6-8mm thin Q345qE high-performance bridge steel plate and manufacturing method thereof

The invention relates to the technical field of special steel and smelting of the special steel, in particular to a 6-8mm thin Q345qE high-performance bridge steel plate and a manufacturing method thereof. The bridge steel plate comprises, by mass, 0.05%-0.13% of C, 0.10%-0.50% of Si, 1.00%-1.50% of Mn, 0.001%-0.020% of P, 0.001%-0.010% of S, 0.010%-0.050% of Nb, 0.006%-0.030% of Ti, 0.010%-0.040% of Als, 0.0015%-0.0060% of N and the balance Fe and a small amount of unavoidable impurity elements. The carbon equivalent of the steel is smaller than or equal to 0.38% and far lower than the national standard requirement of 0.43%, and the steel has good welding performance; the yield strength is 360-490 MPa, the tensile strength is 500-603 MPa, the ductility is not lower than 23%, and the obdurability is good; the yield ratio is not greater than 0.83, and the anti-seismic property is good; the Charpy impact energy of a V-shaped notch at-40 DEG C is greater than or equal to 90J, and the low-temperature impact tough