Jfe Steel Corporation

Kawasaki Steel Corporation

Kajima Corporation

Yoshiaki Iida

Yasuyuki Hayakawa

Mitsumasa Kurosawa

Toshio Sadayori

Michiro Komatsubara

Takeshi Imamura

Yukihiro Shingaki

Hiroi Yamaguchi

Minoru Takashima

Masanori Takenaka

Hiroshi Matsuda

Seiji Okabe

Takashi Terashima

Katsuo Iwamoto

Takahiro Kan

Yuiko Wakisaka

Hideyuki Takahashi

Makoto Watanabe

Yuiko Ehashi

Masataka Yamada

Takeshi Omura

Masaki Kawano

Ujihiro Nishiike

Toshito Takamiya

Kunihiro Senda

Shigehiro Takajo

Hirotaka Inoue

Kazuaki Tamura

Yuka Komori

Bunjiro Fukuda

Ryuichi Suehiro

Masayasu Ueno

Kazumichi Sashi

Takumi Umada

Hirotake Ishitobi

Shinichi Yoshikawa

Nobuyuki Matsui

Yoh Shimizu

Tetsuo Toge

Fumihiko Takeuchi

Shigeru Yoshida

Kazuo Okutsu

Hisashi Takamura

Toshio Sandayori

Tetsuya Oishi

Humihiko Takeuchi

Koji Hane

Mitsuaki Furuichi

Hideo Yamagami

Provided is a method for manufacturing a grain-oriented electrical steel sheet. A steel slab having a specific chemical composition is heated and hot rolled. A hot-rolled steel sheet thus obtained is subjected to hot band annealing to obtain a cold-rolled steel sheet, which is then subjected to primary recrystallization annealing to obtain a primary recrystallized steel sheet. An annealing separator is applied to the primary recrystallized steel sheet, which is then coiled. The coil is subjected to secondary recrystallization annealing to obtain a grain-oriented electrical steel sheet having an average value of a deviation angle (α+β)calculated from a deviation angle α from ideal Goss orientation around an ND rotation axis and a deviation angle β from ideal Goss orientation around a TD rotation axis of 4.5° or less, and an area ratio Rof crystal grains with β≤0.50° of 15% or less.

Method for manufacturing a grain-oriented electrical steel sheet

Provided is a grain-oriented electrical steel sheet that has excellent magnetic properties and can be manufactured by secondary recrystallization orientation control using coil annealing with high productivity. A grain-oriented electrical steel sheet comprises a specific chemical composition, wherein an average value of a deviation angle (&#x3b1;+&#x3b2;)calculated from a deviation angle &#x3b1; from ideal Goss orientation around an ND rotation axis and a deviation angle &#x3b2; from ideal Goss orientation around a TD rotation axis is 5.0&#xb0; or less, and an area ratio Rof crystal grains with &#x3b2;&#x2264;0.50&#xb0; is 20% or less.

Grain-oriented electrical steel sheet and method for manufacturing same

To improve and stabilize magnetic properties, a steel sheet is soaked in a temperature range of 1000&#xb0; C. or more and 1120&#xb0; C. or less for 200 sec or less and then soaked in a temperature range of 650&#xb0; C. or more and 1000&#xb0; C. or less for 200 sec or less in annealing before final cold rolling, and the amount of Al in precipitates after the annealing before the final cold rolling is limited to 50% or more of the total amount of Al contained in the steel slab.

Method of producing grain-oriented electrical steel sheet

To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones without requiring high-temperature slab heating, in the case of not performing intermediate annealing, the hot rolled steel sheet obtained by a predetermined step is subjected to hot band annealing, and, in a heating process in the hot band annealing, heating is performed at a heating rate of 10&#xb0; C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700&#xb0; C. or more and 950&#xb0; C. or less, and in the case of performing the intermediate annealing, in a heating process in final intermediate annealing, heating is performed at a heating rate of 10&#xb0; C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700&#xb0; C. or more and 950&#xb0; C. or less.

Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation, that enables generating glow discharge between positive electrodes and negative electrodes disposed in a nitriding zone and irradiating the generated plasma to a strip to perform appropriate nitriding.

Method for nitriding grain-oriented electrical steel sheet

Provided are: an oriented electromagnetic steel sheet with outstanding coating adhesion and magnetic properties after stress relief annealing; and a method for manufacturing the oriented electromagnetic steel sheet. The oriented electromagnetic steel sheet comprises: a steel sheet; a non-oxide ceramic coating disposed on the steel sheet and containing a non-oxide; and an insulating tensile coating disposed on the non-oxide ceramic coating and containing an oxide. The thickness of the non-oxide ceramic coating is 0.020-0.400 &#x3bc;m. The thickness of the insulating tensile coating is at least 1.0 &#x3bc;m. The chromium content on the steel plate side of the non-oxide ceramic coating is less than 25 atomic %, and the chromium content on the insulating tensile coating side of the non-oxide ceramic coating is at least 25 atomic %.

Oriented electromagnetic steel sheet and method for manufacturing oriented electromagnetic steel sheet

To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones, in hot band annealing of the hot rolled steel sheet obtained by a predetermined step, an average heating rate from ordinary temperature to 400&#xb0; C. is set to 50&#xb0; C./s or more, and a time to reach 900&#xb0; C. from 400&#xb0; C. is set to 100 sec or less.

