| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a non-oriented electromagnetic steel sheet which suppresses an increase in an alloy cost, has superior surface properties, and has both of excellent mechanical properties and magnetic properties required to a rotor of a motor which rotates at a high speed. <P>SOLUTION: A steel slab for the steel sheet includes 0.06% or less C, 3.5% or less Si, 0.05% to 3.0% Mn, 2.5% or less Al, 0.30% or less P, 0.04% or less S, 0.02% or less N, more than 0.02% Nb, and Nb, Ti, Zr, V and Al in a range of satisfying the expressions of Nb/93+Zr/91+Ti/48+V/51-(C/12+N/14)≤0 and Zr/91+Ti/48+Al/27-N/14>0. The method for manufacturing the non-oriented electromagnetic steel sheet comprises the steps of: heating the steel slab to a temperature between 1,100°C and 1,300°C, then rough-hot-rolling the slab at a cumulative reduction rate of 80% or higher to make a rough bar; and hot-rolling the rough bar, while keeping a temperature of the rough bar after the rough hot rolling step and before a finish hot rolling step to 950°C or higher. <P>COPYRIGHT: (C)2007,JPO&INPIT |
