Nippon Steel Corporation

Nittetsu Plant Designing Corporation

Nippon Steel Sumitomo Metal Corporation

Tomoji Kumano

Osamu Tanaka

Yoshiyuki Ushigami

Norikazu Fujii

Takeshi Kubota

Hiroyasu Fujii

Shuichi Nakamura

Koji Yamasaki

Yuji Kubo

Masayoshi Tanaka

Noriko Yamada

Hotaka Honma

Maremizu Ishibashi

Norihiro Yamamoto

Akira Sakaida

Kazutaka Higashine

Ryutaro Kawamata

Kazufumi Hanzawa

Chikara Kaido

Kenichi Murakami

Shinya Yano

Katsuro Kuroki

Hisashi Mogi

Takashi Morohoshi

Hidekuni Murakami

Tadashi Nakayama

Shingo Okada

Hiroaki Masui

Shozaburo Nakashima

Masafumi Zeze

Tsutomu Haratani

Yoshitaka Hiromae

Kenichi Yakashiro

Shinichi Kanao

Shota Morimoto

Chihiro Sakurai

Tsuyoshi Hamaya

Takashi Nagano

Ken-ichi Murakami

Hitoshi Yokouchi

Yoshifumi Ohata

Akio Oguri

Shyuichi Yamazaki

Yohichi Zaizen

Yuji Yoshimura

A grain-oriented electrical steel sheet having a metallographic structure after secondary-recrystallized annealing including matrix grains of Goss-oriented secondary recrystallized grains, wherein an existence frequency of Goss-oriented crystal grains having a major diameter of 5 mm or less in the matrix grains is 1.5 grains/cmor more and 8 grains/cmor less, and the magnetic flux density B8 is 1.88 T or more, and wherein deviation angles from a rolling direction of [001] direction of the Goss-oriented crystal grains having the major diameter of 5 mm or less are 7&#x2033; or less and 5&#xb0; or less, in terms of a simple or arithmetic average of &#x3b1; angle and &#x3b2; angle, respectively, wherein the &#x3b1; angle represents an angle formed by a longitudinal direction and a projection of the [001] on a specimen surface, and the &#x3b2; angle represents a tilt of the [001] out of the specimen surface.

Grain-oriented electrical steel sheet with excellent magnetic characteristics

A slab with a predetermined composition is heated at 1280&#xb0; C. to 1390&#xb0; C. to make a substance functioning as an inhibitor to be solid-solved (step S). Next, the slab is hot-rolled to obtain a steel strip (step S). The steel strip is annealed to form a primary inhibitor in the steel strip (step S). Next, the steel strip is cold-rolled once or more (step S). Next, the steel strip is annealed to perform decarburization and to cause primary recrystallization (step S). Next, nitriding treatment is performed on the steel strip in a mixed gas of hydrogen, nitrogen and ammonia under a state where the steel strip runs, to form a secondary inhibitor in the steel strip (step S). Next, the steel strip is annealed to induce secondary recrystallization (step S).

Manufacturing method of grain-oriented electrical steel sheet

A surface temperature of a slab is decreased down to 600&#xb0; C. or lower between start of continuous casting (step S) and start of slab reheating (step S). The surface temperature of the slab is held at 150&#xb0; C. or higher between the start of the continuous casting (step s) and the start of the slab reheating (step S). The surface temperature of the slab in the slab reheating (step S) is set to not lower than 1080&#xb0; C. and not higher than 1200&#xb0; C.

Method of treating steel for grain-oriented electrical steel sheet and method of manufacturing grain-oriented electrical steel sheet

In a production of grain-oriented electrical steel sheet that is heated at a temperature of not higher than 1350&#xb0; C., (a) the hot-rolled sheet is heated to a prescribed temperature of 1000&#xb0; C. to 1150&#xb0; C., and after recrystallization is annealed for a required time at a lower temperature of 850&#xb0; C. to 1100&#xb0; C., or (b) in the hot-rolled sheet annealing process decarburization is conducted to adjust the difference in the amount of carbon before and after decarburization to 0.002 to 0.02 mass %. In the temperature elevation process used in the decarburization annealing of the steel sheet, heating is conducted in the temperature range of 550&#xb0; C. to 720&#xb0; C. at a heating rate of at least 40&#xb0; C./s, preferably 75 to 125&#xb0; C./s, utilizing induction heating for the rapid heating used in the temperature elevation process in decarburization annealing.

