The invention discloses a diphase stainless steel, which comprises the following components in percentage by weight: less than or equal to 0.05 percent of C, 0.2 to 1.0 percent of Si, 0 to 2.0 percent of Mn, 22 to 27 percent of Cr, 0 to 2.0 percent of W, less than or equal to 0.1 percent of S, less than or equal to 0.03 percent of P, 0 to 0.003 percent of B, more than 0 and less than or equal to 0.2 percent
rare earth of which the Ce content is more than 50 percent, and the balance of Fe and inevitable impurities, wherein a
casting blank of the diphase stainless steel comprises over 60 percent of isometric
crystal. A method for manufacturing the diphase stainless steel comprises the following steps of: performing
smelting,
die casting or
continuous casting to form the
casting blank, wherein the thickness of a steel die is more than 30 mm during the
die casting to ensure that the cooling velocity of the steel is more than 10 DEG C per minute, and in the process of the
continuous casting, the degree of
superheating of the
casting is between 30 and 100 DEG C, and the casting speed is over 1.2 meters per minute; putting the casting blank into a
heating furnace, heating the casting blank to the temperature of between 1,100 and 1,250 DEG C, performing heat preservation on the casting blank, and then
forging or hot-rolling the casting blank to a required thickness; and annealing and
pickling a steel plate or a plate coil after
forging or hot-rolling, and controlling the annealing temperature to be between 1,000 and 1,100 DEG C. The diphase stainless steel has high
corrosion resistance and high hot-working performance, and can be widely applied in the fields of
petroleum,
chemical industry,
papermaking,
marine engineering and the like in rigorous
corrosion environments.