Abstract: Manufacturing a grain-oriented electrical steel sheet, a secondary recrystallization step and a forsterite coating forming step are separated into first batch annealing for developing secondary recrystallization and second batch annealing for forming a forsterite coating, with continuous annealing performed between these two steps of batch annealing, to produce a grain-oriented electrical steel sheet that is superior in both magnetic characteristics and coating characteristics.

Abstract: The present invention relates to a grain-oriented magnetic steel sheet having extremely low iron loss, which is suitable for use as an iron core material for transformers and power generators, and to a method for producing the same. That is, in accordance with the present invention, a method for producing a grain-oriented magnetic steel sheet includes the step of forming a coating layer on a surface of the matrix of a steel sheet having a thickness of 0.27 mm or less by vapor deposition in a low oxidizing atmosphere with an oxygen partial pressure (Po2) of less than 0.1 atm and a total pressure of 0.1 atm or more. A grain-oriented magnetic steel sheet of the present invention having extremely low iron loss with a thickness of 0.27 mm or less includes a coating layer formed by vapor deposition on a matrix surface.

Abstract: A method of manufacturing a grain-oriented steel sheet including hot-rolling a slab prepared using molten steel containing, by mass %, C of not more than about 0.08%, Si of about 2.0 to about 8.0% and Mn of about 0.005 to about 3.0%; optionally annealing the hot-rolled steel sheet; performing cold rolling once, or twice or more with intermediate annealing therebetween; performing primary recrystallization annealing in a low- or non-oxidizative atmosphere and adjusting the C content in the steel sheet after primary recrystallization annealing to be held in the range of about 0.005 to about 0.025 mass %; performing secondary recrystallization annealing; decarburization annealing; and, preferably, performing additional high-temperature continuous or batch annealing. A grain-oriented electrical steel sheet having a sufficiently high magnetic flux density and a low iron loss can be advantageously obtained even when it is manufactured without using an inhibitor.

Abstract: Manufacturing a grain-oriented electrical steel sheet, a secondary recrystallization step and a forsterite coating forming step are separated into first batch annealing for developing secondary recrystallization and second batch annealing for forming a forsterite coating, with continuous annealing performed between these two steps of batch annealing, to produce a grain-oriented electrical steel sheet that is superior in both magnetic characteristics and coating characteristics.

Abstract: Grain oriented electrical steel sheet with a very low iron loss and a method for producing the same, wherein the surface of the iron substrate of the grain oriented electrical steel sheet is subjected to an enhancement treatment of crystal grain orientation or surface smoothing to a mean roughness of about 0.20 .mu.m or less, electroplating a chromium plating layer on the substrate with heterogeneous growth, and applying a tension coating film to the plating layer.

Abstract: In a non-oriented electromagnetic steel sheet including about 0.01 wt % or less of C, about 1.0 wt % or less of Si, Mn in a range of about 0.1 wt % to 1.5 wt %, Al in a range of about 0.2 wt % to 1.5 wt %; the steel sheet having a critical amount of about 2 to 80 ppm rare earth metal, and the quantities of Ti and Zr in the steel sheet being limited to about 15 ppm or less of Ti, and about 80 ppm or less of Zr. The sheet exhibits excellent magnetic characteristics, such as iron loss, even when punched and laminated sheets are stress relief annealed at a low temperature for a short period of time.

Abstract: The present invention relates to a semiprocessed nonoriented magnetic steel sheet which is used in iron cores of motors and transformers, finished to a final product by rolling having a reduction rate of 2 to 18% after final annealing by a manufacturer, and assures desired magnetic characteristics due to coarsening of crystal grains during strain-relief annealing after processing by a user. The excellent magnetic characteristics can be achieved by increasing lubrication during second cold rolling so as to satisfy the equation: e.sub.c .ltoreq.e.sub.s .ltoreq.1.18e.sub.c wherein e.sub.s represents a strain value at the surface layer of the steel sheet and e.sub.c represents a strain value at the central layer.

