Abstract: An electromagnetic steel sheet having a low iron loss and a high magnetic flux density, with silicon, nitrogen and an added element bismuth or germanium prior to secondary recrystallization, to accelerate precipitation of fine BN and silicon nitride, improving the texture of the primary recrystallized grains of the steel sheet immediately before subjecting it to secondary recrystallization annealing, and combining the primary recrystallization annealing, cold rolling and further the texture improving treatment. Addition of bismuth or germanium or both to the steel prior to secondary recrystallization is combined with primary recrystallization annealing and warm rolling in the presence of limited aluminum and vanadium impurities limited to 0.002 wt % Al or less and 0.010 wt % V or less.

Abstract: A grain-oriented electromagnetic steel sheet is provided which has a low ratio of iron loss in a weaker magnetic field to that in a stronger magnetic field and has special advantage in EI cores and the like. Also provided is a process for producing that steel sheet. The grain-oriented electromagnetic steel sheet is characterized in that its crystal grains of important components are specified in terms of their proportions in number, and the contents of Al, Ti and B, with a forsterite film formed on a surface of the steel sheet. In the process a low-Al silicon slab is heated at below 1,250° C. before hot rolling and the hot-rolled sheet is annealed with a temperature rise in the range of from 5 to 25° C./sec and at a temperature of from about 800 to 1,000 for a period of time of shorter than about 100 seconds.

Abstract: Electromagnetic steel sheet from a high-purity steel slab, composed essentially of Si 2.0 to 8.0 wt %, Mn 0.005 to 3.0 wt % and Al 0.0010 to 0.012 wt % with each of Se, S, N and O each not more than 30 ppm.

Abstract: Grain-oriented magnetic steel sheet made by the method-including hot rolling and final finish annealing, wherein (1) the O content in the steel slab is limited to up to about 30 ppm; (2) for the entire steel sheet having final thickness including an oxide film before final finish annealing, from among impurities, the Al content is limited to up to about 100 wtppm, and the respective contents of B, V, Nb, Se, S, P, and N, to up to about 50 wtppm each; and (3) during final finish annealing, the N content in the steel is, at least in the temperature region of from about 850 to 950° C., limited within the range of from about 6 to 80 wtppm.

Abstract: Grain-oriented magnetic steel sheet made by the method comprising of hot rolling and final finish annealing, wherein

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: Grain-oriented electrical steel sheet having excellent magnetic characteristics in which shearing angles of grain directions [001] of secondary recrystallized grains from a rolling direction have an average value of about 4.degree. or less, wherein the area % of secondary recrystallized grains having a length of about 60 mm or more in the rolling-orthogonal direction is about 85% or more; with respect to recrystallized micro grains, the area % of crystal grains having a grain diameter of 2 to 20 mm is about 0.2% or more and about 10% or less; and the average value of angles formed with the steel sheet surface by grain directions [001] is about 1.5.degree. or more and about 5.0.degree. or less; in a grain-oriented electrical steel sheet of a high magnetic flux density (B.sub.8 .gtoreq.1.96 T) low iron loss is achieved without providing magnetic domain-refining treatment, very low iron loss value by forming grooves on the steel sheet surface, smoothening the steel sheet surface or a combination thereof.

Abstract: In a grain oriented electrical steel sheet used for cores of transformers and generators, a high alignment degree of grain orientations reduces iron loss, by precipitating very fine AlN or/and BN and providing strong inhibiting effect against the growth of the primary recrystallized grains, providing radically improved texture and grain structure in the steel.

Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet. Transformers based upon the steel sheet have excellent magnetic characteristics (iron loss and magnetic flux density) together with strain resistance, and the steel sheet has good practical device characteristics (building factor) after being assembled into a transformer.

Abstract: A grain-oriented electromagnetic steel sheet is provided which has a low ratio of iron loss in a weaker magnetic field to that in a stronger magnetic field and has special advantage in EI cores and the like. Also provided is a process for producing that steel sheet. The grain-oriented electromagnetic steel sheet is characterized in that its crystal grains of important components are specified in terms of their proportions in number, and the contents of Al, Ti and B, with a forsterite film formed on a surface of the steel sheet. In the process a low-Al silicon slab is heated at below 1,250.degree. C. before hot rolling and the hot-rolled sheet is annealed with a temperature rise in the range of from 5 to 25.degree. C./sec and at a temperature of from about 800 to 1,000 for a period of time of shorter than about 100 seconds.

