Duplex stainless steel and formed object thereof

A duplex stainless steel, having a composition consisting of in weight % (wt %):

• C 0.010 to 0.015;
• Si 0.08 to 0.23;
• Mn 1.0 to 1.05;
• Cr 29.07 to 29.92;
• Ni 5.76 to 7.17;
• Mo 3.0 to 4.0;
• N 0.3 to 0.35;
• S max 0.008;
• P max 0.008;
• at least one of Ti, Nb, Hf, Ca, Ba, V, and B max 0.5 total;
• and
• balance Fe and unavoidable occurring impurities,
• wherein sigma phase is max 0.5 wt %,
• wherein the duplex stainless steel has an austenite spacing of 1.2 microns,
• wherein the duplex stainless steel has a corrosion rate of 0.191 mm/year,
• wherein the corrosion rate is evaluated on a sample of the duplex stainless steel in an oxygen-free carbamate solution at a temperature of 210° C. for 14 days, and
• wherein the sample is in the form of a coupon having dimensions of 20×10×3 mm obtained from a 5 mm strip produced by hot warming to 1200° C. and cold rolling at room temperature with intermediate annealing at 1100° C. and final annealing at 1070° C., and surfaces of the sample were machined and finished by wet grinding.