: May 18, 1993Assignees: Sumitomo Metal Industries, Ltd., Mitsubishi Jukogyo Kabushiki KaishaInventors: Atsuro Iseda, Yoshiatsu Sawaragi, Fujimitsu Masuyama, Tomomitsu Yokoyama
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Patent number: 5186768Abstract: A flat spring hose clamp having an improved resistance to brittle fracture and a method for manufacturing the same are disclosed, the hose clamp being made of a steel having a steel composition consisting essentially of, by weight %:C:0.30-0.70%,Si: 0.70% or less,Mn: 0.05-1.00%,P: 0.030% or less,S: 0.020% or less,Cr: 0.50-2.00%,Mo: 0.10-0.50%,Nb: 0.005-0.100%,sol. Al: 0.10% or less,N: more than 0.0020%, but not more than 0.015%,Ti: 0-0.10% and/or B: 0-0.0020%,and a balance of Fe and incidental impurities, and the steel possessing a uniform bainite structure.Type: GrantFiled: June 13, 1991Date of Patent: February 16, 1993Assignees: Sumitomo Metal Industries, Ltd., Togo Seisakusyo CorporationInventors: Masai Nomoto, Koichi Sakurai, Takashi Suzuki, Kiyoshi Fukui, Atsuki Okamoto
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Patent number: 4957702Abstract: Air-hardenable steels of duplex bainite/martensite microstructure consisting essentially of 0.10 to 0.7% C, 0.1 to 2% Si, 2.1 to 3.5% Mn, 0.0005 to 0.005% B, up to 3.5% Cr and preferably containing Cr in amount of at least 0.1%, balance Fe except for incidental impurities. Optional elements are up to 1.5% W, 1.0% Mo, 0.15% V, 0.2% S, 0.1% Ca, 0.1% Pb, 0.1% Ti and 0.2% total rare earths. At least 1.0% Cr is especially preferred and if below such amount, total Mn and Si is at least 3% and in such case, if C is under 0.47%, at least 0.6% Si is present. The steels are hardenable to R.sub.c 20 to R.sub.c 58 and have a hardenable diameter in the range between 35 mm and 80 to 100 mm by air-cooling only, together with good strength, toughness and fatigue- and wear-resistance.Type: GrantFiled: December 12, 1988Date of Patent: September 18, 1990Assignee: Qinghua UniversityInventors: Hongsheng Fang, Yankang Zheng, Xiuyun Chen, Donghao Chen, Rufa Zhao
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Patent number: 4902473Abstract: A brake disc material which does not crack under a great braking action, such as in a large-sized truck, consisting of 0.03 percent to 1 percent of carbon, 1.2 percent to 20 percent of chromium, and 0.1 percent to 1 percent of molybdenum, the balance being essentially iron.Type: GrantFiled: November 16, 1987Date of Patent: February 20, 1990Assignee: Nippon Steel CorporationInventors: Hiroto Arata, Kenji Shiga, Daihachiro Sakurai, Kazuo Fujisawa, Isao Souma, Yusiyo Watanabe, Akira Tanaka
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Patent number: 4844755Abstract: A high-strength, heat-resisting ferritic steel pipe or tube for boiler use containing 0.03 to 0.15% C, 0.1 to 1.5% Mn, 8 to 13% Cr, 1.8 to 3.0% W, 0.05 to 0.30% V, 0.02 to 0.12% Nb, 0.02 to 0.05% N, 0.02 to 0.4% Mo, and up to 0.25% Si. This pipe or tube has an improved high-temperature creep rupture strength and an excellent weldability and toughness.Type: GrantFiled: August 29, 1988Date of Patent: July 4, 1989Assignee: Nippon Steel CorporationInventors: Katukuni Hashimoto, Yasuo Otoguro, Toshio Fujita
