| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength cold-rolled steel sheet that has a tensile strength of 440 MPa or more as well as excellent workability, in particular excellent bendability, at low Mn content, and is excellent in material stability.SOLUTION: There is provided a high-strength cold-rolled steel sheet, which has a constitution in which, in mass%, C: 0.03% or more and 0.15% or less, Si: 1.5% or less, Mn: 0.6% or less, P: 0.05% or less, S: 0.01% or less, Al: 0.08% or less, N: 0.0080% or less, and Ti: 0.04% or more and 0.18% or less, are contained. The area ratio of the ferrite phase is 90% or more, the variation of the area ratio of the ferrite phase within the coil plane is 3% or less, the area ratio of the processed-ferrite to the ferrite phase is 15% or less, the average grain size of the Ti-containing carbide within the crystal grain of the ferrite phase is 10 nm or less, and the ratio of the Ti amount present in a solid solution state in the matrix to the contained Ti amount is less than 10%. |
