A CF8C type stainless steel alloy and articles formed therefrom containing
about 18.0 weight percent to about 22.0 weight percent chromium and 11.0
weight percent to about 14.0 weight percent nickel; from about 0.05
weight percent to about 0.15 weight percent carbon; from about 2.0 weight
percent to about 10.0 weight percent manganese; and from about 0.3 weight
percent to about 1.5 weight percent niobium. The present alloys further
include less than 0.15 weight percent sulfur which provides high
temperature strength both in the matrix and at the grain boundaries
without reducing ductility due to cracking along boundaries with
continuous or nearly-continuous carbides. The disclosed alloys also have
increased nitrogen solubility thereby enhancing strength at all
temperatures because nitride precipitates or nitrogen porosity during
casting are not observed. The solubility of nitrogen is dramatically
enhanced by the presence of manganese, which also retains or improves the
solubility of carbon thereby providing additional solid solution
strengthening due to the presence of manganese and nitrogen, and combined
carbon.