Method of production of grain-oriented electrical steel sheet having a high magnetic flux density

Reheating a grain-oriented electrical steel sheet slab comprising predetermined components to 1280&#xb0; C. or more and a solid solution temperature of inhibitor substances or more, hot rolling, annealing, and cold rolling it, decarburization annealing it, nitriding it in a strip running state, coating an annealing separator, and finish annealing it during which making a precipitation ratio of N as AlN after hot rolling 20% or less, making a mean grain size of primary recrystallization 7 &#x3bc;m to less than 20 &#x3bc;m, and making a nitrogen increase &#x394;N in the nitridation within a range of Equation (1) and making nitrogen contents &#x3c3;Nand &#x3c3;N(front and back, mass %) of a 20% thickness portion of one surface of the steel strip (sheet) within a range of Equation (2):0.007&#x2212;([N]&#x2212;14/48&#xd7;[Ti])&#x2266;&#x394;N&#x2266;[solAl]&#xd7;14/27&#x2212;([N]&#x2212;14/48&#xd7;[Ti])+0.0025&#x2003;&#x2003;Equation (1)|&#x3c3;N1&#x2212;&#x3c3;N2|/&#x394;N&#x2266;0.35&#x2003;&#x2003;Equation (2).

Grain-oriented electrical steel sheet extremely excellent in magnetic properties and method of production of same

The invention provides a method of producing a grain-oriented electrical steel sheet of the complete solid solution nitrided type that is good in glass film formation and excellent in magnetic properties, which method comprises: C: 0.025 to 0.09%, hot-rolling the steel slab containing Si: 2.5 to 4.0% and acid-soluble Al into a hot-rolled steel strip; controlling the rate at which N contained in the hot-rolled steel strip is precipitated as AlN to a precipitation rate of 20% or less; conducting hot-rolled strip annealing and cold rolling conducting decarburization-annealing combined with primary recrystallization by during the former part of the process in an atmosphere whose PHO/PHis 0.30 to 0.70 and then during the latter part thereof in an atmosphere whose PHO/PHis 0.20 or less, thereby making the circular equivalent average grain diameter of the primary recrystallization grains 7 &#x3bc;m to less than 18 &#x3bc;m; nitriding the strip as it travels in a mixed gas of hydrogen, nitrogen and ammonia; controlling the steel strip oxygen concentration before secondary recrystallization annealing calculated based on strip thickness of 0.30 mm (oxygen content: So) to 450 ppm to 700 ppm inclusive; applying a coat of annealing separator; and then conducting secondary recrystallization annealing in an atmosphere that, while the temperature at the hottest coil outer periphery point is between room temperature and 950&#xb0; C., is controlled to a nitrogen atmosphere containing oxygen: 25 to 75% wherein the balance is hydrogen and PHO/PHis 0.01 to 0.15.

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

A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 &#x3bc;m, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400&#xb0; C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.

Core having superior end face insulation and method of treating core end faces to give insulation coating

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&plus;Mn&plus;Al&lE;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.

Low iron loss non-oriented electrical steel sheet excellent in workability and method for producing the same

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&deg; 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 (&deg; 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.

Method for producing a grain-oriented electrical steel sheet excellent in magnetic properties

Process for producing grain-oriented electrical steel sheet having

Process for producing non-oriented electrical steel sheet having high

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 method of producing non-oriented electrical steel sheet comprising the steps of preparing steel comprising, by weight, up to 2.5% silicon, up to 1.0% aluminum and up to 2.5% (Si+2Al), with the remainder being iron and unavoidable impurities, hot rolling and cold rolling the steel to a final thickness and following this by finish annealing, wherein the average cooling rate between Ar.sub.3 and Ar.sub.1 during cooling transformation (.gamma..fwdarw..alpha.) of the steel is controlled to be 50.degree. C./s or less.

Method of producing non-oriented electrical steel sheet having good

The present invention provides an annealing separator comprising from 0.05 to 2.0 parts by weight of antimony sulfate based on 100 parts by weight of magnesium oxide, and at least one chloride selected from the group consisting of Sb, Sr, Ti, and Zr chlorides in a chlorine amount of from 5 to 20% by weight based on 100% of the chloride and antimony sulfate, and occasionally comprises Ti oxide in an amount of from 0.5 to 10 parts. The annealing separator is applied on the decarburization annealed strip, and improves both the magnetic properties and properties of glass film, in the production of a grain-oriented electrical steel sheet.

Process for producing grain-oriented electrical steel sheet having both

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Tokyo, Japan

Tomoji Kumano