Heating Step Follows Cooling Patents (Class 148/662)
  • Patent number: 10408268
    Abstract: A pressure nitrided stainless steel hybrid ball bearing having an inner ring, an outer ring, and rolling elements disposed therebetween. The pressure nitrided stainless steel hybrid bearing has one or more component(s) made from a pressure nitrided stainless steel material. The pressure nitrided stainless steel hybrid bearing used with a refrigerant lubrication for chiller applications leads to a very long useful life time.
    Type: Grant
    Filed: January 24, 2014
    Date of Patent: September 10, 2019
    Assignee: TRANE INTERNATIONAL INC.
    Inventors: William E. Lapp, Todd W. Smith, Arthur L. Butterworth, Paul J. Sikorsky
  • Patent number: 8926768
    Abstract: A steel for spring includes C: 0.5 to 0.6%, Si: 1.0 to 1.8%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.0%, P: 0.035% or less, S: 0.035% or less, by mass %, and a balance of iron and inevitable impurities, as the overall composition, wherein an area ratio of an internal structure on an optional cross section comprises bainite: 65% or more, retained austenite: 6 to 13%, and a balance of martensite, and average C content in the retained austenite is 0.65 to 1.7%. The steel for spring can have high strength in which tensile strength is 1800 MPa or more and have high ductility.
    Type: Grant
    Filed: March 8, 2010
    Date of Patent: January 6, 2015
    Assignee: NHK Spring Co., Ltd.
    Inventors: Takeshi Suzuki, Yoshiki Ono
  • Patent number: 8864922
    Abstract: A method for manufacturing a precipitation hardening cold-rolled steel sheet with an excellent yield ratio. The method may include the steps of hot rolling a steel slab with finish rolling at a temperature of Ar3 transformation point or more to form a hot-rolled steel sheet, coiling the hot-rolled steel sheet at a temperature of 550-600 ° C., cold rolling the hot-rolled steel sheet at a reduction ratio of 50% or more; and recovery-recrystallization annealing the cold-rolled steel sheet at a line speed of 150-200 mpm and at a temperature of 780-820° C. in a continuous annealing furnace. The recovery-recrystallization annealing may provide a recrystallization ratio of 65-75%. The steel slab includes, by weight %: C: 0.07-0.10%, Mn: 1.41-1.70%, P: 0.05-0.07%, S: 0.005% or less, N: 0.005% or less, acid-soluble Al: 0.10-0.15%, Nb: 0.06-0.09%, B: 0.0008-0.0012%, Sb: 0.02-0.06%, and the balance comprising Fe and other unavoidable impurities.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: October 21, 2014
    Assignee: POSCO
    Inventor: Sang-Ho Han
  • Patent number: 8845831
    Abstract: There is provided a heat treatment method in which high-quality tempering treatment can be performed in a short period of time. In this method, when an object to be treated is tempered after being quenched, the object to be treated is rapidly cooled to a 90% martensite transformation finishing temperature without being cooled to the ordinary temperature after quench heating, and then is subjected to 100% martensite transformation by using a 100° C. liquid, and thereafter, tempering treatment is performed after the whole of the object to be treated is soaked by using the 100° C. liquid.
    Type: Grant
    Filed: February 2, 2009
    Date of Patent: September 30, 2014
    Assignee: Denki Kogyo Co., Ltd.
    Inventors: Seiichi Sawatsubashi, Keiichi Kubo
  • Patent number: 8518195
    Abstract: The microstructure of a low alloy steel workpiece for cold forming may be beneficially modified by heating the workpiece to a temperature just above its austenite transformation temperature (Ac3 temperature). The steel workpiece is then cooled just below its Ac3 temperature to promote ferrite formation on and between the austenite grains. Heating and cooling, above and below the Ac3 temperature, is repeated a determined number of times to refine the austenite grains before the workpiece is quenched below its martensite transformation temperature to form a mixture of martensite with increased retained austenite. The workpiece may be further heated in its martensite region to increase the proportion of retained austenite before quenching the steel workpiece to an ambient temperature. The formability of the workpiece is improved, as is the strength of its formed shape.
    Type: Grant
    Filed: January 20, 2012
    Date of Patent: August 27, 2013
    Assignee: GM Global Technology Operations LLC
    Inventor: John R. Bradley
  • Publication number: 20130180628
    Abstract: A method of fabricating a martensitic stainless steel including: 1) heating steel to a temperature higher than austenizing temperature of the steel, then quenching the steel until a hottest portion of the steel is at a temperature less than or equal to a maximum temperature, and greater than or equal to a minimum temperature, a cooling rate being sufficiently fast for austenite not to transform into a ferrito-perlitic structure; 2) performing a first anneal followed by cooling until the hottest portion of the steel is at a temperature less than or equal to the maximum temperature and greater than or equal to the minimum temperature; 3) performing a second anneal followed by cooling to ambient temperature; and at the end of each of 1) and 2), performing: ?) as soon as temperature of the hottest portion of the steel reaches the maximum temperature, immediately heating the steel once more.
