With Working Patents (Class 148/598)
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Patent number: 6261388Abstract: A cold forging steel excellent in grain coarsening prevention and delayed fracture resistance and method of producing the same are provided that enable omission of a step of annealing or spheroidization annealing before cold forging and improvement of delayed fracture resistance of a high-strength component used with a heat-treated surface. The cold forging steel is a steel of a specified composition having dispersed in the matrix thereof particles of not greater than 0.2 &mgr;m diameter of one or more of TiC, Ti(CN), NbC, Nb(CN) and (Nb, Ti)(CN) in a total number of not less than 20/100 &mgr;m2. The method of producing a cold forging steel includes the steps of heating this steel to not lower than 1050° C., hot-rolling the steel into steel wire or steel bar, and slowly cooling the steel at a cooling rate of not greater than 2 C./s during cooling to a temperature not higher than 600° C. to obtain a steel having dispersed in the matrix thereof particles of not greater than 0.Type: GrantFiled: May 18, 1999Date of Patent: July 17, 2001Assignee: Nippon Steel CorporationInventors: Manabu Kubota, Tatsuro Ochi, Hideo Kanisawa, Atsushi Murakami, Masao Ishida
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Patent number: 6238498Abstract: A method for fabricating a homogeneous wire of inter-metallic alloy comprising the steps of providing a base-metal wire bundle comprising a metal, an alloy or a combination thereof; working the wire bundle through at least one die to obtain a desired dimension and to form a precursor wire; and, controllably heating the precursor wire such that a portion of the wire will become liquid while simultaneously maintaining its desired shape, whereby substantial homogenization of the wire occurs in the liquid state and additional homogenization occurs in the solid state resulting in a homogenous alloy product.Type: GrantFiled: March 16, 1999Date of Patent: May 29, 2001Assignee: U T BattelleInventors: Evan Keith Ohriner, Craig Alan Blue
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Patent number: 6228188Abstract: A process of patenting at least one steel wire (10) with a diameter less than 2.8 mm. The cooling is alternatingly done by film boiling in water (14, 16) during one or more water cooling periods and in air during one or more air cooling periods. A water cooling period immediately follows an air cooling period and vice versa. The number of the water cooling periods, the number of the air cooling periods, the length of each water cooling period are so chosen so as to avoid the formation of martensite or bainite.Type: GrantFiled: July 22, 1994Date of Patent: May 8, 2001Assignee: N.V. Bekaert S.A.Inventors: Dirk Meersschaut, Godfried Vanneste
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Patent number: 6217678Abstract: The present invention provides a steel wire rod or bar which exhibits good cold deformability even though it does not undergo spheroidizing annealing after hot rolling. The steel wire rod or bar with good cold deformability is characterized in that its ferrite structure contains no less than 25 nitride and carbide particles in a mixed state or composite state per 25 &mgr;m on average in a sectional area three-fourths of the diameter within the circumference of the rod or bar. Such nitride and carbide precipitates contribute to the reduction of flow stress at temperatures raised by heat generation at the time of cold deforming.Type: GrantFiled: April 21, 1999Date of Patent: April 17, 2001Assignee: Kabushiki Kaisha Kobe Seiko ShoInventors: Kan Momozaki, Hideo Hata, Toyofumi Hasegawa
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Patent number: 6206984Abstract: A non-heat treated wire or bar steel for springs which is characterized by having in its as-rolled state a tensile strength of 120-150 kgf/mm2 and a bending breakage rate no higher than 15% when tested according to JIS Z-2248 under the condition of r/d=2.8 where r (mm) denotes the inside radius of the bending curvature and d (mm) denotes the diameter of the as-rolled stock.Type: GrantFiled: May 3, 1999Date of Patent: March 27, 2001Assignee: Kabushiki Kaisha Kobe Seiko ShoInventors: Atsushi Inada, Nao Yoshihara, Nobuhiko Ibaraki
