PRODUCTION OF GRAIN-ORIENTED SILICON STEEL SHEET EXCELLENT IN LOW MAGNETIC FIELD CORE LOSS CHARACTERISTIC COMPARED TO HIGH MAGNETIC FIELD CORE LOSS CHARACTERISTIC

摘要

PROBLEM TO BE SOLVED: To stably obtain a grain-oriented silicon steel sheet excellent in low magnetic field core loss characteristics compared to high magnetic field core loss characteristics suitable for an EI core or the like by using a silicon steel slab having a specified compsn. as the stock and controlling coarse grains in which diameter equivalent to a circle is regulated to specified value or above in the steel sheet after decarburizing annealing so as to requlate the ratio of the area occupied in the cut face of the steel sheet to specified value or above. ;SOLUTION: A silicon steel slab contg., by weight, 0.02 to 0.07% C, 2.0 to 4.5% Si, 0.03 to 2.5% Mn, 0.005 to 0.030% Al and 0.003 to 0.010% N is subjected to hot rolling, is subjected to hot rolled sheet annealing and is thereafter subjected to cold rolling for one time or two times including process annealing to regulate its sheet thickness into final one, which is subjected to decarburizing annealing, is applied with a separation agent for annealing and is subjected to finish annealing to obtain a grain-oriented silicon steel sheet. At this time, in the case the average diameter (that equivalent to a circle) of the crystal grains measured in the cut face of the steel sheet after the decarburizing annealing is defined as (d), control is executed in such a manner that the coarse grains in which diameter equivalent to a circle is regulated to ≥2d occupy ≥3% of the cut face of the decarburized and annealed sheet.;COPYRIGHT: (C)1998,JPO