With Additional Nonworking Heating Step Patents (Class 148/653)
  • Patent number: 6290787
    Abstract: The subject for the invention is a process for manufacturing strip. The process includes casting directly from liquid metal a steel strip 1.5 to 10 mm in thickness, subjecting the cast steel strip, in the austenitic phase, to a first hot rolling operation in one or more steps at a temperature of between 950° C. and the Ar3 temperature of said strip with an overall reduction ratio of at least 10%, then subjecting the hot rolled strip, in the ferritic phase, to a second hot rolling operation in one or more steps at a temperature below 850° C., with an overall reduction ratio of at least 50% in the presence of a lubricant, so as to obtain a hot-rolled sheet with a thickness of less than or equal to 2 mm, and recrystallizing the hot rolled sheet at a temperature between 700 and 800° C. The composition of the steel strip comprises (in weight %): carbon less than 0.1%, manganese from 0.03 to 2%, silicon from 0 to 0.5%, phosphorus from 0 to 0.1%, boron from 0 to 0.002%, titanium from 0 to 0.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: September 18, 2001
    Assignee: Sollac
    Inventors: Michel Babbit, Michel Faral, Catherine Juckum, Hélène Regle
  • Patent number: 6270594
    Abstract: A method of making a high strength low-alloy steel includes the steps of casting an alloy steel into a cast form, hot rolling the cast form into a partially rolled form, and control rolling the partially rolled form to a rolled product. The controlled rolling is discontinued at a discontinue rolling temperature and is then acceleratedly cooled to a finish cooling temperature. The alloy steel uses a low silicon, carbon niobium, vanadium, titanium-containing steel composition. Silicon is less than 0.04% by weight, vanadium is between 0.05 and 0.10% by weight, niobium is between 0.06 and 0.14% by weight, titanium is between 0.006 and 0.02% by weight, and carbon is between 0.06 and 0.14% by weight. The controlled chemistry, controlled rolling, and accelerated cooling allows the discontinue rolling temperature to be high, thereby improving rolling productivity. The low-carbon alloy chemistry results in improvements in castability, formability, and weldability.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: August 7, 2001
    Assignee: Bethlehem Steel Corporation
    Inventors: Richard L. Bodnar, Yulin Shen
  • Patent number: 6248191
    Abstract: A method is provided for producing an ultra-high strength 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.) of at least about 120 joules (90 ft-lbs), and a microstructure comprising predominantly fine-grained lower bainite, fine-grained lath martensite, or mixtures thereof, transformed from substantially unrecrystallized austenite grains and comprising iron and specified weight percentages of the additives: carbon, silicon, manganese, copper, nickel, niobium, vanadium, molybdenum, chromium, titanium, aluminum, calcium, Rare Earth Metals, and magnesium.
    Type: Grant
    Filed: July 28, 1998
    Date of Patent: June 19, 2001
    Assignees: ExxonMobil Upstream Research Company, Nippon Steel Corporation
    Inventors: Michael J. Luton, Jayoung Koo, Narasimha-Rao V. Bangaru, Clifford W. Petersen, Hiroshi Tamehiro, Hitoshi Asahi, Takuya Hara, Masaaki Sugiyama
  • Patent number: 6224824
    Abstract: Disclosed is an alloy steel of high corrosion resistance to hot molten salts containing chlorides and/or alkali oxides. The alloy steel is manufactured from a composition comprising 20-40 weight % of Ni, 0-8 weight % of Cr, 0.05 weight % or less of C, 0.5 weight % or less of Si, 1.0 weight % or less of Mn, 0.05 weight % or less of S, and the balance of Fe to total weight. With a low Cr content, the alloy steel is superb in the corrosion resistance to chloride and/or alkali oxide-containing molten salts, including LiCl—Li2O. Also, the alloy steel shows stable corrosion resistance to molten salts even at high temperature as well as low temperature in addition to being superior to workability. Thus, the alloy steel can be processed into plates, bars or pipes which are used for structural materials and structural components for treating molten salts.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: May 1, 2001
    Assignee: Korea Electric Power Corporation
    Inventors: Jun Shan Zhang, Young Joon Shin, Soo Haeng Cho, Hyun Soo Park
  • Patent number: 6217680
    Abstract: A steel slab having a composition that comprises at most 0.008% by weight of C, at most 0.5% by weight of Si, at most 1.0% by weight of Mn, at most 0.15% by weight of P, at most 0.02% by weight of S, from 0.01 to 0.10% by weight of Al, at most 0.008% by weight of N, from 0.035 to 0.20% by weight of Ti, and from 0.001 to 0.015% by weight of Nb, with a balance of Fe and inevitable impurities, in which those C, S, N, Ti and Nb satisfy the following condition: 1.2(C/12+N/14+S/32)<(Ti/48+Nb/93), is subjected to rough hot-rolling to a reduction ratio of not lower than 85%, at a temperature falling between the Ar3 transformation point of the steel and 950° C., then to finishing hot-rolling to a reduction ratio of not lower than 65%, at a temperature falling between. 600° C. and the Ar3 transformation point of the steel, while being lubricated, to thereby have a mean shear strain of not larger than 0.06, then pickled, pre-annealed at a temperature falling between 700 and 920° C.
