With Working At Or Below 120c Or Unspecified Cold Working Patents (Class 148/603)
  • Publication number: 20040238081
    Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.
    Type: Application
    Filed: February 24, 2004
    Publication date: December 2, 2004
    Inventors: Naoki Yoshinaga, Nobuhiro Fujita, Manabu Takahashi, Koji Hashimoto, Shinya Sakamoto, Kaoru Kawasaki, Yasuhiro Shinohara, Takehide Senuma
  • Patent number: 6814817
    Abstract: A heat treated steel strap usable in a strapping machine has a tensile strength of at least about 170 KSI, and an elongation of at least about 6.5 percent. The steel strap is fabricated from a coiled steel reduced by cold rolling. The strap has a composition of 0.30 to 0.36 percent carbon, 0.90 to 1.25 percent manganese, and 0.75 to 1.10 percent silicon. The strap is heated to a temperature of about 815° C. to about 900° C. and quenched to a temperature of about 370° C. to about 510° C. The strap has a seal joint break strength of about 4350 pounds when the strap has a width of about one inch and a thickness of 0.030 inches. A method for forming the strap is also disclosed.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: November 9, 2004
    Assignee: Illinois Tool Works, Inc.
    Inventors: Jon E. Van Houten, Dennis A. Miller, Rainer Kammer, Erich Kruse
  • Publication number: 20040168753
    Abstract: A steel sheet containing 0.004 to 0.02% C, 1.0% or less Si, 0.7 to 3.0% Mn, 0.02 to 0.15% P, 0.02% or less S, 0.01 to 0.1% Al, 0.004% or less N, 0.2% or less Nb, by mass %, optionally Ti, Bi or at least one element selected from the group consisting of Cr Mo, Ni and Cu, and the balance being Fe; the Nb content satisfying a formula of (12/93)×Nb*/C≧1.0, wherein Nb*=Nb−(93/14)×N, and wherein C, N and Nb designate the content in mass % of carbon, nitrogen and niobium, respectively; and a yield strength and an average grain size of the ferritic grains which satisfy a formula of YP≦−120×d+1280, wherein YP designates yield strength in MPa, and d designates an average size of ferritic grains in &mgr;m.
    Type: Application
    Filed: March 2, 2004
    Publication date: September 2, 2004
    Applicant: NKK CORPORATION
    Inventors: Katsumi Nakajima, Takeshi Fujita, Toshiaki Urabe, Yuji Yamasaki, Fusato Kitano
  • Patent number: 6767417
    Abstract: The present invention relates to a steel sheet that consists essentially of 0.10 to 0.37% C, 1% or less Si, 2.5% or less Mn, 0.1% or less P, 0.03% or less S, 0.01 to 0.1% sol.Al, 0.0005 to 0.0050% N, 0.0003 to 0.0050% B, by mass, and balance of Fe, [14B/(10.8N)] being 0.5 or more, average particle size of precipitate BN being 0.1 &mgr;m or more, and grain size of prior austenite after the hardening treatment being 2 to 25 &mgr;m. The steel sheet according to the present invention allows an inexpensive hardening treatment method to be applied to improve the strength to a level required for the structural components and the functional components of automobiles, while providing excellent toughness after the hardening treatment.
    Type: Grant
    Filed: September 26, 2002
    Date of Patent: July 27, 2004
    Assignee: NKK Corporation
    Inventors: Takeshi Fujita, Kenichi Mitsuzuka, Nobuyuki Nakamura, Toshiaki Urabe, Katsutoshi Ito, Hideyuki Tsurumaru
  • Patent number: 6767415
    Abstract: A killed and vacuum-degassed very-low-carbon steel containing, by weight, between 0.10 and 0.35% manganese, less than 0.006% nitrogen, less than 0.025% phosphorus, less than 0.020% sulphur, less than 0.020% silicon, at most 0.08% of at least one of the elements copper, nickel and chromium, as well as aluminum. The steel is cast in the form of a slab, the slab is hot rolled in order to obtain a hot-rolled sheet, the hot-rolled sheet is coiled, the hot-rolled sheet is cold rolled in two rolling operations separated by a continuous annealing operation. The steel contains at most 0.006% carbon by weight and 0.010% aluminum and the hot-rolled sheet is coiled at a temperature below 620° C. Preferably, the steel is killed by mixing with a slag containing adjusted amounts of aluminum and of alumina.
    Type: Grant
    Filed: August 5, 1998
    Date of Patent: July 27, 2004
    Assignee: Sollac
    Inventors: Veronique Sardoy, Gilles Dahmen, Isabelle Poissonnet, Anne Blanchard, Pascal Choquet, Bernard Debiesme
  • Publication number: 20040123924
    Abstract: [Object] To provide a high carbon steel sheet having excellent hardenability and toughness, and low planar anisotropy of tensile properties affecting workability, and a method of producing the same.
    Type: Application
    Filed: September 19, 2003
    Publication date: July 1, 2004
    Applicant: NKK CORPORATION
    Inventors: Nobuyuki Nakamura, Takeshi Fujita, Katsutoshi Ito, Yasuyuki Takada
  • Publication number: 20040112483
    Abstract: The invention concerns a steel whereof the composition, expressed in wt. %, comprises: 0.03≦C<0.06; 0.50≦Mn≦1.10; 0.08≦Si≦0.20; 0.015≦Al≦0.070; N≦0.007; Ni≦0.040; Cu≦0.040; P≦0.035; S≦0.015; Mo≦0.008; Ti≦0.005; providing that it also comprises boron in an amount such that: 0.65≦B/N≦1.60, the rest of the composition consisting of iron and impurities resulting from preparation. The invention also concerns a method for making steel plates having said composition and the resulting plates.