The disclosure contains, in mass % or mass ppm: C: 0.005% or less, Si: 2.0% to 5.0%, Mn: 0.01% to 0.5%, sol.Al: 10 ppm or less, N: 15 ppm or less, S and Se: each 10 ppm or less, and three or more selected from Sn, Sb, Cr, P, Mo and B whose contents satisfy a relational expression of 0.16&#x2264;[% Sn]+[% Sb]+[% Cr]+2&#xd7;[% P]+[% Mo]+[% B]&#x2264;0.50, the balance being Fe and inevitable impurities, where a number of times of repeated bending in a bend test is 10 or more.

Grain-oriented electrical steel sheet and method for manufacturing the same

Disclosed is a method for manufacturing a grain-oriented electrical steel sheet using an inhibitor-less technique, in which cold rolling includes final cold rolling with a total cold rolling reduction being set to 85% or more and a rolling reduction per pass being set to 32% or more. The final cold rolling includes one or more passes and a final pass succeeding the one or more passes and uses work rolls having a surface roughness Ra of 0.25 &#x3bc;m or less in at least one of the one or more passes other than the final pass. According to this method, it is possible to stably manufacture a grain-oriented electrical steel sheet exhibiting excellent magnetic properties at low cost.

Method for manufacturing grain-oriented electrical steel sheet

Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation by immersing a strip in a molten salt bath after cold rolling and before secondary recrystallization annealing during a production process of a grain-oriented electrical steel sheet, to subject the strip to continuous nitriding to uniformly disperse inhibitor forming elements over the full length and full width of the strip.

Method and device for nitriding grain-oriented electrical steel sheet

Provided is an apparatus for continuously nitriding a strip continuously being fed after cold rolling and before secondary recrystallization annealing in a production line of a grain-oriented electrical steel sheet, comprising: a nitriding zone for nitriding the strip; a cooling zone for cooling the strip; and an optional heating zone provided upstream of the nitriding zone for heating the strip, wherein, the nitriding zone is provided with glow discharge electrodes, and by plasma nitriding the strip by glow discharge with the glow discharge electrodes functioning as positive electrodes and the strip functioning as a negative electrode, inhibitor forming elements are uniformly dispersed over the full length and full width of the strip and a grain-oriented electrical steel sheet with excellent magnetic properties with no variation is obtained.

Apparatus and method for nitriding grain-oriented electrical steel sheet

Provides is a method of producing a grain oriented electrical steel sheet by heating a steel slab having a predetermined composition, then subjecting the slab to hot rolling to obtain a hot rolled sheet, then optionally subjecting the hot rolled sheet to hot band annealing and subsequent cold rolling once, or twice or more with intermediate annealing performed therebetween to obtain a cold rolled sheet with final sheet thickness, then subjecting the cold rolled sheet to primary recrystallization annealing and subsequent secondary recrystallization annealing, in which the aging index AI of the steel sheet before final cold rolling is set to 70 MPa or less to effectively grow Goss-oriented grains to thereby obtain a grain-oriented electrical steel sheet with good magnetic properties, without the restriction of containing a relatively large amount of C.

Method of producing grain oriented electrical steel sheet

A method for producing a grain-oriented electrical steel sheets includes subjecting a steel slab to hot rolling to obtain a hot rolled sheet, the steel slab having a specific composition; then subjecting the hot rolled sheet to annealing and rolling to obtain a cold rolled sheet; then subjecting the cold rolled sheet to nitriding treatment with a nitrogen increase of 50 to 1000 ppm, during or after primary recrystallization annealing; then applying an annealing separator on the cold rolled sheet; and setting the staying time in a temperature range of 300 to 800&#xb0; C. in the secondary recrystallization annealing to 5 to 150 hours.

Production method for grain-oriented electrical steel sheet and primary recrystallized steel sheet for production of grain-oriented electrical steel sheet

In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition including C: 0.001&#x2dc;0.10 mass %, Si: 1.0&#x2dc;5.0 mass %, Mn: 0.01&#x2dc;0.5 mass %, Al: less than 0.0100 mass %, each of S, Se, O and N: not more than 0.0050 mass % and the remainder being Fe and inevitable impurities, subjecting the resulting hot rolled sheet to a single cold rolling or two or more cold rollings sandwiching an intermediate annealing therebetween to a final thickness, subjecting to a primary recrystallization annealing, applying an annealing separator thereto and then subjecting to a finish annealing, a zone of 550&#x2dc;700&#xb0; C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40&#x2dc;200&#xb0; C./s, while any temperature zone of 250&#x2dc;550&#xb0; C. is kept at a heating rate of not more than 10&#xb0; C./s for 1&#x2dc;10 seconds, whereby secondary recrystallized grains are refined to obtain a grain-oriented electrical steel sheet stably realizing a low iron loss.

Method for producing grain-oriented electrical steel sheet

Grain-oriented electrical steel sheets with good magnetic properties are industrially stably produced, by using as the material, a steel slab having a predetermined composition, wherein after cold rolling and before the start of secondary recrystallization annealing, the cold rolled sheet is subjected to nitriding treatment with nitrogen content of 50 mass ppm or more and 1000 mass ppm or less, and a total content of 0.2 mass % to 15 mass % of a sulfide and/or sulfate is contained in an annealing separator, and a staying time in the temperature range of 300&#xb0; C. to 800&#xb0; C. in the heating stage of secondary recrystallization annealing of 5 hours or more is secured to precipitate silicon nitride (SiN) and MnS, and using the silicon nitride in combination with MnS as inhibiting force for normal grain growth to significantly reduce variation of magnetic properties.

Production method for grain-oriented electrical steel sheet

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Tokyo, Japan

Yasuyuki Hayakawa