Patent ID: 8753457

Claim:
A process for nitriding martensitic stainless steels comprising: a. heating martensitic stainless steels to a temperature of from about 900° F. (480° C.) to about 2500° F. (1370° C.) in a vacuum furnace in the presence of hydrogen or argon gas in order to clean the surface thereof; b. subsequently removing the hydrogen or argon gas from said furnace; c. injecting nitrogen (N 2 ) gas, ammonia gas (NH 3 ) or mixtures thereof as a pulsed injection into the chamber of said furnace which is at a partial atmospheric pressure of from about 500 torr to about 700 torr; d. nitrating said steel at a temperature of from about 1400° F. (760° C.) to about 2200° F. (1205° C.); e. quenching said steel, and, f. raising the temperature of the chamber in said furnace a second time from about 900° F. (480° C.) to about 2500° F. (1370° C.) prior to cooling the final product.