| 摘要 |
PROBLEM TO BE SOLVED: To produce a nonoriented silicon steel sheet not only having excellent magnetic properties but also having excellent uniformity of the properties in a coil. SOLUTION: In the steel sheet having a composition comprising, by mass,≤0.040% C, 0.05 to 3.5% Si, Mn in≤1.0% also so as to satisfy Si/Mn≤2,≤0.0005% Al,≤0.003% S,≤0.15% P,≤0.020% N and≤0.10% Cu, and the balance Fe with inevitable impurities, the quantity, size and number density of Cu sulfides in a final product are limited to specified ranges over the whole length of a coil. For this purpose, a slab after casting is cooled or is held hot in such a manner that the residence time in the temperature range of 950 to 500°C is controlled to≥10 min, is thereafter, without holding its temperature to the one therebelow, inserted into a heating furnace, is heated in the heating furnace in such a manner that the temperature does not exceed 1,200°C regarding all the parts of the slab, and is unloaded from the heating furnace at≤1,100°C so as to start hot rolling. COPYRIGHT: (C)2005,JPO&NCIPI
|
