PURPOSE: To produce a non-directional silicon steel sheet of which the iron loss is decreased by the increased heating rate in the stage of continuous finish annealing by decreasing considerably S, O and N among the unavoidable impurities contained in a blank material for a silicon steel and hot rollig and cold rolling the blank material to a final thickness.
CONSTITUTION: A blank material for a silicon steel contg., by weight %, ≤0.005 % C, 2.5W4.0% Si, 0.25W1.00% Al and 0.1W1.0% Mn is hot rolled according to a conventional method. The hot rolled material is rolled to a final thickness by once or twice of cold rolling including intermediate annealing and is then subjected to continuous finish annealing, whereby a non-directional silicon steel sheet is produced. S, O and N among the impurities contained unavoidably in the blank material are suppressed to ≤15ppm, ≤20ppm and ≤25ppm respectively and the heating rate at the continuous finish annealing is maintained at ≥300°C/ min in the above-mentioned stage. Then the non-directinal silicon steel sheet having excellent characteristics, particularly low iron loss is thus obtd.
KOMATSUBARA MICHIROU
NAKAMURA HIROTO
MATSUMURA HIROSHI
ITOU ISAO
| JPS5716121A | 1982-01-27 | |||
| JPS563625A | 1981-01-14 |