A method includes preparing a steel slab in which contents of inhibitor components have been reduced, i.e. content of Al: 100 ppm or less, and contents of N, S and Se: 50 ppm, respectively; subjecting the steel slab to hot rolling and then either a single cold rolling process or two or more cold rolling processes interposing intermediate annealing(s) therebetween to obtain a steel sheet having the final sheet thickness; and subjecting the steel sheet to primary recrystallization annealing and then secondary recrystallization annealing. The primary recrystallization annealing includes heating the steel sheet to temperature equal to or higher than 700° C. at a heating rate of at least 150° C./s, cooling the steel sheet to a temperature range of 700° C. or lower, and then heating the steel sheet to soaking temperature at the average heating rate not exceeding 40° C./s in a subsequent heating zone.

Method for manufacturing grain-oriented electrical steel sheet

Disclosed is a process for the preparation of a grain oriented electrical steel sheet having a high flux density, which comprises hot-rolling a slab comprising 1.5 to 4.8% by weight of Si, 0.012 to 0.050 by weight of acid-soluble Al, up to 0.012% by weight of at least one member selected from S and Se, 0.0010 to 0.0120% by weight of N, Mn in an amount of up to 0.45% by weight which satisfies the requirement of Mn/(S + Se) ≧ 4.0 and 0.0005 to 0.0080% by weight of B, with the balance comprising Fe and unavoidable impurities, and option­ally, further comprising 0.0020 to 0.0120% by weight of Ti, performing cold rolling once or at least twice with intermediate annealing to obtain a final thickness, performing decarburization annealing in a wet hydrogen atmosphere, coating an annealing separator on the steel sheet surface, performing finish annealing for a secon­dary recrystallization and purification of the steel, and performing a nitriding treatment during the period of from the point of termination of final cold rolling to the point of initiation of secondary recrystalliza­tion at the finish annealing step. Furthermore, the above-mentioned slab is heated at a temperature lower than 1200°C before the hot rolling step, and even in the production of a thin product having a thickness of 0.10 to 0.23 mm, a high flux density can be realized.

Process for production of grain oriented electrical steel sheet having high flux density

A process is taught for improving the core loss of magnetic materials of the type having a plurality of magnetic domains and an insulative coating thereon. The insulative coating may be a mill glass, an applied coating, or both. The magnetic material is scanned by the beam of a laser across its rolling direction so as to subdivide the magnetic domains without damage to the insulative coating.

Laser treatment of electrical steel

Non-oriented silicon steel sheets having an excellent electromagnetic property is obtained by annealing a hot rolled steel sheet containing not moe than 0.02% of C, 0.5-3.5% of Si, 0.1-1.0% of Al, 0.1-1.0% of Mn, not more than 0.007% of S and 0.005-0.30% of Sb at a temperature of 700°-950° C., cold rolling the annealed sheet, and annealing the cold rolled sheet at a temperature of 750°-1,000° C.

Method of producing non-oriented silicon steel sheets having an excellent electromagnetic property

A grain-oriented magnetic steel sheet having linear grooves for magnetic domain refinement which have been formed in a surface of the steel sheet is produced in accordance with the present invention so that the proportion of linear grooves under which crystal grains having a deviation in orientation from the Goss orientation of 10o or more and having a grain diameter of 5 µm or more are present is regulated to 20% or less, and that the crystal grains formed by secondary recrystallization are regulated so as to have an average s angle of 2.0o or less and the crystal grains formed by secondary recrystallization which have a grain diameter of 10 mm or more are regulated so as to have an average width of s-angle fluctuations of 1-4o. Due to the formation of the linear grooves for magnetic domain refinement, a grain-oriented magnetic steel sheet reduced in iron loss can be obtained.

Grain oriented electrical steel sheet and method for manufacturing the same

Single-oriented electrical steel sheets having a high magnetic induction can be produced by hot rolling a silicon steel raw material containing less than 0.06% of C and less than 4% of Si, subjecting to annealing step and cold rolling step conveniently repeatedly to form a cold rolled steel sheet having a final gauge and subjecting to a decarburization annealing and a final annealing to develop secondary recrystallized grains having (110)[001] orientation, said silicon steel raw material being characterized in containing 0.005-0.200% of Sb and less than 0.10% of at least one of Se and S. Said final annealing for secondary recrystallization at a temperature of 800°-920°C gives a preferable result.

Yoshio Obata

Papers

Method for manufacturing single-oriented electrical steel sheets comprising antimony and having a high magnetic induction