Working Patents (Class 148/111)
  • Patent number: 6666929
    Abstract: It has been found out that in the laser treatment for the control of the magnetic domain sizes in grain oriented electrical silicon steel sheets, by optimizing some essential parameters of the treatment such as specific radiation energy, the distance among the scribed traces, the scanning speed and the dwell time, a contemporaneous improvement of the magnetostriction, induction and core losses can be obtained.
    Type: Grant
    Filed: February 21, 2002
    Date of Patent: December 23, 2003
    Assignee: Acciai Speciali Terni, S.p.A.
    Inventor: Gabor Ban
  • Patent number: 6638368
    Abstract: The non-oriented electrical steel sheet having the following chemical composition: C: 0.01% or less, Si: 2.5% or less, Mn: 2% or less, Al: 1 to 5%, Si+Al+0.5×Mn: 2.5 to 5%, with a sheet thickness of 0.1 to 0.4 mm, an average grain diameter of 50 to 180 &mgr;m and a Vickers hardness of 130 to 210. The steel sheet is excellent in workability such as punchability and interlocking performance for forming it into cores for motors and also has a lower iron loss and higher magnetic flux density, and thus when used as a core in a motor, achieves the high a motor efficiency. The steel sheet is particularly suitable as a material for cores in inverter-controlled motors.
    Type: Grant
    Filed: November 2, 2001
    Date of Patent: October 28, 2003
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Ichiro Tanaka, Hiroyoshi Yashiki, Mitsuyo Maeda, Taisei Nakayama, Noriyuki Honjou, Shinsuke Mita
  • Publication number: 20030188805
    Abstract: The invention relates to a method for producing non-grain-oriented hot-rolled magnetic steel sheet in which from a raw material such as cast slabs, strip, roughed strip or thin slabs produced from a steel comprising (in weight %) C: 0.0001-0.05 %; Si: ≦1.5 %; Al: ≦0.5 %, wherein [% Si]+2[% Al]≦1.8; Mn: 0.1-1.2 %; if necessary up to a total of 1.5 % of alloying additions such as P, Sn, Sb, Zr, V, Ti, N, Ni, Co, Nb and/or B, with the remainder being iron and the usual impurities, in a finishing roll line at temperatures above the Ar1 temperature, a hot strip with a thickness ≦1.5 mm is rolled, wherein at least the last forming pass of hot rolling is carried out in the mixed region austenite/ferrite and wherein the total deformation &egr;H achieved during rolling in the mixed region austenite/ferrite is <35 %.
    Type: Application
    Filed: January 14, 2003
    Publication date: October 9, 2003
    Inventors: Karl Ernst Friedrich, Brigitte Hammer, Rudolf Kawalla, Olaf Fischer, J?uuml;rgen Schneider, Carl-Dieter Wuppermann
  • Publication number: 20030183304
    Abstract: A high flux density grain-oriented electrical steel sheet excellent in high magnetic field core loss property containing, in percentage by weight, not greater than 0.005% of C, 2.0-7.0% of Si, not greater than 0.2% of Mn, one or both of S and Se in a total amount of not greater than 0.005%, the balance being of Fe and unavoidable impurities, optionally containing, in percentage by weight, of not greater than 0.065% of Al, not greater than 0.005% of N and 0.003-0.3% each of one or more of Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr and Bi, the steel sheet having a grain orientation deviating from an ideal {110}<001>orientation by an average of not greater than 5°, having an average 180° magnetic domain width of not greater than 0.30 mm, preferably not greater than 0.26 mm or greater than 0.26 mm and not greater than 0.30 mm, and having an area ratio of magnetic domains of a width greater than 0.4 mm of greater than 3% and not greater than 20%.
    Type: Application
    Filed: March 28, 2003
    Publication date: October 2, 2003
    Applicant: Nippon Steel Corporation
    Inventors: Yousuke Kurosaki, Masahiro Fujikura
  • Patent number: 6613160
    Abstract: The present invention, in a method to produce a grain-oriented electrical steel sheet, proposes conditions for stable production by clarifying the causes by which secondary recrystallization is rendered unstable when primary recrystallization is controlled by raising the heating rate of decarburization annealing. The primary recrystallization structure is controlled by changing the heating rate and the oxide layer of a steel sheet is controlled by changing the conditions of soaking annealing in the decarburization annealing. The composition of the (Al, Si)N inhibitor is also controlled in the nitriding treatment thereafter.
    Type: Grant
    Filed: August 7, 2001
    Date of Patent: September 2, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Yoshiyuki Ushigami, Shuichi Nakamura, Kenichi Murakami, Hiroyasu Fujii, Norihiro Yamamoto
  • Publication number: 20030155040
    Abstract: In a method of producing a strip suitable for further processing to yield a (110)[001] grain oriented electrical steel from a thin strip such as a continuously cast thin strip the thin cast strip is processed to promote recrystallization from the surface layer of the strip (S=0) into the quarter thickness of the strip (S=0.2 to 0.3).
