| 摘要 |
<p>Provided are a cold-rolled steel sheet which undergoes a small load at the time of cold-rolling, has excellent press formability and high strength, and a method of manufacturing the cold-rolled steel sheet. A hot-rolled steel sheet which has the composition consisting of, by mass%, 0.10 to 0.30 C, 0.2 or more Mn, 0.01 or more Ni, 0.5 to 2.5 Mn+Ni, 1.2 to 9.0 Cr, and Fe and unavoidable impurities as a balance and has a tensile strength of 1000 MPa or less is subjected to pickling and, thereafter, is subjected to cold rolling at a total rolling reduction of 60 % or more thus forming a cold-rolled steel sheet, and final continuous annealing treatment is performed at a soaking temperature of 750 °C or above and at a cooling rate of 3 °C/s to 100 °C/s so that the cold-rolled steel sheet which has a tensile strength of 1280 MPa or more, breaking elongation of 3 % or more and a thickness of 0.05 to 0.60 mm is manufactured.</p> |