    Type: Application
    Filed: September 8, 2011
    Publication date: July 18, 2013
    Applicant: SNECMA
    Inventors: Jean-François Laurent Chabot, Laurent Ferrer, Pascal Charles Emile Thoison
  • Patent number: 8313589
    Abstract: An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel excellent in high-pressure hydrogen environment embrittlement resistance characteristics, which is characterized in that the steel has a composition comprising C: 0.10 to 0.20%, Si: 0.10 to 0.40%, Mn: 0.50 to 1.20%, Cr: 0.20 to 0.80%, Cu: 0.10 to 0.50%, Mo: 0.10 to 1.00%, V: 0.01 to 0.10%, B: 0.0005 to 0.005% and N: 0.01% or less, by mass, with the balance consisting of Fe and unavoidable impurities.
    Type: Grant
    Filed: August 21, 2008
    Date of Patent: November 20, 2012
    Assignee: The Japan Steel Works, Ltd.
    Inventors: Koichi Takasawa, Yoru Wada, Ryoji Ishigaki, Yasuhiko Tanaka
  • Patent number: 8241559
    Abstract: The invention relates to a steel material having a high silicon content, and to a method for the production thereof, the steel material being particularly suitable for piston rings and cylinder sleeves. In addition to iron and production-related impurities, the steel material contains 0.5 to 1.2 wt. % carbon, 3.0 to 15.0 wt. % silicon and 0.5 to 4.5 wt. % nickel. Also, the steel material can contain small amounts of the following elements Mo, Mn, Al, Co Nb, Ti, V, Sn, Mg, B, Te Ta La, Bi, Zr, Sb, Ca, Sr, Cer, rare earth metals and nucleating agents such as NiMg, MiSiMg, FeMg and FeSIMg. due to the high Si content, a degree of saturation higher than 1.0 is attained, with the melting temperature of the steel material corresponding to normal cast iron. The steel material can be produced according to a conventional cast-iron technique and has a high resistance to wear and tear and a high structural strength (minimal distortion).
    Type: Grant
    Filed: May 7, 2007
    Date of Patent: August 14, 2012
    Assignee: Federal-Mogul Burscheid GmbH
    Inventor: Laszlo Pelsoeczy
  • Patent number: 8147626
    Abstract: A high strength steel plate containing 0.02 to 0.08% C, by mass, and has substantially a two phase microstructure of ferrite and bainite. The ferrite contains precipitates having a particle size of 30 nm or smaller grain size. The steel plate has a yield strength of 448 MPa or higher. A method for manufacturing the high strength steel plate which comprises hot rolling, accelerated cooling and reheating. The accelerated cooling is conducted down to a temperature of 300 to 600° C. at a cooling rate of 5° C./s or higher. The reheating is conducted up to a temperature of 550 to 700° C. at a heating rate of 0.5° C./s or higher.
    Type: Grant
    Filed: March 22, 2011
    Date of Patent: April 3, 2012
    Assignee: JFE Steel Corporation
    Inventors: Nobuyuki Ishikawa, Toyohisa Shinmiya, Minoru Suwa, Shigeru Endo
  • Publication number: 20120042994
    Abstract: To provide a technique suitable for elevating strength and toughness of a thin low-carbon steel. By performing rapid heating and rapid cooling to a thin low-carbon steel which is an ordinary steel with a thickness of 1.2 mm or less, a steel where a microstructure becomes a duplex grain size structure mixed with crystal grains having different grain diameters, which is not homogeneous, preferably, hard phase structures are contained in addition to the duplex grain size structure is obtained, and a high-strength and high-toughness thin low-carbon steel is obtained. Further, by performing a heat treatment process involving rapid heating and rapid cooling multiple times, a duplex grain size structure of crystal grains with smaller grain diameters or a hard phase structure contained therein is obtained, so that a thin low-carbon steel with higher strength and higher toughness is obtained.
    Type: Application
    Filed: February 22, 2010
    Publication date: February 23, 2012
    Applicant: Delta Tooling Co., Ltd.
    Inventors: Etsunori Fujita, Yumi Ogura, Seiji Kawasaki, Shigeyuki Kojima, Soichi Makita, Shigeru Maeda, Hideyuki Yamane, Seiya Yoshida
  • Publication number: 20120024436
    Abstract: A steel for spring includes C: 0.5 to 0.6%, Si: 1.0 to 1.8%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.0%, P: 0.035% or less, S: 0.035% or less, by mass %, and residue consisting of iron and inevitable impurities, as the overall composition, wherein an area ratio of an internal structure on an optional cross section comprises bainite: 65% or more, retained austenite: 6 to 13%, and martensite: residue (including 0%), and average C content in the retained austenite is 0.65 to 1.7%. The steel for spring can have high strength in which tensile strength is 1800 MPa or more and have high ductility.
