Steel sheet and component including same

Abstract

The present invention provides a steel sheet having excellent hole expandability and excellent crack resistance in spite of having high strength, as well a component including the same. Provided is a steel sheet that is characterized by having a prescribed chemical composition and comprising, by area%, 5-50% ferrite, a total of 50-90% martensite and bainite, and 5% or less remainder structure, wherein Fb / Fa, which is the ratio of the area ratio Fb of ferrite in a location that is 1 / 15 of the sheet thickness from the surface to the area ratio Fa of ferrite in a location that is 1 / 50 of the sheet thickness from the surface, is 0.45-0.60, and Fc / Fa, which is the ratio of the area ratio Fc of ferrite in a location that is 1 / 4 of the sheet thickness from the surface to the area ratio Fa of ferrite in the location that is 1 / 50 of the sheet thickness from the surface, is 0.25-0.50.