Nippon Steel Corporation

Haruhiko Atsumi

Takashi Kataoka

Nobusato Morishige

Kazutoshi Takeda

Ichiro Tanaka

Yasuhiro Mayumi

Ryutaro Yamagata

Hirotoshi Tada

Tomoya Suenaga

Atsushi Suzuki

Hideyuki Hamamura

Yoshihiro Suwa

Kazumi Mizukami

Teruyuki Tamaki

Kazuhiko Fukutani

Toshiya Takechi

Masamitsu Kubota

Naoto Masumitsu

Shin Furutaku

Ryosuke Tomioka

Grain-oriented electrical steel sheet and its method of manufacture are provided. The method includes a process of heating to 1280° C. or more and hot rolling a slab containing, by mass %, Bi and a predetermined composition of constituents and having a balance of Fe and impurities to obtain hot rolled steel sheet. After hot rolling annealing, the hot rolled steel sheet is cold rolled one time or more with process annealing performed interposed so as to obtain cold rolled steel sheet, followed by a process of rapidly heating then decarburization annealing the steel sheet, a process of coating the surface of the cold rolled steel sheet after decarburization annealing with an annealing separator comprising sulfates or sulfides and having MgO as its main constituent, then performing finish annealing, a process of performing strictly controlled finish annealing, and a process of coating an insulating coating, then performing flattening annealing.

Method for manufacturing grain-oriented electrical steel sheet and grain-oriented electrical steel sheet

A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time Tat which Al shows a maximum emission intensity, an Al emission intensity F(T) at the T, a time Tat which Si shows a maximum emission intensity, and an Al emission intensity F(T) at the Tsatisfy 0.05≤F(T)/F(T)≤0.50 and 2.0≤(T−Ts)/(T−Ts)≤5.0.

Grain oriented electrical steel sheet

A method for manufacturing a grain-oriented electrical steel sheet according to an aspect of the present invention includes a step of obtaining a hot-rolled steel sheet by carrying out hot rolling on a slab containing a predetermined component composition with a remainder including Fe and impurities, a step of obtaining a hot-rolled annealed sheet by carrying out hot-rolled sheet annealing as necessary, a step of carrying out pickling to obtain a pickled sheet, a step of carrying out cold rolling to obtain a cold-rolled steel sheet, a step of carrying out primary recrystallization annealing, a step of applying an annealing separating agent including MgO to a surface and then carrying out final annealing to obtain a final-annealed sheet, and a step of applying an insulating coating and then carrying out flattening annealing.

A grain-oriented electrical steel sheet includes: a silicon steel sheet including Si and Mn; a glass film arranged on a surface of the silicon steel sheet; and an insulation coating arranged on a surface of the glass film, wherein the glass film includes a Mn-containing oxide.

Grain-oriented electrical steel sheet and method for producing thereof

A grain-oriented electrical steel sheet includes: a base steel sheet having a predetermined chemical composition; a glass coating provided on the surface of the base steel sheet; and a tension-applying insulation coating provided on the surface of the glass coating, in which linear thermal strains having, a predetermined angle (&#x3c6;) with respect to a transverse direction which is a direction orthogonal to a rolling direction are periodically formed on the surface of the tension-applying insulation coating at predetermined intervals along the rolling direction, a full width at half maximum F1 on the linear thermal strain and a full width at half maximum F2 at an intermediate position between the two linear thermal strains adjacent to each other satisfy 0.00&#x3c;(F1&#x2212;F2)/F2&#x2264;0.15, the width of the linear thermal strain is 10 &#x3bc;m or more and 300 &#x3bc;m or less, and in the base steel sheet, an orientation distribution angle &#x3b3; around a rolling direction axis of secondary recrystallization grains, an orientation distribution angle &#x3b1; around an axis parallel to a normal direction, and an orientation distribution angle &#x3b2; around an axis perpendicular to each of the RD axis and the ND axis in units of &#xb0; satisfy 1.0&#x2264;&#x3b3;&#x2264;8.0 and 0.0&#x2264;(&#x3b1;+&#x3b2;)&#x2264;10.0.

Grain-oriented electrical steel sheet and method for producing grain-oriented electrical steel sheet

A method for manufacturing a grain-oriented electrical steel sheet including a step of hot-rolling a slab containing a predetermined component composition with a remainder including Fe and an impurity to obtain a hot-rolled steel sheet, a step of, after carrying out hot-rolled steel sheet annealing on the hot-rolled steel sheet, carrying out cold rolling to obtain a cold-rolled steel sheet, a step of carrying out primary recrystallization annealing including a rapid temperature increase at an average temperature increase velocity V of 400&#xb0; C./s or more and imparting of a steel sheet tensile force S on the cold-rolled steel sheet, and a step of applying an annealing separating agent to a surface of the cold-rolled steel sheet after the primary recrystallization annealing and then carrying out flattening annealing.

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Tokyo, Japan

Haruhiko Atsumi