    Type: Application
    Filed: March 8, 2010
    Publication date: February 2, 2012
    Applicant: NHK SPRING CO., LTD.
    Inventors: Takeshi Suzuki, Yoshiki Ono
  • Patent number: 8048237
    Abstract: An ultra soft high carbon hot-rolled steel sheet has excellent workability. The steel sheet is a high carbon hot-rolled steel sheet containing 0.2 to 0.7% C, and has a structure in which mean grain size of ferrite is 20 ?m or larger, the volume percentage of ferrite grains having 10 ?m or smaller size is 20% or less, mean diameter of carbide is in a range from 0.10 ?m to smaller than 2.0 ?m, the percentage of carbide grains having 5 or more of aspect ratio is 15% or less, and the contact ratio of carbide is 20% or less.
    Type: Grant
    Filed: February 26, 2007
    Date of Patent: November 1, 2011
    Assignee: JFE Steel Corporation
    Inventors: Hideyuki Kimura, Takeshi Fujita, Nobuyuki Nakamura, Naoya Aoki, Masato Sasaki, Satoshi Ueoka, Shunji Iizuka
  • Patent number: 7909950
    Abstract: The present invention provides an ultra soft high carbon hot-rolled steel sheet. The ultra soft high carbon hot-rolled steel sheet contains 0.2% to 0.7% of C, 0.01% to 1.0% of Si, 0.1% to 1.0% of Mn, 0.03% or less of P, 0.035% or less of S, 0.08% or less of Al, 0.01% or less of N, and the balance being Fe and incidental impurities and further contains 0.0010% to 0.0050% of B and 0.05% to 0.30% of Cr in some cases. In the texture of the steel sheet, an average ferrite grain diameter is 20 ?m or more, a volume ratio of ferrite grains having a grain diameter of 10 ?m or more is 80% or more, and an average carbide grain diameter is in the range of 0.10 to less than 2.0 ?m. In addition, the steel sheet is manufactured by the steps, after rough rolling, performing finish rolling at a reduction ratio of 10% or more and at a finish temperature of (Ar3?20° C.) or more in a final pass, then performing first cooling within 2 seconds after the finish rolling to a cooling stop temperature of 600° C.
    Type: Grant
    Filed: September 19, 2006
    Date of Patent: March 22, 2011
    Assignee: JFE Steel Corporation
    Inventors: Hideyuki Kimura, Takeshi Fujita, Nobuyuki Nakamura, Satoshi Ueoka, Naoya Aoki, Kenichi Mitsuzuka
  • Patent number: 7905967
    Abstract: The occurrence of delayed fracture which is found in a hot worked martensitic stainless steel is prevented by subjecting the steel, after hot working and prior to heat treatment for hardening by quenching from a temperature of at least Ac1 point of the steel, to preliminary softening heat treatment under such conditions that the softening parameter P defined below is at least 15,400 and the softening temperature T is lower than the Ac1 point: P(softening parameter):P=T(20+log t) T: softening temperature [K] t: duration of softening treatment [Hr]. The present invention is particularly effective for a martensitic stainless steel having a steel composition in which the amount of effective dissolved C and N (=[C*+10N*]) where C* and N* are calculated by the following formulas is larger than 0.45: C*=C?[12{(Cr/52)×(6/23)}/10, and N*=N?[14{(V/51)+(Nb/93)}/10]?[14{(Ti/48)+(B/11)+(Al/27)}/10].
    Type: Grant
    Filed: September 28, 2007
    Date of Patent: March 15, 2011
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventor: Nobuyuki Mori
  • Patent number: 7754031
    Abstract: The invention concerns weldable steel building components whereof the chemical composition comprises, by weight: 0.10%?C?0.22%, 0.50%?Si?1.50%, AI?0.9%, 0%?Mn?3%, 0%?Ni?5%, 0%?Cr?4%, 0%?Cu?1%, 0%?Mo+W/2?1.5%, 0.0005%?B<0.010%, N?0.025%, optionally at least one element selected among V, Nb, Ta, S et Ca, in contents less than 0.3%, and/or among Ti and Zr in contents not more than 0.5%, the rest being iron and impurities resulting from preparation, the aluminium, boron, titanium and nitrogen contents, expressed in thousandths of %, of said composition further satisfying the following relationship: B??×K+0.5, (1) with K=Min (I*; J*), I*=Max (0; I) and J*=Max (0; J), I=Min (N; N?0.29(Ti?5)), J=Min {N; 0.5 (N 0.52 AI+?j(N 0.52 AI)2+283)}, the silicon and aluminium contents of the composition additionally verifying the following conditions: if C>0.145, then Si+AI<0.95 and whereof the structure is bainitic, martensitic or martensitic/bainitic and further comprises 3 to 20% of residual austenite.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: July 13, 2010
    Assignee: Industeel Creusot
    Inventors: Jean Beguinot, Jean-Georges Brisson
  • Patent number: 7718018
    Abstract: A method of cooling both surfaces of steel plate, which stably secures precision of cooling control from a start of cooling to an end so as to uniformly cool the top and bottom surfaces of the steel plate and thereby stably secures the steel plate quality and cools the steel plate down to a target temperature with a good precision. The method comprises dividing a steel plate cooling region into at least a spray impact part region and a spray non-impact part region, predicting a heat transfer coefficient for each divided region in advance, computing a predicted temperature history of the steel plate based on this predicted value, and setting and controlling amounts of sprayed coolant on the spray impact part regions by top and bottom surface nozzles.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: May 18, 2010
    Assignee: Nippon Steel Corporation
    Inventors: Yoshihiro Serizawa, Ryuji Yamamoto, Shigeru Ogawa
  • Publication number: 20090314396
    Abstract: A method for heat treatment of steel and a system thereof is provided. First the steel is austenitized at a suitable temperature and then the temperature is rapidly brought down to the austempering temperature. Here the cyclic austempering is carried out between two austempering temperatures by modulating the temperature with controlled heating and cooling and the controlled temperature modulation is obtained by controlling the temperature-time profile in a batch furnace or by controlling the zone temperatures in a continuous furnace. This method of cyclic austempering reduces the austempering time, reduces the energy consumption and emissions, enhances the productivity and reduces the process cost.
