Nippon Steel Corporation

Kajima Corporation

Nippon Steel Engineering Co., Ltd.

Akira Sakaida

Koji Yamasaki

Osamu Tanaka

Hisashi Mogi

Masahiro Fujikura

Tomoji Kumano

Hotaka Honma

Maremizu Ishibashi

Takeshi Saito

Tatsuhiko Sakai

Katsuro Kuroki

Katsuhiro Minamida

Naoya Hamada

Masato Mizokami

Hiroshi Sato

Tsutomu Haratani

Kenichi Yakashiro

Yoneo Yamada

Kimihiko Sugiyama

Hiromichi Koshiishi

Kentaro Chikuma

Chihiro Sakurai

Tsuyoshi Hamaya

Hiroshi Ishikawa

Masanori Karikomi

Masanori Niwa

Kunio Mori

Satoru Miura

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 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.

Grain-oriented electrical steel sheet for low-noise transformer

A grain-oriented electrical steel sheet with improved magnetic properties is achieved by a reduced 180&deg; 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;m . The magnetostriction with materials of 0.23 mm sheet thickness (&lgr;19 p-p compression) is no greater than 0.9&times;10 , and magnetostriction with materials of 0.27 mm sheet thickness (&lgr;19 p-p compression) is no greater than 1.3&times;10 .

Grain-oriented electrical steel sheets having excellent magnetic characteristics, its manufacturing method and its manufacturing device

Process for producing grain-oriented electrical steel sheet having

Disclosed is an annealing separator for production for grain-oriented electrical steel sheet, containing one or more compound selected from the following general formula;

Annealing separator having excellent reactivity for grain-oriented

A box annealed steel strip having small strains is produced by: pretreating a steel strip in such a manner that a side edge portion thereof is thermally treated under a different condition from another condition under which the remaining portion, including an opposite side edge, thereof is thermally treated, so as to cause the longitudinal length of the side edge portion to be different from that of the remaining portion; winding the pretreated steel strip under tension to form a coil in such a manner that greater tensile stresses are produced in the other one of the side edge portion and the remaining portion, which one has a longitudinal length smaller than that of the other one, than those produced in the other one; placing the coil on a base plate so that a side edge included in the portion having the greater stresses comes into contact with the base plate, and; box annealing the coil on the base plate in a box annealing furnace.

Process for box annealing a steel strip coil

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Tokyo, Japan

Akira Sakaida