    Type: Application
    Filed: January 14, 2004
    Publication date: June 17, 2004
    Inventors: Joel Marsal, Dominique Mescolini
  • Patent number: 6749696
    Abstract: The production of a cold-rolled strip or sheet of steel with good deforming properties, which is subjected to recrystallizing annealing and, if appropriate, a dressing operation after hot rolling, coiling and cold rolling and has a bake-hardening potential after a subsequent deformation and for a subsequent temperature treatment, succeeds because the recrystallizing annealing is carried out in a bell-type furnace while coiled and because the strip or sheet is subjected to cooling at a cooling rate of ≧1° C./s after the recrystallizing annealing from a temperature T of 200° C.≦T≦A1. It is consequently possible to obtain properties of bell-annealed steels and nevertheless attain a bake-hardening effect, in particular for C contents of ≧0.02%.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: June 15, 2004
    Assignee: Salzgitter AG
    Inventors: Klaus Freier, Volker Flaxa, Birgit Reichert
  • Publication number: 20040103962
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N, 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.
    Type: Application
    Filed: September 4, 2003
    Publication date: June 3, 2004
    Applicant: Kawasaki Steel Corporation, a corporation of Japan
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Patent number: 6743306
    Abstract: The steel sheet comprises: a ferritic phase having ferritic grains of 10 or more grain size number and ferritic grain boundaries; and at least one kind of Nb precipitates and Ti precipitates. The ferritic grain has a low density region with a low precipitate density in the vicinity of grain boundary. The low density region has a precipitate density of 60% or less to the precipitate density at center part of the ferritic grain. The steel sheet consists essentially of 0.002 to 0.02% C, 1% or less Si, 3% or less Mn, 0.1% or less P, 0.02% or less S, 0.01 to 0.1% sol.Al, 0.007% or less N, at least one element of 0.01 to 0.4% Nb and 0.005 to 0.3% Ti, by mass %, and the balance being Fe.
    Type: Grant
    Filed: January 11, 2002
    Date of Patent: June 1, 2004
    Assignee: NKK Corporation
    Inventors: Katsumi Nakajima, Takeshi Fujita, Toshiaki Urabe, Yuji Yamasaki, Fusato Kitano
  • Publication number: 20040055672
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N, 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.
    Type: Application
    Filed: September 4, 2003
    Publication date: March 25, 2004
    Applicant: Kawasaki Steel Corporation, a corporation of Japan
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Publication number: 20040050461
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N, 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.
    Type: Application
    Filed: September 4, 2003
    Publication date: March 18, 2004
    Applicant: Kawasaki Steel Corporation, a corporation of Japan
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Patent number: 6699334
    Abstract: This invention provides a steel sheet for a mask frame which maintains a tension-type color CRT shadow mask under tension. The steel sheet has a steel composition consisting essentially of, in mass %, C: 0.03-0.30%, Si: at most 0.30%, Mn: 0.05-1.5%, P: at most 0.05%, S: at most 0.02%, Mo: 0.02-0.50%, V: 0.02-0.20%, Al: at most 0.10%, N: 0.0040-0.0200%, optionally one or two or more of Cu: at most 1.0%, Ni: at most 1.0%, Cr: at most 2.0%, W: at most 1.0%, B: at most 0.003%, Ti: at most 0.030%, and Nb: at most 0.030%, and a balance of iron and unavoidable impurities, with Al≦(7.0)N, and having a metal structure in which the ferrite grain size is at most 15 micrometers and the ferrite volume ratio is at most 90%. The steel sheet is manufactured by hot rolling of a slab having the above-described steel composition under the conditions of a finishing temperature of 820-950° C. and a coiling temperature of 400-700° C.
    Type: Grant
    Filed: November 1, 2001
    Date of Patent: March 2, 2004
    Assignees: Sumitomo Metal Industries, Ltd., Matsushita Electric Industrial Co., Ltd.
    Inventors: Tatsuo Yoshii, Noriaki Nagao, Shinji Tsuge, Hideharu Ohmae
  • Patent number: 6695932
    Abstract: The present invention provides a cold-rolled sheet exhibiting superior strain-aging hardenability which is suitable for use in automobile bodies, and a method for manufacturing the same. In particular, a slab including, by mass, not more than 0.15% carbon, not more than 0.02% Al, and 0.0050% to 0.0250% nitrogen in which Si+Mn/5+10P is adjusted to less than 0.44 and the ratio N/Al is adjusted to not less than 0.3 is hot-rolled at a finish-rolling delivery temperature FDT of not less than 800° C., and then coiled at a temperature of not more than 650° C. Next, after cold-rolling, continuous-annealing at a temperature between the recrystallization temperature and 950° C., primary cooling for cooling to a temperature zone of not more than 500° C., and overaging in the temperature zone of 350° C. to 450° C. for a retention time of not more than 30 seconds are performed to prepare a steel sheet containing not less than 0.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: February 24, 2004
    Assignee: JFE Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka
  • Patent number: 6692584
    Abstract: The present invention provides a high tensile cold-rolled steel sheet having superior ductility, strain age-hardening characteristics, and crash resistance properties, and also provides a manufacturing method therefor. As a particular means, a thin cold-rolled steel sheet containing 0.05% to 0.30% of C, 0.4% to 2.0% of Si, 0.7% to 3.0% of Mn, 0.08% or less of P, 0.02% or less of Al, and 0.0050% to 0.0250% of N on a mass % basis is manufactured in which N/Al is 0.3 or more. This thin cold-rolled steel sheet is heated to a temperature between (an Ac1 transformation point) and (an Ac3 transformation point+50° C.), is cooled at a cooling rate of 5 to 150° C./second in the range of at least 600 to 500° C., and is held in the temperature range of 350 to 500° C. This steel sheet has superior ductility, strain age-hardening characteristics having a &Dgr;TS of 50 MPa or more, and crash resistance properties.