    Type: Application
    Filed: August 1, 2008
    Publication date: December 24, 2009
    Inventors: Philip NASH, Vivekanand SISTA, Satyam Suraj SAHAY
  • Publication number: 20090272470
    Abstract: Method of heat treating cultivating disc, coulter or grain drill blades made from heat quenched boron steels, such that they can be re-edged and re-sharpened using rollers, and yet retain excellent toughness, hardness and wear characteristics. The invention also includes the cultivating disc, coulter or grain drill blades made from boron steel, which have been heat treated according to the inventive method, such that can be re-edged or sharpened using pinch rollers. The cultivating blades are especially useful in the dry, sandy soils such as found in the wheat growing regions extending from central Kansas down into Texas.
    Type: Application
    Filed: April 30, 2008
    Publication date: November 5, 2009
    Inventor: Douglas G. Bruce
  • Publication number: 20090223610
    Abstract: A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (Dave) of 20 ?m or less and a maximum crystal grain diameter (Dmax) of 120 ?m or less, preferably an area ratio of crystal grains having a diameter of 80 ?m or more of 40% or less, an average sub grain diameter (dave) of 10 ?m or less, a maximum sub grain diameter (dmax) of 50 ?m or less and a (Dave/dave) ratio of the average crystal grain diameter (Dave) to the average sub grain diameter (dave) of 4.5 or less.
    Type: Application
    Filed: May 15, 2009
    Publication date: September 10, 2009
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takuya KOCHI, Shogo MURAKAMI, Hiroshi YAGUCHI, Takeshi KURODA, Hidenori SAKAI, Tomotada MARUO, Takaaki MINAMIDA
  • Patent number: 6982012
    Abstract: A method of manufacturing a high strength steel sheet containing, in mass %, C: 0.02 to 0.04%, Si: at most 0.4%, Mn: 0.5-3.0%, P: at most 0.15%, S: at most 0.03%, Al: at most 0.50%, N: at most 0.01%, and Mo: 0.01-1.0%. The method includes performing hot rough rolling either directly or after heating to a temperature of at most 1300° C., commencing hot finish rolling either directly or after reheating or holding, completing finish rolling at a temperature of at least 780° C., performing coiling after cooling to a temperature of 750° C. or below at an average cooling rate of at least 3° C./second, heating to an annealing temperature of at least 700° C. and then cooling to a temperature of 600° C. or below at an average cooling rate of at least 3° C./second, then holding in a temperature range of 450-600° C. for at least 10 seconds, and performing hot dip galvanizing after cooling.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: January 3, 2006
    Assignee: Sumitomo Metal Industries Ltd.
    Inventors: Shigeki Nomura, Hiroyuki Nakagawa, Yoshiaki Nakazawa
  • Patent number: 6890665
    Abstract: Martensitic stainless steel whose steel composition is restricted within a specific range for each element is provided. The scale layer formed on the surface of the base material consists of an inner layer scale mainly including FeCr2O4 and an outer layer scale having a thickness of not more than 20 ?m, which outer layer is deposited on the inner layer scale at a surface coverage of not less than 1% and not more than 15%. The application of rust preventive oil onto the surface of the steel ensures an excellent weather resistance during a long term, and therefore a martensitic stainless steel forming no rust either in the outdoor depository or in the indoor depository can be provided. The steel can be used to manufacture, not only steel pipes, but also steel plates, steel rods and others in a wide application field.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: May 10, 2005
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventor: Mutsumi Tanida
  • Patent number: 6884306
    Abstract: A mainly bainitic steel having the following composition in weight percent: carbon 0.6-1.1; silicon 1.5 to 2.0; manganese 1.8 to 4.0; chromium 1.2 to 1.4; nickel 0-3; molybdenum 0.2 to 0.5; vanadium 0.1 to 0.2, balance iron save for incidental impurities.
