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

A non-oriented electrical steel sheet having a chemical composition in mass % of:

• C:
• 0.0100% or less,
• Si:
• 2.6% to 4.1%,
• Mn:
• 0.1% to 3.0%,
• P:
• 0.15% or less,
• S:
• 0.0013% or less,
• N:
• 0.0050% or less,
• Al:
• 0.1% to 2.0%,
• Mg:
• 0.0002% to 0.0100%,
• B:
• 0.0001% to 0.0010%,
• one or more selected from Sn and Sb:
• 0% to 0.100%,
• Cr:
• 0% to 0.1%,
• Ni:
• 0% to 5.0%,
• Cu:
• 0% to 5.0%,
• Ca:
• 0% to 0.010%, and
• rare earth elements (REM):
• 0% to 0.010%, with the balance of Fe and impurities,
• wherein a tensile strength in a rolling direction of the non-oriented electrical steel sheet is 667 MPa or more,
• wherein an area fraction of a crystal structure A composed of crystal grains having a grain size of 100 um or more is 1% to 30% in a cross section parallel to a rolled plane of the non-oriented electrical steel sheet,
• wherein an average grain size of a crystal structure B which is a crystal structure other than the crystal structure A is 15 μm or more and 40 μm or less, and
• wherein a Vickers hardness HvA of the crystal structure A and a Vickers hardness HvB of the crystal structure B satisfy Equation 1 below,
• (
• HvA
• 2
• +
• HvB
• 2
• )
• /
• 2
• -
• (
• HvA
• +
• HvB
• )
• 2
• /
• 4
• ≤
• 7
• .
• 0
• .
• Equation
• ⁢
• 1