| abstract |
The present invention provides a high-strength steel sheet excellent in workability in which ductility and hole expandability are compatible. SOLUTION: C: 0.08 to 0.3%, Si: 0.25 to 1.1%, Mn: more than 2%, 3.5% or less, P: 0.028% or less, S: 0.01 % Or less, sol. Al: 0.03 to 1%, and N: 0.01% or less, if necessary, Cu: 1% or less, Ni: 1% or less, Cr: 1% or less, Mo: 0.5% or less and B: having a steel composition containing one or more selected from the group consisting of 0.005% or less, the steel structure comprising ferrite, a low-temperature transformation phase and residual austenite, and the volume fraction VF of the ferrite Is 0.1 to 0.80, the residual austenite volume fraction VA is 0.30 or less, and the particle size of the carbide contained in the low-temperature transformation phase is 500 nm or less, which satisfies the following formula. 0.2 ≦ (Si + Al) / (Mn + Ni) ≦ 0.80 0.15 ≦ C / (1-VF) ≦ 0.50 [Selection figure] None |