    Type: Grant
    Filed: August 2, 2000
    Date of Patent: April 26, 2005
    Assignee: Qinetiq Limited
    Inventors: Kankanange J A Mawella, Francisca G Caballero, Harshad K D H Bhadeshia
  • Patent number: 6843867
    Abstract: A method of austempering of steel parts is described. The steel parts are initially austenitized and subsequently quenched to a start temperature which is higher than the martensite start temperature. Then the steel parts are subjected to a first isothermal holding at the start temperature for a first time period. Subsequently the steel parts are held for a second isothermal time period at a finish temperature which is higher than the start temperature. The method described is particularly well suited for rapid austempering of steel parts, a pure bainitic structure being achievable, and the core hardness of the steel parts obtained being settable via the start temperature, the finish temperature, the duration of the first time period, and the duration of the second time period.
    Type: Grant
    Filed: October 18, 2000
    Date of Patent: January 18, 2005
    Assignee: Robert Bosch GmbH
    Inventors: Lothar Foerster, Michael Michalski, Andreas Becht, Karl-Otto Englert, Michael Czeringer
  • Patent number: 6641931
    Abstract: The present invention aims to produce a cold rolled metal coated multi-phase steel, characterized by a tensile strength of at least 500 MPa, a yield ratio (Re/Rm) lower than 0.65 in skinned conditions, lower than 0.60 in unskinned conditions, and with good metal coating adhesion behavior. In the case of the aluminized steel according to the invention, the steel also has superior resistance to temperature corrosion up to 900° C. and excellent mechanical properties at this high temperature. The hot metal coated steel product having a steel composition with a manganese content lower than 1.5%, chrome content between 0.2 and 0.5%, molybdenum content between 0.1 and 0.25%, and a relation between the chrome and molybdenum content as follows Cr+2 Mo higher than or equal to 0.7%, undergoes a thermal treatment in the hot dip metal coating line defined by a soaking temperature between Ac1 and Ac3, a primary cooling speed higher than 25° C./sec and a secondary cooling speed higher than 4° C./sec.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: November 4, 2003
    Assignee: Sidmar N.V.
    Inventors: Serge Claessens, Dirk Vanderschueren
  • Patent number: 6632303
    Abstract: A grinding ball having a 55 to 65 Rockwell C hardened outer shell of tempered martensite is adapted for use in a heavy duty grinding environment by stress relieving to stabilize the ball against break-up and/or spalling.
    Type: Grant
    Filed: January 10, 2001
    Date of Patent: October 14, 2003
    Assignee: Stelco Inc.
    Inventor: Christian Albert Jager
  • Patent number: 6586117
    Abstract: A steel for forming a high strength steel sheet contains, in mass %, C: at most 0.04%, Si: at most 0.4%, Mn: 0.5-3.0%, P: at most 0.15%, S: at most 0.03%, Al: at most 0.50%, N: at most 0.01%, and Mo: 0.01-1.0%. Steel sheet formed from the steel is suitable for use as automotive panels.
    Type: Grant
    Filed: October 19, 2001
    Date of Patent: July 1, 2003
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Shigeki Nomura, Hiroyuki Nakagawa, Yoshiaki Nakazawa
  • Patent number: 6565991
    Abstract: A composite doctor blade comprises a steel support band configured with a width and thickness suitable for mounting in a blade holder, with tensile and yield strengths suitable for a selected doctoring application. A wear resistant strip of high speed steel is integrally joined to an edge of the support band. The wear resistant strip has tensile and yield strengths higher than those of the support band, and has a hardness of between about 55 to 75 Rc.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: May 20, 2003
    Assignee: Kadant Web Systems, Inc.
    Inventor: Bilal Mehmood
  • Patent number: 6537391
    Abstract: A steel has a tensile strength of 850 to 1700 MPa, a yield ratio of at most 80%, and a penetration border energy ratio of at least 2.0 relative to the penetration border energy of a reference steel JIS SS400 (corresponding to ASTM A36) of the same thickness. The steel can be produced by first effecting a heat treatment 1 on an unstable austenitic steel; then effecting, at least once, one or more or any combination of the heat treatment 1 and a heat treatment 2 on the steel; and then finally effecting the heat treatment 2 on the steel. Heat treatment 1 heats the unstable austenitic steel to at least the Ac3 transformation temperature and then water-cools the steel to a temperature below 350° C. Heat treatment 2 heats the steel to a temperature between Ac3 and Ac1 transformation temperatures and then water-cools the steel to a temperature below 350° C.