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Patent number: 4834814Abstract: Metallic glasses having high permeability, low magnetostriction, low coercivity, low ac core loss, low exciting power and high thermal stability are disclosed. The metallic glasses consist essentially of a composition defined by the formula Fe.sub.a M.sub.b B.sub.c Si.sub.d C.sub.e in which "a"-"e" are in atom percent, the sum ("a"+"b"+"c"+"d"+"e") equals 100, M is at least one element selected from the group consisting of Mo, Cr, Ti, Zr, Hf, Nb, Ta, V and W, "a" ranges from about 66 to 81.5, "b" ranges from about 0.5 to 6, "c" ranges from about 10 to 26, "d" ranges from about 1 to 12, "e" ranges from about 0 to 2 and the sum ("c"+"d"+"e") ranges from about 18 to 28, and have been annealed at a temperature, T.sub.a, for a time, t.sub.a, sufficient to induce precipitation of discrete particles therein. Such metallic glasses are suitable for use in tape recorder heads, relay cores, transformers and the like.Type: GrantFiled: March 7, 1988Date of Patent: May 30, 1989Assignee: Allied-Signal Inc.Inventors: Ryusuke Hasegawa, Gordon E. Fish
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Patent number: 4820486Abstract: The present invention relates to low alloy steel and specifically to nickel-chrome-molybdenum steel.A low alloy steel having excellent stress corrosion cracking resistance containing C:.ltoreq.0.40%, Si:.ltoreq.0.15%, Mn:.ltoreq.0.20%, P:.ltoreq.0.010%, S:.ltoreq.0.030%, Ni: 0.50 to 4.00%, Cr: 0.50 to 2.50%, Mo: 0.25 to 4.00% and V:.ltoreq.0.30%, said Si, Mn and P being fulfilled with relationship of Si+Mn+20P.ltoreq.0.30%, the remainder comprising Fe and unavoidable impurities, the prior austenite crystal grain size being in excess of 4 of ASTM crystal grain size number.Type: GrantFiled: March 31, 1986Date of Patent: April 11, 1989Assignee: Kabushiki Kaisha Kobe Seiko ShoInventors: Kazutoshi Shimogori, Kazuo Fujiwara, Kiyoshi Sugie, Kikuo Morita, Takenori Nakayama, Mutsuhiro Miyakawa, Yasushi Torii
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Patent number: 4772451Abstract: A low-alloy steel suitable for use in caster shells for continuous aluminum casting operations. It has a lower carbon and chromium content than prior art steels, and exhibits high yield strength at elevated temperatures, excellent toughness over the entire temperature range of aluminum casting, and decreased heat checking.Type: GrantFiled: September 30, 1987Date of Patent: September 20, 1988Assignee: Earle M. Jorgensen Co.Inventors: Rockne J. Andreini, Sveltana Yaguchi
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Patent number: 4729872Abstract: Isotropic tool steel consisting essentially of necessary elements as tool steel, less than 0.005 weight % of S and less than 30 ppm of O, the balance being substantially Fe. The necessary elements are, by weight, 0.10-0.70% of C, 2.00% or less of Si, 2.00% or less of Mn, 7.00% or less of Cr, 0.20-12.00% of W and/or Mo alone or in combination (1/2W+Mo), 3.00% or less of V. They may further include at least one of 4.00% or less of Ni, 6.50% or less of Co and 0.20% or less of N. The isotropic tool steel has cleanliness with respect to non-metallic inclusions defined by JIS G 0555 of dA60.times.400.ltoreq.0.010% and d(B+C)60.times.400.ltoreq.0.020%, and a ratio of transverse direction toughness to longitudinal direction toughness of more than 0.70. Since it is highly resistant to the generation and propagation of cracks and fracture, dies for hot working made therefrom can enjoy a long life.Type: GrantFiled: September 10, 1986Date of Patent: March 8, 1988Assignee: Hitachi Metals, Ltd.Inventors: Tamiya Kishida, Mitsuru Suzuki, Toshio Okuno, Atsusuke Nakao