Production method of steel plate with low yield ratio, high toughness and high heat input

A production method of a steel plate with low yield ratio, high toughness and large heat input comprises the following steps: smelting, continuous casting, rolling and rapid cooling, and the steel comprises the following chemical components in percentage by mass: 0.13-0.14% of C, 0.10-0.20% of Si, 1.4-1.6% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.03-0.05% of V, 0.012-0.020% of Ti, 0.02-0.05% of Al, 0.0005-0.0009% of B, 0.005-0.008% of N, 2.5-3.5% of Ti and N, and the balance of Fe and inevitable impurities. By controlling components and precipitates and adopting high carbon content and few alloy elements, the yield strength of the obtained steel plate is larger than or equal to 355 MPa, the tensile strength is larger than or equal to 490 MPa, the yield ratio is smaller than or equal to 0.8, the ductility is larger than or equal to 23%, the-20 DEG C impact is larger than or equal to 47 J, the-20 DEG C impact value of each position of a welding joint is larger than or equal