High corrosion-resistant high intensity high Characteristic quarter-phase rustless steel

摘要

PURPOSE: To improve the strength of steel by precipitation strengthening treatment without deteriorating its corrosion resistance and toughness, in precipitation strengthened duplex stainless steel having a specified compsn., by regulating the amounts of components such as C and P into specified ones or below. ;CONSTITUTION: This duplex stainless steel is constituted of, by weight, ≤0.008% C, ≤1.0% Si, 0.1 to 2.0% Mn, ≤0.01% P, ≤0.02% S, 18 to 25% Cr, 3.0 to 7.0% Ni, 1.0 to 4.0% Mo, 1.0 to 4.0% Cu, ≤0.1% Nb, ≤2% W and 0.05 to 0.25% N, and the balance Fe. In this steel, the content of C and P is suppressed to an extremely low degree, by which the precipitation of carbidese can be prevented as possible in the process of precipitation strengthening treatment to attain the purpose, and in the case the content of P exceeds the upper limit, the deterioration in its toughness is remarkably large. Furthermore, the steel can be incorporated with total ≤0.3% of one or more kinds among Ti, Al and Zr as necessary, but, in the case their content exceeds the upper limit, the deterioration in its strength and impact value is remarkably large.;COPYRIGHT: (C)1993,JPO&Japio