    Type: Grant
    Filed: December 12, 2001
    Date of Patent: February 17, 2004
    Assignee: JFE Steel Corporation
    Inventors: Kei Sakata, Akio Tosaka, Osamu Furukimi
  • Patent number: 6673170
    Abstract: Aluminum-killed medium carbon steel sheets, and the steel sheet stock prepared from it, is useful for manufacturing containers for a variety of food and industrial purposes. High mechanical strength is imparted to steel sheeting when the sheeting is processed through a continuous series of operations including cold-rolling and annealing. Annealing at a temperature maintained above the pearlitic transformation (Ac1) and rapid cooling yields steel sheet of high maximum rupture strength. Improved mechanical properties allows the steel sheet to be used in the manufacture of thin wall containers or containers of novel shape.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: January 6, 2004
    Assignee: Sollac
    Inventor: Mohamed Bouzekri
  • Patent number: 6673171
    Abstract: A method is provided for producing medium carbon steel sheet and strip with enhanced uniform elongation for deep drawing applications. In one embodiment, a steel slab containing carbon 0.30/0.70%, manganese 0.75/2.0%, silicon up to 1.0% max., total aluminum 0.020/0.10%, the balance iron and incidental impurities is hot rolled to strip at a finishing temperature within the range of 839° C. (1542° F.) to 773° C. (1424° F.) and spheroidize annealed at a temperature below the A1 temperature. In a second embodiment, a steel slab containing 0.40 minimum/0.70% maximum carbon, 0.50/1.50% manganese, up to 1.0% silicon, 0.020/0.10% total aluminum, the balance iron and incidental impurities is hot rolled, cold rolled and spheroidize annealed, with various combinations of manganese and silicon within the above ranges providing lower yield strength at levels of 60 ksi, 70 ksi, and 80 ksi with minimum 14% uniform elongation.
    Type: Grant
    Filed: August 16, 2002
    Date of Patent: January 6, 2004
    Assignee: United States Steel Corporation
    Inventors: Craig O. Hlady, Todd M. Osman
  • Patent number: 6645322
    Abstract: A method is provided for making carbon-steel blind slats and products thereof by slitting the carbon-steel sheet into pieces of desired width, trimming the edges, quenching, speedy cooling, tempering, and painting and baking. The blind product made by this method is merited in resilience, lifetime, easy maintenance, heat-resistance, fad-resistance, and is retrievable and reusable to conform to the environment protection conditions.
    Type: Grant
    Filed: May 25, 2001
    Date of Patent: November 11, 2003
    Inventor: Chin-Han Wang
  • Patent number: 6638380
    Abstract: A method for making a low carbon and low manganese cold rolled steel strip for deep-drawing whereby a steel strip hot rolled in the austenistic region coiled at the end of the high temperature hot rolling process (680° C.<T<750° C.) is subjected to a cold rolling process with a reduction rate between 65 and 80 %, and finally subjected to an annealing and overageing heat treatment. The method consists in heating the steel strip at a heating rate Vh ranging between 150° C./s and 1000° C. up to the annealing temperature Ta ranging between 650° C. and 750° C., and in maintaining it at said annealing temperature for a time interval between 1 and 20 seconds, then in cooling it at cooling rate Vc between 100° C./s and 500° C./s up to an overageing temperature Toa ranging between 150° C. and 450° C.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: October 28, 2003
    Assignee: Centre de Recherches Metallurgiques
    Inventors: Annick De Paepe, Jean Claude Herman, Stéphan Wilmotte
  • Patent number: 6635127
    Abstract: Steel strapping and a method of manufacturing steel strapping are disclosed. The steel strapping has the following composition in wt % and a microstructure including a matrix of recovery-annealed cold worked ferrite containing martensite and carbides dispersed through the matrix. C: up to 0.2 Mn: up to 2.0 Si: 0.2-0.4 Ti: 0.025-0.045 V: 0.05-0.07 Cr: up to 0.25 Ni: up to 0.30 Mo: up to 0.10 N: up to 0.005 Cu: up to 0.20 Al: up to 0.08 Nb: up to 0.005 P: up to 0.035 S: up to 0.020 Balance  iron and incidental impurities.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: October 21, 2003
    Assignee: Illinois Tool Works Inc.
    Inventors: Jeffery W Doonan, Peter Ivan Unicomb, Robert K Armstrong
  • Publication number: 20030188811
    Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.
