Non-oriented electrical steel plate and manufacturing process therefor

A non-oriented electrical steel sheet comprising:

• Si:
• 0.1˜2.0 wt %;
• Al:
• 0.1˜1.0 wt %;
• Mn:
• 0.10˜1.0 wt %;
• C:
• ≤0.005 wt %;
• P:
• ≤0.2 wt %;
• S:
• ≤0.005 wt %;
• N:
• ≤0.005 wt %;
• and balance being Fe and other unavoidable impurities, and
• a magnetic permeability of the steel sheet satisfies the following formulas (1) and (2):
• μ10+μ13+μ15≥13982−586.5P15/50 (1);
• μ10+μ13+μ15≥10000 (2),
• wherein μ10, μ13 and μ15 respectively represent the relative magnetic permeability at magnetic inductions of 1.0 T, 1.3 T and 1.5 T at 50 Hz;
• P15/50 represents the iron loss at 50 Hz and under a magnetic induction of 1.5 T, P15/50 in formula (1) is calculated as a value in units of W/kg,
• wherein the steel sheet is prepared by a method comprising operations of steelmaking, hot rolling, acid pickling, cold rolling, and annealing, in sequence, wherein in the hot rolling process, a time interval t2 between the end of a finishing rolling of a intermediate slab and the start of a laminar cooling process is controlled to be ≥5 seconds.