Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Kajima Corporation

Nippon Steel Engineering Co., Ltd.

Masahiro Fujikura

Takeshi Kubota

Hisashi Mogi

Yoshiyuki Ushigami

Shuichi Yamazaki

Tesshu Murakawa

Masato Mizokami

Takeru Ichie

Shinichi Kanao

Makoto Atake

Kojiro Hori

Yousuke Kurosaki

Satoshi Arai

Yuichi Sato

Toshio Yamada

Shinichi Matsui

Takahide Shimazu

Akira Sakaida

Takeshi Saito

Hiroaki Sakamoto

Wataru Ohashi

Naruhiko Nomura

Hidekuni Murakami

Osamu Akisue

Yoshihiro Arita

Satoshi Yamashita

Toshio Mukai

Masao Yabumoto

Shigenobu Koga

Yoneo Yamada

Hiroshi Ishikawa

Kentaro Chikuma

Hideo Hagiwara

Fumio Hasebe

Hiromi Chida

Masanori Karikomi

Masanori Niwa

Satoru Miura

Shinishi Kanao

A non-oriented electrical steel sheet containing: in mass%, C: 0.005% or less; Si: 0.1% to 2.0%; Mn: 0.05% to 0.6%; P: 0.100% or less; and Al: 0.5% or less, in which 10 pieces/&#x3bc;mor less in number density of non-magnetic precipitate AlN having an average diameter of 10 nm to 200 nm are contained, and an average magnetic flux density B50 in a rolling direction and in a direction perpendicular to rolling is 1.75 T or more. This non-oriented electrical steel sheet can be manufactured by two methods of a method of performing hot rolling annealing at a temperature of 750&#xb0; C. to an Actransformation point and a method of setting a coil winding temperature to 780&#xb0; C. or higher and performing self annealing.

Non-oriented electrical steel sheet

A manufacturing method of a non-oriented electrical steel sheet includes: performing finish annealing of a cold-rolled steel strip; and forming a tension-applying type insulating film of not less than 1 g/mand not more than 6 g/mon a surface of the cold-rolled steel strip. The performing the finish annealing includes forming an oxide layer containing AlOor (Al, Cr)Oand having a thickness of not less than 0.01 &#x3bc;m and not more than 0.5 &#x3bc;m on the surface of the cold-rolled steel strip with setting a temperature of the cold-rolled steel strip to not lower than 800&#xb0; C. and not higher than 1100&#xb0; C. in an atmosphere where when the total content of Si and Al of the cold-rolled steel strip is represented as X (mass %), a partial pressure ratio of water vapor to hydrogen is equal to or less than 0.005&#xd7;X.

Non-oriented electrical steel sheet and manufacturing method thereof

A non-oriented electrical steel sheet containing: in mass %, C: 0.005% or less; Si: 0.1% to 2.0%; Mn: 0.05% to 0.6%; P: 0.100% or less; and Al: 0.5% or less, in which 10 pieces/&#x3bc;mor less in number density of non-magnetic precipitate AlN having an average diameter of 10 nm to 200 nm are contained, and an average magnetic flux density B50 in a rolling direction and in a direction perpendicular to rolling is 1.75 T or more. This non-oriented electrical steel sheet can be manufactured by two methods of a method of performing hot rolling annealing at a temperature of 750&#xb0; C. to an Ac1 transformation point and a method of setting a coil winding temperature to 780&#xb0; C. or higher and performing self annealing.

A value of a parameter Q represented by 'Q=([Ti]/48+[V]/51+[Zr]/91+[Nb]/93)/([C]/12)' is not less than 0.9 nor more than 1.1, when contents of Ti, V, Zr, Nb, and C (mass %) are represented as [Ti], [V], [Zr], [Nb], and [C] respectively. A matrix of a metal structure is a ferrite phase, and the metal structure does not contain a non-recrystallized structure. An average grain size of ferrite grains constituting the ferrite phase is not less than 30 &#x3bc;m nor more than 200 &#x3bc;m. A precipitate containing at least one selected from the group consisting of Ti, V, Zr, and Nb exists with a density of 1 particle/&#x3bc;mor more in the ferrite grain. An average grain size of the precipitate is not less than 0.002 &#x3bc;m nor more than 0.2 &#x3bc;m.

Non-oriented electrical steel sheet, manufacturing method thereof, laminate for motor iron core, and manufacturing method thereof

A steel having a predetermined composition is hot-rolled so as to form a steel strip, the steel strip is subjected to first cold-rolling, the steel strip is subjected to intermediate annealing, the steel strip is subjected to second cold-rolling, and the steel strip is subjected to finish annealing. A finish temperature in the hot-rolling is 900&#xb0; C. or less, annealing is not performed between the hot-rolling and the first cold-rolling, and a rolling reduction in the second cold-rolling is not less than 40% nor more than 85%.

Manufacturing method of non-oriented electrical steel sheet

When contents of Ti, V, Zr, Nb, and C (mass %) are represented as [Ti], [V], [Zr], [Nb], and [C] respectively, a value of a parameter Q represented by 'Q=([Ti]/48+[V]/51+[Zr]/91+[Nb]/93)/([C]/12)' is not less than 0.9 nor more than 1.1. A matrix of a metal structure is a ferrite phase, and the metal structure does not include a non-recrystallized structure. An average grain size of ferrite grains constituting the ferrite phase is not less than 10 &#x3bc;m nor more than 200 &#x3bc;m. A precipitate containing at least one selected from the group consisting of Ti, V, Zr, and Nb exists with a density of 10 &#x3bc;mor more in the ferrite grain. An average grain size of the precipitate is not less than 0.002 &#x3bc;m nor more than 0.2 &#x3bc;m.

