METHOD FOR MANUFACTURING GRAIN ORIENTED SILICON STEEL SHEET HAVING EXCELLENT MAGNETIC CHARACTERISTIC

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a perfect solid solution nitriding magnetic flux density grain-oriented silicon steel sheet having satisfactory glass film formation and excellent magnetic characteristics. SOLUTION: The method for manufacturing the grain-oriented silicon steel sheet having the excellent magnetic characteristics and glass film by; soaking a steam partial pressure and temperature during primary recrystallization annealing at 810 to 890°C for 60 to 180 seconds and regulating the PH2O/PH2of the atmosphere to 0.30 to 0.70; maintaining the temperature conditions in the subsequent second half under 850 to 900°C for 5 to 30 second; dividing PH2O/PH2of the atmosphere to two stages of≤0.20 second, and thereafter, performing nitriding; regulating the steel sheet oxygen before secondary recrystallization annealing to≥450 to≤700 ppm in oxygen in terms of a sheet thickness 0.30 mm; consisting the atmosphere from room temperature up to 950°C in the temperature at the hottest point in the outer peripheral part of the coil in the subsequent secondary recrystallization annealing of 25 to 75% nitrogen and the balance hydrogen; and maintaining the PH2O/PH2at 0.01 to 0.15. COPYRIGHT: (C)2007,JPO&INPIT