    Type: Application
    Filed: September 13, 2002
    Publication date: August 21, 2003
    Inventors: Jerry W. Schoen, Glenn S. Huppi
  • Publication number: 20030121566
    Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet.
    Type: Application
    Filed: June 6, 2002
    Publication date: July 3, 2003
    Applicant: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda
  • Patent number: 6582528
    Abstract: Method for producing non-grain-oriented electric sheet comprising: introducing steel input stock as a heated and prerolled slab into finishing rolls at a temperature of ≦1100° C. wherein the reheating temperature (TBR) corresponds to a reheating target temperature (TZBR) determined by the formula: TZBR(° C.)=1195° C.+12.716*(GSi+GAl) wherein TZBR(° C.)=target temperature of the reheated slab GSi=Si content in weight % GAl=Al content in weight % hot rolling to a thickness<3.5 mm at a final rolling temperature (TET)≧770° C. coiling at a temperature (THT) wherein THT(° C.)=154−1.8&agr;t+0.577 TET+111d/d0 wherein d0=reference thickness of the strip=3 mm d=actual thickness of the strip in mm t=time in seconds between the end of hot rolling and coiling &agr;=0.7/sec. to 1.3/sec. cooling factor pickling and cold rolling to a thickness of 0.2-1 mm.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: June 24, 2003
    Assignee: ThyssenKrupp Electrical Steel EBG GmbH
    Inventors: Thomas Böhm, Jürgen Schneider, Karl Telger, Carl-Dieter Wuppermann, Rudolf Kawalla, Karl Ernst Friedrich
  • Patent number: 6565674
    Abstract: A high flux density grain-oriented electrical steel sheet excellent in high magnetic field core loss property containing, in percentage by weight, not greater than 0.005% of C, 2.0-7.0% of Si, not greater than 0.2% of Mn, one or both of S and Se in a total amount of not greater than 0.005%, the balance being of Fe and unavoidable impurities, optionally containing, in percentage by weight, of not greater than 0.065% of Al, not greater than 0.005% of N and 0.003-0.3% each of one or more of Sb, Sn, Cu, Mo, Ge, B, Te, As, Cr and Bi, the steel sheet having a grain orientation deviating from an ideal {110}<001> orientation by an average of not greater than 5°, having an average 180° magnetic domain width of not greater than 0.30 mm, preferably not greater than 0.26 mm or greater than 0.26 mm and not greater than 0.30 mm, and having an area ratio of magnetic domains of a width greater than 0.4 mm of greater than 3% and not greater than 20%.
    Type: Grant
    Filed: May 30, 2000
    Date of Patent: May 20, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Yousuke Kurosaki, Masahiro Fujikura
  • Patent number: 6562473
    Abstract: Electrical steel sheets having superior magnetic properties, anti-noise properties, and workability, are ideal for use a compact iron core material in electric apparatuses, such as compact transformers, motors, and electric generators. A totally new electrical steel sheet and a manufacturing method therefor are proposed, in which the electrical steel sheet is not only most advantageous in magnetic properties but also advantageous from economic point of view. That is, the electrical steel sheet of the present invention is composed of from about 2.0 to 8.0 wt % Si, from about 0.005 to 3.0 wt % Mn, from about 0.0010 to 0.020 wt % Al, balance essentially iron. The magnetic flux density B50(L) in a rolling direction and the magnetic flux density B50(C) in the direction perpendicular thereto are 1.70 T or more, and the B50(L)/B50(C) is 1.005 to 1.100.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: May 13, 2003
    Assignee: Kawasaki Steel Corporation
    Inventors: Seiji Okabe, Yasuyuki Hayakawa, Takeshi Imamura, Mitsumasa Kurosawa
  • Patent number: 6562150
    Abstract: A steel sheet for heat shrink band of the present invention has anhysteretic magnetic permeability of 15,000 or higher at 0.35 Oe and yield stress of 24 kgf/mm2 or more. The steel sheet can be manufactured by a method comprising the steps of: hot rolling and/or cold rolling a steel containing 0.01 to 0.15% C by weight; annealing the rolled steel sheet at a temperature ranging from 650 to 900° C.; and temper rolling the annealed steel sheet at a rolling reduction rate of 1.5% or less. A CRT made of the steel sheet causes very little color deviation and practically no deformation of the panel surface.
    Type: Grant
    Filed: March 9, 2001
    Date of Patent: May 13, 2003
    Assignees: NKK Corporation, Sony Corporation
    Inventors: Tatsuhiko Hiratani, Hideki Matsuoka, Yasushi Tanaka, Reiko Sugihara
  • Patent number: 6558479
    Abstract: The object of the present invention is to provide a low iron loss and low noise grain-oriented electrical steel sheet for securing both low core loss and low noise of a transformer at the same time. The present invention relates to a grain-oriented electrical steel sheet containing Si: 1.0-4.0 wt % produced by controlling, with regard to &egr;O, which is defined as a 0-p value when a grain-oriented electrical steel sheet is magnetized up to a saturated magnetic flux density, and &egr;17, which is defined as the value obtained by subtracting a 0-p value at the magnetization magnetic flux density of 1.7 T from a 0-p value at a saturated magnetic flux density, &egr;OC and &egr;17L, which are absolute values deviated by forming a tension film and a forsterite film, and &egr;OL and &egr;17L, which are absolute values deviated by irradiating laser after the film formation, in adequate ranges respectively, and further controlling &lgr;17, which is a 0-p value at the magnetization magnetic flux density of 1.