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Patent number: 6106637Abstract: A ready-to-use metal wire comprising microalloyed steel with a structure almost entirely made up of a cold-hammered annealed martensite is disclosed. The wire diameter is of at least 0.10 mm and at most 0.50 mm, and the ultimate tensile strength of the wire is of at least 2800 MPa. The method of producing said wire comprises deforming a wire rod, performing a hardening heat treatment on the deformed wire and heating it to an annealing temperature to cause the formation of a structure almost entirely made up of annealed martensite. The wire is then cooled and deformed. Assemblies comprising at least one such wire, and wire or assemblies used in particular for reinforcing pneumatic tires, are also disclosed.Type: GrantFiled: July 14, 1998Date of Patent: August 22, 2000Assignee: Michelin & CieInventors: Jean-Claude Arnaud, Eric Depraetere, Marc Francois, Raoul Serre
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Patent number: 6048416Abstract: Steel, steel wire, and a process for forming a drawn wire, especially tire-reinforcing wire of diameter smaller than 0.4 mm, by drawing a steel of the following composition by weight: 0.005%.ltoreq.carbon.ltoreq.0.050%; 0.005%.ltoreq.nitrogen.ltoreq.0.050%; 0.1%.ltoreq.silicon.ltoreq.2.0%; 0.1%.ltoreq.manganese.ltoreq.5%; 5%.ltoreq.nickel.ltoreq.12%; 10%.ltoreq.chromium.ltoreq.20%; 0.01%.ltoreq.copper.ltoreq.4%; 0.01%.ltoreq.molybdenum.ltoreq.3%,the base wire being subjected to:drawing to a cumulative deformation ratio .epsilon. of larger than 2 and smaller than 4,an intermediate annealing treatment at above 700.degree. C.final drawing to a cumulative deformation ratio .epsilon. of smaller than 4.5 and larger than 3.Type: GrantFiled: April 29, 1999Date of Patent: April 11, 2000Assignees: Ugine-Savoie Imphy, Sprint Metal - Societe de Production Internationale de TrefilesInventors: Jean-Michel Hauser, Joel Marandel
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Patent number: 5958158Abstract: The invention relates to a process for producing hot-worked elongated products, such as bars or tubes, from high-alloy or hypereutectoid steel in which a feedstock is heated to a deformation temperature and undergoes at least one deformation step. Following the at least one deformation step, the deformed feedstock is either cooled or heated at a specific temperature to achieve a uniform temperature distribution throughout the length and thickness of the deformed feedstock. Next the deformed feedstock is reheated to a temperature below the deformation temperature. The reheated feedstock is continuously rolled in a multi-stand reducing mill to its final size and then cooled by ambient air.Type: GrantFiled: November 10, 1997Date of Patent: September 28, 1999Assignee: Mannesmann AktiengesellschaftInventors: Heinz Kron, Karlheinz Kutzenberger, Gunther Manig, Gustav Zouhar
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Patent number: 5922149Abstract: A method for making steel wires, wherein an elongate shaped wire is produced by rolling or drawing steel consisting of 0.05-0.5% C, 0.4-1.5% Mn, 0-2.5% Cr, 0.1-0.6% Si, 0-1% Mo, no more than 0.25% Ni, and no more than 0.02% S and P, and a first heat treatment is performed on the shaped wire, including at least one step of quenching under predetermined conditions to achieve an HRC hardness of at least 32, a predominately martensitic and bainitic steel structure and a small amount of ferrite. A shaped wire and a flexible tube for conveying an H.sub.2 S-containing effluent are disclosed.Type: GrantFiled: November 4, 1997Date of Patent: July 13, 1999Assignees: Institut Francais du Petrole, CoflexipInventors: Jose Mallen Herrero, Fran.cedilla.ois Ropital, Andre Sugier
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Patent number: 5885370Abstract: Magnetic heat treatment of steel, characterized by transforming steel containing about 0.01 to 2.0 mass % of carbon in a magnetic field having a gradient of about 0.1 T/cm or more and about 10 T/cm or less (absolute value) at the Curie point or lower, to effectively refine the microstructure by subjecting the steel to heat treatment in a strong magnetic field having a gradient, followed by advantageously improving the mechanical properties of the steel.Type: GrantFiled: April 13, 1998Date of Patent: March 23, 1999Assignee: Kawasaki Steel CorporationInventors: Michio Shimotomai, Akihiro Matsuzaki, Yasunori Yonehana