    Type: Application
    Filed: January 13, 2003
    Publication date: October 9, 2003
    Applicant: Kawasaki Steel Corporation
    Inventors: Chikara Kami, Akio Tosaka, Kazunori Osawa, Shinjiro Kaneko, Takuya Yamazaki, Kaneharu Okuda, Takashi Ishikawa
  • Patent number: 6623691
    Abstract: The present invention describes an ultra-low carbon bake hardenable galvanized or galvannealed steel product, having a higher yield strength at the temperature of the molten zinc bath while maintaining a low yield strength and excellent bake hardening properties in a skinpassed condition, BH0 being higher than 35 MPa and BH2 higher than 40 MPa (GI) and BH0>20 MPa and BH2>30 MPa (GA), as well as having a superior paint appearance after stamping and painting. The content in the steel composition of the Ti is comprised between 3.42 N and 3.42 N+60 ppm for a fixed nitrogen content (N), and the Nb-content, comprised between 50 ppm and 100 ppm, is fixed so that no substantial precipitation of niobium carbides will occur during the process.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: September 23, 2003
    Assignee: Sidmar N.V.
    Inventors: Sven Vandeputte, Serge Claessens
  • Patent number: 6589369
    Abstract: A compound structure steel sheet excellent in burring workability made of a steel containing, by mass, 0.01 to 0.3% of C, 0.01 to 2% of Si, 0.05 to 3% of Mn, 0.1% or less of P, 0.01% or less of S, and 0.005 to 1% or Al, and having the microstructure being a compound structure having ferrite as the main phase and martensite or retained austenite mainly as the second phase, the quotient of the volume percentage of the second phase divided by the average grain size of the second phase being 3 or more and 12 or less, and the quotient of the average hardness of the second phase divided by the average hardness of the ferrite being 1.5 or more and 7 or less; or a compound structure steel sheet excellent in burring workability made of a steel containing, by mass, 0.01 to 0.3% of C, 0.01 to 2% of Si, 0.05 to 3% of Mn, 0.1% or less of P, 0.01% or less of S, and 0.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: July 8, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Tatsuo Yokoi, Manabu Takahashi, Hiroyuki Okada, Toshimitsu Aso
  • Patent number: 6582537
    Abstract: The present invention concerns a method for the production of cold-rolled bands or sheets from low-alloy steel with a maximum of 0.2% C, Al, Ti, V, Nb respectively and a maximum of 1% Si and Mn respectively, in addition to a portion of boron required for N binding (>0,78×N), the remainder being constituted by iron and unavoidable impurities, wherein said steel is cast after melting to slabs, thin slabs or a band, which are hot-rolled at a starting temperature above 1100° C. and at a final temperature below Ar3 and wherein the hot band is then drawn and cold-rolled at a temperature below 650° C., whereupon the cold band is annealed independently of the degree of cold-rolling at a low temperature that could possibly vary depending on the composition of the steel and ranging from 520 to 780° C. during a period of time that is sufficiently long to allow for complete recrystallization.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: June 24, 2003
    Assignee: Thyssen Krupp Stahl AG
    Inventors: Bernhard Engl, Klaus Dieter Horn, Klaus Dieter Schmidt
  • Publication number: 20030111144
    Abstract: The present invention provides a steel sheet having a chemical composition comprising 0.15% or less C, 2.0% or less Si, 3.0% or less Mn, P, S, Al and N in adjusted amounts, from 0.5 to 3.0% Cu, or one or more of Cr, Mo and W in a total amount of 2.0% or less, and having a composite structure comprising ferrite and martensite having an area ratio of 2% or more. The steel sheet is in the form of a high-strength hot-rolled steel sheet, a high-strength cold-rolled steel sheet, or a hot-dip galvanized steel sheet. There is thus available a steel sheet excellent in press-formability and in strain age hardening property as represented by a &Dgr;TS of 80 MPa or more.
    Type: Application
    Filed: December 31, 2001
    Publication date: June 19, 2003
    Inventors: Saiji Matsuoka, Tetsuo Shimizu, Kei Sakata, Osamu Furukimi
  • Publication number: 20030106622
    Abstract: A steel sheet composition contains appropriate amounts of C, Si, Mn, P, S, Al and N and 0.5 to 3.0% Cu. A composite structure of the steel sheet has a ferrite phase or a ferrite phase and a tempered martensite phase as a primary phase, and a secondary phase containing retained austenite in a volume ratio of not less than 1%. In place of the Cu, at least one of Mo, Cr, and W may be contained in a total amount of not more than 2.0%. This composition is useful in production of a high-ductility hot-rolled steel sheet, a high-ductility cold-rolled steel sheet and a high-ductility hot-dip galvanized steel sheet having excellent press formability and excellent stain age hardenability as represented by a &Dgr;TS of not less than 80 MPa, in which the tensile strength increases remarkably through a heat treatment at a relatively low temperature after press forming.