    Type: Grant
    Filed: May 11, 2001
    Date of Patent: May 6, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Masahiro Fujikura, Satoshi Arai, Masato Mizokami, Hisashi Mogi, Takeshi Kubota
  • Patent number: 6524400
    Abstract: A process for the production of grain-oriented electric quality sheet by melting a silicon steel and casting the melt continuously into a strand having a thickness of 25-100 mm. During solidification the strand is cooled to a temperature above 700° C. and divided into thin slabs. The thin slabs then pass through an equalization furnace standing in line where they are reheated to a temperature ≦1170° C. and continuously rolled in a multi-stand hot rolling mill to give hot strip having a thickness of ≦3.0 mm. The first shaping pass is performed at a temperature in the rolling stock up to 1150° C. The reduction in thickness is at least 20%. The hot strip is cold rolled in one or more stages with recrystallizing intermediate annealing to a final thickness in the range of 0.15-0.50 mm. The cold strip is then annealed with recrystallization and decarburization, furnished with a predominantly MgO-containing annealing separator and given a final annealing for imprinting a Goss texture.
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: February 25, 2003
    Assignee: Thyssen Krupp Stahl AG
    Inventors: Hans Pircher, Rudolf Kawalla, Manfred Espenhahn, Andreas Böttcher, Klaus Günther, Hans Huneus, Carl-Dieter Wuppermann
  • Publication number: 20030034092
    Abstract: Manufacturing a grain-oriented electrical steel sheet, a secondary recrystallization step and a forsterite coating forming step are separated into first batch annealing for developing secondary recrystallization and second batch annealing for forming a forsterite coating, with continuous annealing performed between these two steps of batch annealing, to produce a grain-oriented electrical steel sheet that is superior in both magnetic characteristics and coating characteristics.
    Type: Application
    Filed: July 30, 2002
    Publication date: February 20, 2003
    Applicant: KAWASAKI STEEL CORPORATION
    Inventors: Minoru Takashima, Tetsuo Toge, Yasuyuki Hayakawa, Mitsumasa Kurosawa, Michiro Komatsubara
  • Patent number: 6503339
    Abstract: The invention relates to a method to produce non-grain-oriented magnetic steel sheet made of thin-slab or slab casting with low specific total loss and high polarisation and favourable mechanical properties. It is a characteristic of the invention that the steel slabs are hot rolled either directly from the casting heat or after a reheating to T≧900 ° C. and two or more metal forming passes are performed in the two-phase region austenite/ferrite in the course of finishing rolling.
    Type: Grant
    Filed: November 7, 2000
    Date of Patent: January 7, 2003
    Assignee: Thyssen Krupp Stahl AG
    Inventors: Hans Pircher, Rudolf Kawalla, Manfred Espenhahn, Brigitte Hammer, Klaus Peters, Jürgen Schneider, Carl-Dieter Wuppermann
  • Patent number: 6488784
    Abstract: By forming, after the annealing of the continuously cast body, a limited number of precipitates apt to the control of the grain growth, and utilising a cold rolling reduction ratio of at least 70%, it is possible to obtain in a subsequent step of continuous nitriding the direct formation of nitrides useful for the grain growth control and subsequently, still in a continuous treatment, to at least start the oriented secondary recrystallization.
    Type: Grant
    Filed: November 6, 2000
    Date of Patent: December 3, 2002
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Fortunati, Stefano Cicale′, Giuseppe Abbruzzese
  • Patent number: 6482271
    Abstract: The present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, which are improved by irradiating laser beams onto the positions paired on the both surfaces of the steel sheet and forming fine closure domains, characterized in that the width of the closure domains in the rolling direction is 0.3 mm or less and the deviation in the rolling direction between the positions of the paired closure domains on the both surfaces is equal to or smaller than the width of said closure domains in the rolling direction. Further, the present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, characterized in that the steel sheet has the marks of laser irradiation on its surface. Yet further, the present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, characterized in that the substrate steel is not exposed at the portions of laser irradiation on the surface of the steel sheet.
    Type: Grant
    Filed: April 24, 2001
    Date of Patent: November 19, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Tatsuhiko Sakai, Naoya Hamada
  • Patent number: 6479992
    Abstract: The present invention provides a leakage flux flaw detecting method in which a ferromagnetic substance such as a steel sheet or coil is magnetized by a plurality of magnetic fields with different intensity and magnetic flux leaking from the ferromagnetic substance having been magnetized is detected by a magnetic sensor, and output signals of the magnetic sensor after the detection of leakage flux are processed so that a signal caused by a flaw in the ferromagnetic substance is highlighted. Since this leakage flux flaw detecting method makes it possible to detect flaws with high accuracy, a scaled or descaled hot rolled steel sheet or coil in which the accurate flaw information such as location, density, size, and the like is known can be provided by applying this method to the manufacturing of hot rolled steel sheet or coil.
