| 摘要 |
An object of the present invention is to propose a method for stably achieving a good iron loss reducing effect by rapid heating treatment of a steel sheet in a case where primary recrystallization annealing including rapid heating treatment is carried out in a method for manufacturing a grain oriented electrical steel sheet using an inhibitor-free material. Specifically, the present invention provides a method for manufacturing a grain oriented electrical steel sheet, comprising the steps of: preparing a steel slab in which contents of inhibitor components have been reduced, i.e. content of Al: 100 ppm or less, and contents of N, S and Se: 50 ppm, respectively; subjecting the steel slab to hot rolling and then either a single cold rolling process or two or more cold rolling processes interposing intermediate annealing(s) therebetween to obtain a steel sheet having the final sheet thickness; and subjecting the steel sheet to primary recrystallization annealing and then secondary recrystallization annealing, wherein the primary recrystallization annealing includes heating the steel sheet to temperature equal to or higher than 700°C at a heating rate of at least 150°C/s, cooling the steel sheet to a temperature range of 700°C or lower, and then heating the steel sheet to soaking temperature at the average heating rate not exceeding 40°C/s in a subsequent heating zone. |