    Type: Grant
    Filed: March 15, 1999
    Date of Patent: April 17, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Yoshikazu Kawabata, Kaneharu Okuda, Kei Sakata, Takashi Obara, Atsushi Ogino
  • Patent number: 6171416
    Abstract: At least both ends of a sheet bar in the length direction, which is obtained by roughly rolling a steel slab including 0.1 wt % or less of C, 0.5 wt % or less of Si, 1.0 wt % or less of Mn, 0.1 wt % or less of P, 0.05 wt % or less of S, 0.20 wt % or less of Al, and 0.015 wt % or less of N, are heated so that the temperature at both ends of the sheet bar in the length direction is 15° C. or more higher than the temperature of the remainder of the sheet bar. The rolling finish temperature is Ar3+20° C. to Ar3+100° C. in both end portions of the sheet bar in the length direction, and Ar3+10° C. to Ar3+60° C. in the remainder, and the rolling finish temperature in the both end portions in the length direction is 10° C. or more higher than that of the remainder, so that a steel strip after cold rolling and annealing has r values within ±0.3 of the average r value, and &Dgr;r within ±0.
    Type: Grant
    Filed: October 26, 1999
    Date of Patent: January 9, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Makoto Aratani, Yukio Kobata, Hideo Kuguminato, Akio Tosaka, Masatoshi Aratani, Susumu Okada
  • Patent number: 6108894
    Abstract: A striker for use in a door latch apparatus comprises a base made of a normal-strength steel plate having a strength of 30 to 40 kg/mm.sup.2 and a U-shaped member made of a high-strength steel rod having a strength equal to or higher than 70 kg/mm.sup.2. The U-shaped member has inner and outer flanges, between which the base is firmly sandwiched. The inner flanges are formed without being heated. The U-shaped member is fixed to the base after hardened and tempered. After the U-shaped member is connected with the base, the base is not hardened or is not tempered.
    Type: Grant
    Filed: April 30, 1996
    Date of Patent: August 29, 2000
    Assignee: Mitsui Kinzoku Kogyo Kabushiki Kaisha
    Inventors: Tetsuro Mizuki, Hitoshi Tsuji, Koji Chikata
  • Patent number: 6099669
    Abstract: Composition segregation which results in streaks in an Fe--Ni alloy sheet shadow-mask is prevented by the following conditions. Heat-treatment from 1150.degree. C. to a temperature lower than the melting point for longer than 1 hour and not longer than 30 hours. Subsequent rough-rolling or forging at a reduction of area of 40% or more. A slab is subjected to removal of oxide scale on its surface and then heated in hydrogen atmosphere having dew point of 10.degree. C. or lower at a temperature of not less than 1100.degree. C. and lower than the melting point for time (t - hour) which is defined by:t.gtoreq.[3.8.times.10.sup.-7 exp (23830/T)]/R,where R is reduction area (%) at the slab production.
    Type: Grant
    Filed: March 7, 1997
    Date of Patent: August 8, 2000
    Assignee: Nippon Mining & Metals Co., Ltd.