    Type: Grant
    Filed: January 7, 2002
    Date of Patent: November 12, 2002
    Assignee: NKK Corporation
    Inventors: Hiriharu Kato, Junichi Yotsuji, Akio Nagamune
  • Patent number: 6478892
    Abstract: The present invention provides a non-oriented electrical steel sheet having crystal grains of small diameter and excellent workability before stress relief annealing and having crystal grains of largely grown diameter and excellent iron loss property after stress relief annealing and a method for producing the same, and relates to a low iron loss non-oriented electrical steel sheet excellent in workability, containing, in weight %, 0.010% or less of C, 0.1 to 1.5% of Mn, 0.1 to 4% of Si, 0.1 to 4% of Al, wherein the latter three elements satisfy the formula Si+Mn+Al≦5.0%, and 0.0005 to 0.0200% of Mg, or further containing 0.005% or more of Ca, wherein the total amount of Mg and Ca is 0.0200% or less, or further containing 0.005% or more of REM, wherein the total amount of Mg and REM is 0.0200% or less, or further containing 0.005% or more of Ca and REM, wherein the total amount of Mg, Ca and REM is 0.0200% or less, and containing the remainder consisting of Fe and unavoidable impurities.
    Type: Grant
    Filed: April 6, 2001
    Date of Patent: November 12, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Ken-ichi Murakami, Takashi Morohoshi, Tomoji Kumano, Ryutaro Kawamata, Takeshi Kubota, Masafumi Zeze, Hidekuni Murakami, Shinichi Kanao
  • Publication number: 20020157734
    Abstract: A grain oriented electrical steel sheet comprises metal part containing Si: about 2.5 to about 5.0 mass % and Cr: about 0.05 to about 1.0 mass %, and an insulation coating formed on a surface of the metal part. A tension imparted to the metal part in the rolling direction by the insulation coating is not smaller than about 3.0 MPa. Magnetic flux density B8 satisfies a specific relation formula. A plurality of linear strains or grooves are formed in a surface of the steel sheet and linearly extended at an angle of not larger than about 45° (in each direction) relative to a direction perpendicular to a rolling direction such that an interval D of the linear strains or grooves satisfies a specific relation formula depending on the Cr content. A grain oriented electrical steel sheet is thereby obtained which has lower iron loss after domain refining treatment than conventional values.
    Type: Application
    Filed: January 24, 2002
    Publication date: October 31, 2002
    Inventors: Kunihiro Senda, Toshito Takamiya, Tadashi Nakanishi, Mitsumasa Kurosawa, Hiroaki Toda
  • Patent number: 6471787
    Abstract: A process for the production of oriented-grain electrical steel sheet with high magnetic characteristics, and more precisely a process in which the slab obtained from continuous casting is continuously nitrided by a reaction between aluminium and nitrogen is described. Amount, size and distribution of precipitates are controlled, enabling a high-temperature continuous heat treatment during which the primary-recrystallization and a high-temperature nitriding are realized.
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: October 29, 2002
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Cicale', Stefano Fortunati, Giuseppe Abbruzzese
  • Publication number: 20020153063
    Abstract: The present invention provides a non-oriented electrical steel sheet having ultra-high magnetic flux density and low core loss, characterized by: comprising a steel containing, in terms of wt %,
    Type: Application
    Filed: December 10, 2001
    Publication date: October 24, 2002
    Inventors: Ryutaro Kawamata, Takeshi Kubota
  • Publication number: 20020139444
    Abstract: The present invention provides a grain-oriented electrical steel sheet excellent in film characteristics and iron loss characteristics, a process for producing the same and a decarburization annealing facility used for the process.
    Type: Application
    Filed: March 27, 2002
    Publication date: October 3, 2002
    Applicant: Nippon Steel Corporation
    Inventors: Kenji Kosuge, Kishio Mochinaga, Eiichi Nanba, Nobuo Tachibana, Shinya Ishii, Naoki Yagi
  • Publication number: 20020129873
    Abstract: Ferritic stainless steel, compirsing the following composition by weight:
    Type: Application
    Filed: March 8, 2002
    Publication date: September 19, 2002
    Applicant: UGINE-SAVOIE IMPHY
    Inventors: Etienne Havette, Christophe Bourgin, Benoit Pollet, Jean Lamontanara
  • Patent number: 6451128
    Abstract: A method for manufacturing a high magnetic flux density grain oriented electrical steel sheet is disclosed. A silicon steel slab is heated and hot-rolled, and the steel sheet is annealed and cold-rolled and decarburized. An annealing separator is spread on the steel sheet, and a final high temperature annealing is carried out. The silicon steel contains in weight % 0.02-0.045% of C, 2.90-3.30% of Si, 0.05-0.30% of Mn, 0.005-0.019% of Al, 0.003-0.008% of N, 0.006% or less of S (the above being main ingredients), 0.001-0.012% of B, and a balance of Fe and unavoidable impurities; or the above main ingredients plus 0.30-0.70% of Cu, 0.03-0.07% of Ni, 0.03-0.07% of Cr, and a balance of Fe and unavoidable impurities; or the above main ingredients plus 0.001-0.012% of B, 0.30-0.70% of Cu, 0.03-0.07% of Ni, 0.03-0.07% of Cr, and a balance of Fe and unavoidable impurities.
