| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a grain-oriented magnetic steel sheet exhibiting excellent core-loss characteristics and noise characteristics when the steel sheet is assembled into an actual transformer. <P>SOLUTION: When a magnetic domain refinement treatment with electron beam irradiation is performed after last final annealing or after tension coating treatment, relationship between a residence time t per one point and a point interval X is controlled to fall within the following ranges according to the output of the electron beam: (1) 0.05≤2(Da<SP POS="POST">.</SP>t)<SP POS="POST">1/2</SP>/X≤1.5 when the beam output is lower than 600 W; (2) 0.03≤2(Da<SP POS="POST">.</SP>t)<SP POS="POST">1/2</SP>/X≤0.8 when the beam output is 600-1,200 W; and (3) 0.01≤2(Da<SP POS="POST">.</SP>t)<SP POS="POST">1/2</SP>/X≤0.2 when the beam output exceeds 1,200 W, wherein Da: a thermal diffusion rate (22.7x10<SP POS="POST">-6</SP>m<SP POS="POST">2</SP>/s at 300K in Fe), t: a residence time per one point (s), X: a point interval (mm). <P>COPYRIGHT: (C)2012,JPO&INPIT |