    Type: Application
    Filed: June 6, 2002
    Publication date: June 12, 2003
    Applicant: KAWASAKI STEEL CORPORATION
    Inventors: Saiji Matsuoka, Tetsuo Shimizu, Kei Sakata, Osamu Furukimi
  • Patent number: 6558486
    Abstract: Method of producing strip comprising continuously casting plain carbon steel into a strip of no more than 5 mm thickness and coiling the strip. The strip is subsequently uncoiled and cold rolled then annealed to produce a stress relieved microstructure therein. The cold rolling produces a cold reduction sufficient to increase the tensile strength of the strip to at least 680 MPa but is such that the total elongation to break off the strip after the annealing is in the range 8% to 12%. The cold rolling may produce a cold reduction of the strip thickness in the range 40% to 80%. The continuously cast strip may be optionally in-line hot rolled prior to coiling to produce an initial strip thickness in the range 40% to 60%.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: May 6, 2003
    Assignee: Castrip, LLC
    Inventors: Lazar Strezov, Kannappar Mukunthan
  • Patent number: 6554925
    Abstract: The method for manufacturing cold-rolled steel sheet comprises the steps of: rough-rolling a slab using a rough-rolling unit; finish-rolling the sheet bar using a continuous hot finishing-rolling mill; cooling the hot-rolled steel strip on a runout table; coiling thus cooled hot-rolled steel strip; and applying picking, cold-rolling the hot-rolled steel strip, and final annealing to the cold-rolled steel strip.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: April 29, 2003
    Assignee: NKK Corporation
    Inventors: Tadashi Inoue, Yasuhide Ishiguro, Yoichi Motoyashiki, Sadanori Imada, Toru Inazumi
  • Patent number: 6544354
    Abstract: The object of the present invention is to provide high-strength steel sheets exhibiting high impact energy absorption properties, as steel sheets to be used for shaping and working into such parts to front side members which absorb impact energy upon collision, as well as a method for their production.
    Type: Grant
    Filed: July 28, 1999
    Date of Patent: April 8, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Osamu Kawano, Junichi Wakita, Yuzo Takahashi, Hidesato Mabuchi, Manabu Takahashi, Akihiro Uenishi, Yukihisa Kuriyama, Riki Okamoto, Yasuharu Sakuma
  • Patent number: 6544355
    Abstract: A vitreous enamel steel sheet produced by a continuous casting, excellent in formability, bubbling and black spot resistance and adhesiveness, which comprises, in terms of mass %, 0.002% or less of C, 0.05 to 0.2% of Mn, 0.01% or less of Si, 0.004% or less of N, 0.015 to 0.05% of 0, less than 0.01% of P, 0.025% or less of S, 0.02 to 0.04% of Cu, 0.03 to 0.05% of Nb, and 0.03 to 0.07% of V, satisfying the inequality: 0.2>Mn (%)−2.0·O (%)+0.8·V (%)+0.5·Nb (%), and the balance consisting of Fe and unavoidable impurities, and a method for producing the same.
    Type: Grant
    Filed: March 12, 2001
    Date of Patent: April 8, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Satoshi Nishimura, Masayoshi Suehiro, Shiro Sanagi
  • Patent number: 6537394
    Abstract: A hot-dip galvanized high-strength steel sheet having superior workability and galvanizability containing: 0.01% to 0.20% by weight of C; 1.0% by weight or less of Si; more than 1.5% to 3.0% by weight of Mn; 0.10% by weight or less of P; 0.05% by weight or less of S; 0.10% by weight or less of Al; 0.010% by weight or less of N; 0.010% to 1.0% by weight in total of at least one element selected from the group consisting of Ti, Nb, and V; and the balance being Fe and incidental impurities; in which the steel sheet has the metal structure in which the areal rate of the ferrite phase is 50% or more, the ferrite phase has an average grain diameter of 10 &mgr;m or less, and the thickness of a band-like structure composed of the second phase satisfies the relationship Tb/T≦0.005, where Tb is the average thickness in the sheet thickness direction of the band-like structure and T is the thickness of the steel sheet, and a method for producing the same.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: March 25, 2003
    Assignee: Kawasaki Steel Corporation
    Inventors: Kazunori Osawa, Kei Sakata, Osamu Furukimi, Yoshitsugu Suzuki, Akio Shinohara
  • Patent number: 6533876
    Abstract: Process for producing a steel strip or sheet, in which liquid steel is cast in a continuous-casting machine to form a thin plate and, while making use of the casting heat, is fed through a furnace device, is roughed in a roughing stand to a pass-over thickness and is rerolled in a finishing rolling stand to form a steel strip or sheet of the desired final thickness, in which (a) to produce a ferritically rolled steel strip, the strip, the plate or a part thereof is fed without interruption at least from the furnace device, at speeds which essentially correspond to the speed of entry into the roughing stand and the following reductions in thickness, from the roughing stand to a processing device which is disposed downstream of the finishing rolling stand, the strip coming out of the roughing stand being cooled to a temperature at which the steel has an essentially ferritic structure; (b) to produce an austenitically rolled steel strip, the strip coming out of the roughing roll is brought to or held at a temper
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: March 18, 2003
    Assignee: Corus Staal
    Inventors: Marcus Cornelis Maria Cornelissen, Aldricus Maria Groot, Huibert Willem Den Hartog
  • Publication number: 20030047256
    Abstract: The present invention presents a high tensile strength cold rolled steel sheet having excellent formability, impact resistance and strain age hardening characteristics, and the production thereof. As a specific means, a slab having a composition which contains, by mass %, 0.15% or less of C, 0.02% or less of Al, and 0.0050 to 0.0250% of N at N/Al of 0.3 or higher, and has N in a solid solution state at 0.0010% or more, is first hot rolled at the finish rolling delivery-side temperature of 800° C. or above, and is subsequently coiled at the coiling temperature of 750° C. or below to prepare a hot rolled plate. Then, after cold rolling, the hot rolled plate is continuously cooled at a temperature from the recrystallization temperature to 900° C. at a holding time of 10 to 120 seconds, and is cooled by primary cooling in which the hot rolled plate is cooled to 500° C. or below at a cooling rate of 10 to 300° C.