    Type: Grant
    Filed: February 25, 1999
    Date of Patent: September 17, 2002
    Assignee: Pohang Iron & Steel Co., Ltd.
    Inventors: Chung San Lee, Chan Hye Han, Jong Soo Woo, Gyu Seung Choi, Jae Kwan Kim, Byung Deuk Hong, Kyu Seok Han
  • Patent number: 6444049
    Abstract: Manufacture by rolling silicon steel having a silicon content of 3 wt % or greater and by rolling thin sendust sheet is implemented by powder metallurgical fabrication using powder as the starting raw material, and the average crystal grain size of the sheet-form sintered body or quick-cooled steel sheet is made 300 pm or less, whereby intra-grain slip transformation occurs after slip transformation in the grain boundaries, wherefore cold rolling is rendered possible. In addition, a mixture powder wherein pure iron powder and Fe—Si powder are mixed together in a prescribed proportion is fabricated with a powder metallurgy technique, and an iron-rich phase is caused to remain in the sintered body, whereby cold rolling is possible using the plastic transformation of those crystal grains. Furthermore, when a minute amount of a non-magnetic metal element such as Ti, V, or Al, etc.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: September 3, 2002
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Osamu Yamashita, Ken Makita, Masao Noumi, Tsunekazu Saigo
  • Patent number: 6444050
    Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet. Transformers based upon the steel sheet have excellent magnetic characteristics (iron loss and magnetic flux density) together with strain resistance, and the steel sheet has good practical device characteristics (building factor) after being assembled into a transformer.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: September 3, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda
  • Patent number: 6444051
    Abstract: A method of making a grain-oriented electromagnetic steel sheet having a low iron loss and a high magnetic flux density, from a steel slab with 0.03 to 0.095 wt % carbon, about 1.5 to 7.0 wt % Si, about 0.03 to 2.50 wt % manganese, about 0.003 to 0.040 wt % sulfur and/or selenium, about 0.0010 to 0.0070 wt % borbon, about 30 to 120 wtppm nitrogen, about 0.015 wt % or less aluminum, and about 0.010 wt % or less vanadium by subjecting the steel slab to reheating, hot rolling, rapid cooling, cold rolling, primary recrystallization annealing, coating with an annealing separator, final annealing, secondary recrystallization, and coiling.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: September 3, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Kazuaki Tamura, Mitsumasa Kurosawa
  • Patent number: 6436199
    Abstract: Non-oriented magnetic steel sheets, which are mainly used as materials for iron cores for use in electric apparatuses, have a low iron loss and a high magnetic flux density at the same time. The non-oriented magnetic steel sheet comprises from about 1.5 to about 8.0 weight % Si, from about 0.005 to about 2.50 weight % Mn, and not more than about 50 ppm each of C, S, N, O, and B, in which a crystal orientation parameter <&Ggr;> is 0.200 or less. In addition, the average crystal grain diameter is preferably from about 50 to about 500 &mgr;m, and an areal ratio of crystal grains on a surface of the steel sheet is preferably 20% and less, in which crystal plane orientations of the crystal grains are within 15° from the <111> axis. In addition, the non-oriented magnetic steel sheet preferably contains small amounts of elements such as Al, Sb, Ni, Sn, Cu, P, and Cr. The manufacturing method for the non-oriented magnetic steel is also described.
    Type: Grant
    Filed: August 29, 2000
    Date of Patent: August 20, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Yasuyuki Hayakawa, Mitsumasa Kurosawa, Masaki Kawano, Michiro Komatsubara, Yuka Komori, Kazuaki Tamura
  • Patent number: 6432222
    Abstract: A method for producing a grain-oriented electrical steel sheet excellent in magnetic property, comprising the steps of; heating a slab containing a prescribed amount of Al to a temperature of 1,200° C. or higher, hot-rolling the slab into a hot-rolled strip, annealing the strip as required, cold-rolling it once or twice or more with intermediate annealing(s), and decarburization annealing the cold rolled sheet, and final box annealing after the application of an annealing separator to prevent strip sticking during the annealing, characterized by heating the slab to a temperature (slab heating temperature Ts (° C.)) higher than the complete solution temperature of substances having intensities as inhibitors and nitriding treating the decarburization annealed steel sheet before the commencement of secondary recrystallization during the final box annealing.