    Inventors: Norio Yuki, Toshiyuki Ono, Tetsuo Kawahara
  • Patent number: 6042662
    Abstract: This process makes it possible to manufacture articles of any shape by stamping, in which articles the matrix of the alloy has to have a coarse-grained structure. According to the invention, a partial hot-forming operation is carried out by stamping a blank made of an oxide-dispersion-strengthened alloy, especially a nickel-based alloy, having an initial ultrafine-grained structure, in order to form a shaped component, this shaped component is subjected to a secondary recrystallization heat treatment so as to develop an abnormal grain growth, and then a new hot-forming operation is carried out by stamping in order to give the recrystallized shaped component the final shape of the article.
    Type: Grant
    Filed: June 18, 1998
    Date of Patent: March 28, 2000
    Assignee: SEVA
    Inventor: Jean-Paul Bagard
  • Patent number: 5885370
    Abstract: 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: Grant
    Filed: April 13, 1998
    Date of Patent: March 23, 1999
    Assignee: Kawasaki Steel Corporation
    Inventors: Michio Shimotomai, Akihiro Matsuzaki, Yasunori Yonehana
  • Patent number: 5827379
    Abstract: An extra high tensile steel having an excellent stress corrosion cracking resistance in sea water and a yield strength of 1080 MPa or more is provided. A slab comprising, in terms of % by weight, 0.04 to 0.09% of C, 0.01 to 0.10% of Si, 0.05 to 0.65% of Mn, 8.0 to 11.0% of Ni, 0.5 to 1.5% of Mo, 0.2 to 1.5% of Cr, 0.02 to 0.20% of V and 0.01 to 0.08% of Al with the balance consisting of iron and unavoidable impurities is heated to a temperature between 1000.degree. C. and 1250.degree. C., hot rolled at a temperature of Ar' point or above, air-cooled, reheated at a rate of 120.degree. C./min or less to a temperature region of from (A.sub.C3 point--40.degree. C.) to (A.sub.C3 point+40.degree. C.), quenched and subsequently tempered at a temperature of the A.sub.C1 point or below.
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: October 27, 1998
    Assignees: Nippon Steel Corporation, Kawasaki Steel Corporation
    Inventors: Yoshihiro Okamura, Ryota Yamaba, Tomoya Koseki, Ichiro Nakagawa
  • Patent number: 5725697
    Abstract: A method of manufacturing a cold-rolled can steel sheet having less planar anisotropy and achieving good workability. Rough-rolling is first performed on a continuously-cast slab. The slab has a composition essentially consisting of: C: 0.004 wt % or lower; Mn: 0.05-0.5 wt %; P: 0.02 wt % or lower; Al: 0.005-0.07 wt %; N: 0.004 wt % or lower; and Nb: 0.001-0.018 wt %, the rest being Fe and unavoidable impurities. A resultant sheet bar is then subjected to hot rolling which is completed at a finishing rolling temperature at an Ar.sub.3 transformation point or higher. The resultant sheet bar is coiled at a temperature range from 450.degree.-700.degree. C. Subsequently, the resultant sheet bar undergoes primary cold rolling before continuous annealing, which is performed at a recrystallization temperature or higher, and secondary cold rolling. The primary and secondary cold rolling are respectively performed at reduction ratios satisfying the following conditions of:88%.gtoreq.CR.sub.1 %+0.36.times.CR.sub.2 .
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: March 10, 1998
    Assignee: Kawasaki Steel Corporation
    Inventors: Chikako Fujinaga, Akio Tosaka, Toshiyuki Kato, Kaku Sato, Hideo Kuguminato
  • Patent number: 5716468
    Abstract: A rotor forging composed of Cr--Mo--V type alloy based on iron is normalizing-treated at a temperature of from 1000 to 1150.degree. C., the temperature is maintained at 650.degree.-750.degree. C. on the way of cooling the temperature from the normalizing-treating temperature to pearlite transform the microstructure of the rotor forging, the portions of the rotor forging corresponding to a high pressure or middle pressure portion are quenched at 940.degree.-1020.degree. C. and the portion corresponding to the low pressure portion is quenched at 850.degree.-940.degree. C. after the heat treatment is carried out at 920.degree.-950.degree. C. once or more times, and the rotor forging is subjected to tempering at 550.degree.-700.degree. C. once or more times. A high creep strength at the high and middle pressure portions can be obtained and, at the same time, the toughness at the low pressure portion is drastically enhanced.
