| 摘要 |
PURPOSE:To stably and inexpensively obtain a soft magnetic steel material excellent in coercive force and magnetic flux density by specifying respective contents of C, Mn, P, S, N, O, Si, Al, Ti, V, and Mo and also specifying ferrite grain size. CONSTITUTION:This steel material has a composition which contains, by weight, <=0.007% C, <=0.5% Mn, <=0.2% P, <=0.01% S, <=0.01% T.N, and <=0.005% T.O and into which at least one or more kinds among Si, Sol.Al, Ti, V, and Mo are incorporated in the range where R defined by R=16Si+22Al+25Ti+20V +8Mo satisfies 15<=R<=70. Further, average ferrite grain size (d)(mm) is regulated so that it satisfies, in the relations with the thickness or diameter (t)(mm) of the steel material, the following: d>=0.2 when t=0.2 to <0.5; d>=tX0.4 when t=0.5 to <1.3; and d>=0.5 when t>=1.3. By finally heattreating this steel material at 850-1300 deg.C, the above ferrite grain size can be obtained. |
