| 摘要 |
PURPOSE: A steel sheet having excellent low yield ratio property and a manufacturing method thereof are provided to improve the strength of a steel sheet by controlling the contents of Al, Si, and V. CONSTITUTION: A steel sheet having excellent low yield ratio property comprises C 004~015 weight%, Si 0~02 weight% or less, Mn 18~25 weight%, P 0~0015 weight% or less, S 0~0005 weight% or less, Al 0~020 weight% or less, Mo 001~005 weight%, V 001~005 weight%, N 0~60 ppm or less, and Fe and inevitable impurities of the rest amount. The micro-structure is composed of including ferrite 70~95% and martensite 5~30%. |