    Type: Grant
    Filed: December 21, 1995
    Date of Patent: February 10, 1998
    Assignees: The Japan Steel Works, Ltd., Kabushiki Kaisha Toshiba
    Inventors: Yasuhiko Tanaka, Yasumi Ikeda, Tsukasa Azuma, Masayuki Yamada, Yoichi Tsuda
  • Patent number: 5660648
    Abstract: The present invention provides a steel material for a microalloyed part having a high strength in a hot worked state. A microalloyed steel for a high strength hot forging comprising specified amounts of C, Si, Mn, Cr, S, V and N, and Al and/or Ti, having a carbon equivalent in a definite range, and exhibiting a bainite transformation starting point in a definite range. A microalloyed steel for a high strength hot forging comprising specified amounts of C, Si, Mn, Cr, S, V, N and Ca, and Al and/or Ti, having a carbon equivalent in a definite range, and exhibiting a bainite transformation starting point in a definite range. Said steel material has a tensile strength of at least 900 MPa when it is in a hot forged, and non-quenched and tempered state. Automobile parts can be made small and light by the use of the steel of the invention.
    Type: Grant
    Filed: January 5, 1995
    Date of Patent: August 26, 1997
    Assignee: Nippon Steel Corporation
    Inventors: Hiromasa Takada, Yoshiro Koyasu, Motohide Mori, Masami Suzuki
  • Patent number: 5637161
    Abstract: A method for manufacturing an alloy sheet for a shadow mask is provided which includes: (i) annealing a hot-rolled sheet containing Fe and Ni at a temperature of 910.degree. to 990.degree. C.; (ii) cold-rolling the annealed hot-rolled sheet from step (i) to produce a cold-rolled sheet; (iii) crystallization annealing of the cold-rolled sheet from step (ii); (iv) cold-rolling the annealed cold rolled sheet from step (iii); (v) finish recrystallization annealing step of the cold-rolled sheet of step (iv); (vi) finish cold-rolling of the sheet from step (v) at a cold-rolling reduction ratio R (%) satisfying the following equations: 16.ltoreq.R.ltoreq.75 and 6.38 D-133.9.ltoreq.R.ltoreq.6.38 D-51.0 wherein D is the average austenite grain size in .mu.m; (vii) softening annealing the sheet from step (vi) at a temperature of 720.degree. to 790.degree. C. for 2 to 40 minutes before press-forming and at conditions of temperature T in .degree.C. and time t in minutes which satisfy the following equation :T.gtoreq.-53.
    Type: Grant
    Filed: April 25, 1995
    Date of Patent: June 10, 1997
    Assignee: NKK Corporation
    Inventors: Tadashi Inoue, Kiyoshi Tsuru, Michihito Hiasa, Tomoyoshi Okita
  • Patent number: 5545269
    Abstract: High strength steel is produced by a first rolling of a steel composition, reheated above 1100.degree. C., above the austenite recrystallization, a second rolling below the austenite recrystallization temperature, water cooling from above Ar.sub.3 to less than 400.degree. C. and followed by tempering below the Ac.sub.1 transformation point.
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: August 13, 1996
    Assignee: Exxon Research and Engineering Company
    Inventors: Jayoung Koo, Michael J. Luton
  • Patent number: 5542995
    Abstract: 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: Grant
    Filed: December 16, 1993
    Date of Patent: August 6, 1996
    Inventor: Robert Reilly
  • Patent number: 5531842
    Abstract: A high strength steel composition comprising ferrite and martensite/bainite phases, the ferrite phase having primarily vanadium and niobium carbide or carbonitride precipitates, is prepared by a first rolling above the austenite recrystallization temperature, a second rolling below the austenite recrystallization temperature; cooling between the Ar.sub.3 transformation point and 500.degree. C.; and water cooling to below about 400.degree. C.
