| 摘要 |
A hot rolled steel sheet includes, as a chemical composition, at least one selected from Ti, REM, and Ca, and includes, as a metallographic structure, a ferrite as a primary phase, at least one of a martensite and a residual austenite as a secondary phase, and plural inclusions, wherein a total length in the rolling direction of both inclusion-cluster whose length in the rolling direction is 30 mum or more and independent-inclusion whose length in the rolling direction is 30 mum or more is 0 mm to 0.25 mm per 1 mm2. |
