| 摘要 |
<p>Provided are a high-strength cold-rolled steel sheet which has a TS of 440MPa or above and excellent weldability and which neither forms humping beads even when subjected to high-speed plasma welding and nor brings about deterioration in the workability of a tailored blank, and a process for production of same. A high-strength cold-rolled steel sheet which has a TS of 440MPa or above and excellent weldability, characterized by having a composition which contains by mass C: 0.0005 to 0.005%, Si: 0.1 to 1.0%, Mn: 1 to 2.5%, P: 0.01 to 0.2%, S: 0.015% or less, sol. Al: 0.05% or less, N: 0.007% or less, Ti: 0.01 to 0.1%, B: 0.0005 to 0.0020%, Cu: 0.05 to 0.5%, and Ni: 0.03 to 0.5% with the balance being Fe and unavoidable impurities and a ferrite single phase structure.</p> |
