Abstract: The present invention relates to a process for producing a grain-oriented silicon steel sheet or strip, wherein the crystals of the steel sheet or strip have an orientation of {110}<001> and, further, the steel is easily magnetized in the rolling direction.Since the slab-heating temperature for a grain-oriented silicon steel is considerably higher than that for low carbon steel grades, coarsening of the crystal grains is likely to occur during heating, and the coarse crystal grains are elongated during hot-rolling in the rolling direction and remain in the hot-rolled steel sheet as portions of the grain-oriented silicon steel strip or sheet, where secondary recrystallization becomes incomplete, or as so-called streaks.It is an object of the present invention to provide a novel hot-rolling technique capable of preventing the generation of streaks and capable of enhancing the magnetic flux density of the final product in terms of the B.sub.

Abstract: A process of providing electromagnetic steel strips or sheet with excellent magnetic properties. The process comprises the steps of:irradiating with a laser-beam the surface of an electromagnetic steel sheet which has been finally annealed, thereby locally forming marks of the laser-beam irradiation on the surface of the steel, and;subsequently, subjecting the steel sheet to the formation of an insulating film on the sheet surface at a temperature of the sheet not exceeding 600.degree. C.

Abstract: A continuously cast steel slab for production of a grain-oriented electrical steel sheet having excellent magnetic properties in which at least 95% of the total number of grains constituting an equi-axed crystal zone in said slab has a cross sectional dimension less than 9 mm.sup.2 per one grain.

Abstract: A method of producing a grain-oriented electromagnetic steel sheet comprising the step of subjecting a sheet of hot-rolled steel containing silicon less than 4.5% to more than one operation of cold rolling and more than one operation of annealing, so as to set the thickness of said sheet to that of a commercially standard sheet, and also subjecting the sheet to the step of final high-temperature annealing. Prior to said final high-temperature annealing, part of the surface of said sheet is worked for controlling the growth of secondary recrystallization grains by working the sheets such that lines of less than 3.0 mm wide are formed on the surface of the steel sheet spaced apart at intervals of more than 5.0 mm so that the total effect is to produce worked and unworked regions alternatively arranged in lines across the steel sheet. Such working is effected by mechanical plastic working, local thermal treatment and by chemical treatment.

Abstract: Method for producing a grain-oriented electrical steel sheet or strip having uniform magnetic and film properties said method comprising applying an annealing separator containing one or more metal nitrides, such as, chromium nitride, titanium nitride and vanadium nitride to the steel sheet and annealing the steel sheet at a temperature not lower than 1,100.degree.C.