Abstract: A method of producing a grain oriented silicon steel thin sheet having excellent magnetic properties. A silicon steel slab containing Cu, Se and Sb as inhibitor-forming elements is hot rolled to form a hot-rolled sheet, followed by cold rolling at least twice including intermediate annealing to form a cold-rolled sheet having a final thickness of about 0.10 to 0.25 mm, decarburization and primary recrystallization annealing, and then final finish annealing. The temperature of the material to be rolled on the inlet side of the hot finish rolling mill is about 1000.degree. to 1150.degree. C. the surface temperature of the work rolls of the first stand of the hot finish rolling mill immediately before contact with the material to be rolled is about 100.degree. C. or less the total rolling reduction of the hot finish rolling is about 93 to 97%, the intermediate annealing is effected at a temperature of about 900.degree. to 1050.degree. C.

Abstract: In grain oriented silicon steel sheets containing MnSe as a main inhibitor, an iron loss is reduced by increasing the magnetic flux density and realizing the thinning of product thickness and fine division of crystal grains while utilizing the stability of secondary recrystallization as a merit of such a sheet. In this case, 0.02-0.30% of Cu is added to a slab of the above grain oriented silicon steel, and particularly the decarburization annealing and/or the final finish annealing are carried out under particular conditions.

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 manufacturing an oriented silicon steel sheet which achieves a high magnetic flux density while reducing the core loss. A silicon steel sheet containing Al and Sb as inhibitor components is cold-rolled once or a plurality of times. During cooling for annealing before final cold rolling, a small strain is created on the sheet and the temperature is within a certain range. Carbide precipitation is suitably controlled to precipitate carbides comparatively coarsely in grains.

Abstract: The present invention realizes the stable production of grain oriented silicon steel sheets having excellent magnetic properties under high productivity through effectively combining aging treatment with tandem rolling, in which cold rolling is effected until a final thickness is attained. In the final cold rolling step of the production of the grain oriented silicon steel sheets, the tandem rolling is first effected, and then continuous heat treatment is effected, preferably under application of tension.

Abstract: 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.

Abstract: An oriented silicon steel sheet having a very high magnetic flux density is produced from an oriented silicon steel containing AlN as the main inhibitor and also containing Sb by a method adapted to prevent the loss of the inhibiting ability of the surface layer of the steel, and to improve cooling conditions in annealing before the final cold rolling. The steel is hot rolled, subjected to at least one time the combination of annealing and cold rolling wherein the final cold rolling is performed with a rolling reduction of about 80 to 95%, subjected to decarburization and primary recrystallization annealing, and subjected to, after coating an annealing separation agent, final finish annealing. Before annealing is performed before the final cold rolling, a nitriding promoter is applied to the surface of the steel sheet, and the partial-pressure ratio of N.sub.2 in the atmosphere for that annealing is adjusted to a value of not less than about 20%.

Abstract: A method of manufacturing an oriented silicon steel sheet improved in magnetic characteristics, in which a hot-rolled steel sheet of oriented silicon steel containing about 0.01 to 0.10% by weight of Al and about 0.01 to 0.04% by weight of Sb as inhibitor components is heat-treated and cold-rolled one time or two or more times to have a final thickness. In the final heat treatment and final cold rolling alone, the steel sheet is quenched from a temperature of about 900.degree. to 1,100.degree. C. to a temperature equal to or lower than about 50.degree. C., is heat-treated at about 50.degree. to 150.degree. C. for about 30 sec. to 30 min. while applying a tensile stress of about 0.5 to 20 kg/mm.sup.2, is thereafter cold-rolled by a reduction rate of about 35 to 70% in a tandem rolling method, is aged at about 200.degree. to 400.degree. C. for about 10 sec. to 10 min., and is finished by cold rolling to have the final thickness.

Abstract: The production of grain oriented silicon steel sheets comprises a combination of hot rolling step, cold rolling step, decarburization and primary recrystallization annealing step, annealing separator applying step and secondary recrystallization annealing and purification annealing step. In this case, the cold rolled sheet is subjected to an electrolytic degreasing in a silicate bath containing an iron concentration of 50-5000 mg/l, and Cu is adhered to the surface(s) of the sheet after the decarburization and primary recrystallization annealing in an amount of 400-2000 mg/m.sup.2 per one-side surface.

