Patent ID: 8808471
Filing Date: 2014-08-19
Classification: C21D,C22C

Abstract:
1. A martensitic stainless steel alloy strengthened by copper-nucleated nitride precipitates, said alloy comprising, in combination by weight percent, about 10.0 to about 12.5 Cr, about 2.0 to about 7.5 Ni, up to about 17.0 Co, about 0.6 to about 1.5 Mo, about 0.5 to about 2.3 Cu, up to about 0.6 Mn, up to about 0.4 Si, about 0.05 to about 0.15 V, [N] up to about 0.10 N, [C] up to about 0.035 C, up to about 0.01 W, and the balance Fe and incidental elements and impurities, said alloy having a microstructure substantially absent cementite [carbides] and comprising a martensite matrix with nanoscale copper particles and alloy nitride precipitates selected from the group consisting of alloy nitride precipitates enriched with a transition metal nucleated on the copper precipitates, alloy nitride precipitates having a hexagonal structure, alloy nitride precipitates including one or more alloying elements selected from [the group]Fe, Ni, Cr, Co and Mn coherent with the matrix, and alloy nitride precipitates having two dimensional coherency with the matrix said alloy substantially free of cementite [carbide] precipitates.