The invention discloses an HPS420WZ35 weather-resistant bridge plate with the thickness of 100 mm and a production method for ensuring the performance of the HPS420WZ35 weather-resistant bridge plate, the HPS420WZ35 weather-resistant bridge plate comprises the following chemical components of C, Si, Mn, P, S, Als, Nb, Cr, Mo, V, Ni, Cu, Ti, B, Sn, N and the balance Fe and residual elements, and the production method is achieved through the following steps of blank selection, steel billet treatment, steel billet heating, steel billet rolling, steel plate controlled cooling, steel plate straightening and steel plate
slow cooling. In the aspect of component design, segregation is favorably reduced and the
welding performance is improved by controlling the contents of strengthening elements such as C and Mn; and by adding
alloy elements such as Mo and Cr, the through
quenching capacity of the 100 mm extra-
thick plate in the cooling process is improved, a fine and uniform B structure can be obtained easily, and the strength is improved. The HPS420WZ35 weather-resistant bridge plate with the thickness of 100mm is fine and uniform B + F + P three-phase structure, the strength and the low-temperature
impact toughness are matched, and the comprehensive performance is excellent.