    Type: Grant
    Filed: June 12, 2001
    Date of Patent: March 25, 2003
    Assignees: Ishikawajima-Harima Jukogyo Kabushiki Kaisha, Kawasaki Steel Corporation
    Inventors: Kengo Ishige, Tadashi Shibue, Tsutomu Kakinouchi, Fumimaru Kawabata, Osamu Tanigawa, Kiyoshi Uchida, Junichi Kudou
  • Patent number: 6537397
    Abstract: In producing an Fe-based member, an Fe-based material comprising 0.6% by weight≦carbon (C)≦1.0% by weight silicon (Si)<2.2% by weight 0.9% by weight≦manganese (Mn)≦1.7% by weight 0.5% by weight≦nickel (Ni)≦1.5% by weight and the balance of iron (Fe) including inevitable impurities, is subjected, at a first step, to a thermal treatment at a heating temperature T1 set in a range of TS<T1<TL wherein TS represents a solidus temperature of the Fe-based material and TL represents a liquidus temperature, and under a cooling condition set at a quenching level. At a second step, the resulting Fe-based material is subjected to a thermal treatment at a heating temperature T2 set in a range of Te1<T2<Te2 wherein Te1 represents a eutectic transformation starting temperature and Te2 represents a eutectic transformation finishing temperature, and for a heating time t set in a range of 60 min≦t≦180 min.
    Type: Grant
    Filed: August 17, 1999
    Date of Patent: March 25, 2003
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventor: Takeshi Sugawara
  • Patent number: 6440584
    Abstract: A hot-dip galvanized steel sheet is produced by rough rolling a steel, finish rolling the rough rolled steel at a temperature of Ar3 point or more, coiling the finish rolled steel at a temperature of 700° C. or less, and hot-dip galvanizing the coiled steel at a pre-plating heating temperature of Ac1 to Ac3. A continuous hot-dip galvanizing operation is performed by soaking a pickled strip at a temperature of 750 to 850° C., cooling the soaked strip to a temperature range of 600° C. or less at a cooling rate of 1 to 50° C. per second, hot-dip galvanizing the cooled strip, and cooling the galvanized strip so that the residence time at 400 to 600° C. is within 200 seconds. The steel sheet has a structure consisting essentially of ferrite and martensite.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: August 27, 2002
    Assignee: NKK Corporation
    Inventors: Yasunobu Nagataki, Toshiaki Urabe, Fusato Kitano, Akio Kobayashi, Kunikazu Tomita, Shunsaku Node, Kozo Harada, Shogo Sato, Toru Inazumi
  • Patent number: 6423427
    Abstract: A composite doctor blade comprises a steel support band configured with a width and thickness suitable for mounting in a blade holder, with tensile and yield strengths suitable for a selected doctoring application. A wear resistant strip of high speed steel is integrally joined to an edge of the support band. The wear resistant strip has tensile and yield strengths higher than those of the support band, and has a hardness of between about 55 to 65 Rc.
    Type: Grant
    Filed: October 26, 2000
    Date of Patent: July 23, 2002
    Assignee: Kadant Web Systems, Inc.
    Inventor: Bilal Mehmood
  • Patent number: 6423426
    Abstract: A steel sheet having a composition comprising C: 0.05-0.20 mass %, Si: 0.3-1.8 mass %, Mn: 1.0-3.0 mass %, Fe of the balance and inevitable impurities is subjected to a primary step of primary heat treatment and subsequent rapid cooling to Ms point or lower, a secondary step of secondary heat treatment and subsequent rapid cooling, and a tertiary step of galvanizing treatment and rapid cooling, so as to turn the structure of the steel sheet into a composite structure of 20% or more by volume of tempered martensite, 2% or more by volume of retained austenite, ferrite and a low-temperature transformation phase. A galvanized layer is deposited on the surface of the steel sheet. It is preferred to cool the steel sheet to 300° C. at a cooling rate of 5 ° C./sec. or more after the galvanizing treatment. After the galvanizing treatment, alloying treatment may be conducted.
    Type: Grant
    Filed: March 5, 2001
    Date of Patent: July 23, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Takashi Kobayashi, Kei Sakata, Akio Shinohara
  • Patent number: 6355119
    Abstract: In a heat treatment method for producing boundary layer-hardened long products and flat products of unalloyed or low-alloy steel, the workpiece is cooled for producing a martensitic grain within a boundary layer of the workpiece by repeating several sequential cooling process steps. Each sequential cooling process step has a cooling phase, in which the workpiece is cooled to a temperature below a martensite starting temperature for martensitic conversion of only a portion of the boundary layer of the workpiece, and a temporal stress-relief phase for relieving stress within already formed martensitic grain areas and already formed martensite/austenite boundary areas. Subsequently, the workpiece is cooled at a cooling rate below a lower critical cooling rate for cooling the workpiece core.
