| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the rapid heating region in the heating step in decarburization/annealing to the temperature at which induction heating can be used in the production of a mirror-finished grain-oriented magnetic steel sheet. <P>SOLUTION: When a silicon steel stock is heated at a temperature of 1,280°C or lower and is thereafter hot-rolled, the hot-rolled sheet is annealed and is then cold-rolled, so as to be a steel sheet with a final sheet thickness, and the steel sheet is subjected to decarburization/annealing, is thereafter nitrided, is coated with a separation agent for annealing essentially consisting of alumina and is subjected to finish annealing, so as to produce a mirror-finished grain-oriented magnetic steel sheet, the hot rolled sheet annealing is conducted in a process where the steel sheet is heated to a prescribed temperature of 1,000 to 1,150°C, is recrystallized and is thereafter annealed at 850 to 1,100°C lower than that temperature, and further, the heating in the heating step in the decarburization/annealing for the steel sheet is conducted under such conditions that the heating rate during the period when the temperature of the steel sheet is in the range of 550 to 720°C is 40°C/sec or higher, preferably 75 to 125°C/sec. <P>COPYRIGHT: (C)2008,JPO&INPIT |
