HIGH-NITROGEN LOW-NICKEL DUPLEX STAINLESS STEELS WITH AN EXCELLENT PITTING CORROSION RESISTANCE

摘要

PURPOSE: A high functional nickel (Ni)-free-high nitrogen duplex stainless steel having a high pitting corrosion resistance is provided to exclude Ni increasing price instability and environmental burden for the steel, thereby improving economic efficiency, price stability, and eco-friendliness for the steel. CONSTITUTION: A high functional nickel (Ni)-free-high nitrogen duplex stainless steel having a high pitting corrosion resistance is formed with a ferrite-austenite phase. The steel includes 16.5 to 19.5 wt% of Cr, 2.5 to 3.5 wt% of Mo, 1.0 to 5.5 wt% of W, 5.5 to 7.0 wt% of Mn, 0.35 to 0.45 wt% of N, 0.01 to 0.7 wt% of Ni, and remnant Fe and impurities having below 0.03 wt% of C and below 0.5 wt% of Si. The volume fraction of a ferrite phase in the steel is 40 to 60%. [Reference numerals] (AA) Comparison example 1; (BB) Comparison example 2; (CC) Comparison example 3; (DD) Implementation example 1; (EE) Implementation example 2; (FF) Implementation example 3