Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Yousuke Kurosaki

Takeshi Kubota

Masafumi Miyazaki

Shuichi Yamazaki

Takahide Shimazu

Masahiro Fujikura

Takeaki Wakisaka

Hideaki Yamamura

Nobuo Tachibana

Satoshi Arai

Kazutoshi Takeda

Wataru Ohashi

Kazumi Mizukami

Yoshihiro Arita

Kazuto Kawakami

Kenji Kosuge

Eiichi Nanba

Katsuyuki Yanagihara

Fumikazu Ando

Takashi Arai

Hiroshi Harada

Yutaka Matsumoto

Eiichiro Ishimaru

Hisashi Mogi

Takashi Sawai

Tomohiro Konno

Hotaka Honma

Isao Suichi

Norito Abe

Akihito Kiyose

Kiyokazu Ichimura

Kentaro Chikuma

Koichi Kirishiki

Ken-ichiro Miyamoto

Sadanobu Hirokami

Masayuki Yamashita

Kazuo Ohnuki

Wataru O-hashi

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 manufacturing method of a helical core for a rotating electrical machine includes: first step forming a yoke portion extending along one direction and tooth portions protruding toward a width direction of the yoke portion from a first side edge of the width direction, with respect to a belt-shaped metal plate extending along the one direction; second step forming a notch at a position between tooth portions of the yoke portion after the first step; and third step processing the belt-shaped metal plate into a helical shape by applying bending to the metal plate so that the belt-shaped metal plate is curved toward the width direction sequentially from a portion where the notch is formed after the second step, and in the third step, a distance between a position where the application of bending starts and the position where the notch is formed is limited to within a predetermined dimension.

Manufacturing method for helical core for rotating electrical machine and manufacturing device for helical core for rotating electrical machine

A non-oriented electrical steel sheet comprising, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, wherein Expression (1) is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]: [Ti]&#x2266;0.8&#xd7;[Bi]+0.002 . . . (1).

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 ().

In a non-oriented electrical steel sheet, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, and so on are contained. (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi].[Ti]&#x2266;0.8&#xd7;[Bi]+0.002&#x2003;&#x2003;(1)

A non-oriented electrical steel sheet contains Cr: 0.3 mass % to 5.3 mass %, Si: 1.5 mass % to 4 mass %, Al: 0.4 mass % to 3 mass %, and W: 0.0003 mass % to 0.01 mass %. A C content is 0.006 mass % or less, a Mn content is 1.5 mass % or less, a S content is 0.003 mass % or less, and a N content is 0.003 mass % or less, and the balance is composed of Fe and inevitable impurities.

Non-oriented electrical steel sheet

There is produced a molten steel containing, in mass %, Si: not less than 0.1% nor more than 7.0%, Mn: 0.1% or more, Al: not less than 0.2% nor more than 5.0%, Cr: not less than 0.1% nor more than 10%, and the like, and a balance composed of Fe and inevitable impurities. To the molten steel, REM: not less than 0.0005% nor more than 0.03% is added. The molten steel to which REM has been added is casted. A cast slab of non-oriented electrical steel is manufactured as above.

Cast slab of non-oriented electrical steel and manufacturing method thereof

A rapidly-solidified non-oriented electrical steel sheet having high magnetic flux density and low core loss is provided. The method of producing the non-oriented electrical steel sheet excellent in magnetic properties comprises casting a steel strip by using a traveling cooling roll surface(s) to solidify a steel melt of a prescribed chemical composition, which melt contains one or both of REM and Ca at a total content of 0.0020 to 0.01% and is cast in an atmosphere of Ar, He or a mixture thereof.

Method of producing non-oriented electrical steel sheet excellent in magnetic properties

The present invention is a grain-oriented electrical steel sheet characterized in that Bi is present at 0.01 to less than 1,000 ppm in terms of mass at the interface of the substrate steel and the primary film of the grain-oriented electrical steel sheet. The grain-oriented electrical steel sheet is produced by any of the processes of: before decarburization annealing, applying preliminary annealing for 1 to 20 sec. at 700&#xb0; C. or higher and controlling an atmosphere in the temperature range; controlling the maximum attaining temperature B (&#xb0; C.) before final cold rolling so that the maximum attaining temperature B may satisfy the expression, &#x2212;10&#xd7;ln(A)+1,100&#x2266;B&#x2266;10&#xd7;ln(A)+1,220, in accordance with a Bi content A (ppm) and at the same time heating the steel sheet cold rolled to the final thickness to 700&#xb0; C. or higher within 10 sec. or at a heating rate of 100&#xb0; C./sec. or more before decarburization annealing, or immediately thereafter applying preliminary annealing for 1 to 20 sec. at 700&#xb0; C. or higher; or controlling a TiOamount B added in relation to MgO of 100 as parts by weight and an MgO coating amount C (g/m) so that the expression, A&#x2266;B&#xd7;C&#x2266;400, may be satisfied in accordance with the Bi content A (ppm).

