STEEL SHEET AND PRODUCTION METHOD THEREFOR

Provided is a steel sheet that has a TS of 1320 MPa or more and enables a component produced by blanking the steel sheet by shearing or slitting or drilling holes in the steel sheet by punching and subsequently cold-pressing the steel sheet or by cold-pressing the steel sheet and cutting the resulting component by shearing or drilling holes in the component by punching to have excellent delayed fracture resistance. Also provided is a method for producing the steel sheet. The steel sheet has a specific composition and a microstructure including martensite and bainite. The total area fraction of the martensite and the bainite to the entirety of the microstructure is 95% or more and 100% or less. The balance of the microstructure is one or two of ferrite and retained austenite. The microstructure includes specific inclusion clusters, the content of the inclusion clusters in the microstructure being 5 clusters/mm 2 or less. The microstructure includes prior-austenite grains having an average size of more than 5 µm. The steel sheet has a tensile strength of 1320 MPa or more.