| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a grain-oriented magnetic steel sheet for obtaining a uniform glass film and excellent magnetic properties by controlling the heat cycle in a temp. rising stage and atmospheric conditions in finish annealing in a glass film forming stage. SOLUTION: In the method for producing a grain-oriented electric steel sheet in which a hot rolled sheet essentially contg. 0.03 to 0.100% C and 2.5 to 4.5% Si is annealed if necessary, is subjected to cold rolling by one time or two times interposing annealing to obtain a final one having mede its sheet thickness, is subjected to decarburizing annealing, is subjected to nitriding annealing if necessary, is coated with a separation agent for annealing, is subjected to finish annealing and is subjected to insulated film treatment and heat flattening, as the finish annealing conditions, the heating time in the temp. range of 750 to 1,050 deg.C in the temp. rising stage is made to 8.3 to 50 hr on the average, also PH2 O/PH2 =0.001 to 0.02 is satisfied, and the annealing is executed in either atmospheric gas of gaseous H contg. <=50% N2 or gaseous H2 . |
