Method of producing a grain-oriented electrical steel sheet excellent in magnetic characteristics

摘要

A method for producing a grain-oriented electrical steel sheet excellent in magnetic characteristics is provided wherein differentiated use of primary and secondary inhibitors enables production without high temperature slab heating, few glass film defects and no lack of uniformity in secondary recrystallization. A slab containing 0.025 SIMILAR 0.10% of C, 2.5 SIMILAR 4.0% of Si as well as acid-soluble Al, Mn, Cu, N, and Seq = (S + 0.406 Se) of 0.008 SIMILAR 0.05% is reheated to a temperature of more than 1050 DEG C and lower than 1350 DEG C and hot-rolled into a hot-rolled strip. The hot-rolled strip is optionally annealed, subjected to at least one cold rolling with intermediate annealing, whereafter the sheet is decarburization annealed to have primary recrystallization grains after completion of the decarburization annealing of an average diameter of not less than 7 mu m and less than 18 mu m, nitrided up to the start of secondary recrystallization, coated with an annealing separator composed mainly of MgO, and subjected to final finish annealing.