Steel member and method of manufacturing same

A steel member comprising, as a chemical composition, by mass %:

• C:
• 0.10% to 0.60%;
• Si:
• 0.40% to 3.00%;
• Mn:
• 0.30% to 3.00%;
• P:
• 0.050% or less;
• S:
• 0.0500% or less;
• N:
• 0.010% or less;
• Ti:
• 0.0010% to 0.1000%;
• B:
• 0.0005% to 0.0100%;
• Cr:
• 0% to 1.00%;
• Ni:
• 0% to 2.0%;
• Cu:
• 0% to 1.0%;
• Mo:
• 0% to 1.0%;
• V:
• 0% to 1.0%;
• Ca:
• 0% to 0.010%;
• Al:
• 0% to 1.00%;
• Nb:
• 0% to 0.100%;
• Sn:
• 0% to 1.00%;
• W:
• 0% to 1.00%;
• REM:
• 0% to 0.30%;
• and
• a remainder consisting of Fe and impurities,
• wherein a metallographic structure includes, by a volume fraction, 60.0% to 85.0% of martensite, 10.0% to 30.0% of bainite, 5.0% to 15.0% of residual austenite, and 0% to 4.0% of a remainder in microstructure,
• a length of a maximum minor axis of the residual austenite is 30 nm or longer, and
• a number density of a carbide having a circle equivalent diameter of 0.1 μm or more and an aspect ratio of 2.5 or less is 4.0×103 pieces/mm2 or less.