| 摘要 |
A cold-rolled steel plate having favorable heat spot resistance, favorable antiwear performance, and favorable punching performance is provided. The cold-rolled steel plate has a chemical composition containing, on the basis of percent by mass, C from 0.03 to 0.08%, Si from 0 to 1.0%, Mn from 0.2 to 0.8%, P at 0.03% or less, S at 0.01% or less, and Al at 0.05% or less so as to satisfy the following relationship: 5 * C% - Si% + Mn% - 1.5 * Al% < 1. The chemical composition further contains, on the basis of percent by mass, at least one of Nb from 0.03 to 0.4%, V from 0.01 to 0.3%, and Ti from 0.01 to 0.3% so as to satisfy the following relationship: 0.04 < (Nb%/1.4) + (V%/1.1) + Ti% < 0.3. An average diameter of particles of a carbide as a precipitate is from 20 to 100 nm. A second phase structure having a longitudinal diameter of 5 µm or more has an area fraction of 5% or less in a cross-sectional structure. |
