355MPa low-welding-crack-sensitivity steel plate and producing method

The invention discloses a 355MPa low-welding-crack-sensitivity steel plate and a producing method, and belongs to the technical field of easy-to-weld structural steel. The steel plate comprises the following components: 0.09-0.13% of C, 0.25-0.35% of Si, 1.20-1.50% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.025-0.04% of Al, 0.02-0.05% of Nb, 0.01-0.03% of Ti, 0.10-0.3% of Cu, 0.10-0.3% of Ni, and the balance of Fe and inevitable impurities; Pcm is not greater than 0.23%, and the carbon equivalent is less than 0.40%; a continuous casting billet which is 400mm in thickness is adopted; and two-stage controlled rolling, controlled cooling and normalizing treatment processes are adopted for production. The produced normalized 10-80mm steel plate has good obdurability; the yield strength is greater than 355MPa; the welding crack sensitivity index is not greater than 0.23%; the carbon equivalent is less than 0.40%; and the steel plate can be used for easy-to-weld steel structures such as fixed offshore oil production and drilling platforms.