| 摘要 |
PURPOSE: Provided is a production process of high hardness non-grain oriented electric steel sheet which controls Si content among steel, preliminary annealing condition and final annealing condition so that it shows excellence in coercive force and residual magnetic flux density. CONSTITUTION: The production process of high hardness non-grain oriented electric steel sheet comprises the steps of: (i) reheating a silica steel slab wherein 0.004-0.006wt% of C, 2.6-3.0wt% of Si, 0.25-0.35wt% of Mn, less than 0.001wt% of P, less than 0.003wt% of S, 0.4-0.5wt% of Al, less than 0.005wt% of N, residual iron and other impurities are included at 1230-1290deg.C, hot rolling and winding; (ii) preliminarily annealing at 1000-1100deg.C and cool rolling; and (iii) heating to 870-900deg.C at 15-16deg.C/sec and final annealing with keeping temperature.
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