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: July 2, 1996
    Assignee: Exxon Research and Engineering Company
    Inventors: Jayoung Koo, Michael J. Luton
  • Patent number: 5492576
    Abstract: A clutch diaphragm comprises a peripheral Belleville ring portion and a central portion having a central aperture and comprising a set of radial fingers separated by slots, each of which extends from a blind end which is close to the peripheral portion to an inner end which is open into the central aperture, the latter being common to all of the slots.In a method of making this diaphragm, a flat blank is heat treated and is then soaked and hot formed to give the diaphragm a first diaphragm angle. It is then tempered in a tempering oven. The diaphragm is then transferred from the tempering oven to a stabilizing press, in which the conicity of the diaphragm is reversed while it is still hot from the tempering oven, so that instead of the first angle it now has an inversion angle.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: February 20, 1996
    Assignee: Valeo
    Inventors: Patrick Jehl, Jean-Pierre Vrinat
  • Patent number: 5476556
    Abstract: Graphite steel for a machine structural use exhibiting excellent cutting characteristic, cold forging characteristic and fatigue resistance, the graphite steel for a machine structural use containing: C: 0.1 wt % to 1.5 wt %; Si: 0.5 wt % to 2.0 wt %; Mn: 0.1 wt % to 2.0 wt %; B: 0.0003 wt % to 0.0150 wt %; Al: 0.005 wt % to 0.1 wt %; O.ltoreq.0.0030 wt %; P.ltoreq.0.020 wt %; S.ltoreq.0.035 wt %; N: 0.0015 wt % to 0.0150 wt %; and a balance consisting of Fe and unavoidable impurities, wherein substantially overall quantity of C is precipitated as graphite and size of graphite is 20 .mu.m or less.
    Type: Grant
    Filed: August 1, 1994
    Date of Patent: December 19, 1995
    Assignee: Kawasaki Steel Corporation
    Inventors: Toshiyuki Hoshino, Takashi Iwamoto, Akihiro Matsuzaki, Keniti Amano
  • Patent number: 5458704
    Abstract: The invention relates to a process for the production of very hard armour plates from steel slabs, wherein the slabs are hot rolled to a final thickness above 50 mm and then hardened and possibly tempered. The characterizing feature of the invention is that a continuously cast slab is produced from a steel having0.25 to 0.32% C0.05 to 0 75% Si0.10 to 1.50% Mn0.90 to 2.00% Cr0.10 to 0.70% Mo1 20 to 4 50% Ni0.01 to 0.08% Almax 0.015% Pmax 0.005% Smax 0.012% Nresidue Fe, including usual impurities,the slab then being heated to a temperature of 1150.degree. C. or higher and heated through, whereafter following cooling in air and by the spraying of its two wide sides with pressurized water, the slab is hot rolled with a surface temperature in the range of 1050.degree. to 900.degree. C. in shaping passes having an individual deformation of .epsilon..sub.h >0.1 and with a shape factor SF>0.40 to the final thickness.
    Type: Grant
    Filed: November 12, 1993
    Date of Patent: October 17, 1995
    Assignee: Thyssen Stahl AG
    Inventors: Jochen Bobbert, Rudolf Kawalla, Hans Pircher, Gerd Sussek, Gunter Weihrauch
  • Patent number: 5447581
    Abstract: An extra high tensile steel having an excellent stress corrosion cracking resistance and a yield strength of 1080 MPa or more is provided. A slab comprising, in terms of % by weight, 0.03 to 0.08% of C, 0.01 to 0.10% of Si, 0.05 to 0.65% of Mn, 8.0 to 11.0% of Ni, 0.5 to 1.5% of Mo, 0.2 to 1.5% of Cr, 0.02 to 0.20% of V and 0.01 to 0.08% of Al with the balance consisting of iron and unavoidable impurities is heated to a temperature between 1000.degree. C. and 1250.degree. C., hot-rolled in an austenite recrystallization temperature region with a reduction ratio of 30 to 70%, subsequently rolled in an austenite nonrecrystallization temperature region with a reduction ratio of 20 to 60%, subjected to roll finishing, water-cooled from a temperature of 600.degree. C.