Abstract: A method of producing a grain-oriented magnetic steel sheet exhibiting a very low core loss and high magnetic flux density uses a slab of silicon steel containing Al, B, N, and S and/or Se. The method employs hot rolling conducted such that the rolling reduction falls within the range of from about 85 to 99%, and the hot-rolling finish temperature falls within the range of from 950.degree. to 1150.degree. C. and is based on the contents of Si, Al and B. The hot-rolled steel sheet is rapidly cooled at a cooling rate of about 20.degree. C./s and is coiled at a temperature of about 670.degree. C. or lower. Hot-rolled sheet annealing or intermediate annealing is executed by heating the hot-rolled steel sheet up to about 800.degree. C. at a heating rate of from 5.degree. to 25.degree. C./s and holding at a temperature of from about 800.degree. to 1125.degree. C. for a period not longer than about 150 seconds.

Abstract: Grain-oriented electrical steel sheet having a very low iron loss with controlled area ratio of fine grains, average grain size of coarse grains, obliquity of the grain boundary line of coarse grains, permeability under 1.0 T, and film tension.

Abstract: Producing a grain oriented silicon steel sheet by controlling physical properties of the oxides layer, formed in decarburization annealing, in the surface layer of a steel sheet. A silicon compound is adhered to the surface of steel sheet before the decarburization annealing in an amount ranging from about 0.5 to 7.0 mg per square meter, expressed as Si, and the atmosphere of an earlier portion of the temperature holding process is adjusted to a ratio of steam partial pressure to the hydrogen partial pressure of less than about 0.7, and the atmosphere of the temperature rising process up to the temperature holding process is adjusted to an atmospheric composition lower than the atmospheric composition of the earlier portion of the temperature holding process, and the atmosphere of a later part of the temperature holding process is adjusted to an atmospheric composition lower than the atmospheric composition of the earlier part of the temperature holding process and in a range from about 0.005 to 0.2.

Abstract: Grain-oriented electrical steel sheet having a very low iron loss with controlled area ratio of fine grains, average grain size of coarse grains, obliquity of the grain boundary line of coarse grains, permeability under 1.0 T, and film tension.

Abstract: A method of manufacturing a grain-oriented silicon steel sheet exhibiting excellent magnetic characteristics over the entire length of a coil thereof, which involves hot rolling a silicon steel slab containing aluminum and suitable for making a grain-oriented silicon steel sheet; annealing the steel sheet, as the need arises; cold rolling the steel sheet to a final thickness, the cold rolling including an intermediate annealing process; performing a heat effect treatment before, during or after the cold rolling; performing a decarburizing annealing; and performing a final annealing process. The method inhibits oxidation of the surfaces of the steel sheet during the cold rolling.

Abstract: A method of manufacturing a grain-oriented silicon steel sheet having excellent and uniform magnetic characteristics by improving the magnetic flux density of a silicon coil cold rolled to a thin thickness without increasing a Si content. The method comprises controlling steel sheet temperature along the rolling direction of a coil immediately downstream of the outlet roll bites of one or more rolling paths to about 15.degree. C. or less, and controlling the temperature of one or more of the rolling paths between about 150.degree. C. to about 350.degree. C.

Abstract: A method of manufacturing a grain-oriented silicon steel sheet having excellent and stable magnetic characteristics which includes the steps of subjecting a silicon steel slab to hot rolling to form a hot-rolled sheet, cold rolling the hot-rolled sheet at least once with intermediate annealings between successive cold rollings to form a cold-roiled sheet, and thereafter primary recrystallization annealing the cold-rolled sheet to form a primary recrystallized sheet. The primary recrystallized sheet is then final finish annealed, which includes a secondary recrystallization annealing and a purifying annealing during which the steel slab is coated with an annealing separator. The coercive force of the primary recrystallized steel sheet is controlled to a predetermined range before the start of secondary recrystallization.

Abstract: A decarburized steel sheet for a thin oriented silicon steel sheet having improved magnetic and coating characteristics and a method of producing the same. Silicon steel strip is hot-rolled, cold-rolled to a final thickness of about 0.28 mm or less, subjected to decarburization/primary-recrystallization annealing, coated with an annealing separator, and thereafter subjected to finishing annealing. In the decarburization/primary-recrystallization annealing step, a novel subscale is formed at the steel sheet surface having a fayalite-silica composition ratio in accordance with an infrared reflection absorbance ratio of about 0.5 to 5.5, and a marked oxygen amount of about 0.4 to 1.6 g/m.sup.2.

Abstract: 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.

Abstract: A method of manufacturing a grain-oriented silicon steel sheet exhibiting excellent magnetic characteristics over the entire length of a coil thereof, which involves hot rolling a silicon steel slab containing aluminum and suitable for making a grain-oriented silicon steel sheet; annealing the steel sheet, as the need arises; cold rolling the steel sheet to a final thickness, the cold rolling including an intermediate annealing process; performing a heat effect treatment before, during or after the cold rolling; performing a decarburizing annealing; and performing a final annealing process. The method inhibits oxidation of the surfaces of the steel sheet during the cold rolling.