Steel sheet, member, and methods for producing the same

A steel sheet comprising:

• a chemical composition containing, in mass %,
• C:
• 0.10% or more and 0.30% or less,
• Si:
• 0.5% or more and 2.0% or less,
• Mn:
• 1.5% or more and 3.0% or less,
• P:
• 0.10% or less,
• S:
• 0.020% or less,
• sol. Al:
• 1.00% or less,
• N:
• 0.015% or less, and
• the balance being Fe and incidental impurities;
• and
• a steel microstructure containing, in area fractions,
• a microstructure composed of at least one of ferrite and bainitic ferrite:
• 10% or more and 60% or less,
• a microstructure composed of at least one of tempered martensite and lower bainite:
• 20% or more and 80% or less,
• retained austenite:
• 5% or more, and
• fresh martensite:
• 10% or less,
• wherein:
• an average C concentration in the retained austenite is 0.60 mass % or more, and
• in a region within 100 μm from a steel sheet surface in a thickness direction, a content of Fe element present as carbides in the tempered martensite is 0.20 mass % or less on average,
• and optionally the steel sheet comprises a zinc coating layer on the steel sheet surface.