Grain-oriented electrical steel sheet

1. A grain-oriented electrical steel sheet comprising a steel layer and an insulation coating arranged on the steel layer, characterized in that:

the steel layer includes, as a chemical composition, by mass %,

0.0003 to 0.005% of C,

2.9 to 4.0% of Si,

2.0 to 4.0% of Mn,

0.003 to 0.018% of sol. Al,

0.005% or less of S,

0 to 0.20% of Sn,

0 to 0.20% of Sb, and

a balance consisting of Fe and impurities;

a silicon content and a manganese content expressed in mass % in the chemical composition of the steel layer satisfy 1.2%≤Si−0.5×Mn≤2.0%;

a tin content and an antimony content expressed in mass % in the chemical composition of the steel layer satisfy 0.005%≤Sn+Sb≤0.20%;

the insulation coating is arranged in directly direct contact with the steel layer; and

the magnetic flux density B8 along the rolling direction is 1.60 to 1.77 T.

2. The grain-oriented electrical steel sheet according to claim 1 , wherein

the steel layer includes, as the chemical composition, by mass %,

0.004 to 0.20% of Sn, and

0.001 to 0.20% of Sb.

3. A grain-oriented electrical steel sheet comprising a steel layer and an insulation coating arranged on the steel layer, characterized in that:

the steel layer includes, as a chemical composition, by mass %,

0.0003 to 0.005% of C,

2.9 to 4.0% of Si,

2.0 to 4.0% of Mn,

0.003 to 0.018% of sol. Al,

0.005% or less of S,

0 to 0.20% of Sn,

0 to 0.20% of Sb, and

a balance including Fe and impurities;

a silicon content and a manganese content expressed in mass % in the chemical composition of the steel layer satisfy 1.2%≤Si−0.5×Mn≤2.0%;

a tin content and an antimony content expressed in mass % in the chemical composition of the steel layer satisfy 0.005%≤Sn+Sb≤0.20%;

the insulation coating is arranged in direct contact with the steel layer; and

the magnetic flux density B8 along the rolling direction is 1.60 to 1.77 T.