    Type: Grant
    Filed: June 4, 2001
    Date of Patent: August 13, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Yoshifumi Ohata, Tomoji Kumano, Norikazu Fujii, Hisashi Mogi, Hitoshi Yokouchi, Norihiro Yamamoto
  • Patent number: 6416591
    Abstract: A finish annealed non-oriented electromagnetic steel sheet includes about 0.01 wt % or less of C, greater than about 1.0 wt % and at most about 3.5 wt % of Si, at least about 0.6 wt % and at most about 3.0 wt % of Al, at least about 0.1 wt % and at most about 2.0 wt % of Mn, at least about 2 ppm and at most about 80 ppm of one or more rare earth metals (REM), a maximum content of Ti and Zr being about 15 ppm and 80 ppm, respectively, wherein oxygen on the surface layer of the steel sheet is 1.0 g/e2 or less. Since the non-oriented electromagnetic steel sheet has desirable mechanical properties resulting from the increased amounts of Si and Al, a high magnetic flux density can be maintained without sacrificing a punching property as well as very low iron loss can be obtained even after stress relief annealing.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: July 9, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Masaki Kawano, Yoshihiro Ozaki, Atsuhito Honda
  • Patent number: 6416592
    Abstract: Electromagnetic steel sheet having excellent magnetic properties and a texture gratly integrated in the {100}<001> orientation, and an uncomplicated and low cost production method; with about a 15 &mgr;&OHgr;·cm or more specific resistivity, about a 2.0 or more {100}<001> integration degree/{111}<uvw> integration degree and about a 10 &mgr;m to 500 &mgr;m grain diameter; when about 0.1 to 3.5% by weight of Si is present, the {100}<001> integration degree is about 10 or more; when about 0.2 to 1.2% by weight of P is present, the{100}<001> integration degree is about 3 or more; by applying a large reduction ratio to a steel slab in the vicinity of the final stage of hot rolling, with the hot rolling finishing temperature controlled at about 750 to 1150° C., hot rolled steel having a texture highly integrated in the {100}<001> orientation is economically produced.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: July 9, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Osamu Kondo, Akihiro Matsuzaki, Shigeaki Takajo
  • Patent number: 6406558
    Abstract: Manufacturing semiprocessed non-oriented magnetic steel sheets, which has superior workability in steps of assembling cores for motors or the like, in which improvement in productivity and higher accuracy of the products can be realized, by hot rolling a steel slab containing about 0.001 to 0.03 wt % C, about 0.1 to 1.0 wt % Si, about 0.01 to 1.0 wt % Al, about 0.05 to 1.0 wt % Mn, and about 0.001 to 0.15 wt % P, cold rolling the hot rolled sheet, continuous annealing the cold rolled sheet, and skin pass rolling the annealed sheet, wherein the average cooling rate in the continuous annealing process is about 10° C./second or more and skin pass rolling is performed at a reduction rate of about 0.5 to 5% within about 20 hours after continuous annealing.
    Type: Grant
    Filed: October 31, 2000
    Date of Patent: June 18, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Mitsumasa Kurosawa, Masaki Kawano, Michiro Komatsubara, Keiji Sakai, Toshiro Fujiyama
  • Patent number: 6406557
    Abstract: During the treatment of electrical steel, a careful combination of heat treatment of the slab with a specific primary recrystallization and nitriding treatment allows for control of the distribution, quantity and dimensions of precipitates in order to obtain a homogeneous precipitation of nitrogen compounds by direct reaction of the absorbed nitrogen with aluminum during the nitriding step.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: June 18, 2002
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Fortunati, Stefano Cicale′, Giuseppe Abbruzzese, Susanna Matera
  • Publication number: 20020066500
    Abstract: A finish annealed non-oriented electromagnetic steel sheet includes about 0.01 wt % or less of C, greater than about 1.0 wt % and at most about 3.5 wt % of Si, at least about 0.6 wt % and at most about 3.0 wt % of Al, at least about 0.1 wt % and at most about 2.0 wt % of Mn, at least about 2 ppm and at most about 80 ppm of one or more rare earth metals (REM), a maximum content of Ti and Zr being about 15 ppm and 80 ppm, respectively, wherein oxygen on the surface layer of the steel sheet is 1.0 g/m2 or less. Since the non-oriented electromagnetic steel sheet has desirable mechanical properties resulting from the increased amounts of Si and Al, a high magnetic flux density can be maintained without sacrificing a punching property as well as very low iron loss can be obtained even after stress relief annealing.
    Type: Application
    Filed: August 3, 2001
    Publication date: June 6, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Masaki Kawano, Yoshihiro Ozaki, Atsuhito Honda
  • Publication number: 20020059966
    Abstract: Electromagnetic steel sheet from a high-purity steel slab, composed essentially of Si 2.0 to 8.0 wt %, Mn 0.005 to 3.0 wt % and Al 0.0010 to 0.012 wt % with each of Se, S, N and O each not more than 30 ppm.
