Maximum-thickness S355G10+N steel plate for ocean platform and production method of steel plate

The invention discloses a maximum-thickness S355G10+N steel plate for an ocean platform and a production method of the maximum-thickness S355G10+N steel plate. The production method of the maximum-thickness S355G10+N steel plate comprises smelting, casting, heating, rolling, cooling and heat treatment processes. The maximum-thickness S355G10+N steel plate comprises the following chemical ingredients in percentage by weight: 0.08-0.12% of C, 0.15-0.50% of Si, 1.40-1.65% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.040-0.060% of V, 0.020-0.030% of Nb, 0.020-0.050% of Al, less than or equal to 0.43% of Cea, less than or equal to 0.22% of Pcm and the balance of Fe and inevitable impurities. The maximum-thickness S355G10+N steel plate has the advantages that low-carbon and high-microalloying design thought is adopted in composition design, the problem of segregation of carbon and manganese is solved, and the requirements such as high strength, high impact toughness and wide cold bending performance are met; hardenability of the maximum-thickness S355G10+N steel plate is guaranteed under the low-carbon and low-equivalent carbon content conditions, and the maximum-thickness S355G10+N steel plate has good structure and overall performance and welding performance; and the maximum-thickness S355G10+N steel plate has good mechanical properties, welding performance and processability and can meet requirements of construction technological conditions of an ocean engineering equipment manufacturing plant.