LOW CR AND LESS NI TYPE HIGH CORROSION RESISTANT DUPLEX STAINLESS STEEL

摘要

PURPOSE:To obtain the duplex stainless steel having excellent corrosion resistance in a high temp. and low concn. chloride environment, at the time of manufacturing a stainless steel, by regulating the content of Cr and Ni and transforming its structure into a dualphase structure constituted of a ferrite phase and an austenite phase in a specified ratio. CONSTITUTION:At the time of manufacturing a stainless steel, the one having a compsn. constituted of, by weight, 0.03% C, 1% Si, 1% Mn, 0.04% P, 0.03% S, 18 to 22% Cr, 3 to 5% Ni, 1 to 3% Mo, 0.08 to 0.20% N and the balance Fe and in which 30 to 70% of the structure is constituted of a ferrite(alpha)phase and the balance an austenite (gamma)phase is manufactured. By reducing the amt. of expensive Ni as an austenitizing element to be used, the ferrite- austenite duplex stainless steel which is low-cost and having high corrosion resistance can be manufactured.