| 摘要 |
PURPOSE: A steel sheet with excellent yield strength and stretch-flangeability and a manufacturing method thereof are provided to cost-efficiently manufacture the steel sheet and to improve weldability. CONSTITUTION: A steel sheet with excellent yield strength and stretch-flangeability comprises C 0.02~0.1 weight%, Si 0.1~2.5 weight%, Mn 0.1~2.3 weight%, Cr 0.01~1.5 weight%, Al 0.02~0.1 weight%, Nb 0.01~0.08 weight%, Ti 0.5*48/14*N content~0.1 weight%, P less than 0.05 weight%, S less than 0.015 weight%, Fe, and inevitable impurities. The yield strength of the steel sheet is more than 600MPa, and the tensile strength is more than 780MPa. |
