PRODUCTION OF HIGH MAGNETIC FLUX DENSITY SILICON STEEL SHEET EXCELLENT IN MAGNETIC PROPERTY AND FILM PROPERTY

摘要

PURPOSE: To improve the surface film and magnetic properties of a steel sheet by specifying the oxygen content and nitrogen content after nitriding in a sheet subjected to primary recrystallization annealing. ;CONSTITUTION: Molten steel contg. 1 to 7% Si and 0.045 to 0.20% P is subjected to hot rolling and cold rolling, and primary recrystallization annealing is executed. Next, at the time of adding N required for an inhibitor, the oxygen content by a chemical analysis method in the sheet subjected to the primary recrystallization annealing is regulated to 25 to 900ppm. The nitrogen content after the subsequent nitriding is regulated to 120 to 400ppm. The nitrided steel sheet is coated with a separation agent for annealing, and secondary recrystallization annealing is executed. Since N required for an inhibitor is efficiently added after the primary recrystallization annealing and a primary film is stably formed on the surface of the silicon steel in the case of the secondary recrystallization annealing, the grain-oriented silicon steel sheet having high magnetic flux density and low iron loss can be produced.;COPYRIGHT: (C)1994,JPO&Japio