| 摘要 |
PURPOSE: To produce a thin nonoriented silicon steel sheet low in core loss in a high frequency region by subjecting a nonoriented silicon steel slab contg. specified amounts of Si, Al, C and N to hot rolling and cold rolling and thereafter prescribing the atmosphere and dew point in final annealing in accordance with the Al content. CONSTITUTION: A nonoriented silicon steel slab contg., by weight, 0.5 to 4% Si and <=1% Al so as to satisfy Si+Al; <=4.5%, <=0.005% C and <=0.005% N is subjected to hot rolling and is subjected to cold rolling for one time or cold rolling for two times including process annealing. Next, at the time of executing final annealing, in the case of <=0.004% Al, the atmosphere is formed of a nonoxidizing one, and the dew point(DP) at this time is regulted to DP>=-20 deg.C. In the case of >0.004 to 1% Al, the atmosphere is formed of a nonoxidizing or nonnitriding one, and the dew point (DP) at this time is regulated to DP<=-50-10×log [10×Al%] ( deg.C). Thus, the nonoriented silicon steel sheet low in core loss in a high frequency region and having 0.1 to 0.25mm sheet thickness can be obtd. |
