| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of producing a grain-oriented magnetic steel sheet having low iron loss and little variation in a value of iron loss.SOLUTION: The method of producing a grain-oriented magnetic steel sheet is provided in which a steel raw material containing, by mass%, C:0.002 to 0.10%, Si:2.0 to 8.0%, Mn:0.005 to 1.0%, Al:less than 0.01%, N:less than 0.0050%, Se:less than 0.0030% and S:less than 0.0050% is hot rolled, cold rolled, subjected to primary recrystallization annealing and nitriding treatment, then an annealing-separation agent is applied onto the resulting cold rolled steel, and the cold rolled steel sheet is subjected to finish annealing. In the method, variation in a primary particle diameter in a steel sheet width direction after the primary recrystallization annealing is made to fall within 10% by rapid heating the cold rolled steel at 50°C/s or more between 200 to 700°C in a heating process of the primary recrystallization annealing, and subjecting the cold rolled steel to a soaking treatment for holding the cold rolled steel at any temperature between 250 to 600°C for 1 to 10 seconds, and setting retention time in a following range between 700 to 800°C at 5 seconds or more. |
