The invention relates to 420 MPa grade alkaline soil
corrosion resistant steel and a preparation method, and belongs to the technical field of steel preparation. The
alkali soil corrosion resistant steel comprises the following chemical components in percentage by
mass: 0.03%-0.12% of C, 0.2%-0.6% of Si, 0.5%-2.0% of Mn, 0.6%-3.5% of Cr, 0.6%-1.2% of Al, 0.001%-0.3% of Mo, 0.001%-0.5% of Ni, 0.001%-0.5% of Cu, less than or equal to 0.008% of P, less than or equal to 0.006% of S, less than or equal to 0.1% of Sn, less than or equal to 0.1% of Sb and a
matrix element Fe. Specific chemical components including C, Si, Mn, Cr, Al, Mo, Ni, Cu and other
alloy elements are designed, the content range of all the elements is strictly controlled, through the
composite effect of all the elements, the steel can form a compact oxidation film in a
corrosion environment, corrosion of a corrosion medium is effectively resisted, and therefore the corrosion resistance of the steel is improved, the service life of the steel is prolonged, and the service life of the steel is prolonged. And a powerful guarantee is provided for long-term application of the steel structure in the northwest alkaline soil environment, and wide application prospects are achieved.