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.