HIGH FUNCTIONAL DUPLEX STAINLESS STEEL HAVING A MINIMIZED CONTENT OF MOLYBDENUM AND A HIGH CONTENT OF TUNGSTEN

摘要

Improved duplex phase stainless steel is provided which is able to prevent embrittlement owing to formation of sigma phase being a problem of prior duplex phase stainless steel, without deterioration of corrosion resistance, The duplex phase stainless steel consists of 20 to 23 wt% of Cr, 4 to 7 wt% of Ni, 0.1 to 0.35 wt% of N, 1 to 4 wt% of W, 0.5 to 1.0 wt% of Mo, 0.8 wt% in maximum of Si, 2.0 wt% in maximum of Mn, 2.0 wt% in maximum of Cu, 0.18 wt% in maximum of Ce, 0.007 wt% in maximum of B, 0.05 wt% in maximum of C, 0.03 wt% in maximum of S, 0.04 wt% in maximum of P, balance of Fe and indispensable impurities. The duplex phase stainless steel has hardly exhibit decrease of impact toughness due to the formation of sigma phase, thereby enabling manufacture of large-sized casting product or forging product.