    Type: Grant
    Filed: October 28, 1993
    Date of Patent: September 5, 1995
    Assignee: Nippon Steel Corporation
    Inventors: Yoshihiro Okamura, Ryota Yamaba
  • Patent number: 5421920
    Abstract: After a predeoxidation treatment of a molten steel comprising as basic ingredients, in terms of % by weight, 0.04 to 0.20% of C, 0.05 to 0.50% of Si, 0.4 to 2.0% of Mn, 0.3 to 0.7% of Mo, 0.003 to 0.015% of N, 0.04 to 0.20% of V and less than 0.005% of Al to regulate [O %] to 0.003 to 0.015% by weight, titanium is added thereto so as to satisfy a requirement represented by the formula: -0.006.ltoreq.[Ti %]-2[O %].ltoreq.0.008 to crystallize a titanium-based oxide in an amount of 20 particles/mm.sup.2 or more, and MnS, TiN and V(C, N) are deposited on the titanium-based oxide to disperse the titanium-based oxide as a composite precipitate in the steel to provide a cast slab, and a high-strength high-toughness shape steel having an excellent fire resistance is provided by a combination of water cooling between rolling passes at the time of rolling with accelerated cooling after the completion of the rolling.
    Type: Grant
    Filed: September 20, 1993
    Date of Patent: June 6, 1995
    Assignee: Nippon Steel Corporation
    Inventors: Kohichi Yamamoto, Suguru Yoshida, Kazuo Watanabe
  • Patent number: 5409554
    Abstract: A process for improving the impact properties of high-strength steels containing grain-refining additions is disclosed along with a product made in accordance therewith. The process comprises a pretreatment step involving heating and hot deformation at a temperature preferably in excess of the solution temperature of the least soluble nitride or carbonitride species present in the steel (T .gtoreq..apprxeq.1200.degree. C.) followed by accelerated cooling, such as by water quenching, oil quenching, or forced-air cooling. Thereafter, the material is subjected to a subcritical annealing treatment (.apprxeq.700.degree. C.), austenitized at low-to-moderate temperatures of between about 850.degree.-950.degree. C., and then quenched and tempered.
    Type: Grant
    Filed: September 15, 1993
    Date of Patent: April 25, 1995
    Assignee: The Timken Company
    Inventor: Michael J. Leap
  • Patent number: 5360493
    Abstract: In a method of producing a high-strength cold-rolled steel sheet excelling in deep drawability, a steel material is used which consists of: a basic composition including 0.01% or less of C, 0.1 to 2.0% of Si, 0.5 to 3.0% of Mn, 0.02 to 0.2% of P, 0.05% or less of S, 0.03 to 0.2% of Al, 0.01% or less of N, 0.001 to 0.2% of Nb, and 0.0001 to 0.008% of B in such a way that the respective contents of C, Nb, Al, N, Si, Mn and P satisfy the following formulae:5.ltoreq.Nb/C.ltoreq.30, 10.ltoreq.Al/N.ltoreq.80, and 16.ltoreq.(3.times.Si/28+200 .times.P/31)/(Mn/55).ltoreq.40; Fe remnant; and inevitable impurities, the method including the steps of:performing rolling on the steel material with a total reduction of 50% or more and 95% or less while effecting lubrication thereon in a temperature range of not higher than the Ar.sub.3 transformation temperature and not lower than 500.degree. C.
    Type: Grant
    Filed: June 7, 1993
    Date of Patent: November 1, 1994
    Assignee: Kawasaki Steel Corporation
    Inventors: Saiji Matsuoka, Hidetaka Kawabe, Eiko Yasuhara, Kei Sakata, Toshiyuki Kato
  • Patent number: 5358578
    Abstract: In a process for producing high-strength, corrosion-resistant and brittle fracture-resistant prestressing steels, there is a fine grain and/or solid solution and/or particle or precipitation hardening, linked with a thermodynamic treatment and subsequent strain hardening. As strengthening measures are used both a solid solution, fine grain and particle or precipitation hardening with a substantially additive effect. The thermomechanical treatment is performed by a controlled rolling of microalloyed, fine grain-melted steels, whilst excluding martensite formation.