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Patent number: 5762724Abstract: A high strength steel strand for PC of a wire material having a pearlite structure and containing 0.80 to 1.30% of C, 0.60 to 2.50% of Si and 0.30 to 1.50% of Mn, remainder being Fe and unavoidable impurities, wherein a cementite portion of the wire material comprises a mixed structure of fibrous cementite and granular cementite, the volumetric proportion of the granular cementite to the total cementite is 10 to 40%, the particle diameter of the granular cementite is 40 to 300.ANG., and the strand has a tensile strength of 235 kgf/mm.sup.2 or higher and an elongation of 3.5% or greater.Type: GrantFiled: August 22, 1996Date of Patent: June 9, 1998Assignee: Shinko Kosen Kogyo Kabushiki KaishaInventors: Yukio Yamaoka, Masao Yamada, Masaru Kodama, Toshiki Suwa, Nobuhiko Ibaraki, Masato Kaiso
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Patent number: 5667604Abstract: A process for the manufacture of a scraper or brush wire with increased wear resistance, in which a rolled steel wire with a carbon content of approximately 0.6 to 0.7% and a diameter of approximately 6 mm and smaller is brought to a final diameter by at least one drawing process, where the wire is patented prior to the drawing or in between successive drawing processes, and after the drawing is heat-treated, and where a steel wire alloyed with a chromium content of 0.3% or smaller is used.Type: GrantFiled: March 12, 1996Date of Patent: September 16, 1997Assignee: RIWO-Drahtwerk GmbHInventor: Jorg Karch
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Patent number: 5665182Abstract: This invention provides high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high-carbon steel wire rod or wire is characterized in that it contains, in weight percent, C: 0.90-1.10%, Si: not more than 0.40% and Mn: not more than 0.50%, is limited to P: not more than 0.02%, S: not more than 0.01% and Al: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-0.30% as an alloying component.Type: GrantFiled: October 31, 1995Date of Patent: September 9, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5662747Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C : 0.90-1.10%, Si : not more than 0.40% and Mn : not more than 0.50%, if required contains Cr : 0.10-0.30%., and is limited to Al : not more than 0.003%, P : not more than 0.02% and S : not more than 0.01%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC : carbon content (wt %),TS : tensile strength (kgf/mm.sup.2), andRA : reduction of area (%).Type: GrantFiled: October 5, 1995Date of Patent: September 2, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5658399Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C: 0.80-0.90%, Si: 0.10-1.50% and Mn: 0.10-1.00%, if required contains Cr: 0.10-1.00%, and is limited to P: not more than 0.02%, S: not more than 0.01% and A1: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC: carbon content (wt%),TS: tensile strength (kgf/mm.sup.2), andRA: reduction of area (%).Type: GrantFiled: October 5, 1995Date of Patent: August 19, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5658402Abstract: This invention relates to high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high carbon steel wire rod or wire excellent in is characterized in that it contains, in weight percent, C: 0.70-1.20%, Si: 0.15-1.00% and Mn: 0.30-0.90%, further contains as alloying components one or both of Al: 0.006-0.100 and Ti: 0.01-0.35%, is limited to P: not more than 0.02% and S: not more than 0.01%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-0.50% as an alloying component.Type: GrantFiled: October 31, 1995Date of Patent: August 19, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5650027Abstract: This invention relates to high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high carbon steel wire rod or wire excellent in is characterized in that it contains, in weight percent, C: 0.80-0.90%, Si: 0.10-1.50% and Mn: 0.10-1.00, is limited to P: not more than 0.02%, S: not more than 0.01% and Al: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-1.00% as an alloying component.The high-carbon steel wire rod or wire according to this invention can be drawn to an appreciably higher reduction of area than prior art products and also has improved delamination resistance property.Type: GrantFiled: October 31, 1995Date of Patent: July 22, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5647918Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C: 0.70-1.20%, Mn: 0.30-0.90% and Si: 0.15-1.00%, further contains as alloying components one or both of Al: 0.006-0.100% and Ti: 0.01-0.35%, if required contains Cr: 0.10-0.50%, and is limited to P: not more than 0.02% and S: not more than 0.01%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC: carbon content (wt %),TS: tensile strength (kgf/mm.sup.2), andRA: reduction of area (%).Type: GrantFiled: October 5, 1995Date of Patent: July 15, 1997Assignee: Nippon Steel CorporationInventors: Akifumi Kawana, Hiroshi Oba, Ikuo Ochiai, Seiki Nishida