    Type: Grant
    Filed: May 5, 2000
    Date of Patent: March 12, 2002
    Assignee: SMS Schloemann-Siemag Aktiengesellschaft
    Inventors: Andreas Peters, Meinert Meyer
  • Patent number: 6277214
    Abstract: The invention provides a process for the heat treatment of iron-based alloys, including irons and steels, such as carbon steels and low alloy steels, in a controlled oxidative environment, to modify the microstructure of the metal to obtain both improved mechanical properties and a protective surface oxide scale. In a first high-temperature treatment, a layer of wüstite (FeO) is formed on the surface of the material and austenite forms in the interior of the material. Rapid cooling follows the high temperature treatment so as to preserve the wüstite scale and to obtain at the same time an internal steel microstructure comprising martensite or bainite. In a second step of lower-temperature heat treatment, the scale is transformed so that it comprises an intermediate layer composed predominantly of wüstite (FeO), with a surface of predominantly magnetite (Fe3O4), while the mechanical properties of the material are tailored for specific applications.
    Type: Grant
    Filed: July 9, 1999
    Date of Patent: August 21, 2001
    Assignee: Powertech Labs Inc.
    Inventors: Ainul Akhtar, Gity Samadi
  • Patent number: 6251197
    Abstract: A rolling or sliding part is produced from a blank of steel material subjected to a heat treatment including carburization and thereby made to contain a spheroidal carbide precipitated and dispersed in a carburized layer matrix. The particle-to-particle distance of the spheroidal carbide is up to 15 &mgr;m in terms of the distance between the most proximate particles. The rolling or sliding part is suitable as antifriction bearing components, such bearing rings and rolling bodies, or as sliding bearing components, for use in soiled oil containing extraneous matter. The antifriction bearing comprising this part serves a lengthened rolling life in soiled oil and clean oil, and the sliding bearing incorporating the part is also given an extended life.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: June 26, 2001
    Assignee: Koyo Seiko Co., Ltd.
    Inventor: Kazutoshi Toda
  • Patent number: 6203634
    Abstract: A method for heat-treating a component of steel or cast iron, particularly a through hardening bearing steel component, involves heating the component to the austenitization temperature and holding the component at the austenitization temperature to achieve austenitization, rapidly quenching the component to approximately the martensite starting point (MS temperature) and holding the component at the bainite transformation temperature until partial bainite transformation occurs. After partial bainite transformation, the component is cooled down to and briefly held at room temperature, followed by short-cycle tempering.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: March 20, 2001
    Assignee: SKF GmbH
    Inventor: Johann Volkmuth
  • Patent number: 6190472
    Abstract: A method for soft annealing of high carbon steel, characterized by taking objects to be soft annealed directly from a hot forming step and cooling to below Al−20° C.; heating the objects to Al+20° C. or above, and then cooling the objects down to beneath the Al temperature of the steel quickly as in air, which step is performed at least once; heating the objects to Al+20° C. or above, cooling the objects down to about 740° C., and then cooling the objects down to about 690° C. at a cooling rate of 3.5° C./min. or lower; and finally cooling the objects down to ambient temperature.
    Type: Grant
    Filed: March 16, 1999
    Date of Patent: February 20, 2001
    Assignee: Ovako Steel AB
    Inventors: Thore Lund, Staffan Larsson, Patrik Ölund
  • Patent number: 6187118
    Abstract: A method of heat-treating a work piece of high-alloy steel by hardening involves relatively briefly annealing the work piece before hardening, followed by cooling the work piece. The brief annealing that is performed before the actual hardening and the ensuing cooling results in homogeneity of the material in the microscopic range. Following the annealing, the work piece is hardened, for instance by quenching in a salt bath, to achieve a super fine distribution of globular carbides in the microscopic structure with considerably reduced size as compared to the outset state. Also, the microscopic structure created by the method of the invention has improved toughness properties as well as increased microscopic structure stability to aging and leads to a longer service life.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: February 13, 2001
    Assignee: SKF GmbH
    Inventor: Wolfgang Nierlich
  • Patent number: 6174384
    Abstract: A medium-carbon steel is provided having a dispersed fine spherical graphite structure, having high mechanical strength, good processability, and good machinability, and having fine ZrC functioning as nucleation sites for graphite. The medium-carbon steel having a dispersed fine spherical graphite structure is manufactured by providing a composition containing 0.1 to 1.5% Si, 1.0% or less C, and 0.01 to 0.5% Zr. After the composition or a material of the composition (ingot) has been hot-rolled, or after the hot-rolled steel has been heat-treated at 750 to 1300° C. for 0.5 to 10 hours (solution heat treatment) after hot-rolling, or after the hot-rolled and heat-treated steel has further been water-quenched to deposit fine ZrC particles in the matrix, the steel is subjected to graphitization treatment by heat-treating at a temperature of 740° C. or below for 0.5 to 100 hours to grow graphite using ZrC as the nucleation site.
