STEEL SHEET, MEMBER, METHODS FOR PRODUCING THESE, METHOD FOR PRODUCING HOT-ROLLED STEEL SHEET FOR COLD-ROLLED STEEL SHEET, AND METHOD FOR PRODUCING COLD-ROLLED STEEL SHEET

Provided are a steel sheet having a tensile strength (TS) of 440 MPa or more and less than 780 MPa and excellent in crashworthiness, a member, and methods for manufacturing the steel sheet and the member.A steel sheet has a chemical composition satisfying a carbon equivalent (CE) of 0.18% or more and less than 0.46% and a specific steel microstructure. In the steel sheet, an average crystal grain size of ferrite is 25 um or less, coefficient of variation (CV) of ferrite grain size × carbon equivalent (CE) is 0.25 or less, when the steel sheet is bent by 90° in a rolling (L) direction with a width (C) direction as an axis at radius of curvature/sheet thickness: 4.2 and then unbent to be flattened again, the ratio (NFvoid/NF) of ferrite grains having a void at an interface to all ferrite grains is 5% or less in an L section in a region extending by 0 to 50 um from a steel sheet surface on a compressive-tensile deformation side, and a tensile strength is 440 MPa or more and less than 780 MPa.