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Patent number: 5578149Abstract: The present invention is directed to an expandable stent for use in blood vessels. The length of the stent after expansion is substantially the same as the stent length before expansion. The stent is annealed at high temperatures to permit stent deformation at relatively low pressures to conform to the blood vessel shape and diameter.Type: GrantFiled: May 31, 1995Date of Patent: November 26, 1996Assignee: Global Therapeutics, Inc.Inventors: Ivan De Scheerder, Joseph B. Horn
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Patent number: 5542995Abstract: A method of making flat steel strapping or strip from rods, bars or slit steel includes the steps of heating a piece of steel to an elevated temperature greater than the upper critical temperature, hot rolling the steel and quenching the rolled steel from a temperature that is above the upper critical temperature or in the range of the lower critical temperature to the upper critical temperature.Type: GrantFiled: December 16, 1993Date of Patent: August 6, 1996Inventor: Robert Reilly
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Patent number: 5458699Abstract: A steel wire for making a high strength steel wire product which contains 0.6-1.1% C, 0.2-0.6% Si, 0.3-0.8% Mn, and impurities of max 0.010% P, max 0.010% S, max 0.003% O(oxygen), and max 0.002% N, and has a structure in which the maximum pearlite block size is 4.0 .mu.m, the maximum separation distance in pearlite lamellars is 0.1 .mu.m, and the maximum content of free ferrite is 1% by volume.The steel wire can be manufactured in the process as follows;1 heating a steel wire rod having above-mentioned chemical composition to the austenite range above Ac.sub.3 point or A.sub.cm point,2 initiating plastic deformation to not less than 20% total reduction in cross-sectional area in the temperature range 850.degree. C. -750.degree. C.,3 finishing plastic deformation in the range below Ae.sub.1 point and above 650.degree. C., and4 continuously cooling to a range lower than 650.degree. C. and higher than 550.degree. C., and thus transforming into pearlite phase.Type: GrantFiled: May 10, 1994Date of Patent: October 17, 1995Assignee: Sumitomo Metal Industries, Ltd.Inventors: Takashi Tsukamoto, Terutaka Tsumura, Masatake Tomita, Michitaka Fujita, Motoo Asakawa
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Patent number: 5342700Abstract: A metal wire having the following features:(a) it is formed, at least in part, by a steel having a carbon content of at least 0.1% and at most 0.6% and a boron content of less than 8 ppm;(b) the steel of the wire has a strain-hardened lower bainite type structure (7);(c) the diameter of the wire varies from 0.10 to 0.40 mm;(d) the resistance to rupture of the wire is at least equal to 2800 MPa;(e) the elongation upon rupture of the wire is at least equal to 0.4%.The method according to the invention for producing this wire consists in strain hardening a machine wire having 28% to 90% proeutectoid ferrite and 72% to 10% perlite, thereupon carrying out a heat treatment to obtain a structure of lower bainite type, then effecting a strain hardening on the wire, the temperature of the wire upon the strain hardening being less than 0.3 T.sub.F, T.sub.F being the melting point of the steel expressed in Kelvin.Type: GrantFiled: June 17, 1992Date of Patent: August 30, 1994Assignee: Compagnie Generale des Establissements Michelin-Michelin & CieInventors: Jean-Claude Arnaud, Bernard P. Prudence