    Type: Application
    Filed: October 24, 2001
    Publication date: March 13, 2003
    Inventors: Chikara Kami, Akio Tosaka, Kazunori Osawa, Shinjiro Kaneko, Takuya Yamazaki, Kaneharu Okuda, Takashi Ishikawa
  • Publication number: 20030015263
    Abstract: An object of the present invention is to provide a cold-rolled steel sheet and an alloyed hot-dip galvanized steel sheet in which tensile strength is effectively increased by press forming and heat treatment while maintaining excellent deep drawability in press forming. Specifically, a steel composition contains less than 0.01% of C, 0.005 to 1.0% of Si, 0.01 to 1.0% of Mn, 0.005 to 0.050% of Nb, 0.005 to 0.030% of Al, 0.005 to 0.040% of N, 0.0005 to 0.0015% of B, 0.05% or less of P, and 0.
    Type: Application
    Filed: January 18, 2002
    Publication date: January 23, 2003
    Inventors: Chikara Kami, Akio Tosaka, Takuya Yamazaki
  • Patent number: 6494969
    Abstract: The present invention relates to a very low C—Nb cold rolled steel sheet giving 340 to 440 MPa of tensile strength. For example, the cold rolled steel sheet consists essentially of 0.0040 to 0.01% C, not more than 0.05% Si, 0.1 to 1.0% Mn, 0.01 to 0.05% P, not more than 0.02% S, 0.01 to 0.1% sol.Al, not more than 0.004% N, 0.01 to 0.14% Nb, by weight, and balance of substantially Fe and inevitable impurities, and has not less than 0.21 of n value calculated from two points (1% and 10%) of nominal strain determined by the uniaxial tensile test, and relates to a method for manufacturing the cold rolled steel sheet. The present invention provides a high strength cold rolled steel sheet for automobile exterior panels having excellent combined formability, resistance to embrittlement during secondary operation, formability at welded portions, anti-burring performance, good surface appearance, and uniformity of material in a coil.
    Type: Grant
    Filed: August 3, 2000
    Date of Patent: December 17, 2002
    Assignee: NKK Corporation
    Inventors: Takeshi Fujita, Fusato Kitano, Yoshihiro Hosoya, Toru Inazumi, Yuji Yamasaki, Masaya Morita, Yasunobu Nagataki, Kohei Hasegawa, Hiroshi Matsuda, Moriaki Ono
  • Patent number: 6478899
    Abstract: A stainless steel band is continuously cast. The stainless steel band is descaled and cold rolled. The cold rolled band is annealed and descaled or bright annealed. The band is finish formed and finally coiled. The stainless steel band is not coiled after being continuously cast and before being finally coiled.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: November 12, 2002
    Assignee: Ugine S.A.
    Inventors: Hugues Legrand, Luc Vendeville, Jean Veyer, Francis Chassagne, Jean-Michel Damasse, Yann Breviere, Henri Giraud, Jean-Pierre Malingriaux, Michel Ternisien, Bernard Tetu, Bernard Vialatte
  • Publication number: 20020144755
    Abstract: Disclosed is the provision of a non-aging, highly anti-seed and anti-black-speck steel plate for enameling without relying upon decarbonization-denitrification annealing involving increased production cost, and without the addition of expensive elements, such as niobium and titanium involving increased alloying cost. This steel plate is produced by adopting a steel composition comprising, by weight, carbon: not more than 0.0018%, silicon: not more than 0.020%, manganese: 0.10 to 0.30%, phosphorus: 0.010 to 0.030%, sulfur: not more than 0.030%, aluminum: not more than 0.005%, nitrogen: 0.0008 to 0.0050%, boron: not more than 0.0050% and not less than 0.6 time the nitrogen content, and oxygen: 0.010 to 0.05%, and regulating the chemical composition of the steel and regulating mainly hot rolling conditions to regulate the form of nitrides.
    Type: Application
    Filed: February 21, 2002
    Publication date: October 10, 2002
    Inventors: Hidekuni Murakami, Satoshi Nishimura, Kazuhisa Kusumi, Shiroh Sanagi
  • Publication number: 20020088511
    Abstract: The present invention relates to a high carbon steel sheet having chemical composition specified by JIS G 4051 (Carbon steels for machine structural use), JIS G 4401 (Carbon tool steels) or JIS G 4802 (Cold-rolled steel strips for springs), wherein the ratio of number of carbides having a diameter of 0.6 &mgr;m less with respect to all the carbides is 80% or more, more than 50 carbides having a diameter of 1.5 &mgr;m or larger exist in 2500 &mgr;m2 of observation field area of electron microscope, and the &Dgr;r is more than −0.15 to less than 0.15. The high carbon steel sheet of the invention is excellent in hardenability and toughness, and formable with a high dimensional precision.
    Type: Application
    Filed: September 24, 2001
    Publication date: July 11, 2002
    Inventors: Nobuyuki Nakamura, Takeshi Fujita, Katsutoshi Ito, Yasuyuki Takada
  • Patent number: 6410163
    Abstract: The present invention provides a high strength thin excellent workability and galvanizability, having a composition comprising from 0.01 to 0.20 wt. % C, up to 1.0 wt. % Si, from 1.0 to 3.0 wt. % Mn, up to 0.10 wt. % P, up to 0.05 wt. % S, up to 0.10 wt. % Al, up to 0.010 wt. % N, up to 1.0 wt. % Cr, from 0.001 to 1.00 wt. % Mo, and the balance Fe and incidental impurities, wherein a band structure comprising a secondary phase has a thickness satisfying the relation Tb/T≦0.005 (where, Tb: average thickness of the band structure in the thickness direction of steel sheet; T: steel sheet thickness), and a manufacturing method thereof, and a manufacturing method of a high strength hot-dip galvanized steel sheet or a high strength galvannealed steel sheet applying hot-dip galvanizing or further galvannealing, and giving an excellent workability, a high tensile strength, and excellent galvanizability, coating adhesion and corrosion resistance.
