Super-low-carbon steel containing trace tin element and having high strength, corrosion resistance and easy molding and preparation method thereof

The invention discloses super-low-carbon steel containing a trace tin element and having high strength, corrosion resistance and easy molding. The super-low-carbon steel comprises the chemical composition by the mass percentage: 0.001-0.005% of C, 0.001-0.003% of N, 0.1-0.5% of Mn, 0.8-1.50% of Cr, 0.01-0.1% of Mo, 0.1-0.5% of Si, 0.005-0.01% of Al, 0.0001-0.0015% of Mg, 0.0001-0.0015% of Ca, 0.01-0.30% of Sn, 0.01-0.2% of Nb, 0.05-0.3% of Cu, 0.01-0.2% of Ti, 0.001-0.010% of P, not more than 0.003% of S, and the balance Fe. The steel material is prepared by smelting in an induction heating vacuum furnace, ingot casting, hot rolling, pickling and cold rolling, crystallization and annealing, and rolling, wherein the steel material contains trace tin, is low in carbon content and high in strength, has excellent complex workpiece forming performance and resistance to corrosion of oilfield produced water and other aqueous solution, and can be safely used in oil and gas field complex drilling and well completion a