Kawasaki Steel Corporation

Yoshiaki Iida

Michiro Komatsubara

Isao Matoba

Ujihiro Nishiike

Katsuo Iwamoto

Yasuyuki Hayakawa

Mitsumasa Kurosawa

Takashi Obara

Tomomichi Goto

Yoshinori Kobayashi

Fumihiko Takeuchi

Masahiko Manabe

Hideo Kobayashi

Toshito Takamiya

Takahiro Kan

Bunjiro Fukuda

Toshio Sadayori

Yoh Shimizu

Hiromi Mitsunori

Masataka Yamada

Masayuki Sakaguchi

Kazumi Morita

Yoshinari Muro

A method of producing a non-oriented electromagnetic steel strip by subjecting a low-carbon steel slab to hot-rolling, cold rolling at a small reduction and first annealing. In order to improve magnetic flux density and surface appearance of the product, specific conditions are employed so as to coarsen the crystalline structure to obtain a controlled and moderate crystal grain size after the annealing. The slab is cold-rolled at a rolling reduction of about 5 to 15% and is subjected to first annealing by heating at a rate of about 3.degree. C./sec or higher and holding the strip for about 5 to 30 seconds at 850.degree. C. to the A.sub.3 transformation temperature of the steel, while controlling the crystal grain size to about 100 to 200 .mu.m after first annealing.

Method of producing non-oriented electromagnetic steel strip having

A method of producing a grain oriented silicon steel sheet is adapted to lower the iron loss. A silicon steel slab, containing about 2.0 to 4.0 weight % of Si and an inhibitor-forming amount of S, or Se, or both, is hot rolled. After the hot rolled steel sheet is annealed when necessary, the steel sheet is cold rolled into a cold rolled steel sheet having a final thickness by performing cold rolling either one time or a plurality of times with intermediate annealing therebetween, the cold rolled steel sheet then being subjected to decarburization, coating of the surface of the steel sheet with an annealing separation agent mainly comprising MgO, secondary recrystallization annealing, and purification annealing. In the cold rolling step, an oxide layer exists on the surface of the steel sheet. Specifically, in the cold rolling step, rolling oil is supplied only at the entrance of the rolling mill used, and an oxide layer having a thickness of about 0.05 to 5 .mu.m is generated. Or, an outer oxide layer of an oxide layer structure generated on the surface of the steel sheet after hot rolling or intermediate annealing, is removed, and an inner oxide layer of a thickness of about 0.05 to 5 .mu.m is maintained on the surface, the resultant steel sheet then being subjected to cold rolling.

Method of producing grain oriented silicon steel sheet having low iron

Method of producing grain oriented silicon steel sheets having improved

Process for producing grain oriented silicon steel sheets having

A grain-oriented silicon steel sheet having a low iron loss free from deterioration due to the stress-relief annealing, can be obtained by forming on its surface a forsterite film locally having regions, which have a thickness different from that of the remaining regions in the film, or locally having filmless regions which do not coat the steel sheet surface.

Grain-oriented silicon steel sheet having a low iron loss free from

The magnetic properties, particularly magnetic flux density of a grain oriented silicon steel sheet are considerably improved by continuously and/or stepwise forming regions, wherein a temperature difference of a secondary recrystallization starting temperature in widthwise direction and/or longitudinal direction of the steel sheet is within a range of 10.degree. C. to 200.degree. C., in the steel sheet at a stage before the secondary recrystallization annealing step.

Method of producing grain oriented silicon steel sheets having magnetic

A grain-oriented silicon steel sheet having a low iron loss, due to the subdividing effect of magnetic domain wall spacing, free from deterioration due to the stress-relief annealing, can be obtained by forming on its surface a forsterite film locally having regions, which have a thickness different from that of the remaining regions in the film, or locally having filmless regions which do not coat the steel sheet surface.

A grain-oriented silicon steel sheet having high magnetic induction and low iron loss can be obtained by adhering uniformly at least one member selected from the group consisting of elements of Ge, Sn, Pb, As, Bi and Zn and compounds containing these elements to the surfaces of a silicon steel sheet before or after the decarburization annealing in a method for producing grain-oriented silicon steel sheets. According to this method, a hot rolled steel sheet is subjected to at least one cold rolling, the finally cold rolled steel sheet is subjected to a decarburization annealing, and the decarburized steel sheet is applied with an annealing separator consisting mainly of MgO and then subjected to a final annealing, or by carrying out the adhesion treatment of element in combination with a preliminary annealing before the decarburization annealing in the above described method, or by using the annealing separator further containing Bi or a Bi-containing compound in the above described method.

Method for producing grain-oriented silicon steel sheets

A grain-oriented silicon steel sheet having excellent magnetic properties can be stably produced by adjusting properly the C content in a silicon steel to be used as a starting material depending upon the Si content in the steel, removing a proper amount of C from the steel during the course after the hot rolling and before the final cold rolling, and further carrying out the final cold rolling at a reduction rate of 40-80%.

Method of producing grain-oriented silicon steel sheets having excellent

A grain-oriented electrical steel sheet having a very high magnetic induction is obtained by developing secondary recrystallized grains at a specifically limited secondary recrystallization temperature in a cold rolled silicon steel sheet containing substantially no antimony and aluminum and having a specifically limited low nitrogen content.

Method for producing grain-oriented electrical steel sheets or strips

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Chiba, Japan

Yoshiaki Iida