Ultra-high magnetic flux density grain-oriented electrical steel sheet excellent in iron loss at a high magnetic flux density and film properties and method for producing the same

Non-oriented electrical steel sheet superior in core loss characterized by containing, by mass %, C: 0.01% or less, Si: 0.1% to 7.0%, Al: 0.1% to 3.0%, Mn: 0.1% to 2.0%, N: 0.005% or less, Ti: 0.02% or less, REM: 0.05% or less, S: 0.005% or less, O: 0.005% or less, and a balance of iron and unavoidable impurities and having a mass % of S shown by [S], a mass % of O shown by [O], a mass % of REM shown by [REM], a mass % of Ti shown by [Ti], and a mass % of N shown by [N] satisfying [Formula 1] and [Formula 2]:[REM]&#xd7;[O]&#xd7;[S]&#x2267;1&#xd7;10&#x2003;&#x2003;[Formula 1]([REM]&#xd7;[O]&#xd7;[S])&#xf7;([Ti]&#xd7;[N])&#x2267;1&#xd7;10&#x2003;&#x2003;[Formula 2].

Non-oriented electrical steel superior in core loss

A nonoriented electrical steel sheet excellent in core loss comprising copper sulfides with a sphere-equivalent radius of 100 nm or less, wherein the number density of the copper sulfides is less than 1&#xd7;10[inclusions/mm]. Preferably, the percentage of the number of copper sulfides with a (major axis)/(minor axis) ratio of more than 2 per total number of copper sulfides is 30% or less. The steel preferably further comprises Cu of 0.5 mass % or less and REM of 0.0005% or more and 0.03% or less, wherein the following expression (1) or expressions (1) and (2) are met:[REM]&#xd7;[Cu]&#x2267;7.5&#xd7;10&#x2003;&#x2003;(1),([REM]&#x2212;0.003)&#xd7;[Cu]&#x2266;1.25&#xd7;10&#x2003;&#x2003;(2).

Nonoriented electrical steel sheet excellent in core loss

A non-oriented electrical steel sheet is characterized in that the number density of inclusions with an equivalent volume diameter of less than 100 nm contained in the steel sheet is 1&#xd7;10[/mm] or less, and that the steel sheet contains, by mass %, C: up to 0.01%, Si: 0.1% to 7.0%. Al: 0.1% to 3.0%. Mn: 0.1% to 2.0%, REM: 0.0003% to 0.05%. Ti: up to 0.02%. S: up to 0.005%. and N: up to 0.005%. the balance Fe and inevitable impurities and the mass % of Al represented by [Al] and the mass % of Ti represented by [Ti] satisfy the equation log([Ti]&#xd7;[N])&#x2212;1.19&#xd7;log([Al]&#xd7;[N])+1.84&#x3e;0 . . . (1).

Non-oriented electrical steel sheet excellent in core loss and manufacturing method thereof

A quench solidification method, wherein a steel cast strip having a mean grain size 50 &#x3bc;m or more is prepared and then the steel cast strip is rolled to produce a non-oriented electrical steel sheet having high magnetic flux density in both L and C directions. However the magnetic flux density reduces when the cold reduction rate exceeds 70%. To avoid this problem the non-oriented electrical steel sheet is manufactured with a ratio of at least 4 of the integrated intensity of the {100} plane for a given sample of steel to the integrated intensity of {100} plane for a 'random' sample in which crystal grains have random orientations; and a cold reduction rate of the cold-rolling is between 70% and 85%. The superheating degree of the molten steel can be 70&#xb0; C. or more.

Method for manufacturing non-oriented electrical steel sheet having high magnetic flux density

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%.

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Tokyo, Japan

Yousuke Kurosaki