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Patent number: 5284534Abstract: A thermomechanical method for improving the fatigue characteristics of a metallic material (for example carbon steel and low alloy steel) takes advantage of the materials' plastic flow characteristics to improve external and internal surface conditions. The material is heated to a temperature in the range of about 0.3 to 0.45 its homologous temperature, e.g., from about 200 degrees C to about the Young's Modulus Transition Temperature of said material. While the temperature of the material is in this range, force is applied to the material to produce in at least the region of said material to be treated a tensile stress level greater than the yield point of said material at the temperature, and thereby to produce limited plastic elongation in the region. The material is then cooled under stress, the stress being maintained above the instantaneous yield point of the material during at least part of the cooling process. As a result of this process, the shape of existing stress raisers (e.g.Type: GrantFiled: November 8, 1991Date of Patent: February 8, 1994Inventor: Carlos A. T. Mendes
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Patent number: 5261974Abstract: A high-strength extra fine metal wire of a diameter of 0.01-0.50 mm containing 0.60 wt %-1.20 wt % carbon, consisting of a metal structure in the form of bundle of said carbides and presenting a shape about rectangular or circular in which the ratio of the length in the longitudinal direction to the length in the direction of width in the cross section is no more than 2.5 and the mean sectional area is no more than 150.times.10.sup.-4 .mu.m.sup.2, and improving strength and tenacity by having a tensile strength of 300 kgf/mm.sup.2 or over.Type: GrantFiled: July 8, 1992Date of Patent: November 16, 1993Assignee: Tokusen Kogyo Company LimitedInventors: Kenji Hyodo, Ichiro Nagao
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Patent number: 5252153Abstract: A steel comprising 0.1 to 1.5% of C and 0.25 to 2.0% of Mn is heated to 900.degree. to 1250.degree. C., and the heated steel is hot-rolled at a temperature in the range of from Ar.sub.3 to (Ar.sub.3 +200).degree. C. or Arcm to (Arcm+200).degree. C. with a total reduction of area of 30% or more. The hot-rolled material is cooled to complete a ferrite/pearlite transformation or a pro-eutectoid cementite/pearlite transformation. The transformed material is subjected to finish hot rolling at a temperature in the range of from (Ac.sub.1 -400) to Ac.sub.1 .degree. C. with a total reduction ratio of 10 to 70%. If necessary, the material after the finish hot rolling is cooled to 300.degree. C. at an average cooling rate of 1.degree. C./sec or less. A spheroidization annealing of the steel bar wire rod produced according to the process of the present invention enables a good spheroidized texture to be formed.Type: GrantFiled: June 10, 1992Date of Patent: October 12, 1993Assignee: Nippon Steel CorporationInventors: Tatsuro Ochi, Yoshiro Koyasu, Yukio Noguchi
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Patent number: 5248353Abstract: The present invention is concerned with a method of producing steel wires each having a very small diameter of 0.4 mm or less and a tensile strength of 360 kgf/mm.sup.2 or more wherein a steel material having a composition comprisingC: 0.90 to 1.10% by weight, Si: 0.4% or less by weight, Mn: 0.5% or less by weight, Cr: 0:10 to 0.30% by weight and a balance of iron an unavoidable impurities is subjected to diffusion treatment as desired, thereafter, the steel material is subjected to hot rolling, the hot-rolled steel wire is subjected to drawing, subsequently, the resultant steel rod having a smaller diameter is subjected to a final patenting treatment to give said rod a strength of 140 to 160 kgf/mm.sup.2, and thereafter, it is subjected to drawing with a true strain of 3.50 or more using a die having a die approach angle of 8 to 12 degrees.Type: GrantFiled: February 25, 1992Date of Patent: September 28, 1993Assignee: Nippon Steel CorporationInventors: Seiki Nishida, Ikuo Ochiai, Hiroshi Oba, Osami Serkiawa
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Patent number: 5236520Abstract: Sway bars made of high strength steel having grains with a preferred orientation, and methods of making such sway bars from blanks of high strength steel typically having a yield strength of at least about 90,000 psi and a tensile strength of at least about 120,000 psi.Type: GrantFiled: March 9, 1992Date of Patent: August 17, 1993Assignee: Consolidated Metal Products, Inc.Inventor: Hugh M. Gallagher, Jr.
