Production method of Q500-grade offshore structural steel with high corrosion resistance and high strength

The invention discloses a production method of Q500-grade offshore structural steel with high corrosion resistance and high strength. The production method comprises the process steps of molten iron pretreatment, converter steelmaking, external refining LF, vacuum treatment RH, continuous casting, heating, rolling, controlled rolling cooling, tempering, finishing, performance inspection and ultrasonic flaw detection. The steel comprises the following components in percentage by mass: 0.03 to 0.07 percent of C, 0.15 to 0.40 percent of Si, 1.20 to 1.30 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.003 percent of S, 0.04 to 0.06 percent of Nb, 0.01 to 0.02 percent of Ti, 0.02 to 0.05 percent of Als, 0.30 to 0.70 percent of Cu, 0.7 to 1.5 percent of Ni, 0.15 to 0.30 percent of Cr and the balance of Fe and inevitable impurity elements. The thickness specification of the produced steel plate is smaller than or equal to 60 mm, and the steel plate has a marine atmosphere corrosion e