Abstract: A semi-process non-oriented electromagnetic steel strip having low core loss and high magnetic permeability is provided which consists essentially of, in % by weight, up to 0.02% of C, 0.2 to 2.0% of Si, 0.1 to 0.6% of Al, 0.02 to 0.10% of P, 0.5 to 1.5% of Mn, 0.1 to 1.0% of Ni, and optionally up to 0.6% of Cu, and optionally 0.01 to 0.2% of Sb and/or Sn, and a balance of iron and inevitable impurities. Magnetic properties are further improved when it is manufactured by hot rolling a slab having the composition at a temperature of from 1,100.degree. to 1,200.degree. C., completing hot finish rolling at a temperature of at least 700.degree. C. in the austenite region, annealing the strip at a temperature from 800.degree. to 880.degree. C. for at least one hour, cold rolling and annealing the strip, and optionally, skin pass rolling with a reduction of 2 to 12%.

Abstract: 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.

Abstract: A semi-processed non-oriented electromagnetic steel strip having low core loss and high magnetic permeability is provided which consists essentially of, in % by weight, up to 0.02% of C, 0.2 to 2.0% of Si, 0.1 to 0.6% of Al, 0.02 to 0.10% of P, 0.5 to 1.5% of Mn, 0.1 to 1.0% of Ni, and optionally up to 0.6% of Cu, and optionally 0.01 to 0.2% of Sb and/or Sn, and a balance of iron and inevitable impurities. Magnetic properties are further improved when it is manufactured by hot rolling a slab having the composition at a temperature of from 1,100.degree. to 1,200.degree. C., completing hot finish rolling at a temperature of at least 700.degree. C. in the austenite region, annealing the strip at a temperature from 800.degree. to 880.degree. C. for at least one hour, cold rolling and annealing the strip, and optionally, skin pass rolling with a reduction of 2 to 12%.

Abstract: When producing a semi-process electromagnetic steel sheet by a series of process steps including cold rolling, annealing and skin pass rolling, in this order, a hot rolled sheet containing not more than 0.02 wt. % of C, 0.1 to 1.0 wt. % of Si, 0.5 to 1.5 wt. % of Mn, 0.1 to 0.6 wt. % of Al and 0.02 to 0.10 wt. % of P and optionally containing at least one of 0.1 to 1.0 wt.% of Ni, 0.01 to 0.2 wt. % in sum of Sb and/or Sn, and not more than 0.6 wt.

Abstract: 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.

Abstract: A high adhesion uniform forsterite insulating film can be formed on the surface of a grain-oriented silicon steel sheet by the application of an annealing separator consisting mainly of magnesia having a narrow activity distribution defined by the citric acid activity of the magnesia which varies depending upon the variation of final reaction ratio of the magnesia as determined by the method for measuring the citric acid activity of magnesia, where the final reaction ratio of the magnesia is the ratio of that amount of the magnesia which finally reacts with citric acid to the total amount of magnesia mixed with the citric acid.

Abstract: Forsterite insulating films having a high adhesion on an oriented silicon steel sheet are formed by a method wherein an annealing separator consisting mainly of magnesia is applied on surfaces of the oriented silicon steel sheet and the steel sheet is wound up into a coil-form and then annealed at high temperatures to form forsterite insulating films, which is characterized by that the content of water carried into the coil together with the annealing separator is controlled depending upon the content of CaO component carried into the coil together with the annealing separator.

Abstract: A forsterite insulating film having a good adhesion property to a grain-oriented silicon steel sheet with a high magnetic induction is composed of forsterite grains having a mean grain size of not more than 0.7 .mu.m. The forsterite insulating film is formed by annealing a coil of a cold rolled silicon steel strip having a final gauge in an annealing furnace under an inert gas atmosphere at a constant temperature keeping stage of 800.degree.-920.degree. C so as to fully develop secondary recrystallized grains and then under hydrogen gas atmosphere at a temperature rising stage up to 1,150.degree.-1,250.degree. C and a constant temperature keeping stage of 1,150.degree.-1,250.degree. C during the final annealing, provided that an average dew point of the atmosphere is within a range of -20.degree. C to +20.degree. C in the temperature rising stage up to 1,150.degree.-1,250.degree. C and not more than +10.degree. C in the constant temperature keeping stage of 1,150.degree.-1,250.degree. C.