    Type: Grant
    Filed: January 12, 1993
    Date of Patent: October 25, 1994
    Inventor: Max W. Tischhauser
  • Patent number: 5238511
    Abstract: A double C-shaped, resilient, biased clamp for fixing a track rail to a support is manufactured by bending a piece of bar material to a double C-shape. Thereafter the clamp is hardened and heat treated. Prior to bending heating takes place at approximately 1200.degree. C. and finishing takes place directly thereafter by a starting temperature of 900.degree.-1000.degree. C. By this a spring of smaller dimensions is obtained. However, with almost the same properties as the clamps as produced previously.
    Type: Grant
    Filed: February 4, 1992
    Date of Patent: August 24, 1993
    Assignee: Everts en Van der Weyden Exploitatiemaatschappij
    Inventor: Addick A. Gosling
  • Patent number: 5209900
    Abstract: A high-fineness shadow mask material comprising 33-40% by weight of Ni, 0.0001-0.0015% by weight of one or more of boron, magnesium and titanium, and the remainder consisting essentially of Fe, wherein the contents of sulfur and aluminum are confined to not more than 0.0020% and not more than 0.020% by weight, respectively, and a process for producing the material. The shadow mask material according to this invention is excellent in hot working property and in etching properties.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: May 11, 1993
    Assignee: Hitachi Metals, Ltd.
    Inventors: Shuichi Nakamura, Hakaru Sasaki
  • Patent number: 5139581
    Abstract: A method for producing moldboard for use with plows and the like employs a process whereby the moldboards are shot peened under closely controlled conditions to form a textured, pocked contour across the working surface of the moldboard. This surface structure allows for several prior art steps to be eliminated, and also facilitates the scouring of the moldboard when it is first used thereby allowing the moldboard to scour until a working finish is established on the working surface of the moldboard.
    Type: Grant
    Filed: October 3, 1990
    Date of Patent: August 18, 1992
    Assignee: Case Corporation
    Inventors: William L. Grimm, William A. Stewart
  • Patent number: 5139583
    Abstract: A graphite precipitated hot-rolled steel plate having excellent bending workability and hardenability, the graphite precipitated hot-rolled steel plate comprising: 0.1 to 1.0% (by weight percent) C; 0.05 to 1.0% (by weight percent) Mn; 3 to 50 ppm B; 200 ppm or less N the quantity of which is three times or more the quantity of B; and a balance of Fe and unavoidable impurities, wherein graphite the diameter of which is 5 .mu.m or less is precipitated in such a manner that distance between graphite particles is at a distance of 5 .mu.m or longer.
    Type: Grant
    Filed: January 21, 1992
    Date of Patent: August 18, 1992
    Assignee: Kawasaki Steel Corporation
    Inventors: Yoshikazu Kawabata, Masahiko Morita, Fusao Togashi
  • Patent number: 5123970
    Abstract: 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 2o 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: Grant
    Filed: May 4, 1990
    Date of Patent: June 23, 1992
    Assignee: Qinghua University
    Inventors: Hongsheng Fang, Yankang Zheng, Xiuyun Chen, Donghao Chen, Rufa Zhao
  • Patent number: 5122336
    Abstract: The invention relates to a high-hardness steel for armouring having the following chemical composition by weight: 0.4 to 0.7% of carbon, 0.3 to 1.5% of manganese, 0.1 to 2% of chromium, 0.5 to 1.5% of silicon, 1 to 5% of nickel, 0.2 to 1% of molybdenum, less than 0.015% of phosphorus and less than 0.005% of sulphur, the remainder being iron and residual impurities resulting from the smelting of the materials necessary for the production.The invention also relates to a process for the production of such a steel.
    Type: Grant
    Filed: October 9, 1990
    Date of Patent: June 16, 1992
    Assignee: Creusot-Loire Industrie
    Inventors: Remi Roux, Laurent Sangoy, J. Henri Leger
  • Patent number: 5110375
    Abstract: An expandable baton is constructed of heat treatable alloy steel and is formed according to a method which provides both ease of workability of the component materials and strength for the resultant baton. The disclosed method comprises the steps of first forming the sections from heat treatable alloy steel, then annealing the baton components to soften them, then forming the components into the desired shapes, and finally hardening the components. The resulting baton provides the strength and reliability required in such a device.
    Type: Grant
    Filed: August 22, 1991
    Date of Patent: May 5, 1992
    Inventor: Kevin L. Parsons