| abstract |
A cold-rolled steel sheet suitable for a CPU socket frame and a CPU fixing cover used for attaching a CPU chip to a wiring board is obtained. SOLUTION: C: 0.01-0.20%, Si: 0.5% or less, Mn: 1.5% or less, P: 0.05% or less, S: 0.01% or less, Acid-soluble Al: 0.005-0.10%, N: 0.007% or less If necessary, and / or a steel continuous cast slab containing Nb: 0.01 to 0.15% by mass is hot-rolled and cold-rolled at a cold rolling rate of 20 to 50% after pickling. Because it is processed enhanced by cold rolling, the 0.2% yield strength: 600N / mm 2 or more, tip radius: 0.7 mm or less bending workability, accuracy of plate thickness: 20 [mu] m or less and excellent characteristics are imparted. [Selection figure] None |