Non-oriented electrical steel sheet, method of manufacturing the same, laminate for motor iron core, and method of manufacturing the same

A high-strength non-oriented electrical steel sheet contains: in mass %, C: 0.010% or less; Si: not less than 2.0% nor more than 4.0%; Mn: not less than 0.05% nor more than 0.50%; Al: not less than 0.2% nor more than 3.0%; N: 0.005% or less; S: not less than 0.005% nor more than 0.030%; and Cu: not less than 0.5% nor more than 3.0%, a balance being composed of Fe and inevitable impurities. An expression (1) is established where a Mn content is represented as [Mn] and a S content is represented as [S], and not less than 1.0&#xd7;10pieces nor more than 1.0&#xd7;10pieces of sulfide having a circle-equivalent diameter of not less than 0.1 &#x3bc;m nor more than 1.0 &#x3bc;m are contained per 1 mm10&#x2266;[Mn]/[S]&#x2266;50&#x2003;&#x2003;(1).

High-strength non-oriented electrical steel sheet

A non-oriented electrical steel sheet includes: a base iron (); and a tension applying type insulating film () of not less than 1 g/mnor more than 6 g/mon a surface of the base iron (). An oxide layer () containing at least one type of oxide selected from the group consisting of Si, Al, and Cr and having a thickness of not less than 0.01 &#x3bc;m nor more than 0.5 &#x3bc;m is formed on the surface of the base iron ().

A magnetic shield structure having openings, the structure comprising a plurality of similar magnetic blind bodies, each blind bodyhaving an imaginary blind core plane F and a plurality of magnetic material slatsbeing spaced from each other by a distance d required for magnetic shielding, each slatintersecting the blind core plane F at a longitudinal central axis C thereof, the longitudinal central axes of the slats are oriented substantially in parallel to each other on the blind core plane F. The blind bodiesare coupled in a row by serially coupling each slatin each blind bodyto a corresponding slatof adjacent blind bodythrough overlapping or abutting of slat terminal portions, whereby the blind core planes Fa, Fb of the blind bodiesare so coupled as to define a successive magnetic shield plane, and spaces d between adjacent slatsin each blind bodyform openings in the magnetic shield structure. Preferably, three or more magnetic blind bodiesare coupled in a row so as to form a closed magnetic path. The blind bodiesmay be stacked side by side in such a manner that the blind core plane Fa, Fb are parallel to each other and orientation of the slat central axes in each blind bodybeing selected so as to optimize attenuation of magnetic field across the magnetic shield structure.

Magnetic shield structure having openings and a magnetic material frame therefor

The present invention provides an electrical steel sheet core for a low-noise transformer capable of effectively lowering noise by suppressing vibration perpendicular to the surfaces of the steel sheets and reducing vibration, and relates to an electrical steel sheet for a low-noise transformer characterized by randomly inserting viscoelastic layers with both viscosity and elasticity into the gaps of the steel sheet lamination layers, and a low-noise transformer formed by using said electrical steel sheet.

Electrical steel sheet for low-noise transformer and low-noise transformer

The present invention provides a method for indirect-electrification-type continuous electrolytic etching of a metal strip suitable for producing a low-core-loss, grain-oriented silicon steel sheet not susceptible to the deterioration of core loss after stress-relief annealing, and an apparatus for the indirect-electrification-type continuous electrolytic etching. It is a method for indirect-electrification-type continuous electrolytic etching of a metal strip and an apparatus for the same for continuously forming grooves by indirect-electrification-type electrolytic etching on a metal strip on which an etching mask is formed in etching patterns on one or both surfaces, wherein: plural electrodes of an A series and a B series are arranged alternatively, at least in a pair, in said order in the travelling direction of the metal strip so that they face the surface to be etched of the metal strip on which the etching patterns are formed; the space between the metal strip and the group of the electrodes is filled with an electrolyte; and voltage is applied across the A series and B series electrodes.

Method for indirect-electrification-type continuous electrolytic etching of metal strip and apparatus for indirect-electrification-type continuous electrolytic etching

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 &#x3b5;, 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 &#x3b5;, 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, &#x3b5;and &#x3b5;, which are absolute values deviated by forming a tension film and a forsterite film, and &#x3b5;and &#x3b5;, which are absolute values deviated by irradiating laser after the film formation, in adequate ranges respectively, and further controlling &#x3bb;, which is a 0-p value at the magnetization magnetic flux density of 1.7 T, in the most appropriate range, when measuring a 0-p value of magnetostriction vibration in the rolling direction.

Low iron loss and low noise grain-oriented electrical steel sheet and a method for producing the same

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 &lcub;110&rcub;<001> orientation by an average of not greater than 5&deg;, having an average 180&deg; 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%.

High flux density grain-oriented electrical steel sheet excellent in high magnetic field core loss property and method of producing the same

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; , 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; , 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; and &egr; , which are absolute values deviated by forming a tension film and a forsterite film, and &egr; and &egr; , which are absolute values deviated by irradiating laser after the film formation, in adequate ranges respectively, and further controlling &lgr; , which is a 0-p value at the magnetization magnetic flux density of 1.7 T, in the most appropriate range, when measuring a 0-p value of magnetostriction vibration in the rolling direction.

The present invention provides a grain-oriented electrical steel sheet, for a low noise transformer, capable of reducing higher harmonics which are highly audible and lowering noise effectively, and relates to a grain-oriented electrical steel sheet for a low noise transformer, characterized by imposing a film tension of 0.5 to 6.0 MPa on the surface by coating or a method corresponding thereto, without forming a glass film on the grain-oriented electrical steel sheet or, if a glass film is formed, after removing the glass film by an arbitrary method.

Growing community of inventors

Tokyo, Japan

Masahiro Fujikura