    Type: Application
    Filed: October 3, 2001
    Publication date: May 23, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Yasuyuki Hayakawa, Mitsumasa Kurosawa, Michiro Komatsubara
  • Publication number: 20020043299
    Abstract: The non-oriented electrical steel sheet having the following chemical composition: C: 0.01% or less, Si: 2.5% or less, Mn: 2% or less, Al: 1 to 5%, Si+Al+0.5×Mn: 2.5 to 5%, with a sheet thickness of 0.1 to 0.4 mm, an average grain diameter of 50 to 180 &mgr;m and a Vickers hardness of 130 to 210. The steel sheet is excellent in workability such as punchability and interlocking performance for forming it into cores for motors and also has a lower iron loss and higher magnetic flux density, and thus when used as a core in a motor, achieves the high a motor efficiency. The steel sheet is particularly suitable as a material for cores in inverter-controlled motors.
    Type: Application
    Filed: November 2, 2001
    Publication date: April 18, 2002
    Inventors: Ichiro Tanaka, Hiroyoshi Yashiki, Mitsuyo Maeda, Taisei Nakayama, Noriyuki Honjou, Shinsuke Mita
  • Patent number: 6368424
    Abstract: A grain-oriented electrical steel sheet with improved magnetic properties is achieved by a reduced 180° C. magnetic wall spacing with pulse laser light irradiation. The rolling direction width of the periodic closure domain generated by laser irradiation is no greater than 150 &mgr;m. The depth of the periodic closure domain in the direction of the steel sheet thickness is at least 30 &mgr;m. The product of the length of the periodic closure domain in the rolling direction width direction multiplied by the length of the depth of the periodic closure domain in the direction of the steel sheet thickness is at least 4500 &mgr;m2. The magnetostriction with materials of 0.23 mm sheet thickness (&lgr;19 p-p compression) is no greater than 0.9×10−6, and magnetostriction with materials of 0.27 mm sheet thickness (&lgr;19 p-p compression) is no greater than 1.3×10−6.
    Type: Grant
    Filed: August 20, 1998
    Date of Patent: April 9, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Tatsuhiko Sakai, Naoya Hamada, Katsuhiro Minamida, Kimihiko Sugiyama, Akira Sakaida, Hisashi Mogi
  • Patent number: 6364963
    Abstract: In a grain oriented electrical steel sheet used for cores of transformers and generators, a high alignment degree of grain orientations reduces iron loss, by precipitating very fine AlN or/and BN and providing strong inhibiting effect against the growth of the primary recrystallized grains, providing radically improved texture and grain structure in the steel.
    Type: Grant
    Filed: April 11, 2000
    Date of Patent: April 2, 2002
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda
  • Patent number: 6364962
    Abstract: Electromagnetic steel sheets which contain Cr in an amount of from about 1.5 to 20% by weight and Si in an amount of from about 2.5 to 10% by weight, while having a total amount of C and N of not larger than about 100 ppm by weight, and which has a specific resistivity of not smaller than about 60 &mgr;&OHgr;·cm.
    Type: Grant
    Filed: August 29, 2000
    Date of Patent: April 2, 2002
    Inventors: Shigeaki Takajo, Takako Yamashita, Akihiro Matsuzaki, Osamu Kondo
  • Patent number: 6361621
    Abstract: The production of grain-oriented electrical steel sheets is disclosed wherein grain growth in the steel is inhibited by a method comprising the regulation of the content of sulfur and manganese in the steel strp and the cold rolled strip is continuously nitrided at high temperature.
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: March 26, 2002
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Fortunati, Stefano Cicale', Giuseppe Abbruzzese
  • Patent number: 6361620
    Abstract: In the production of grain-oriented electrical steel strip, the grain growth inhibition is controlled by balancing the copper, aluminum and carbonium content in order to control the type and quantity of precipitated second phases and obtain optimum grain dimensions during the decarburization annealing. This is done by using a continuous high-temperature thermal treatment in which nitrogen is diffused into the steel strip and aluminum is directly precipitated as aluminum nitride which controls the grain orientation of the final product.
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: March 26, 2002
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Cicale′, Stefano Fortunati, Giuseppe Abbruzzese
  • Publication number: 20020033206
    Abstract: A process for the production of oriented-grain electrical steel sheet with high magnetic characteristics, and more precisely a process in which the slab obtained from continuous casting is continuously nitrided by a reaction between aluminium and nitrogen is described. Amount, size and distribution of precipitates are controlled, enabling a high-temperature continuous heat treatment during which the primarv-recrystallization and a high-temperature nitriding are realised.
    Type: Application
    Filed: June 22, 1999
    Publication date: March 21, 2002
    Inventors: STEFANO CICALE', STEFANO FORTUNATI, GIUSPEPPE ABBRUZZESE
  • Patent number: 6350355
    Abstract: The object of this invention was to create starting copper cathodes which prevent a memory effect during copper electrolysis, achieving a high production output of electrolytic copper and which can also be manufactured from directly shaped copper sheeting material in the form of a coil. A suitable method of producing starting cathodes for processing copper sheet produced by conventional methods. The proposed starting cathodes are made of milled copper sheets with a thickness of 0.3 to 1.2 mm, is soft annealed after milling and has a strength of 210 to 240 N/mm2. The copper sheet is cut to the length and width determined by the dimensions of the electrolysis bath and has a flat, fat-free, burless surface. Ear strips of copper sheet with a thickness of 0.3 to 0.6 mm are mounted on the suspension side.
