Non-oriented electrical steel sheet, method for manufacturing same, and motor core comprising same

A method for manufacturing a non-oriented electrical steel sheet, the method comprising:

• manufacturing a hot-rolled sheet by hot rolling a slab containing, by wt %:
• 2.0 to 6.5% of Si, 0.1 to 1.3% of Al, 0.3 to 2.0% of Mn, 0.005 to 0.06% of Cr, and a balance of Fe and inevitable impurities;
• removing scale present on a surface of the hot rolled sheet;
• manufacturing a cold-rolled sheet by cold rolling the hot-rolled sheet from which the scale has been removed;
• and
• subjecting the cold-rolled sheet to cold-rolled sheet annealing,
• wherein the removing the scale comprises removing the scale by projecting a shot ball onto a steel sheet in an amount of 15 to 35 kg/(min·m2).

A motor core comprising:

• a stator made by stacking a plurality of non-oriented electrical steel sheets, and
• a rotor made by stacking a plurality of non-oriented electrical steel sheets,
• wherein the non-oriented electrical steel sheets in the rotor comprise, respectively:
• a steel sheet base material containing, by wt %:
• 2.0 to 6.5% of Si, 0.1 to 1.3% of Al, 0.3 to 2.0% of Mn, 0.005 to 0.06% of Cr, and a balance of Fe and other inevitable impurities, and an insulating coating film positioned on the steel sheet base material, and Formula 1 below is satisfied, and
• wherein the non-oriented electrical steel sheets in the stator comprise, respectively:
• a steel sheet base material containing, by wt %:
• 2.0 to 6.5% of Si, 0.1 to 1.3% of Al, 0.3 to 2.0% of Mn, 0.005 to 0.06% of Cr, and a balance of Fe and other inevitable impurities, and an insulating coating film positioned on the steel sheet base material, and Formula 2 below is satisfied.
• 0.1
• ≥
• [
• Mn
• ⁢
• coating
• ⁢
• film
• ]
• ⁢
• /
• [
• Mn
• ⁢
• 50
• ]
• [
• Formula
• ⁢
• 1
• ]
• 10
• ≥
• [
• Mn
• ⁢
• coating
• ⁢
• film
• ]
• ⁢
• /
• [
• Mn
• ⁢
• 50
• ]
• ≥
• 1
• [
• Formula
• ⁢
• 2
• ]
• (in Formulas 1 and 2, [Mn coating film] refers to an average content of Mn (wt %) in the insulating coating film, and [Mn50] refers to a content of Mn (wt %) at a depth of 50 μm from an interface between the steel sheet base material and the insulating coating film toward an inside of the steel sheet base material.)