    Type: Grant
    Filed: August 25, 1999
    Date of Patent: January 16, 2001
    Assignee: Agency of Industrial Science and Technology
    Inventors: Katsunari Oikawa, Toshihiko Abe, Shin-Ichi Sumi
  • Patent number: 5900082
    Abstract: A method of making a heat treated steel casting comprising the steps of taking an "as-cast" steel casting comprising not more than 0.2% carbon, a total alloy content of less than about 4%, a carbon equivalent, as herein defined, lying in the range 0.45-0.7 and cooling the casting after performing the casting operation and then performing a heat treatment operation by re-heating the casting to a temperature above the AC.sub.3 temperature to homogenize the casting, then cooling the casting to an inter-critical temperature lying between the AC.sub.3 and AC.sub.1 temperature and then quenching to room temperature.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: May 4, 1999
    Assignee: NACO, Inc.
    Inventor: Paul Herbert Hewitt
  • Patent number: 5885382
    Abstract: In a method of continuously annealing steel strip comprising a heating step (A), a soaking step (B), a primary cooling step (C) including a rapid cooling step at least in a second half thereof, an overaging step (D), and a final cooling step (E), inert atmosphere gas containing H.sub.2 gas in the concentration of 30-60% is employed as cooling gas for use in the rapid cooling step, the blowoff temperature of the cooling gas is 30.degree.-150.degree. C., and the blowoff speed of the cooling gas is 100-150 m/sec. The primary cooling method in continuously annealing steel strip provides the primary cooling step (C) including the rapid cooling step which can be carried out with a high efficiency and a low cost.
    Type: Grant
    Filed: August 6, 1997
    Date of Patent: March 23, 1999
    Assignee: Nippon Steel Corporation
    Inventors: Koichi Sakurai, Tatsuru Shibuya, Hisamoto Wakabayashi, Kouichi Waki, Seiji Sugiyama, Kazunori Nagai
  • Patent number: 5533770
    Abstract: A steel for high-strength solid wheels and tires for railroad traction vehicles and cars that is more tenacious at the strengths typical of existing steels, and that is less likely to fracture even at constant braking. The steel has a specific ratio between major, alloying and companion elements, so that the steel is of high purity and uniformity. The heat treatment ensures a structure of excellent tenacity at high strength and of special endurance.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: July 9, 1996
    Assignee: MAN Gutehoffnungshutte Aktiengesellschaft
    Inventors: Horst Clausmeyer, Dieter Hoffmann, Wolfgang Weber
  • Patent number: 5342457
    Abstract: In a method for the production of a switch diamond for switch rails and double crossovers with a switch diamond point out of carbon steel and connector rails, the switch diamond point is rolled and submitted to heat treatment, by which the switch diamond point is transformed over its total cross-section into a fine pearlite texture, whereby subsequently the switch diamond point is tempered and at least in the area where the wheels roll over, a material removing treatment for the removal of the wheel zone texture different from the fine pearlite texture is put underneath and afterwards the switch diamond point is welded to connector rails, so that the production of a switch diamond is simplified and heat treatment in a conventional apparatus is made possible.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: August 30, 1994
    Assignee: Voest-Alpine Eisenbahnsysteme Gesellschaft m.b.H.
    Inventor: Johannes Blumauer
  • Patent number: 5221374
    Abstract: The agent in question is cobalt added in contents of between 0.05% and 2% to steels containing from 0.05% to 0.6% of carbon and less than 10% of alloying elements taken from silicon, manganese, nickel, chromium and molybdenum, to produce optionally normalized blocks, plates, bars or pieces of large size, with improved hydrogen cracking resistance and with improved weld-ability and suitability for thermal cutting. The invention also relates to a process for employing the agent and to the pieces thus obtained.
    Type: Grant
    Filed: December 16, 1991
    Date of Patent: June 22, 1993
    Assignee: Creusot Loire Industrie
    Inventors: Regis Blondeau, Jean Beguinot, Philippe Bourges, Lionel Coudreuse, Gilbert Primon, Jacques Charles
  • Patent number: 5125987
    Abstract: A method for direct patenting of a hot-rolled wire rod comprises the steps of: transporting a hot-rolled wire rod on a conveyer in a state that said wire rod is in a form of continuous series of loops; blasting mist to the surface of said wire rod at least from above and blasting air to the back side of the wire rod from below to cool the wire rod at a rate of 12.degree. C. to 50.degree. C./sec. down to 550.degree. C. to 400.degree. C. during the transportation, the mist provides 200 to 2400 l/min. water and has an air to water ratio of 200 Nm.sup.3 /m.sup.3 or less; and reheating the cooled wire rod at a rate of 3.degree. C./sec. or less, or cooling the cooled wire rod slowly at a rate of 2.degree. C./sec. or less during the transportation.
    Type: Grant
    Filed: July 30, 1991
    Date of Patent: June 30, 1992
    Assignee: Toa Steel Co., Ltd.
    Inventors: Toyoaki Eguchi, Noriyoshi Ohwada, Yutaka Sagae, Hirotada Ohsuzu, Katsumi Ito