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: February 26, 2002
    Assignee: Lamitref Industries N.V.
    Inventor: Leon Raphael Lucienne G. Cloostermans-Huwaert
  • Publication number: 20020011278
    Abstract: An electromagnetic steel sheet having a low iron loss and a high magnetic flux density, with silicon, nitrogen and an added element bismuth or germanium prior to secondary recrystallization, to accelerate precipitation of fine BN and silicon nitride, improving the texture of the primary recrystallized grains of the steel sheet immediately before subjecting it to secondary recrystallization annealing, and combining the primary recrystallization annealing, cold rolling and further the texture improving treatment. Addition of bismuth or germanium or both to the steel prior to secondary recrystallization is combined with primary recrystallization annealing and warm rolling in the presence of limited aluminum and vanadium impurities limited to 0.002 wt % Al or less and 0.010 wt % V or less.
    Type: Application
    Filed: August 9, 2001
    Publication date: January 31, 2002
    Applicant: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Kazuaki Tamura, Mitsumasa Kurosawa
  • Publication number: 20020007870
    Abstract: A method for producing a grain-oriented electrical steel sheet excellent in magnetic property, comprising the steps of; heating a slab containing a prescribed amount of Al to a temperature of 1,200° C. or higher, hot-rolling the slab into a hot-rolled strip, annealing the strip as required, cold-rolling it once or twice or more with intermediate annealing(s), and decarburization annealing the cold rolled sheet, and final box annealing after the application of an annealing separator to prevent strip sticking during the annealing, characterized by heating the slab to a temperature (slab heating temperature Ts(° C.)) higher than the complete solution temperature of substances having intensities as inhibitors and nitriding treating the decarburization annealed steel sheet before the commencement of secondary recrystallization during the final box annealing.
    Type: Application
    Filed: June 4, 2001
    Publication date: January 24, 2002
    Inventors: Yoshifumi Ohata, Tomoji Kumano, Norikazu Fujii, Hisashi Mogi, Hitoshi Yokouchi, Norihiro Yamamoto
  • Patent number: 6331215
    Abstract: A grain-oriented electromagnetic steel sheet is provided which has a low ratio of iron loss in a weaker magnetic field to that in a stronger magnetic field and has special advantage in EI cores and the like. Also provided is a process for producing that steel sheet. The grain-oriented electromagnetic steel sheet is characterized in that its crystal grains of important components are specified in terms of their proportions in number, and the contents of Al, Ti and B, with a forsterite film formed on a surface of the steel sheet. In the process a low-Al silicon slab is heated at below 1,250° C. before hot rolling and the hot-rolled sheet is annealed with a temperature rise in the range of from 5 to 25° C./sec and at a temperature of from about 800 to 1,000 for a period of time of shorter than about 100 seconds.
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: December 18, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Tetsuo Toge, Michiro Komatsubara, Atsuhito Honda, Kenichi Sadahiro, Kunihiro Senda
  • Patent number: 6325866
    Abstract: A process for the production of grain oriented silicon steel sheet which provides an optimization of the production of conventional, grain oriented silicon steel strips, by the use of an appropriate synergistic combination of the composition levels of some elements and appropriate treatments which result in the control of the presence and type of inhibitors, and by so doing, controlling the primary-recrystallization grain size.
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: December 4, 2001
    Assignee: Acciai Speciali Terni S.p.A.
    Inventors: Stefano Fortunati, Stefano Cicale′, Giuseppe Abbruzzese
  • Patent number: 6322639
    Abstract: A magnetic steel sheet used for an alternating current core, and having excellent magnetic properties in both a rolling direction, and the direction perpendicular thereto, and a method of producing the magnetic steel sheet. The magnetic steel sheet in a recrystallized cold-rolled condition is characterized in that the intensity ratio of {100}<001> orientation to random orientation is 2.0 or more, the intensity ratio of {011}<100> orientation to random orientation thereof is 2.0 to 10.0, and the intensity ratio of <001>//ND orientation to random orientation is preferably 2.0 or less. The method of producing a magnetic steel sheet includes hot-rolling a silicon steel slab so that the intensity ratio of (015)[100] orientation to random orientation of the recrystallized hot-rolled sheet is 3.0 or more.
    Type: Grant
    Filed: January 4, 2000
    Date of Patent: November 27, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Akihiro Matsuzaki, Osamu Kondo, Takako Yamashita, Shigeaki Takajo
  • Patent number: 6322635
    Abstract: Electromagnetic steel sheet from a high-purity steel slab, composed essentially of Si 2.0 to 8.0 wt %, Mn 0.005 to 3.0 wt % and Al 0.0010 to 0.012 wt % with each of Se, S, N and O each not more than 30 ppm.
    Type: Grant
    Filed: October 26, 1999
    Date of Patent: November 27, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Yasuyuki Hayakawa, Mitsumasa Kurosawa, Michiro Komatsubara