HIGH STRENGTH AND LEAN-DUPLEX STAINLESS STEEL AND METHOD OF MANUFACTRUING THE SAME

摘要

High-strength and low-alloy-type duplex stainless steel that has pitting resistance at a level applicable to general corrosion-resistance environments (aqueous solution environment of about 200 ppm NaCl or less) by controlling alloy composition and phase fraction control, and is economical and capable of securing high strength and high elongation; The manufacturing method is disclosed. High-strength and low-alloy duplex stainless steel according to the present invention is Cr: 21.0 to 22.5 wt%, Mn: 4.0 to 6.2 wt%, Ni: 0.5 to 1.0 wt%, W: 1.0 to 2.0 wt%, Mo: 0.5 to 0.9 wt%, N: 0.32 to 0.45 wt%, C: 0.06 to 0.09 wt% and the remaining Fe and unavoidable impurities, characterized in that the austenite phase has a structure fraction of 55 to 60 vol%.