    Type: Grant
    Filed: May 30, 2000
    Date of Patent: June 25, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Yoshitsugu Suzuki, Kazunori Osawa, Chiaki Kato, Yoichi Tobiyama, Kei Sakata, Osamu Furukimi, Akio Shinohara
  • Patent number: 6395108
    Abstract: A flat product made of multiphase steel and a method for preparing the steel includes hot rolling at a temperature at which the austenite phase is stable, then tempering to form a C and Mn-enriched phase in a matrix, followed by a heat treatment to form austenite islands and/or enriching in Mn the already formed austenite and cooling down to room temperature so as to obtain a final product with a ferrite matrix containing residual austenite, bainite and/or martensite islands.
    Type: Grant
    Filed: April 30, 2001
    Date of Patent: May 28, 2002
    Assignee: Recherche et Developpement du Groupe Cockerill Sambre
    Inventors: Klaus Eberle, Philippe Harlet, Pierre Cantinieaux
  • Patent number: 6375765
    Abstract: A thin ferritic steel sheet having an excellent shape fixability capable of being used for bending is provided, comprising: at least 0.027 to less than 0.05 mass % of C, 0.01 to 1.0 mass % of Si, 0.01 to 2.0 mass % of Mn, not more than 0.15 mass % of P, not more than 0.03 mass % of S, 0.01 to 0.1 mass % of Al, not more than 0.01 mass % of N, not more than 0.007 mass % of O, the balance being Fe and inevitable impurities, wherein a ratio of presence of {100} planes parallel with a face of the steel sheet to {111} planes is not less than 1.0, and TS×El, which represents a product of maximum tensile strength (TS) multiplied by rupture elongation (El) of the steel sheet, is at least 13,860 MPA %.
    Type: Grant
    Filed: March 27, 2000
    Date of Patent: April 23, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Manabu Takahashi, Osamu Akisue, Koji Kishida, Matsuo Usuda, Tohru Yoshida
  • Patent number: 6361624
    Abstract: A method of producing a fully stabilized extra low carbon porcelain enameling steel having excellent formability and fish scaling resistance as well as superior enamel adherence. The method includes hot rolling a slab to strip, the slab having a composition consisting essentially of in weight percent: 0.005 max. C, 0.35 max. Mn, 0.015 max. P, 0.015 max. S, 0.015 max. Si, 0.025 to 0.055 Al, 0.006 to 0.015 N, 0.03 to 0.06 Ti, 0.02 to 0.05 Cb, up to 0.03 Sb, the balance Fe and inevitable impurities. The hot rolled strip is cold rolled at least 65% and box annealed until a cold spot temperature within the range of 610 to 705 degrees C. is reached. The invention includes the product made according to the process.
    Type: Grant
    Filed: September 11, 2000
    Date of Patent: March 26, 2002
    Assignee: USX Corporation
    Inventor: George Franklin Altemus
  • Publication number: 20020005234
    Abstract: The present invention describes an ultra-low carbon bake hardenable galvanized or galvannealed steel product, having a higher yield strength at the temperature of the molten zinc bath while maintaining a low yield strength and excellent bake hardening properties in a skinpassed condition, BH0 being higher than 35 MPa and BH2 higher than 40 MPa (GI) and BH0>20 MPa and BH2>30 MPa (GA), as well as having a superior paint appearance after stamping and painting. The content in the steel composition of the Ti is comprised between 3,42 N and 3,42 N+60 ppm for a fixed nitrogen content (N), and the Nb-content, comprised between 50 ppm and 100 ppm, is fixed so that no substantial precipitation of niobium carbides will occur during the process.
    Type: Application
    Filed: December 22, 2000
    Publication date: January 17, 2002
    Inventors: Sven Vandeputte, Serge Claessens
  • Patent number: 6325874
    Abstract: A method of making high-strength steel structural members is disclosed by providing a flat-rolled blank of high-strength steel having a ferrite-pearlite microstructure and high-strength mechanical properties and cold forming the blank by rolling or the like to provide a structural member having a desired geometric cross-section while the mechanical strength of the structural member remains substantially the same or greater than the flat-rolled blank.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: December 4, 2001
    Assignee: Consolidated Metal Products, Inc.
    Inventor: Robert P. Wheeler, Jr.
  • Patent number: 6284069
    Abstract: The invention relates to a process for producing strips of homogenous structures and characteristics made of non-alloyed and low-alloyed steel by continuous hot rolling in several roll passes in the austenitic region and subsequently in the ferritic region, as well as coiling. The invention is characterised in that continuous-cast strip and/or strip rough rolled in the austenitic region, starting with a temperature T≧Ar3+30° C., with a total degree of deformation of eh≧30% is rolled in two or several roll passes in the austenitic region and in that the rolling stock is intensively cooled after every roll pass until the ferritic transformation has been completed, after which the rolling stock is end rolled to final thickness in the ferritic range in several passes with a total degree of deformation eh≧60%.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: September 4, 2001
    Assignee: Thyssen Krupp Stahl AG
    Inventors: Hans Pircher, Manfred Espenhahn, Rudolf Kawalla, Waldemar Wolpert
  • Patent number: 6264769
    Abstract: Apparatus for the production and heat treatment of coiled elongated metal product of relatively small cross section, such as rods, bars and wire-rod material, is described. The elements required for the conduct of a variety of heat treatments can be performed on coiled product in a substantially continuous manner through the use of a ring conveyor with which the coilers of various process lines and a heat treating furnace communicate. Methods for performing various heat treatments using the described apparatus are also disclosed.