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Patent number: 5213637Abstract: A method of producing steel wires intended for the manufacture of flexible conduits, steel wires obtained by this method, and flexible conduits reinforced by such wires is characterized by the fact that, for a given strain-hardening rate of the initial wire, a heat treatment is carried out under conditions of time and temperature such that the steel wire obtained after treatment has a mechanical rupture strength (Rm) greater than 850 MPa and a structure containing little free ferrite.Type: GrantFiled: December 19, 1991Date of Patent: May 25, 1993Assignees: Coflexip, Institut Francais du PetroleInventors: Jose M. Mallen Herrero, Andre Sugier
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Patent number: 5213632Abstract: A process is disclosed for obtaining a high-strength, strain-hardened steel wire by drawing a rod wire, optionally with intermediate thermal treatment. The rod wire is produced from a steel that is devoid of proeutectoid cementoid, and which comprises 0.45-0.75% C, less than 0.010% each of S and P, and conventional proportions of Mn, Si, Ca, Mo, and Al. The wire-drawing operation is carried out in two distinct phases, separated from each other by a single brassing-patenting treatment. In the final wire-drawing step the level of cross-sectional reduction is greater than 97 per cent. The level of cross-sectional reduction is also exceptionally high during the first wire-drawing phase as a result of elimination of conventional intermediate patenting.Type: GrantFiled: February 5, 1992Date of Patent: May 25, 1993Assignee: Sodetal SarlInventors: Luc Peeters, Jean B. Pelletier
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Patent number: 5156692Abstract: A wire of a high-carbon steel having a carbon content of 0.7%-0.9% by weight is heat-treated so as to form supercooled austenitic phases, then subjected to plastic deformation with a reduction rate of at least 20% in the temperature range of below the Ae.sub.1 point and above 500.degree. C., and transformed into pearlite without heating to the austenitic range.The resulting pearlite has a pearlite block size of not greater than 5.0 .mu.m. Steel filaments which have a tensile strength of at least 400 kgf/mm.sup.2 and a reduction of area of at least 40% and which are suitable for use as tire cords in automobile tires can be obtained by wire drawing of the steel wire.Type: GrantFiled: October 9, 1991Date of Patent: October 20, 1992Assignee: Sumitomo Metal Industries, Ltd.Inventor: Takashi Tsukamoto
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Patent number: 5112411Abstract: A mining and construction bit body is composed of a Mn-B steel alloy composition. The alloy content of the composition in percents by weight includes: carbon, 0.33-0.38; manganese, 1.10-1.35; boron, 0.0005 minimum; silicon 0.15-0.30; sulfur, 0.045 maximum; and phosphorus, 0.035 maximum. The composition has a minimum hardenability of 47 Rockwell C at the Jominy 6/16 position and a maximum as-rolled hardness of 22 Rockwell C such that without anneal the composition meets hardenability and machinability requirements that make it useful for fabricating mining and construction bit bodies of all sizes.Type: GrantFiled: November 29, 1990Date of Patent: May 12, 1992Assignee: Kennametal Inc.Inventor: Mark S. Greenfield