| 摘要 |
PURPOSE: An ultra high strength cold rolled steel sheet and a method for manufacturing the same are provided to obtain a cold rolled steel sheet with high strength of 1GPa or greater and improved shape property by controlling component system and manufacturing conditions. CONSTITUTION: An ultra high strength cold rolled steel sheet comprises C of 0.1-0.3%, Si of 0.1-1.5%, Mn of 2.0-3.0%, P of 0.001-0.10%, S of 0.010%, Al of 0.01-0.1%, Cr of 0.3-1.0%, B of 0.0010-0.0030%, Ti of 0.01-0.1%, N of 0.001-0.01%, one or more selected from the group consisting of Nb of 0.02-0.05%, Mo of0.01-0.2%, V of 0.01-0.2%, and W of 0.01-0.2%, and Fe and inevitable impurities of the remaining amount. Ti and N satisfy the relation of 3.4 <= Ti/N <= 10. |