    Type: Grant
    Filed: May 21, 1999
    Date of Patent: July 24, 2001
    Assignee: Danieli Technology, Inc.
    Inventor: Gianpietro Benedetti
  • Publication number: 20010000580
    Abstract: A steel sheet has composition consisting of 0.003-0.10 wt. % C, not more than 1.0 wt. % Si, 0.05-1.5 wt. % Mn, not more than 0.10 wt. % P, not more than 0.02 wt. % S, 1.5-8.0 wt. % Cr, 0.003-0.10 wt. % Al, at least one of 0.08-0.40 wt. % Ti, 0.08-0.40 wt. % Nb and 0.08-0.40 wt. % V, optionally at least one of Cu up to 2.0 wt. %, Ni up to 2.0 wt. %, 0.01-2.0 wt. % Mo, 0.01-2.0 wt. % W and 0.0003-0.0050 wt. % B and the balance being essentially Fe except inevitable impurities. The steel sheet is good of both a room-temperature strength and a high temperature strength. The new steel sheet is useful as a frame member of a color picture tube for stretching color selecting electrode elements, instead of an expensive ferritic stainless steel.
    Type: Application
    Filed: December 7, 2000
    Publication date: May 3, 2001
    Applicant: Nisshin Steel Co., and Sony Corporation
    Inventors: Yukio Katagiri, Akito Kawamoto, Seiichi Hamanaka, Nobuo Ozawa, Takahide Sanma
  • Patent number: 6221180
    Abstract: The invention provides a can steel sheet having satisfactory surface appearance and having workability, appearance property after working and high yield that can meet demands on complicated can forming, and a manufacturing process thereof. To be more specific, according to the invention, a slab having a composition containing, in weight %, C: more than 0.005% and equal to or less than 0.1%, Mn: 0.05-1.0% is subjected to hot-rolling at a finishing temperature of 800 to 1000° C., to coiling at 500 to 750° C., to cold-rolling, followed by continuous annealing at a recrystallization temperature or higher and 800° C. or lower, and then to box annealing at a temperature higher than 500° C. and equal to or lower than 600° C. for 1 hr or longer. The steel sheet has preferably a structure containing ferrite as a principle phase and having a mean grain diameter of 10 &mgr;m or less and further containing 0.1-1% by weight of pearlite grains each having a grain diameter of 0.5-3 &mgr;m.
    Type: Grant
    Filed: December 7, 1999
    Date of Patent: April 24, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Akio Tosaka, Masatoshi Aratani, Osamu Furukimi, Hideo Kuguminato, Makoto Aratani, Yuji Miki
  • Patent number: 6210501
    Abstract: When a hot-rolled steel strip 1 is rolled at a large rolling reduction by a cold-rolling mill 4, cracking and interlayer peeling occur in those mill-scales which can not keep up with the elongation of base steel so as to weaken the adhesiveness of the mill-scales to the base steel. When such a steel strip is then brushed, the threads of the brush penetrate into the cracks formed in the scale layer, whereby the mill-scales are removed from the steel strip. The rolling reduction R (%) is set to satisfy the formula of t×R≧150 in relation with the thickness t (&mgr;m) of the mill-scales. The mill-scales weakened in adhesiveness by the heavy-duty rolling are removed from the surface of the steep strip 1 by brush rolls 5 provided in the pass of the steel strip 1 between the cold-rolling mill 4 and the bridle rolls 5.
    Type: Grant
    Filed: August 21, 1997
    Date of Patent: April 3, 2001
    Assignee: Nisshin Steel Co., Ltd.
    Inventors: Tetsuhiko Okano, Toshinori Miki, Masaki Otsuka, Junya Hayakawa
  • Patent number: 6171412
    Abstract: Disclosed are bake-hardenable sheet steel with good anti-aging property and a method for producing it. While controlling its C, P, S and N contents, the chemical composition of the sheet steel is defined to comprise not larger than 1.0% of Si, not larger than 3.0% of Mn, from 0.01 to 0.20% of Al and from 0.001 to 0.2% of Ti, in terms of % by weight. The value A (=(AIQUENCH−AI)/AIQUENCH) of the sheet steel is defined to be not smaller than 0.4 and the value AIQUENCH thereof to be not smaller than 30; or the ratio of the mean misorientation, M (degree), to the mean grain size, G (&mgr;m), M/G, of the sheet steel is defined to be not smaller than 0.8. The steel may additionally contain from 0.001 to 0.2% of Nb and/or from 0.0001 to 0.0080% of B. While controlling its Si, Mn, S, Al and N contents, the chemical composition of a steel slab is defined to comprise from 0.005 to 0.02% of C, not larger than 0.05% of P and from 0.025 to 0.19% of Nb, with satisfying the condition of 0.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: January 9, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Saiji Matsuoka, Masahiko Morita, Osamu Furukimi, Takashi Obara, Tetsuya Kiyasu, Yoshio Yamazaki