Non-oriented electrical steel sheet and method for producing same

A non-oriented electrical steel sheet consisting of, in mass %,

• Si:
• 3.2 to 4.5%,
• Mn:
• 0.3 to 3.5%,
• sol. Al:
• 0.2 to 2.0%,
• C:
• 0.0010 to 0.0030%,
• N:
• more than 0% to 0.0050% or less,
• O:
• more than 0% to 0.0200% or less,
• P:
• more than 0% to 0.100% or less,
• S:
• more than 0% to 0.0030% or less,
• Ti:
• more than 0% to 0.0030% or less,
• Mo:
• 0 to 0.100%,
• Cr:
• 0 to 1.000%,
• Ni:
• 0 to 0.50%,
• Cu:
• 0 to 0.50%,
• B:
• 0 to 0.0010%,
• Zn:
• 0 to 0.0050%,
• Ga:
• 0 to 0.0050%,
• Ge:
• 0 to 0.0050%,
• As:
• 0 to 0.0100%,
• Sn:
• 0 to 0.20%,
• Sb:
• 0 to 0.10%,
• Ca:
• 0 to 0.0050%,
• La:
• 0 to 0.0050%,
• Ce:
• 0 to 0.0050%,
• Nd:
• 0 to 0.0010%, and
• Mg:
• 0 to 0.0030%,
• with the balance being Fe and impurities,
• wherein:
• a tensile strength TS is higher than 580 MPa;
• when elemental analysis is performed by Auger electron spectroscopy in a grain boundary region of a fracture surface of the non-oriented electrical steel sheet to obtain Auger differential spectrum of Fe and P, and P120/Fe700 that is a ratio of a peak-to-peak value P120 of P around an electron energy of 120 eV to a peak-to-peak value Fe700 of Fe around an electron energy of 700 eV in the Auger differential spectrum obtained is defined as [P]GB, and
• elemental analysis is performed by Auger electron spectroscopy in an intragranular region of a fracture surface of the non-oriented electrical steel sheet to obtain Auger differential spectrum of Fe and P, and P120/Fe700 that is a ratio of a peak-to-peak value P120 of P around an electron energy of 120 eV to a peak-to-peak value Fe700 of Fe around an electron energy of 700 eV in the Auger differential spectrum obtained is defined as [P]IG,
• the [P]GB and the [P]IG satisfy Formula (1);
• a difference ΔS between the tensile strength TS and a yield strength YP is 110 MPa or less;
• and
• an average grain size D (μm) satisfies Formula (2);
• [
• P
• ]
• G
• ⁢
• B
• ⁢
• /
• [
• P
• ]
• I
• ⁢
• G
• >
• 2
• .
• 0
• (
• 1
• )
• D
• ≤
• 100
• -
• 15
• ×
• [
• P
• ]
• G
• ⁢
• B
• ⁢
• /
• [
• P
• ]
• I
• ⁢
• G
• +
• 1
• ⁢
• 500
• /
• TS
• (
• 2
• )
• where, a numerical value of the tensile strength TS (MPa) is substituted for TS in Formula (2).