Abstract: Production of grain-oriented silicon steel sheet, in which the heating temperature of slabs is as low as that in common steels and good magnetic properties are maintained, without applying a nitriding process. The contents of Al, Se and S substantially satisfy formulae (1) and (2), and both or either of formulae (3) and (4):?Al (wt %)!+(5/9){?Se (wt %)!+2.47?S(wt %)!}.ltoreq.0.027 (1)?Se (wt %)!+2.47?S (wt %)!.ltoreq.0.025 (2)0.016.ltoreq.?Al (wt %)!+(5/9){?Se (wt %)!+2.47 ?S (wt %)!}(3)0.010.ltoreq.?Al (wt %)! (4)Annealing of the hot rolling sheet is applied at a temperature of about 800.degree. C. or more, and about 1000.degree. C. or below; preferably, cold rolling is applied at about 100.degree. C. or more, using a tandem mill.

Abstract: In a non-oriented electromagnetic steel sheet including about 0.01 wt % or less of C, about 1.0 wt % or less of Si, Mn in a range of about 0.1 wt % to 1.5 wt %, Al in a range of about 0.2 wt % to 1.5 wt %; the steel sheet having a critical amount of about 2 to 80 ppm rare earth metal, and the quantities of Ti and Zr in the steel sheet being limited to about 15 ppm or less of Ti, and about 80 ppm or less of Zr. The sheet exhibits excellent magnetic characteristics, such as iron loss, even when punched and laminated sheets are stress relief annealed at a low temperature for a short period of time.

Abstract: A non-oriented silicon steel sheet having a low core loss contains Si in an amount of about 2.5-5.0 wt % and S restricted to about 0.003 wt % or less and inclusions; the volume ratio of those inclusions having a particle size of about 4 .mu.m or higher to the total volume of inclusions is about 5-60%, and the volume ratio of inclusions having a particle size less than about 1 .mu.m to the total volume of inclusions is about 1-15%; when the sheet contains Mn in an amount of about 0.4-1.5%, and the volume ratio of particles less than 1 .mu.m is about 1-5%, the silicon steel sheet also has a low rotation core loss.The method of manufacturing comprises controlling the change of a cooling speed to about 5.degree. C./s.sup.2 or less in the cooling process of such steel sheet in a finish annealing.

Abstract: This invention relates to a non-oriented electromagnetic steel sheet with low leakage flux for a compact transformer and a method for making the same. After stress relief annealing, the magnetic permeability .mu..sub.C of the sheet in the direction transverse to the sheet rolling direction is.mu..sub.C .gtoreq.about 2.5.times.10.sup.-3 (H/m)and magnetic permeability .mu..sub.D of the sheet in the direction 45.degree. to the sheet rolling direction is.mu..sub.D .gtoreq.about 1.5.times.10.sup.-3 (H/m).

Abstract: A process is disclosed for the production of a non-oriented electromagnetic steel strip having its magnetic characteristics uniformly retained in the product coil. The process involves by full- or semi-processing, hot rolling a steel slab containing not more than about 0.03% by weight of C, not more than about 3% by weight of Si and not more than about 2% by weight of Al such that the equation [Si wt %]+3 [Al wt %]-6 [C wt %] is in the range of about 0 to 2; and cold rolling the hot rolled steel strip in a known manner, followed optionally by finish annealing and also optionally by skin-pass rolling. The coil is finish rolled at a peripheral roll speed between about 500 to 1,500 mpm at the final stand. The peripheral roll speed at the final finish rolling stand is also controlled within a range of no more than about 300 mpm. Hot rolling is completed at a temperature Tf (.degree. C.) in an alpha-phase temperature zone and not less than about {750+30 ([Si wt %]+3 [Al wt %]-6 [C wt %])}.

Abstract: This invention is directed to a method of producing a non-oriented magnetic steel sheet involving a series of processes including performing hot rolling process on a steel slab containing no more than about 0.01 wt % C, no more than about 4.0 wt % Si, no more than about 1.5 wt % Mn, no more than about 1.5 wt % Al, no more than about 0.2 wt % P, and no more than about 0.01 wt % S, performing thereto at least one cold rolling process including an optional intermediate annealing process, and then performing a finishing annealing process. The hot rolling process further includes a step which reduces thermal irregularity formed during slab heating; this step involves maintaining a sheet bar, obtained by rough-rolling of the steel slab, at a temperature ranging from about 850.degree. to 150.degree. C. The hot rolling process also includes a step which promotes the growth of fine precipitated particles by applying strain to the sheet bar.